摘要
本文在络合滴定分析中,采用酚酞作为指示剂,同时使用EDTA的四钠盐(Na_4Y)为络合滴定剂。用所拟方法,分别对Cu^(2+),Zn^(2+),Pb^(2+),Cd^(2+),Co^(2+),Ni^(2+),Mn^(2+)等金属离子进行了络合滴定分析。研究表明,本方法不仅终点变色敏锐,还可免除指示剂与金属离子络合而产生封闭和僵化等弊端,其测定结果与传统方法基本一致,为传统的EDTA络合滴定法增添了一种指示终点的新方法。
In this paper, with phenolphthalcin used as indicator and ethylene diaminc tctraacctic acid tetrasodium salt used as titrant, the present method is applied to the complex titration of Cu^(2+), Zn^(2+), Pb^(2+), Cd^(2+), Co^(2+), Ni^(2+), etc. The results of determination indicate that the end point of titration is sharp and that the disadvantages of closeness and stiffness caused by complexing indicator with ion are removed. The results of determination is similar to that of ordinary methods. A new method of indicating the end point of titration is established for the complex titration.
关键词
酚酞
指示剂
滴定分析
络合滴定法
complex titration
EDTA tetrasodium salt
phenolphthalein indicator
