Liquid-liquid equilibrium data were obtained for aqueous two-phase systems (ATPS) formed by polyethylene glycol (4000 or 6000 g mol⁻¹) + potassium phosphate (K₂HPO₄/H₃PO₄ or K₂HPO₄) + water. The effect of adding (0.05%) [w/w] of the dioctyl sulfosuccinate sodium (AOT) to the polymeric solution was studied. ATPS were determined using the turbidimetric method, at two pH values (7.0 and 9.3) and 298.15 K. Three tie-lines (TL) were determined using the lever rule. The effect of the variables pH, polymer molar mass and presence of the surfactant on binodal curves and TL were evaluated. In order to study the capacity of phase formation and the salting-out ability of the system-forming components, the salting-out effect and effective volume (EEV) of exclusion were determined. An increase in the biphasic region at the highest values of pH and molar mass of PEG was verified. Such results were correlated with the values of the parameters coefficient salting-out (k) and EEV. The increase in the system global composition caused an increase on the tie-lines length, varying in the range of (0.243–0.415). The different conditions determined had little effect on the tie-lines slope (STL). It was found that the presence of AOT in these ATPS caused a decrease in the EEV values of the systems (4285.916 − 6987.256).

获得了由聚乙二醇（4000或6000 g mol ^-1）+磷酸钾（K ₂ HPO ₄ / H ₃ PO ₄或K ₂ HPO ₄形成的水两相系统（ATPS）的液-液平衡数据）+水。研究了向聚合物溶液中添加（0.05％）[w / w]的磺基琥珀酸二辛酯钠（AOT）的效果。使用比浊法在两个pH值（7.0和9.3）和298.15 K下确定ATPS。使用杠杆法则确定三个联系线（TL）。评估了变量pH，聚合物摩尔质量和表面活性剂的存在对双曲线和TL的影响。为了研究相形成的能力和系统形成组分的盐析能力，确定了盐析作用和有效体积（EEV）。证实了在pH和PEG的摩尔质量最高时双相区的增加。这样的结果与参数系数盐析值（k）和EEV。系统整体组成的增加导致联络线长度增加，范围在（0.243–0.415）之间。确定的不同条件对联络线斜率（STL）的影响很小。发现这些ATPS中存在AOT导致系统的EEV值降低（4285.916-6987.256）。