Gas chromatography-tandem mass spectrometry with atmospheric pressure chemical ionization for fluorotelomer alcohols and perfluorinated sulfonamides determination

Abstract

Ionization and in source-fragmentation behavior of four fluorotelomer alcohols (FTOH) (4:2 FTOH, 6:2FTOH, 8:2 FTOH and 10:2 FTOH) and four N-alkyl fluorooctane sulfonamides/-ethanols (N-MeFOSA, N-EtFOSA, N-MeFOSE and N-EtFOSE) by APCI has been studied and compared with the traditionally usedEI and CI. Protonated molecule was the base peak of the APCI spectrum in all cases giving the possibilityof selecting it as a precursor ion for MS/MS experiments. Following, CID fragmentation showed commonproduct ions for all FOSAs/FOSEs (C4F7and C3F5). Nevertheless, the different functionality gave charac-teristic pattern fragmentations. For instance, FTOHs mainly loss H2O + HF, FOSAs showed the losses ofSO2and HF while FOSEs showed the losses of H2O and SO2. Linearity, repeatability and LODs have beenstudied obtaining instrumental LODs between 1 and 5 fg. Finally, application to river water and influentand effluent waste water samples has been carried out in order to investigate the improvements in detec-tion capabilities of this new source in comparison with the traditionally used EI/CI sources. Matrix effectsin APCI have been evaluated in terms of signal enhancement/suppression when comparing standardsin solvent and matrix. No matrix effects were observed and concentrations found in samples were inthe range of 1-100 pg L−1far below the LODs achieved with methods previously reported. Unknownrelated perfluoroalkyl substances, as methyl-sulfone and methyl-sulfoxide analogues for FTOHs, werealso discovered and tentatively identified.