Conference Agenda

Basic research rarely helps practitioners directly with their everyday concerns; nevertheless, it stimulates new ways of thinking that have the potential to revolutionize and dramatically improve how practitioners deal with a problem in the future*. This lecture aims at providing an example.

At the dawn of the new millennium, attosecond metrology enabled us to capture sub-atomic motions for the first time. Couple of decades later, the new technology paves the way towards precision preventive medicine.

When triggered and captured in the molecules of human blood, these motions can reveal changes in its molecular composition and provide early signs of unfolding health abberations.

Cost-effective monitoring of human health will address several grand challenges of our time.

*https://en.wikipedia.org/wiki/Basic_research

Ferenc Krausz graduated in electrical engineering from the Budapest University of Technology and completed his studies in theoretical physics at the Eötvös Loránd University in 1985. He earned his doctorate in laser physics from the Technische Universität Wien (1991), where he became professor in 1998. In 2003-2004, he was appointed director at the Max-Planck-Institute of Quantum Optics in Garching and chair of experimental physics – laser physics at the Ludwig-Maximilians-Universität and established “Attoworld” at these two sites (attoworld.de). In a series of experiments performed between 2001 and 2004 his team succeeded in producing and measuring isolated attosecond pulses of light and applying them to observe sub-atomic motions. Attoworld has been fostering the proliferation of the emerging field, attosecond science, and – since 2015 – exploring its utility for probing human health. For his contributions to establishing the field of Attosecond Science, Ferenc Krausz has been awarded – among others – the King-Faisal International Prize for Science (2013), the Wolf-Prize in Physics (2022), the BBVA Frontiers of Knowledge Award (2023) and the 2023 Nobel Prize in Physics.

Advances in intraoperative imaging have reshaped neurosurgical precision, yet real‑time molecular feedback remains underutilized. In this keynote, we explore three surgical scenarios where spectroscopy could markedly enhance decision‑making and patient outcomes. First, during glioblastoma resection, distinguishing infiltrative tumor margins from eloquent cortex is challenging; intraoperative Raman or fluorescence spectroscopy promises to delineate residual neoplastic tissue beyond the resolution of visual inspection and neuronavigation. Second, in intramedullary spinal tumor surgery, continuous neurophysiological monitoring guides functional preservation, but lacks biochemical insight; combining spectroscopy with somatosensory and motor‑evoked potentials could detect early metabolic alterations in cord tissue, preempting irreversible injury. Third, in vascular neurosurgery—such as aneurysm clipping and arteriovenous malformation resection—spectroscopic measurement of ischemic metabolites (lactate, cytochrome redox state) could provide an immediate alert to compromised perfusion before clinical or Doppler changes arise. Collectively, these examples illustrate how integrating spectroscopy into the operating theatre may transform neurosurgical practice by delivering real‑time molecular intelligence, improving margin control, safeguarding neural function, and optimizing vascular safety.

Heritage Science is the interdisciplinary field that combines the humanities, sciences, and technological innovation to study, preserve, and promote cultural heritage. Within this context, spectroscopy serves as a powerful analytical tool for investigating the material of heritage objects. By providing detailed molecular and elemental information, spectroscopy enables researchers to identify original materials, restoration, and degradation products, and monitor conservation treatments. This contributes to the conservation and restoration of artifacts, but also to a deeper understanding of our tangible Cultural Heritage.

Spectroscopy stands as a cornerstone analytical technique within the first European Research Infrastructure for Heritage Science (E-RIHS ERIC). MOLAB and FIXLAB platforms of ERIHS give access to state of the art analytical spectroscopic methods (either noninvasive, portable and benchtop ones) to study from the nano to the macro scale Cultural Heritage material composition and behaviour.

MOLAB, the access platform of portable analytical tools allowing for noninvasive in situ studies, started more than 20 years ago, driven by the need of fully respecting the uniqueness and preciousness of Cultural Heritage items, while understanding their materiality and state of conservation. Over these two decades, MOLAB has continuously evolved, motivated by the need to address the complex and multidisciplinary challenges posed by Heritage Science, offering state of the art, advanced techniques and methods.

Recent technological advancements, marking the transition from single-point measurements to hyperspectral imaging, and from purely spectral to spectrally and spatially resolved chemical imaging, will be presented. Multimodal and multiscale approaches, combining well-established techniques with methods relatively new in the field of Heritage Science, will be also discussed. These developments underscore the pivotal role of spectroscopy in this interdisciplinary domain, highlighting its capacity to reveal complex material information while supporting noninvasive investigation and conservation efforts.

Hemoglobin (Hb), a key iron-containing biomolecule responsible for oxygen transport, serves as a critical biomarker for diagnosing disorders such as β-thalassemia and sickle cell anemia. Traditional blood assays for Hb analysis often suffer from high cost, long processing times, and limited accessibility. Addressing these challenges, we present a novel nano-biosensing platform based on Surface-Enhanced Raman Spectroscopy (SERS) for rapid, specific, and reproducible detection of Hb from less than 10 µL sample volume.

The sensor substrate comprises of gold and silver thin films fabricated via pulsed laser ablation and electrochemical deposition, optimized for excitation with 532 nm and 633 nm lasers. These nanofilms were functionalized with a synthesized heteroaromatic ligand (L), derived from α-lipoic acid and 2-(2-pyridine)imidazo[4,5-f]-1,10-phenanthroline. The lipoic acid moiety anchors the ligand to the nanometallic surface, while the phenanthroline unit exhibits strong affinity to the iron center in the heme group, enabling high specificity toward Hb.

The developed sensor demonstrates high stability with consistent performance. Detection is based on the appearance of a characteristic SERS band at 1390 cm⁻¹, associated with the porphyrin methine bridge in Hb. This signal scales reliably with Hb concentration and enables differentiation of Fe²⁺/Fe³⁺ redox states, corresponding to oxyHb and deoxyHb forms, offering insight into the oxygen-carrying capacity of blood. Density Functional Theory-Molecular Dynamics (DFT-MD) simulations supported experimental spectral assignments, validating vibrational features of ligand L and Hb interactions.

Infrared spectroscopy, coupled with multivariate analysis, has become a valuable tool for biofluid analysis and particularly urine. However, it often requires extensive calibration with real samples or artificial urine spiked with standards. The prediction of UACR (Urinary Albumin to Creatinine Ratio), a key diagnostic marker for Diabetic Kidney Disease (DKD), requires the optimization the experimental conditions to obtain the best prediction for both albumin and creatinine. To reduce experimental time and resource consumption, we propose using in-silico simulated spectra to contribute to design experiment and optimization. We follow a bottom-up approach and simulate urine spectra based on linear combinations of the pure infrared spectra of the most abundant urine components. Resulting simulated spectra are comparable to the artificial and real samples except for minor contaminants from the preconcentration membrane filters. Different experimental conditions, such as preconcentration factors are tested, and obtained calibration models are almost identical for simulated and artificial datasets. Once experimental conditions are optimized, we process the real urine samples accordingly. Resulting machine learning models yield similar quantification and classification prediction errors when compared to models calibrated with in silico datasets. These findings highlight that simulated spectra are effective in guiding experimental design by helping to discard suboptimal pretreatment conditions, ultimately reducing resource use.

Epidemiological surveys indicate that Autism Spectrum Disorder (ASD) cases are on an increasing trend worldwide. The etiology of this multifactorial neurodevelopmental disorder is still unclear, but it is thought to be linked to both genetic and environmental factors [1]. Among the latter, exposure to neurotoxicants, and particularly to metallic pollutants, is increasingly thought to play a significant role in the onset of ASD in pediatric patients. While early diagnosis is crucial, ASD nowadays is still largely diagnosed based on behavioral evaluation and developmental history, with two typical pitfalls: 1) different disorders can manifest with similar symptoms; 2) behavioral changes may go unnoticed and the disorder undiagnosed for extended periods of time.

In this work, we present our first results on the development of a spectroscopic method to obtain a metallomic profile linked to ASD with the goal of improving the accuracy of its diagnosis and, in the medium-long term, its treatment and prevention. To this end, we employed Laser-Induced Breakdown Spectroscopy (LIBS) to interrogate aqueous solutions and microdrops of blood serum deposited and dried on solid substrates and withdrawn from ASD subjects and healthy controls.

Moreover, we will discuss the effect on the intensity of LIBS spectra intensity, and on the consequent classification ability, of two substrate-modification methods for the analysis of trace elements, the first based on the generation of Laser-Induced Periodic Surface Structures (LIPSS), the second based on the substrate functionalization with noble-metal nanoparticles, prior to the LIBS analysis of the deposited fluids.

Historical textiles of functional and decorative significance represent an essential part of our cultural heritage. Their scientific analysis, conducted using advanced analytical techniques, complements historical research and provides a deeper understanding of their material composition, production methods, cultural background, and changes they undergo due to aging and environmental exposure.

A key aspect of studying historical textile is analysing their colouring matter. In the case of the most commonly used natural dyes – mordant dyes – this includes examining both the organic colouring compounds from dyes and metals introduced through mordants. Before the dyeing process, yearns are treated with a mordant – an aqueous solution of aluminium salts or transition metals (e.g., copper, chromium, iron, tin). This treatment facilitates the bonding of dye molecules to the fibre via metal cations deposited on the fibre surface, forming stable colour complexes. The type of mordant used affects the distribution and electron density within the complex, ultimately determining the final hue of the colourations. Therefore, a comprehensive understanding of the nature of colour produced by mordant dyes is essential for accurately reconstructing the original appearance of historical objects. This requires studying both the organic and inorganic components of the colouring matter.

The study of mordant metals has often been neglected or limited to non-invasive techniques that provide only superficial information. Although such techniques are preferred and favoured in the study of heritage objects, invasive and destructive techniques often yield more detailed, accurate, and unequivocal information about historical artifacts, such as the identification of organic dyes in fabrics. However, the small amount of material available for analysis – often less than 1 mg – poses a significant challenge to the use of conventional analytical methods. This obstacle highlight the need to develop more effective and reliable analytical procedures tailored for analysing small sample quantities, particularly for the identification of mordants in historical textiles.

In this study, we employed inductively coupled plasma optical emission spectroscopy (ICP-OES) for this purpose. This technique guarantees multi-element quantitative analysis of both main and trace components within a sample in a single analytical run. To adapt ICP-OES for the analysis of precious historical objects, it was necessary to modify the conventional continuous sample introduction system. Specifically, a novel system combining flow injection analysis (FIA) and multimode sample introduction system (MSIS) was developed. FIA reduces the required sample volume to just 20 µL, while the MSIS chamber integrates the advantages of classical pneumatic nebulization (PN) with hydride generation of the analysed elements (HG). This combination allows for the detection of easily excitable elements as well as those requiring enhanced sensitivity – such as tin, a mordant metal that is particularly challenging to analyse.

The developed FIA-PN/HG-ICP-OES system was employed to establish an analytical procedure for the determination of mordant metals in objects of historical significance. The method development involved optimizing both instrumental parameters and hydride generation conditions, with particular focus on improving the efficiency of tin hydride formation. To ensure the reliability and accuracy, the method was validated by analysing of certified reference materials (CRM) – rye grass (ERM®-CD281) and marine sediment (PACS-2). Following validation, the method was successfully applied to characterize mordants in samples collected from ancient textiles, demonstrating its suitability for use in archaeometric studies of heritage artifacts.

Plasma-mediated vapor generation (PMVG) is a recent and advanced sample introduction technique compatible with atomic spectrometric detection of elements at trace levels. The plasma, typically generated in a dielectric barrier discharge (DBD) reactor, produces various reactive species responsible for analyte conversion into a gas phase. PMVG does not require chemical reagents and has been proven highly efficient in several applications [1].

Although PMVG has been applied to a considerable range of analytes and sample matrices, it remains predominantly limited to liquid samples. In such system, PMVG from liquid samples is believed to proceed via interaction of analytes with reactive species produced especially in the plasma-liquid interface, including hydrated electrons and hydrogen radicals, which have a high reduction potential, being thus likely responsible for analyte reduction in solution and production of volatile species [1]. Direct PMVG from solid samples has not yet been reported. Solid samples are typically treated by digestion or extraction to release the analyte from the matrix into the solution prior to introduction into the PMVG reactor. However, these sample preparation methods are often time-consuming and require multiple reagents. To overcome this limitation, the present work investigates the possibility of direct treatment of solid samples by PMVG for mercury determination.

A lab-made 3D-printed PMVG reactor was constructed in a DBD configuration, i.e., using two copper electrodes separated by quartz barriers. For sample introduction, approximately 20 mg of raw fish tissue (shark) was placed on a small piece of fiberglass paper (10 x 10 mm), which was inserted into the reactor. Argon was used as a discharge and carrier gas at 50 mL min^-1. The electrodes were connected to a lab-made high-voltage sinusoidal power supply, delivering 3 kV. The reactor's gas output was connected to a cold dryer (-2 °C) for water vapor condensation, followed by an amalgamator tube filled with ca. 30 mg of gold-coated alumina to preconcentrate Hg released from the solid sample during the PMVG step. The amalgamator was kept at room temperature during the PMVG stage, while it was subsequently electrically heated to 700 °C to release the trapped Hg. The gas output was connected to a T-shaped quartz absorption cell (unheated), positioned in the optical path of an atomic absorption spectrometry (AAS) instrument.

The calibration curve was linear across the entire concentration range tested (10 to 1000 µg L^-1 of MeHg⁺, 20 µL), with a coefficient of determination of 0.9996. Peak height of the transient signal was used as the measurement criterion rather than peak area due to the lower relative standard deviation (< 10%). The limit of detection was 3 µg kg^-1 (50 pg Hg absolute). The use of the amalgamator results in significant improvement of the limit of detection, since all the Hg gradually volatilized from the solid sample during the PMVG step (180 s) was rapidly released from the amalgamator, resulting in a narrow peak (full width at half maximum of 4 s). A comparison between standard solutions containing 100 µg L^-1 of Hg²⁺ or MeHg⁺ showed no significant difference in the signal intensities. This demonstrates the capability of the reactor to convert both species into free Hg atoms. The total Hg in fish tissue determined by PMVG-AAS (0.73 ± 0.05 mg kg^-1) was in agreement with results obtained by a conventional method using a single-purpose mercury analyzer AMA-254 (0.67 ± 0.14 mg kg^-1). Additionally, approximately 10 mg of certified reference material (DORM-4; fish protein) was analyzed by the proposed PMVG based method, yielding 0.39 ± 0.05 mg kg^-1, corresponding perfectly to the certified value of 0.41 ± 0.04 mg kg^-1 Hg.

Although the results are still preliminary, the proposed method demonstrates a proof of concept of direct application of a PMVG reactor to solid samples. The developed system was able to volatilize Hg from a fish tissue and release it in the form of cold Hg vapor without the need for additional reagents or extra atomizer, and using a low power plasma reactor. The whole apparatus setup consisting of a PMVG reactor, its power supply source, the cold dryer and the amalgamator with temperature control, were low-cost and lab-made, with easy operation. In summary, this work presents the first successful use of PMVG directly to an untreated solid sample.

Acknowledgements

Financial support from the Czech Science Foundation (23-05974K), Institute of Analytical Chemistry (RVO: 68081715) and MŠMT ČR (LM2023039) are gratefully acknowledged.

Reference

[1] A. D'Ulivo, R.E. Sturgeon, Vapor Generation Techniques for Trace Element Analysis – Fundamental Aspects, Elsevier, Amsterdam, 2011.

Besides the economic relevance of the oil and gas industry, they are of high environmental concern, due to the generation of waste, such as oily sludge and drill cuttings. These wastes are of high complexity and contain potentially toxic organic compounds, metals, and non-metals that are of significant environmental concern ¹. However, the determination of metals and halogens such as Br and I in environmental samples is still an analytical challenge. Moreover, the determination of these elements by inductively coupled plasma mass spectrometry (ICP-MS), presents additional limitations due to plasma-generated interferences and matrix effects. Thus, sample preparation techniques such as alkaline extraction, pyrohydrolysis, and microwave induced combustion (MIC) have been efficiently applied for the further determination of Br and I ². However, alkaline extraction is an interesting alternative since it can be assisted by microwave and/or ultrasound, and it is simple, low-cost, and efficient. Normally, the alkaline extraction of halogens has been performed by tetramethylammonium hydroxide (TMAH) combined with heating ³. Although this extraction is not selective and various compounds from the matrix may be co-extracted, the resulting extract is significantly less complex than the original sample, making it particularly advantageous for ICP-MS analysis.

In light of the analytical challenges associated with the determination of Br and I and highly complex samples, we assume that an alkaline extraction procedure combined with the advantages of ICP-MS analysis can overcome the challenges inherent in quantifying these elements in wastes from the oil and gas industry. In this study, the simplicity and efficiency of TMAH extraction combined with the versatility and sensitivity of a quadrupole-based ICP-MS were used to overcome the challenges associated with the determination of Br and I in oily sludge and drill cuttings from oil and gas exploration wells. The parameters of the ICP-MS, which include plasma radiofrequency power and the nebulizer gas flow rate, were properly optimized. The sample preparation procedure using extraction with TMAH was optimized using the Doehlert design, evaluating the effects and interactions of the selected variables by the multiple response. The optimal extraction conditions were achieved using 100 mg of sample (drill cuttings or oily sludge), 500 µL of 25% (w/v) TMAH, an extraction temperature of 75 °C, and an extraction time of 4h. The accuracy of the proposed method was checked by the analysis of certified reference materials (CRMs) and by comparing the results with those obtained after pyrohydrolysis sample preparation. The determined Br and I concentrations in the CRMs were in good agreement with the certified values (t-test, 95% confidence level). In addition, the results obtained after pyrohydrolysis showed good agreement (97 to 107%) with the certified concentrations of the analytes, and no significant differences (t-test, 95% confidence level). The precision of the proposed method was evaluated by relative standard deviation (RSD), and good precision (RSD < 10 %) and low detection limits (0.01–0.03 mg kg⁻¹) were obtained, making this method suitable for the analysis of drill cuttings and oily sludge. A short-term stability study was performed to evaluate the signal drift and/or carbon deposition onto the cone´s surface. However, after 120 min of continuous sample introduction and under the optimized instrumental condition, the analytical signals did not significantly change, and no carbon deposits were observed.

The proposed method was applied to the determination of Br and I in 14 samples of oily sludge and 17 samples of drill cuttings from onshore and offshore oil and gas wells. In the analyzed drill cuttings, the concentration of Br ranged from 0.62 to 589 mg kg⁻¹, and I ranged from < 0.01 to 3.13 µg kg⁻¹. For oily sludge samples, the concentration of Br ranged from 0.64 to 5.69 mg kg⁻¹ and I from 0.55 to 2.69 mg kg⁻¹. Additionally, for drill cuttings, the obtained Br and I concentrations, their mineralogical composition, and their distribution across different sampling depths were evaluated by two-way hierarchical clustering analysis. These clusters indicate that the drill cuttings´ sampling depth influences the availability of certain elements. The proposed method offers a reliable approach for the determination of challenging elements (Br and I) in complex oily samples from the oil and gas industry.

Acknowledgments: The authors are thankful to CNPq, CAPES, the Federal Institute for Materials Research and Testing (BAM) and Alexander von Humboldt Foundation for their financial support

References

[1] E.E. Cordes et al., Front. Environ. Sci., 4 (2016) 58.

[2] F.S. Rondan et al., J. Food Compos. Anal. 66 (2018) 199–204.

[3] M.F. Mesko et al., J. Anal at Spectrom 31 (2016) 1243–1261.

The rapid evolution of portable spectroscopic technologies, particularly in the fields of near-infrared (NIR) and Raman spectroscopy, is revolutionizing molecular sensing by enabling on-site, real-time analysis across diverse environments. This plenary lecture will present how advancements in miniaturized instrumentation, combined with chemometric modeling and data-driven approaches, are breaking down traditional laboratory boundaries and empowering global solutions in applied analytical chemistry.

A special emphasis will be placed on portable NIR and Raman systems as versatile tools for tackling challenges in areas such as food quality control, pharmaceutical screening, environmental monitoring, and medical diagnostics. The lecture will highlight recent case studies demonstrating the successful deployment of handheld and field-deployable NIR and Raman devices, including applications in microplastic detection, counterfeit medicine identification, and molecular fingerprinting for disease diagnostics—particularly within the context of resource-limited settings.

The potential of these techniques to provide non-destructive, rapid, and reliable molecular information will be discussed, alongside current limitations and future directions, including the integration of quantum chemistry, artificial intelligence and multimodal spectroscopy.

This presentation underscores how portable NIR and Raman spectroscopy are driving global accessibility to high-quality analytical solutions, fostering scientific innovation beyond conventional laboratory infrastructures.

The agri-food sector is under increasing pressure to ensure product quality, safety, healthfulness and authenticity to fit the continuously changing consumer demands and regulatory requirements. Traditional analytical techniques, although accurate, are often time-consuming, require sample preparation, expertise personnel and are unsuitable for in-line and on-site monitoring. Alternatively, portable and low cots near-infrared spectrometers have emerged as a powerful, rapid, environmentally safe and non-destructive alternative that enables real-time and on-site analysis of a wide variety of food and agricultural products.

Such properties make Near Infrared Spectroscopy (NIR) a frontline tool for agri-food analysis, showing versatility across multiple product categories. Advanced multivariate calibration methods are commonly used to interpret the complex spectral data and extract meaningful chemical and physical insights.

We explore low cost portable NIRS devices with different operational settings, for on-site food quality and safety control. Application case studies include the quantification of nutritive parameters in food and the detection of food adulteration (e.g., milk frauds, olive oil adulteration). Furthermore, the integration of NIRS with other spectroscopic techniques (Data Fusion) or IoT platforms opens new avenues for smart quality monitoring in the agri-food chain, bridging the gap between analytical precision and operational efficiency.

Residual and applied stresses that act on polymer materials can result in their deformation, whitening and cracking. Understanding the distribution of these stresses is important for ensuring material quality. Raman micro-spectroscopy is a non-destructive technique that provides microscopic resolution, which has been used to analyze the stress distribution in semiconductor devices, ceramics and carbon materials. However, there are few examples of its application to polymer materials, mainly because of the difficulty in interpreting spectra associated with polymorphism. In this study, we investigated the feasibility and effectiveness of Raman spectroscopy to determine stress and strain distribution in polycarbonate (PC) molding. PC is a widely used industrial material that exhibits excellent transparency and impact resistance, however, can easily lead to cracks when exposed to solvents under stress.

Firstly, a 2 mm thick PC plate was subjected to four-point bending, and Raman spectral shifts near 1600 cm⁻¹ were analyzed. The results showed a linear relationship between the peak shift and the applied strain within the elastic range (~0.2 cm^-1/% strain), and non-linear behavior in the plastic region. This validated the measurement accuracy as 0.2% strain, corresponding to a stress detection limit of approx. 4 MPa. Next, three-dimensional mapping measurements were performed at different depths in the material. The results aligned with theoretical strain profiles, confirming the accuracy of the measurement in the thickness direction. Lastly, the effectiveness of the technique was demonstrated through analysis of solvent-induced cracks, created by applying acetone to a strained surface. The findings were as follows:

1. The maps revealed that the cracks extended to the depths of approximately 500 µm and that strain was sharply concentrated near the crack tips.

2. Finite element simulations replicated these experimental findings and enabled the quantification of strain that was undetectable by Raman method, by back-calculating from localized strain concentrations, exemplifying the synergy between the experiment and the simulation.

3. The application of polarized Raman micro-spectroscopy revealed that the solvent exposure relaxed the polymer chain orientation.

4. Interestingly, when the same plate was heated above the glass transition temperature, acetone did not induce cracks under strain, emphasizing the unique role of solvent action, such as the reduction of the intermolecular resistance.

In conclusion, Raman micro-spectroscopy enables precise, non-destructive three-dimensional visualization of stress and strain, and affords better understandings on polymer failures.

THz (low frequency) Raman spectroscopy extends the capabilities of conventional Raman spectroscopy, probing the range bellow 200 cm^-1. Signals in this region are mainly attributed to intermolecular vibrations of higher mass and phonon modes that are strongly correlated to the crystal structure of a material. They give information about the degree of crystallinity, molecular orientation and can be used to classify different allotropes and polymorphs. Therefore, THz Raman Spectroscopy is a powerful technique for obtaining both chemical and structural information in one measurement. Herein, we first introduce THz Raman spectroscopy as a fast and reliable technique for MOF-polymorph distinction, as shown with Fe-terephthalic acid based MOF examples. In addition, THz Raman can be used for in-situ phase transition analysis. Here, we probe the solvent-induced phase transitions in MOF systems and investigate the swelling behavior of MIL88 by THz Raman spectroscopy. Furthermore, we demonstrate the non-linear evolution of lattice modes as a function of temperature via low-frequency vibrational spectroscopy. We delve into the balance between conventional positive thermal expansion and phonon-driven negative thermal expansion in a mixed-linker solid solution of a frustrated metal-organic framework.

Digital microfluidics (DMF) describes a technique to manipulate micro- to nanoliter-sized droplets on a 2D-array of insulated and hydrophobic electrodes [1,2]. Research in this field has recently gained momentum due to the versatile sample handling of discrete droplets DMF offers, and the possibility to carry out chemical processes in an unrestricted and automated manner [3]. To monitor chemical processes, it is necessary to couple digital microfluidics with analytical techniques e.g. the hyphenation of DMF with mass spectroscopy [4] or surface-enhanced Raman spectroscopy [5]. However, coupling DMF with absorption-based spectroscopic techniques such as Infrared (IR), is a challenging task. With this work, we present the expansion of the current analytical toolkit for DMF, were we have now achieved the coupling of DMF with IR spectroscopy.

To enable the first DMF-IR coupling, we developed an IR transparent DMF-chip. The novel DMF chip used calcium fluoride as the substrate, enabling real-time IR imaging not only in the reflection but also in the transmission, which enhances the measurement sensitivity. To combine conductive and insulating materials with suitable IR absorption properties, a thin film sputtering-based fabrication method was developed. In order to minimize evaporation during long-term measurements, a remodelled electrode array with evaporation control functionality was designed.

A quantum cascade laser (QCL) for the mid-IR range was utilized to perform the experiments. The developed chip was evaluated by screening various IR-compatible solvents and analytes in a proof-of-concept study. The QCL-source allowed for fast imaging of entire droplets inside the chip. A long-term IR reaction monitoring of an imine synthesis reaction was performed to demonstrate the potential use of the DMF-IR device. The presented work provides an opportunity to study chemical processes in DMF more detailed using mid-IR spectroscopy and allows for real-time observation of droplets by in-situ IR imaging.

[1] M. G. Pollack, Appl. Phys. Lett., 2000, 77, 1725–1726.
[2] J. Lee, Sens. Actuators A, 2002, 95, 259–268.
[3] M. Abdelgawad, Adv. Mater., 2009, 21, 920–925.
[4] A. Das, J. Am. Chem. Soc., 2022, 144, 10353-10360.
[5] S. Fehse, Chem. Com., 2024, 60, 8252-8255.

Trace elements play an important role in biological processes and an association between the levels of trace elements and the presence of diseases has already been established. Thus, the understanding of the mechanisms of assimilation of trace elements may be indicative of the genesis or progression of the disease. Energy Dispersive X-ray Fluorescence technique (EDXRF) might be the innovative technique for screening analysis as it constitutes the ideal compromise for a non-destructive, of simple instrumentation and good sensitivity technique for the elements of interest. For these reasons, this technique has already been tested in research regarding to the characterization of tumour tissues. However, there is always a great impairment to statistically significant conclusions: the extremely reduced number of samples. The research here presented intends to overcome this obstacle by taking advantage of the vast repository of human tissue samples, fixed in formalin and embedded in paraffin, that is stored in Portuguese hospitals. However, there is a major disadvantage when using these samples, namely the type of substrate (formalin and/or paraffin), that increases the factor of greatest uncertainty in the quantification by EDXRF: the characterization of the dark matrix of the sample.

This presentation will demonstrate the methodologies implemented to overcome the constraints imposed by formalin and paraffin by revealing the results of several case studies

We present a self-mixing (SM) approach for methane detection in the mid-infrared (Mid-IR) region using a Quantum Cascade Laser (QCL) operating within the 7669–7679 nm spectral window. This range encompasses two strong methane absorption lines centered at 7673 nm and 7678 nm. Unlike conventional Mid-IR gas sensing architectures that require cooled photodetectors, the SM technique leverages the intrinsic sensitivity of the QCL to optical feedback, enabling photodetector-free operation and significantly reducing power and system complexity.

A mechanical chopper modulates the optical feedback by periodically interrupting the external cavity return beam, producing a square-wave modulation of the QCL terminal voltage, typically on the order of tens of millivolts. This signal is subsequently amplified and measured using a lock-in amplifier with extended integration time, enhancing detection sensitivity while suppressing broadband noise.

The SM signal is susceptible to spurious phase noise caused by environmental instabilities that perturb the optical path length, manifesting as non-absorption-related fluctuations in the QCL terminal voltage. To suppress these effects, we introduce mechanical vibration of the external cavity mirror up to several tens of micrometres. The frequency of the vibration is in the order of 100s Hz. This vibration produces multiple complete cycle phase shifts that, due to the lock-in amplifier’s filtering, are effectively averaged out, preserving the absorption-dependent signal component.

Experimental validation was conducted using two aluminum hollow waveguides of 7.5 cm and 25 cm lengths, provided by the University of Ulm. Methane concentrations of 1300 ppm and 477 ppm were tested. The system was calibrated for both path lengths, and measurements revealed a linear dependence between the terminal voltage swing and optical absorption, consistent with theoretical models for QCLs under weak to moderate optical feedback regimes.

The Limit of Detection (LOD) achieved with the 25 cm waveguide was 50 ppm at the 7673 nm line, with a calculated Limit of Quantitation (LOQ) of approximately 150 ppm. Owing to the generalizability of the SM mechanism, this sensing strategy can be extended to other gas species and Mid-IR spectral regions, considering the absorption coefficient of the targeted line(s) and provided that the laser operation under feedback remains unaffected.

In summary, we demonstrate the viability of a QCL-based SM sensor for low-cost, compact, and energy-efficient methane detection in the Mid-IR. Ongoing work aims to eliminate mechanical components through novel self-mixing architectures employing all-electronic or integrated optical modulation schemes.

Helicobacter pylori infection is a major cause of gastritis, peptic ulcers, and gastric cancer1,2, highlighting the need for accessible, rapid, and accurate diagnostic tools. Conventional methods such as endoscopy, biopsy, and culture provide high accuracy but are invasive, costly, and require specialized personnel, limiting their use in routine or decentralized healthcare settings. Non-invasive alternatives like stool antigen and serological tests are easier to perform but may lack the sensitivity and specificity required for reliable detection or fail to distinguish active from past infections. The ¹³C-urea breath test (UBT) is a well-established, non-invasive approach that leverages isotopic ratio measurements of exhaled ¹³CO₂/¹²CO₂ following ingestion of ¹³C-labeled urea. However, traditional implementations using FTIR3 or IRMS4,5 are typically bulky and impractical for point-of-care applications. In this work, we present a miniaturized mid-infrared (MIR) sensor platform that integrates two quantum cascade lasers (QCLs) emitting at 2310 cm⁻¹ and 2770 cm⁻¹ with substrate-integrated hollow waveguide (iHWG) gas cells of 3 cm and 9 cm lengths. This configuration enables precise, real-time detection of the ¹³CO₂/¹²CO₂ isotopic ratio in exhaled breath samples. The system achieves detection limits below 30 ppm for ¹³CO₂ using minimal sample volumes (~480 μL) with a linearity R² = 0.998 across clinically relevant isotopic ratios. This approach enhances isotopic selectivity and minimizes spectral interferences, while the miniaturized iHWGs significantly reduce the overall system footprint compared to traditional FTIR-based setups. These results demonstrate the feasibility of a portable, MIR-based breath analysis platform for H. pylori detection, paving the way for decentralized and potentially home-based diagnostics. Future work will focus on integrating it into user-friendly diagnostic devices.

