Applicability of mixed-mode chromatography for the simultaneous analysis of C1-C18 perfluoroalkylated substances

• Published in: Analytical and bioanalytical chemistry 2020-08, Vol.412 (20), p.4849-4856
• Main Authors: Montes, Rosa, Rodil, Rosario, Placer, Lorena, Wilms, Jonas M., Cela, Rafael, Quintana, José Benito
• Format: Article
• Language: English
• Subjects: Acids; Ammonia; Analytical Chemistry; Anion exchange; Anion exchanging; Biochemistry; Cartridges; Chains; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chromatography; Contamination; Evaporation; Food Science; Ions; Laboratory Medicine; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Methanol; Monitoring/Environmental Analysis; Perfluoro compounds; Persistent and Mobile Organic Compounds – An Environmental Challenge; Research Paper; Rivers; Solid phases; Trifluoroacetic acid; Water analysis; Water sampling
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-020-02434-w

A new analytical method for the determination of 22 perfluoroalkylated (carboxylic and sulfonic) acids in water samples is presented. The method’s objective was to achieve the simultaneous quantification of compounds with different chain lengths (from C 1 to C 18 ). To this end, 500 mL of water were extracted with Oasis WAX solid-phase extraction cartridges and eluted with 3 mL of 5% ammonia in methanol. After evaporation to dryness, extracts were reconstituted in methanol:ultrapure water (1:1) and analyzed by mixed-mode liquid chromatography-tandem mass spectrometry (MMLC-MS/MS) using a weak anion exchange/reversed-phase column. The method provided good results, with limits of quantification lower than 1 ng/L in river water for most of compounds, except the two perfluorocarboxylic acids with the longest alkyl chain (>C 14 ) and trifluoroacetic acid, for which a blank contamination problem was observed. The method proved good trueness and precision in both ultrapure and river water (R ≥ 81%, RSD ≤ 15%). After validation, the method was applied to the analysis of nine water samples where nine perfluoroalkylated acids were quantified. Seven of them were ultrashort- (C 1 -C 4 ) and short-chain (C 4 -C 8 ) perfluoroalkylated acids, pointing out the importance of developing methods capable to target such substances for further monitoring.