示波极谱滴定研究(Ⅸ)——四苯硼钠滴定钾

INVESTIGATIONS ON OSCILLOPOLAROGRAPHIC TITRATIONS(Ⅸ)-Titration of Potassium With Na-TPB

提出了一个用四苯硼钠在交流示波极谱图上的切口来指示终点的测定常量钾的容量方法。方法快速、准确,干扰很少。

In slightly acidic or alkaline solution of acetate,sodium tetraphenyl-borate(Na-TPB)gives a sharp incision on its oscillopolarogram which can be used to indicate the end point of titration Involving Na-TPB.In the determination of K,excess of standard Na-TPB solution is added to precipitate the K ions in alkaline(PH=12)solution and part of the mixture is filtered through dry filter paper and the excess TPB in the filtrate is titrated with T1(I)solution.Divalent and trivalent ions that precipitate in alkaline solution do not interfere with the determination.Pb+2 and Sn+2 ions that distort the oscillopolarogram of TPB can be masked by EDTA.The method is very simple,accurate and rapid.Thin film Hg electrode is used as a polarized electrode,and the Hg-coated Ag electrode as a depolarized electrode.