▎ 摘　　要

Graphene quantum dots were prepared by ultrasonic route and served as a highly selective water-soluble probe for sensing of Hg2+. The fluorescence emission spectrum of graphene quantum dots was at about 430 nm. In the presence of Hg2+, the fluorescence of the quantum dots significantly quenched. And the fluorescence intensity gradually decreased with the increasing concentration of Hg2+. The change of fluorescence intensity is directly proportional to the concentration of Hg2+. Under optimum conditions, the linear range for the detection of Hg2+ was 8.0 x 10(-7) to 9 x 10(-6) M with a detection limit of 1.0 x 10(-7) M. In addition, the preliminary mechanism of fluorescence quenching was discussed in the paper. The constructed sensor with high sensitivity and selectivity, simple, rapid properties makes it valuable for further application. (C) 2014 Elsevier B.V. All rights reserved.