Turn-on fluorescence probe for high sensitive and selective detection of Ag+ by L-glutathione capped CdTe quantum dots in aqueous medium

L-Glutathione (GSH) capped CdTe quantum dots (QDs) (GSH@CdTe QDs) have been successfully synthesized. GSH@CdTe QDs could selectively detect Ag+ by fluorescence emission spectrometry in aqueous medium. The fluorescence intensity of GSH@CdTe QDs linearly increased upon increasing concentrations of Ag+. The detecting limit of Ag+ was found to be 1.3 nM calculated from the linear concentration range of 0.02-0.2 μM. The other foreign mental ions displayed no significant response revealing good selectivity of the sensors towards Ag+. The experimental results indicated the GSH@CdTe QDs were well applied as fluorescence sensor to detect Ag+ in aqueous with high sensitivity and selectivity. Furthermore, it was found that the enhancement of fluorescence intensity arose from the formation of Ag2Te which modified the surface traps on GSH@CdTe QDs.