SOYBEAN OIL TRIACYLGLYCEROL ANALYSIS BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY COUPLED WITH ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRY

Soybean oil triacylglycerols from genetically modified soybean lines w ere conclusively identified by reversed-phase high-performance liquid chromatography coupled with mass spectrometry with atmospheric pressur e chemical ionization. Atmospheric pressure chemical ionization is a s oft ionization technique which gives simple spectra for triacylglycero ls. Spectral identification of the triacylglycerols was based on the m olecular [M + 1](+) ion and the 1(2)-, 2(3)- and 1(3)-diacylglycerol f ragments. Triacylglycerols identified in high-stearic and high-palmiti c soybean varieties were quantitated by reversed-phase high-performanc e liquid chromatography with flame-ionization detection. There was exc ellent agreement between the fatty acid composition calculated from th e triacylglycerol composition and the fatty acid composition obtained by gas chromatography of the transmethylated oils. The oils of the mod ified soybean varieties, compared to typical soybean oil, contained in creased content of triacylglycerols known to be more oxidatively stabl e, such as linoleoyloleoylstearoyl, linoleoylpalmitoylstearoyl, and li noleoyldipalmitoyl glycerols, and less triacylglycerols like trilinole oylglycerol, known to decrease oxidative stability. This study showed that the atmospheric pressure chemical ionization technique is suitabl e for mass spectral identification of neutral molecules, such as triac ylglycerols, which do not contain a chargeable functional group.