Positive ion fast atom bombardment mass spectrometric analysis of the molecular species of glycerophosphatidylserine.

The structure of 1,2-dipalmitoyl-sn-glycero-3-phosphoserine was analyzed by positive ion fast atom bombardment mass spectrometry and collisional activation mass-analyzed ion kinetic energy spectroscopy. The molecular weight, the polar-head group, and the fatty acid composition of this species were identified by the appearance of protonated and solvated protonated species ions, diglyceride and monoglyceride fragment ions. After purification of glycerophosphatidylserine from bovine brain and rat kidney by normal phase high-performance liquid chromatography, molecular species were identified by either positive or negative ion fast atom bombardment mass spectrometry. The study suggests that negative ion fast atom bombardment ionization is a more powerful tool for the identification of the molecular species of glycerophosphatidylserine from biological samples. Positive ion fast atom bombardment represents a useful alternative for analysis of major molecular species in natural glycerophosphatidylserine.