ZnSe quantum dots based fluorescence quenching method for determination of paeoniflorin

Water soluble ZnSe quantum dots (QDs) modified by mercaptoacetic acid (MAA) were used to determinate paeoniflorin in aqueous solutions by the fluorescence spectroscopic technique. The results showed that the fluorescence of the modified ZnSe QDs could be quenched by paeoniflorin effectively in physiological buffer solution. The optimum fluorescence intensity was found to be at incubation time 10 min, pH 7.0 and temperature 25 °C. Under the optimal conditions, the detection limit of paeoniflorin was 7.30×10−7 mol L−1. Moreover, the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant Kq (1.02×1013 L mol−1 s−1).