Bismuth Silver Sulfide (AgBiS2) Nanoparticle-Modified SPEs Enabling Concurrent Lead and Cadmium Analysis

The development of quick, accurate, and field-deployable detection techniques is required due to the growing environmental pollution caused by heavy metals, especially lead (Pb) and cadmium (Cd). In this work, bismuth silver sulfide (AgBiS2) nanoparticles are synthesized using a simple hydrothermal method aided by biomolecules, and they are used as a new modifier forPb(II) and Cd(II) simultaneous electrochemical detection using screenprinted electrodes (SPEs). After thorough material characterisation, pure, highly crystalline, quasi-spherical AgBiS2 nanoparticles produced with an average diameter of around 20 nm. The AgBiS2/SPE sensor demonstrated a threefold decrease in charge transfer resistance, indicating a considerable improvement in electrochemical performance. The sensor showed outstanding analytical performance under optimal SWASV, or square wave anodic stripping voltammetry conditions, with broad linear ranges and low 0.21 µg/L for Pb(II) and 0.15 µg/L for Cd(II) are the detection limits, both of which are far below WHO recommendations. Along with demonstrating great selectivity, good repeatability, and long-term stability,The sensor was successfully used to analyze real water samples, highlighting its promise as an affordable and reliable instrument for on-site environmental monitoring.