Determination of nitrite and nitrogen oxides by anodic voltammetry at conductive diamond electrodes

The oxidation of nitrite at boron-doped diamond (BDD) electrode was investi gated by use of anodic voltammetry. The voltammetric curves exhibit well-de fined anodic peaks, with response that is superior to that obtained with gl assy carbon electrodes. The influence of pH, nitrite concentration: and pot ential sweep rare on the electrode response was thoroughly investigated. Th e results show that the measurement of the oxidation peak current can be us ed as the basis for a simple, accurate, rapid method for the determination of NO2-. within a concentration range of 0.002-1 mM. Flow injection analysi s with amperometric detection was also examined and improved sensitivity wa s observed, with analytical useful signals being obtained at 50 nM. The pos sibility of using anodic voltammetry for the determination of nitrogen oxid es (NO and NO2 was also assessed. It is shown that BDD is a very promising electrode material for the detection of nitrogen oxides (NO,NO2) in gases a nd the determination of NO in aqueous solution. (C) 2001 The Electrochemica l Society.