Design of a Fluorescein Capped CdSe Quantum Dots Based Nanosensor for the Selective Detection of Pb2+ Ions in Aqueous Solutions

A novel nanosensor based on CdSe quantum dots was developed for the detection of lead ions in aqueous solution. Synthesized nanosensor exhibited high selectivity and sensitivity for the detection of lead ions at very low concentration. Fluorescence emission of nanosensor was increased linearly within 0-500 μM concentration of Pb2+ ions. In order to synthesize nanosensor, the thioglycolic acid capped CdSe quantum dots were synthesized using Cd2+ and freshly prepared Se2- ions in the presence of thioglycolic acid, which then functionalized with ethylene diamine using EDC/NHS coupling reagent, and then reacting with fluorescein methyl ester. The structure of prepared nanosensor was characterized and confirmed using UV-Vis, Ft-IR, SEM, TEM and EDX analysis.