Direct FAME synthesis for rapid total lipid analysis from fish oil and cod liver oil

A direct method for preparation of fatty acid methyl ester (FAME) via transesterification of fatty acids from fish oil and cod liver oil using methanolic sulfuric acid and chloroform as co-solvents was optimized. The synthesized FAME were subsequently analysed by gas chromatography (GC) to identify and quantify the individual fatty acid in the oils. Temperature and heating times had a significant effect on the total fatty acid (TFA) recovery. In general, temperatures of 90degreesC and 100degreesC and reaction times of 90 and 30 min, respectively, resulted in maximum recovery of TFA from the oils. TFA recoveries of more than 95% suggest that this method is suitable for quantitative analysis of individual fatty acids. In comparison, a conventional method which involved a separate extraction procedure using chloroform and methanol before FAME synthesis yielded approximately 30% lower TFA recovery from the oils. It can be concluded that the direct FAME synthesis technique is superior to the current conventional method, not only because of its simplicity, speed and economical use of solvents, but also its precision. (C) 2004 Elsevier Inc. All rights reserved.