SILVER-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ELECTROSPRAY MASS-SPECTROMETRY OF TRIACYLGLYCEROLS

Silver-phase chromatography hyphenated with on-line electrospray mass spectrometry can be applied to characterize triacylglycerols present i n vegetable oils with respect to their degree of unsaturation, the pos ition of the most unsaturated fatty acid and the carbon number (CN). T he CN information obtained with silver-phase HPLC-ESP-mass spectrometr y is complementary to the unsaturation information obtained by silver- phase HPLC-flame ionization detection. Both information is essential t o monitor or study modified vegetable oils on the presence of non-natu ral triacylglycerols. The quantitative results obtained with the metho d are in agreement with the results obtained in the silver-phase HPLC- flame ionization detection and with theoretical values calculated from the fatty acid distribution of the oil. Silver-phase HPLC-ESP-mass sp ectrometry gives direct information on fatty acid position and triacyl glycerol CN, for each of the triacylglycerols in the sample. This in c ontrast with non-aqueous reversed-phase HPLC hyphenated with on-line a tmospheric pressure chemical ionization-mass spectrometry, which requi res a more extensive data processing. The results obtained with silver -phase HPLC-ESP-mass spectrometry can be presented in a three-dimensio nal overview (relative amount, CN. fatty acid position) serving as a f ingerprint for the oil. (C) 1998 Elsevier Science B.V. All rights rese rved.