Closing PFAS analytical gaps: Inter-method evaluation of total organofluorine techniques for AFFF-impacted water
Fuhar Dixit, Edmund H. Antell, Katharine A. Faber, Chuhui Zhang, Manmeet W. Pannu, Megan H. Plumlee, Jean Van Buren, Abraham Doroshow, William C. K. Pomerantz, William A. Arnold, Christopher P. Higgins, G. F. Peaslee, Lisa Alvarez‐Cohen, David L. Sedlak, Mohamed Ateia
Abstract
Multiple poly- and perfluoroalkyl substances (PFASs) are present in aqueous film-forming foams (AFFF) used for firefighting activities. Currently, no single analytical technique provides a complete accounting of total PFASs or total organofluorine content in AFFF-contaminated samples. To provide insight into the performance of existing methods, we compared ten previously described PFAS measurement techniques. In AFFF-amended tap water, US EPA Methods 533 and 1633, adsorbable organic fluorine with particle induced gamma emission spectroscopy (AOF-PIGE) and fluorine-19 nuclear magnetic resonance ( 19 F NMR) provided similar estimates of total fluorine. The total oxidizable precursor (TOP) assay, suspect screening, and adsorbable organic fluorine with combustion ion chromatography (AOF-CIC) yielded estimates of total organic fluorine that were about two to three times higher than the other techniques. Proximate to AFFF sources, suspect screening and modified EPA Method 1633 yielded higher results, while the TOP assay results were between the other two sets of analyses. Further from sources, suspect screening, modified EPA Method 1633, and the TOP assay yielded similar results that were 4-fold higher than results from targeted quantification methods, such as EPA Method 1633. These results are consistent with expectations about PFAS behavior and inform the selection of analytical techniques used for PFAS contamination characterization efforts. • Suspect Screening and TOP Assay estimate higher organofluorine than target methods. • AOF-CIC variability limits low ng/L sample detection (500-fold concentration). • TOP Assay, AOF-PIGE and 19 F NMR, need better sample preconcentration methods. • Suspect screening relies on representative surrogates. • Enhanced target list improves organofluorine recovery from weathered AFFF.