Improving the voltammetric determination of Hg(II): a comparison between ligand-modified glassy carbon and electrochemically reduced graphene oxide electrodes

A new thiosemicarbazone ligand was immobilized through a Cu(I)-catalyzed click reaction
on the surface of glassy carbon (GC) and electrochemically reduced graphene oxide (GC-ERGO)
electrodes grafted with phenylethynyl groups. Using the accumulation at open circuit followed by
anodic stripping voltammetry, the modified electrodes showed a significant selectivity and sensibility
for Hg(II) ions. A detection limit of 7 nM was achieved with the GC modified electrodes. Remarkably,
GC-ERGO modified electrodes showed a significantly improved detection limit (0.8 nM), sensitivity,
and linear range, which we attribute to an increased number of surface binding sites and better
electron transfer properties. Both GC and GC-ERGO modified electrodes proved their applicability
for the analysis of real water samples.