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

Abstract 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 (β 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.