中文摘要：

目的应用Uniquac模型计算聚山梨酯20溶液的冰点。方法根据Uniquac模型，由聚山梨酯20溶液中溶质的质量分数计算溶剂水的活度，进而计算出溶液的冰点，并将计算结果与步冷曲线冰点测定法、空气湿度冰点测定法的测量值进行比较。结果由Uniquac模型计算得到的冰点与用空气湿度冰点测定法得到的冰点值一致，与步冷曲线冰点测定法得到的冰点在低浓度下一致而在高浓度下相差较大。结论聚山梨酯20溶液的冰点值可以通过Uniquac模型直接计算得到。

英文摘要：

OBJECTIVE To calculate the freezing point of polysorbate 20 solution by Uniquac model. METHODS According to Uniquac model, the water activity of polysorbate 20 solution was calculated by mass fraction of solute. Then the freezing point of solution was calculated. The calculated results were compared with those obtained by cooling curve cryoscopy and air humidity cryoscopy. RESULTS The Uniquac model calculations were comparable to the measurements of air humidity cryoscopy at the measuring range and cooling curve cryoscopy at low concentration, while they are different with the measurements of the cooling curve cryoscopy at high concentration. CONCLUSION The freezing point of polysorbate 20 solutions can be calculated according to Uniquac model.