Surface-enhanced Raman spectroscopy (SERS) enables the detection of vibrational spectra from highly diluted molecules adsorbed onto rough, plasmonically active coin metal surfaces. It offers sensitivities comparable to fluorescence spectroscopy while providing structural information at the same time. Despite its potential in pharmaceutical, environmental and quality control applications, SERS is rarely used in routine analysis, where mass spectrometry, UV/VIS spectroscopy, and fluorescence detection remain standard. This is largely due to challenges related to the stability, reproducibility, universality, and adsorption behavior of molecules on SERS substrates.

To address these limitations, we developed a pressure-stable microsensor that integrates a silver-based SERS substrate with a platinum electrode, enabling simultaneous electrochemical manipulation and real-time SERS detection—a technique known as spectroelectrochemistry. The incorporation of electrochemical control enhances signal intensity, activates the SERS substrate, regulates analyte adsorption, facilitates desorption, and provides additional structural insights through spectral modulation.

We demonstrate the performance of this sensor through applications in HPLC, including the separation and detection of classical SERS model dyes and B vitamins. These examples highlight the synergistic benefits of combining SERS with spectroelectrochemistry, marking a significant step toward the routine use of SERS in analytical chemistry.

This study presents the development of a novel closed-loop fiber-optic Raman probe system, designed to enhance and simplify current open-loop methods for fiber-based Raman spectroscopy. One aspect of this system is the integration of a computer-controlled liquid lens within the optical setup, enabling rapid autofocus capabilities. The design process involved evaluating various optical configurations against criteria, such as focal quality, working distance, and the numerical aperture (NA) for the signal collection. The chosen configuration achieved an image NA of 0.46, a working distance range of 7.6~10.3 mm, and an RMS radius of 49.5 μm. A unique three-channel probe was developed for the system. It includes a channel for the laser source to focus on the sample, and two additional channels for signal collection and analysis of which one is used for a photodiode detector and the other to perform Raman spectroscopy. The photodiode detector plays a crucial role in the closed-loop system by providing feedback for the autofocus mechanism. A new autofocus algorithm was designed to dynamically maintain the focal point on the sample, operating effectively within 50 ms, allowing handheld applications. The probe's performance was tested using polystyrene and polycarbonate sample. Results from these experiments, particularly when compared to control experiments with a fixed focal length, demonstrated the probe's ability to acquire accurate Raman spectra at various sample distances and speed. The study confirms that the 50 ms response time of the autofocus system is suitable for handheld operation, marking a significant advancement in fiber-optic Raman spectroscopy techniques.

Mid-infrared (mid-IR) spectroscopy is a powerful analytical technique, offering label-free, molecule-specific detection based on the fundamental vibrational transitions of chemical bonds. It is particularly well-suited for applications in the life sciences, including real-time monitoring of biochemical processes, breath analysis for medical diagnostics, and detection of biomarkers in complex biological matrices. A key technological enabler for such applications is the development of compact, stable, and tunable laser sources operating in the mid-IR range. Quantum Cascade Lasers (QCLs) have emerged as the leading technology in this domain due to their inherent spectral flexibility, high output power, and potential for integration into portable sensing systems.

In this contribution, we present the design, fabrication, and characterization of a series of quantum cascade lasers covering an exceptionally broad emission wavelength range from 3.8 μm to 14 μm. These devices were realized using bandstructure engineering tailored for different wavelength regimes, relying on InGaAs/AlInAs active regions grown on InP substrates using molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE). Waveguide designs were optimized to ensure good modal confinement, efficient heat dissipation, and robust single-facet emission across the spectral range. The lasers demonstrate continuous-wave (CW) operation with typical output powers in the range of tens to hundreds of milliwatts, depending on the emission wavelength and cavity configuration.

For spectroscopy applications requiring high spectral resolution and mode selectivity, we have developed single-mode QCLs based on distributed feedback (DFB) and coupled-cavity configurations. DFB QCLs with integrated gratings were fabricated for targeted wavelengths such as 5.2 μm and 11 μm, corresponding to strong absorption features of biologically relevant molecules including nitric oxide (NO), carbon monoxide (CO), and various volatile organic compounds (VOCs). The DFB structures exhibit robust single-mode emission with side mode suppression ratios (SMSRs) exceeding 30 dB and wavelength tuning capabilities via temperature and current control.

In addition to DFB devices, we have implemented coupled-cavity QCLs utilizing optical feedback from passive resonators and Vernier effect-based tuning mechanisms. These configurations provide enhanced spectral selectivity and allow for broader tuning ranges compared to conventional DFB lasers, enabling the interrogation of multiple analytes or overlapping spectral features in complex biological samples.

All devices were comprehensively characterized using spectroscopic and electrical techniques, including high-resolution Fourier-transform infrared (FTIR) spectroscopy, beam profiling, and power-current-voltage (P-I-V) measurements. Long-term stability and reproducibility were also assessed to ensure suitability for integration into field-deployable spectroscopic instruments.

The presented results demonstrate the maturity and versatility of QCL technology as a foundation for mid-IR spectroscopic tools tailored for life science applications. The combination of broad wavelength coverage, single-mode operation, and high output power opens the door to advanced sensing platforms for healthcare, environmental monitoring, and biochemical diagnostics.

The growing demand for monitoring specific molecules in environmental, health, and security applications has created a need for inexpensive and power-efficient light sources. In particular, the mid-infrared (MIR) wavelength ranges from 3 µm to 9 μm is of high interest for gas-sensing. Many trace gases ubiquitous to industrial sites have their strongest absorption bands in this region, e.g. carbon dioxide, nitric oxide, water, and various important hydrocarbons. They show absorption strengths that are several orders of magnitude higher than those in other spectral areas.

Aiming at providing reliable broadband and cost-effective alternatives to standard optical gas analysis, nanoplus has developed light-emitting diodes (LEDs) in the MIR. The novel substrate-side-emitting devices rely on the innovative nanoplus technology for distributed feedback (DFB) interband cascade lasers (ICL) and are available at customized wavelengths between 2800 nm and 6500 nm. They display higher wall-plug efficiencies and maximum output powers than previous MIR LEDs, operating in continuous-wave (cw) at room temperature.

nanoplus has specialized in designing DFB lasers for high-precision gas sensing in industry and research. Based on a ridge waveguide structure, which is independent of the material system, nanoplus designs CW DFB lasers at any wavelength between 760 nm and 14 µm. The nanoplus flagship product is a DFB ICL with target wavelengths from 2800 nm to 6500 nm and an extremely narrow linewidth of below 3 MHz. At top-rated wavelengths, the laser shows output powers above 15 mW and is hence perfectly suitable for highly sensitive gas detection. In this talk we will present various applications which utilize DFB ICLs or MIR LEDs and give a general overview of this technology including latest results from interband cascade photodiodes (PD) and LED-arrays in the MIR or up to 10 µm and some of our R&D projects.

The development of novel energy materials, such as organic photovoltaics, next-generation batteries, and hydrogen storage media, is pivotal for enabling sustainable energy solutions. These materials often exhibit unique nanoscale features and highly localized functional properties due to their increased surface-to-volume ratios, requiring advanced characterization techniques to fully understand and optimize their performance. Nanoscale infrared microscopy offers exceptional spatial resolution combined with broadband infrared spectroscopy capabilities, making it a powerful tool for the comprehensive investigation of these materials. In applications ranging from solid-state and metal-air batteries to ion-exchange membranes, nanoscale infrared methods enable detailed chemical mapping and correlation of morphology with electrochemical functionality. Similarly, in organic and perovskite-based photovoltaics, nanoscale infrared techniques reveal critical insights into local structure–property relationships, morphology, and degradation mechanisms—ultimately aiding in the enhancement of power conversion efficiency and long-term stability. By bridging optical, electrical, and mechanical modalities in one technique, nanoscale infrared microscopy is transforming how researchers design and optimize next-generation energy materials for both academic research and industrial applications. This presentation highlights recent applications enabled by infrared nanoscale technology.

Spectrally resolved sensing gains increasing interest for deriving analytical information from a sample in contact-free and fast manner. Regarding spatially resolved information, this has evolved towards hyper spectral imaging (for low resolution imaging). Alternatively, miniaturizing and parallelizing spectrally resolving systems remains a challenge, especially in the context of mobile applications. In a recent work, we have introduced an approach based on planar micro-optics technologies. It is based on stretched grating spectrometers that are arranged in a two-dimensional array configuration [1]. The array configuration features the option to increase the system’s number of channels without increasing the complexity of the optical system.

This approach has been advanced towards spectral resolution in the 3 nm range for approximately 30 simultaneous measurements in the visible spectral range (400..800 nm), and has been combined with a fiber based light delivery for distributed sensing applications. Therefore, a dedicated optics design has been developed, which combines (i) an effective medium grating to reach polarization independent diffraction efficiency across the full spectral range, (ii) an array of identical micro-optical channels with an aperture in the 1.5 mm range to reach the required spectral resolution, and (iii) sufficient lateral imaging capability of each channel to enable laterally resolved detection along the slit. The latter enables to read out three fibers per spectrometer channel. The number of channels depends on the image sensor used: For the 9 mm diagonal sensor Sony IMX178 we manage to arrange 13 channels, whilst each channel analyzes the spectra from 3 fibers.

To set up this kind of system, refractive elements have been prepared by wafer-level polymer-on-glass replication, including the preparation of achromatic lenslets. The transmission grating fabricated by electron lithography has been arranged inside a micro-optical prism-grating-prism configuration. The optical elements have been arranged by passive integration on chip scale; fiber array and image sensor have been mounted under active alignment to ensure light throughput as well as sharpness of the image. In total, the optical system features a length of 18 mm only, resulting in volume of less than 8 ml.

The presentation will motivate and illustrate optical system design, the components being used as well as initial characterization results.

^[1] N. Danz, B. Höfer et al., Optics Express 27 (2019) 5719

Bridging the gap between chemical specificity and spatial resolution, the optical photothermal mid-infrared microscope (OPTIR) provides a new path for materials and life science research. The first commercial OPTIR instrument has been developed to collect infrared spectra and acquire images in point-based scan mode with dwell times down to a 1 ms per pixel. OPTIR images have sub-micron lateral resolution and are less impacted by anomalous scattering phenomena than direct quantum cascade laser (QCL)-based or Fourier transform infrared (FTIR) spectroscopic imaging [1,2]. Recently wide-field OPTIR techniques were developed for capturing images of large areas (20 – 100 µm in diameter) at submicron spatial resolution in a few hundreds of milliseconds [2]. An innovative implementation will be showcased, motivated by these advancements to enhance the field of view to larger than 200 µm with a high-power free-electron laser (FEL). The wide-field setup was first implemented in a time-gate manner with QCL excitation as pump source (50 KHz repetition rate), LED as a probe source (50 KHz) and 24 MP CMOS camera (1 - 400 Hz frame rate) as a detector using a waveform generator as the trigger source. The CMOS camera was used to capture images while the infrared beam was on (hot) and off (cold). The difference between hot and cold image generates photothermal contrast. Using a 40×, 0.6 NA objective in a field of about 40×40 µm², the system demonstrated a spatial resolution of less than 1.6 µm. Moreover, IR spectra can be reconstructed by a series of images at 5 cm^-1 wavenumber intervals. Additionally, the QCL was replaced with the FEL, and hyperspectral images were obtained from mouse brain tissue and THP-1 cells. The FEL-based setup imaged an area over 19 times larger than QCL based. The FEL-based wide-field detection with a high-speed CMOS would facilitate widefield image acquisition with improved time resolution. This advancement could significantly benefit various fields, including neuroscience, by enabling researchers to explore the dynamics of chemical composition in functional brain tissues from large areas and to map neurotransmitters and other important biomolecules.

Acknowledgement: This work is funded within the Leibniz Center for Photonics in Infectious Research (LPI) by BMBF.

[1] C. Krafft, R. Salzer, S. Seitz, C. Ern, M. Schieker. Differentiation of individual human mesenchymal stem cells probed by FTIR microscopic imaging. Cytometry A, 2005, 64A, 53-61

[2] Teng, Xinyan, et al. "Mid-infrared Photothermal Imaging: Instrument and Life Science Applications." Analytical Chemistry 96.20 (2024): 7895-7906..

Climate change, driven by global warming and unstable weather patterns, is creating critical challenges for modern food production. One significant concern is the growing prevalence of plant pathogens in cereal crops, particularly species such as Fusarium graminearum and Fusarium culmorum. These fungi produce harmful secondary metabolites known as mycotoxins, which pose a serious threat to global food safety. Consequently, there is a growing need for analytical tools that enable rapid, sustainable, and on-site detection and monitoring of such contaminants.

This presentation introduces innovative spectroscopic technologies designed for real-time mycotoxin detection throughout the food supply chain. A portable IR-ATR device has been developed for quick, on-site screening at critical control points, such as farms, transport stages, and storage facilities. In parallel, a high-precision laser-based analyzer system offers confirmatory analysis at goods reception points and within laboratory settings. The effectiveness and reliability of these systems for detecting mycotoxins will be demonstrated, highlighting their value in food safety monitoring. Furthermore, the presentation explores the potential to extend these technologies to pesticide detection, offering a promising avenue for comprehensive quality assurance in the agri-food sector.

Acknowledgment: This work was supported by the EU Horizon 2020 project PHOTONFOOD [#101016444] which is part of the PHOTONICS PUBLIC PRIVATE PARTNERSHIP and Financial support programmes for female researchers, Office for Gender Equality, Ulm University.

Analytical spectroscopy plays a leading role in the characterization of nanomaterials. An exhaustive (nano)materials characterization and the appropriate choice of methodologies for nano-toxicological risk assessment promise nowadays a reliable and accurate data output to guarantee their safe application in real-life products. In this communication, analytical spectroscopy was used to guide and support the production of human-safe polymer composites modified with copper particles, for food packaging applications.

Reducing agrifood waste has become an important goal, considering that up to 50% of total production is lost due to contamination by harmful microorganisms. In this context, controlling the interface between food products and the external environment can be a powerful tool to prevent waste. The aim of this study was to produce a bio-based and biodegradable food packaging material loaded with copper particles, which act as an antimicrobial reservoir.

A green one-pot approach was used to synthesize copper particles using poly(N-vinylpyrrolidone) (PVP) as a capping agent (Cu@PVP), preventing aggregation through steric hindrance and eliminating the need for an inert atmosphere [1]. The influence of PVP and reductant concentrations, as well as reaction time, on the oxidation state of copper, kinetics, and particle size was investigated by varying each of these parameters individually [2]. Optimal conditions were identified to obtain an average particle diameter above 200 nm, while minimizing reagent and time consumption, to prevent nano-cytotoxicity effects. After a purification step, the Cu@PVP particles were suspended in ethanol and embedded in a chitosan (CS) polymeric matrix.

Composite films were obtained by solvent casting [3]. The polymer solution concentration was adjusted to maintain good rheological properties even in the presence of inorganic particles. Torsional rheology and water uptake measurements were performed to assess the mechanical behavior of the self-standing films obtained after solvent evaporation. The antimicrobial capabilities were demonstrated by ionic Cu²⁺ release kinetics, and in vitro by growth inhibition of three different model fungi responsible for agrifood spoilage.

A thoughtful spectroscopic characterization was performed on Cu@PVP particles and composite films, by UV-Vis, Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopies. Both films and particles have been also characterized morphologically by transmission (TEM), atomic force (AFM), and scanning electron (SEM) microscopies.

This innovative material could be used for the production of biodegradable bags and envelopes destined to the storage of fruits and vegetables, extending the shelf-life of these horticultural products.

References:

[1] M.C. Sportelli et al., Chem. Eur. J., 2023, 29, e202203510. DOI: 10.1002/chem.202203510.

[2] D. d’Agostino et al., Food Chem., 2025, 464, 141823. DOI: 10.1016/j.foodchem.2024.141823.

[3] E. Kukushkina et al., IJMS, 2022, 23, 15818. DOI: 10.3390/ijms232415818.

Arsenic speciation is essential in environmental and toxicological studies due to the distinct toxicity and bioavailability of its chemical forms. High-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is a widely accepted technique for this purpose, offering high sensitivity and selectivity. However, its analytical performance is critically dependent on both the chromatographic separation conditions and the efficiency of the sample introduction system, which influences analyte transport, signal stability, and matrix effects.

In this work, an HPLC-ICP-MS method was developed and optimized through the integration of two advanced strategies: the use of the high-temperature Torch Integrated Sample Introduction System (hTISIS) as sample introduction system, and the Single Injection Calibration Approach (SICA). The hTISIS operated at the optimized temperature of 150 °C and ultra-low liquid flow rates (45 µL min⁻¹), achieving nearly complete solvent evaporation in the chamber, reduced memory effects, and enhanced analyte transport efficiency. Compared to a conventional double-pass spray chamber, hTISIS improved sensitivity by an order of magnitude, achieving limits of detection as low as 0.09 µg kg⁻¹ versus 0.47 µg kg⁻¹ with the conventional one. Its compatibility with microflow conditions supports more sustainable and cost-effective analytical workflows.

Quantification was carried out using SICA which generated the calibration using a single standard injection. This approach shortened calibration time and reagent consumption by up to 75% compared to conventional multi-point calibration, while maintaining excellent linearity (R² > 0.999) and precision (RSD < 10%). The method was validated using two certified reference materials (Frozen Human Urine SRM 2669 with two different concentration levels and Apple Juice SRM 3035), achieving excellent accuracy, and providing recoveries ranging from 92 to 110%. Chromatographic separation was performed on a PRP-X100 anion-exchange column (5 µm, 150 × 2.1 mm) under gradient elution with 60 mmol L⁻¹ ammonium bicarbonate (pH 8.7) and 5% methanol, allowing baseline resolution of arsenite (As³⁺), arsenate (As⁺⁵), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB) within 12 minutes.

The method was successfully applied to the analysis of commercial fruit juice samples, where trace levels of arsenic species were detected, with As⁵⁺ being the predominant species. These results were consistent with previously reported data, being inorganic arsenic concentrations in juices ranging from 10 to 80 µg kg⁻¹, and confirmed the method applicability for routine food safety monitoring.

The rise of biodegradable polymers as sustainable alternatives to conventional plastics is currently posing significant challenges, particularly regarding the waste management of bioplastic products and assessing the actual environmental benefits of this progressive substitution. It is well established that bioplastics degrade poorly under anaerobic conditions, often resulting in the persistence of unwanted residues in the digestate, which may subsequently lead to their release into the environment. In this work, hyperspectral imaging (HSI) in the short-wave infrared range (SWIR: 1000–2500 nm) was explored as a fast and non-destructive technique for the monitoring of micro-bioplastics (MBPs) presence in digestate. For this purpose, four different commercial bioplastic products, a cup, plate, coffee capsule and shopper, were analysed by HSI before and after 14 and 30 days of thermophilic anaerobic digestion to evaluate the possibility of their identification in digestate at different stages of degradation. The analyses were carried out at the RawMaLab (Raw Materials Laboratory) at Sapienza University of Rome (Rome, Italy) using the SisuCHEMA XL^TM chemical imaging workstation (Specim, Spectral Imaging Ltd, Finland). Hyperspectral images were acquired using two different spatial resolutions (150 µm/pixel and 30 µm/pixel). The investigated samples were subdivided into a calibration and a validation dataset. The calibration dataset consisted of MBPs obtained by mechanically powdering the four different bioplastic products, which were further divided into two different size fractions (1 – 0.5 mm and < 0.5 mm), therefore obtaining 8 different samples (one for each bioplastic type and size fraction). The samples were manually placed onto individual cellulose filters, previously covered with a thin layer of digestate and dried at room temperature, to simulate the combination between the two materials (bioplastics and digestate). The dataset was acquired using the two spatial resolutions obtaining in total sixteen hypercubes. The validation dataset consisted of the final digestates coming from the anaerobic biodegradation of the four products after 14 and 30 days, that were sieved at 0.84 mm to remove larger undegraded bioplastic particles, then sampled and spread on cellulose filters and dried at room temperature. The resulting eight filters (one for each bioplastic type and biodegradation stage) were examined for the presence of MBPs which could not be separated mechanically. The filters were acquired using the two spatial resolutions, obtaining also for this dataset a total of sixteen hypercubes. Chemometric techniques were applied on the acquired hypercubes for data processing using the MATLAB^® environment (R2024a, The Mathworks, Inc., USA). On calibration dataset exploratory data analysis was performed using Principal Component Analysis (PCA) to evaluate spectral variability and to identify the best preprocessing algorithms. The PCA results revealed differences in the average reflectance spectra between MBPs and the digestate matrix. Following this exploratory analysis, a 5-classes (four different MBPs classes and one digestate matrix) Hierarchical Partial Least Squares-Discriminant Analysis (Hi-PLS-DA) model was developed for automatic classification purposes. The classification model was applied to the validation dataset demonstrating a robust discrimination between the four different MBP types and the digestate matrix. This approach provides a promising strategy for the real-time identification and quantification of MBP particles in complex environments. The research demonstrates the potential of HSI, combined with advanced chemometric data analysis, as an effective tool for fast, non-invasive identification and classification of different bioplastics. The ability to detect and classify MBPs in digestate offers valuable insights into the monitoring of the anaerobic digestion process and the quality of the final products, which can serve as a first step for assessing potential contamination and associated toxicity effects.

In recent years, insects have garnered significant attention as a more sustainable protein source, offering advantages over traditional animal-based proteins. In addition to being protein-rich, insects provide good nutritional value, including bioactive compounds such as vitamins, minerals, and long-chain polyunsaturated fatty acids. However, they can also bioaccumulate toxic elements from the environment. Since the consumption of insects constitutes an interesting sustainable source of essential elements to the diet, but also a source of toxic elements, it is important from a food quality perspective, to evaluate the bioaccessible fraction for each relevant element, defined as the fraction that is released from the food matrix into the gastrointestinal tract and has the potential to be absorbed and transformed into bioactive species. In this regard, in vitro approaches are good alternatives to imitate what naturally occurs during the human digestive process. In this study, aluminium, copper, iron, lead, manganese, and zinc were evaluated. Wild insect samples were collected in January 2024 and characterized by an entomologist as Chromacris speciosa, Diloboderus abderus, and Gryllus assimilis. Afterwards, samples were lyophilized and then triturated and homogenized by means of a ball mill. The gastric solution consisted of 3 g L^-1 pepsin in 12 mol L^-1 HCl, pH 1.3, while the intestinal solution was 2 g L^-1 bile salts and 5 g L^-1 pancreatin in 0.2 mol L^-1 NaOH, pH 6.8. A portion of 0.5 g of dried sample was placed into a 25 mL flask with 5.0 mL of gastric solution and shaken in vortex for 2 min. The mixture was then kept in a water bath with orbital shaking at 37 °C for 2 h. Prior to intestinal digestion, the pH of the previously obtained solution was adjusted to 6.8. Then, 5.0 mL of intestinal solution were added, the mixture was shaken in vortex for 2 min and incubated again at 37 °C for 2 h. Finally, the mixture was centrifuged at 28,000 g for 30 min and the supernatant separated from the residue and used for bioaccessible fraction determination. The bioaccessible fraction (BF) was calculated as: BF (%) = (RF/TC) × 100, where RF was the released fraction of the element and TC was the total concentration of the element. To evaluate the accuracy of the assay, the corresponding mass balance was performed. For the determination of total concentrations in samples and residues a microwave-assisted acid digestion was carried out. Briefly, 0.5 g of sample was accurately weighted into each reaction vessel and 10.0 mL of 4.5 mol L^-1 HNO₃ was added. The program consisted of a 15 min ramp time until 200 °C, holding for 15 min, and then cooling to room temperature. After mineralization samples were filled up to 10.0 mL with ultrapure water. Analytical determinations were performed by microwave induced plasma optical emission spectrometry (MIP OES) using an Agilent 4210 spectrometer with an inert One Neb nebulizer with a double-pass glass cyclonic spray chamber system and a standard torch. The spectrometer used an online nitrogen generator. Operational conditions such as pump speed, nitrogen flow, and viewing position were thoroughly optimized for each element. The plasma gas flow was fixed at 20 L min^-1 and the auxiliary gas flow at 1.5 L min^-1. The following operational settings were applied: uptake time of 70 s, plasma stabilization time with sample aspiration of 15 s, read time of 3 s (in triplicate), wash time of 20 s, wavelengths 396.152 nm (Al)/ 324.754 nm (Cu)/ 371.993 nm (Fe)/ 403.076 nm (Mn)/ 405.781 nm (Pb)/ 213.857 nm (Zn). Automatic background correction was used. The obtained bioaccessible fractions agreed with previous results reported by our research group in similar European species. MIP OES turned out to be a very efficient and green alternative for the sequential evaluation of essential elements for bioaccessibility assays, used for the first time for this purpose here in this work, to increase the knowledge about the nutritional potential of these sustainable food sources.

Nutrient-solubilizing microorganisms have been increasingly investigated for the development of bio-based agricultural inputs due to their production of metabolites such as organic acids, which are known to solubilize phosphate rock. Citric, oxalic, and malic acids are examples of organic acids produced by microorganisms that play a critical role in nutrient dissolution. In this context, this biotechnological strategy can be explored as an alternative method to solubilize analytes during the sample preparation step for elemental determination by plasma-based techniques. In this study, we evaluated the performance of organic acids (citric, oxalic, and malic) produced by Aspergillus niger under solid-state fermentation in sugarcane bagasse, aiming to solubilize nutrients and contaminants elements from various sample types during sample preparation for elemental determination by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP OES). The fermentation and acid extraction conditions were based on the methodology described by Klaic et al. (2020)¹, which optimized the production of organic acids by Aspergillus niger (strain 763). Certified reference material of tomato leaves (SRM 1573a, NIST, USA) and a reference material of mineral supplement (RM-Agro E2001a, Embrapa Pecuária Sudeste, Brazil), were submitted to sample preparation using the organic acid medium diluted with deionized water. The extractions were performed using three approaches: extraction block (120 min at 90 °C), ultrasound-assisted extraction (60 min at 50 °C), and microwave-assisted extraction (up to 120 °C). Recoveries for tomato leaves ranged from 82–86% for K, 69–81% for Mg, 62–72% for Mn, 89–102% for Na, and 50–60% for P (determined by ICP-OES). For the mineral supplement, recoveries ranged from 96–97% for As and 79–80% for Cd (determined by ICP-MS). According to the t-test, no statistically significant difference was observed between the concentrations obtained using the digestion block and ultrasound-assisted extraction methods. Additional studies are underway to evaluate other matrices, acid concentrations, and extraction temperatures. The results indicate that the organic acid medium produced by microorganisms shows strong potential for solubilizing nutrient and contaminant elements. This approach is compatible with plasma-based analytical techniques and represents a promising and sustainable alternative for sample preparation.

Ensuring safe drinking water requires effective disinfection, but the interaction of chemical disinfectants (e.g., chlorine) with organic matter leads to the formation of disinfection byproducts (DBPs), many of which pose environmental and health risks [1,2]. Monitoring these contaminants in real-time remains a major challenge due to the complexity of aqueous matrices and the need for highly sensitive innovative detection methods for on-site monitoring. To address these concerns, this study presents two portable mid-infrared (mid-IR) sensing systems, providing data for the simultaneous detection and quantification of DBPs, combining both experimental and computational approaches. The portable compact devices - each approximately the size of a shoebox - facilitate long-term, detailed monitoring campaigns at selected pilot sites.

The sensing systems use attenuated total reflection infrared (ATR-IR) spectroscopy, utilizing broadband light sources, providing an efficient method for in situ DBP detection This innovative sensor technology combines advanced photonic detection schemes with automated sampling enabling continuous on-site monitoring of contaminants at critical points such as water distribution systems, reservoirs, and water treatment plants. The active sensing interface is based on a fiberoptic waveguide coated with a polymeric molecular recognition membrane preconcentrating the analytes of interest from the water matrix [3, 4]. The evanescent field generated in an active optical transducer (silver halide fiber) penetrates a few micrometers into the sample, allowing real-time interaction and analysis without extensive sample preparation. This approach enables online monitoring of dissolved pollutants, eliminating the need for costly and time-consuming laboratory procedures. Linear calibration functions of simultaneously detected DBPs revealed limits of detection at low ppb concentration levels [5].

The developed mid-IR spectroscopic sensing systems were deployed in March 2025 at a pilot site in Coimbra, for real-time water quality monitoring. These systems allowed for the rapid on-site detection, differentiation, and quantification of 15 DBPs in water at regulatory levels including trihalomethanes, haloacetic acids, haloacetonitriles, oxyhalide compounds and haloketones [3].

To enhance spectral interpretation, as well as the accuracy and reliability of DBP detection, the experimental IR spectra were calibrated using computational methods of quantum chemistry, contributing to more effective water quality management strategies. The characteristic IR signatures of 28 critical DBPs [1] in polar solvent (water) and in hydrophobic solvent (toluene) were computed theoretically. Experimental spectra obtained from the IR sensing devices were validated against those from a benchtop spectrometer and compared with theoretical data in the full mid-IR range (4000-600 cm⁻¹). This allowed us to confirm the identities of several DBPs detected during field experiments in the mid-IR fingerprint range (1800-830 cm⁻¹). Selected results from this collection will be presented and discussed at the meeting.

Funding

This work is part of the project H2OforAll [3], funded by the European Union, Grant Agreement GA101081963, and is also supported by Portugal-Germany Bilateral Cooperation 2024, project No. 2024.07770.CBM. The Research Centre CERES (http://www.uc.pt/ceres/) is supported by the Portuguese Science Foundation, projects UIDB/EQU/00102/2020, DOI: 10.54499/UIDB/00102/2020 and UIDP/EQU/00102/2020, DOI: 10.54499/UIDP/00102/2020 (National Funds).

References

1. I. Kalita et al. ACS EST Water 2024, 4, 1564-1578. DOI: 10.1021/acsestwater.3c00664

2. M. I. Roque et al. Water 2023, 15, 1724. DOI: 10.3390/w15091724

3. H2OforAll: “Innovative Integrated Tools and Technologies to Protect and Treat Drinking Water from Disinfection Byproducts”. DOI: 10.3030/101081963.

4. R. Lu et al. Angew. Chem. Int. Ed. 2013, 52, 2265. DOI: 10.1002/anie.201209256

5. R. Lu et al. Sci. Rep. 2013, 3, 2525. DOI: 10.1038/srep02525

Due to their presence in everyday products and accumulation in the biosphere, microplastics have become an ever-growing concern for human health. To enable a comprehensive characterization of microplastics, which are formed as by- or degradation product of plastics, typically several different analytical methods are necessary to assess their particle size and distribution as well as their molecular/elemental composition. While a combination of Laser Ablation-ICP-MS (LA-ICP-MS) and Single Particle-ICP-MS is able to evaluate the majority of these properties1, 2, it typically requires knowledge about the polymer type beforehand to accurately determine the occurring trace element levels. Since the Inductively Coupled Plasma is a hard ionization source, molecular information is not available and thus a preceding analysis with techniques such as Fourier Transform-Infrared Spectroscopy or Raman Spectroscopy is required.

