Application of 3D gold nanotube ensembles in electrochemical sensing of ultra-trace Hg (II) in drinkable water

As a novel and highly sensitive sensor, three-dimensional gold nanoelectrode ensembles (3D GNE) prepared by gold deposition inside the parallel pores of a porous template have been successfully applied in electrochemical determination experiments. In this study, we report on the fabrication of 3D gold nanotubes (GNT) and their application in determination of Hg (II) in water. The morphology and crystal structure of the 3D GNT were characterized by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD), respectively. The sensitivity of the fabricated electrode towards Hg (II) was examined using anodic stripping voltammetry (ASV) as a powerful technique in determination experiments. Under the optimized conditions, a linear response was achieved over a wide range (0.1-50 nM) for Hg (II) with a sensitivity of 0.247 µA/nM. The 3D GNT electrode exhibited good repeatability and reproducibility and a detection limit of 0.06 nM (S/N = 3) was achieved which is much lower than the limit set by the Environmental Protection Agency (EPA) for Hg (II) in drinkable water.