Water is a precious resource that is under threat from a number of pressures, including, for example, release of toxic compounds, that can have damaging effect on ecology and human health. The current methods of water quality monitoring are based on sample collection and analysis at dedicated laboratories. Recently, electrochemical-based methods have attracted a lot of attention for environmental sensing owing to their versatility, sensitivity and their ease of integration with cost effective, smart and portable readout systems. In the present work, we report on the fabrication and characterization of platinum-based interdigitated microband electrodes arrays, and their application for trace detection of copper. Using square wave voltammetry after acidification with mineral acids, a limit of detection of 0.8 μg/L was achieved. Copper detection was also undertaken on river water samples and compared with standard analytical techniques. The possibility of controlling the pH at the surface of the sensors—thereby avoiding the necessity to add mineral acids—was investigated. By applying potentials to drive the water splitting reaction at one comb of the sensor’s electrode (the protonator), it was possible to lower the pH in the vicinity of the sensing electrode. Detection of standard copper solutions down to 5 μg/L (ppb) using this technique is reported. This reagent free method of detection opens the way for autonomous, in situ monitoring of pollutants in water bodies.

The increasing global population is putting huge pressure on food production system. The improper use of fertilizers, in particular, is contributing to climate change and biodiversity loss. Existing soil monitoring techniques have serious shortcomings as they are lab based and have slow turnaround times. New digital approaches are therefore urgently required to provide timely, actionable, local data on soil and water quality across each field on a farm to maximize crop yield, eliminate waste and minimize environmental pollution. To this end, we present a reagent-free, easy-use, cost-effective, accurate electrochemical phosphate sensor with a limit of detection of 10.4 nM and sensitivity of 1.18 A/nM to allow continuously, in-field soil phosphate monitoring.

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 detection limit of 0.19 µM and demonstrates high selectivity even in the presence of commonly interfering ions such as Mg²⁺, SO₄²⁻, 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