However, continued development of instrument technologies have led to significant improvements in the time resolution for LA-ICP-MS setups, enabling the investigation of the signal response of individual laser shots, the so-called Single Pulse Response (SPR). Investigations of the SPR of gelatine by van Helden et al.3, 4 showed that some elements (e.g., C, Zn, and Hg) exhibit a bimodal SPR profile, which they explained by separation of the ablated material into a particulate and a gaseous phase.

Considering that synthetic polymers (and therefore microplastics) can contain varying amounts of carbon (and oxygen, nitrogen, etc.), we assume that the ratio of particulate and gaseous phase is different for each polymer, which would allow for polymer classification based on the SPR of carbon. For this, we investigate the two-phase sample transport resulting from the ablation of polyimide (PI), poly(methyl methacrylate) (PMMA), polyvinylpyrrolidone (PVP), polysulfone (PSU), and polyvinyl chloride (PVC). We discuss the impact of laser ablation parameters (laser energy, spot size, ablation cell parameters) on the SPR profile and the classification accuracy and how the addition of heteroatoms, e.g., sulfur for PSU and chlorine for PVC, can influence the performance.

Ultimately, we intend to employ this classification approach on real-life samples containing different polymers in order to avoid using multiple instruments and techniques, therefore providing a complete solution for microplastics characterization when trying to quantify trace metals.

(1) Brunnbauer, L.; Kronlachner, L.; Foisner, E.; Limbeck, A. Novel calibration approach for particle size analysis of microplastics by laser ablation single particle-ICP-MS. Journal of Analytical Atomic Spectrometry 2025, 40 (3), 753-761, 10.1039/D4JA00351A. DOI: https://doi.org/10.1039/D4JA00351A.

(2) Van Acker, T.; Rua-Ibarz, A.; Vanhaecke, F.; Bolea-Fernandez, E. Laser Ablation for Nondestructive Sampling of Microplastics in Single-Particle ICP-Mass Spectrometry. Analytical Chemistry 2023, 95 (50), 18579-18586. DOI: https://doi.org/10.1021/acs.analchem.3c04473.

(3) Van Helden, T.; Mervič, K.; Nemet, I.; van Elteren, J. T.; Vanhaecke, F.; Rončević, S.; Šala, M.; Van Acker, T. Evaluation of two-phase sample transport upon ablation of gelatin as a proxy for soft biological matrices using nanosecond laser ablation – inductively coupled plasma – mass spectrometry. Analytica Chimica Acta 2024, 1287, 342089. DOI: https://doi.org/10.1016/j.aca.2023.342089.

(4) van Elteren, J. T.; Van Helden, T.; Metarapi, D.; Van Acker, T.; Mervič, K.; Šala, M.; Vanhaecke, F. Predicting image quality degradation as a result of two-phase sample transport in LA-ICP-TOFMS mapping of carbon-based materials. Journal of Analytical Atomic Spectrometry 2025, 40 (2), 520-528. DOI: https://doi.org/10.1039/D4JA00288A.

The contamination of aquatic environments by pharmaceuticals is a critical global concern, not only due to their persistence, bioaccumulation, and adverse effects on ecosystems and public health, but also because of their role in accelerating bacterial resistance affecting public health. Tackling this issue effectively requires a preventive approach based on continuous and reliable environmental monitoring. However, conventional detection and quantification methods often fall short in practical applications due to their complexity, high cost, and limited scalability.

A promising alternative is surface-enhanced infrared absorption spectroscopy (SEIRA), a technique capable of enhancing vibrational signals and enabling the detection of analytes at trace levels. Traditionally, SEIRA uses plasmonic nanoparticles of gold (Au) or silver (Ag) to amplify signals. However, silver-based semiconductor nanocrystals, such as silver chalcogenides, have recently shown great potential as alternative amplifiers due to their unique surface properties and interaction mechanisms.

In this study, silver selenide quantum dots (Ag₂Se QDs) were evaluated as SEIRA signal amplifiers for the detection of pharmaceuticals, namely the antidepressant venlafaxine. These nanomaterials have the potential to promote strong local field enhancements and interact with pharmaceutical molecules through electrostatic forces or surface adsorption interactions that can localize vibrational modes and lead to significant signal amplification.

Ag2Se QDs were prepared in aqueous medium, using glutathione (GSH) and ascorbic acid as the stabilizing and reducing agent, respectively. These QDs were purified to reduce the spectral interference from free stabilizer bonds, ensuring a clearer assessment of analyte – QD interactions. The SEIRA experimental strategy focused on optimizing sample preparation and deposition methods onto the FTIR crystal, comparing two approaches: i) deposition of the QDs and analytes mixture, where QDs and analytes were applied simultaneously; and ii) layered deposition, where QDs were first deposited and dried before analyte application. Preliminary results showed that specific IR signal regions of venlafaxine could be enhanced by up to 32 times compared to the pharmaceutical alone, enabling its detection at concentrations in the µg/mL range.

The proposed SEIRA-based analysis setup built on Ag-based QDs can be an accessible and practical experimental tool for the detection of pharmaceuticals. Thus, this work contributes to the development of efficient and environmentally responsible tools for monitoring organic microcontaminants in water.

The authors acknowledge financial support from UID Centro de Estudos do Ambiente e Mar (CESAM) – LA/P/0094/2020 and the project NanoSEIRA (COMPETE2030-FEDER-00866600); as well as the Erasmus+ program and the DAAD (German Academic Exchange Service) for enabling the research exchange.

Given the growing global demand for cannabis, both for recreational and medicinal purposes, it is critical to establish and adhere to strict regulatory standards, that include sustainable agricultural practices, continuous monitoring of contaminants, and the use of advanced testing techniques.

Cannabis plants have the ability to accumulate metals from atmospheric pollution, soil, or contaminated irrigation water. Toxic heavy metals such as Cd, Pb, and Hg can appear in cannabis products through plant bioaccumulation, cross-contamination during processing, or post-processing adulteration. Exposure to these metals via ingestion or inhalation poses long-term toxicological risks, making their monitoring a priority in quality control protocols.

Cannabis testing is governed by a complex regulatory framework, posing challenges for analytical laboratories that must develop methods compliant with varying regional and national regulatory limits.

Currently, for the analysis of heavy metals in cannabis flowers and derived products, international regulatory agencies recommend inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS). These techniques are widely used due to their ability to analyse multiple elements with high sensitivity, speed, robustness, and broad dynamic range for both major and trace elements. One of their main disadvantages is the high cost, both in terms of initial investment and operation, which can limit accessibility, particularly for analytical laboratories in developing countries.

Microwave plasma atomic emission spectrometry (MP-AES) emerges as a promising alternative due to its accurate results, ease of operation, and environmentally friendly design, as it uses air instead of argon, significantly reducing operational costs.

This study presents the development, optimization, and validation of alternative analytical methods for the determination of Cd, Pb, and Hg in cannabis flowers using MP-AES as the detection technique. For Hg determination, a cold vapor generation system was employed to produce elemental mercury, which was subsequently analyzed by MP-AES.

Samples were obtained from licensed recreational cannabis dispensaries. In the laboratory, the samples were dried, milled, and stored under controlled conditions until analysis. A 0.5 g aliquot was placed into a digestion vessel, followed by the addition of 10.0 mL of 4.7 mol L⁻¹ HNO₃. The vessels were then subjected to microwave-assisted acid digestion. The same procedures were applied to reagent blanks and certified reference materials.

Elemental analysis was performed using an Agilent 4210 MP-AES spectrometer equipped with a multimode spray chamber for vapor generation, a double-pass glass cyclonic spray chamber, and a standard torch.

A matrix effect resulting in signal suppression was observed for Cd and Pb. To mitigate this, the matrix was diluted prior to measurement without compromising analytes detectability.

Sodium tetrahydroborate (NaBH₄) was employed as a reducing agent for the in-line generation of mercury vapor via the cold vapor technique. No additional dilution was required, which was advantageous given the expected low concentrations of Hg in the samples.

Following optimization, the methods were validated by evaluating linearity, limits of detection (LOD) and quantification (LOQ), precision, and trueness.

The LOQ values obtained were 0.202 mg kg⁻¹ for Cd, 0.319 mg kg⁻¹ for Pb, and 0.015 mg kg⁻¹ for Hg, all below the maximum limits established by international regulations. Precision, expressed as relative standard deviation (%RSD), was evaluated using spiked samples and was below 10% for all elements. Trueness was assessed using two certified reference materials—spinach (NIST 1570a) and tomato leaves (NIST 1573a). A Student’s t-test comparison between experimental and certified values was conducted. All calculated t values were below the critical t value (0.05, 5) = 2.57, indicating no statistically significant differences at the 95% confidence level.

The obtained figures of merit confirm that the proposed method is suitable for monitoring purposes, enabling the determination of all three elements with a single sample preparation step.

Additionally, the developed methods offer several advantages over argon-plasma techniques, including lower initial investment, reduced operational costs, and decreased energy consumption, while minimizing the generation of hazardous waste. These features make MP-AES an efficient, sustainable, and practical alternative for implementation in laboratories conducting quality control of cannabis products.

Pancreatic exocrine insufficiency (PEI) is a prevalent yet frequently underdiagnosed condition associated with chronic pancreatitis, pancreatic cancer, and pancreatic resection. It results from insufficient secretion of digestive enzymes, leading to impaired nutrient absorption, weight loss, and micronutrient deficiencies. Conventional diagnostic methods, such as the coefficient of fat absorption (CFA) and fecal elastase testing, are hindered by technical complexity, limited patient adherence, and suboptimal diagnostic performance. These limitations underscore the pressing need for alternative diagnostic strategies based on reliable, non-invasive biomarkers.

In this context, urine represents a promising biological matrix for biomarker discovery, as it could be collected non-invasively and reflects systemic metabolic changes. This study presents the development and validation of a multielemental analytical method employing inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) for the accurate quantification of metals and metalloids in human urine. The ultimate objective was to evaluate its applicability in identifying elemental signatures associated with PEI and related metabolic dysfunctions.

The analytical protocol was optimized to address main challenges associated with urine analysis, particularly matrix effects and spectral interferences. Strategies included appropriate sample dilution, internal standardization, and the use of collision/reaction gases were employed to reduce spectral and non-spectral interferences and to enhance the accuracy. The optimal dilution factor was determined to be 1:2, representing a balance between matrix suppression and analytical sensitivity. Method validation was carried out using certified reference materials at various concentration levels, with evaluation of trueness, intra- and inter-day precision, and detection limits.

The method enabled simultaneous quantification of more than 20 elements, including essential (Zn, Cu, Fe, Se), toxic (As, Cd, Pb), and trace elements, at concentrations ranging from low parts-per-billion to parts-per-milion levels. This multielemental approach provided a comprehensive elemental profile that may reflect biochemical alterations associated with pancreatic dysfunction.

The proposed validated methodology offered a solid analytical methodology for future clinical studies aiming to establish urinary metallomic patterns as diagnostic or prognostic biomarkers of PEI.

The determination of arsenic in clinical samples is a key analytical task in biomedical research and public health, given the toxicological and carcinogenic nature of this metalloid. Chronic exposure to inorganic arsenic is strongly associated with skin, lung, bladder, and kidney cancers, as well as cardiovascular, neurological, and metabolic disorders. Accurate quantification of arsenic in biological fluids such as blood serum and urine enables both diagnosis and monitoring of acute or chronic poisoning and supports epidemiological surveillance and health policy design.

Inductively coupled plasma mass spectrometry (ICP-MS) offers high sensitivity for trace elemental analysis. However, its applicability to biological matrices is often limited by matrix effects and the ultra-trace concentration of the analyte. Conventional sample preparation methods like acid digestion or liquid–liquid extraction involve significant drawbacks, including analyte loss, matrix degradation, high solvent consumption, toxicity, and low potential for automation.

In this context, this work presents an innovative solid-phase microextraction strategy that employs a novel class of sorbent materials referred to as Guefoams (guest-containing foams). These materials consist of a porous metallic matrix - specifically aluminum - within which freely mobile particulate entities, designated as guest phases (in this case, activated carbon), are physically entrapped in the internal cavities of the host structure. The structural features of Guefoams confer a high specific surface area, mechanical robustness, and tailored porosity, allowing complete exposure of the functional guest surfaces for selective adsorption.

The sorptive performance of Guefoams for arsenic was investigated. Optimization of adsorption and desorption conditions was carried out using a Box-Behnken experimental design. The best desorption efficiency was achieved with 5% HNO₃, reaching a preconcentration factor of 2. Limits of detection were in the order of ng kg-1, making the method suitable for trace-level analysis in clinical matrices. Adsorption efficiency showed no significant differences among arsenic species, indicating good versatility. Moreover, method accuracy was validated through the analysis of certified reference materials, including two urine and two blood serum samples, with recoveries close to 100%.

These results demonstrated that Guefoams represent a promising alternative for the preconcentration and determination of arsenic in complex biological samples, offering operational simplicity, cost-effectiveness, low environmental impact, and compatibility with ICP-MS detection.

Accurate determination of arsenic in tire pyrolysis oils (TPOs) is essential due to its environmental toxicity, impact on fuel stability, and deactivation of catalysts in refining processes. Although inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) is renowned for its sensitivity and low detection limits, its application to organic matrices such as TPOs is hindered by plasma instability, spectral interferences, and soot deposition. Interfering ions such as 40Ar35Cl+, 38Ar37Cl+, 59Co16O+, 40Ca35Cl+, Sm2+ and 150Nd2+ overlap with 75As+ peaks, thereby complicating the quantification. Moreover, the complexity of the matrix could affect all stages of the analytical process, from nebulization to ionization, leading matrix effects and varying arsenic chemical forms, which could degrade the accuracy of determination.

To address these analytical challenges, in this work, we present a robust method that combined a high-temperature torch integrated sample introduction system (hTISIS), operated at 400 °C, with ICP-MS/MS, applied to TPOs previously diluted 1:10 in xylene. The hTISIS enabled efficient aerosol evaporation and enhanced analyte transport, resulting in signal intensities up to 20 times greater than those observed with a conventional sample introduction system. The use of oxygen as a reaction gas allowed effective mitigation of chloride-based polyatomic interferences, even in samples with chlorine levels exceeding 750 mg kg⁻¹.This configuration yielded arsenic detection limits as low as 2 ng kg⁻¹ and procedural quantification limits (pLOQ) of 60 ng kg⁻¹, an order of magnitude better than conventional systems. Furthermore, the combination of hTISIS and ICP-MS/MS successfully mitigated both matrix-induced effects and the influence of arsenic speciation.

Thirteen TPO samples, originating from diverse tire types and production processes, were analyzed, revealing arsenic concentrations ranging from 41 ± 4 to 924 ± 80 µg kg⁻¹. Results were validated via comparison with a reference method based on microwave-assisted acid digestion and conventional ICP-MS. Statistical analysis showed no significant differences for most samples at the 95% confidence level. Overall, the hTISIS–ICP-MS/MS configuration provided a sensitive, accurate, and operationally simple solution for the routine determination of arsenic in complex organic matrices.

Catalytic carbon dioxide hydrogenation distinguishes as a potential technology due to the possibility of producing high-added value products such as methanol, formic acid and others, including gasoline. Furthermore, it is estimated that on long term, CO2 conversion is about 40 times more efficient in solving the climate change issue than its sole capture and storage CO2 [1]. The most investigated and widely used catalytic system is the Cu/ZnO/Al2O3, where copper is the main actor, ZnO is seen as co-catalyst and alumina is a kind of stabilizer for both. However, the mechanism and role of each component is still under debate. Typical routes to prepare metal oxide-based catalysts consist in precipitation methods followed by calcination. For example, Zinc-Copper mixed oxides were made by co-precipitating zinc/copper basic carbonates and then by thermally treating them [2]. It can be seen that the choice of Cu/Zn nitrates molar ratios and the precipitation approach can lead to different mixed products (basic carbonates or nitrates) Here we report on the comparison between a batch precipitation [2] and a titrimetric method [3] to synthesize catalyst precursors. Fourier Transform Infrared spectroscopy operated in attenuated total reflectance mode allowed the identification of the as-produced compounds. Moreover, TEM analysis provided information about morphology. Results indicate that the titration approach allows a fine tuning of the final product. Calcination above 350°C was also performed at different temperatures to prepare oxides. Data on their catalytic role in CO2 hydrogenation are also provided.

References:

[1]. J.L. Neto, O.T. Barros, B.S. Archanjo, O. Kuznetsov, J.B. dos Santos, C.A. Franchini, E.J. Corat, A.M. Silva, Catalysis Today 442 (2024) 114957.

[2] R.G. Herman, K. Klier, G.W. Simmons, B.P. Finn, J.B. Bulko, J. Catal., 56 (1979) 407

[3] M. Behrens, D. Brennecke, F. Girgsdies, S. Kißner, A. Trunschke, N. Nasrudin, S. Zakaria, N.F. Idris, S.B. Abd Hamid, B. Kniep, R. Fischer, W. Busser, M. Muhler, R. Schlogl, Applied Catalysis A: General 392 (2011) 93–102

Research funded by European Union - Next Generation EU, Mission 4 Component 1 CUP F93C24000420006 – “MACACO” project.

Characterization Of Smart Materials: A Vibrational Spectroscopy Approach

Michael Freduah Agyemang (a,b), Stefan Zechel (c,d), Martin D. Hager (c,d,e), Michael Schmitt (a), Juergen Popp (a,b)

(a) Institute of Physical Chemistry (IPC), Abbe Center of Photonics (ACP), Friedrich Schiller University Jena, Helmholzweg 4, 07743 Jena, Germany;

(b)Leibniz Institute of Photonic Technology, e.V Jena, Albert-Einstein-Str. 9, 07745 Jena, Germany;

(c)Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldstr. 10, 07743 Jena, Germany;

(d)Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany

(e)HIPOLE Jena, Philosphenweg 7a, 07743 Jena, Germany

Smart materials are materials engineered to respond predictably to external stimuli such as temperature, change in pH value or light, often enabled by reversible mechanisms in their molecular structure. Their functionality is controlled by active centers or moieties, which are embedded within a complex matrix, e.g., polymer network. Gaining insights into the behavior of these active centers within their complex environment is crucial for understanding the molecular dynamics processes. This calls for the use of non-invasive analytical techniques such as vibrational spectroscopy, which can be combined with advanced evaluation and computational algorithms like two-dimensional (2D) correlation analysis and Density Functional Theory (DFT).

Here, we are currently investigating smart polymers with self-healing functionality. Our focus is on intrinsic self-healing polymers, which are based on the reversible interactions (e.g., reversible covalent bonds, supramolecular interactions) within the polymer matrix. The dynamic bonds can be metal-ligand interactions, Diels-Alder reactions, disulfide bonds, acylhydrazone bonds, just to mention a few.

We employ vibrational techniques like Raman and IR spectroscopy to unravel the complex molecular mechanisms underlying their self-healing processes. These methods are non-destructive, highly specific, and powerful tools for probing chemical structures, monitoring reaction pathways, and capturing dynamic processes in real time. In addition to these techniques, analytical techniques like 2D correlation analysis will be utilized to untangle the intricate correlations between different spectral features and DFT calculation to provide theoretical foundation for experimental interpretations. Together, these techniques offer complementary perspective that help understand the intricate molecular dynamics at play in these self-healing materials.

Acknowledgements: The authors would like to thank Deutsche Forschungsgemeinschaft (DFG) for their support and funding under project number 455748945.

References

1. T. Baetz, M. Agyemang, J. Meurer, J. Hniopek, S. Zechel, M. Schmitt, J. Popp, M. D. Hager and U. S. Schubert, Dual orthogonal metal-complexes and their utilization for the versatile fabrication of smart interpenetrating polymer networks, Polymer Chemistry, 2024, DOI: 10.1039/D4PY01079E.

2. https://doi.org/10.1080/17452759.2025.2499470 (yet to be published online).

Microplastics (MPs) are emerging pollutants of increasing environmental and health concern, primarily due to their persistence, ubiquity across ecosystems, and capacity to interact with toxic substances. These small synthetic particles could originate either from the degradation of larger plastic debris or from their direct manufacture for specific applications. Once in the environment, MPs could adsorb and transport hazardous trace elements such as heavy metals and metalloids in the so-called Trojan-horse effect. Evaluating the fraction of these elements that becomes bioaccessible during digestion is key to understanding potential health risks.

This study aimed to quantify the gastrointestinal bioaccessibility of eight trace elements (As, Br, Cd, Cr, Pb, Sb, Sn, and Zn) leached from low-density polyethylene MPs (ERM®-EC680m) under simulated human digestive conditions. Two validated static in vitro digestion protocols were applied: the Unified BARGE Method (UBM), mimicking fasting conditions, and the Versantvoort model, simulating digestion after food intake. Both procedures included sequential exposure of the MPs to artificial saliva, gastric fluid, duodenal juice, and bile at 37 °C, under dark conditions. Quantification of released analytes was carried out using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), employing helium as a collision gas to reduce polyatomic interferences.

The Versantvoort model resulted in markedly higher bioaccessibility values compared to UBM, particularly for As (108 ± 6%), Br (92.3 ± 1.7%), and Zn (48 ± 5%). Conversely, Pb, Cd, Cr, Sn, and Sb exhibited lower bioaccessibility, ranging from 0.5 ± 0.1% (Cd) to 10.8 ± 1.6% (Cr). The influence of MP mass and particle size was also examined under fed-state conditions. An inverse relationship was found between MP quantity and bioaccessibility for Sb, Sn, and Zn: Sb decreased from 5.8 ± 1.8% to 1.0 ± 0.4%, Sn from 0.6 ± 0.2% to 0.08 ± 0.02%, and Zn from 9 ± 3% to 1.19 ± 0.06%, as MP mass increased from 0.2 g to 2.0 g. In contrast, particle size had no significant impact on bioaccessibility. MPs were categorized into three size fractions (>0.84 mm, 0.84–0.5 mm, and 0.5–0.25 mm), with Pb and Cr bioaccessibility showing minor variation across sizes (e.g., Pb: 39.4 ± 1.6% in the largest fraction vs. 35 ± 2% in the smallest; Cr: 2.79 ± 0.12% vs. 3.1 ± 0.7%).

As a proof of concept, the method was applied to real MPs recovered from recycled rubber turf pellets used in outside surfaces and playgrounds. This demonstrated the applicability of the approach for assessing potential human exposure to inorganic contaminants associated with environmental MPs under realistic ingestion scenarios.

Oligomeric proanthocyanidins (OPCs) are bioactive polyphenols known for their versatile and health-promoting properties. In particular, OPCs with a degree of polymerization (DP) between two and four are considered bioavailable, rendering them highly relevant for research and industry, especially as active ingredients in dietary supplements.[1, 2] However, the selective isolation and identification of these bioactive compounds from complex natural sources such as grape seeds – a sustainable, cost-effective by-product of the wine industry – remain a significant analytical challenge due to their structural diversity, low concentration, and susceptibility to degradation, highlighting the demand for robust analysis strategies.[3]

To address these isolation challenges, 3D-printed molecularly imprinted polymer (3DMIP) cartridge inserts present a promising, selective, and cost-efficient alternative to conventional purification techniques. These tailor-made materials are designed to recognize specific structural features and thus efficiently bind and enrich the targeted OPCs.

Herein, a solution for classification and characterization of OPCs in grape seed extracts using infrared attenuated total reflection (IR-ATR) spectroscopy in combination with multivariate data analysis is demonstrated. A spectral database was established using reference compounds and purified fractions. Principal component analysis (PCA) was then applied to correlate spectral variations with the composition and DP of OPCs. The focus was specially on distinguishing between monomers, bioavailable and bioactive OPCs and higher polymerized forms.

The developed spectroscopic method provides a rapid, solvent-free, and non-destructive alternative to conventional chromatographic techniques. Combined with selective enrichment via 3DMIPs, this approach enables efficient targeted purification and quality control of OPC-containing products for industrial and research applications.

References

1. Rauf, A. et al. Proanthocyanidins: A comprehensive review. Biomed. Pharmacother. 116, (2019).

2. Ou, K. & Gu, L. Absorption and metabolism of proanthocyanidins. J. Funct. Foods 7, 43–53 (2014).

3. Kuhnert, S., Lehmann, L. & Winterhalter, P. Rapid characterisation of grape seed extracts by a novel HPLC method on a diol stationary phase. J. Funct. Foods 15, 225–232 (2015).

Microscopy is one of the standard analytical methods for characterizing biological samples. It is routinely used in many fields to investigate the structure of samples and identify patterns or anomalies by visually assessing an image. However, typical light microscopy is limited to visible light, which gives little information on the chemical composition of a sample. To obtain additional – ideally molecular - information, hyperspectral imaging presents a powerful technique, combining the advantages of spectroscopy and imaging. With this method, a two dimensional, spatially resolved image is recorded, with each pixel location representing a spectrum [1]. This additional third dimension allows for the analysis of a sample not only visually but also through its diverse spectral signatures in a single measurement. Thus, insight into the sample composition is provided by extracting spectral information using multivariate data analysis routines. Furthermore, classification strategies can be useful for recognizing patterns and for differentiating between two or more cases (e.g. healthy vs. diseased).

The versatility of molecular imaging techniques facilitates applications in a wide range of scenarios. An interesting spectral regime in hyperspectral imaging is the mid-infrared (MIR) region since IR spectroscopy is a common analytical method to characterize various samples. This method offers many advantages, such as obtaining molecular specific information quickly in a non-destructive process, allowing for the label free extraction of chemical information that is both qualitatively and quantitatively possible. The emergence and recent integration of quantum cascade lasers (QCLs) into IR microscopy provides a significant advancement, revolutionizing its application in the clinical field. The SPERO microscope, developed by Daylight Solutions, exemplifies this innovation [2]. In comparison to conventional IR microscopy using broadband thermal light sources usually requiring a Fourier transformation (FT) for achieving spectrally resolved data, tunable QCL light sources scan a range of wavelengths with a high energy density. Albeit covering a narrower spectral window, significantly shorter analysis times are resulting while preserving comparable spatial and spectral resolution. This advancement fulfills the clinical need for fast and reliable diagnostic analysis.

The current state of research demonstrates the capability of such a QCL IR microscope in addressing various research questions, with the objective of quickly characterizing samples with detailed spectral information at a microscopic level. The potential scope of research ranges from the analysis of polymers to biological materials. To establish a basic understanding of how the SPERO microscope operates and how to handle and evaluate the resulting hyperspectral data, the objective of this work was to carry out fundamental measurements as proof of principle studies and generate a workflow for sample analysis. After using principal components analysis (PCA) as an exploratory unsupervised data evaluation method to identify patterns and trends within the obtained MIR hyperspectral images, classification by partial least squares – discriminant analysis (PLS-DA) was carried out. The obtained results show a successful differentiation between different polymer materials in the case of analyzing blank sample slides, a visual identification of crystallized caffeine in coffee and black tea by assessing images of class prediction probability and a discrimination between fungal contaminated and non-contaminated wheat kernels. In the future, the identification of tumor tissue to diagnose and characterize different cancer types by applying classification models using hyperspectral images obtained by QCL-IR microscopy is a central and promising field of research [3].

[1] Schultz, R. A. , Nielsen, T. , Zavaleta, J. R. , Ruch, R. , Wyatt, R. , and Garner, H. R. Hyperspectral Imaging: A Novel Approach for Microscopic Analysis. Cytometry 2001, 43, 239–247.

[2] Spero® Chemical Imaging Microscope: Real-time QCL-IR Spectroscopy. https://www.daylightsolutions.com/products/spero/ (accessed May 23, 2025).

[3] Kuepper, C. , Kallenbach-Thieltges, A. , Juette, H. , Tannapfel, A. , Großerueschkamp, F. , and Gerwert, K. Quantum Cascade Laser-Based Infrared Microscopy for Label-Free and Automated Cancer Classification in Tissue Sections. Scientific Reports 2018, 8

Helium is one of the most important, if not the most important refrigerant in cryogenics. Generating temperatures as low as the normal boiling point of helium (4.2 K) are easily achievable using helium. Using other helium-based technologies such as evaporation cooling or 3He-4He dilution refrigeration, even lower temperatures down to ~10 mK can be achieved. The purity of the helium is crucial here. Even minute traces of hydrogen, ranging from 10⁻⁹ to 10⁻⁷, are enough to cause laboratory flow cryostats to fail due to blocking. Adequate analysis methods are therefore essential in cryogenics.

This paper presents a simple spectrometric setup and the figures of merit achieved with it. The flowing sample gas is precisely conditioned to an absolute pressure of a few millibar inside a glass tube. This tube is located within a 3/4 lambda Broida cavity. A plasma is ignited by a spark generator and continuously excited using a microwave generator. Finally, the plasma is analysed by optical emission spectrometry. The hydrogen, neon and oxygen lines are of particular interest here, as are the nitrogen bands. A range of factors was investigated, including the impact of the detector exposure time, the effect of the microwave power coupled into the cavity, the role of the plasma pressure, and the significance of the flow velocity. After optimising these parameters, the setup has been calibrated for hydrogen. Based on the analysis of the H-alpha spectral line, the detection and quantification limits for hydrogen were found to be in the range of 10⁻⁶.

Infrared and Raman spectroscopy hold great promise for clinical applications. However, the inherent complexity of the associated spectral data necessitates the use of advanced machine learning techniques which, while powerful in extracting biological information, often operate as black-box models. Combined with the absence of standardized datasets, this hinders model optimization, interpretability, and the systematic benchmarking of the growing number of newly developed machine learning methods. To address this, we propose a simulation-based framework for generating fully synthetic spectral datasets using Monte Carlo approaches for benchmarking. The artificial datasets mimic a wide range of realistic scenarios, including overlapping spectral markers and non-discriminant features and can be adjusted to simulate the effect of different parameters, such as instrumental noise, number of interferences, and sample size. These spectra are simulated through the generation of Lorentzian bands across the mid-infrared range, without specific reference to experimental data or chemical structures. We used the proposed methodology to compare different spectral marker identification protocols in a partial least squares discriminant analysis (PLS-DA), showing that the orthogonal PLS-DA (OPLS-DA) approach, when combined with marker selection based on VIP scores or the regression vector, yielded higher sensitivity, specificity, and interpretability than standard PLS-DA using the same selection criteria. This framework was further used to benchmark the classification capabilities of commonly employed machine learning algorithms, incorporating both linear and non-linear markers reflective of compositional variations across the target classes. Key findings were validated using real infrared spectra from human blood serum and saliva collected in the frame of a clinical study. Overall, the proposed approach provides a versatile sandbox environment for the systematic evaluation of data analysis strategies in vibrational spectroscopy, that can help experimentalists to better interpret spectral markers or data analysts focused on benchmarking and validating new algorithms.

Liquid crystal (LC) devices with improved electro-optical properties are currently in active development. One of the promising areas is ferroelectric liquid crystals. The propagation of intense light beams in such media can be accompanied by their interaction, and such interaction can be controlled or switched by optical means. However, the structural characteristics of such molecules also play an important role. Recently, a new optically active molecule [1] containing a quaternary ammonium group, promising for liquid crystal systems, was synthesized (N-[4-((2R)-octan-2-yloxy)benzyl]-N,N-dimethylhexadecyl-1-ammonium tosylate; 1).

