SCREENING OF SEED LIPIDS FOR GAMMA-LINOLENIC ACID - CAPILLARY GAS-LIQUID-CHROMATOGRAPHIC SEPARATION OF 18/3 FATTY-ACIDS WITH DELTA-5 AND DELTA-6 DOUBLE-BONDS

Gamma-Linolenic acid (6c,9c,12c-18:3) has recently become important for dietary and pharmaceutical applications. The reported occurrence of gamma-linolenic acid in seed oils from plant families known to produce fatty acids, including 18:3 acids, with DELTA5-cis and DELTA5-trans double bonds makes it necessary to distinguish between 5c,9c,12c-, 5t,9c,12c- and 6c,9c,12c-octadecatrienoic acids by gas chromatography (GC) alone in routine screening operations. The separation of these acids using two different capillary GC systems has been investigated. The successful separation of octadecatrienoic acids with 5c, 5t and 6c double bonds is shown by way of gas chromatograms of the fatty acid methyl esters obtained from the seed oils of four different species of the family Ranunculaceae and of Xeranthemum and Pinus.