Co掺杂ZnS量子点荧光探针检测水体中Pb^2+和Cu^2+

Co-doped ZnS quantum dots as fluorescent probe in the determination of Pb^2+and Cu^2+in tap water

目的以L-半胱氨酸作为表面修饰剂,采用水热法合成掺杂Co的ZnS量子点(ZnS:Co),并通过此量子点构建对Pb^2+和Cu^2+的荧光检测探针。方法通过X射线衍射(X-ray diffraction,XRD)、透射电子显微镜(transmission electron microscope,TEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和光致发光光谱(photoluminescence spectroscopy,PL)对样品进行表征和分析。结果ZnS:Co量子点为立方闪锌矿结构,颗粒呈不规则球形,平均粒径约为4.51 nm。ZnS:Co量子点相较纯ZnS量子点荧光强度增强了近4倍。基于ZnS:Co量子点构建了对Pb^2+和Cu^2+的荧光检测。Pb^2+和Cu^2+的加入会引起ZnS:Co量子点的荧光淬灭,ZnS:Co量子点只对Pb^2+和Cu^2+离子表现出良好的荧光响应,并且表现出良好的抗干扰能力。结论ZnS:Co量子点可以实现对水体中Pb^2+和Cu^2+的荧光检测。

Objective Using L-cysteine as a surface modifier,to synthesize Co-doped ZnS quantum dots(ZnS:Co)by a hydrothermal method,and construct fluorescence detection probes for Pb^2+and Cu^2+by the quantum dots.Methods The samples was characterized and analyzed by X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS),and photoluminescence spectroscopy(PL).Results ZnS:Co quantum dots had a cubic sphalerite structure with irregular spherical particles and the average particle size of about 4.51 nm.Compared with pure ZnS quantum dots,the fluorescence intensity of ZnS:Co quantum dots was nearly 4 times stronger.Based on ZnS:Co quantum dots,the fluorescence detection of Pb^2+and Cu^2+was constructed.The addition of Pb^2+and Cu^2+could cause the fluorescence quenching of ZnS:Co quantum dots.ZnS:Co quantum dots only showed good fluorescence response to Pb^2+and Cu^2+ions,and showed good interference immunity.Conclusion ZnS:Co quantum dots can achieve fluorescence detection of Pb^2+and Cu^2+in water.