Abstract
Nitrite (NO(2)(-)) 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 NO(2)(-) in drinking water. We present a novel, low-cost, and easy-to-fabricate amperometric sensor designed for detecting low concentrations of NO(2)(-) in drinking water. The fabrication technique involves the electrodeposition of manganese and copper oxides onto a carbon working electrode. CuO and MnO(2) act synergistically as efficient catalysts for the electrooxidation of nitrite to nitrate (NO(3)(-)) thanks to their complementary redox properties. The resulting sensor exhibits high catalytic activity toward the electrooxidation of NO(2)(-), with a sensitivity of 10.83 μA/µM, a limit of detection (LOD) of 0.071 µM, and a good linear dynamic concentration range (0.2-60 µM). The sensor's performance was evaluated against potential interfering analytes (NO(3)(-), Cl(-), NH(4)(+), and NH(2)Cl), all of which showed negligible interference. Reproducibility (maximum standard deviation 2.91%) and repeatability (usable up to three times) were also evaluated.