消除铁离子对EDTA容量法测定锌离子的干扰实验探究

Experimental Study on Eliminating the Iron Ion Interference to the Determination of Zinc Ion by EDTA Volumetric Method

在水质监测中,用EDTA容量法测定锌含量,存在水中铁离子干扰显色滴定,终点颜色不易观察,甚至无法获得滴定终点等问题。针对铁离子对EDTA滴定锌离子带来的干扰,通过对几种掩蔽剂进行滴定选择实验,提出了在采用EDTA容量法测定锌离子中,用氟化铵与抗坏血酸复配可以掩蔽铁离子的干扰,测定结果准确并稳定。

In the process of water quality monitoring,there are some problems in the determination of zinc content by EDTA volumetric method,such as the interference of iron ion in water color titration,the difficulty in observing the end point color and even the failure to obtain the end point of titration.In view of the interference of iron ion on EDTA titration of zinc ion,through the titration selection test of several masking agents,it is proposed that the interference of iron ion can be masked by the mixture of ammonium fluoride and ascorbic acid in the determination of zinc ion by EDTA volumetric method,and the determination result is accurate and stable.