示差脉冲极谱法测定铋-邻吡啶甲酸体系的络合物稳定常数  

DETERMINATION OF STABILITY CONSTANT OF THE COMPLEX FORMED BETWEEN BISMUTH AND PYRIDINE-2-CARBOXYLIC ACID BY DIFFERENTIAL PULSE POLAROGRAPHY

作　　者：张建民[1] 鲍改玲[1] 魏爱卿[1] 

机构地区：[1]郑州大学化学系,郑州450052

出　　处：《理化检验（化学分册）》2004年第9期514-516,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：教育部留学回国人员科研启动基金资助项目

摘　　要：在5×10-5mol·L-1Bi(Ⅲ)溶液中,增加络合剂邻吡啶甲酸的浓度,用示差脉冲极谱法研究铋 邻吡啶甲酸体系。通过计算机分析程序求解体系的质量平衡方程及拟合试验络合物形成曲线,优化得到铋和邻吡啶甲酸形成的络合物BiL2+和BiL+2的稳定常数,分别为7.51±0.03和13.92±0.04。The differential pulse polarographic method was used effectively for the determination of stability constant of complexes of bismuth(Ⅲ). In this paper, the stability constant of the complex of bismuth(Ⅲ) with pyridine-2-carboxylic acid was determined by the polarographic method in a solution having the concentration of Bi(Ⅲ) ion at 5×10^(-5)mol·L^(-1), and at varying concentrations of the ligand pyridine-2-carboxylic acid, while keeping a constant pH condition. After each addition of the ligand solution, the value of the ratio of total ligand concentration [L_T] and total metal ion concentration [M_T] will increase, resulting a change of the values of peak potential (E_p) and peak current (I_p). With the help of a computer, the stalility constant of the complex was calcalated according the mass-balance equation and the fitting curve of complex formation. After optimization, the stability constants of two complexes of bismuth and pyridine-2-carboxylic acid (BiL^(2+), BL^+_2) were obtained as (lgβ) 7.51±0.03 and 1392±0.04 respectively.

关 键 词：铋-邻吡啶甲酸体系 络合物 稳定常数 示差脉冲极谱法 

分 类 号：O614.532[理学—无机化学] O657.14[理学—化学]