As was shown in [2–4], vibrational circular dichroism (VCD) spectra give full information about the absolute configuration of molecules. In this work, we analysed the sensitivity of the VCD and IR spectra of 1 to the mutual spatial orientations of the functional groups and estimated the probabilities of the second harmonic generation (SHG) by this molecule for a number of wavelengths in optical region. The equilibrium configuration, VCD and IR spectra of 1 were calculated at the B3LYP/6-311G level of theory. Then the mutual orientations of two functional groups containing the oxygen and the nitrogen atom, respectively, were changed by rotation around single bonds, and for such configurations the VCD and IR spectra were calculated anew. Comparison of the calculated VCD and IR spectra has shown that they are both very sensitive to the mutual orientation of the functional groups and can serve as a basis for assignment of such experimental spectra. For the monomer and some associates of 1, the calculation of the components of the first cubic and second quaternary hyperpolarizability tensor of the type β(-2ω,ω,ω) and γ(-2ω,ω,ω,0), which determine the efficiency of the second harmonic generation (including that induced by an external electric field γ(-2ω,ω,ω,0)), was carried out at the B3LYP/6-311G level of theory for the following wavelengths: 759.4, 569.5 and 455.6 nm. Analysis of the calculated data shows that the SHG efficiency increases nonlinearly with decreasing wavelength of the incident light. The greatest effect is achieved when the light flux is directed perpendicular to the direction of the dipole moment of the LC molecule (along the X axis), which is directed along the Y axis. Switching on an external electric field does not change the trends described above, but significantly increases the efficiency of the SHG process.

Keywords: VCD, IR spectra; LC molecules, SHG, configurations

Acknowledgements

This study was supported by the Belarusian State Program of Scientific Investigations 2021–2025 “GPNI Chemical processes, reagents and technologies, bioregulators and bioorgchemistry” (2.1.01.04). The work of A.A.K. was funded by the Ministry of Science and Higher Education of the Russian Federation as a state assignment for the Saratov Federal Scientific Centre of the Russian Academy of Sciences (research topic no. 124020100147-6).

References

[1] G. Pitsevich, I. Doroshenko et al., J. Mol. Cryst. Liq. Cryst., 748 (2022) 73–81.

[2] M.A.J. Koenis, C.S. Chibueze et al., Chem. Sci., 11 (2020) 8469–8475.

[3] S.R. Bhattacharya, T. Bűrgi, Nanoscale, 11 (2019) 23226.

[4] L.A. Nafie, J. Phys. Chem. A, 108 (2004) 7222–7231.

Increasing industrialization, intensive agricultural activities and climate change have significantly decreased the quality of water available for consumption, putting global health at risk. To minimize the occurrence of harmful pathogens like viruses, bacteria and protozoa, drinking water is subjected to a treatment process that includes disinfection, promoting the oxidative destruction of these microorganisms and preventing many waterborne diseases. However, the presence of natural organic matter (NOM) in the raw water supplied to this process can react with disinfection agents, usually free chlorine, and lead to the formation of unwanted disinfection byproducts (DBPs). Exposure to high concentrations of these DBPs may lead to asthma, cancer, or experience teratogenic, mutagenic or reproductive problems. Silica-based aerogels are an attractive alternative to remove these DBPs from water, due to their simple synthesis process and wide availability of silanes that can confer a variety of targeted properties to the final material.

We developed two silica-based aerogels based on hydrolyzed methyltrimethoxysilane (MTMS) and 3-aminopropyltriethoxysilane (APTES), with distinct surface charge using the sol-gel method. We studied their potential to remove DBPs from water, namely bromodichloromethane (BDCM) and monochloroacetic acid (MCAA), two representatives of the most predominant DBP families found in drinking water - trihalomethanes and haloacetic acids. These tests revealed a good capacity of the aerogels to rapidly remove this type of pollutants when at ppb level. To better understand how these aerogels work on a molecular level, we also conducted quantum chemistry calculations to survey how these two pollutants are adsorbed by hydrolyzed MTMS or APTES building blocks. In the future, we will validate these theoretical results using rotational spectroscopy, a powerful technique that can unambiguously distinguish different molecular species based on their structural properties. In this contribution, we will discuss how looking at the physics and chemistry of DBP adsorption using rotational spectroscopy can be a helpful tool to understand and guide the synthesis of new materials for water treatment.

Acknowledgments: Funded by the European Union, under the Grant Agreement GA101081963 attributed to the project H2OforAll - Innovative Integrated Tools and Technologies to Protect and Treat Drinking Water from Disinfection Byproducts (DBPs). This research was co-funded by the European Regional Development Fund (ERDF). This work was also supported by national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., within the projects 10.54499/UIDB/00102/2020, 10.54499/UIDP/00102/2020, 10.54499/UIDB/04564/2020, 10.54499/UIDP/04564/2020.

The authors acknowledge FCT for the advanced computing grants with references 2023.10981.CPCA.A2, 2024.07904.CPCA.A3 as well as the computational resources provided by the Laboratory for Advanced Computing at University of Coimbra, Minho Advanced Computing Center (MACC), and by Fundação para a Computação Científica Nacional (FCCN).

M.I.R. and N.M.C. acknowledge the PhD scholarships from FCT with references 2024.03908.BDANA and 2023.00840.BD, funded by national funds.

This work was funded by the European Union (ERC, 101040850 - MiCRoARTiS).

Background: Timely and accurate detection of blood contamination in cerebrospinal fluid (CSF) is critical in neurosurgical practice. While UV-Vis spectrophotometry remains the clinical gold standard for detecting xanthochromia in cerebrospinal fluid (CSF)—specifically targeting oxyhemoglobin (~413–415 nm) and bilirubin (~450–460 nm)—these methods are optimized for electron transitions and not for broader molecular profiling. Fourier transform infrared spectroscopy (FTIR), which probes vibrational modes rather than electronic transitions, is not routinely applied in this context. However, FTIR offers an orthogonal strategy for characterizing bulk biochemical changes associated with blood contamination, independent of pigment-specific absorption. Crucially, FTIR operates at room temperature, requires no reagents, and enables rapid detection of shifts in metabolic patterns of biological fluids—making it potentially attractive for bedside use in neurosurgical settings.

Methods: We applied full-range FTIR spectroscopy (4000–400 cm⁻¹, 4 cm⁻¹ resolution, Bruker Alpha II) to 50 clinical CSF samples (clinically validated: 29 uncontaminated, 21 blood-contaminated). A robust preprocessing pipeline was implemented: Savitzky–Golay baseline correction (window = 51, polyorder = 3, 3 iterations), multiplicative scatter correction (2nd-degree polynomial), standard normal variate (SNV), and z-score standardization. A mean difference spectrum (CSF_bloody – CSF) was computed, and statistical significance across wavenumbers was assessed using unpaired t-tests with Benjamini–Hochberg FDR correction (α = 0.05).

Results: Significant differences were observed in vibrational regions consistent with blood-borne macromolecular components. Specifically, the amide I (~1650 cm⁻¹) and amide II (~1545 cm⁻¹) bands showed elevated absorbance in contaminated samples, reflecting increased protein content (e.g., hemoglobin). Additional differences were detected in the CH-stretching region (2850–2950 cm⁻¹), likely due to lipid-rich plasma fractions, and in the C=O and N-H stretching bands (~1700–1750 cm⁻¹ and 3300–3500 cm⁻¹), consistent with bilirubin-like compounds. Although FTIR lacks sensitivity for chromophore-specific electronic transitions, these vibrational markers provide a reproducible and statistically robust molecular fingerprint of contamination.

Conclusion: This work demonstrates that FTIR spectroscopy—despite not targeting chromophores directly—can effectively discriminate blood-contaminated CSF through robust vibrational profiles. The method's simplicity and lack of sample preparation offer significant potential for clinical translation. FTIR could enable a preparation free bedside assessment of CSF for blood contamination using a single drop—facilitating monitoring and surveillance of patients after surgery for brain and spine lesions with early detection of re-bleeding.

Biophotonics has transformed our ability to investigate biological and biomedical systems by leveraging the interactions between light and matter. Modern biphotonic techniques offer high-resolution insights into molecular structures, cellular dynamics, and tissue organization. Among the many tools in biophotonics, molecular spectroscopy (e.g. fluorescence, IR or spontaneous and coherent Raman spectroscopy) stands out as particularly powerful and versatile methods, enabling both morphological and chemical characterization of a broad variety of biomedical samples.

This lecture will explore how the integration of multimodal spectroscopy in combination with AI is revolutionizing biomedical and clinical diagnostics. We will focus on two primary domains: intraoperative spectral histopathology and infectious disease management, while also addressing further emerging applications across healthcare, environmental science, and bioanalytics.

One of the most impactful clinical applications lies in surgical oncology. A key challenge during tumor resections is the real-time identification of cancerous versus healthy tissue to ensure complete removal while preserving surrounding structures. Traditional histopathological analysis is limited by its post-operative nature and time requirements. Coherent Raman spectroscopy, integrated into multimodal imaging systems, offers real-time, in situ chemical and morphological contrast that supports more accurate intraoperative decision-making. When augmented with AI, these systems can automatically interpret complex spectral data and provide immediate diagnostic feedback to surgeons. The fusion of advanced optical imaging - such as coherent anti-Stokes Raman scattering (CARS), two-photon excited fluorescence (TPEF), and second harmonic generation (SHG) - with AI-assisted image analysis paves the way toward precision-guided surgery. Importantly, the addition of laser ablation capabilities enables a "seek-and-treat" workflow where identified malignant tissues can be directly removed, bringing diagnostics and therapy into a single, efficient process.

Beyond oncology, molecular spectroscopy has shown great promise in the field of infectious disease diagnostics. The rapid identification of pathogens, including antibiotic-resistant strains, remains a major global health challenge. Raman-spectroscopy based approaches provide a rapid alternative to culture-based or PCR-based diagnostics and are well-suited for point-of-care and on-site applications. Our work focuses on the development of compact, portable instruments that can acquire and analyze patient samples in minutes. With the support of AI, these tools enable robust identification of microbial species, resistance profiling, and even monitoring of host immune responses, all critical for timely and personalized therapeutic interventions.

Importantly, our approach spans the entire diagnostic workflow - from sample collection and spectral acquisition to real-time data analysis and clinical decision-making. AI models trained on extensive spectral datasets can perform complex classification and pattern recognition tasks, transforming raw data into actionable insights. This accelerates the diagnostic process and reduces dependence on specialized expertise, making high-end diagnostics more accessible and scalable.

In addition to cancer and infectious diseases, advanced (micro-)spectroscopic methods - including Raman, IR, and fluorescence techniques allow to address challenges in biology, and life sciences. A major focus lies in investigating biological processes at the molecular level, such as the uptake and localization of active molecules in cells, also using intelligent Raman tags.

The technique’s broad adaptability is further enhanced by advances in miniaturized, robust hardware and cloud-connected AI systems, which allow for remote operation and centralized data processing.

The success of the aforementioned applications depends not only on technological innovation but also on strategic translational infrastructure. To ensure the clinical viability we are developing pathways that bridge the divide between laboratory research and clinical translation.

Overall, this lecture will showcase how advanced multimodal (micro-)spectroscopic methods, empowered by AI, is poised to redefine medical diagnostics—making them faster, more accurate, and more accessible. Whether guiding surgeons in real time, identifying life-threatening infections, or providing molecular-level insights into complex biological systems, this powerful synergy is laying the foundation for a new era of intelligent, personalized medicine.

Acknowledgment: Financial support of the EU, the ”Thüringer Ministerium für Wirtschaft, Wissenschaft und Digitale Gesellschaft”, the ”Thüringer Aufbaubank”, the Federal Ministry of Education and Research, Germany (BMBF), the German Science Foundation, and the Carl-Zeiss Foundation are greatly acknowledged.

Photochemical reactions are emerging as transformative tools for sustainable chemical manufacturing, offering energy-efficient pathways to synthesize fine chemicals, pharmaceuticals, and renewable fuels while minimizing waste and fossil fuel dependence. However, their industrial adoption hinges on overcoming critical scalability challenges tied to photon and mass transport and eventually reactor design. Due to the complex interaction of the different transport processes, the transfer of photochemical processes from laboratory to industrial scale remains a considerable challenge.

The availability of photons to drive reactions is governing not only the reaction rate but also determines selectivity and lifetime of catalytic systems. End-point analysis, for instance with gas chromatography, often only provides information on the overall activity after the catalytic system is not active anymore, without the possibility to conclude on the reasons of e.g. deactivation or observed selectivity. Online spectroscopy allows to bridge the gap between the macroscopically observed activity and the underlying chemical reasons as time-resolved, i.e. kinetic, information can be obtained.

This contribution will discuss recent results on the effect of dynamic irradiation on the efficiency of light-driven water splitting. The overall activity could be improved by a factor of more than 10 with respect to the turnover number and a factor of 31 referring to the external energy efficiency by controlling the local availability of photons. Detailed insights into the mechanism of light driven water oxidation could be obtained using complementary methods of investigation like Raman, IR, and UV/Vis/emission spectroscopy, unraveling the importance of avoiding high concentrations of excited photo-sensitizers.

Spectroelectrochemistry, particularly the combination of electrochemical techniques with vibrational spectroscopy, such as Raman or mid-IR spectroscopy, has gained significant interest. This is because it provides molecular information on electrochemically or interfacially driven processes at the solid/electrolyte interface, offering selectivity, sensitivity and, depending on the combined platform, temporal and spatial resolution [1, 2]. Various approaches have been employed in the development of experimental setups, including hybrid analytical platforms that combine electrochemical and/or molecularly specific information with spatially resolved measurements. Boron-doped diamond (BDD) is highly suitable for spectroelectrochemical investigations in the mid-IR region as an IR-transparent electrode. It is characterized by a large potential window, a broad spectroscopic window, chemical inertness and favorable signal-to-noise ratios [3]. BDD's excellent chemical and physical properties, and the ability to fabricate BDD-modified diamond ATR crystals, render it highly suitable for spectroelectrochemical applications. Examples of such combined measurements include the electrochemical deposition of conducting polymers, which was investigated via AFM and IR-ATR. AFM provides the advantage that additional information, such as adhesion forces, can be obtained. To improve electrochemical sensitivity and take advantage of surface-enhanced infrared absorption (SEIRA), BDD can be modified electrochemically with metal nanoparticles, such as gold and silver (NPs) [4].

This contribution presents combined scanning probe techniques with mid-IR ATR spectroscopy for in situ investigations of processes occurring at BDD or Au nanoparticle-modified BDD surfaces. Additionally, the potential of mid-IR spectroelectrochemistry to provide mechanistic insight into light-driven water oxidation catalysis (WOC) is explored [5].

Solar radiation is the principal source of energy on Earth and has unmatched potential for the synthesis of organic material from primordial molecular building blocks. Providing the energy for photochemical synthesis of (proto)biomolecules, light has also been found to often provide remarkable selectivity in these processes. Reactivity and selectivity in photochemical prebiotic synthesis is a topic of long interest.[1-6]

There is much evidence suggesting that HCN (hydrogen cyanide, or formonitrile) was important in prebiotic synthesis.[7] Diaminomaleonitrile (DAMN, chemical formula C₄N₄H₄) is the most prominent low molecular weight product formed during the condensation of HCN to oligomers.[8, 9] The major interest in DAMN is concerned with its significance in the prebiotic synthesis of adenine (chemical formula C₅N₅H₅) and other heterocycles under the primitive Earth conditions.[9, 10]

In the present work we explore the UV-induced photochemistry of DAMN monomers isolated in a cryogenic inert matrix.[11] Photoinduced hydrogen-atom transfer was found to be the major process occurring upon UV-irradiations of DAMN. The transfer of a hydrogen atom from NH₂ group to a nitrile fragment resulted in isomerization to another open-ring tautomer of DAMN involving a ketenimine group. Another photoinduced reaction resulted in the formation of the heterocyclic compound, amino-imidazole-carbonitrile (AICN, chemical formula C₄N₄H₄). Hereby we proved that the light-induced cyclization of DAMN is its intrinsic property, which occurs on the monomeric level and without any solvent involved. We also show that the ring-closure photochemistry of DAMN, via ketenimine isomer, is selective and leads to only one specific tautomeric form of AICN. The mechanistic analysis of the observed transformations will be presented.[11]

Funding

Funded by the European Union, project H2OforAll: Innovative Integrated Tools and Technologies to Protect and Treat Drinking Water from Disinfection Byproducts (Grant Agreement GA101081953). The Research Centre on Chemical Engineering and Renewable Resources for Sustainability (CERES) is supported by the Portuguese Science Foundation (“Fundação para a Ciencia e a Tecnologia”, FCT) through FCT projects UIDB/EQU/00102/2020, DOI: https://doi.org/10.54499/UIDB/00102/2020 and UIDP/EQU/00102/2020, DOI: https://doi.org/10.54499/UIDP/00102/2020 (National Funds).

References

1. R. Sanchez, J. Ferris, L.E. Orgel, Science 1966, 153, 72.

2. J.P. Ferris, J.E. Kuder, A.W. Catalano, Science 1969, 166, 765.

3. A.W. Erian, Chem. Rev. 1993, 93, 1991.

4. M. Yadav, R. Kumar, R. Krishnamurthy, Chem. Rev. 2020, 120, 4766.

5. N.J. Green, J. Xu, J.D. Sutherland, J. Am. Chem. Soc. 2021, 143, 7219.

6. K. Michaelian, Entropy 2021, 23, 217.

7. R.A. Sanchez, J.P. Ferris, L.E. Orgel, J. Mol. Biol. 1967, 30, 223.

8. S. Nandi, D. Bhattacharyya, A. Anoop, Chem.-Eur. J. 2018, 24, 4885.

9. J.P. Ferris, L.E. Orgel, J. Am. Chem. Soc. 1965, 87, 4976.

10. J.P. Ferris, L.E. Orgel, J. Am. Chem. Soc. 1966, 88, 1074.

11. I. Reva, H. Rostkowska, L. Lapinski, Photochem 2022, 2, 448.

Alkyl substances, including normal alkanes and perfluorinated alkyl substances (PFAS), represent a challenging class of compounds to detect and identify due to their lack of polar functional groups, low reactivity, and presence in complex mixtures with numerous structural isomers. Mass spectrometry (MS) is a powerful tool for analyzing such compounds because it offers excellent selectivity andcan provide both elemental composition and structural information through fragmentation. However, the ionization of alkanes remains difficult, hindering the development of rapid and selective MS methods capable of fully exploiting MS’s potential.

Environmental analysis of polar alkyl substances is typically performed using electrospray ionization (ESI) MS and tandem MS (MSⁿ). Yet, the detectability and sensitivity for these compounds vary significantly, depending on their functional groups. Recent studies comparing total organofluorine content with compound-specific measurements reveal that most PFAS present in environmental samples are not detectable by conventional ESI-MS/MS. These undetected compounds are believed to be primarily non-polar, linear, or branched alkanes.

This study explores the application of atmospheric-pressure glow discharges, specifically the flowing atmospheric-pressure afterglow (FAPA), to chemically modify and thereby enable detection of non-polar compounds. The fundamental plasma chemistry of these ion sources was characterized using optical spectroscopy and MS to identify conditions favoring molecular transformation. For instance, the helium-based FAPA was used to convert normal alkanes into oxidized and unsaturated products via hydrogen loss. Offline analysis suggested that unsaturation and oxidation proceed via separate pathways with competing reaction rates.

In a separate experiment, FAPA was employed to functionalize and detect perfluorooctane (PFO), generating [M+O–F]⁻ ions for rapid MS detection. Accurate mass measurements and ion-optic parameter optimization enabled identification of reaction intermediates such as carboxylic acids. These insights allowed for the proposal of candidate reagent ions and reaction mechanisms based on MS² spectra. This plasma-based chemical modification approach offers a promising path toward expanding the detectability of PFAS and other non-polar compounds, enabling more comprehensive compositional analyses of environmental samples.

This presentation will focus on two different applications of an off-line and on-line separation method, coupled to either HPLC or LC-ICP-MS, for the study of aqueous suspensions of sediment or soil in contact with a target analyte. The method allows for a whole sediment or soil aqueous suspension (slurry) to be directly injected in a liquid chromatograph. A micro-extraction cell (developed in-house), positioned after the injection loop, is used to intercept the sediment/soil particles prior to the analytical column. This system can be used in a traditional HPLC setup or with hyphenated LC-ICP-MS. The off-line and on-line separation method allows the partitioning of the analyte into three compartments: dissolved phase, labile sorbed phase, and non-labile sorbed phase. Injection of the sample into the LC using a membrane filter (the off-line separation) allows for the separation and detection of dissolved phase species only. When the sample is injected without the membrane filter, the whole aqueous slurry goes into the micro-extraction cell in which the soil/sediment particles are intercepted (the on-line separation). During the on-line separation, the mobile phase acts as an extraction solvent which will carry the dissolved and extractable (labile sorbed) analytes onto the column for separation followed by detection of the combined dissolved and labile sorbed analyte phases. The non-labile fraction is determined by difference of total analyte amount minus the combined dissolved and labile sorbed analyte phases. Results from two separate studies will show how the target analytes are being distributed in the three above-mentioned compartments: dissolved phase, labile sorbed phase, and non-labile sorbed phase. The first study looks at the interaction between atrazine (a well-known pesticides) and an aqueous suspension of soil. The second study will show results from metal ions (Cu, Pb, Ni, Cd, Zn)-EDTA complexes in contact with an aqueous suspension of sediment.

Plastic waste pollution along coastal environments is a critical contributor to marine litter and a precursor to microplastic formation. Accumulated plastic debris in these zones not only threatens biodiversity but also acts as a primary source of long-term environmental contamination. This study explores the application of a ground-based hyperspectral imaging (HSI) system (DV Optics, Italy) for the detection and classification of plastic waste in sandy beach environments. The field trials were carried out at Torre Guaceto beach (Brindisi, ), located in a natural protected area along the Adriatic coast of the Apulia region (southern Italy). Hyperspectral images were acquired using a system working in the visible - near infrared spectral range (VIS–NIR: 400–1700 nm), enabling accurate differentiation of polymer types under natural lighting conditions. The proposed methodological framework includes in-field data acquisition, radiometric and spectral correction procedures and data-driven analysis for material discrimination in complex sandy environments. The results demonstrated the system’s effectiveness in identifying and classifying plastic debris, including items partially buried in sediment or obscured by vegetation. By capturing detailed spectral fingerprints of macroplastics, this approach provides a robust basis for tracing potential sources of microplastic formation, enabling early intervention and pollution mitigation. The integration of VIS–NIR information enhances detection reliability and supports the development of scalable, non-invasive tools for continuous environmental monitoring, particularly in ecologically sensitive coastal regions.

Growing environmental concerns have incited the search for environmentally and economically sustainable solutions to solid waste management challenges. The use of organic waste for compost production appears to be a viable management strategy, both at the industrial and community levels. This strategy reduces the weight and volume of waste while generating a valuable product. Compost is used as a fertilizer, and its application has demonstrated numerous benefits. These include enhanced water infiltration and retention, decreased temperature fluctuations, reduced erosion, increased biological activity, promotion of natural pest control, and increased availability of micronutrients (e.g. Cr, Cu, K, Mn) for crop sustenance and growth.

Energy dispersive X-ray fluorescence spectroscopy (EDXRF) is an analytical technique that offers several advantages, including the absence of sample preparation treatment, non-destructive analysis, and no requirement for calibration standards. However, due to its relatively high limits of detection and quantification compared to other techniques, the determination of micronutrients could be challenging.

In this work, the concentrations of Mn, Cr, Cu and K were evaluated to characterize compost from a micronutrient perspective. Compost samples were dried at 105ºC and then milled in a ball mill to achieve a 0.38 mm diameter. Analyses were performed using a Shimadzu EDX-7200 spectrometer equipped with a rhodium X-ray source. For quantification the fundamental parameters method was used. The analytical conditions were optimized using a representative compost sample. The best conditions found were: using an air atmosphere, with a 5 mm collimator diameter and a measure time of 100 s for all the analytes.

Limits of detection ranged from 1.0 to 2.6 mg kg^-1 and limits of quantification from 3.2 to 8.7 mg kg^-1. For this task, low concentrations of the analytes were added to carboxymethylcellulose. Precision (repeatability) as %RSD of 6 replicates of compost samples was less than 10% for all analytes. Trueness was evaluated using two different reference materials: soil and marandú (plant material) (Embrapa, Brasil), and spiked samples, with recoveries ranging from 77% to 117%.

Eight commercial compost samples were analysed. The elemental concentrations obtained were 8.27-13.73 mg kg^-1 for Cr, 21.24-27.69 mg kg^-1 for Cu, 5.65-8.63 mg kg^-1 for K and 388.63-632.50 mg kg^-1 for Mn.

The performance of the developed method was assessed by comparing results with those obtained by MIP OES (Cr, Mn), FAAS (Cu) and FAES (K) after microwave-assisted acid digestion. A Student’s t-test was applied, and all calculated t values were below the critical value (α = 0.05, n = 8), indicating no statistically significant differences between the proposed method and microwave acid digestion methods at the 95% confidence level.

The proposed method is simple, fast, and multielemental, without sample preparation treatment. Therefore, it aligns well with the principles of green analytical chemistry and provides reliable results for micronutrient determination in compost.

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Water contamination poses serious ecological and public health threats, potentially leading to potable water shortages worldwide. The widespread presence of organic microcontaminants in water resources has become a major international concern, prompting the European Union (EU) to establish a Water Watch List for monitoring these substances. Nowadays, the detection and quantification of these pollutants rely mainly on liquid or gas chromatography coupled with mass spectrometry (LC/GC–MS). Although these methodologies are precise and accurate, they require expensive equipment, experienced technicians, and are not suitable for field analysis or large and fast environment screenings. Therefore, there is a critical need for user-friendly, practical, and portable tools to enable in situ measurements for environmental monitoring.

Surface-enhanced infrared absorption (SEIRA) spectroscopy has great potential for the sensitive and portable detection of microcontaminants. Infrared (IR) spectroscopy is widely used for molecular identification, as it provides detailed information on the vibrational signature of chemical bonds. However, its effectiveness can be limited when dealing with compounds that exhibit weak IR absorption signals or even occur at low concentrations, making the detection of trace amounts of several contaminants difficult. To overcome this limitation, nanomaterials have been explored as amplifiers for SEIRA, allowing the detection of molecules at much lower concentrations.

Cu- and Ag-based quantum dots (QDs) have recently evidenced good optical properties, offering a key advantage of being toxic metal-free. In our group, we successfully optimized the aqueous synthesis of these QDs and demonstrated their potential for SEIRA analysis of organic microcontaminants in water. The use of Ag₂Se and Cu_2-xSe QDs to enhance infrared signatures of organic dyes revealed promising SEIRA results. Our results showed an enhancement factor of 1.8 – 10.9 for Ag₂Se and 1.6 – 9.1 for Cu_2-xSe, for several organic dyes. Furthermore, Ag₂Se QDs were also able to detect the atrazine pesticide in concentrations as low as 0.001 μg/mL. These findings underscore the potential of Ag- and Cu-based QDs as effective nanoplatforms to improve the sensitive detection of organic microcontaminants in environmental monitoring.

Acknowledgements: The authors acknowledge financial support to CNPq, FACEPE, INCTAA, UID Centro de Estudos do Ambiente e Mar (CESAM) + LA/P/0094/2020, and the project NanoSEIRA (COMPETE2030-FEDER-00866600).

Exposure to toxic gases in underground workplaces, such as mines, presents serious risks to worker health and operational safety. Continuous monitoring of air quality—defined by the concentrations of toxic or hazardous gases including CO, CO₂, CH₄, NO, NO₂, SO₂, H₂S, and O₂—is essential to enable rapid hazard mitigation. This requires the capability to detect gas concentrations at trace levels and near real-time.

We present the development of a portable sensing system based on mid-infrared (MIR) absorption spectroscopy, employing quantum cascade lasers (QCLs)—designed and fabricated by Alpes Lasers—as tunable light sources, and substrate-integrated hollow waveguides (iHWGs) to enable robust, compact optical paths optimized for field deployment. The use of laser-based MIR spectroscopy allows for highly selective gas detection over broad concentration ranges, including high concentrations that may saturate or degrade conventional sensors.

The system is designed with special focus on high sensitivity, compactness, and robustness under harsh environmental conditions, including high humidity, dust, mechanical vibrations, and electromagnetic interference. Initial tests showed that gas measurements were not affected by strong vibrational disturbances, such as those caused by nearby rail traffic. In addition, exposure to high humidity conditions was tested without observable degradation in performance.

A user-friendly software interface supports visualization of concentration values and communication with a middleware layer, enabling automated safety alerts when gas concentrations exceed predefined thresholds.

This work is supported by the EU HORIZON 2022 project NETHELIX (No. 101092365).

Keywords: environmental analysis, gas analysis, harsh conditions, mid-infrared, quantum-cascade laser, substrate-integrated hollow waveguide

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Hybrid modelling has recently gained significant attention in the field of machine learning. The concept revolves around integrating a fundamental understanding of biological, chemical, and physical mechanisms with data-driven models. This approach enables the development of hybrid models that utilizes both theoretical knowledge and empirical data, offering a more robust framework for solving complex problems.

In vibrational spectroscopy, hybrid models have been employed for decades to merge principles from chemistry and light scattering with data analysis. These models have been particularly impactful in infrared (IR) spectroscopy, where they are used to effectively address complex scattering and absorption phenomena. One prominent application is in infrared microspectroscopy of cells and tissues, where intricate scattering effects are commonly encountered. In infrared microscopy, the wavelength of electromagnetic radiation is comparable to the size of microparticles and subcellular structures. This size similarity, particularly in the mid-infrared (mid-IR) range (approximately 5–50 µm), gives rise to prominent scattering signatures in the measured spectra. Additionally, the mid-IR region is characterized by strong absorption from most chemicals, making it a rich source of information about the physical and chemical properties of a wide range of samples, including cells, tissues, and microplastics. To extract meaningful information, a key goal is to disentangle chemical absorption effects from optical scattering effects.

The retrieval of pure chemical absorbance spectra from spectra heavily distorted by scattering constitutes an inverse scattering problem. This process involves estimating the optical properties of a sample from its measured spectrum. However, inverse scattering problems are inherently ill-posed, as multiple sets of optical properties can produce the same measured spectrum. Consequently, solving such problems requires strategies to constrain the solution space and reduce ambiguity.

One effective approach involves iterative methods, where solutions are refined by searching within a narrow region close to a known solution, for example, the pure absorbance spectrum of a chemically or biologically similar sample. While these methods can achieve high precision, they are not universally applicable, as they rely heavily on prior knowledge.

In this presentation, we provide an overview of the intricate interplay between scattering and absorption in mid-IR spectroscopy of cells and tissues. We explore a range of methodologies for retrieving pure absorbance spectra and estimating optical properties from scatter-distorted spectra. The approaches discussed span from theory-driven frameworks to purely machine learning-based methods, highlighting their respective strengths, limitations, and potential for advancing the field.

