Strategies for characterization of ganglioside inner esters. I--Fast atom bombardment mass spectrometry.

A comparison of old and new fast atom bombardment (FAB) mass spectrometric strategies for characterization of ganglioside inner esters (lactones) is presented. Data obtained for lactones of GD3 (NeuAc alpha 2----8NeuAc alpha 2----3Gal beta 1----4Glc beta 1----1Cer) using negative ion FAB mass spectrometry of underivatized materials, negative ion FAB mass spectrometry following ammonolysis, and positive ion FAB mass spectrometry following ammonolysis and permethylation are presented and discussed. The latter method uses well-known reactions to produce a novel type of ganglioside derivative, highly amenable to analysis by positive ion FAB mass spectrometry, which is introduced to simplify unambiguous location of NeuAc residues involved in ester linkages to other sugars.