用多乙烯多胺掩蔽镍测定酸铜镀液中锌杂质的方法

Method for determination of zinc impurity in acid copper electroplating bath after masking nickel ions by polyethylene polyamine

以硫脲掩蔽酸铜镀液中的二价铜离子,以多乙烯多胺掩蔽可能残留的二价铜离子以及镍杂质,以抗坏血酸和氟化钠分别掩蔽铁杂质和铝杂质,加醋酸钠与镀液中的硫酸反应形成醋酸-醋酸钠缓冲体系,使试液的p H为5.2～5.5。然后以二甲酚橙作指示剂,用EDTA标准溶液滴定锌离子。测定结果的相对平均偏差为0.35%,回收率为99.0%。

The copper(II)ions in an acid copper electroplating bath are masked by thiourea.The residual copper(II)ions and nickel impurities are masked by polyethylene polyamine.The iron and aluminum impurities are masked by ascorbic acid and sodium fluoride,respectively.Sodium acetate is added to the test solution and react with the sulfuric acid previously in it,forming an acetic acid–sodium acetate buffer with a pH ranging from 5.2 to 5.5.Zinc ions are then titrated by EDTA(ethylenediaminetetraacetic acid)standard solution with xylenol orange as indicator.The method features a relative average deviation of 0.35%and a recovery of 99.0%.