ZnSe quantum dots based fluorescence sensors for Cu2+ ions

Water soluble ZnSe quantum dots (QDs) modified by mercaptoacetic acid (MAA) were used as selective copper ions probes by fluorescence spectroscopic technique. The results showed that the fluorescence of the water-soluble ZnSe QDs could be quenched only by Cu2+ in physiological buffer solution. The optimum fluorescence intensity was found to be at pH 7.0 with a temperature of 25 °C. Under these optimum conditions, the detection limit of Cu2+ ions was 4.70 × 10−7 mol L−1. The effect of foreign ions on the fluorescence intensity of ZnSe QDs was also studied and foreign ions showed low interference response in detecting of Cu2+ ions. Moreover, the quenching was discussed to be a static quenching procedure, which was proved by quenching rate constant Kq (2.29 × 1013 L mol−1 s−1).