UTILITY OF NICOTINOYL DERIVATIVES IN STRUCTURAL STUDIES OF MONOACYLGLYCEROLS AND DIACYLGLYCEROLS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY .1.

The 1- and 2-monoacylglycerols and 1,2- and 1,3-diacylglycerols of sat urated and unbranched fatty acids with 8, 10, 12, 14, 16 and 18 carbon atoms were synthesized and subsequently derivatized with nicotinic ac id chloride hydrochloride. The resulting nicotinoyl derivatives were e xamined by mass spectrometry in the case of pure substances and as mix tures by gas chromatography/mass spectrometry (GC/MS). From the electr on impact mass spectra, differentiation between mono- and diacylglycer ols and between the two positional isomers of monoacylglycerols and di acylglycerols is possible. The molecular masses of the partial acylgly cerols and the identities of the bonded fatty acid were also determine d. Similarly to the nicotinoyl derivatives of saturated fatty alcohols , the nicotinoyl derivatives of partial acylglycerols produce a fragme ntation pattern that reflects every methylene group of the alkyl chain s. These results offer rules for the structure elucidation of partiall y acylated acylglycerols and probably for mixed diacylglycerols by mea ns of GC/MS, which includes the detection of double bonds and methyl b ranch positions at the fatty acid alkyl chains. The molecular formulae of all the important fragments in the mass spectra of the nicotinoyl derivatives were confirmed by high-resolution mass spectrometry. Their structures and fragmentation pathways are proposed.