A Rayleigh light scattering study on mixing states of 2-propanol-water binary mixtures widely used as mobile phase in separation.
A Rayleigh light scattering study on mixing states of 2-propanol-water binary mixtures widely used as mobile phase in separation.
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DOI：
10.1016/s0039-9140(00)00625-1
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发表时间：
2001-03
期刊：
影响因子：
6.1
通讯作者：
Y. G. Wu;M. Tabata;T. Takamuku
中科院分区：
文献类型：
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作者：
Y. G. Wu;M. Tabata;T. Takamuku
用普通荧光光度计在25°C下测量了异丙醇-水二元混合物在546 nm处的瑞利光散射。由散射强度计算了异丙醇摩尔分数为0.0≤ x ~ 2 pr ≤0.4（0-75%（v/v））范围内混合物的均方浓度涨落和Kirkwood-Buff参数。基于这些参数，已经得出结论，在x2 pr <0.05（15%（v/v））下，2-丙醇被水分子良好地溶剂化，并且在混合物中形成由一个2-丙醇分子和20-30个水分子组成的水合物。然而，在0.05≤ x2 pr ≤0.3（15-65%（v/v））时，在混合物中形成主要由2-丙醇分子组成的大簇，并且这些簇在x2 pr ≥0.4时进一步还原成小的2-丙醇聚集体。使用2-丙醇作为有机改性剂和其对CE和RPLC分离的影响也讨论了在移动的相的微观不均匀性。
Rayleigh light scatterings of 2-propanol–water binary mixtures at 546 nm have been measured by using a conventional fluorophotometer at 25°C. Mean square concentration fluctuations and Kirkwood–Buff parameters of the mixtures in a range of 2-propanol mole fraction of 0.0≤x2pr≤0.4 (0–75% (v/v)) have been calculated from the scattering intensities. On the basis of these parameters, it has been concluded that at x2pr<0.05 (15% (v/v)) 2-propanol is well solvated by water molecules, and hydrates consisting of one 2-propanol molecule and 20–30 water molecules are formed in the mixtures. However, at 0.05≤x2pr≤0.3 (15–65% (v/v)) large clusters mainly composed of 2-propanol molecules are formed in the mixtures, and these clusters are further reduced into small 2-propanol aggregates at x2pr≥0.4. The usage of 2-propanol as organic modifier and its effects on CE and RPLC separations are also discussed in terms of microheterogeneity in the mobile phase.