ZnS:Mn^(2+)掺杂型纳米晶应用于Cd^(2+)的荧光测定

Fluorescence Assay for the Determination of Cd^(2+) Based on ZnS:Mn^(2+) Nanocrytals Capped Mercaptoacetic Acid

以巯基乙酸为表面修饰剂制备了稳定性和水溶性均优的掺杂型ZnS:Mn2+纳米晶溶胶并应用于金属Cd2+的检测。在pH7.7的Tris-HCl缓冲介质中,Cd2+的加入使ZnS:Mn2+体系的荧光显著增强,强度变化与Cd2+的浓度呈良好的线性关系,其线性范围为5.0×10-7-8.9×10-5mol.L-1,方法检测下限为3.08×10-8mol.L-1。该方法应用于湖水中Cd2+的检测,回收率为93.7-97.4%。同时利用荧光光谱、紫外可见吸收光谱及XRD谱研究了ZnS:Mn2+纳米晶结构及其溶液的光谱特性,并对识别Cd2+的可能机理进行了探讨。

Mn2＋-doped ZnS nanocrystal were prepared with mercaptoacetic acid as a stabilizer.The QDs possessed good stability and water-solubility which was applied for determination of cadmium ions（Ⅱ）.In the Tris-HCl buffer with pH=7.7,it was found that the presence of Cd2＋ enhanced the intensity of fluorescence of ZnS：Mn2＋.The increase of the intensity was proportion of good linear relations with the Cd2＋ concentration.The linear range was 5.0×10-7-8.9×10-5 mol·L-1 with detection limit as 3.08×10-8 mol L-1.This method was used to the determination of Cd2＋ in discharged water,the recovery was 93.7-97.4%.The properties of ZnS：Mn2＋ nanocrystal and its hydrosol solution were studied via fluorescence spectrum,UV-vis absorption spectrum and X-ray diffraction（XRD）.And the possible mechanism was also discussed.