Adsorptive stripping voltammetry determination of hexavalent chromium by a pyridine functionalized gold nanoparticles/three-dimensional graphene electrode

An electrode modified with pyridine functionalized gold nanoparticles and three-dimensional graphene was prepared and employed for the voltammetry determination of hexavalent chromium. Graphene oxide was electrochemically reduced on glassy carbon electrode. Gold nanoparticles were electrodeposited on the surface of graphene under constant potential. Pyridine group anchored on gold nanoparticles by self-assembly. The modified materials were characterized by scanning electron microscopy, Raman spectroscopy and electrochemical technique. Each step of modification was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The prepared electrode exhibited high current response towards hexavalent chromium by differential pulse adsorptive stripping voltammetry. Under optimal condition, the linear response for hexavalent chromium was achieved in the concentration range from 25 to 300 μg/L, with a detection limit of 1.16 μg/L. Moreover, the prepared electrode showed excellent selectivity, reproducibility and stability. Finally, the prepared electrode was applied to detect hexavalent chromium in real sample with satisfactory results. •An electrochemical sensor was prepared based on pyridine functionalized gold nanoparticles and three-dimensional graphene.•The prepared electrode was employed for hexavalent chromium detection by adsorptive stripping voltammetry.•The prepared electrode exhibited highly sensitivity and selectivity in the determination of hexavalent chromium.•The proposed method was successfully applied to detect hexavalent chromium in real water samples.