Abstract
FTIR spectra are obtained for several different states of trehalose including dihydrate crystal, anhydrous form II, anhydrate crystal, dried melt, amorphous solid and aqueous solution. From the observation of the symmetric and antisymmetric stretch vibrations of the glycosidic linkage, it is found that this sugar takes at least three types of backbone conformation. The Ca symmetry structure of trehalose seems to have a feature that the sugar easily catches up water molecules. The sugar's conformation in anhydrous form II is shown to be 2. Next, the hygroscopic abilities of the anhydrate, form II and the amorphous solid are compared based on their IR spectra. Interestingly, form II alone is converted to the original dihydrate in a week under mild environmental conditions: relative humidity of 40% and room temperature. These results suggest the possibility that form II plays a role in avoiding the devitrification of the sugar glass. Finally we discuss the role of form II in preserving freeze-dried biomaterial.
