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Investigating the impact of the liquid chromatography method on NTA identification of short-chain PFAS in industrial samples
Citation:
Bangma, J., M. Strynar, J. McCord, AND J. Koelmel. Investigating the impact of the liquid chromatography method on NTA identification of short-chain PFAS in industrial samples. SETAC Europe 2023, NA, Dublin, IRELAND, April 30 - May 04, 2023.
Impact/Purpose:
AS PFAS producers create more short chain replacement PFAS, altering the method to target short chain PFAS may improve Identification of these novel short chain PFAS. This study investigates if altering chromatography parameters increase the ease and Identification of short-chain PFAS.
Description:
Per- and polyfluorinated substances (PFAS) are a class of thousands of unique chemicals containing carbon-fluorine bonds. Due to their widespread and decades-long usage, many PFAS are globally detectable in environmental media, wildlife, and humans. The most investigated PFAS to date are PFOA and PFOS. Yet, in recent decades, many applications of PFAS have transitioned to using shorter-chain replacement compounds. While some short-chain compounds have been identified (e.g., PFBA), emerging short-chain PFAS are still a concern and often require the use of high-resolution mass spectrometry (HRMS) and non-target analysis (NTA) techniques for identification. Many current reversed-phase liquid chromatography (LC) methods used to investigate PFAS result in short-chain PFAS eluting from columns within or close to the column’s dead volume. This results in a variety of drawbacks including little to no chromatographic separation of isomers, ion suppression from matrix effects, and an increase in in-source artifacts. As the industrial production and application of short-chain PFAS are on the rise, it is important to optimize LC methods for the identification of emerging short-chain PFAS. In this study, industrially contaminated water samples from across the US were isolated using a WAX extraction method and analyzed in triplicate with either a standard reversed-phase C18 column with a ramping gradient (25:75 aqueous: organic starting gradient) or a dual-phase column with an isocratic gradient (60:40 acetonitrile: methanol) in line with a high-resolution quadrupole time-of-flight instrument. Agilent Profinder was used for feature finding and FluoroMatch was used for visualization, grouping (via homologous series detection), annotation (via accurate mass and diagnostic fragment ion matching), and scoring. All data processing steps and FluoroMatch settings were maintained across experiments, and results were manually confirmed whenever possible. Results revealed that the dual-phase column resulted in increased retention of short chain compounds, improved compound separation, and improved identification of emerging short chain PFAS.
