Quantification of lysophosphatidylethanolamine in the nanomole range

A microanalytical procedure for the determination of trace amounts of lysophosphatidylethanolamine and other amine-containing lipids is described. The technique involves reaction of lipid extracts with fluorescamine to give fluorescent derivatives of lipids containing a free amino group, separation of the products by thin-layer chromatography, and quantification by fluorescence spectroscopy after elution from the adsorbent. Amounts of 100 pmol are easily determined, even in the presence of large amounts of other phospholipids, and 30-40 samples can be analyzed per day. Use of the procedure is illustrated with rat liver mitochondria undergoing a phospholipase A2-dependent increase in inner membrane permeability due to treatment with Ca2+ plus N-ethylmaleimide.