Measuring method null of chelate agent concentration and hydroxide ion concentration and reducing agent concentration in chemical copper plated

摘要

PURPOSE:To enable execution of simple and accurate measurement by a method wherein a sample solution of which titration by a water solution of the salt of heavy metal ions is ended is given the sulfite of an alkali metal and then titrated by the water solution of the salt of the heavy metal ions. CONSTITUTION:When a sample solution is titrated by a water solution of the salt of heavy metal ions, a chelating agent and hydroxide ions react sequentially with the heavy metal ions. The end point of the reaction of the chelating agent is a point A whereat pH begins to decrease sharply. The end point of the reaction of the hydroxide ions is an inflection point B whereat the sharp decrease of pH becomes gentle. The concentration of the chelating agent and that of the hydroxide ions are determined from the amounts of titration of these two end points of reaction. When the sulfite of an alkali metal is given to this sample solution, subsequently, a reducing agent which does not react in titration reacts with the sulfite and makes the hydroxide ions produced. By conducting second titration by the water solution of the salt of the heavy metal ions and by determining the quantity of hydroxide ions produced afresh, accordingly, the concentration of the reducing agent is determined.