Multicomponent analysis of sodium cuprate, NaCuO2−x, having a high Cu(III) content

Sodium cuprate with a high Cu(III) content was synthesized and characterized with emphasis on the determination of Cu(III). Results of multicomponent analysis, carried out in two independent laboratories employing several different methods, are compared and discussed. For Cu(III) determination, improved or newly developed iodometric and voltammetric methods were used. A good agreement on the high Cu(III) content (97–98% of total copper) was found. Virtually no peroxidic oxygen was found employing a specific photometric procedure. Other components, sodium and total copper, were determined by means of usual methods: inductively coupled plasma atomic emission spectroscopy (ICP-AES), atomic absorption spectroscopy (AAS), flame emission spectroscopy (FES) and ion selective electrode (ISE)/potentiometry. This preliminary interlaboratory characterization study showed that sodium cuprate, synthesized by the applied method, can be considered as a potential Cu(III) standard reference material.