Surface-enhanced Raman spectroscopic (SERS) sensors for emerging contaminant analysis in drinking water supplies
Our research advances the development of surface-enhanced Raman spectroscopy (SERS) sensors for rapid, sensitive, and field-deployable detection of emerging contaminants (ECs) in drinking water. Addressing the limitations of conventional analytical methods, we have demonstrated SERS-based quantification of neonicotinoids at sub-part-per-billion levels in complex environmental matrices. Our work includes developing internal-standard-free detection methods, establishing thermodynamic models linking adsorption and SERS signals, and building the first reproducible Raman spectral library for PFAS. These innovations collectively transform SERS into a robust platform for real-time EC monitoring, with future efforts focused on integrating portable hardware and AI-driven analytics to support autonomous water quality monitoring.
Quantification of low-micrometer microplastics and nanoplastics in the Great Lakes
Our research develops advanced analytical platforms for quantifying low-micrometer microplastics (LMMPs) and nanoplastics (NPs) in the Great Lakes, addressing critical challenges in sensitivity, specificity, and environmental matrix interference. We have introduced integrated membrane-Raman systems—including fractionated membrane filtration, plasmonic sensing membranes, and regenerable AAO substrates—combined with data-driven spectral analysis to enable reliable detection of plastic particles as small as 300 nm at environmentally relevant concentrations. These innovations support rapid, in-situ quantification of MPs and NPs across diverse water conditions and lay the groundwork for scalable monitoring solutions to inform plastic pollution management and public health protection in freshwater systems.
Redox reactions on plasmonic nanoparticles for environmental sensing
Our research harnesses redox-active plasmonic nanoparticles to transform passive sensing into active, real-time environmental monitoring of pollutant transformation processes. We developed oxidative ligand exchange strategies and plasmonic colorimetry to enable SERS-based detection of low-affinity pollutants and to quantify polymerization kinetics during advanced oxidation processes. By coupling SERS with time-resolved radical generation and enzyme-mediated redox reactions, we revealed dynamic surface transformations that correlate with contaminant reactivity in both water and soil matrices. These innovations establish a new class of reactive-surface-enabled spectroscopy, advancing the understanding of redox chemistry in environmental systems and laying the foundation for field-deployable diagnostics that integrate plasmonic sensing with data analytics for drinking water and soil monitoring.
Our research is supported by the National Science Foundation, Environmental Protection Agency, Department of Defense, National Oceanic and Atmospheric Administration, Wisconsin Alumni Research Foundation, and the United States Department of Agriculture.
