Studies on trimethylsilyl derivatives of 1-alkyl-2-acylglycerols by gas-liquid chromatography mass spectrometry.

Trimethylsilyl derivatives of 1-hexadecyl-2-decanoyl-, -hexadecanoyl- and -octadecenoyglycerols and 1-octadecyl-2-decanoyl-, hexadecanoyl- and -octadecenoylglycerols as well as 1,2-dihexadecanoylglycerol were analysed by a gas chromatography mass spectrometer system. The following points are characteristic of the fragmentation pattern of these 1-alkyl-2-acyl derivatives: (1) in the spectra of alkyl acyl derivatives, ions at [M -15]+ and [M - 90A1+. are 14 mass units less than those of the corresponding diacyl derivatives; (2) the base peak is m/e 130; (3) alkyl acyl derivatives show fragments due to one acyl group instead of the two acyl groups of diacyl derivatives; (4) ions at m/e 314 and 342, [R1O + 73]+., are characteristic of the trimethylsilyl derivatives of hexadecyl- and octadecylglycerols, respecitvely; (5) the ion [M -R1O]+ is present, but the complementary alkoxy ion is absent.