Mechanistic insights into high-performance and selective Cd(II) detection using Ag2WO4 nanoparticle-based electrochemical sensors for real-world applications

The electrochemical detection of cadmium (Cd(II)) is essential for environmental monitoring due to its high toxicity and persistence in aquatic ecosystems. This study presents a silver tungstate nanoparticle (Ag₂WO₄ NPs)-modified glassy carbon electrode (GCE) as a sensitive and selective electrochemical sensor for Cd(II) detection. The strong interaction between Cd(II) ions and the active sites of Ag₂WO₄ NPs, combined with the material's redox-active properties, enhances electron transfer, resulting in improved conductivity and signal response. The sensor demonstrated excellent performance, with a broad linear detection range from 10 to 260 ppb and an impressive detection limit of 2.022 ppb, which is well below the permissible limits for drinking water set by regulatory agencies. The sensor's practical applicability was validated using real-world water samples, including tap water, groundwater and river water, with minimal interference from co-existing ions. The relative standard deviation (RSD) values ranged from 0.69 % to 6.59 %, confirming its reliability in complex environmental matrices. These results highlight the potential of Ag₂WO₄ NPs-based electrochemical sensors as cost-effective, reliable, and efficient tools for real-time monitoring of heavy metal contamination in diverse environmental conditions.