摘要

A facile strategy for detecting xanthine in serum samples by copper nanocluster (CuNCs) with high intrinsic peroxidase-like activity was reported. Firstly, a simple, mild and time-saving method for preparing CuNCs was developed, in which dithiothreitol (DTT) and bovine serum albumin (BSA) were used as reductant and stabilizer, respectively. The as-prepared CuNCs exhibited a fluorescence emission at 590 nm with a quantum yield (QY) of approximately 5.29%, the fluorescence intensity of the as-prepared CuNCs exhibited no considerable change when stored under ambient condition with the lifetime is 1.75 mu s. Moreover, the as-prepared CuNCs exhibited high intrinsic peroxidase-like activity with lower K-m (K-m = 8.90 x 10(-6) mol L-1) for H2O2, which indicated that CuNCs have a higher affinity for H2O2. Compared with natural enzyme, the as-synthesized CuNCs are more catalytic stable over a wide range of pH (4.0+/-13.0) and temperature (4+/-80 degrees C). Finally, an indirect method for sensing xanthine was established because xanthine oxidase can catalyse the oxidation of xanthine to produce H2O2. Xanthine could be detected as low as 3.8 x 10(-7) mol L-1 with a linear range from 5.0 x 10(-7) to 1.0 x 10(-4) mol L-1. These results proved that the proposed method is sensitive and accurate and could be successfully applied to the determination of xanthine in the serum sample with satisfaction.