A Novel Fluorescent Nanoswitch Based on Carbon Dots for Sensitive Detection of Hg2+ and I−

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg 2 + and I − . The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440 nm. The fluorescence of the CDs can be selectively quenched by Hg 2 + ion, and then the I − was added into the system, which can interact with Hg 2 + and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg 2 + has obtained a satisfactory linear relationship covering the linear range of 0–50 μ M with the linear relationship ( R 1 2 = 0 . 9 9 9 1 ), and the limit of detection is 0.047 μ M. The additions of I − could lead to the fluorescence intensity of the solution of CDs and Hg 2 + (50 μ M) recover rapidly, which is linearly related ( R 2 2 = 0 . 9 9 5 7 ) to the concentration of I − in the range from 0 to 70 μ M, the detection limit for I − was calculated to be 0.084 μ M. Moreover, the developed method to detect Hg 2 + and I − was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg 2 + and I − over some potentially interfering ions, the recoveries were up to 97.8–107.0% and 96.7–106.6%, respectively.