A ratiometric fluorescence sensor based on carbon quantum dots realized the quantitative and visual detection of Hg 2

In this paper, based on the fluorescence of carbon quantum dots (CQDs) quenched by mercury ions (Hg ) and the nonresponse of Hg to rhodamine B fluorescence, a dual emission ratio fluorescence sensor was constructed to realize the quantitative detection of Hg . Under excitation at 365 nm, the fluorescence spectrum showed double emission peaks at 437 nm and 590 nm, corresponding to the fluorescence emissions of CQDs and rhodamine B, respectively. This method quantitatively detected Hg based on the linear relationship between the ratio of the intensities of the two emission peaks F /F and the concentration of Hg . The detection range was 10-70 nM, and the limit of detection (S/N = 3) was 3.3 nM. In addition, this method could also realize the qualitative and semiquantitative detection of Hg according to the fluorescence colour change of the probe under ultraviolet light. After various evaluations, the method could be successfully applied to the quantitative and visual detection of Hg in tap water, and demonstrated excellent selectivity, anti-interference performance, and repeatability of the method.