▎ 摘　　要

As the newest two members of the carbon materials family, carbon dots (CDs) and graphene oxide (GO) possess many excellent optical properties resulting in a wide range of applications. In this work, we successfully synthesized CDs with a high-quantum-yield, and labeled them on oligodeoxyribonucleotide (ODN). The fluorescence of resultant CDs-labeled oligodeoxyribonucleotide (ODN-CDs) was quenched by GO via fluorescence resonance energy transfer. In the presence of Hg2+, the fluorescence was recovered by the release of ODN-CDs from GO due to the formation of T-Hg2+-T duplex. In the light of this theory, we designed a simple, highly sensitive and selective fluorometric Hg2+ sensor based on CDs-labeled oligodeoxyribonucleotide and GO without complicated, costly and time-consuming operations. Under the optimal conditions, a linear relationship was obtained between relative fluorescence intensity and the concentration of Hg2+ in the range of 5-200 nM (R-2=0.974). The present GO-based sensor system is highly selective toward Hg2+ over a wide range of metal ions and has a detection limit of 2.6 nM. This method is reliable, and has been successfully applied for the detection of Hg2+ in practical samples. (C) 2014 Elsevier B.V. All rights reserved.