CHARACTERIZATION OF BACTERIAL PHOSPHOLIPIDS BY ELECTROSPRAY-IONIZATION TANDEM MASS-SPECTROMETRY

A negative ion electrospray ionization tandem mass spectrometric techn ique was developed for the analysis of glycerophospholipids. Examinati on of the product ion mass spectrum of the deprotonated molecular ion provided sufficient information to identify both the class of glycerop hospholipid and the molecular weights of the two fatty acid moieties. This technique was applied to the profiling of glycerophospholipids pr esent in the chloroform/methanol extracts of four different bacterial species. The principal bacterial phospholipids detected by this techni que were phosphatidylglycerols and diphosphatidylglycerols, accompanie d by small amounts of phosphatidylethanolamines for two of the bacteri al species examined. The fatty acid composition of the phosphatidylgly cerols for each bacteria was determined by tandem mass spectrometry an d presented graphically. Differences in the fatty acid composition for each bacterial species were readily apparent from a visual examinatio n of the data sets.