▎ 摘　　要

Simultaneous determination of Cd(II), Pb(II), As(III) and Hg(II) metal ions was carried out based on the synergistic effect of graphene oxide (GO) textured with redox active ruthenium(II) bipyridine complex ([Ru(bpy)(3)](2+)). ([Ru(bpy)(3)](2+)-GO nanocomposite on the modified gold (Au) electrode acts as an electrocatalyst and favours the sensitive and selective detection of metal ions. Also, it exhibited an enhanced electron transfer rate with a low solution resistance examined by cyclic voltammetry and impedance analysis. The inherent electrochemical and electrocatalytic behaviours of ([Ru(bpy)(3)](2+)-GO on gold electrode were demonstrated for simultaneous detection of heavy metal ions in water matrix. The proposed sensor exhibited a higher sensitivity towards Cd(II), Pb(II), As(III) and Hg(II) metal ions with a lowest detection limit of 2.8, 1.41, 2.3 and 1.6 nM respectively. The observed detection limits were less than the World Health Organization standards and hence the developed sensor can be deployed for detecting heavy metal ions in water bodies. Simultaneous electrochemical detection of heavy metal ions in river and tap water was carried out using the developed sensor and the observed results were validated with atomic absorption spectroscopy.