A Novel Fluorescent Nanoswitch Based on Carbon Dots for Sensitive Detection of Hg and I.

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg and I. The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440nm. The fluorescence of the CDs can be selectively quenched by Hg ion, and then the I was added into the system, which can interact with Hg and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg has obtained a satisfactory linear relationship covering the linear range of 0-50M with the linear relationship (), and the limit of detection is 0.047M. The additions of I could lead to the fluorescence intensity of the solution of CDs and Hg (50M) recover rapidly, which is linearly related () to the concentration of I in the range from 0 to 70M, the detection limit for I was calculated to be 0.084M. Moreover, the developed method to detect Hg and I was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg and I over some potentially interfering ions, the recoveries were up to 97.8-107.0% and 96.7-106.6%, respectively. A water-soluble fluorescent nanoswitch of carbon dots (CDs) has been designed for detecting Hg and I, which was fabricated by hydrothermal process. Hg ions can be recognized by the amino groups of the CDs to form charge-transfer state and result in quenching fluorescence of the CDs. After adding I ions to the system of CDs/ Hg, the Hg ions were extracted from the CDs due to the stronger binding between Hg and I, leading to the released CDs having restrained the photo-induced electron transfer and recovered the fluorescence. [ABSTRACT FROM AUTHOR]