Electrocatalysis and determination of hydrazine compounds at glassy carbon electrodes coated with mixed‐valent ruthenium(III, II) cyanide films

Abstract Chemically modified electrodes, which were constructed by anodizing glassy carbon electrodes in a RuCl 3 /K 4 Ru(CN) 6 solution, are shown to catalyze the electrooxidation of hydrazine compounds in acidic and neutral media. The mixed‐valent ruthenium cyanide film offers improved stability and a broader operational pH range compared to previously described phthalocyanine‐catalytic surfaces. The catalytic response of hydrazine, methylhydrazine, and dimethylhydrazine is evaluated with respect to the film preparation conditions, solution pH, potential scan rate, concentration dependence, and other variables. Highly stable and sensitive flow injection measurements [with a relative standard deviation (RSD) of 1.4% ( n = 30) and a detection limit of 0.13 ng] are described. A composite film prepared by the codeposition of polyaniline offers additional advantages.