Fatty acid methyl esters GC/FID analysis using Ichihara-Fukubayashi modyfied method

The method for preparing fatty acid methyl esters (FAMEs) from lipids for gas-liquid chromatography, developed by K. Ichihara and Y. Fukubayashi, was optimized as a result of research on the influence of mild (45 °C, for 14 h) and fast (100 °C, for 1 h) methanolysis-methylation conditions on the FAMEs yield. Based on the minor impact on the final products and the good FAMEs yields, the optimized mild methanolysis/methylation method was applied to eight vegetable oil samples and two types of fish oil dietary supplements. The FAMEs compositions were analyzed by gas chromatography with flame ionization detector (GC/FID). On the recorded chromatograms, 16 types of fatty acids with majority content were identified and their mass fractions were calculated. The modified Ichihara-Fukubayashi method allowed the conversion of ester-bound fatty acids and free acids to FAMEs in a single step. The accuracy, accessibility and convenience of the method, the use of low concentrations of samples and reagents were noted.