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This work aims to investigate the fate of ablated material during Laser Induced Breakdown Spectroscopy (LIBS) and assess the potential impact on elemental analysis performances on laser ablation based techniques. The competition between atomization and re-condensation at the early stage -immediately after the laser matter interaction- of Laser Induced Plasma (LIP) is discussed with some study cases, investigating the effect of background environment compressibility and the use of plasmonic nanoparticle (NP) during Nanoparticle Enhanced LIBS (NELIBS). On the other hand for exploring the evolution of the LIP material when the plasma is extinguished the particles produced during the LIBS experiment were collected over a large area, spanning several millimeters, and analyzed using High-Resolution Optical Microscopy and Scanning Electron Microscopy. Time-resolved Laser-Induced Plasma images were utilized to interpret the particles distribution, revealing two distinct groups —nanoparticles and microparticles—after plasma extinction. Based on these observations, the effects of plasma condensation, plasma charging, and shockwave transport on the ablated material are discussed. Finally, the impact of re-deposited particles on elemental analysis during LIBS imaging is critically examined.

In this study, Laser-Induced Breakdown Spectroscopy (LIBS) were integrated with Lateral Flow Immunoassays (LFIA) to directly acquire plasma emission spectra from the test line of the LFIA strip for the quantification of selected biomarkers. LFIA is a rapid diagnostic tool based on capillary flow through a nitrocellulose membrane, commonly used in biomedical testing (e.g., pregnancy or COVID-19). LIBS, an optical emission spectroscopy technique based on plasma generation through laser–matter interaction, enables rapid multi-elemental analysis of the irradiated sample area. The sensitivity of LIBS can be significantly enhanced through the use of plasmonic nanostructures—typically metallic nanoparticles (NPs)—with the nanoparticle-enhanced LIBS (NELIBS). This enhancement can amplify the emission intensity by up to two orders of magnitude and enables detection of trace elements down to parts-per-billion (ppb) levels, thus expanding LIBS applicability to biological systems [1, 2]. Therefore, although LFIA is simple and rapid, it lacks quantitative precision and multiplexing capabilities. Coupling it with LIBS overcomes these limitations by analyzing metallic nanoparticles bound to detection antibodies on the test line, enabling simultaneous quantification of multiple analytes.

The main aim of this work is to study the characteristics of laser-induced plasma when antibodies and analyte are on a nitrocellulose membrane, both on the control and test line of LFIA test. This work's specific objective is to identify and quantify exosomes, a subtype of extracellular vesicles (EVs) derived from blood samples. EVs are characterised by the presence of tetraspanin proteins on their membrane surfaces. Two distinct antibodies were conjugated with gold and silver nanoparticles to simultaneously detect and quantify three membrane-associated tetraspanins, enabling multiplex detection on a single test line. (Funded by the European Union - Next Generation EU, Mission 4 Component 1 CUPB53D2302546 0001)

References

[1] M. Dell’Aglio et al, ,Spectrochim. Acta B 155 (2019) 115-122.

[2] M. Dell'Aglio et al, Talanta (2021), 235, art. no. 122741

Laser-Induced Breakdown Spectroscopy (LIBS) has emerged as a powerful tool for multielemental analysis and bioimaging in biological matrices. The applications of LIBS for high-resolution elemental mapping in plant tissues have been studied with the focus on both essential nutrients (e.g., Mg, Ca, K) and toxic heavy metals (e.g., Cd, Pb). The capacity of LIBS to perform rapid, in situ, and simultaneous detection of multiple elements with minimal sample preparation makes it perfectly suited for the study of plant-environment interactions. This work showcases LIBS as a spectroscopic technique capable of resolving elemental distributions within plant tissues under environmental stress conditions such as heavy metal exposure, and emerging treatment strategies, including plasma-treated water. By enabling detailed spatial analysis of nutrient uptake and heavy metal accumulation, LIBS provides critical insights for sustainable agriculture and environmental remediation [1,2].

Looking beyond Earth, the role of LIBS in space exploration has become intensively studied. With its ability to function under variable atmospheric conditions, LIBS is well-suited for deployment in controlled environments such as the Moon or Mars. With the increased scientific interest in space agriculture, it can assist in monitoring plant health, nutrient dynamics, and potential regolith toxicity, and contribute to the development of extraterrestrial life support systems. These applications highlight LIBS not only as a terrestrial diagnostic tool but also as a cornerstone technique in advancing space food production and planetary sustainability efforts.

Acknowledgements:

This work was carried out with the financial support of grant no. 25-18588L (Czech Science Foundation) and the grant no. FSI-S-23-8389 (Brno University of Technology).

References:

[1] L. Čechová et al., "Plasma treatment of water and wastewater as a promising approach to promote plant growth." Journal of Physics D: Applied Physics 58.11 (2025): 115204.

[2] T. Brennecke et al., “Imaging the distribution of nutrient elements and the uptake of toxic metals in industrial hemp and white mustard with laser-induced breakdown spectroscopy,” Spectrochim Acta Part B At Spectrosc, 205, pp. 106684 (2023)

Technological progress over the last decade has in large part been contingent of understanding, designing and controlling materials and devices at ever smaller length scales. As theses length scales keeping going down established analytical chemistry tools end up not being able to resolve them anymore. For example, while mid-IR spectroscopy coupled to an optical microscope is a great tool for rapid chemical imaging at the millimeter and micrometer scale, it relies on the interaction of micron range (2 µm to 20 µm) electromagnetic radiation with the specimen. Hence, the diffraction limit prevents us from building mid-IR optical microscopes that can resolve structures on the nanoscale.

We can circumvent the diffraction limit by building a nearfield imaging system, i.e. by moving the detector and/or the light source as close to our specimen as possible. One approach to move the “detector” closer that has found wide acceptance for mid-IR spectroscopy is to use photothermal expansion induced by a tuneable pulsed laser for detection of local absorption. This PTIR (photothermal induced resonance) or AFM-IR (atomic force microscopy induced resonance) technique reads the local thermal expansion using an AFM tip to enable nanometre scale spatial resolution chemical imaging. AFM-IR can be used to collect mid-IR absorption spectra from nanoscale samples that resemble conventional bulk spectra and it can be used to image the chemical makeup of the sample at nanoscale lateral resolution without the need for labelling or staining .

Within the last decade AFM-IR has found applications across fields and disciplines, from microbiology and medicine to polymer science and material science. AFM-IR has been used to study the secondary structure of peptides in water and to detect a chemotherapeutic at the zeptomole level inside a nanoscale drug carrier . AFM-IR can also be used to determine thermal conductivity and interfacial thermal resistance at the nanoscale.

One of the most exciting aspects of AFM-IR is that it can be used to apply multivariate chemical imaging techniques that are well established for IR microscopy at the nanoscale. These enable to combine information from multiple spectra or multiple single wavelength images into actual maps of chemical composition – if we are doing it right. “Doing it right” requires an understanding of the signal transduction chain in AFM-IR and the peculiarities of scanning probe microscopy. It also requires to understand optical effects that limit the linear range of AFM-IR.

This presentation will discuss the AFM-IR signal transduction chain and which of its parameters can (need to be) controlled to achieve reproducible AFM-IR measurements. Furthermore, our recent research into the AFM-IR signal generation reveals avenues towards improved spatial resolution, sensitivity and even vertical spatial resolution.

Volcano monitoring and hazard assessment can be significantly improved by the real-time study of fine ash in volcanic plumes, which are composed of magma fragments released from volcano's craters during explosive eruptions. Numerous analytical techniques can be applied to obtain the chemical characterization of the juvenile pyroclastic material generated in volcanic plumes. Among them, the most appropriate and easily applied to advanced applications in extreme environments is Laser-Induced Breakdown Spectroscopy (LIBS) [1].

In the initial phase of our study, we present the elemental composition of suspended volcanic ash in air, obtained by a self-calibrated LIBS. Various sizes of volcanic ash samples collected from different sites were suspended in the air by laser-induced shockwaves in a dedicated chamber to replicate the conditions of dispersed volcanic ash in the atmosphere. Simultaneously, a parametric study was conducted to identify the optimal experimental settings for acquiring useful plasma emission spectra for each ash size. The quantitative analysis was then performed via Calibration-Free (CF) LIBS, which is based on the calculation of the spectral radiance of a uniform plasma in local thermodynamic equilibrium [2]. A significant improvement in our analysis method was the inclusion of a CF-LIBS software, which accounts intrinsically for self-absorption. This adjustment is crucial as self-absorption affects the spectral line intensities, leading to an underestimation of the elemental fraction. Another asset to our analytical technique was to deduce the instrument's response from the ash spectrum itself and avoid the necessity for standard calibration lamps. For that, an intensity calibration of the spectra based on the measurements of Fe lines intensities was employed in this work [3]. The results we obtained confirmed the feasibility of real-time elemental analysis measurements of volcanic ash, with a good degree of agreement with the literature composition. Moving forward, we are in the process of developing a portable instrument that can be integrated into drones for in-flight CF-LIBS measurements. New devices have been purchased, such as a small laser, spectrometers that cover a large spectral range and a whole optical system, with the lowest possible weight in order to be mounted on the drone.

Acknowledgement

This study was carried out within the RETURN Extended Partnership and received funding from the European Union Next-Generation EU (National Recovery and Resilience Plan–NRRP, Mission 4, Component 2, Investment 1.3–D.D. 1243 2-8-2022, PE0000005).

References

[1] A. De Giacomo, M. Dell'Aglio, Z. Salajková, E. Vaníčková, D. Mele, P. Dellino, Real-time analysis of the fine particles in volcanic plumes: A pilot study of Laser Induced Breakdown Spectroscopy with Calibration-Free approach (CF-LIBS), Journal of Volcanology and Geothermal Research, Volume 432.

[2] B. Bousquet, V. Gardette, V. Motto Ros, R. Gaudiuso, Marcella Dell'Aglio, Alessandro De Giacomo, Plasma excitation temperature obtained with Boltzmann plot method: Significance, precision, trueness and accuracy, Spectrochimica Acta Part B: Atomic Spectroscopy, Volume 204, 2023, 106686.

[3] A. Taleb, M. Dell’Aglio, R. Gaudiuso, D. Mele, P. Dellino, A. De Giacomo, Self-Calibrated Laser-Induced Breakdown Spectroscopy for the Quantitative Elemental Analysis of Suspended Volcanic Ash, Applied Spectroscopy, 2024, 0(0).

Laser-Induced Breakdown Spectroscopy (LIBS) is an Optical Emission Spectroscopy (OES) technique that relies on the optical analysis of laser-induced plasma (LIP) generated on the surface of a sample. Thanks to its versatility, rapid multielement detection capabilities, and minimal sample preparation requirements, LIBS has found broad application in a range of complex research fields, including geology [1].

The use of LIBS in geological studies typically focuses on two primary areas: qualitative and quantitative analysis. In qualitative applications, the method is employed to determine elemental compositions or to identify and classify different sample types. Achieving reliable classification results requires the development of a comprehensive and well-structured analytical methodology. On the other hand, quantitative analysis involves determining the precise elemental concentrations within unknown samples, which demands rigorous calibration and validation procedures [2].

Both qualitative and quantitative LIBS approaches are highly relevant in terrestrial as well as extraterrestrial geology. In the context of the present research, applications range from building extensive mineralogical libraries based on terrestrial samples to performing quantitative analyses of regolith simulants or meteorite specimens. This work proposes and develops methodologies tailored for these diverse analytical tasks, emphasizing their adaptability for specific geological applications or for broader use across related scientific disciplines.

Acknowledgments

This research was financially supported by the FSI-S-23-8389, and the Czech Science Foundation (23-05186K).

References

[1] J. Buday, J. Cempírek, J. Výravský, P. Pořízka, J. Kaiser, Robust Mineralogy Analysis Utilizing Laser-Induced Breakdown Spectroscopy and Dispersive X-Ray Spectroscopy, in: 2024 IEEE Sensors Applications Symposium, SAS 2024 - Proceedings, Institute of Electrical and Electronics Engineers Inc., 2024. https://doi.org/10.1109/SAS60918.2024.10636561.

[2] P. Pořízka, A. Demidov, J. Kaiser, J. Keivanian, I. Gornushkin, U. Panne, J. Riedel, Laser-induced breakdown spectroscopy for in situ qualitative and quantitative analysis of mineral ores, in: Spectrochim Acta Part B At Spectrosc, Elsevier, 2014: pp. 155–163. https://doi.org/10.1016/j.sab.2014.08.027.

We propose a new method for non-destructive estimation of concrete compressive strength. This method is based on Laser-Induced Breakdown Spectroscopy (LIBS) and multivariate analysis, which allows estimation of compressive strength independent of coarse aggregate distribution. Concrete compressive strength is an important parameter for quality control and durability assessment of concrete. Typically, compressive strength is determined by an uniaxial compression testing. Conventional non-destructive methods using elastic waves have the problem that the measured values vary depending on the measurement location because the wave propagation path changes due to the distribution of coarse aggregates. The method proposed in this study extracts the mortar spectrum by using LIBS to estimate the compressive strength. This method is based on the correlation between the hardness of the mortar and the emission intensity of the spectrum. Principal component analysis and partial least squares regression are used to extract the mortar spectral data from the measured LIBS data and to estimate the compressive strength. This approach is robust to spectral noise. The compressive strength estimated by the proposed method was in agreement with the results of actual compressive strength tests. It is expected that the proposed method will enable rapid, nondestructive and remote measurement of the compressive strength of actual concrete structures in the future.

MicroRNAs (miRNAs) are small, non-coding RNA molecules recognized as promising biomarkers for various diseases. However, detecting them is challenging because they are typically present at very low concentration levels in biological samples, similar in sequence among family members, and susceptible to degradation.

Here, we will provide an overview of a comprehensive, hybrid analytical strategy that significantly enhances the detection and quantification of miRNAs. This approach integrates gold nanoparticle (AuNP)-based signal amplification with advanced separation and spectrometric techniques—specifically asymmetrical flow field-flow fractionation (AF4), multi-angle light scattering (MALS), and inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The method involves designing gold nanoparticles (AuNPs) functionalized with thiolated oligonucleotide probes that specifically hybridize with target miRNAs. This binding enhances optical readouts via plasmonic resonance shifts, offering unparalleled sensitivity and specificity, even in complex biological matrices. AF4-MALS-ICP-MS/MS is employed for precise fractionation and characterization of nanoparticle–miRNA conjugates, providing key information on their hydrodynamic radius, molar mass distribution, and aggregate formation.

Significant improvements in detection limits, down to the low femtomolar range, have been achieved with excellent reproducibility and multiplexing capability. This work paves the way for more sensitive, accurate, and non-invasive miRNA-based diagnostics and offers a blueprint for integrating nanomaterial-assisted detection into high-throughput bioanalytical pipelines.

Chronic exposure to inorganic arsenic is a major concern for millions of people around the world. Severity of health effects induced by arsenic exposure varies with individuals. However, a reliable biomarker of susceptibility has not been established. Detailed characterization of arsenic metabolites could improve understanding of the metabolism of arsenic compounds and its relationships with severity of health outcomes. We report here the separation and detection of twelve arsenic species in human urine using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICPMS). Separation of arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, and up to seven unidentified arsenic species in human urine was achieved within 10 minutes using an anion exchange column and gradient elution. The HPLC-ICPMS method enabled arsenic speciation analysis of more than 1800 urine samples collected from from Araihazar, Bangladesh. Dimethylarsinic acid was the main arsenic species in most of the urine samples although arsenic speciation patterns vary among individuals. Majority of the urine samples had quantifiable inorganic arsenic (99.9% detection rate), monomethylarsonic acid (99.9%), dimethylarsinic acid (100%) and arsenobetaine (98%). Chromatographic peaks of unknown arsenic species were detected in more than 40% of the urine samples. The sum of inorganic and methylated arsenic species was strongly correlated with total urinary arsenic concentration. We also report on the identification of new arsenic metabolites, using HPLC separation with both ICPMS and electrospray ionization mass spectrometry (ESIMS). These results are useful for a better understanding of the relationships between arsenic metabolism and health effects and to for establishing a biomarker of susceptibility to arsenic toxicity.

Mercury (Hg) is recognised as a global pollutant, notable for its presence across various trophic levels. It is considered a bioaccumulative trace element, with the dietary pathway being the primary route of human exposure. Applying silica nanoparticles (SiO₂ NPs) as mitigating agents for heavy metal contamination in crop plants—thereby reducing abiotic stress induced by these contaminants—has shown promising results.

Several mechanisms have been proposed for the mitigation of metal toxicity by silica nanoparticles, including immobilisation in the soil, activation of enzymatic and non-enzymatic antioxidants, chelation and co-precipitation in the soil, and retention or compartmentalisation of toxic elements within the root cell wall.

In this study, we investigate the potential adsorption of Hg by SiO₂ NPs in soybean plant roots, which could lead to the immobilisation of the metal and a reduction in its translocation. To explore the interactions between mercury and silica nanoparticles, we employed analytical techniques such as asymmetric flow field-flow fractionation coupled with multi-angle laser light scattering (AF4-MALS) and single-particle ICP-ToF-MS, which provide complementary and enhanced insights into particle size and composition.

The AF4-MALS-ICP-MS technique enabled the characterisation of the SiO₂ NPs used in this study, identifying particles ranging from 20 to 30 nm in size. This characterisation provided valuable information on the potential mechanisms of action of silica NPs as mitigating agents against heavy metal contamination in soybean plants.

The fractogram correlating Hg and Si signals obtained from ICP-ToF-MS and AF4-MALS showed overlapping signals at the same retention time, suggesting the adsorption of Hg ions by silica nanoparticles. The simultaneous detection capability of ICP-ToF-MS allowed for the monitoring of Hg and Si in root extracts, enabling inferences regarding the elemental composition of the peaks in the fractogram.

The recovery of Hg associated with SiO₂ NPs, as measured by the online AF4/ICP-ToF-MS system, was calculated by integrating the fractogram area. A recovery rate of 94.3% was observed for Hg, demonstrating that the method effectively identified Hg bound to SiO₂ NPs. Area integration also indicated negligible analyte loss through the separation membrane, confirming the method's suitability for characterising the nanoparticles used in this study.

Additionally, metal-targeted metabolomics analyses using ICP-MS/MS and LC-ToF-MS revealed that mercury exposure induces significant alterations in the metabolite profiles of soybean plants. Principal component analysis (PCA) of root samples revealed a clear distinction between the control and Hg-treated groups, with a clustering trend observed between the NP + Hg samples and the control group.

These findings highlight the importance of investigating mercury toxicity and the role of silicon-based compounds (SiO₂ NPs and Na₂SiO₃) as remediation agents in soybean cultivation. This approach can help identify the compounds generated during these processes when applied to nanoparticle-organism interactions.

The Hyphenated multimodal techniques are employed to maximise data acquisition, aiming to extract comprehensive information about the elements of interest. This strategy enables a more detailed understanding of the system under study. The integration of ICP-MS and ESI-MS workflows has shown great potential for detecting and identifying unknown compounds and improving the quantification of suspect or novel analytes in the absence of reference standards. This provides relevant insights in environmental sciences by identifying contaminant species and metabolomics.

Changes in metabolite concentrations reflect the inhibition or activation of specific metabolic pathways, and pathway analysis can offer a broader view of the plant's stress response to contamination. Similarly, supplementing the growth medium with silica may help mitigate the harmful effects of toxic metals on plants. Thus, ICP-MS/MS and LC-ToF-MS-based metal metabolomics demonstrated that mercury exposure in soybean plants leads to significant changes in metabolite profiles. Principal component analysis of root samples clearly distinguished between control and Hg-treated groups, with clustering of the NP + Hg samples closer to the control group.

Coupling digital microfluidics (DMF) with both mass spectrometry (MS) and surface-enhanced Raman spectroscopy (SERS) represents a major advancement in the field of analytical science that combines sample handling and fluidic processing with multimodal chemical detection. DMF enables discrete droplet actuation through electrowetting-on-dielectric, allowing automated and unrestricted processing of nano- to microlitre-sized droplets on a closed chip format. Here, the droplets are moved between two plates to reduce evaporation and contamination. However, this makes chemical analysis of the droplets, which are trapped inside the chip, more challenging. Thus, subsequent analytics are usually carried out offline or with simple optical methods. This work addresses the challenges of coupling DMF with MS and SERS to enable real-time analysis for monitoring chemical and biochemical processes.

We developed an approach that allows on-the-fly mass spectrometric monitoring of chemical reactions in a DMF device, enabled by a chip-integrated microspray hole (μSH) [1]. This technique uses an electrostatic spray ionisation method to spray a portion of a sample droplet through a microhole, allowing its chemical content to be analysed by mass spectrometry. The broad applicability of the developed seamless coupling of DMF with MS was successfully applied to the study of various on-chip organic syntheses, enzymatic reactions as well as protein and peptide analysis. While we could successfully combine on-chip MS-detection and DMF, we also extended the scope for label-free Raman detection [2] for sample transfer from inside the chip to an external insulated SERS substrate. For this purpose, a new electrostatic spray-compatible stationary SERS substrate was developed and characterised for sensitive and reproducible SERS-based measurements and was successfully applied to study an organic reaction occurring in the DMF device, providing vibrational spectroscopic data.

Since the droplet does not get used up in these experiments, making it an inline detection technique, one can carry out further DMF processes with the same reaction mixture droplet. This could be, for example, another chemical reaction step and/or the implementation of a different analytical method at a different location on the same DMF chip, respectively. Therefore, in our recent work, we have enabled dual-mode detection by integrating both of our developed techniques (as mentioned above) within a single digital microfluidic chip. This is achieved by integrating the microspray hole (diameter: 10 μm) and the stationary SERS substrate (diameter: ~1.5 mm) on the top and bottom plate of the DMF chip, respectively. Therein, the performance of the developed system was evaluated to screen and analyse the starting material and product formation of a reaction by MS and subsequently by SERS and vice versa. This also marks the first integration of mass spectrometry and surface-enhanced Raman spectroscopy in a single digital microfluidics device.

Spectral imaging has evolved from a laboratory curiosity into a powerful tool with growing relevance in industrial environments. Rather than capturing traditional RGB-visual images, spectral imaging techniques acquire rich spectral data at each pixel, generating detailed chemical and elemental maps across a sample. Techniques such as Laser-Induced Breakdown Spectroscopy (LIBS), X-ray Fluorescence (XRF), Raman spectroscopy, and Hyperspectral Imaging (HSI) can be used for this purpose, offering complementary insights or validating information regarding sample composition. While LIBS excels at detecting light elements with high spatial resolution, XRF delivers quantitative bulk analysis, Raman reveals surface-level molecular structures, and HSI captures subtle material variations based on molecular signatures, enabling rapid scanning of large surface areas.

When integrated, they enable smarter decision-making in areas ranging from resource exploration to production-line quality control.

In this talk, we explore how our lab implements these advanced spectral techniques, across industrial contexts: directly on-site for raw materials exploration in mining environments; at-line for heavy metal screening in recycled wood processing and quality inspection in the cork industry; and now in-sight, where digital and augmented reality frameworks are used to offer enhanced interpretation and decision support for lithium exploration.

This presentation highlights advances in vibrational spectroscopic imaging, with a focus on the application of the optical photothermal infrared (O-PTIR) technique for the high-resolution analysis of polymer microstructures. O-PTIR enables submicron lateral resolution and allows for the simultaneous acquisition of IR and Raman spectra from the exact same sample location — overcoming the diffraction-limited resolution of conventional FT-IR imaging and the spatial mismatch issues in separate Raman and IR measurements.

We demonstrate the capabilities of this technique through the spectroscopic imaging of synthetic polymers and phase-separated biopolymer blends. These blends are increasingly important due to the rising demand for biodegradable alternatives to conventional plastics. However, the physical properties of biopolymers often require optimization through blending, which can lead to phase separation. Mapping this spatial segregation is essential for understanding and improving material performance.

By combining submicron IR and Raman imaging in a single, co-localized measurement, O-PTIR provides deeper insight into the structural and chemical heterogeneity of polymeric systems. The instrumentation and methodology presented mark a significant step forward in characterizing complex materials at previously inaccessible spatial scales.

Waste management is fundamental for minimizing environmental impact and preserving resources, and circular economy models are essential in this context. Accurate material identification and classification are necessary for optimizing recycling processes. Moreover, sorting materials effectively enhances both the efficiency and sustainability of recycling systems.

Recently, space agencies have increased interest in waste minimization and in recycling materials generated in space, since the accumulation of space debris poses significant risks to ongoing and future space missions. Space waste is primarily composed of materials such as polymers, metals, foams, technical textiles, and electronic components, which, at the end of their useful life, contribute to the growing mass of debris in Earth orbit. This highlights the pressing need for efficient and sustainable waste management systems, grounded in circular economic principles, to address the escalating problem of space-generated waste. Such systems are essential not only for mitigating the risks they pose to future missions but also for reducing the environmental footprint of space activities. Identification, classification and/or sorting of these materials is critical for developing efficient recycling technologies, enabling the selection of appropriate equipment to handle different waste types, such as plastics, metals, and complex composite materials. Given the challenges of performing material analysis in space, where traditional sample preparation techniques are often impractical, Hyperspectral Imaging (HSI) in the Near Infrared (NIR) range presents a powerful, non-invasive solution. HSI allows for quick, accurate analysis of materials in real-time without requiring physical contact or sample preparation.

This study explores the use of two distinct illumination sources, LED and Halogen Light, for hyperspectral data collection to classify space-derived waste materials such as foams, technical textiles, and plastics, while also comparing their performance. These materials, commonly found in space applications, contribute significantly to the space debris problem, making their accurate classification a priority for future space waste management strategies. Data were captured using a NIR Spectral Camera™ (Specim, Finland) and an ImSpector N17E™ imaging spectrograph. The raw spectral data were processed with advanced algorithms to reduce noise and improve differentiation, facilitating the analysis of different waste types.

Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) were applied to explore the data and then classify the materials based on spectral signatures. The research explores the potential of using LED and Halogen illumination to effectively support material classification through HSI, with each light source offering unique advantages depending on the specific application: LED lighting is particularly beneficial in scenarios that demand energy efficiency and stability, while Halogen illumination is more suitable in contexts where a broader spectral range is crucial for accurate material differentiation.

This research is carried out within the framework of the "Sustainable Technologies for Circularity Valorization" (SUSTAIN) project, a spin-off and phase 2 continuation of the "Hyperspectral Based Sensing Architectures for Resource Circularity" (H-SPACE) initiative, funded under the Italian PNRR program, aiming to develop technologies that improve space waste management and promote to the circular economy in space.

The findings suggest that HSI, combined with tailored illumination, holds significant potential for advancing space waste recycling by enabling precise and efficient classification of materials. This approach not only supports the sustainable management of space-derived waste but also lays the groundwork for future innovations in hyperspectral imaging, contributing to a more sustainable and resource-efficient future for space industries.

The progress of vibrational microspectroscopy systems has developed rapidly with the availability of compact, reliable laser sources such as Interband Cascade Lasers (ICL), Quantum Cascade Lasers (QCL) and extremely broad tuning External Cavity Quantum Cascade Lasers (EC-QCL). The are commercially available since more than twenty years. Since about a decade EC-QCL based microspectroscopy systems deliver disruptive results in digital pathology for the diagnose of cancerous tissue in measurement times up to 170 times Faster than Fourier-Transform Infrared spectrometer microscopes (µFTIR). The throughput of QCL-IR far-field microscopes fit into the common time slots of clinical routines, while the measurement times of µFTIR do not fulfil this requirement.

Here we present a feasibility study of simultaneously imaging the morphology and the related metabolism of microbiological specimen clusters on different materials under changing environmental conditions. This includes drying of bacterial cultures and its reaction to different treatments. The measurement time of less than one minute is short enough to regard the sample as stable during measurement.

Heavy metal contamination in rivers is one of the most concerning environmental issues worldwide due to its impact on ecosystems, public health, and national economies. In Mexico, a notable case occurred in 2018 involving the mass mortality of the manatee (Trichechus manatus) in the state of Tabasco, with the municipality of Macuspana being the most affected. This species, classified as endangered under NOM-059-SEMARNAT-2010, inhabits freshwater bodies such as the Bitzal River.

This study aims to investigate the presence of metals and metalloids in the Bitzal River through the analysis of water, sediment, and vegetation samples. Samples were collected at 13 sites in 2018 and at 16 sites in 2024 to determine the concentration of these elements and assess their potential impact on the ecosystem. Comparing both periods allows for the identification of temporal variations in contaminant presence and their possible association with the degradation of the manatee's habitat. Elemental analysis of water, sediment, and vegetation samples was carried out using inductively coupled plasma optical emission spectrometry (ICP-OES) with a PerkinElmer Avio 500 system.

The chemical preparation of water samples involved filtration and subsequent acidification with ultra-high purity nitric acid (HNO₃). For sediment samples, acid digestion was performed using a MILESTONE-MLS microwave digestion system, following the NOM-147-SEMARNAT-SSA1-2004 standard, with a 9:3 mixture of HNO₃ and hydrochloric acid (HCl). Vegetation samples were subjected to microwave-assisted acid digestion using a 9:3 mixture of HNO₃ and hydrogen peroxide (H₂O₂), both of ultra-high purity.

To ensure analytical quality, certified reference materials were used: Montana Soil II NIST® SRM® 2711a for sediments and Certified Reference Material Orchard Leaves (Cat. #CRM-OL) in 4% HNO₃ for vegetation. Data processing and analysis were performed using Syngistix software for ICP. The detection limits achieved by ICP-OES were suitable for assessing compliance with regulatory standards, and recovery rates of reference materials ranged from 80% to 120%.

The results indicate that most metal concentrations in sediment samples from both 2018 and 2024 did not exceed the limits established by current Mexican regulations. However, in the 2024 samples, vanadium (V) exceeded permissible levels at all 16 sampling sites. Furthermore, when compared to international reference values such as the Canadian Environmental Quality Guidelines (CEQG) and the National Oceanic and Atmospheric Administration (NOAA) standards, arsenic (As), nickel (Ni), lead (Pb), and zinc (Zn) exceeded allowable concentrations in all analyzed sites in 2024. The average concentrations of metals and metalloids (mg/kg) in 2018 were as follows: arsenic (As) 17.8 > zinc (Zn) 12.3 > lead (Pb) 5.9 > vanadium (V) 3.4 > nickel (Ni) 1.05. In contrast, significantly higher concentrations were recorded in 2024: vanadium (V) 523.0 > nickel (Ni) 285.5 > zinc (Zn) 117.1 > lead (Pb) 8.2 > arsenic (As) 3.7. In vegetation samples, vanadium (V) was the only quantifiable element.

Statistically, metal concentrations in sediments in 2024 showed a significant increase compared to those from 2018. This rise suggests a possible intensification of contamination, potentially attributable to increased anthropogenic sources, land-use changes, or alterations in local environmental conditions. Regarding water analysis, the average concentrations in 2018 (mg/L) were: arsenic (As) 0.013 > zinc (Zn) 0.011 > nickel (Ni) 0.009 > chromium (Cr) 0.008 > lead (Pb) 0.002. In 2024, the following concentrations were observed: cadmium (Cd) 0.008 > arsenic (As) 0.008 > lead (Pb) 0.008 > chromium (Cr) 0.008 > copper (Cu) 0.007 > nickel (Ni) 0.004 > zinc (Zn) 0.001.

Preliminary conclusions indicate a significant increase in the concentration of elements in water, sediments, and vegetation between 2018 and 2024, particularly for vanadium (V) and nickel (Ni).

The development of oil facilities near natural areas has a significant impact on ecosystems, often serving as sources of heavy metals and metalloids. These substances accumulate in high concentrations, particularly in sediments (Pejman et al., 2015). Mangrove ecosystems act as natural barriers, mitigating erosion and damage caused by storms and hurricanes.

