Determination of 15 Trans Fatty Acids in Edible Oil by Capillary Gas Chromatography

A method of capillary gas chromatography was proposed for simultaneous determination of 15 kinds of trans fatty acids in olive oil,sesame oil,peanut oil,and sunflower oil. The sample was dissolved in isooctane,and reacted with 2 mol·L-1 KOH-methanol solution to form fatty acid methyl esters (FAMEs),which were then separated on the highly polar Poly(bis cyanopropyl siloxane) capillary chromatographic column (SP-2560) and detected by FID. Under optimized conditions,the linear relationships between the peak area and the mass concentration of the 15 trans fatty acid methyl esters were in a certain range,with detection limits (3S/N) of 0.012% and limits of quantification (10S/N) of 0.024% . Recovery measured by standard addition method was in the range of 86.6%-109%,with RSD (n=10) in the range of 2.0%-4.2%. The method was used for the analysis of olive oil,sesame oil,peanut oil,and sunflower oil,giving results consistent with those obtained by the standard method.