▎ 摘　　要

In this paper, a facile electrochemical sensor for simultaneous detection of Cd2+ and Pb2+ was fabricated, on the base of in situ growing gold nanoparticles (AuNPs) on L-cysteine functionalized metal-organic frameworks (L-MOFs) and graphene oxide (GO) nanocomposites (L-Au-MOFs-GO). First, L-MOFs were in-situ synthesized on the GO nanosheets by a one-step hydrothermal method. Then, the L-cysteine in L-MOFs-GO nanocomposite was used as a reductant to react with HAuCl4 and in-situ obtain AuNPs, finally forming the L-Au-MOFs-GO composite. This L-Au-MOFs-GO composite not only can enhance the conductivity of the composite by acceler-ating the electron transfer, but also can act as an enrichment medium phase of heavy metal ions because of the interaction between metal cations and hydrophilic groups of L-MOFs or GO. The morphology of L-Au-MOFs-GO composites were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FT-IR), and X-ray diffraction (XRD). The results showed that the electrochemical performance of L-Au-MOFs-GO composite was better than GO material or MOFs-GO composite. Under the optimal conditions, the L-Au-MOFs-GO mod-ified electrode was successfully applied to individually and simultaneously detect the Cd2+ and Pb2+ in an acetic acid buffer solution with good selectivity and high sensitivity. This method was utilized for simultaneous detection of Cd2+ and Pb2+ in river water and the leaching solution of watermelon with great reliability and accuracy. This new nanomaterial for simultaneous detection of Cd2+ and Pb2+ has the potential application in complicated samples.