In the study area (Paraiso, Tabasco), an oil refinery was constructed in 2023 and is set to begin operations in 2025. The Aquiles Serdán Ejido, where the mangrove ecosystem is located, lies within the refinery's area of influence. This study aims to assess the current levels of heavy metals and metalloids in sediment samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was employed for analysis, coupled with an ultrasonic nebulizer to enhance detection limits.

A total of 90 soil and sediment samples were collected from four distinct zones. Sample preparation involved a Milestone microwave oven, model MLS1200 Ultra, with high-pressure Teflon vessels following the EPA 3051A method. Each sample was digested using 7 mL of nitric acid and 3 mL of hydrochloric acid, then diluted to 50 mL with deionized water. The Montana Soil SRM 2710a was used as the reference material. For the determination of heavy metals and metalloids (As, Cd, Co, Cu, Cr, Ni, Pb, Sb, V, Zn) in sediments, ICP-OES (Avio 500 model, Perkin Elmer®) was utilized. Instrumental conditions included a plasma flow rate of 10 L/min, an auxiliary gas flow rate of 0.2 L/min, and a nebulizer flow rate of 0.5 L/min using an ultrasonic nebulizer (CETAC, model U5000AT+). Detector integration time was set to 10 seconds with three replicates per sample. Detection limits for ICP-OES were 3.2, 0.1, 0.2, 0.5, 0.4, 0.5, 1.9, 1.2, 1.8, and 5.7 μg/L for As, Cd, Co, Cu, Cr, Ni, Pb, Sb, V, and Zn, respectively. Calibration standards included Quality Control Standard 7 and Quality Control Standard Pure 21 from Perkin Elmer®. The recovery percentages of SRM 2711a for As, Cd, Co, Cu, Cr, Ni, Pb, Sb, V, and Zn were 81.04, 88.3, 68.13, 90, 81.62, 91.46, 81.72, 56.38, 63, and 90, respectively. Detection limits achieved using the ultrasonic nebulizer coupled to ICP-OES were superior to those achieved with conventional GemCone nebulizers from Perkin Elmer. The results revealed the presence of Cr (42.66–216.19 mg/kg) as the most abundant element. Other notable elements included vanadium V (36.65–102.37 mg/kg), Zn (42.06–103.87 mg/kg), Ni (13.86–78.20 mg/kg), and Cu (6.84–38.53 mg/kg). Elements found in lower concentrations include As (1.84–2.77 mg/kg), Co (4.74–8.44 mg/kg), and Pb (2.15–8.40 mg/kg). These findings are consistent with the decreasing order of mean concentrations reported by Guo et al. (2023) in mangrove sediments from Dongzhai Harbor, South China. Both studies exhibit similar patterns in the distribution and concentration of heavy metals, particularly Cr and Zn, which could be attributed to comparable anthropogenic influences such as petrochemical and urban industrial activities affecting soil and sediment composition.

1. Pejman, A. H., Bidokhti, A. A., Riahi Bakhtiari, A., & Ardestani, M. (2015). Fractionation of heavy metals in sediments and assessment of their availability risk: A case study in the northwestern Persian Gulf. Marine Pollution Bulletin, 93(1-2), 282-290.

2. Guo, Y., Ke, X., Zhang, J., He, X., Li, Q., & Zhang, Y. (2023). Distribution, Risk Assessment and Source of Heavy Metals in Mangrove Wetland Sediments of Dongzhai Harbor, South China. Int. J. Environ. Res. Public Health 2023, 20, 1090.

The thermal hydrogenation of carbon dioxide (CO₂) to formic acid and other value-added products represents a significant opportunity for sustainable chemical synthesis. Achieving efficient CO₂ conversion and product selectivity, however, critically depends on the development of suitable catalysts [1]. In particular, the design of cost-effective catalytic (nano)materials capable of replacing noble metal-based systems remains a major research focus. In recent years, our group has developed green electrochemical routes for the synthesis of nano- and micro-structured materials, offering a sustainable alternative to conventional wet-chemical and precipitation methods. These electrochemical strategies have demonstrated considerable advantages, including operational simplicity, high yields, and precise control over particle size, morphology, and composition [2].

Among these approaches, sacrificial anode electrolysis in alkaline media has been successfully employed to synthesize Zn-based materials with tunable physicochemical properties. By varying synthetic parameters such as current density and stabilizer composition, we have achieved control over material morphology and phase composition [3]. Here, we report the electrochemical synthesis of (supported) bifunctional Cu/ZnO catalysts using this method. Special attention is given to the role of support materials, specifically zeolites and biopolymeric matrices, which may influence dispersion, stability, and catalytic behavior. The resulting materials have been characterized using a set of advanced spectroscopic and microscopic techniques, including transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and dynamic light scattering (DLS), to elucidate structural, surface, and compositional features. Preliminary catalytic evaluations for CO₂ hydrogenation reactions indicate promising activity and selectivity, underscoring the potential of these electrochemically-derived materials. Comparison with literature-reported catalysts synthesized via conventional routes highlights the advantages of our electrochemical method in terms of environmental sustainability, morphological control, and catalytic performance. This work highlights that electrochemical synthesis is a versatile way for designing next-generation CO₂ hydrogenation catalysts and provides insights into the role of material architecture and support effects on catalytic functionality.

1. M. Aktary et al., Chem. Asian J. 2024, 19, e202301007. doi: 10.1002/asia.202301007.

2. M Izzi et al., ChemElectroChem 2023, 10, e202201132. doi: 10.1002/celc.202201132.

3. M. Izzi et al., ACS Applied Nano Materials 2023, 6, 10881–10902, doi: 10.1021/acsanm.3c01432.

Research funded by European Union - Next Generation EU, Mission 4 Component 1. CUP F93C24000420006 – “MACACO” project.

Integrating photoredox-active and catalytically functional units within a single molecular framework is highly desirable. In this context, bridging ligands that incorporate alkyne groups provide an excellent platform for facilitating efficient photoinduced electron transfer in light-driven catalysis based on ruthenium polypyridyl complexes. However, the inherent reactivity of alkynes under light exposure necessitates strategies to protect these ligands.[1] One promising approach involves embedding the heterodinuclear photocatalyst within a soft-matrix protective macrocycle.

Our focus is to investigate the light-induced multi-electron charge transfer of a Ru–Rh dyad encapsulated within a cucurbit[7]uril ring, forming a novel supramolecular rotaxane photocatalyst. This system is aimed at advancing efficient biomimetic photocatalysis, such as the reductive hydrogenation of NAD⁺. For characterization we employ a set of spectroscopic tools such as time-resolved spectroscopy and resonance Raman spectroelectrochemistry to analyze the light-induced formation and the properties of charge-separated states during multiple electron transfer from the photosensitizer to the catalyst. We pay particular attention to the promising influence of the protective macrocycle with respect to its prevention of potential deactivation pathways.

Acknowledgments

Funding by the Deutsche Forschungsgemeinschaft (German Research Foundation) via the TRR CATALIGHT, Projektnummer 364549901, TRR 234, A1 & C3.

References

[1] Zedler, L., Wintergerst, P., Mengele, A.K., Rau, S. et al., Nat Commun 13, 2538 (2022).

Current quality control techniques in the pharmaceutical industry (e.g. chromatographic methods) require a high amount of organic solvents, are time consuming and do not work with every sample. A greener alternative method is the use of infrared (IR) methods to quantify active ingredients in pharmaceuticals.[1]

In the present study, our team was able to quantify urea in wool alcohols ointment using infrared attenuated total reflection spectroscopy (IR-ATR) in combination with multivariate data analysis, in particular principal components analysis (PCA) and partial least squares regression (PLS-R). Calibration and validation were performed with a total of 108 samples and the PLS-R model was subsequently tested with unknown formulations to proof its reliability.

This approach offers a viable alternative to conduct ring trials usually performed using high performance liquid chromatography (HPLC) methods orchestrated by Central Laboratory of German Pharmacists. HPLC is used despite its high environmental impact, particularly when analyzing lipophilic compounds that require a large amount of organic solvents.[2] In contrast, using the described IR-ATR method, the amount of organic waste is reduced and in general simplifies the sample preparation and is non-destructive.

Furthermore, the low-cost, high-speed, and ease-of-use make this method particularly suitable for in-house quality control in pharmacies, where access to advanced analytical instrumentation is often limited.[3]

The integration of IR-ATR spectroscopy with multivariate data analysis represents a sustainable, accessible, and scalable solution for routine quality control of topical formulations and supports broader adoption of green analytical chemistry principles in pharmaceutical practice.

References:

1. Schlegel, L. B., Schubert-Zsilavecz, M. & Abdel-Tawab, M. Quantification of active ingredients in semi-solid pharmaceutical formulations by near infrared spectroscopy. Journal of Pharmaceutical and Biomedical Analysis 142, 178–189 (2017).

2. Gaber, Y., Törnvall, U., Kumar, M. A., Ali Amin, M. & Hatti-Kaul, R. HPLC-EAT (Environmental Assessment Tool): A tool for profiling safety, health and environmental impacts of liquid chromatography methods. Green Chem. 13, 2021 (2011).

3. Lichtblau, V. & Plener, H. Qualitätssicherung dermatologischer Rezepturen in der Apotheke. Maßgeschneiderte Arzneimittel – patientenfreundlich und sicher. Pharmazie in unserer Zeit 39, 300–305 (2010).

Photochemical vapor generation (PVG) is a highly efficient sample introduction technique increasingly used in analytical atomic spectrometry for determination various elements, including some platinum group metals. However, our understanding of their PVG reaction mechanisms is limited, primarily due to a lack of information about the identities of their volatile species. The majority of the volatile species generated by PVG have been convincingly identified using gas chromatography mass spectrometry (GC-MS), however, this approach has not been successful in identifying the volatile species of Ru, Os, and Ir generated under reductive PVG conditions resulting from UV photolysis of HCOOH, despite their high PVG efficiencies1,2. Regarding their potential volatile species, it can be assumed that UV photolysis of HCOOH media can only produce hydrided/carbonylated metal compounds with the general formula Mx(CO)yHz, provided that the 18-valence electron rule is satisfied.

In this study, a direct analysis in real time (DART) ion source connected to an Orbitrap high-resolution mass spectrometer (HRMS) was used for identification of volatile species of Ir. It was generated using a thin-film flow-through photoreactor and a flow injection (FI) sample introduction from the photochemical media that contained either diluted or concentrated HCOOH, possibly spiked with Co2+, and/or Cd2+ as mediators2,3. The DART-HRMS spectra were recorded in both positive and negative ion modes at a resolution of 120 000 (at 200 m/z). The identification of Ir ions was facilitated by observing a characteristic FI peak profile at any m/z window and characteristic isotopic pattern of Ir (37.3% for 191Ir and 62.7% for 193Ir), and by accurate mass determination.

Initial experiments using nitrogen (N2) as the discharge gas revealed extensive structural transformations within the DART ion source, including notable decarbonylation, hydration, oxidation, and the formation of nitrogen-containing ions. Key parameters, such as discharge gas temperature and transfer tube temperature, were optimized to balance analyte ion sensitivity and minimize structural alteration. Using 10 M HCOOH as the photochemical medium with the addition of 50 mg L–1 Cd2+ as the mediator, the most abundant ions detected in the positive ion mode were [C3H4O6Ir]+ (100%), [C2H4O5Ir]+ (42%), [C3H5O5NIr]+ (42%), and [C2H4O3NIr]+ (23%). Additional ions with lower abundances, such as [C4H2O6Ir]+ (9.2%) and [C4H5O6NIr]+ (6.9%) likely indicate the presence of four CO groups. In the negative ion mode, the most abundant ions were [O2Ir]– (100%), [O3Ir]– (36%), [CH2O2Ir]– (15%), and [C2O3Ir]– (14%). Employing argon (Ar) as the discharge gas reduced fragmentation and oxidation processes, likely due to its "softer" ionization properties, resulting in more straightforward structural characterization, especially in the negative ion mode. Using 0.01 M HCOOH with the addition of 5 mg L–1 Cd2+ as a mediator, the most dominant ions were [O2Ir]– (100%) and [O3Ir]– (60%) again, but these were followed by [C3O3Ir]– (26%), [C2O3Ir]– (11%), and [C4O4Ir]– (6.4%). The latter ion, likely corresponding to Ir(CO)4–, was the one with the highest m/z detected with a significant relative intensity and confirmed that the volatile species was mononuclear Ir carbonyl. With respect to the 18-valence electron for stable transition metal carbonyls, it is reasonable to assume that the volatile species is Ir(CO)4H.

Thus, the DART-HRMS appears capable of identifying some unstable volatile metal carbonyl species, which are difficult to identify using traditional GC-MS techniques and can be used for identification of other unknown volatile species of transition metals generated during PVG.

Reference:

(1) E. Pagliano et al., J. Anal. At. Spectrom. 2022, 37 (3), 528–534.

(2) S. Musil et al., Anal. Chem. 2023, 95 (7), 3694–3702.

(3) E. Jeníková et al., Anal. Chem. 2024, 96 (3), 1241–1250.

Photochemical vapor generation (PVG) under UV irradiation is an emerging sample introduction technique offering enhanced sensitivity and reduced matrix interferences in inductively coupled plasma mass spectrometry (ICP-MS). This study explores the UV-PVG of silver (Ag) and gold (Au) from acidic aqueous solutions, focusing on the nature of the volatile species formed and their efficient transport to the plasma.

Using a low-pressure mercury lamp as the UV source, Ag and Au were exposed to formic acid and other photoreductants to initiate vapor generation. The volatile species generated were directed to ICP-MS for quantitative analysis. Experimental variables such as acid type and concentration, photolysis time, and matrix effects were systematically optimized. The PVG efficiency was found to be highly dependent on the redox chemistry of the metal precursors.

Preliminary evidence suggests the formation of ultra-fine particulate species, possibly metal nanoparticles (NPs), as key carriers in the vapor phase. While the generation of classical molecular species (e.g., hydrides) could not be confirmed for Ag and Au, the volatility and transport efficiency under UV conditions point toward a nanoparticle-mediated mechanism. However, definitive identification of these species remains a subject of ongoing investigation, involving off-line trapping and characterization techniques.

These findings contribute to a deeper understanding of PVG mechanisms for noble metals and support the development of reagent-efficient, green methodologies for trace-level analysis of Ag and Au by ICP MS.

Gastric cancer remains a leading cause of cancer-related mortality, requiring the urgent development of innovative diagnostic tools for early detection. This study presents an integrated infrared spectroscopic electronic nose system, a novel device that combines infrared (IR) spectroscopy and electronic nose (eNose) concepts for analyzing volatile organic compounds (VOCs) in exhaled breath. This system was calibrated using relevant gas mixtures and then tested during a feasibility study involving 26 gastric cancer patients and 32 healthy controls using chemometric analyses to distinguish between exhaled breath profiles. The obtained results demonstrated that the integration of IR spectroscopy and eNose technologies significantly enhanced the accuracy of VOCs fingerprinting via principal component analysis (PCA) and partial least-squares-discriminant analysis (PLS-DA). Distinct differences between the study groups were revealed with an accuracy of prediction of 0.96 in exhaled breath samples. This combined system offers a high sensitivity and specificity and could potetially facilitate rapid on-site testing rendering the technology an accessible option for early screening particularly in underserved populations.

Exhaled breath, which contains gases, volatile organic compounds (VOCs), and aqueous microdroplets, has emerged as a promising matrix for the non -invasive detection of lung diseases, including Covid-19. During the onset or recovery phases of illness, various biochemical processes release gases and VOCs into the bloodstream, which can then diffuse into the lung alveoli and be detected in exhaled breath. A viable strategy for detecting these compounds involves using photoluminescent (PL) materials that respond to VOCs through measurable emission changes.

In this context, we synthesized a novel lanthanide complex, 3NH4[Tb(HPMIDA)2(H2O)] (HPMIDA=desprotonated N-(Phosphonomethyl)iminodiacetic acid), and characterized it with a serie of techniques, among them single-crystal X-ray diffraction. TbHPMIDA exhibits a unique arrangement of phosphonate -OH groups, which could promote effective chemical on the substrate such as commercial SiO2 glass.

Photoluminescence studies demonstrated the material's strong response to specific VOCs, particularly acetone and limonene, which are linked to hyperglycemia (e.g., diabetes) and chronic liver diseases, respectively. The PL intensity showed a linear correlation with VOC concentration, indicating potential for quantitative detection. The interaction between TbHPMIDA and acetone is presumed to occur via reversible hydrogen bonding, as supported by powder X-ray diffraction results.

Successful substrate functionalization was confirmed, and changes in the excitation profiles suggest new interactions between the complex and the substrate. Using a custom gas cell, we evaluated the PL response of the functionalized glass substrate (3 × 3 mm) under acetone exposure, confirming its sensitivity. To further reduce the quantification limits and enhance selectivity, a miniaturized gas cell is being developed. The integration of mid-infrared (MIR) detection in this system could significantly improve molecular discrimination and analytical performance.

Acknowledgements:

Thanks to The São Paulo Research Foundation (FAPESP) for inancial support under grants # 2023/07987-7, 2025/01390-4 and 2021/08111-2. Also thanks to National Council for Scientific and Technological Development (CNPq) for funding this research under grant # 304718/2023-8.

Here we present our latest advancements and achievements in design of fiber optic probes for ultraviolet (UV), visible, near-infrared (NIR), Raman and mid-infrared (MIR) spectroscopy. We developed and tested reflection probes with low straylight and protective window to be used for different applications. These probes specially designed for FTIR and diffraction grating NIR spectrometers.

Robust fiber optic probes enable remote process control at harsh conditions in petrochemical, pharmaceutical and food industries instead of time consuming and expensive sampling which makes process control in-line impossible. Fiber spectroscopy eliminates the need in sample preparation and allows real-time, in-line monitoring of chemical compositions and process parameters, resulting in significant benefits for industrial production due to its increased efficiency, reduced waste, process time, improved product quality and process safety. In particular, fiber optic probes utilizing UV, visible, NIR, and MIR spectroscopy help to detect a wide range of chemical components, making them ideal for the analysis of complex mixtures in different applications: in liquids, powder or even gas media flow. In addition to their ability to monitor processes in real-time and perform measurements in harsh or hazardous environments, fiber-optic probes are lightweight and portable, making them suitable for use in both laboratory and industrial settings. Moreover, combination of several spectroscopic techniques in one combi-probe gives a synergetic effect resulting in better accuracy of measurements. Overall, the adoption of fiber optic probes utilizing UV, visible, NIR, and MIR spectroscopy gives significant advancements in the petrochemicals, pharmaceuticals, foods, and feeds industries, leading to more efficient and cost-effective production processes

The detection of cannabidiol (CBD) at trace levels in complex commercial beverage matrices presents a significant analytical challenge due to molecular interference and signal attenuation. In this study, we employed surface-enhanced infrared absorption (SEIRA) spectroscopy for sensitive and selective identification of CBD in diverse beverage samples including coffee, tea, beer, and sparkling water.

To enhance spectral response, we developed hybrid sensing platforms incorporating chemically reduced graphene oxide (rGO) and compared their performance against commercially available thin (1–4 layers) graphene nanoplatelets. The rGO substrates exhibited notable signal enhancement and high reproducibility. The rGO improved detection capabilities at parts-per-million (ppm) levels surpassing conventional FTIR and commercial graphene-SEIRA performance.

Density Functional Theory (DFT) simulations provided theoretical validation for observed vibrational modes, enabling accurate molecular fingerprinting of CBD. Furthermore, X-ray photoelectron spectroscopy (XPS) was employed to elucidate the enhancement mechanism associated with rGO-CBD interactions.

Our findings confirm the robustness and sensitivity of the proposed rGO-SEIRA platform, offering a promising tool for real-time and non-destructive analysis of CBD in beverages. This versatile approach holds potential for applications in pharmaceutical quality control, forensic analysis, and commercial product authentication.

Laser-based mid-infrared (mid-IR) sensors (e.g., quantum cascade lasers - QCLs) offer high sensitivity and chemical specificity for detecting chemical species in aqueous and marine environments [1–3]. While such systems can readily detect water-soluble inorganic species, monitoring poorly water-soluble organic compounds, such as polycyclic aromatic hydrocarbons and pharmaceutical residues, requires surface enrichment strategies to achieve sufficient sensitivity [4]. Polymer-modified sensing interfaces, particularly in attenuated total reflectance (ATR) and fiber-optic evanescent wave (FEW) configurations, have been widely adopted to enhance the detection sensitivity of such analytes. In this context, thin polymer layers are applied to the sensor waveguide to preconcentrate analytes of interest (AOIs )[5–7].

Although many polymers have been proposed for aqueous and marine applications [4], prolonged water exposure introduces significant challenges, including polymer swelling, water ingress, and morphological degradation, all of which directly impact long-term sensor functionality [8]. In order to use these polymer-based IR sensor types in-field (e.g. marine conditions) within prolonged measurement campaigns (e.g. 30 days or more), the enrichment layers must not only concentrate AOIs effectively, but also maintain spectroscopic integrity under continued aqueous exposure.

In this study, six polymers, including polyisobutylene (PIB), polydimethylsiloxane (PDMS), polyethyleneimine (PEI), polystyrene-co-butadiene (PSCB), poly(acrylonitrile-co-butadiene) (PAB), and poly(methyl methacrylate) (PMMA) were investigated for their swelling behaviour, spectral stability, and morphological resilience. ATR-FTIR spectroscopy was used to monitor in situ spectral changes over a 24-hour immersion of the polymer in Milli-Q and artificial seawater. Swelling was observed in the more hydrophilic polymers, leading to unstable sensor backgrounds in the water vibration region, baseline drift, and a reduced polymer signal after drying, indicative of partial dissolution or detachment of the polymer layer. In contrast, PIB, PSCB, and PAB exhibited minimal water uptake, showed consistent spectral profiles and remained attached on top of the ATR substrate surface.

To asses long-term morphological changes, atomic force microscopy (AFM) [9] was used to characterize polymer-coated silicon wafers before and after immersion for 5, 10 and 30 days in both Milli-Q and seawater. Surface roughness and topographical features were analyzed to quantify film integrity and degradation over water exposure. Initial AFM scans revealed notable coating inhomogeneities: although most surface regions exhibited localized surface elevations between 200 and 900 nm, isolated features reaching up to 4 µm in height were detected for PSCB and PAB, indicating incomplete uniformity during deposition. Upon immersion, PIB and PAB films showed progressive surface degradation, including dissolution of thinner regions and expansion of surface defects. In contrast, PSCB maintained topographical consistency over 30 days, with no significant increase in roughness or evidence of delamination, identifying it as the most morphologically robust polymer film. These experimental observations were further supported by molecular dynamics simulations, which demonstrated that PSCB exhibits the highest resistance to water penetration among the tested polymers.

Combined spectroscopic, morphological, and computational characterization revealed the key degradation mechanisms affecting polymer coatings under prolonged marine exposure and established essential selection criteria for enrichment materials suitable for sustained deployment in laser-based IR sensors targeting particular AOIs.

This work presents a multidisciplinary study combining experimental infrared (IR) fiber-optic sensing and quantum mechanical modeling to optimize the detection of metoprolol in aqueous solution using an AgX optical fiber functionalized with a MOF-808/PVA composite. MOF-808, based on zirconium-oxo clusters and benzene tricarboxylate linkers, was selected for its high porosity and affinity for organic analytes. Its vibrational signature and interaction modes with metoprolol were initially explored using DFT calculations, enabling the identification of key IR-active bands and potential binding configurations. To develop the sensing platform, a 5 cm cylindrical AgX optical fiber (500 µm diameter) was coated with a thin film of MOF-808 dispersed in polyvinyl alcohol (PVA). The PVA matrix served to improve film homogeneity, mechanical adhesion to the fiber, and partial water compatibility, while preserving MOF porosity and enabling diffusion of metoprolol molecules. The functionalized fiber was tested in aqueous metoprolol solutions using quantum cascade laser (QCL) spectroscopy in the 1525–1840 cm-1 range. Despite strong water absorption in this region, pre-processing by water background subtraction and chemometric analysis (PLS regression) allowed the extraction of metoprolol-specific signals. Theoretical calculations support experimental investigation, notably in the aromatic and amide-like vibrational regions. This study aims to establish the synergistic role of MOF-808 and PVA in creating a sensitive and stable fiber-optic IR sensor for pharmaceuticals in water. Parallelly, it also presents a unique way to computationally guide vibrational assignments and interpreting weak or buried signals in complex aqueous environments.

Toxic gases in confined environments like mines pose serious risks to health and safety. We present a compact, portable sensing system for real-time monitoring of hazardous gases (CO, CO₂, CH₄, NO, NO₂, SO₂, H₂S, O₂) using mid-infrared absorption spectroscopy.

The system integrates quantum cascade lasers (QCLs) and substrate-integrated hollow waveguides (iHWGs) for selective, trace-level detection across broad concentration ranges—even where conventional sensors fail. Designed for harsh conditions, it operates reliably under high humidity, dust, vibrations, and electromagnetic interference.

This work is supported by the EU HORIZON 2022 project NETHELIX (No. 101092365).

Green Analytical Chemistry, i.e. the assessment and consideration of environmental, energy and safety aspects, is increasingly becoming part of the overall evaluation of analytical methods [1]. This has led to a new focus on the development and research of improved analytical methods that are more sustainable or 'greener'. Simplified sample preparation such as suspensions and partial digestions for trace element determination by total reflection X-ray fluorescence (TXRF) in various biological samples have been published previously [2,3]. However, matrix- or salt-rich samples such as culture media can affect performance and therefore complicate sample preparation. In this case, sample deposition by nanoliter dispensers can reduce the formation of salt crusts compared to conventionally prepared sample carriers [4].

The aim of this study was the determination of iron and further trace elements in archaea in a simple, green way. First, trace elements in a suspension of Haloferax volcanii H119 in concentrated and diluted nitric acid were quantified by TXRF and successfully validated by solid-sampling high-resolution continuum source graphite furnace atomic absorption spectrometry (SS-HR-CS-GFAAS). Second, conventionally prepared sample carriers were compared with sample carriers prepared using a nanoliter dispenser (M2 Automation, Berlin, Germany). For this purpose, low nanoliters of prepared suspensions were applied in a grid pattern and the resulting analytical figures were compared to sample carriers with a manually pipetted spot of the same total volume. In addition, the greenness of the analytical procedure and sample preparation method was was evaluated using the Analytical Greenness Calculator (AGREE) and the Analytical Greenness Metric for sample preparation (AGREEprep). The greenness evaluation showed a better result for TXRF measurement compared to GFAAS and a better AGREEprep score for suspension in diluted acid compared to concentrated nitric acid.

Light-driven catalytic systems and their molecular components, specifically the photosensitizer and the catalyst, are known to suffer from degradation due to irradiation or harsh reaction conditions. The underlying mechanisms and kinetics are not yet well understood and investigation attempts often rely on invasive, destructive, and ex situ analysis techniques. Previous studies have shown that using in situ multi-spectroscopic analytical platforms with IR-ATR and Raman integration can enable online monitoring of reaction and degradation products with high temporal resolution. However, reaction engineering concepts are not commonly considered during the design of such platforms, which can lead to uncharacterized and unfavorable reaction conditions and consequently, contribute to accelerated system degradation and challenging data comparability. As part of the CataLight CRC/TRR 234 project C2, this work aims to combine reaction engineering and spectroscopic insights to generate high quality reproducible data in order to generate understanding and ensure comparability of different light-driven systems. The focus lies on the development of characterized homogeneous and membrane measurement cells and reactors, optimized for multi-spectroscopic analyses under both batch and flow conditions. Taking functionalized films into consideration, the high temporal resolution is extended by another dimension through additional spatial information via Raman microscopy and µXRF mapping. Generated knowledge on degradation can also give an insight into possible repair and self-regulating mechanisms.

The synthetic cathinone α-pyrrolidinoisohexiophenone (α-PiHP) is among the most frequently detected new psychoactive substances (NPS) in drug seizures across the European Union. Its widespread use and involvement in overdose cases highlight serious public health concerns, yet its metabolic and toxicological profiles remain poorly understood. To address this gap, we employed a multimodal analytical approach integrating live-cell synchrotron radiation Fourier transform infrared spectroscopy (SR-FTIR), Raman spectroscopy, and liquid chromatography–high-resolution tandem mass spectrometry (LC-HRMS/MS) to investigate the metabolic effects of α-PiHP in hepatic cells.

Live HepG2 cells were used for SR-FTIR analysis, fixed HepG2 cells for Raman spectroscopy, and upcyte® human hepatocytes for LC-HRMS/MS profiling of both extracellular media and intracellular content. Vibrational spectroscopy revealed α-PiHP-induced macromolecular alterations in proteins, lipids, and nucleic acids, while LC-HRMS/MS identified perturbations in key metabolic pathways. Multivariate and pathway analyses indicated that α-PiHP shares common metabolic disruptions with other NPS, suggesting potential conserved mechanisms of hepatotoxicity.

This comprehensive strategy enabled a detailed characterization of α-PiHP’s cellular effects, contributing valuable insights for toxicological risk assessment and the development of therapeutic strategies in cases of α-PiHP intoxication.

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Advances in Instrumental Analytical Chemistry are often linked to technological developments in neighboring disciplines. This is the case with respect to recent advances in mid-IR quantum cascade lasers (QCLs) which are increasingly used as light sources in mid-IR spectroscopy. QCLs offer high spectral power densities, fast amplitude and frequency modulation possibilities, polarized and coherent radiation. Based on these properties a range of new sensing schemes can be developed. In photothermal spectroscopy adsorption induced heating takes place leading to physical changes in the sample matrix. For gas sensing we observe small changes of the sample´s refractive index which can be measured and related to the concentration of the target analyte. Most sensitive measurement of refractive index changes can be realized using Fabry Perot interferometers as transducers. In this talk I will introduce ICAPS (interferometric cavity assisted photothermal spectroscopy) and show how sub-ppb concentration levels can be detected by means of a balanced detection approach, and finally how this new gas sensor technology can be miniaturized and possibly integrated on a single chip. With respect to liquid sensing the basic concepts of thermal lens, thermal mirror and thermal beam deflection will be presented and application on the measurement of solutes in organic solvents as well as water presented. Also concerning liquid sensing, I will introduce the efforts under way toward sensor miniaturization, mainly using photonic integrated circuitries, such as micro-ring resonators (MRR) and Mach Zehnder Interferometers (MZI) as transducers to detect absorption induced temperature and hence refractive index changes of the sample.

We present a unified X-ray Emission Spectroscopy (XES) and X-ray Diffraction (XRD) approach for real-time, in situ characterization of materials, demonstrated on Co2FeSi Heusler alloys under varied heat treatments. The combination of XES and XRD is particularly well-suited to Heusler alloys, where subtle changes in atomic ordering and electronic structure (e.g. site occupancy, hybridization, and spin state) are tightly interdependent and critical for their magnetic and transport properties. In addition, this method enables more efficient materials design by reducing experimental iterations through comprehensive structural and electronic analysis. Developed at the mySpot beamline at BESSY-II, the platform integrates (a) digital twin-based experiment planning, (b) open-source XES spectral simulations, (c) an optimized single-shot, two-element XES setup with sub-pixel resolution for enhanced energy precision, and (d) result-driven beamtime utilization. With an unprecedented synchronized XES-XRD platform, we aim to shed light on how diffusion-controlled processes in Heusler alloys and double perovskites at elevated temperatures establish the formation of specific phases with distinct structure types in real time. This, in turn, strongly impacts the functional properties of the materials under scrutiny.

