▎ 摘　　要

This work designs a new electrochemical sensing platform for the quantitative monitoring of mercury ion (Hg2+) on poly-T-(15) oligonucleotide-functionalized graphene oxide by coupling with DNase I-assisted target recycling amplification. The assay was carried out on the basis of T-Hg2+-T coordination chemistry by using target-induced dissociation of indicator-labeled poly T(15) oligonucleotide from graphene oxide nanosheets. The electronic signal was amplified through DNase I-triggered target recycling. Experimental results indicated that the amperometric response of DNA-based sensing platform deceased with the increasing Hg2+ concentration in the sample, and has a detection limit of 0.12 nM with a dynamic working range of up to 50 nM. Our strategy afforded exquisite selectivity for Hg2+ against other environmentally related metal ions. More significantly, this methodology displayed high reproducibility and acceptable accuracy, thus representing an optional sensing scheme for the screening of Hg2+ in environmental water samples. (C) 2016 Elsevier B.V. All rights reserved.