L-半胱氨酸修饰CdTe量子点的合成及其对Cu^(2+)的荧光猝灭检测

Synthesis of L-cysteine-modified CdTe quantum dots and detection of Cu^(2+) based on its fluorescence quenching effect on CdTe quantum dots

采用水相合成法,在氮气保护加热回流条件下,以L-半胱氨酸为稳定剂合成了水溶性的CdTe量子点,并通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、荧光光谱(PL)和紫外可见光谱(UV-Vis)对样品进行了表征。结果表明所合成的量子点为立方闪锌矿结构,形状为球形,粒径2~4nm;以罗丹明6G为参照标准,回流时间为2h合成的CdTe量子点的荧光量子产率为45.08%。当CdTe量子点浓度为3.2×10-5mol/L、反应时间为3h时,其荧光猝灭程度与Cu2+浓度在400~4000nmol/L范围内呈良好的线性关系,线性相关系数为0.99601,方法检出限为85nmol/L。

L-cysteine-capped CdTe quantum dots( QDs) have been synthesized in aqueous solution under refluxing conditions with nitrogen protection. The samples were characterized by X-ray diffraction( XRD),transmission electron microscopy( TEM),photoluminescence( PL) spectroscopy and ultraviolet –visible( UV –Vis) spectroscopy.CdTe QDs are spherical particles with a cubic zinc blende structure,have a diameter size of 2- 4 nm and have high dispersibility. With a refluxing time of 2 h,the fluorescence quantum yield of as-prepared CdTe QDs was found to be 45. 08% by using rhodamine 6G( 95%) as the reference standard. When the concentration of quantum dots was 3. 2 × 10- 5mol / L and the reaction time was 3 hours,the relative fluorescence intensity decreased linearly with the concentration of Cu2 +in the range 400- 4000 nmol / L; the correlation coefficient was 0. 99601,and the limitation of detection reached 85 nmol / L.