A Simple Coulometric Method for Determining Cu[II] and Cu[I] Contents in Various Solid Samples

Abstract

Determination of copper individual oxidation states (Cu[II] and Cu[I] in various solid samples is a rather difficult problem. Results are here presented to demonstrate that constant current coulametric techniques are useful to realize these determinations with good analytical characteristics. The analytical equivalence points obtained are based on the reversible electron transfer mechanisms: Cu[II] + 3 HC1 + 2 e CuCl²⁻ ₃ + 2H⁺ and : CuCl²⁻ ₃ +e = Cu(O) + 3 Cl⁻, respectively, after quantitative dissolution in aqueous HC1 6 M. Cyclic voltammetric measurements with a carbon paste electrode are made to characterize the electron transfers involved and to investigate the analytical utility of the technique in various media. Analytical determinations are given, e.g., in the analysis of the CuO/Cu₂ O content of various samples.

Key Words:

• coulometry copper valences determination copper oxides mixture analysis