Graphene nanosheets(GNs), which were prepared by liquid-phase exfoliation method, were directly casted onto the surface of a glassy carbon electrode to obtain a graphene-modified electrode(GN/GCE). Then, the polypyrimidine/graphene composite film modified electrode(p AMP/GN/GCE) was fabricated by electrodeposition method. The surface morphology of the modified electrode was characterized by scanning electron microscope. Electrochemcial behaviors of sunset yellow(SY) and tartrazine(TT) on p AMP/GN/GCE were i...