Sensitive and selective determination of trace amounts of mercury ions using a dimercaprol functionalized graphene quantum dot modified glassy carbon electrode

A novel nanomaterial is synthesized based on the functionalization of graphene quantum dot with dimercaprol (GQD-DMC). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (TEM) are used to approve the successful synthesis of GQD-DMC. The synthesized nanomaterial is used as an electrode modifier for the sensitive and selective determination of mercury( ii ) ions in real water samples. The method of evaluation is based on the pre-concentration of mercury ions on the GQD-DMC modified glassy carbon electrode, reduction of Hg( ii ), and anodic stripping voltammetric measurement of these reduced ions in a buffer solution. The pre-concentration of mercury ions is driven by the affinity interaction between the surface containing functional groups of DMC and Hg( ii ) ions. The GQD-DMC modified glassy carbon electrode (GQD-DMC/GCE) shows extra sensitivity and selectivity for mercury( ii ) detection, which is assumed to be due to the increased surface area as well as the presence of sulfur-containing functional groups on the modified structure. A new catalyst was prepared by covalent functionalization of graphene quantum dot with dimercaprol (GQD-DMC) and applied, for the first time, as an electrode modifier for the preparation of an Hg( ii ) electrochemical sensor.