Mass spectrometry, a powerful tool for lipid research

Fast-heating mass spectrometry of phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, and sphingomyelin

A fast-heating probe and chemical ionization have been used to obtain mass spectra of the synthetic glycerophospholipids 1,2-diacyl-sn-glycero-3-phosphocholine, 1,2-diacyl-sn-glycero-3-phosphoethanolamine, and 1-monoacyl-2-lyso-sn-glycero-3-phosphocholine. The phospholipids investigated gave quasimolecular peaks and fragment ions, with preferential cleavage of the C-O bond (beta position to the phosphorus atom) and loss of phosphoethanolamine or phosphocholine. This technique makes possible the analysis of mixtures of intact phosphatidylethanolamine, phosphatidylcholine, 2-lysophosphatidylcholine, and sphingomyelin isolated from natural sources such as egg yolk or brain. Only minor and inexpensive modifications of a standard mass spectrometer are required.

Quantitative analysis of disaturated lecithins in human plasma by ammonia chemical ionization mass spectrometry

Three physiologically important disaturated lecithins have been analyzed quantitatively as the acetate derivatives using a solids inlet probe and ammonia chemical ionization. Concentration independent response factors have been determined over a tenfold range that brackets human plasma levels. The results obtained serve as an independent corroboration of gas chromatographic analyses.