Electrodes modified with clickable thiosemicarbazone ligands for sensitive voltammetric detection of Hg(II) ions

The synthesis of a series of thiosemicarbazone ligands bearing azido groups, which were further immobilized on the surface of phenylethynyl-functionalized glassy carbon (GC) electrodes through a Cu(I)-catalyzed click reaction is reported. The modified electrodes presented a remarkable selectivity towards Hg(II) among other metal ions. Under optimized conditions and using the accumulation at open circuit-anodic stripping technique, detection limits below nanomolar level were obtained for Hg(II). Further, we demonstrated that GC electrodes clicked with thiosemicarbazone ligands can be used successfully for the analysis of Hg(II) ions from water samples. Moreover, the modified electrodes showed a very good reproducibility, stability over time and reusability, and can therefore be employed as sensitive and selective sensors for Hg(II) ion analysis in environmental samples.