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The use of pentafluorobenzyloxime–trimethylsilyl derivatives in the analysis of corticosteroids by gas chromatography/negative ion chemical ionization mass spectrometry
Author(s) -
Midgley J. M.,
Watson D. G.,
Healey T.,
McGhee C. N. J.
Publication year - 1989
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200180904
Subject(s) - chemistry , derivatization , trimethylsilyl , chemical ionization , reagent , mass spectrometry , chromatography , gas chromatography , gas chromatography–mass spectrometry , mass spectrum , hydroxylamine , ion , ionization , organic chemistry
Pentafluorobenzyl hydroxylamine has been used as a derivatization reagent in the analysis of corticosteroids by gas chromatography/negative ion chemical ionization (GC/NICI) mass spectrometry. The resulting pentafluorobenzyloxime‐trimethylsilyl (PFBO/TMS) derivatives were generally formed in moderate yield but, despite this, the use of these derivatives resulted in a ∼ 10‐fold improvement in the capability of identification of corticosteroids by GC/NICI mass spectrometry in comparison with the methoxime/TMS derivatives previously employed. The NICI mass spectra of PFBO/TMS derivatives were simple, with most of the ion current being carried by the [M – C 6 F 6 CH 2 ] −. or [M – PFB] −. ion and by a reagent‐specific peak at m/z 196. The derivatives have been employed in the quantification of ∼400 pg amounts of endogenous hydrocortisone present in samples of human aqueous humour and are readily applicable to the determination of low‐picogram amounts of these compounds in biological media.