Potentiometric Detection for Chloride in Copper Sulfate Pentahydrate Recycled from Printed Circuit Board

The determination of chloride in copper sulfate pentahydrate recycled from printed circuit board was carried out by precipitation of SO₄^2- with barium nitrate, followed by leaching and lavation, and chloride in the filtrate could be quantitatively detected by potentiometric titration method using a standard solution of silver nitrate. End volume was estimated by plotting of d²E/dV² versus addition volumes of silver nitrate. It was easily read by Excel software that the stoichiometric point was at the intersection between the curve and X-axis. The results suggested that tested results by the standard addition method gave a value of relative deviation of ≤ 4.0% (n=5) while the values of relative standard deviation (s/n=5) for three unknown samples were lower than 3.0%. Therefore, the method was proposed for the determination of chloride in copper sulfate pentahydrate recycled from printed circuit board.