52: Real-time opto-electrochemical PFAS sensing at low ppt concentration

Abstract: Per- and polyfluoroalkyl substances (PFAS) contamination in water is an increasing concern as adverse human health effects have been associated with exposure even at low parts-per-trillion (ppt) levels. Current low-level PFAS detection methods are largely restricted to laboratory techniques such as liquid or gas chromatography coupled with mass spectrometry, which require expensive instrumentation and substantial sample preparation. Field-deployable approaches capable of low-level PFAS detection remain limited. The Environmental Optically Gated Transistor (ENVIR-OGT) is a simple-to-fabricate semiconductor sensor for low-concentration analyte detection. Using transient optoelectronic measurements together with a machine learning pipeline, the ENVIR-OGT enables chemical identification from measured response signatures. Results demonstrate detection and differentiation of a broad range of PFAS, from ultra-short-chain compounds to PFOA and L-PFOS, at low ppt concentrations, highlighting the potential of this platform for low-cost and field-deployable PFAS monitoring.