Studies on trimethylsilyl derivatives of 1-alk-1-enyl-2-acyl glycerols by gas-liquid chromatography mass spectrometry

Trimethylsilyl derivatives of 1-hexadec-1-enyl-2-decanoyl and -2-octadecenoylglycerols and 1-octadec-1-enyl-2-decanoyl and -2-octadecenoylglycerols were subjected to analysis by a gas chromatograph mass spectrometer system. The characteristic ions are as follows: (1) ions at [M-15]+ and [M-90]+- are observed, 2 or 16 mass units less than those of the corresponding 1-alkyl-2-acyl or 1,2-diacyl derivatives; (2) the base peak is m/e 129; (3) the ion at [M-R1CH=CHO]+ or [R2COO+130]+ is present in high abundance; (4) ions at m/e 311 and 339, characteristic of trimethylsilyl derivatives of 1-hexadec-1-enyl and 1-octadec-1-enylglycerols, are due to [R1CH-CHO-1)+73]+, also confirmed from studies on the perdeuteriotrimethylsilyl derivatives; (5) several ions based on one acyl group, [R2CO]+, [R2CO+74]+ and [R2COO+74]+ are also observed.