An electrochemical detection of Hg2+ ion using graphene oxide as an electrochemically active indicator

An electrochemical Hg2+ ion sensor was developed in which graphene oxide (GO) was employed as an indicator for electrochemical signal generation. The Gold surface modified with thiol-functionalized poly-T-oligonucleotides was exposed to an Hg2+ ion solution. It is because Hg2+ ions are inserted between T-T mismatched base pairs to form a T-Hg2+-T bond, the structure of the DNA transitioned from a single-stranded to a double-stranded form. The surface was exposed to an aqueous solution of GO for immobilizing GO on the surface. The current required for the electrochemical reduction of GO was monitored on the resulting surface, which exhibited a linear response over a 1-300 nM range of Hg2+ ion concentrations and a high selectivity toward Hg2+ ion. (C) 2012 Elsevier B.V. All rights reserved.