柠檬基碳量子点/铜纳米团簇比率型荧光探针对环境水中Hg^(2+)检测的应用

Application of ratiometric fluorescence probe composed of copper nanoclusters and carbon quantum dots based fresh lemon juice on Hg2+detection in environmental water

本文以新鲜柠檬汁为碳源,利用一步水热法合成了具有荧光性能良好的荧光碳量子点(CQDs)和谷胱甘肽封端的铜纳米簇(CuNCs).由荧光光谱分析可知,在同一激发下,CQDs和CuNCs分别在420 nm和650 nm处有明显特征荧光发射峰值.将二者按一定比例构建了CQDs-CuCNs双荧光探针,并用于水环境中汞离子的荧光检测.结果发现,Hg^(2+)加入CQDs-CuCNs双荧光体系后,该荧光探针在420 nm处荧光发射峰值下降,但在650 nm处荧光发射峰值略微上升.将该双荧光探针的荧光发射峰值的比值I650/I420(在650 nm处与420 nm处的荧光发射峰值的比值)与汞离子浓度进行线性回归,结果在Hg^(2+)浓度25—400 nmol·L^(-1)范围内呈现良好线性(R2=0.9965),检出限为13.0 nmol·L^(-1).该荧光探针对湖水和污水厂出水中Hg^(2+)均未检出,但实际样品加标回收率在94.12%—103.31%之间,相对标准偏差均小于4.52%,表明该方法适用于实际水样中汞离子的快速检测.

In this paper,fluorescent carbon quantum dots(CQDs)with good fluorescence performance were synthesized by a one-step hydrothermal method using fresh lemon juice as the carbon source,and copper nanoclusters(CuCNs)were synthesized using glutathione and copper sulfate as the raw materials,and the fluorescence spectra analysis showed that both CQDs and CuCNs had obvious characteristic fluorescence emission peaks at 420 nm and 650 nm,respectively,under the same excitation wavelength.The dual fluorescent probes of CQDs-CuCNs were constructed in a certain proportion and applied to the fluorescence detection of mercury ions in the actual environmental water.During mercury ion spiked into the dual fluorescent system of CQDs-CuCNs,the fluorescence emission peak at 420 nm(luminescence of CQDs)was quenched,but the peak at the 650 nm(luminescence of CuCNs)was stable.Moreover,the fluorescence intensity of the CQDs based lemon was quenched gradually with increasing amounts of Hg(Ⅱ).The ratio of fluorescence emission intensity I650/I420,which is defined as the intensity ratio of fluorescence emission peak at 650 nm to that at 420 nm,was found to be good linear relationship(R2=0.9965)with Hg(Ⅱ)concentration in the range of 25—400 nmol·L^(−1),and the detection limit was 13.0 nmol·L^(−1).The fluorescent probe for detection Hg(Ⅱ)in lake water and effluent of wastewater treatment plant were not detected,but the standard addition recovery rate of Hg(Ⅱ)in the actual water were between 94.12%and 103.31%,and relative standard deviation(RSD)were less than 4.52%.These results show that the ratiometric fluorescent probes are suitable for the rapid detection of mercury ions in real water samples.