Quantification of long–chain, short–chain, and ultrashort–chain liquid chromatography–amenable PFASs in water: Evaluation of approaches and tradeoffs for AFFF–impacted water

The widespread use of aqueous film–forming foam (AFFF) for firefighting and firefighter training has led to extensive per– and polyfluoroalkyl substance (PFAS) contamination in the environment. Challenges remain in the analytical determination of PFASs via liquid chromatography–mass spectrometry (LC–MS), particularly when attempting to include ultrashort–chain perfluoroalkyl acids (PFAAs) and longer–chain anionic and zwitterionic PFASs in a single direct injection. In this study, we assessed the performance of three analytical LC columns (C18, JJ, and Acclaim columns) to separate targeted and suspect PFASs in AFFF–impacted water samples collected from five sites. The C18 column failed to retain ultrashort–chain PFAAs while the JJ and Acclaim columns were not suitable for hydrophobic PFASs. Ultrashort–chain PFAAs were detected at three sites and comprised 1.6–18% of the total perfluoroalkyl carboxylic and sulfonic acids. Semi–quantified concentrations of suspect PFASs comprised 0.70–13% of the total PFASs. When attempting to capture the entirety of the PFAS mass in a water sample, the C18 column captured the broadest suite of suspect PFASs, while the JJ column quantified the most total PFAS mass. Results of this study highlight the importance and tradeoffs of LC column choice to comprehensively determine the composition of PFASs and their concentrations in AFFF–impacted water samples.