Nanoparticles (NPs) are increasingly recognized for their diverse applications, primarily due to their unique properties at the nanoscale. To effectively analyze these particles, precise characterization is essential, with Single Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS) emerging as a vital technique for nanoparticle analysis [1].

However, traditional SP-ICP-MS methods, which are tailored for analyzing NPs in suspension, encounter issues such as sample stability, inefficiencies in sample introduction, and spectral interferences from the medium. To overcome these challenges, employing laser ablation (LA) as a solid sample analysis technique offers significant advantages for NP characterization [2-4].

Generally, for SP-ICP-MS, the need for fast data acquisition is critical, as NPs generate extremely narrow signal peaks. This means that Quadrupole-ICP-MS typically analyzes only a single element for SP measurements, since it operates sequentially. In contrast, for multi-element nanoparticle analysis, an ICP-TOF-MS is required to simultaneously monitor multiple m/z values during the short signal spikes produced by the nanoparticles.

However, by applying collision/reaction gases, these signal peaks can be effectively widened as demonstrated by Bolea-Fernandez et al [5]. Chun et al. [6] presented a method that applied this peak broadening with reaction gases to facilitate dual-isotope measurements of individual NPs with a quadrupole ICP-MS.

This study combines the peak-broadening approach that facilitates multi-element SP-Q-ICP-MS with LA as the sampling technique. It was applied for the analysis of Gadolinium doped Ceria (GDC) nanoparticles, which are used in electrochemistry for Solid Oxide Fuel Cells. The direct analysis introduces novel benefits to the procedure, and the results aim to contribute to the ongoing evolution of laser ablation SP-ICP-MS methodologies.

[1] D. Mozhayeva and C. Engelhard, J. Anal. At. Spectrom., 2020, 35, 1740–1783.

[2] S. Yamashita, Y. Yoshikuni, H. Obayashi, T. Suzuki, D. Green and T. Hirata, Anal. Chem., 2019, 91, 4544–4551.

[3] D. Metarapi, M. Šala, K. Vogel-Mikuš, V. S. Šelih and J. T. Van Elteren, Anal. Chem., 2019, 91, 6200–6205.

[4] L. Kronlachner, Z. Gajarska, P. Becker, D. Gunther and A. Limbeck, J. Anal. At. Spectrom., 2025, 40, 467–477.

[5] E. Bolea-Fernandez et al., Anal. Chim. Acta, 2019, 1077, 95–106.

[6] K. H. Chun, J. T. S. Lum and K. S. Y. Leung, Anal. Chim. Acta, 2022, 1192, 339389.

The increasing demand for sustainable waste management in post-disaster scenarios highlights the urgent need for innovative and efficient recovery strategies. A key challenge in C&DW recycling is the heterogeneous and potentially hazardous nature of the materials. To address this challenge, cutting-edge Hyperspectral Imaging (HSI) combined with chemometric modeling has been investigated and implemented as a powerful, non-destructive, and high-throughput approach for the classification of debris components. HSI captures detailed spectral signatures across the visible (VIS) and near-infrared (NIR) ranges, enabling the precise identification and differentiation of materials such as concrete, mortar, bricks, tiles, ceramics, and other constituents commonly found in construction and demolition waste. The use of Partial Least Squares - Discriminant Analysis (PLS-DA) further enhances the system’s ability to distinguish between recyclable and non-recyclable fractions, paving the way for automated waste sorting.

Beyond optimizing waste recovery efficiency, this approach unlocks new opportunities for repurposing fine-grained C&DW fractions, which are traditionally discarded. By transforming these materials into valuable resources for eco-friendly construction products and environmental remediation, the study promotes a circular economy paradigm in the construction sector. The adoption of HSI-based classification systems can revolutionize material recovery processes, reducing landfill dependency and fostering a more resilient and sustainable approach to post-disaster waste management.

The study was developed in the framework of the RUB2RES (Rubble-to-Resource: Earth science knowledge for sorting and recycling Construction and Demolition Waste) [https://bscndr.wixsite.com/my-site-2] project - PRIN (Progetti di Rilevante Interesse Nazionale) 2022. The project aims to develop advanced methodologies for the classification and recovery of Construction and Demolition Waste (C&DW), mainly focusing on post-earthquake debris from Marche, Abruzzo, and Emilia-Romagna. Following the 2016–2017 earthquakes in Central Italy, an estimated 2.7 million tons of rubble were generated, emphasizing the necessity of a systematic and scalable approach to waste valorization.

Laser-induced breakdown spectroscopy (LIBS) has proven to be a powerful technique for in-situ elemental analysis across a wide range of applications. In recent years, there has been growing interest in extending this technique to extreme environments, where conventional analytical methods are impractical or impossible. One particularly challenging yet promising domain is underwater LIBS, which enables direct, non-destructive chemical sensing in complex maritime environments.

However, deploying LIBS underwater is technically demanding. High hydrostatic pressure, optical signal attenuation in water, turbulence and limited accessibility to measurement targets require robust system designs and adapted measurement strategies. The creation and detection of laser-induced plasma underwater differs fundamentally from atmospheric conditions, necessitating specific modifications to laser parameters and optical configurations.

This presentation highlights recent advances in underwater LIBS, drawing from a combination of fundamental research, field-tested systems, and applied projects. Among these are two research initiatives - LIBS60 and ROBUST - in which newly developed and deployed compact LIBS systems for submerged operation at depths of up to 6000 meters were used. The motivation was to analyze mineral resources, map the seabed and identify rare earth elements. LIBS60 contributed to a fundamental understanding of LIBS in deep-water environments, while laboratory testing and ROV-based field trials in ROBUST explored the practical implementation of the technology under realistic ocean conditions.

Additionally, the talk presents insights from the ongoing EU project NERITES, in which LIBS plays a central role as an integrated sensor system for long-term monitoring of material degradation in underwater cultural heritage environments. The project exemplifies the strategic importance of LIBS as part of a broader framework of autonomous, multi-sensor platforms designed for environmental intelligence in ocean technology.

By combining technical developments with real-world applications, the presentation provides a comprehensive overview of how LIBS is progressing toward reliable, autonomous operation in some of the most demanding environments. It also reflects on the growing importance of underwater LIBS in both scientific and industrial contexts - from deep-sea exploration and offshore energy systems to coastal environmental surveillance.

Deoxyribonucleic acid (DNA) is the carrier of genetic information for all living organisms. Even a small mutation in DNA sentence can cause many diseases. Therefore, an early and accurate diagnosis of a specific DNA mutations has a decisive role for effective treatment. Especially, when an immediate decision on treatment most needs to be made, the rapid and precise confirmation of clinical findings is vital.

BRCA1 and BRCA2 are multifunctional proteins that play an important role in maintaining the integrity of the genome, as they are involved in DNA damage repair processes by homologous recombination. Disruption of their function, due to genetic pathogenic variants in the BRCA1 and BRCA2 genes, results in increased sensitivity of cells to DNA-damaging agents. To date, more than 20,000 sequence variants have been described in BRCA1 and BRCA2 genes, with the majority being deletions or insertions leading to a change in the reading frame, and substitutions resulting in premature translation termination and the formation of a truncated protein product. Carriers of mutations in the BRCA1 gene are more likely to develop aggressive triple-negative breast cancer, and in the case of developing cancer hormone-dependent, HER2-negative cancers are more likely to be diagnosed with lower estrogen receptor levels, higher histologic grade, and higher Ki67 proliferation index than women without the mutation. Therefore, we decided to construct and test using clinical samples SERS (surface-enhanced Raman scattering) and SPR (surface plasmon resonance) sensors for the identification of some variants of BRCA1 gene mutations (5370C>T, 300T>G, 5382insC, 4154delA, 185delAG, 1799T>A, and 3819delGTAAA).

We found that, when one immobilizes ‘thiolated’ (with an attached alkanethiol moiety) capture single-stranded DNA (ssDNA) and 6-mercaptohexan-1-ol on a gold (or silver) surface, and the structure formed is incubated with a sample containing DNA complementary to the immobilized capture ssDNA, the presence of the target ssDNA induces hybridization, which causes a change in the conformation of the chains of chemisorbed ω-substituted alkanetiols (6-mercaptohexan-1-ol and the alkanethiol linking moiety via which the captured single-stranded DNA is attached to the gold surface). That change is indicated by a characteristic change in the measured SERS spectrum: the intensities of the ν(C–S) bands of the trans and gauche conformer of the Au–S–C–C chain (alkane chains of both: chemisorbed 6-mercaptohexan-1-ol and the alkanethiol linking moiety via which the captured single-stranded DNA is attached to the gold surface) and the intensity of the band due to the breathing vibration of adenine. For example, such DNA SERS sensor for detection of 1799T>A mutation in BRCA1 is characterized by the low detection limit at the level of pg μL^–1 and a wide analytical range from ca. 7 pg μL^–1 to 70 ng μL^–1. Selective hybridization of target DNA with the capture DNA immobilized strongly influence SPR response, and therefore, gene mutation identification was also realised using SPR signals. It is worth emphasizing that in both types of sensors (SERS over SPR) the same capture DNA was used.

We found that for different DNA sequences, a SPR or SERS sensor achieves greater detection sensitivity, which means that the selection of the optimal sensor type depends on the sequence of the target DNA. The proposed analytical approaches demonstrated completely new capabilities of SPR and SERS techniques and new insights into gene mutation detection.

Acknowledgments: This work was financed by the National Science Centre, Poland, project No. 2019/35/B/ST4/02752.

Interactions between prokaryotic and eukaryotic microorganisms have been shown to be essential for the proper functioning of ecosystems. For instance, Streptomyces species produce polyketides derived from arginine—referred to as arginoketides—that serve as key mediators in cross-kingdom interactions with Aspergillus fungi, ultimately triggering the synthesis of natural products. These arginoketides, which can be cyclic (e.g., monazomycin and desertomycin A) or linear (e.g., lydicamycin and linearmycin A), are produced by Streptomyces iranensis and have been observed to stimulate the orsellinic acid gene cluster in Aspergillus nidulans [1].

To investigate these phenomena, surface-enhanced Raman spectroscopy (SERS) is employed to elucidate the release of those products in the environment and how they provoke responses in other microorganisms [2]. For this purpose, a specialized silver substrate was fabricated on a silicon wafer through the galvanic replacement of silver and sulfate ions, resulting in a dendritic structure. On the nanoscale, the branching of this tree-like network creates sharp angles and narrow gaps that act as “hot spots”, thereby enhancing the Raman signal of the target molecules. The Raman and SERS spectra of compounds produced by both S. iranensis and A. nidulans exhibit distinct marker modes, which facilitate their detection and identification within microbial cultures.

Acknowledgment: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) ‎under Germany´s Excellence Strategy – EXC 2051 – Project-ID 390713860.‎

[1] M.K. Krespach et al. (2023). Nature Microbiology, 8, 1348–1361.

[2] D. Cialla-May et al. (2022). Analytical Chemistry, 94, 86-119.

Vibrational spectroscopy has recently promisingly emerged as a potential tool for pathogens detection and structural investigation [1-5]. Infrared (IR) and the more innovative Terahertz (THz) spectroscopy are widely used for studying biomacromolecules [1,2,5,6], and for characterization of viruses [2,7]. IR spectroscopy offers several advantages over gold standards (such as ELISA, RT-PCR, bDNA). It does not require chemical pre-treatment of the sample, measurements are rapid, low-cost and unique for all viral samples. Employing a functionalized sensor platform coupled to spectroscopy it would be possible to perform large scale measurements in an open environment, not simply focusing on the extracted sample as common biochemical assays do.

Coupling the unique structural information provided by vibrational spectra with a sensor platform specifically optimized for airborne pathogens adsorption, would enable the development of a label-free, real-time ultrasensitive optical biosensor. For instance, silicon and/or metal oxides substrates are suitable to be nanostructured and engineered, and their surfaces can be modified with a dedicated bioconjugation based on different approaches. These procedures would allow to increase the selectivity and to obtain an optimized sensor capable of concentrating viral capsids, which can then be inspected with IR spectroscopy.

As a preliminary and essential step for achieving the design of a biosensor based on vibrational spectroscopy, in this work we report the IR spectroscopic characterization of viral proteins from different species of coronaviruses, considered as bioanalytes of interest. Specifically, Spike protein has been considered as biomarker, measured and investigated via Attenuated Total Reflection-IR (ATR-IR) spectroscopy.

Deeply focusing on the inspection of proteins amide I band (1600-1710 cm^-1) and its deconvolution [1,6], on one hand we proved the potential of IR spectroscopy to uniquely characterize a specific viral species; moreover, we provided a structural investigation of the protein under different external conditions, in terms of secondary structure, conformational order and hydrophilicity.

Here, we present an overview of our results obtained from a systematic and comparative study of coronaviruses viral proteins, SARS-CoV-2 individual protein domains, namely the Receptor Binding Domain (RBD), subunit 1 (S1) and 2 (S2) regions, and Spike (S) protein, as well as SARS-CoV-2 S1 variants at serological pH, by measuring the amide I absorption band (1600-1700 cm-1) using Attenuated Total Reflection Infrared (ATR-IR) spectroscopy [5-7]. Firstly, three cases of study are shown, starting from the IR characterization of SARS-CoV-2 S protein and its domains, from the RBD, through S1 and S2, up to the whole S protein. Secondary structure contents of different domains have been estimated, and results are compared with MultiFOLD+DSSP computational approach; in addition, the contribution of each domain to the hydrophilic/hydrophobic profile and to the conformational order of the whole S protein has been evaluated from amide I bands shapes and computational tools [6].

After this characterization, in a first comparative study, the IR spectral analysis of S1 proteins from MERS-CoV, SARS-CoV and SARS-CoV-2 viruses reveals notable differences in their amide I bands, related to notable differences among their structures and in the intermolecular b-sheet content. Moreover, pH dynamic of SARS-CoV-2 S1 protein sheds light on remarkable conformational changes and adaptation of S1 proteins occurring during the infectious process [1].

Finally, another case of study focused on the comparative study of Alpha, Gamma and Omicron variants of SARS-CoV-2 virus, differing for a very small number of mutations with respect to wild type species. Through Circular Dichroism (CD) and IR spectroscopy and Molecular Dynamics (MD) simulations, a comprehensive experimental and computational structural analysis is reported, revealing remarkable spectral differences and relating them to proteins conformational behaviour and functionality.

References:

[1] D’Arco, A. et al. Secondary Structures of MERS-CoV, SARS-CoV, and SARS-CoV-2 Spike Proteins Revealed by Infrared Vibrational Spectroscopy. Int. J. Mol. Sci., 24, 2023

[2] Piccirilli, F. et al. Infrared Nanospectroscopy reveals DNA structural modifications upon immobilization onto clay nanotubes. Nanomaterials, 11(5):1103, 2021

[3] Quintelas C. et al. Biotechnol. J., 13, 1700449, 2017

[4] Mancini T. et al. New Frontier in Terahertz Technologies for Virus Sensing. Electron-ics, 12(1), 135, 2023

[5] Barth A. and Zscherp C. What vibrations tell about proteins. Q. Rev. Biophys. 35(4), 369, 2022

[6] Mancini T. et al. Infrared Spectroscopy of SARS-CoV-2 Viral Protein: from Receptor Binding Domain to Spike Protein. Advanced Science 11.39, 2400823, 2024.

[7] Fardelli, E. et al. Spectro-chim. Acta A Mol. Biomol. Spectrosc., 288, 122148. 2023

Microbial preparations have a long history of applications in broad and diverse areas of biotechnology, including medical and food biotechnologies; as active plant-growth-promoting components of biofertilisers in agrobiotechnology; in bioremediation (and phytoremediation) of contaminated soils and water, etc., many of which are currently in rapid development. A crucial issue for such preparations is their shelf life and long-term preservation (mainly in frozen or dry states). To control their safety and to optimise storage conditions, molecular-level analyses of the cell biomass and monitoring its composition in situ or in vivo is of primary importance. Over the last decade, along with microbiological, biochemical and molecular biological approaches, modern molecular spectroscopy techniques have been increasingly applied in this challenging area of bioanalysis.

In a series of our recent studies using in-situ transmission ⁵⁷Fe Mössbauer spectroscopy (see, e.g. [1, 2] and references therein), it was noticed that, while assimilating iron(III) from the medium by its reduction to iron(II) with a notable Fe^II accumulation (which is typical of many microorganisms [2]), two Azospirillum species (widely studied phytostimulating rhizobacteria) showed a dramatic decrease in the relative content of iron(II) in dry biomass obtained by lyophilisation [1]. Note that this method (freeze-drying under vacuum) is widely used in biotechnology to obtain dry microbial preparations for long storage, in which the cells remain alive (in the dormant state, with very low metabolic rates). It is essential that active cells can metabolically control the formation of cell-damaging reactive oxygen species (ROS) as a result of Fenton-type reactions (FTRs) involving cellular Fe^II, whereas in dry (dormant) cells such a comprehensive metabolic control is impossible. Hence, it was suggested [1] that the possibility for a spontaneous oxidation of assimilated cellular Fe^II to Fe^III upon lyophilisation could be a natural strategy to avoid cell damage owing to FTRs. In our further ⁵⁷Fe Mössbauer spectroscopic studies ([3] and papers in preparation), this hypothesis has been confirmed on three other bacteria (another Azospirillum species, Enterobacter cloacae and Bacillus sp., which are all used in agriculture). Thus, all of them accumulated significant amounts of ⁵⁷Fe(II) from the medium (over 20% of the total ⁵⁷Fe cellular pool), while in their lyophilised samples, either no or only a minor part of ⁵⁷Fe^II was detected. Low-temperature Mössbauer spectroscopic measurements (at T ≈ 5 K) allowed various states of cellular ⁵⁷Fe(III) species to be distinguished.

In these experiments, it was of importance to control the state of cellular biomass in the fresh and lyophilised states. This was realised using FT-Raman spectroscopy (with the 1064-nm excitation wavelength to avoid fluorescent noise), which showed that, for each bacterium, all the main vibrational bands typical of cellular constituents were similar in both fresh (wet) biomass and lyophilised samples obtained thereof. FTIR spectroscopy, widely applied in microbiology [4], was also used to compare vibrational spectra of the lyophilised bacterial samples [5].

A combination of molecular spectroscopic techniques can thus provide a realistic picture of biotechnologically relevant processes occurring in live microbial cells upon drying. Note that desiccation is also one of natural states of soil microorganisms, in which they can survive. Transmission ⁵⁷Fe Mössbauer spectroscopy is a unique probe for in-situ cellular iron speciation and redox transformations [1–3], and vibrational spectroscopic techniques are modern instrumental tools highly sensitive to the composition and fine structural features of macromolecular cellular constituents [4–6].

Funding. This work has been supported by the Russian Science Foundation (grant no. 24-26-00209).

References

[1] A.A. Kamnev, A.V. Tugarova, A.G. Shchelochkov, K. Kovács, E. Kuzmann. Spectrochim. Acta Part A, 229 (2020) 117970.

[2] A.A. Kamnev, A.V. Tugarova. Russ. Chem. Rev., 90 (2021) 1415–1453.

[3] A.A. Kamnev, K.V. Frolov, S.S. Starchikov, Yu.A. Dyatlova, S.A. Klimin, I.S. Lyubutin, A.V. Tugarova. In: A.A. Kamnev (Ed.), Plants and Microorganisms: Biotechnology of the Future. Cambridge Scholars Publ., Newcastle upon Tyne, U.K., 2025 (in press).

[4] A.A. Kamnev, A.V. Tugarova. J. Analyt. Chem., 78 (2023) 1320–1332.

[5] O.A. Kenzhegulov, Yu.A. Dyatlova, S.A. Klimin, A.V. Tugarova, A.A. Kamnev. Microbiology, 93 (2024) S153–S156.

[6] A.V. Tugarova, A.A. Vladimirova, Yu.A. Dyatlova, A.A. Kamnev. Spectrochim. Acta Part A, 329 (2025) 125463.

Widefield O-PTIR is a novel multi-modal technique for super-resolution infrared chemical imaging and spectroscopy, enabling sub-500 nm spatial resolution, rapid widefield IR absorption imaging in seconds or less, and full hyperspectral image acquisition in minutes. It is a new chemical imaging mode built upon the optical photothermal infrared (O-PTIR) platform, which employs fluorescence-detected photothermal IR (FL-PTIR). FL-PTIR achieves its speed and resolution advantages by detecting changes in fluorescence emission induced by IR absorption, applicable to both fluorescently labeled samples and autofluorescent biological materials. FL-PTIR offers a spatial resolution by a factor of 10-30X better than conventional IR spectroscopy, utilizing a visible probe beam to monitor IR-induced thermal changes on length scales below the classical diffraction limit.

In FL-PTIR, a tunable pulsed IR laser selectively excites molecular vibrations, inducing localized heating where absorption occurs. This thermal effect decreases fluorescence emission efficiency in fluorescent regions of the sample due to reduced quantum yield. The changes in fluorescent emission are detected using an s-CMOS camera across a widefield area. Sequential acquisition at multiple IR wavelengths yields hyperspectral image stacks that can be processed to extract detailed IR absorption spectra from specific regions of interest, revealing the spatial distribution of chemical species. The high temperature dependence of fluorescence quantum yield (~1%/°C) offers ~100X greater sensitivity compared to the intrinsic photothermal sensitivity of most materials, significantly reducing integration times. Additionally, the simultaneously acquired fluorescence images provide specific molecular targeting for chemical analysis.

We present FL-PTIR chemical images and spectra of fluorescently labeled cells, brain tissue, and bacteria, as well as of autofluorescent samples such as collagen, diatoms, microalgae, and plant tissue – including measurements of living specimens in water. Spectra extracted from FL-PTIR hyperspectral datasets demonstrate sensitivity to subtle chemical heterogeneity within biological samples.

FL-PTIR represents a promising approach for rapid, super-resolution infrared chemical imaging of fluorescently labeled and autofluorescent biological materials. By exploiting the strong thermal dependence of fluorescence quantum yield, it enables detailed chemical characterization with submicron spatial resolution, offering new opportunities for dynamic and label-guided vibrational imaging in complex biological systems.

Preconcentration is a key enabling step in trace gas analysis, particularly when using mid-infrared (MIR) spectroscopy to detect volatile organic compounds (VOCs) in the low ppm range. Although MIR techniques provide inherent molecular selectivity, their sensitivity at such concentrations is often insufficient for reliable detection in miniaturized or field-deployable systems. Here, we present a modular sensing platform that combines thermally regulated multichannel preconcentration (muc-IPRECON) with substrate-integrated hollow waveguides (iHWGs) for enhanced MIR detection performance.

The muc-IPRECON module incorporates up to three independently addressable sorbent channels within a compact aluminum substrate, enabling thermoelectrically controlled low-temperature adsorption (e.g., at −10 °C) and subsequent thermal desorption. A Peltier element ensures active cooling while maintaining a compact and portable design footprint. This configuration allows for flexible and selective enrichment of target VOCs under dynamic sampling conditions. Enriched analytes are guided into an iHWG gas cell, which is coupled to a FTIR spectrometer for real-time MIR analysis. The system accommodates various sorbent materials and is adaptable to a wide range of analytes and application scenarios.

System performance was demonstrated using a variety of VOCs spanning different target molecules and concentration ranges relevant in medical, environmental, and industrial contexts. Examples include acetone (as a biomarker in breath) and methane (as an industrial and environmental contaminant). By combining optimized sorbent materials with controlled low-temperature adsorption and thermal desorption, enrichment factors of up to 150 were achieved, enabling significantly improved limits of detection and quantification compared to direct MIR analysis. Full enrichment and measurement cycles were completed within minutes, supporting rapid, selective, and repeatable trace gas monitoring under real-world conditions.

This approach demonstrates how modular thermal preconcentration, combined with compact MIR photonic components, enables highly sensitive and selective VOC detection in practical, field-relevant applications.

Ref:

Kokoric V. et al., “IPRECON: An integrated preconcentrator for the enrichment of volatile organics in exhaled breath”, doi:10.1039/C5AY00627K

Kokoric V. et al., “muciPRECON: Multichannel preconcentrators for portable mid-infrared hydrocarbon gas sensors”, doi:10.1039/C6AY01236H

Barreto D. N. et al., “From light pipes to substrate-integrated hollow waveguides for gas sensing: A review”, doi:10.1021/acsmeasuresciau.1c00007

Barreto D. N. et al., “Mid-infrared acetone gas sensors using substrate-integrated hollow waveguides augmented by advanced preconcentrators”, doi:pending

Chemical analysis plays a vital role in numerous fields, where spectroscopic techniques serve as essential tools. However, the complexity of samples often necessitates the combination of multiple spectroscopic methods to achieve accurate and reliable results. Multispectral measurements offer a synergistic effect, especially for rapidly changing or heterogeneous media in chemical and biochemical reactions. Fiber optics helps to integrate different spectroscopic techniques within a single probe, providing simultaneous analysis of media composition at the same point and time.

A strong advantage of fiber optic spectroscopy is in its capability to enable chemical reaction monitoring or process-control in-line in various applications, including harsh environments, such as wide temperature ranges from -150°C to +250°C, high pressure up to 200 Bar or in vacuum, and where there are vibrations, aggressive liquids or gases, or electromagnetic fields, including microwave and hard radiation. This advantage permits remote process-control even in industry – in contrast with laboratory conditions – and this feature is highly requested to secure sustainable process control. Depending on the chemical process or materials to be analyzed, fiber probes can be based on 4 different fiber types selected for the required spectral range and used for Transmission, Reflection, ATR-absorption, Raman & Fluorescence spectroscopies. Advanced fiber optic combi probes can utilize two spectroscopic methods in the same probe shaft - such as Mid-FTIR+Fluorescence, Raman+Near-IR, Raman+Mid-FTIR and even combinations of three techniques as well. Spectral data fusion from complementary methods enables enhanced sensitivity and accuracy of the media composition analysis for automated process control in-line.

Here we present our latest development of a multispectral fiber probe capable of obtaining Raman spectra alongside attenuated total reflection (ATR) for Mid IR-absorption, and fluorescence spectroscopy. Raman scattering and fluorescence emission, despite their different physical nature, are often observed together, and their spectral signals can overlap. Example applications of this triple method combi-probe will be presented – to distinguish the cheapest rapeseed and a high-grade extra virgin olive oil. Wide variability of the chemical composition of the natural products due to the different growing conditions makes olive oil samples difficult specimens. Application of an appropriate mathematical processing to complementary spectral data fusion illustrates the advantage of having three different spectroscopy methods used with one combi-probe. Depending on the sample nature and the analytical problem being solved, various pairwise combinations of methods, and in some cases their triple combination, can result in a synergistic improvement.

Another interesting combi-probe application of the fusion of ATR-absorption and Fluorescence spectra will demo how to differentiate 3 types of chicken tissues when only 2 information rich wavelengths in the Mid IR and Visible ranges were selected. This allowed design of a simple low-cost spectral fiber sensor to replace expensive FTIR and Fluorescence spectrometers for this distinct application. The concept opens the way to develop a broad range of cost-effective IoT Spectral Fiber Sensors for customized process control and sustainable automation in food, biotech, chemical, pharma and other industries.

The latest development was made for Combi-probe which enable to collect Raman and Mid InfraRed absorption spectra from the same spot – combining all specific bands for molecular vibrations. Example of its application will be presented for 2 combinations of spectrometers Raman with FTIR-spectrometer and Raman with NLIR-spectrometer - super fast Non-Linear InfraRed spectrometer from Company NLIR, Denmark.

The role and toxicity of trace metals in both environmental and biological systems are critically dependent not only on their total concentration, but on the specific chemical (species) and physicochemical (nanoparticles) forms, in which they occur.

Historically, atomic spectroscopic techniques, such as atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), and, lateron, ICP mass spectrometry (ICP-MS), were used primarily, if not uniquely, for bulk elemental analysis. Their coupling with chromatographic or electrophoretic separations, so-called "hyphenated techniques", enabled the resolution of individual metal-containing species with sub-picogram sensitivity. These advances underpinned much of the progress in environmental and bioinorganic trace element speciation analysis, particularly in quantifying individual metal pollutants, explaining the metabolism of metal probes, and tracing the metal circulation routes in the environment. The emergence of single particle ICP-MS allowing the determination of particle size (based on signal intensity) and particle number concentration (based on spike frequency) made possible the analysis of insoluble metal species, thus extending the scope of speciation analysis beyond the molecular properties.

However, the atomic spectroscopic approaches often fall short when faced with the complexity and diversity of naturally occurring metal species, especially in biological systems and omics-level studies. The emergence of electrospray ionization and high-resolution accurate-mass (HRAM) mass spectrometry, including Fourier-transform ion cyclotron resonance (FT-ICR) and Orbitrap platforms, opened new avenues for the detection and identification of intact metal-containing molecules with resolutions by far exceeding those offered by chromatography or electrophoresis. By recognizing isotope patterns and using accurate mass profiling, HRAM-MS facilitates the direct molecular-level identification of metal complexes within complex biological or environmental matrices. It enables the mapping of dozens of trace metal species simultaneously across biological tissues, environmental compartments, or food chains—capturing a more realistic and functional picture of metal distribution and activity.

The lecture will discuss the evolution of atomic and plasma spectrometry to become essential complements to molecular mass spectrometry, providing critical isotopic, quantitative, and structural information. It will highlight the convergence of atomic spectrometric traditions with molecular innovations, illustrating how trace element analysis is being transformed by hybrid approaches. Recent examples of multimethod characterization of environmental and biological systems will be showcased, combining chemical and physico-chemical speciation analysis.

In this work, a pyrohydrolysis method was proposed as a sample preparation procedure and further determination of halogens in commercial drugs used for treatment of hypertension and depression. Inductively coupled plasma mass spectrometry (ICP-MS) was used for for Br and I determination, ion chromatography (IC) for F and Cl determination, and potentiometry with ion-selective electrode (ISE) for F determination. The influence of the following parameters involved in the pyrohydrolysis reaction were evaluated: temperature, reaction time, sample mass, absorbing solution, carrier gas flow rate, water flow rate, and need for the use of auxiliary reagents. It was observed that, under the experimental conditions employed, better RSDs (< 10%) were obtained by using of 1000 °C of temperature for 10 min of reaction and with a carrier gas flow rate of 0.2 L min^-1. Relatively high sample mass (500 mg) was used and for some cases sample was mixed with 500 mg of SiO₂, and insertion speed of boat into the reactor of 0.03 cm s^-1. The results were compared with those obtained by the reference method using microwave-initiated combustion (MIC) and the obtained results did not differ significantly (t-test, with a confidence level of 95%). Accuracy was evaluated using certified reference materials and by using standard addition recovery assays in three levels (50, 100, and 150%). The results obtained were in agreement with the reference values and with the addition of analyte in more than 90%. The quantification limits obtained were better than 15 μg g⁻¹ for F and Cl by IC, better than 0.036 μg g⁻¹ for Br and I, respectively by ICP-MS, and 3.0 µg g^-1 for F by ISE. The proposed pyrohydrolysis method proved to be suitable for the determination of halogens in drugs with minimal use of reagents and waste generation and providing digests completely compatible with multitechnique determination (ICP-MS, IC and ISE).

