Simultaneous determination of perfluorooctane sulfonate and perfluorooctanoic acid isomers by HPLC-MS/MS

A method was established for simultaneous determination of perfluorooctane sulfonate and perfluorooctanoic acid isomers in environmental sample by using high performance liquid chromatography-tandem mass spectrometry coupled with solid phase extraction (SPE-HPLC-MS/MS). The WAX SPE cartridge was used for samples' enrichment and clean-up, then followed by determination by HPLC-MS/MS in negative electrospray ionization and multiple reaction monitoring (MRM) mode. The separation was achieved with an Ascentis® Express F5 PFP column with mobile phases of A, methanol and B, 60 mmol·L-1 NH4OH/20 mmol·L-1 formic acid aqueous solution. The established method was used for the analyses of water, sediment and shellfish samples. The method detection limits(S/N=3) were in the range of 0.05—1.1 ng·L-1, 0.025—0.56 ng·g-1 and 0.025—0.56 ng·g-1, respectively. Satisfactory results were obtained with the recoveries of PFASs isomers in the range of 90.8%—127%, 74.0%—124% and 76.7%—113%, and the relative standard deviations (RSD, n=5) in the range of 5.9%—17.2%, 2.5%—17.0% and 3.30%—11.5%, respectively.