Green Synthesis of Fluorescent Carbon Quantum Dots for Detection of Hg2+

Fluorescent carbon quantum dots (CQDs) were synthesized by one-step hydrothermal treatment with apple juice as raw material. The result indicated that the fluorescence could be quenched by Hg2+ with high specificity. Based on this phenomenon, a selective and sensitive sensor was constructed for the detection of Hg2+ in phosphate solutions (pH 7.0). The fluorescence intensity showed linear responses with Hg2+ concentration ranging from 5.0 to 100.0 nM and 1.0 to 50.0 mu M, with the detection limit of 2.3 nM (S/N = 3). The as-fabricated sensor was further extended for the determination of Hg2+ in real water samples.