Quantum dots based “On-Off” fluorescence probe for the selective detection of Cu2+ ion : Application to real sample analysis

Abstract

Turn ‘On-Off’ quantum dot-based fluorescent probe has been developed for the selective detection of Cu2+. This strategy achieved by consecutively fluorescence enhancement and quenching of mercapto propionic acid (MPA) capped cadmium sulphide quantum dots (MPA-CdS QDs) by the addition of D-penicillamine (D-PA) and Cu2+ respectively. After successive addition of Cu2+in CdS QDs-(D-PA) system, the fluorescence intensity of quantum dots decrease due to the removal of D-PA molecules from the surface of QDs as well as selective ion exchange process takes place between Cu2+ and Cd2+ at the surface of QDs. At optimal conditions, probe offers a good response in the linear range between 4 ng/mL and 40 ng/mL with LOD 2.71 ng/mL. This reported strategy is a very simple and selective towards Cu2+. Hence, a new method for the potential detection of Cu2+ in real pharmaceutical samples can be developed by using QDs-based fluorescence probe.