荧光碳量子点的制备及其对Hg^(2+)检测性能研究

The Preparation of Fluorescence Carbon Quantum Dots for Hg^(2+)Detection

以邻苯二胺为原料,通过溶剂热法成功制备出了黄色荧光碳量子点(CDs),并对溶剂热反应时间和pH值进行了优化,采用红外光谱、紫外光谱、荧光光谱、透射电子能谱、X射线光电子能谱法对CDs的形貌和结构进行了表征。试验测得所制备出的CDs荧光量子产率为26%,荧光寿命为0.87 ns,最可几粒径为2.1 nm。在此基础上进一步考察了CDs的荧光响应性能,发现CDs的荧光发射强度和波长对pH、激发波长、溶剂具有依赖特性,且Hg^(2+)对CDs存在选择性荧光猝灭效应,可用于水中痕量Hg^(2+)的检测。研究表明:CDs在574 nm处的荧光强度随Hg^(2+)浓度逐渐增加而降低,Hg^(2+)浓度在50~300μM范围内时,CDs荧光强度与Hg^(2+)浓度间具有良好的线性关系,相关系数(R^(2))为0.9714,检出限(LOD)为1.76μM,加标回收率为96.5%~104.5%,相对标准偏差(RSD)为4.43%。

Yellow-visual fluorescent carbon quantum dots were successfully prepared by solvothermal method,using o-phenylenediamine as the raw material.The reaction time and pH value were then carefully optimized.The morphology and structural properties of CDs were characterized by infrared spectroscopy,ultraviolet spectroscopy,fluorescence spectroscopy,transmitted electron spectroscopy and X-ray photoelectron spectroscopy.The fluorescence quantum yield of the prepared CDs is 26%,the fluorescence lifetime is 0.87 ns,and the highest possible particle size is 2.1 nm.The fluorescence response of CDs was further investigated,and it was found that the fluorescence emission intensity and wavelength of CDs was dependent on pH,excitation wavelength,and the solvent,and Hg^(2+)had a selective fluorescence quenching effect on CDs,which could be used for the detection of trace Hg^(2+)in water.The fluorescence intensity of CDs at 574 nm decreased with the increase of Hg^(2+)concentration,and a good linear relationship was found in the range of 50~300μM.The correlation coefficient(R^(2))was 0.9714,and the limit of detection(LOD)was 1.76μM.The recovery was 96.5%~104.5%with a relative standard deviation(RSD)of 4.43%.