Characterization of Sodiated Lipids by Electrospray Ionization‐Quadrupole Ion Trap Tandem Mass Spectrometry

Abstract

AbstractCollisionally activated dissociation (CAD) of glycerophosphoglycerol, glycerophosphocholine, glycerophosphoethanolamine, and glycerophosphoserine species was examined using quadrupole ion trap mass spectrometry (QITMS). Since the spectral patterns obtained by QITMS may differ from those obtained using sector or quadrupole mass spectrometry, methods employed in the structure analysis of phospholipids on a sector or quadrupole mass spectrometer are not necessarily useful on an ion trap mass spectrometer. CAD (or MS/MS) of sodiated phospholipids was proposed to structurally analyze phospholipids. The CAD spectra of such ions obtained by QITMS revealed informative ions. Product ions that corresponded to the loss of polar heads identified the lipid classes. Product ions formed by the loss of fatty acyl substituents from sn‐1 and sn‐2 positions were also observed. A preferential loss of the sn‐1 fatty acyl group over the loss of the sn‐2 fatty acyl group was observed among the phospholipid standards examined. This facilitated the determination of the identities and positions of fatty acyl substituents.