Simultaneous qualitative and quantitative analysis of fluoroalkyl sulfonates in riverine water by liquid chromatography coupled with Orbitrap high resolution mass spectrometry

• Simultaneous qualitative and quantitative analysis of PFSAs by Orbitrap was tested.
• Quantification of PFOS isomers based on full-scan MS1 chromatogram.
• Competent linear dynamic range and sensitivity were found in the HRMS method.
• Accurate mass measurement had advantage on elimination of environmental interferent.
• High proportions of the emerging 6:2Cl-PFAES were found in riverine water samples.

In this study, a robust method for quick screening, confirmation and quantification analysis of eight fluoroalkyl sulfonates in surface riverine samples was developed using ultra-high performance liquid chromatography-high resolution mass spectrometer (LC-Orbitrap Tribrid HRMS). Weak anion exchange solid phase extraction was optimized to maximum recover perfluoroalkyl sulfonates (PFSAs), fluorotelomer sulfonates and the emerging 6:2 chlorinated polyfluoroalkyl ether sulfonate at the same time. Both qualitative and quantitative purposes could be achieved by simultaneous acquiring full-scan mass spectrum (MS1) and data-dependent MS2 data. The LC-Orbitrap Tribrid HRMS method showed competent method detection limits for all analytes (7.1–62 pg/L) compared with the triple quadrupole mass spectrometry (LC–MS/MS) quantification method (12–54 pg/L), and satisfactory method validation results were also obtained in linearity (R2 > 0.999), trueness (88–118%), precision (2–17%) and recovery (63–103%). A good correlation (R > 0.999) was found between the sets of quantified PFSA residue concentrations in thirteen estuary river samples by both the LC-Orbitrap Tribrid HRMS (0.2–440 ng/L) and LC–MS/MS (0.1–424 ng/L) methods, indicating that Orbitrap Tribrid HRMS could be used for reliable quantitative analysis purpose. Moreover, the LC-Orbitrap Tribrid HRMS method could also benefit from its high mass resolution characteristic to eliminate potential environment interferents (e.g., taurodeoxycholate) and to quantify all PFSA isomers based on full-scan MS1 chromatogram at a narrow MS window (5 part per million).