GNPS AFFF 3M Light Water Non-Targeted PFAS Analysis for FluoroMatch 2.0 Manuscript - Agilent Q-TOF

Because of the pervasiveness, persistence, and toxicity of per- and polyfluoroalkyl substances (PFAS), there is growing concern over PFAS contamination, exposures, and health effects. The diversity of potential PFAS is astounding, with nearly 10,000 catalogued in databases to date (and growing). The ability to detect the thousands of known PFAS, and discover previously uncatalogued PFAS, is necessary to understand the scope of PFAS contamination and to identify appropriate remediation and regulatory solutions. Current non-targeted methods for PFAS analysis require manual curation and are time-consuming, prone to error, and not comprehensive. FluoroMatch Flow 2.0 is the first software to cover all steps of data processing for PFAS discovery in liquid chromatography high resolution tandem mass spectrometry samples. These steps include feature detection, feature blank filtering, exact mass matching to catalogued PFAS, mass defect filtering, homologous series detection, retention time pattern analysis, class-based MS/MS screening, fragment screening, and predicted MS/MS from SMILES structures. In addition, a comprehensive confidence level criterion is implemented to help users understand annotation certainty and integrate various layers of evidence to reduce overreporting. Applying the software to aqueous film forming foam analysis, we discovered over one thousand likely PFAS including previously unreported species. Furthermore, we were able to filter out 96 percent of features which were likely not PFAS. FluoroMatch Flow 2 increased coverage of likely PFAS by over tenfold compared to the previous release. This software will enable researchers to better characterize PFAS in the environment and in biological systems.

An aliquot of a mixed AFFF product collected from a holding tank at a field site in 1999 was prepared by 100,000x dilution in 70:30 water:methanol (Fisher Scientific Optima LCMS-grade). Blanks consisting of 70:30 water:methanol were run before and after AFFF injections. The AFFF sample was characterized previously and is known to contain primarily electrochemically-fluorinated 3M Light Water AFFF mixed with some fluorotelomer-based AFFF. This AFFF sample is representative of mixtures that are widespread at historical AFFF-contaminated sites. The diluted sample was injected four times for iterative exclusion information-dependent analysis (Iterative MS/MS) at 50 uL onto an Agilent 1290 Infinity II ultra-high performance liquid chromatography (UHPLC) system connected to an Agilent 6545 quadrupole time-of-flight mass spectrometer (Q-TOF MS).