Electrocatalytical Nitrite Oxidation via Manganese and Copper Oxides on Carbon Screen-Printed Electrode

Nitrite (NO2-) has long been recognized as a contaminant of concern due to its detrimental effects on both human health and the environment. As a result, there is a continuing need to develop sensitive, real-time, low-cost, and portable systems for the accurate detection of trace levels of NO2- in drinking water. We present a novel, low-cost, and easy-to-fabricate amperometric sensor designed for detecting low concentrations of NO2- in drinking water. The fabrication technique involves the electrodeposition of manganese and copper oxides onto a carbon working electrode. CuO and MnO2 act synergistically as efficient catalysts for the electrooxidation of nitrite to nitrate (NO3-) thanks to their complementary redox properties. The resulting sensor exhibits high catalytic activity toward the electrooxidation of NO2-, with a sensitivity of 10.83 mu A/mu M, a limit of detection (LOD) of 0.071 mu M, and a good linear dynamic concentration range (0.2-60 mu M). The sensor's performance was evaluated against potential interfering analytes (NO3-, Cl-, NH4+, and NH2Cl), all of which showed negligible interference. Reproducibility (maximum standard deviation 2.91%) and repeatability (usable up to three times) were also evaluated.