Analysis of hydrophilic per- and polyfluorinated sulfonates including trifluoromethanesulfonate using solid phase extraction and mixed-mode liquid chromatography-tandem mass spectrometry

Ultra-hydrophilic perand polyfluorinated sulfonates (PFSA) are increasingly scrutinized in recent years due to their ubiquitous occurrence, persistence, and aqueous mobility in the environment, yet analysis remains a challenge. This study developed methods for the analysis of trifluoromethanesulfonate, perfluorobutanesulfonate, 10-camphorsulfonate, and a di-fluorinated sulfonate utilizing mixed-mode liquid chromatography, where all analytes were adequately retained and separated. Chromatography and electrospray ionization parameters were optimized; instrumental limits of quantification for the anionic target analytes were in the range of 4.3 - 16.1 ng L-1. Solid phase extraction (SPE) methods were developed using Oasis WAX cartridges; SPE recoveries for the analytes ranged from 86% to 125%. Salinity and total organic carbon both impaired the SPE performance to different extents, depending on the respective analyte. Utilizing widely accessible instrumentation and materials, this is a single method to simultaneously analyze conceivably the most hydrophilic PFAS chemical, i.e., trifluoromethanesulfonate, and moderately hydrophobic PFSAs. (C) 2022 Published by Elsevier B.V.

Automated summary

Ultra-hydrophilic perand polyfluorinated sulfonates (PFSA) are a topic of increasing concern due to their widespread presence, persistence, and mobility in water environments. This study developed a method for analyzing trifluoromethanesulfonate, perfluorobutanesulfonate, 10-camphorsulfonate, and a di-fluorinated sulfonate using mixed-mode liquid chromatography. The method successfully retained and separated all target analytes, and solid phase extraction was used for sample purification. The method allows for simultaneous analysis of the most hydrophilic PFAS chemical, trifluoromethanesulfonate, and moderately hydrophobic PFSAs. The optimized method has low instrumental limits of quantification and high recovery rates.