Quantification of linolenic acid isomers by gas chromatography-mass spectrometry and deconvolution of overlapping chromatographic peaks

Summary

The use of a technique for deconvolution of overlapping chromatographic peaks, Gentle, has been evaluated for quantification of alpha linolenic acid isomers analysed by gas chromatography-mass spectrometry. Mixtures containing varying amounts of linolenic acid methyl ester isomers with two or three trans double bonds were analysed by two different temperature programs. Overlapping chromatographic peaks were resolved by Gentle, and the areas of the resolved peaks were compared with reference values calculated by use of internal standards. The results show that the small differences that exist between the mass spectra of the analysed isomers are sufficient to achieve deconvolution of severely overlapping peaks. The errors were larger than seen for quantification of chromatographically resolved peaks. Especially for small peaks in a peak cluster, the errors relative to the peak size were large.