Gas chromatographic—mass spectrometric identification of the fatty acids in borage oil using the picolinyl ester derivatives

Abstract

When subjected to capillary gas chromatography, picolinyl ester derivatives of fatty acids were shown to have as good chromatographic properties as the corresponding methyl esters. By using a capillary column of medium polarity (Supelcowax 10), excellent resolution with respect to chain length, degree of unsaturation and positional isomers was obtained without any serious problems with a disturbed background due to column bleed in the mass spectrometric interpretation of diagnostic ions. These features permitted a simple one-step procedure to be carried out for the characterization of fatty acids with respect to molecular weight, number of double bonds and positional isomers. The usefulness of the technique for the identification of the fatty acids in borage seed oil ( Borago officinalis) was demonstrated. In addition to γ-linolenic acid, the most important fatty acid in borage seed oil from a commercial standpoint, a further fourteen different fatty acids could be positively identified.