Purification and Preconcentration of Per- and Polyfluoroalkyl Substances (PFAS) by HPLC Fraction Collection for Isotope Analysis

Stable isotope data are increasingly used for environmental forensics and source apportionment studies. The latest chemical pollutant landscape being explored using environmental forensics is per- and polyfluoroalkyl substances (PFAS). Due to a variety of methodological difficulties, isotopic analysis of PFAS for environmental forensic purposes is in its nascent stages. In a previous study, the authors presented the analytical methodology for measuring the stable carbon isotopic composition of a model PFAS: perfluorooctanoic acid (PFOA). This study presents the complementary method for the purification and preconcentration of PFOA for isotopic analysis. It demonstrates that the method yields accurate and precise δ 13 C values in environmental PFAS samples. This novel method demonstrates the utility of high-pressure liquid chromatography (HPLC) fraction collector isolation of PFAS for stable isotopic analysis by Orbitrap mass spectrometry. This study additionally presents the first compound-specific stable isotope data of a PFAS compound from an environmental sample.