Influence of Different Phase-Forming Parameters on the Phase Diagram of Several PEG-Salt Aqueous Two-Phase Systems
Influence of Different Phase-Forming Parameters on the Phase Diagram of Several PEG-Salt Aqueous Two-Phase Systems
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DOI：
10.1021/je401002w
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发表时间：
2014-03-01
期刊：
影响因子：
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通讯作者：
Beutel, Sascha
中科院分区：
文献类型：
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作者：
Glyk, Anna;Scheper, Thomas;Beutel, Sascha
在23 ℃下研究了不同的聚乙二醇（PEG）+磷酸钾或柠檬酸钠的双水相体系（ATPS），该体系含有不同的PEG类型（分子量2000 g.mol（-1）~ 8000 g.mol（-1））和pH值（5 ~ 9）。此外，在23 ℃下研究了添加的盐NaCl（0重量%至8重量%）对PEG +磷酸钾/柠檬酸钠ATPS的影响。用Hu提出的经验非线性方程成功地关联了实验的双结点数据。PEG，pH值，NaCl，和盐的类型上得到的双节曲线的分子量增加的影响进行了测定，导致在一个双节曲线移向原点。因此，通过增加PEG、pH和NaCl的分子量以及由于磷酸根离子水合的吉布斯自由能，发生两相区域的膨胀。此外，得到了所有研究系统的相平衡组成，联络线长度，联络线的斜率，临界点，和有效排除体积。最后，利用Othmer-Tobias和班克罗夫特方程对实验数据进行了关联，证实了线性相关性。
Different poly(ethylene glycol) (PEG) + potassium phosphate or sodium citrate aqueous two-phase systems (ATPS) were investigated at 23 degrees C, containing different PEG types (molecular weights 2000 g.mol(-1) to 8000 g.mol(-1)) and pH values (5 to 9). Furthermore, the effect of the added salt NaCl (0 wt % to 8 wt %) on the PEG + potassium phosphate/sodium citrate ATPS was studied at 23 degrees C. The experimental binodal data were successfully correlated with the empirical nonlinear equation proposed by Hu. The effects of increasing molecular weight of PEG, pH, NaCl, and salt type on the obtained binodal curves were determined, resulting in a binodal curve shift toward the origin. Thus, an expansion of the two-phase region occurred by increasing molecular weight of the PEG, pH, and NaCl and due to the Gibbs free energy of hydration of ions of phosphate. Furthermore, the phase equilibrium compositions, tie-line lengths, slopes of tie-lines, critical points, and effective excluded volumes were obtained for all studied systems. Finally, the experimental tie-line compositions were successfully correlated by using the Othmer-Tobias and Bancroft equations, and linear dependency was confirmed.