Catalytic oxidation of reduced nicotinamide adenine dinucleotide at a microband gold electrode modified with nickel hexacyanoferrate

Nickel hexacyauoferrate films have been deposited on the surface of a microbaud gold electrode by cyclic voltammetry. Cyclic voltammograms of the resulting nickel hexacyauoferrate films indicate the presence of a couple of redox peaks which correspond to the hexacyanoferrate(II/III) redox couple. The nickel hexacyanoferrate modified microband gold electrode shows an excellent electrocatalytic activity for oxidation of reduced nicotiuamide adeniue diuucleotide (NADH) in phosphate buffer solution (pH 7.0), with au overpotential ca. 340 mV lower than that of the bare electrode. The steady-state current increases linearly with NADH concentration in the range of 0.5-8.0 mm&. The catalytic rate constant of the modified electrode for the oxidation of NADH is determined using a rotating disk electrode. The further experimental results show that the rate constant decreases with increasing NADH concentration. The mechanism of the oxidation of NADH catalyzed by the nickel hexacyanoferrate modified gold electrode is discussed. Keyworak Catalytic methods; Microelectrodes; Electrocatalytic oxidation; NADH, Nickel hexacyanoferrate