Rapid Screening and Quantification of PFAS Enabled by SPME-DART-MS

Per- and polyfluoroalkyl substances (PFAS), an emergingclass oftoxic anthropogenic chemicals persistent in the environment, are currentlyregulated at the low part-per-trillion level worldwide in drinkingwater. Quantification and screening of these compounds currently relyprimarily on liquid chromatography hyphenated to mass spectrometry(LC-MS). The growing need for quicker and more robust analysis inroutine monitoring has been, in many ways, spearheaded by the adventof direct ambient mass spectrometry (AMS) technologies. Direct analysisin real time (DART), a plasma-based ambient ionization technique thatpermits rapid automated analysis, effectively ionizes a broad rangeof compounds, including PFAS. This work evaluates the performanceof DART-MS for the screening and quantification of PFAS of differentchemical classes, employing a central composite design (CCD) to betterunderstand the interactions of DART parameters on their ionization.Furthermore, in-source fragmentation of the model PFAS was investigatedbased on the DART parameters evaluated. Preconcentration of PFAS fromwater samples was achieved by solid phase microextraction (SPME),and extracts were analyzed using the optimized DART-MS conditions,which allowed obtaining linear dynamic ranges (LDRs) within 10 and5000 ng/L and LOQs of 10, 25, and 50 ng/L for all analytes. Instrumentalanalysis was achieved in less than 20 s per sample.