Diethyldithiocarbamate functionalized CdSe/CdS quantum dots as a fluorescent probe for copper ion detection.

Abstract A new fluorescent probe for copper ion detection is reported that it is based on the quenching of the fluorescence of the diethyldithiocarbamate (DDTC)-functionalized quantum dots (QDs) in the presence of copper ions. DDTC was bound to the QDs via the surface ligand exchange to form DDTC–QDs conjugates following the capping of 2-mercaptoacetic acid on the core–shell CdSe/CdS QDs. It was found that the fluorescence intensity of the conjugates was quenched after coordinated with Cu 2+ . A linear relationship existed between the extent of quenching and the concentration of copper in the range of 0–100 μg L −1 , with a detection limit of 0.29 μg L −1 (3 σ ). The DDTC-functionalized QDs showed excellent selectivity for Cu 2+ over other metal cations. The fluorescent probe was successfully used for the determination of copper in environmental samples.