CdSe/ZnS量子点荧光猝灭法测定农药甲胺磷

Fluorescence quenching method for the determination of methamidophos using CdSe/ZnS quantum dots

基于农药甲胺磷对CdSe/ZnS量子点荧光猝灭的现象,建立了一种简单快速测定农药甲胺磷的新方法.在最佳实验条件下,CdSe/ZnS量子点的荧光猝灭程度与甲胺磷浓度在4.72×10-7～7.08×10-6 mol/L范围内呈线性关系,相关系数为0.998 8,检出限为2.5×10-7 mol/L.本法已成功用于大米及莴苣叶菜中农药甲胺磷残留的检测,加入回收率在91.7%～106.7%之间.利用紫外-可见光谱及透射电子显微镜技术,探讨了甲胺磷对CdSe/ZnS量子点荧光的猝灭机理.

A simple and rapid method for methamidophos determination was developed based on the fluorescence quenching of CdSe/ZnS quantum dots by methamidophos.Under the optimized conditions,the linear range of CdSe/ZnS QDs fluorescence intensity versus the concentration of methamidophos was 4.72×10-7—7.08×10-6 mol/L,with a correlation coefficient（R） of 0.998 8 and a limit of detection of 2.5×10-7 mol/L.The proposed method has been applied to the determination of methamidophos in rice and lettuce leaves with standard recoveries of 91.7%—106.7%.The fluorescence quenching mechanism was further investigated by using UV-vis absorption spectra and TEM technique.