Application of Fast Atom Bombardment Collision-induced Dissociation Tandem Mass Spectrometry for Structural identification of Glycerolipids Isolated From Marine Sponge

Two types of glycerolipids [monoacylglycerols (MAG) and cyclitols] were isolated by reversed phase high-performanceliquid chromatography from the MeOH extracts of a marine sponge, and analyzed by fast atom bombardment mass spectrometry(FAB-MS) in positive-ion mode. FAB mass spectra of these compounds included protonated molecules [M+H]+ and abundantsodiated molecules [M+Na]+ from a mixture of m-NBA and NaI. The structures of these compounds were elucidated by FABcollisional-induced dissociation (CID)-tandem mass spectrometry. To find diagnostic ions for their characterization, these lipidswere analyzed by collision-induced dissociation (CID) B/E-linked scan. The CID B/E-linked scan of [M+H]+ and [M+Na]+ precursorions resulted in the formation of numerous characteristic product ions via a series of dissociative processes. The product ionsformed by charge-remote fragmentation (CRF) provided important information for the characterization of the acyl chain structuresubstituted at the glycerol backbone. Some of product ions were diagnostic for the presence of a glycerol backbone and acylchain structure, respectively.