Analytical performance and stability studies of CoAu/rGO-based electrochemical sensor for arsenic(III) detection in aqueous solutions
Kristina Radinović, Jadranka Milikić, Nemanja Gavrilov, Dalibor Stanković, Aleyna Basak, Önder Metin, Biljana Šljukić
Abstract
Cobalt-gold nanoparticles (CoAu) were grafted on reduced graphene oxide (rGO) using a simple, scalable procedure. As-prepared CoAu/rGO nanocomposites were employed as electrode materials to detect trace amounts of arsenic(III) ions (As 3+ ) in aqueous samples using anodic stripping voltammetry. CoAu/rGO was thoroughly tested in the presence of As 3+ in a neutral medium (bicarbonate buffer, pH = 7), and the limit of detection was found to be as low as 1.51 ppb, significantly lower than the maximum permissible value set by the World Health Organization at 10 ppb. Its possible sensor application was confirmed by the preserved response to As 3+ ions in samples simultaneously containing interferents such as Cu 2+ ions. The real-life application of this material was validated by the determination of As 3+ ions in real samples from the city water supply system (the city of Zrenjanin in Vojvodina) and rivers (the Begej River, the Drina River and the Danube River). Besides the high sensitivity of CoAu/rGO towards As 3+ ions, its stability was also monitored over a certain time, demonstrating that it can be used with great precision in sensors for routine water analysis over extended periods. Overall, this study offers a green, highly stable, accurate and precise electrochemical platform for arsenic detection that requires reagent-free sample preparation.