Direct transesterification of lipids in mammalian tissue for fatty acid analysis via dehydration with 2,2'-dimethoxypropane.

A method is described for the transesterification of lipids of mammalian tissues for fatty acid analysis by gas-liquid chromatography (GLC) that eliminates the extraction step of conventional procedures. The method involves the direct reaction of anhydrous HCl-methanol with the lipids in approximately 10 mg of tissue or 0.1 ml of serum after removal of water by reacting it with 2,2'-dimethoxypropane (DMP). Acetone and methanol produced from water in the sample, as well as the excess DMP, are evaporated prior to transesterification in order to eliminate the formation of artifacts from the solvents. The method was demonstrated with rat serum and brain tissue.