Spectrophotometric Analysis of Cupric Ion in Plating Nickel Solution

Purity of nickel plating is influenced by codeposition of some metallic impurities in the nickelplating solution. It is very important to determine and control the content of cupric ion in the nickel bath in practice. Trace cupric ion in the nickel - plating solution can be determined directly by spectrophotometry using 2,9 - dimethyl - 4,7 - diphenyl - 1,10 -phenan- throline (bathocupronic) as color reagent at 475nm in pH = 5 buffer solution after reducing cupric ion to cuprous ion by hy-droxylamine hydrochloride. The results show that the method is rapid, simple and suitable for the application in site for little interfere of other common compositions in the nickel plating solution.