Simple and rapid procedure for the determination of individual free fatty acids in serum

A microscale procedure for a rapid extraction, re-extraction and methylation of serum or plasma free fatty acids (FFAs) is described. There is no necessity to evaporate extracting solvent or heat the reaction medium to prepare corresponding methyl esters for gas chromatographic analysis. The approach comprises three consecutive steps, carried out in two reaction vials, during which the neutral lipids are removed and the free fatty acids re-extracted and subsequently methylated. Methylation succeeds upon using methyl chloroformate in combination with a non-smelling organic base within seconds. The method proved to be highly reproducible, with intraassay variation coefficients being less than 5% for the major serum fatty acids. (C) 2002 Published by Elsevier Science B.V.