Application of photothermal analytical techniques for ultra-sensitive environmental sensing

Research conducted at LELS demonstrated scientific excellence in the development and application of advanced photothermal analytical techniques for ultra-sensitive environmental sensing and characterization of complex environmental matrices. The work advanced methodological approaches in thermal lens spectrometry, thermal lens microscopy and photothermal beam deflection spectrometry for the sensitive detection and spatial characterization of environmentally relevant chemical species.

The work contributed methodological advances in sensitive photothermal methodologies applicable to challenging environmental and aquatic systems. The research demonstrated the successful integration of thermal lens microscopy with microfluidic flow injection analysis for sensitive detection of microcystin-LR in water, iron species in cloud water and ammonium in small-volume environmental samples. In parallel, photothermal beam deflection spectrometry was combined with diffusive gradients in thin films for two-dimensional characterization of iron species distribution in sea ice and aquatic systems.

The achievement contributed to methodological advances in environmental analytical chemistry by improving sensitivity, spatial resolution and applicability of photothermal techniques in complex environmental matrices. The developed approaches provide important analytical tools for environmental monitoring and characterization of pollutants, nutrients and trace chemical species in aquatic and environmental systems.

The achievement strongly supports the university’s strategic priorities in Scientific Excellence, Interdisciplinary Research and Societal Relevance through the integration of analytical chemistry, environmental science, photonics and microfluidic technologies for environmentally relevant applications. Internationalization was strengthened through international collaborations, invited lectures and broad international dissemination of the research.

The work resulted in publications and invited presentations with substantial visibility within the analytical and environmental sensing communities. The 2023 publication in Sensors, coordinated by Prof. Dr. Mladen Franko and Assoc. Prof. Dr. Dorota Korte, was recognized by the Editors-in-Chief as a noteworthy contribution highlighting important advances in the field. The research has subsequently supported further methodological developments and applications in environmental and aquatic systems, including studies on microplastic detection and iron speciation analysis. A remaining challenge is the transfer of photothermal methodologies from controlled laboratory settings into routine field-deployable environmental monitoring platforms.

• Franko M, Goljat L, Liu M, Budasheva H, Žorž M, Korte D (2023). Recent progress and applications of thermal lens spectrometry and photothermal beam deflection techniques in environmental sensing. Sensors 23(1):1–17.
• Abraham PA, Gokula V, Swapna MNS, Sankararaman SI (2024). Thermal lens technique's surrogacy unveiled: A novel tool for microplastic detection and quantification in water. Heliyon 10(14).
• Budasheva H, Swapna MNS, Bratkič A, Sankararaman SI, Korte D (2024). Unveiling labile iron speciation in aquatic systems: Depth binding profiles in chelex-based resin hydrogels using diffusive gradients in thin films – Beam deflection spectrometry. Microchemical Journal 197:109826.