电位法和极谱法联合确定镉-甘胺酸络合物稳定常数

摘要

The cadmium(Ⅱ)-glycine system was studied by the two experimental techniques, ion sensitive electrode (ISE) and differential pulse polarography (DPP), and the experimental data obtained were used by a unified mathematical treatment to calculate the complex stability constants. The combination of the two techniques is of many advantages as ISE can be performed at low [LT]:[MT] ratios and significantly higher [MT], whereas DPP could be used well at large [LT]:[MT] ratios and much smaller [MT]. This makes it possible to study a metal-ligand system in a relatively broader range of experimental conditions that, in turn, provides more information about the metakligand system of interest. Applying the unified mathematical treatment to the cadmium-glycine system, two new complexes MHL and ML2(OH) as well as three complexes ML, ML2 and ML3, reported in literatures, could be modeled and all their stability constants have been refined.%应用离子敏感电极和示差脉冲极谱两种实验技术,对镉-甘胺酸络合物体系进行研究,并通过一种联合的数学处理方法,使两种实验数据可以用来设计金属络合物体系模型及计算络合物的稳定常数.在相同的实验条件下(如总的络合剂浓度和总的金属离子浓度相同),两种实验技术将会得到几乎相同的实验络合物形成曲线和理论络合物形成曲线.将联合的数学处理方法应用于镉-甘胺酸络合物体系,不但验证了文献报道的三种络合物ML、ML2和ML3的存在,还发现了两种新的络合物MHL和ML2(OH),并且优化得到了这五种络合物的稳定常数.