Catalytic adsorptive stripping voltammetric determination of cobalt as an α‐benzil dioxime complex in the presence of an extremely large excess of zinc

There is considerable interest in determining trace amounts of cobalt in highly concentrated zinc solutions. Existing commonly used voltammetric methods such as those based on formation of dimethlyglyoxime complexes and adsorptive stripping voltammetry, while very sensitive for the determination of cobalt, do not always provide the necessary discrimination against the zinc (and nickel) processes. In the present work a recently described method, based on the formation and adsorption of a cobalt–α‐benzil dioxime complex and catalyzed by nitrite, has been optimized so at a 106 to 107 M concentration excess of zinc can be tolerated. Since the method is also relatively insensitive to nickel, it can be applied to highly purified zinc electrolytes.