Premium
Electron ionization mass spectrometry fragmentation pathways of trimethylsilyl derivatives of isomeric allylic alcohols derived from HBI alkene oxidation
Author(s) -
Rontani JeanFrançois,
Belt Simon T.,
Brown Thomas A.,
Aubert Claude
Publication year - 2014
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.6974
Subject(s) - chemistry , allylic rearrangement , alkene , fragmentation (computing) , trimethylsilyl , electron ionization , tandem mass spectrometry , mass spectrometry , chemical ionization , organic chemistry , medicinal chemistry , ionization , chromatography , ion , catalysis , computer science , operating system
RATIONALE C 25 tri‐unsaturated highly branched isoprenoid (HBI) alkenes are produced by a number of marine diatoms around the world yet are very easily oxidized during senescence to yield several isomeric allylic 9‐hydroperoxides. Elucidation of the electron ionization mass spectrometry (EIMS) fragmentation pathways of the trimethylsilyl (TMS) derivatives of the alcohols (obtained by reduction of the corresponding 9‐hydroperoxides) is essential for their characterization and quantification in natural samples. METHODS EIMS fragmentation pathways of TMS derivatives of isomeric allylic alcohols resulting from NaBH 4 reduction of photo‐ and autoxidation products of HBI alkenes were investigated. These pathways were deduced by: (i) low‐energy collision‐induced dissociation gas chromatography/tandem mass spectrometry (CID‐GC/MS/MS) and (ii) deuterium labelling. RESULTS CID‐MS/MS analyses and deuterium labelling allowed us to elucidate EIMS fragmentations of TMS derivatives of several isomeric allylic alcohols resulting from NaBH 4 reduction of HBI alkene oxidation products and to propose some specific fragment ions for differentiating individual isomers. As an application of some of the described fragmentations, these oxidized compounds in phytoplanktonic cells collected from the Antarctic were characterized and quantified in multiple reaction monitoring (MRM) mode. CONCLUSIONS EIMS fragmentations of TMS derivatives of several isomeric allylic alcohols resulting from NaBH 4 reduction of HBI alkene oxidation products are shown to be strongly dependent on the position and configuration of double bonds, allowing simple, yet robust differentiation of individual isomers in natural samples. Copyright © 2014 John Wiley & Sons, Ltd.