Electrochemical study and flow-injection amperometric detection of trace NO2− at CuPtCl6 chemically modified electrode

A thin film of mixed-valent CuPtCl6 is deposited on a glassy carbon electrode by continuous cyclic scanning in a solution containing 3×10−3 M CuCl2+3×10−3 M K2PtCl6+1 M KCl in the potential range from 700 to −800 mV. The cyclic voltammetry is used to study the electrochemical behaviors of nitrite on CuPtCl6/GC modified electrode and the electrode displays a good catalytic activity toward the oxidation of nitrite. The effects of the film thickness, pH, the electrode stability and precision have been evaluated. Experiments in flow-injection analysis are performed to characterize the electrode as an amperometric sensor for the detection of nitrite. The modified electrode shows a wide dynamic range, quite a low detection limit and short response time. The linear relationship between the flow-injection peak currents and the concentrations of nitrite is at a range of 1×10−7–2×10−3 M with a detection limit of 5×10−8 M.