Electrochemical Deposition of Gold Nanoparticles on Reduced Graphene Oxide by Fast Scan Cyclic Voltammetry for the Sensitive Determination of As(III)

In this study, a stable, sensitive electrochemical sensor was fabricated by the electrochemical codeposition of reduced graphene oxide (rGO) and gold nanoparticles on a glassy carbon electrode (rGO-Au_nano/GCE) using cyclic voltammetry (CV), which enabled a simple and controllable electrode modification strategy for the determination of trace As(III) by square wave anodic stripping voltammetry (SWASV). SWASV, CV, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the electrochemical properties and morphology of the proposed sensing platform. The number of sweep segments, the deposition potential and the deposition time were optimized to obtain ideal sensitivity. The presence of rGO from the electroreduction of graphene oxide on the sensing interface effectively enlarged the specific surface area and consequently improved the preconcentration capacity for As(III). The rGO-Au_nano/GCE sensor exhibited outstanding detection performance for As(III) due to the combined effect of Au_nano and rGO formed during the electroreduction process. Under the optimized conditions, a linear range from 13.375 × 10⁻⁹ to 668.75 × 10⁻⁹ mol/L (1.0 to 50.0 μg/L) was obtained with a detection limit of 1.07 × 10⁻⁹ mol/L (0.08 μg/L) (S/N = 3). The reproducibility and reliability of the rGO-Au_nano/GCE sensor were also verified by performing 8 repetitive measurements. Finally, the rGO-Au_nano/GCE sensor was used for the analysis of real samples with satisfactory results.