Premium
The use of nicotinates and sulfoquinovosyl monoacylglycerols in the analysis of monounsaturated n‐3 fatty acids by mass spectrometry
Author(s) -
Keusgen Michael,
Curtis Jonathan M.,
Ayer Stephen W.
Publication year - 1996
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02522625
Subject(s) - chemistry , double bond , mass spectrometry , moiety , acyl group , chromatography , fragmentation (computing) , stereochemistry , organic chemistry , alkyl , computer science , operating system
Fatty acyl groups (16∶1 and 16∶0) liberated from purified sulfoquinovosyl diacylglycerols produced by the unicellular marine microalga, Heterosigma carterae (formerly H. akashiwo ), were converted to either the corresponding alcohols or methyl esters. Nicotinate derivatives of the alcohols were examined by combined gas chromatography/mass spectrometry, and the methyl esters were examined by nuclear magnetic resonance (NMR) spectroscopy after separation by high‐performance liquid chromatography. Three different hexadecenoyl fatty acyl groups were identified, one of which was cis 13‐hexadecenoyl (16∶1n−3). Both the configuration and the n−3 position of the double bond in the cis 13‐hexadecenoyl moiety were unequivocally established by NMR analysis of the corresponding methyl ester. The nicotinate derived from the alcohol of the 16∶1n−3 fatty acyl moiety gave a characteristic fragmentation series in the electron impact msss spectrum which, by careful interpretation, was consistent with, but not unambiguous for, the assigned location of the double bond. Tandem mass spectrometry experiments on a sulfoquinovosyl monoacylglycerol containing the cis 13‐hexadecenoyl group in the sn ‐2 position, using negative‐ion liquid secondary ion mass spectrometry, also gave a fragmentation pattern which was consistent with the positional assignment of the double bond.