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Mass spectral studies of perfluorooctane sulfonate derivatives separated by high‐resolution gas chromatography
Author(s) -
Langlois Ingrid,
Berger Urs,
Zencak Zdenek,
Oehme Michael
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3241
Subject(s) - chemistry , derivatization , electron ionization , mass spectrometry , chromatography , reagent , gas chromatography , chemical ionization , mass spectrum , fragmentation (computing) , resolution (logic) , ionization , organic chemistry , ion , artificial intelligence , computer science , operating system
Abstract The mass spectral characteristics of perfluorooctane sulfonate (PFOS, C 8 F 17 SO 3 − ) isomers present in technical PFOS were obtained using high‐resolution gas chromatography (HRGC) combined with mass spectrometry (MS). To make PFOS amenable to HRGC separation, a simple derivatization procedure was developed. The method involved the conversion of PFOS into the iso ‐propyl ester using iso ‐propanol as the derivatization reagent under acidic conditions. Mass spectra were generated employing electron ionization (EI) and negative chemical ionization (NCI). Interpretation of fragment ions was possible due to the use of deuterium‐labeled iso ‐propanol as derivatization reagent, which induced mass shifts in the electron ionization (EI) and negative chemical ionization (NCI) mass spectra. HRMS allowed the accurate mass measurement of important EI fragments and confirmed the derivatization reaction as well as the proposed fragmentation pathway involving rearrangement. Moreover, the high resolution provided by HRGC enabled the separation of eleven PFOS isomers present in the technical product. This is an improvement over the previously reported high‐performance liquid chromatography (HPLC) separation. A complete identification of all isomers was not possible due to lack of pure reference materials. Finally, the developed derivatization procedure was successfully applied to perfluoroalkyl carboxylates (PFCA) and corresponding fragmentation involving rearrangement of the derivatized PFCA was observed. The described qualitative derivatization offers a promising alternative technique for the separation and identification of isomers of perfluoroalkyl sulfonates and carboxylates by HRGC/MS. Copyright © 2007 John Wiley & Sons, Ltd.