Rapid Photoluminescence Quenching Based Detection of Cu2+ in Aqueous Medium by CdS Quantum Dots Surface Passivated by Thiourea

Presented here is a simple yet rapid and efficient analytical method for visual as well as spectroscopic method for sensing of trace concentrations of Cu2+ ions in aqueous medium by systematic photoluminescence quenching of a highly water soluble probe made of CdS quantum dots surface modified by thiourea. The salient features of this work describe rapid detection (2 min equilibration time) of Cu2+ ions at wider linear concentration range (0.025 - 10 mg/L) corresponding to a sensitivity of 2.81(mg/L)(-1) and limit of quantification of 47.3 mu g/L, respectively, suitable for Cu2+ sensing in drinking water and ground water. Further, the detection of Cu2+ ion was free from most interfering cations and anions, except for minor interference from Cr3+, Hg2+ and Pb2+. The robustness of our probe for Cu2+ sensing is demonstrated from efficient Cu2+ spike recovery analysis in groundwater and river water samples.