Zn_(0.15)Cd_(0.85)S量子点复合材料的合成及其对Cu^(2+)的超灵敏测定

Ultrasensitive Cu^(2+) sensing by Zn_(0.15)Cd_(0.85)S composite quantum dots

合成了高质量的半胱氨酸修饰Zn0.15Cd0.85S量子点复合材料.利用Cu2+对量子点荧光的猝灭作用,实现了Cu2+的定量检测.所合成的Zn0.15Cd0.85S量子点对其他常见的金属离子几乎没有响应,表明该方法具有较好的选择性.在优化条件下,Zn0.15Cd0.85S量子点荧光的猝灭程度与Cu2+浓度呈良好的线性关系,线性范围为6.0nM～1.0μM,检出限为1.0nM.对0.5μM标准溶液平行测定11次,相对标准偏差为2.0%.利用标准加入法对水样中Cu2+含量进行了测定,结果令人满意.

The high quality Zn0.15Cd0.85S composite quantum dots （QDs） that capped with L-cysteine were synthesized and applied for ultrasensitive Cu^2＋ sensing. The fluorescence of the as-obtained Zn0.15Cd0.85S QDs was quenched only by Cu^2＋. A variety of other common metal ions hardly influenced the fluorescence of the QDs,indicating good selectivity of the method. The response of the optical sensor was linearly proportional to the concentration of Cu^2＋ ranging from 6.0 nM to 1.0 μM. The detection limit was 1. 0 nM. A relative standard deviation of 2.0% for 11 replicates of a 0.5 μM Cu^2＋ solution was obtained. The proposed method has been successfully applied to the detection of Cu^2＋ in tap water.