FTIR AND LASER-RAMAN SPECTRA OF OLIGOSACCHARIDES IN WATER - CHARACTERIZATION OF THE GLYCOSIDIC BOND

Changes in conformation of oligosaccharides, and the constraints impos ed by hydrogen bonding with the solvent, were studied by means of vibr ational spectroscopy (FTIR-ATR and laser-Raman). Oligosaccharides diff ering in positions of the glycosidic bond, such as trehalose, sucrose, maltose, melibiose, lactose, maltotriose, raffinose, and stachyose, w ere investigated. FTIR spectra of oligosaccharides in aqueous solution at different concentrations allow differentiation of these molecules according to the types of glycosidic bonds present and the changes in conformation of their constituent monosaccharides. Characteristic spec tral ranges influenced by the glycosidic linkage position, overall hyd ration, and concentration of the aqueous solution were found. Tentativ e assignment of the observed IR and Raman bands was achieved. (C) 1996 Elsevier Science Ltd.