Highly sensitive and selective fluorescence probe for Cr3+ ion detection using water-soluble CdSe QDs

A high-performance sensor for Cr3+ ion detection is proposed based on water-soluble CdSe QDs immobilized on the tip of an optical fiber in a sol-gel matrix. The CdSe QDs have many favorable properties, including good water solubility, low cytotoxicity, high quantum yield, and good resistance to photo-bleaching in aqueous solutions. The experimental results show that the fluorescence intensity of the CdSe QDs exhibits a strong quenching effect following interaction with Cr3+ ions. A linear relationship (R-2 = 0.9964) is observed between the relative fluorescence intensity (I-0/I) and the Cr3+ ion concentration for concentrations in the range of 0.1-20 mu M. In addition, the water-soluble CdSe QDs are found to be more sensitive to Cr3+ ions than to other metal ions such as Cu2+, Ce3+, Al3+, La3+, Co2+, Ba2+, Ni2+ and Ag+. In general, the results presented in this study show that the proposed sensor has significant potential for Cr3+ sensing in many environmental and biomedical applications. (C) 2014 Elsevier B.V. All rights reserved.