Optimized method avoiding solvent-induced response enhancement in the analysis of volatile and semi-volatile polyfluorinated alkylated compounds using gas chromatography–mass spectrometry

A method for the analysis of airborne (semi-)volatile polyfluorinated alkyl substances (PFASs) was optimized to avoid solvent-induced response enhancements as observed using ethyl acetate as extraction solvent (recoveries up to 300%, likely due to acetic acid as impurity). Of nine solvents tested, only the use of acetone, dichloromethane, methyl tert-butyl ether, and acetone:petroleum ether (1:1, v/v) resulted in recoveries below 100% and acetone:methyl tert-butyl ether (1:1, v/v) was chosen as suited extraction solvent. An appropriate GC capillary column and the application of mass-labelled internal standards appeared to be essential for these analyses. Instrumental limits of detection of <0.2 pg (dimethylperfluoroocatanesulfonamide, ethyl-[2H5]perfluorooctanesulfonamide, methyl-[2H3]perfluorooctanesulfonamide) to 8.2 pg (perfluorooctanesulfonamide) and LOQ of 0.4 pg (dimethylperfluoroocatanesulfonamide, ethyl-[2H5]perfluorooctanesulfonamide, methyl-[2H3]perfluorooctanesulfonamide) to 16.4 pg (perfluorooctanesulfonamide) were determined.