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利用Anton Paar DMA55精密数字密度计测定了288.15,298.15和308.15K甘氨酰甘氨酸在蔗糖-水混合溶剂中的密度,计算了甘氨酰甘氨酸的表观摩尔体积VΦ和极限偏摩尔体积VΦο,得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积ΔtrsVΦο和理论水化数Nh.根据共球交盖模型,讨论了迁移偏摩尔体积和水化数的变化规律.结果表明,甘氨酰甘氨酸带电中心与蔗糖之间的结构相互作用对其迁移体积有正贡献,且占主导地位.甘氨酰甘氨酸的迁移偏摩尔体积为正值,且随着蔗糖浓度的增大而增大;理论水化数随温度升高、蔗糖浓度的增大而减小;温度升高,极限偏摩尔体积增大,迁移偏摩尔体积变化很小.
The densities of 288.15, 298.15 and 308.15K glycylglycine in sucrose-water mixed solvents were determined by Anton Paar DMA55 precision digital densitometer, and the apparent molar volume VΦ and the limit partial molar volume VΦο of glycylglycine were calculated. The migration partial molar volume ΔtrsVΦo and the theoretical hydration number Nh from the pure water solvent to the mixed solvent are discussed.The changing regularity of migration partial molar volume and hydration number are discussed according to the common ball cover model.The results show that the glycine The structural interaction between the acylglycine charged center and sucrose has a positive contribution to the migration volume, and predominates. The partial molar volume of glycylglycine migration is positive and increases with increasing sucrose concentration. The theoretical hydration number decreases with the increase of temperature and the increase of sucrose concentration. When the temperature rises, the limit partial molar volume increases and the change of partial molar volume of migration is small.