A COMPARISON OF SILVER ION HPLC PLUS GC WITH FOURIER-TRANSFORM IR SPECTROSCOPY FOR THE DETERMINATION OF TRANS-DOUBLE BONDS IN UNSATURATED FATTY-ACIDS

A rapid procedure has been developed for the isolation of methyl ester s of trans-monoenoic fatty acids by silver ion high-performance liquid chromatography. The combined saturated plus trans-monoene fraction wa s collected for analysis by gas chromatography and comparison with the composition of the unfractionated sample. The trans-monoene contents of partially hydrogenated vegetable oils, determined in this way, are compared with data obtained by Fourier-transform infrared spectroscopy . Alternative methods of base-line correction are discussed. The infra red technique gave values that were a little higher than the chromatog raphic ones, presumably because the former also detected trans unsatur ation in di- and polyunsaturated fatty acids.