A quick routine analysis has been established for quantitative determination of thirteen individual C18
trans fatty acids in both pressed and solvent extracted non-hydrogenated edible vegetable oils, using gas
chromatography-mass spectrometer (GCeMS) equipped with HP-88 capillary column following potassium
hydroxide/methanol (KOH/MeOH) methylation. Based on optimization and appraisal of the characteristics
of GCeMS, thirteen C18 trans fatty acid methyl ester (FAME) standards were separated and
verified in 23 min, validation experiments were also conducted. The correlation coefficient was R2 0.99
in the linear range of each FAME. At the low, medium and high fortification levels, recoveries fell within
90e119%. The relative standard deviations were below 9% for all 13 FAMEs. Low limits of detection (0.001
e0.002 g/100 g) and quantification (0.002e0.007 g/100 g) were readily achieved. The content of C18
trans fatty acid isomers in pressed and solvent extracted oils were analyzed using this method.