A novel Mn-doped CdTe/ZnS quantum dots was synthesized in aqueous solution with 3-mercaptopropionic acid as the stabilizer, and characterized by atomic force microscopy, ultraviolet-visible spectrometry and spectrofluorimetry, respectively. A new approach was developed for the sensitive and selective detection of mercury ions with Mn-doped CdTe/ZnS quantum dots as phosphorescence probes. Influence factors, including the concentration and pH of buffer, reaction time and quantum dots concentration, were investigated. Under the optimum conditions, the calibration graph was linear in the range from 5.0× 10^－8 to 1.0×10^－5 mol/L of mercury ions concentration, with a detection limit of 4.3×10^－9 mol/L. The proposed method has been successfully used for the determination of trace mercury ions in water sample. The interaction mechanism between mercury ions and quantum dots has been primarily discussed.

Key words: quantum dots, mercury ion, phosphorescence detection, Mn-doped CdTe/ZnS