QUANTITATIVE-ANALYSIS OF BIOLOGICAL MEMBRANE-LIPIDS AT THE LOW PICOMOLE LEVEL BY NANO-ELECTROSPRAY IONIZATION TANDEM MASS-SPECTROMETRY

Nano-electrospray tandem mass spectrometry allows qualitative and quan titative analysis of complex membrane lipid mixtures at the subpicomol e level, We have exploited this technique to selectively detect indivi dual classes of phospholipids from unprocessed total cellular lipid ex tracts by either precursor ion or neutral loss scanning, This way phos phatidylcholine, sphingomyelin, phosphatidylinositol and -phosphates, phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, ph osphatidic acid, and their plasmalogen analogues can be detected. The optimized ionization and fragmentation conditions described together w ith the principle of internal standardization by nonnatural analogues allow the rapid and quantitative determination of membrane lipid compo sitions down to sample amounts of 1000 cells.