Thermal Behavior and Structure of Low-temperature Water Confined in Sephadex G15 Gel by Differential Scanning Calorimetry and X-ray Diffraction Method
Thermal Behavior and Structure of Low-temperature Water Confined in Sephadex G15 Gel by Differential Scanning Calorimetry and X-ray Diffraction Method
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DOI：
10.2116/analsci.29.353
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发表时间：
2013-03-01
影响因子：
1.6
通讯作者：
Yamaguchi, Toshio
中科院分区：
文献类型：
--
作者：
Ito, Kanae;Yoshida, Koji;Yamaguchi, Toshio
采用差示扫描量热法（DSC）和X射线衍射法（XRD）研究了Sephadex 015凝胶中水在298 - 173 K范围内的热行为和结构，水化程度h（=水质量/干凝胶质量）为0.24 - 1.38。对DSC曲线上的融冰峰进行去卷积以估计015中三种状态的水的量与h：游离水、可冻结结合水和未冻结水。未冻结水在h = 0.24的X射线径向分布函数显示，水的氢键结构在很大程度上是扭曲的，由于氢键与凝胶基质的表面羟基基团，与那些可冻结的结合水在h = 0.47和散装水相比。从承压水的结构角度考虑了凝胶色谱中溶质分离的可能机理。
The thermal behavior and structure of water confined in Sephadex 015 gel were investigated over a temperature range of 298 - 173 K at hydration levels, h (= mass of water/mass of dry 015 gel), of 0.24 - 1.38 by differential scanning calorimetry (DSC) and an X-ray diffraction (XRD) method, respectively. The ice-melting peaks on the DSC curves were deconvoluted to estimate the amounts of three states of water in 015 with h: free water, freezable bound water, and unfrozen water. The X-ray radial distribution functions of unfrozen water at h = 0.24 revealed that the hydrogen-bonded structure of water is largely distorted, due to hydrogen bonding with the surface hydroxyl groups of gel substrates, compared with those of freezable bound water at h = 0.47 and bulk water. A plausible separation mechanism of solutes in gel chromatography was considered from a structural point of view of confined water.