Advances in instrument technologies in the recent decade have led to significant improvements in the time resolution for Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). On the one hand, rapid response cells were developed allowing for the fast washout and therefore detection of the material generated during laser ablation. On the other hand, the time resolution of the mass spectrometers improved greatly, owing partly to the establishment of Time-of-Flight detectors for coupling with LA, but also to the reduction in settling time for newer generation quadrupole-based systems. This enabled the investigation of the signal response of individual laser shots, the so-called Single Pulse Response (SPR), which offers new possibilities for spatially resolved analyses.

However, investigations of the SPR of gelatine carried out by van Helden et al.^{1, 2} revealed that some elements (e.g., C, Zn, and Hg) exhibit a bimodal SPR profile, which they attributed to a separation of the ablated material into a particulate and a gaseous phase. This separation was already reported earlier^{3, 4}, but especially when using the SPR concept it can have negative effects on image quality² and may limit the applicability of internal standards.⁴ The latter is particularly significant, seeing that carbon is often used as an internal standard in bioimaging, but also seems a intuitive choice for, e.g., synthetic polymers.

In this contribution, we investigate the two-phase sample transport resulting from the ablation of different synthetic polymers, namely polyimide (PI), poly(methyl methacrylate) (PMMA), polyvinylpyrrolidone (PVP), polysulfone (PSU), and polyvinyl chloride (PVC). The main focus is the SPR profile of carbon, but the signals of sulfur (for PSU) and chloride (for PVC) are discussed too. Parameters influencing the SPR profile (laser energy, spot size, ablation cell parameters) are examined and their impact on the sensitivity for trace analytes is analyzed.

Based on these findings, we discuss the consequences of the two-phase sample transport for different matrices and how this places preconditions on the samples and experimental setup, in order to ensure proper quantification for analytes. In the future, we are aiming to utilize the found relationships between laser parameters, polymer type, etc., to analyze real-life samples containing different polymers, enabling the spatially resolved, matrix-matched quantification of trace elements in the corresponding sample regions.

(1) Van Helden, T.; Mervič, K.; Nemet, I.; van Elteren, J. T.; Vanhaecke, F.; Rončević, S.; Šala, M.; Van Acker, T. Evaluation of two-phase sample transport upon ablation of gelatin as a proxy for soft biological matrices using nanosecond laser ablation – inductively coupled plasma – mass spectrometry. Analytica Chimica Acta 2024, 1287, 342089. DOI: https://doi.org/10.1016/j.aca.2023.342089.

(2) van Elteren, J. T.; Van Helden, T.; Metarapi, D.; Van Acker, T.; Mervič, K.; Šala, M.; Vanhaecke, F. Predicting image quality degradation as a result of two-phase sample transport in LA-ICP-TOFMS mapping of carbon-based materials. Journal of Analytical Atomic Spectrometry 2025, 40 (2), 520-528. DOI: https://doi.org/10.1039/D4JA00288A.

(3) Todolı́, J. L.; Mermet, J. M. Study of polymer ablation products obtained by ultraviolet laser ablation — inductively coupled plasma atomic emission spectrometry. Spectrochimica Acta Part B: Atomic Spectroscopy 1998, 53 (12), 1645-1656. DOI: https://doi.org/10.1016/S0584-8547(98)00219-5.

(4) Frick, D. A.; Günther, D. Fundamental studies on the ablation behaviour of carbon in LA-ICP-MS with respect to the suitability as internal standard. Journal of Analytical Atomic Spectrometry 2012, 27 (8), 1294. DOI: https://doi.org/10.1039/c2ja30072a.

Laser-Induced Breakdown Spectroscopy (LIBS) is recognised as a powerful analytical tool that can provide multi-elemental information from a single laser pulse, requiring minimal sample preparation. LIBS is based on the spectroscopic analysis of a laser-induced plasma, whose spectral signature reveals the elemental composition of the sample. Furthermore, μLIBS imaging, i.e. LIBS analysis with a crater size of less than 20 µm, offers spatially resolved elemental analysis and has applications in diverse fields such as industry, geology, forensics, and biomedicine [1] .

Currently, most μLIBS imaging setups use lasers with a shooting rate of less than 100 Hz. However, the use of kHz lasers could represent a significant breakthrough for elemental imaging analysis [2]. Although the literature presents several examples of the use of kHz lasers in LIBS, mainly focusing on industrial or geological applications, this is not yet widespread. Despite their potential, implementing such lasers in μLIBS imaging would present various challenges, primarily relating to weak plasma emission and signal-to-noise ratio (SNR) degradation, particularly when applied to delicate biological samples.

As the complexity and size of spectral data increase the development of workflows for spectral processing to handle, analyze, and extract analytical information from these data becomes of capital importance. Using kHz lasers allows mapping of 10 million spectra in less than three hours. Therefore, the main limitation lies in processing these large data sets. In this context, we highlight the application of kHz-μLIBS-imaging for the analysis of samples of bioclinical interest, with a focus on a comparative evaluation of 5 different denoising methods. Furthermore, to our knowledge, this research applies principal component analysis (PCA) and Whittaker Smoothing to LIBS data for the first time, opening new ways to improve the accuracy of such analyses [3].

[1] Gardette V. et al, Anal. Chem., 95 (2023), 49-69

[2] Alvarez-Llamas C., et al, J. Anal. At. Spectrom, 39 (2024), pp. 1077-1086,

[3] Guerrini R. et al, Spectrochim Acta B, 227 (2025) pp 107167

The uncontrolled spread of infectious diseases has accelerated the development of advanced materials and bioactive surfaces designed to limit microbial transmission. In the aftermath of the Covid-19 pandemic, significant efforts have been devoted to the creation of antimicrobial materials, with metal-based nanocomposites emerging as some of the most promising candidates for surface coatings. These coatings are now pivotal in sectors such as healthcare, food packaging, and furniture, where broad-spectrum pathogen control is essential.

While the antimicrobial potential of inorganic nanomaterials is well recognized, their exact mechanisms of action remain only partially understood, often involving multiple simultaneous pathways. Establishing a clear correlation between surface properties and bioactivity is therefore crucial for the development of safer, eco-friendly materials with tunable and controllable efficacy.

Our research focuses on achieving antimicrobial functionality through the controlled release of metallic ions from particles embedded in polymeric matrices. Despite the widespread use of such bioactive surfaces, understanding their precise mode of action remains a key challenge, particularly due to the coexistence of different antimicrobial mechanisms. A detailed analysis of surface characteristics and their relation to bioactivity is thus essential, not only for enhancing material safety and sustainability, but also for minimizing antimicrobial resistance through precise dose-response control.

To address this, we investigated the early-stage interaction between inorganic antimicrobial agents and Bacillus subtilis, concentrating on ZnO-based bioactive surfaces. Short-term bacterial motility on these surfaces was examined using laser scanning confocal microscopy (LSCM), coupled with a novel statistical method designed to distinguish between bacteriostatic and bactericidal effects. By employing single-cell tracking, we analysed the trajectories of hundreds to thousands of fluorescently labelled bacteria and calculated the corresponding mean squared displacements (MSD). Additionally, bacterial motility was correlated with the release profile of Zn²⁺ ions from different surfaces.

ZnO nanostructures (NSs) were synthesized via a scalable, aqueous-phase electrochemical method [1]. To modulate morphology, two stabilizing agents - Sodium Dodecyl Sulfate (SDS) and Poly-Diallyl-Dimethyl-Ammonium chloride (PDDA) - were employed. These inorganic antimicrobials were then incorporated into three different polymer matrices (polyethylene oxide, polylactic acid, and poly-vinyl-methyl-ketone) to develop nanocomposite coatings with tunable Zn²⁺ ion release profiles, enabling controlled bioactivity. Comprehensive surface characterization was carried out using UV-Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and both scanning and transmission electron microscopy (SEM/TEM).

To quantitatively assess dose-effect relationships, we monitored bacterial motility following surface contact via particle tracking of LSCM data [2]. MSD analysis revealed a clear transition in motility behaviour: from active run-and-tumble dynamics to constrained, sub-diffusive motion in response to increasing Zn²⁺ concentrations. This suppression of motility aligned with the progression from super-diffusive to sub-diffusive motion, confirming the bacteriostatic impact of ion release. Live/dead imaging further validated the link between Zn²⁺ exposure and bacterial viability.

To our knowledge, few studies have addressed the impact of metal-based antimicrobials on bacterial motility. This integrated analytical approach offers a powerful tool for distinguishing between bacteriostatic and bactericidal effects, supporting the rational design of antimicrobial coatings with spatiotemporally controlled activity.

References:

[1] M. Izzi, M.C. Sportelli, L. Torsi, R.A. Picca, N. Cioffi, Synthesis and Antimicrobial Applications of ZnO Nanostructures: A Review, ACS Appl. Nano Mater. 6 (2023) 10881–10902

[2] G. Bassu, M. Laurati, E. Fratini, Transition from active motion to anomalous diffusion for Bacillus subtilis confined in hydrogel matrices, Colloids and Surfaces B: Biointerfaces 236 (2024) 113797

Luminescent optodes have become essential tools for chemical imaging, allowing for spatially resolved measurements of key analytes such as oxygen and pH. In our laboratory, we have developed a range of advanced imaging strategies that enhance the capabilities of both planar and nanoparticle-based optode sensing, unlocking new applications in environmental and biological research.

This presentation will focus on two main aspects of our recent work. First, we focus on methodological innovations in imaging: from deconvolution-based hyperspectral unmixing for dual-analyte detection, to frame-straddling techniques for time-resolved lifetime imaging using conventional cameras. We also introduce sensPIV, a technique integrating chemical sensing with particle image velocimetry, and grid optodes that enable scalable, multiparameter imaging with pixel-level calibration and modular sensor integration.

Second, we demonstrate how these tools are applied in real-world systems. This includes high-resolution mapping of oxygen and pH dynamics in marine sediments, coral-associated microenvironments, and transparent soil analogs for 3D oxygen imaging. In terrestrial contexts, we present applications in soil systems using the multianalyte real-time in-situ imaging system (MARTINIS), demonstrating how luminescent sensing can support ecosystem monitoring and agricultural research.

A significant focus of our recent work has been on utilizing low-cost, commercially available imaging hardware, including RGB or monochrome cameras equipped with optical filters, to achieve high-performance sensing. We believe this approach lowers technical barriers and promotes the development of accessible tools for end-users in environmental sciences and applied biology. By designing optode-based systems that are modular and compatible with standard instrumentation, we aim to connect technical advancements with practical needs in ecological modeling, water quality monitoring, and soil management.

The presentation is supported by an AIAS-AUFF Fellowship (AK) from the Aarhus Institute of Advanced Studies and Aarhus Universitets Forskningsfond, the Pioneer Center for Research in Sustainable Agricultural Futures (Land-CRAFT), DNRF grant no. P2 (MRR), grants by the Novo Nordisk Foundation (no. 0079370), and by the Grundfos foundation (KK).

Speciomics is a term adapted from the biological sciences [1], referring to the study and evaluation of chemical species within the context of omics approaches. The related term speciome arises from the synergy between chemical speciation and omics, and is defined as the complete set of chemical species analyzed using omics strategies. In simpler terms, speciomics serves as an “umbrella” concept encompassing all omics techniques—such as metabolomics, proteomics, metallomics, and genomics—that are applied to speciation analysis [2].

To illustrate this concept, we present a study involving two distinct biological systems: a biotechnological material (soybean callus), treated or untreated with nanoparticles for preservation, and a marine animal (turtle). From the perspective of speciomics, we aim to identify and characterize molecular species present in these samples, as well as to discover new ones [3].

Through a multimodal analytical platform, we have already identified species containing arsenic (As), calcium (Ca), iron (Fe), magnesium (Mg), zinc (Zn), lipids, and phosphorus-containing metabolites. This was achieved using both positive and negative ionization modes. Notably, novel molecular species have also been discovered. This comprehensive, multimodal approach demonstrates the potential of non-targeted speciomics to provide high-resolution, multi-elemental insight into complex biological systems.

[1] AltTox.org at https://alttox.org/mapp/emerging-technologies/omics-bioinformatics-computational-biology/, Accessed on January, 8^th, 2024.

[2] Arruda, M. A. Z., Jesus, J. R., Blindauer, C. A, Stewart, A. J., J. Proteomics, 12(2020)1878.

[3] Kato, L. S., Silva, V. H. C., Andrade, D. C., Cruz, G., Pedrobom, J. H., Raab, A., Feldmann, J., Arruda, M. A. Z., Anal. Chim. Acta, DOI: 10.1016/j.aca.2024.343084 R.

Gold nanoparticles (AuNPs) are utilized in a wide range of applications including cosmetics, novel medical applications and as food additives. However, there is often a lack of comprehensive knowledge regarding the prevalent particle size distribution, particularly given the potential for changes to occur during processing or storage. The quantification and sizing of AuNPs as well as speciation, with the aim of differentiating between metal ions and nanoparticles, commonly involves the combination or hyphenation of (size) separation techniques, such as field flow fractionation (FFF) with element-specific detection methods, including inductively coupled plasma-mass spectrometry (ICP-MS). However, the identification of very small NPs with diameters in the single digital nm range remains challenging especially in the presence of the ionic metal [1].

Graphite furnace atomic absorption spectrometry (GFAAS) is a technique that enables direct speciation and sizing of metal nanoparticles in liquid as well as solid samples following minimal sample preparation and without the necessity for metal species separation [2]. This approach not only simplifies and speeds up the analysis process but, more importantly, it eliminates or minimizes the risk of unintended alterations in particle size or aggregation. The method is based on the distinction in thermal energy required to atomize metal ions and NPs of different sizes, resulting in a clear correlation between the temporal shift of the transient absorbance signal and the respective size [3].

In the present study, the ability to size AuNPs in the single-digit nm range and to distinguish them from ionic gold in aqueous samples was investigated using the high-resolution continuum source GFAAS (HR-CS-GFAAS). The "time of first inflection point" (t_ip) was introduced as a newly sizing parameter, resulting in a highly reproducible calibration function within the tested working range of 2.2 nm to 10.1 nm. Using t_ip, the size of an unknown particle suspension as determined by high-resolution transmission electron microscopy (HR-TEM) was fully recovered. In addition, a minimum distinguishable size difference of 1.6 nm was experimentally demonstrated, and a theoretical size resolution of 0.3 nm has been predicted. By optimizing the graphite furnace temperature program, we were also able to significantly distinguish particles as small as 2.2 nm from gold ions. Moreover, a detection limit of 0.4 pg, equivalent to 10 ng/L in liquid samples, was achieved for gold quantification.

Acknowledgement:

We thank Chistopher Leist (SALVE Center, UUlm) for TEM and Gregor Neusser (FIB Center, UUlm) for SEM characterization of NPs. Funding was obtained from DFG in project LE 2457/12-1.

Literature:

[1] Blaimer, D. et al., Analytical methods for identification, characterization, and quantification of metal-containing nanoparticles in biological and biomedical samples, food and personal care products, Trends in Anal. Chem. 2024, 181, 118031.

[2] Leopold, K., et al., Sizing gold nanoparticles using graphite furnace atomic absorption spectrometry, J. Anal. At. Spectrom. 2017, 32 (4), 723-730.

[3] Brandt, A., et al., Investigation of the atomization mechanism of gold nanoparticles in graphite furnace atomic absorption spectrometry, Spectrochim. Acta Part B 2018,150, 26–32.

Several analytically important elements such as As, Se, Pb, Sn, Sb, Bi, Te and Ge can be quantitatively converted to their coresponding hydrides. Such a derivatization results in enhanced analyte introduction efficiency and reduced risks of interferences, when compared to liquid nebulization. Hydride generation (HG) can be coupled with atomic absorption (AAS), atomic fluorescence (AFS) or optical emission spectrometry (OES). The most commonly used hydride atomizers in AAS are externally heated quartz tubes (QTA). However, new types of hydride atomizers based on various types of plasma have been used as an alternative in recent years. They are based either on a dielectric barrier discharge (DBD), or atmospheric pressure glow discharge (APGD), the latter one investigated in detail in this work.

APGD is a non-equilibrium plasma sustained between two electrodes powered by a high voltage. The discharge gap reaches typically from 1 to 5 mm and discharge current varies between 10 to100 mA. Plasma gas temperature reaches from 1500 to 3500 K with electron number density of 10¹⁴-10¹⁵ cm^-3. These features indicate the potential of APGD to be used for efficient hydride atomization in HG-AAS. A novel APGD hydride atomizer was constructed in this work with its design derived from a quartz body of a QTA. Instead of resitive heating of the optical arm of the atomizer, two electrodes were inserted into its central part to sustain the APGD discharge (0.5 kV, 30 mA) in the optical axis of the spectrometer.

Atomization conditions have been optimized individually for each element including As, Se, Sn, Sb, Pb, Bi and Te. The effects of discharge gas nature (Ar or He) and its flow rate, the delivered power as well as the role of water vapor and co-generated aerosol on analyte response were investigated. Subsequently, analytical figures of merit, including sensitivity and limits of detection (LOD), were determined under optimum atomization conditions. The sensitivity values ranged between 0.03 and 0.30 s ng^-1, while LODs from 0.1 to 1.5 ng ml^-1 were found. APGD performance, including its resistance to interferences, was compared to that of other hydride atomizers - QTA and DBD.

This research has been supported by the Czech Science Foundation under Contract 23-05974K, by the Charles University Grant Agency (project no. 614225), and by the Czech Academy of Sciences (Institutional research plan RVO:68081715).

Coupling hydride generation with atomic absorption or fluorescence spectrometry is a well-established technique for trace element and speciation analysis, enabling efficient, and matrix-free introduction of analytes into the detector. While heated quartz tube atomizers and diffusion flames remain the most widely used hydride atomizers, alternative plasma-based atomizers - particularly dielectric barrier discharges (DBD) and atmospheric-pressure discharges (APD) - have gained attention. The DBD can efficiently atomize As, Se, Sb, and Bi hydrides while reaching poor sensitivity for Pb, Sn, and Ge. In particular, Ge is detected with low sensitivity even in the most common hydride atomizers.

Consequently, APD-based atomizers were developed and investigated in this work to overcome the low sensitivity observed in DBD for the elements mentioned above (Pb, Sn, Ge). Four APD designs were developed and tested. The first APD construction resembled the design of the diffusion flame, using a quartz capillary nested within a stainless steel anode and an opposing tungsten rod cathode. The zone of atomization was shielded with argon flow to prevent the entrance of oxygen from the ambient atmosphere. However, the discharge was unstable with this construction. The second design, based on two opposite rod electrodes, demonstrated stable discharge and obtained signal was comparable to that of diffusion flames. Thus, this design could be a robust alternative, and it is ready for optimization using an atomic fluorescence spectrometer. The other two APD designs tested were derived from the quartz tube atomizer. In the first arrangement, analyte hydride was introduced through a quartz and stainless steel capillary in a parallel direction with the plasma. In the second arrangement, analyte hydride was introduced through an inlet arm perpendicularly to the plasma and the opposite tungsten rod electrodes. The atomization area was protected from the ambient atmosphere by the optical tube eliminating the need for additional argon. The last design was selected as the most promising, and its performance was compared to the DBD and heated quartz tube atomizer. Current-voltage characteristics were evaluated, as they are crucial parameters for discharge performance. Due to the limited atomization efficiency achieved with commercially available high-voltage and direct current power sources, custom pulsed direct current power sources were developed. Various configuration will be presented.

Moreover, the distribution and absolute concentration of hydrogen radicals/free analyte atoms in the most promising APD design were studied by two-photon/laser-induced fluorescence, and the results will be correlated with atomic absorption spectrometry experiments.

Acknowledgments

This research has been supported by the Czech Science Foundation under contract 23-05974K and by the Institute of Analytical Chemistry of the Czech Academy of Sciences (Institutional Research Plan no. RVO: 68081715).

Hydride generation (HG) is a useful sample derivatization step in trace element analysis being applicable to several analytically and toxicologically important elements including As, Se, Te, Pb, Sn Sb, Bi and Ge. It reaches almost quantitative and matrix-free analyte introduction into the atomic spectrometric detector. Hydride atomizers based on flame, heated quartz tube (QTA) or plasmas are employed in atomic absorption spectrometry (AAS). QTAs are the most common hydride atomizers in AAS offering high sensitivity universally for all hydride forming elements with the only exception of Ge, for which significantly impaired sensitivity is reached. Recently, ambient plasmas such as volume dielectric barrier discharges (DBDs) or atmospheric pressure glow discharge (APGD) have been reported to be an alternative to QTAs. Significant differences in sensitivity were found among individual hydride forming elements in ambient plasma-based hydride atomizers, especially in the DBD, even under atomization conditions optimized individually for each analyte. Since efficient hydride generation, i.e., analyte conversion to a corresponding binary hydride, has been proven for all hydride forming elements investigated in our previous studies, atomization mechanisms and the fate of free analyte atoms were investigated in this work using various advanced spectrometric techniques. Although DBD hydride atomizers offer either the same, or worse sensitivity than QTA, they allow simple and fast in-situ preconcentration of hydrides prior to AAS detection leading to significant LOD improvement.

Laser induced fluorescence (LIF) was employed as a useful diagnostic tool capable of determination of spatial distribution of free analyte atoms in the atomizers, with or without the preceding in-situ preconcentration step, as well as quantifying their absolute concentration, leading to assessment of atomization efficiency. Hydrogen radicals were detected by two-photon absorption LIF (TALIF) as important species responsible for hydride atomization in all types of atomizers. Time-resolved optical emission spectrometry revealed the basic plasma dynamics. The analyte fraction deposited by decay reactions of free atoms at inner surface of the hydride atomizers was quantified by leaching experiments with ICP-MS detection while their morphology and composition were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively.

A detailed insight into the mechanisms of hydride atomization and preconcentration in ambient plasmas has been reached. The results found by these techniques are in perfect agreement with the observations made by AAS. Owing to a comprehensive approach based on a combination of advanced spectrometric methods, further improvements in the performance of DBD and APGD hydride atomizers will be feasible.

Acknowledgements

Financial support from the Czech Science Foundation (23-05974K), Institute of Analytical Chemistry (RVO: 68081715) and MŠMT ČR (LM2023039) is gratefully acknowledged.

Polybetaine nanobrushes are widely used as inert platforms for label-free biosensing due to their resistance to non-specific interactions. Despite being considered cationic or electrically neutral, polybetaines can exhibit negative zeta potential (ZP) ​​at pHs above their isoelectric point (pI). To clarify whether negative zeta potential effectively contributes to surface interactions, we examined three types of nanobrushes deposited on a planar gold substrate: two polybetaines – poly(carboxybetaine methacrylamide) (pCBMAA) and poly(sulfobetaine methacrylamide) (pSBMAA), and hydrophilic poly[N-(2-hydroxypropyl) methacrylamide] (pHPMAA) which carries no ionic group. All three brushes exhibit well defined pI and negative surface ZP at pHs above their pI. The pH dependence of the interactions of these brushes with anionic dextran sulfate (DS) and cationic poly[(N-trimethylammonium)ethyl methacrylate] (PTMAEMA) was monitored by infrared reflection spectroscopies (IRRAS, GAATR). DS adsorbs to pCBMAA strongly and only weakly to pSBMAA at pHs below their pI but can adsorb slightly to both polybetaines even at pHs above their pI. This is due to the displacement of their carboxylate or sulfo groups from interaction with the quaternary ammonium cation by the DS sulfate groups. However, DS does not adsorb to pHPMAA at any pH, and PTMAEMA does not adsorb to any of the brushes, regardless of pH. These findings highlight that zeta potential determinations alone may not be sufficient to predict electrostatic interactions, as the apparent negative charge does not necessarily translate into a functional surface charge influencing macromolecular interactions.

Polaritons are half-light half-matter quasiparticles, resulting from the strong coupling between excitons and cavity modes. Polaritons hold great potential in modifying physical and chemical properties of materials. We show that by coupling molecular excitons in aggregates to surface plasmon polaritons, the resulting exciton-polaritons show enhanced propagation distance to 10 micrometers, much longer than the diffusion length of excitons of less than 1 micrometer. This is due to the unique feature of polaritons, i.e., a high group velocity that is roughly half the speed of light, benefiting from the light component in polaritons. Therefore, even though the lifetime of surface plasmons is only tens of femtoseconds, the propagation distance can be as long as 10 micrometers. We demonstrate that the propagation distance can be manipulated by engineering the lifetime of the surface plasmon modes.

In the second part, we will discuss the ultrafast carrier dynamics of polaritons, which is vital for their optoelectronic applications. Self-hybridized polaritons were formed in a 170 nm thick WSe2 flake on a gold substrate without top mirror, which is absent in a 13 nm thick WSe2. We find that, under different pump excitation energies, significantly different carrier dynamics of lower polariton, upper polariton, and exciton reservoir can be observed. For above bandgap excitation, carriers will be firstly relaxed to exciton reservoir, followed by scattering to lower and upper polaritons in the time scale of 1-100 ps. For low energy excitation, which exclusively excites lower polaritons, reversed scattering from lower polariton to exciton reservoir is seen on the same time scale of 1-100 ps. After that, inter-band relaxation occurs on a longer time scale of hundreds of picoseconds. These results unravel the carrier dynamics of polaritons and exciton reservoir, specifically the important role of inter-state scattering in carrier relaxation in strong coupling systems.

Both, laser induced breakdown spectroscopy (LIBS) and Raman scattering categorically follow the same workflow in which a non-resonant laser is focused tightly onto a sample target while the characteristic emission of the irradiated spot is collected and spectrally analyzed to obtain specific information on the samples’ composition. While LIBS spectra contain the elemental information, Raman spectra holds the specific details about chemical bonds, i.e. molecular information. This pairing of seemingly identical hardware demands on the input demands to obtain highly orthogonal complementary knowledge about the targets’ composition appears a textbook example of spectrochemical synergy. However, in common applications hardware demands regarding lasers (pulsed for LIBS, continuous wave for Raman) and spectrometer ranges (UV for LIBS, NIR for Raman) strongly differ. Also, standard sampling parameters ultimately dictating the scanning pattern in mapping experiments like spot sizes and exposure times are typically two orders of magnitude apart for the two techniques. For instance, 100 µm is a common crater size in LIBS while 1 µm is typical for the Raman irradiation area, LIBS signals are intense and lead to a meaningful spectrum in the matter of tens of milliseconds (ms) while Raman spectra are often accumulated over seconds.

This presentation shows that meaningful compromises in both techniques are not enough to bring the two methods together. However, when applying uncommon and innovative hardware concepts, a single instrumental setup can be realized, which allows to record LIBS and Raman spectra with a common repetition rate and exposure time on the order of ms, both sharing the same laser, scanning pattern and spectrometer. This union was achieved by using ultraviolet diode pumped solid sate lasers in combination with spatial heterodyne spectrometers. While the first are highly flexible in terms of their low prices, their unique quantum efficiency and their flexibility in terms of pulse behaviour, the latter combines the best of traditional diffraction with the light throughput of interferometry. To showcase this novel approach, samples from the lifecycle of lithium-ion batteries are studied. These samples range from pristine electrodes via cycled batteries with early defects all the way to end of life black mass.

The ability to “take aim” and accurately manipulate gas-phase ions is critical to ensure the proper function of ion-based analytical techniques, such as mass spectrometry. Traditionally, ions are focused, gated, redirected, and separated with ion optics, which function analogously to light optics. These components rely on the behavior of charged analytes within electric and/or magnetic fields. However, due to both the complexity of individual devices and the function-specific design of ion optics, there is no single, user-friendly, multi-purpose component for the manipulation of ions at and above rough vacuum pressures. Here, we utilize both charge and fluid behaviors of gas-phase ions at atmospheric pressure as the basis for a novel class of ion optics. Acoustic ion manipulation (AIM) is a newly discovered phenomenon, whereby, in one manifestation, gaseous ions are controlled by dynamic pressure regions in an ultrasonic standing acoustic wave. Inside an acoustic resonator, stable and unstable areas, referred to as nodes and antinodes, respectively, repeat at regular intervals within the standing acoustic wave, which allows a single standing wave to focus or deflect an ion beam based on alignment. As such, a standing acoustic wave is able to perform four classes of ion optic functionality (i.e. focusing, gating, redirection, and separation) without any additional changes to the acoustic field.

In this work, we demonstrate the function of a standing acoustic wave as an ion optic at atmospheric pressure in the absence of external electric fields. Experimentally, beams of ions were generated with plasma-based or electrospray-based ionization sources and were aligned with the inlet of a mass spectrometer. A standing acoustic wave was generated in the ion beam path and was moved so that either a node or antinode would interact with the gas-phase ions before detection. When a node was present in the ion flow, a signal enhancement of 2-3 times was observed due to acoustic focusing. In contrast, when the antinode was aligned with the ion beam, the standing wave acted as a gate and ion signal decreased by more than 99.9%. This decrease is attributed to the deflection of the ion beam away from the mass spectrometer inlet. Characterization of the ion-beam profile with an IonCCD showed a 2-mm displacement along the axis of acoustic propagation upon the ions interacted. This change in position reflected the structure of the standing acoustic wave, where nodes are located λ/4 above and below the center of the antinode, with λ indicating the wavelength of sound. As such, antinodes redirect ion beams to preferentially pass through the stable regions within the acoustic field. Lastly, ion-specific properties such as mass-to-charge ratio, collisional cross section, or charge state lead to ion separation by impacting the efficacy of acoustic-ion interactions. In one example, ions with lower mass-to-charge ratios were more effectively displaced than larger species. Additionally, higher charge-state protein ions were more susceptible to acoustic deflection as compared to lower charge-state counterparts. The development of an acoustically based ion optic could have far-reaching impacts on mass spectrometry, as well as ex vacuo methods for ion control.

Laser-Induced Breakdown Spectroscopy (LIBS) is typically regarded for its simplicity and applicability for the direct analysis of samples of any kind, including liquids. However, these matrices are challenging and often require the development of more or less intricate sampling strategies and/or instrumental modifications in order to reach the required levels of stability, reproducibility and sensitivity. Hence, its application to liquids remains scarce in comparison to the vast variety of solid samples focused works.

On the other hand, it is well known that halogens pose a challenge of their own when determined via OES techniques, as their resonant emission lies within the VUV. Aside from signal enhancement approaches (such as double-pulse LIBS), a common approach to halogen determination is the indirect detection through halide molecule emission resulting from the recombination of the halogen of interest and an alkali-earth metal element, such as calcium.

Previous works [1,2] have demonstrated the feasibility of halogen determination (F, Cl) in aqueous liquid matrices by depositing the sample on a Ca-containing target (calcium carbonate pellets, paper) online via nebulization of the former, with limits of detection varying from 5 ppm (F) to 200 ppm (Cl). Real samples such as mouthwashes were successfully evaluated, but a particularly interesting case was the study of an aqueous dilution of a fluorosurfactant, where total fluorine content could be determined with similar results as those obtained from solutions of an inorganic fluorine salt. Such outcome implies that prior knowledge of the organic/inorganic state of halogen compounds might not be critical in LIBS analyses (as it is the case, for example, in ionic chromatography). These results motivated the investigation focused on organic samples, particularly focusing on gasolines. The research focused on halogen determination in liquid samples of inorganic and organic form will be overviewed in this talk.

[1] C. Méndez-López et al. (2023) J. Anal. At. Spectrom., 38, 80-89.

[2] C. Méndez-López et al. (2023) Opt. Laser Technol., 164, 109536.