Electronic waste derived reduced graphene oxide supported silver nanoparticles for the electrochemical sensing of trace level arsenite in aqueous medium

The presence of heavy metals, particularly arsenic (As), in water poses a significant threat to human health. As a result, a feasible method for its on-site detection is required for the monitoring of As in drinking water. In this study, we investigated a glassy carbon electrode (GCE) modified by reduced graphene oxide supported silver (rGO/Ag) nanocomposite for sensing arsenite (As(III)) in aqueous medium. The graphene oxide (GO) was synthesized using graphite collected from a wasted dry cell using the improved Hummer method and the rGO/Ag nanocomposite was prepared via a straightforward chemical reduction process where Ag(I) was reduced to Ag nanoparticles simultaneously with the reduction of GO to rGO. The resulting GO, rGO, and rGO/Ag nanocomposite were thoroughly characterized using various analytical techniques, including transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We used cyclic voltammetry and differential pulse anodic stripping voltammetry (DPASV) to study the electrochemical sensing of As(III). Through meticulous optimization of experimental parameters (predeposition potential = −0.4 V, predeposition time = 120 s) of DPASV, the detection of As(III) at the rGO/Ag modified GCE was able to achieve a sensitivity of 1.24 μA/ppb and a detection limit of 0.24 ppb. Moreover, the rGO/Ag modified GCE can be used to detect As(III) in a complex system containing various interfering metal ions, allowing for selective and sensitive analysis. Finally, the rGO/Ag modified GCE can also be used to detect As(III) in a real water sample.