GAS-CHROMATOGRAPHY MASS-SPECTROMETRY METHODS FOR STRUCTURAL-ANALYSIS OF FATTY-ACIDS

Procedures for structural analysis of fatty acids are reviewed. The em phasis is on methods that involve gas chromatography-mass spectrometry and, in particular, the use of picolinyl ester and dimethyloxazoline derivatives. These should be considered as complementing each other, n ot simply as alternatives. However, additional derivatization procedur es can be of value, including hydrogenation and deuteration, and prepa ration of dimethyl disulfide and 4-methyl-1,2,4-triazoline-3,5-dione a dducts. Sometimes complex mixtures must be separated into simpler frac tions prior to analysis by gas chromatography-mass spectrometry. Silve r ion and reversed-phase highperformance liquid chromatography are the n of special value. In particular, a novel application of the latter t echnique, involving a base-deactivated stationary phase and acetonitri le as mobile phase, is described that is suited to the separation of f atty acids in the form of picolinyl ester and dimethyloxazoline deriva tives, as well as methyl esters.