Zwitterionic, cationic, and anionic perfluoroalkyl and polyfluoroalkyl substances integrated into total oxidizable precursor assay of contaminated groundwater
| Autor: | Jinxia Liu, Sandra Mejia-Avendaño, Yuan Yao, Carl E. Brown, Gabriel Munoz, Sung Vo Duy, Déborah Martin, Sébastien Sauvé, Konstantin Volchek |
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| Rok vydání: | 2018 |
| Předmět: |
010401 analytical chemistry
Cationic polymerization 02 engineering and technology 021001 nanoscience & nanotechnology Persulfate 01 natural sciences 6. Clean water 0104 chemical sciences Analytical Chemistry chemistry.chemical_compound Betaine chemistry 13. Climate action Environmental chemistry Groundwater pollution Amine gas treating Methanol 0210 nano-technology Fluorotelomer Perfluorohexane |
| Zdroj: | Talanta. 195 |
| ISSN: | 1873-3573 |
| Popis: | The total oxidizable precursor (TOP) assay can be useful for integrating precursors to perfluoroalkyl acids (pre-PFAAs) into the assessment of sites contaminated by per- and polyfluoroalkyl substances (PFAS). Current research gaps include risks of instrumental matrix effects due to the complexity of post-oxidation extracts, potential reproducibility issues during TOP itself, and limited information for zwitterionic and cationic pre-PFAAs. We first investigated a suitable method for the analysis of groundwater samples, using liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). Initial sample pre-treatment through filtration could affect the dissolved PFAS concentrations and was therefore avoided. Amending the postoxidation samples with methanol allowed for improved precision and low instrumental matrix effects. We also documented the oxidation yields of 23 anionic, neutral, zwitterionic, and cationic precursor compounds of PFAAs. These precursor compounds were amenable to TOP conversion. The total oxidative yield of 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB), for instance, was 80 mol%, with C3-C5 PFCAs as major oxidation products (minor: C6-C7 PFCAs). The method was applied to determine a wide range of PFAS (n = 41) without oxidation as well as ΔPFCA via persulfate oxidation in AFFF-impacted groundwater samples from fire-equipment testing sites in Ontario and Newfoundland, Canada. Summed PFAS concentrations as high as 5 mg L−1 were reported before oxidation, and post-oxidation increases of PFCAs up to + 2300% were observed. A significant contribution of increases in individual PFCAs was attributed to precursors such as 6:2 FTAB, fluorotelomer sulfonates (6:2 FtS, 8:2 FtS), perfluorooctane sulfonamidoalkyl amine (PFOSAm), and perfluorohexane sulfonamide (FHxSA) at the active firefighting training site. |
| Databáze: | OpenAIRE |
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