氨基酸溶解平衡的热力学研究

Thermodynamic study on solubilitiesof amino acids

对甘氨酸、Ｌ－丙氨酸在不同温度下溶解度随ｐＨ值变化的关系进行了实验测定。结合化学平衡理论，建立了计算氨基酸溶解度的热力学模型。对９种氨基酸和５种肽的活度系数实验值进行了回归，得到了氨基酸与水的ＵＮＩＱＵＡＣ相互作用参数。对１１种氨基酸的溶解度随温度变化的关系进行了计算。通过回归０～７０℃的溶解度实验数据得到了溶解平衡常数方程的参数。利用上述参数对７０～１００℃的溶解度进行了预测。回归及预测结果均与实验值符合。

The solubilities of glycine and Lalanine were measured at different pH values and temperatures. A thermodynamic framework was established to calculate the solubilities of amino acids with the chemical equilibria taken into account simultaneously. The experimental activity coefficients of nine amino acids and five peptides were correlated and the UNIQUAC interaction parameters of amino acid (peptide)water were obtained. The solubilities of eleven amino acids at different temperatures in pure water were calculated. The parameters of the solubility equation were obtained by correlating the solubilities of amino acids ranged from 0 to 70℃. Then, the solubilities ranged from 70 to 100℃ were predicted. The correlated and predicted results are coincided well with the experimental data.