Glycosphingolipids. Application of Fab Mass Spectrometry and High Resolution Proton Nmr

The potential of fast atom bombardment (FAB) mass spectrometry and of high resolution proton NMR spectroscopy, in the structure elucidation of complex glycosphingolipids (GSL), was assessed with the aid of unmodified, peracetylated and permethylated derivatives. The results of negative ion FAB MS on native GSL and of positive FAB MS on their permethylated derivatives proved to be highly complementary to those obtained by the use of different NMR techniques. Examples of FAB spectra, of spin-decoupled spectra, of NOE (Nuclear Overhauser effect) difference spectra, of 3-resolved two-dimensional spectroscopy, as well as of the COSY (chemical shift correlated) or the SECSY (spin-echo correlated) variant of the two-dimensional spectroscopy, measured at 360 or 500 MHz, demonstrate that with a minimal amount of substance complete informatkn can be gathered on the molecular weight, ceramide moiety, the type and number of sugar constituents, their anomeric configuration, sequence, sites of linkages and branching patterns.