Analysis method of metal ion concentration in plating bath

摘要

PURPOSE:To correctly determine lead ions as well as lead and bivalent tin ions in a plating bath and also easily automate the quantification by fractionat ing plating solution from a lead alloy plating bath not containing lead or copper ions, adding iodide to have it colored, and then measuring its absorbance. CONSTITUTION:After iodide is added to plating solution to have it colored, its absorbance is measured, from which measured value lead ion concentration in a plating bath is obtained. In this case the plating bath to be analyzed is especially an electric lead or lead-allay plating bath, wherein an electric plating bath which contains aqueous lead salt substantially not containing copper ions and contains acid for dissolving the salt. Iodide to be used includes, but is not specifically limited to, KI, NaI, etc. Since there may be precipitation when iodide is added to the plating solution, complexing agent is preferably added for preventing the precipitation.