Interferent-Free Electrochemical Detection of Nitrate in Water Using Copper–Cobalt-Based Sensor

Nitrate contamination in water is a significant global concern, prompting regulatory bodies such as the European Union to set a maximum permissible limit of 44 mg/L in drinking water. However, conventional laboratory-based detection methods are time-consuming and require specialized expertise, while chemical electrode systems often suffer from drawbacks such as frequent recalibration and ion cross sensitivity, limiting their suitability for long-term and on-site monitoring. In response to these challenges, we present a novel and cost-effective electrochemical sensor based on a copper–cobalt-based electrochemical sensor for reliable nitrate detection. The sensor exhibits a remarkable true detection limit of 0.19 µM and a limit of quantification of 4.41 µM and demonstrates high selectivity even in the presence of commonly interfering ions such as Mg²⁺, SO₄^2-, Zn²⁺, K⁺, NH₄⁺, Fe²⁺, and Na⁺. Owing to its sensitivity, selectivity, and portability, the developed sensor offers a promising solution for real-time, on-site monitoring of nitrate concentrations in both water and soil samples.