Secondary ion mass spectra of neutral sphingoglycolipids.

Secondary ion mass spectra of underivatized neutral sphingoglycolipids are presented. In the spectra of mono- and di-glycosylceramide, ions (M + H)+ and (M + H-H2O)+ were observed as relatively intense quasimolecular ions, whereas in the spectra of higher glycolipids, the quasimolecular ion species were predominantly (M + Na)+. Ions due to the ceramide moiety were observed as intense peaks comparable to quasimolecular ions. Ions derived from the fragments cleaved at the glycosidic linkages were hardly detected due to their low intensities. In general, secondary ion mass spectrometry provides good stable spectra for a long time during analysis.