STRUCTURE DETERMINATION OF DIACYLGLYCEROLS AS THEIR NICOTINOYL DERIVATIVES BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Nicotinoyl derivatives were used for the investigation of the structur e of diacylglycerols with two different fatty acid residues by gas chr omatography-mass spectrometry (CC-MS), Their electron ionisation mass spectra reveal the structures of diacid diacylglycerols in greater det ail than the mass spectra of other diacylglycerol derivatives, The exa ct structure of the fatty acid alkyl chains, such as double bond and m ethyl branching positions, can be determined by characteristic feature s in fragmentation patterns which are induced by the pyridine nucleus. Besides, determination of fatty acid position in the glycerol backbon e of diacid 1,2-diacylglycerols is simple. Caused by the two nicotinoy l-induced fragmentation patterns reflecting each of the two fatty acid residues, the mass spectra of diacid diacylglycerol derivatives are m ore complex than those of monoacid diacylglycerol derivatives, Since s ome of the diagnostic ions occur at identical masses, structural inter pretation of the spectra may be critical in certain cases.