Can qualitative non-target data be indicative of PFAS contamination? First evidence by correlation with EOF in environmental samples

We combined and correlated non-target screening (NTS) features and extractable organic fluorine (EOF) data for PFAS analysis in environmental samples. Soils, sediments, and ashes from different locations (Germany, France, Lithuania) (n=34) were extracted and analyzed via liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). NTS feature prioritization based on the mass to carbon (m/C) and mass defect to carbon (MD/C) ratio was applied to discriminate potential PFAS features from common co-extracted organic matrix. Our results show a high correlation between quantitative EOF data with the prioritized feature number (R2 = 0.87, rPearson = 0.93) as well as with the total peak area of prioritized features (R2 = 0.97, rPearson = 0.98) while commonly applied MD filtering showed no correlation with EOF. The observed highly significant correlations highlight that MD/C-m/C prioritization is associated with a good indication of the overall PFAS burden as evidenced by EOF. Also, semi-quantitative data can be extracted from PFAS-specific NTS as shown for the EOF vs. prioritized peak areas. The correlations indicate that lowly fluorinated compounds were negligible and that the EOF was mostly composed of higher fluorinated substances. We recommend further investigation of the unique complementary EOF vs. NTS combination for PFAS screening.