盐酸二甲双胍离子选择电极的研制及应用——模拟微分法确定电位滴定终点的研究

Preparation and Application of Metformin PVC Membrane Electrode——Study on Determination of Potentionmetric End Point by Simulated Derivative Method

本文研制成玻璃电极作为内导的盐酸二甲双胍PVC膜电极并作为电位滴定指示电极,在水溶液中以四苯硼钠作为沉淀剂对二甲双胍片剂进行了电位滴定分析。利用计算机对所得电位滴定曲线进行三次线性模拟,模拟所得三次方程经二阶微分法来确定滴定终点,与近似微商法对比,准确直观,结果满意。

A metformin PVC membrane electrode was preparad using glass electrode as inner reference electrode. Experimental results demonstrate that the general performance of the electrode is the same as the common liquid inner reference ones. The new simulated derivative method to determine the potentiometric end point was studied. The titration curve is simulated as the cubic equation as follows: y = ax3+bx2+cx+d. The second order derivative is d2y/dx2=6ax + 2b If d2y/dx2 = 0,then x=- b/3a is the end point. The method was applied to analyze metformin tablet samples with satisfactory results.