MASS SPECTROMETRY OF METAL COORDINATED OLIGOSACCHARIDES

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The long term goal of this project includes the following: 1) determination of the absolute stereochemical configuration of oligosaccharides using metal-ligand complexation generated by fast atom bombardment (FAB) and electrospray ionization (ESI) in combination with tandem mass spectrometry (MS/MS), 2) development of analytical methodology for determination of linkage position in complex carbohydrates using ESI- MS/MS of the metal-coordinated multiply charged ions, 3) determination of gas phase dissociation mechanisms of the multiply charged species, and 4) sensitivity enhancement and structural analysis of oligosaccharide mixtures via on-line LC-MS/MS using post column addition of metal chlorides. It is anticipated that complete stereochemical analysis of oligosaccharides can be achieved using kinetic energy release measurements (KER) of the dissociation products of metal-ligand-oligosaccharide complexes. This includes the stereochemistry of all functional groups on the ring as well as differentiating the alpha and beta anomers. Additionally, ESI-MS/MS of the multiply charged metal-coordinated oligosaccharide will be investigated as a method for determining sequence and linkage position throughout the carbohydrate, as will be the on-line LC-MS/MS utilizing a triaxial probe. Each of these projects will be complemented with gas phase ion studies to determine the mechanisms of dissociation, site of metal coordination, and effects of charge localization.