All-in-one electrochemical platform with integrated O₂-filtering electrocatalyst towards on-site simultaneous ultratrace detection of multiple heavy metals in real water samples

An advanced and miniaturized electrochemical platform has been developed for the sensitive detection of heavy metal ions (Hg²⁺, Pb²⁺, and As³⁺) in real water samples using differential pulse voltammetry (DPV). Built on a commercial, disposable dual screen-printed carbon electrode (SPCE), the system features a novel design in which one carbon working electrode is modified with Au nanofoam and Pt nanoparticles, functioning as an integrated electrocatalytic oxygen filter. This localized removal of dissolved oxygen effectively overcomes a major limitation in electroanalytical sensing, enabling accurate detection on the second working electrode, coated with a polypyrrole film, Au nanofoam, and WS₂ nanosheets, without interference from oxygen reduction. This innovative configuration eliminates the need for time-consuming sample purging and allows precise and reliable detection of trace heavy metal ions in complex matrices, even without stirring the solution during the preconcentration step. The platform achieves detection limits (LODs) below the Environmental Protection Agency (EPA) standards for drinking water and matches the performance of conventional three-electrode systems that require extensive sample handling and larger volumes. Validated on real samples from Tunisian tap water and Mejerda River, the system demonstrates strong practical utility and reliability. These findings highlight the potential of this innovative technology for rapid, on-site water quality monitoring, paving the way for its integration into portable detection devices. • Dual SPCE for simultaneous O 2 filtering and ultratrace multiple heavy metal detection • Built on a commercial platform, without complex engineering or unsafe electrodes • Accurate heavy metal detection free from oxygen interference without sample purging • Ultrasensitive heavy metal detection below EPA limits in complex sample matrices