REVERSED-PHASE LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY OF THE UNCOMMON TRIACYLGLYCEROL STRUCTURES GENERATED BY RANDOMIZATION OF BUTTEROIL

The test triacylglycerols were prepared by randomization of natural bu tterfat followed by silver ion TLC segregation of the saturates, monoe nes and dienes. The molecular species were identified by on-line posit ive chemical ionization mass spectrometry. Within a series of isologou s triacylglycerols, those containing the shortest fatty acid chain wer e eluted last from a reversed-phase column (XX10 > XX8 > XX6 > XX4, wh ere X = long-chain acid), although common experience would have predic ted that the shorter and more polar species would be eluted first. A c omparable order of elution was obtained for isologous triacylglycerols containing two short- and one long-chain (X88 > X86 > X66 > X84 > X64 > X44) or three short-chain fatty acids per molecule, when compared t o triacylglycerols containing medium or long-chain fatty acids in comb ination with short-chain acids. Since this resolution is similar to th at achieved on adsorption chromatography, it is suggested that the C-1 8 reversed-phase column possesses residual adsorptive activity. No dis cernible separation was seen among the corresponding positional or rev erse isomers of short-chain triacylglycerols with the present reversed -phase system.