AuNPs-SPCE: A versatile sensor for multi-heavy metal detection in water

In this study, a novel electrochemical sensor was developed, utilizing screen-printed carbon electrodes modified with gold nanoparticles (AuNPs-SPCE), for the simultaneous detection of cadmium (Cd(II)), lead (Pb(II)), arsenic (As(III)), and mercury (Hg(II)) in water. The particle shape of AuNPs significantly impacted the performance of detecting multiple HMs. Using differential pulse voltammetry (DPV), the electrochemical measurement involved two steps: (i) electrodeposition of heavy metal ions onto the working electrode, followed by (ii) anodic stripping in solution. Under optimized conditions with a 0.1 M HCl electrolyte solution, the modified SPCE was capable of both single and simultaneous detection of Cd(II), Pb(II), As(III), and Hg(II). To demonstrate the applicability coupled with portable potentiostat, the simultaneous detection of Cd(II), Pb(II), As(III), and Hg(II) in tap water was performed. A linear relationship was observed between the concentration of each metal ion and the corresponding stripping current signal, with detection ranges of 10–500 ppb for Cd(II), 10–1000 ppb for Pb(II), 10–500 ppb for As(III), and Hg(II). The limits of detection were approximately 9.4 ppb for Cd(II), 4.4 ppb for Pb(II), 7.6 ppb for As(III), and 1.5 ppb for Hg(II). These results highlight the potential of the AuNPs-SPCE for highly sensitive and specific detection of HMs in real water samples.