Stepwise determination of metallic copper, cuprous oxide and cupric oxide using redox-titrimetric methods

Each component of a mixture containing Cu2O, CuO and metallic copper could be determined sequentially using three different redox-titrimetric methods. First, the sample was dissolved in a solution of acetonitrile and hydrochloric acid (1/l) and filtered. The filtrate was titrated by permanganate solution to obtain Cu2O. Next, the sample was dissolved in an aqueous solution of ferric chloride and the Fe2+ formed was titrated by permanganate solution to obtain the amount of Cu2O and metallic copper from which the amount of metallic copper was calculated. Finally the total amount of copper was obtained by dissolving the sample in nitric acid and doing an iodometric titration, and the amount of CuO was calulated.