Negativeion electrospray mass spectrometry was used to determine directly both glycosidic linkage position and anomeric configuration in the complete glucopyranosyl disaccharide series without the need for derivatization or tandem mass analysis. A series of empirical criteria were developed which first differentiate between the linkage positions and then the anomeric configurations using selected diagnostic peaks and their relative intensities. The use of standard mass spectral library searching methods for structural analysis was also investigated.

Molecular orbital calculations were used to investigate the fragmentation of deprotonated glucopyranosyl disaccharides. Based on data from collisional activation and isotopic labeling experiments, fragmentation mechanisms are proposed, with calculated transition states being used to study the energetics of fragmentation. The calculations suggest that deprotonation at the C(2) hydroxyl of the non‐reducing ring, following ring opening, may be important for disaccharide fragmentation. It is also shown that the stereochemistry at the 2‐position of the non‐reducing ring may have a significant effect on disaccharide fragmentation, particularly with regard to determination of the anomeric configuration. Copyright © 1999 John Wiley & Sons, Ltd.

AM1 and ab initio calculations were performed for molecular glucopyranose and its alkoxy anions. Minimum energy conformers were found for both the α‐ and β‐anomers of molecular glucose and each of the corresponding deprotonated species. Cooperative hydrogen bonding towards the charge site was observed for the anions, which is similar to the cooperative counterclockwise hydrogen bonding that occurs with the neutral molecular species. The anomeric hydroxyl was found to be the most acidic hydroxyl group for α‐glucopyranose, while the C(4) hydroxyl was the most acidic site for the β‐anomer. In all cases the primary hydroxyl at C(6) was the least acidic site. Copyright © 1999 John Wiley & Sons, Ltd.

AM1 and ab initio calculations were performed for molecular glucopyranose and its alkoxy anions. Minimum energy conformers were found for both the a-and b-anomers of molecular glucose and each of the corresponding deprotonated species. Cooperative hydrogen bonding towards the charge site was observed for the anions, which is similar to the cooperative counterclockwise hydrogen bonding that occurs with the neutral molecular species. The anomeric hydroxyl was found to be the most acidic hydroxyl group for a-glucopyranose, while the C(4) hydroxyl was the most acidic site for the b-anomer. In all cases the primary hydroxyl at C(6) was the least acidic site.