▎ 摘　　要

An electrochemical sensor for sensitive detection of ractopamine (RAC) was fabricated by using molecularly imprinted polymer (MIP) incorporation with graphene (GR), ionic liquid (IL) and gold nanoparticle (AuNPs) nanocomposites. The AuNPs-IL-GR nanocomposite was utilized to improve the electrochemical response while MIP served as a recognition element. The MIPs were prepared by electropolymerization of o-phenylenediamine (oPD) on the AuNPs-IL-GR nanocomposite modified electrode. The resulting sensor was studied with respect to its response to hexacyanoferrate as a probe and characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was used to investigate the electrochemical behaviors of the proposed sensor in a phosphate buffer solution. Under optimal conditions, the peak current was linear to RAC concentration in the range from 10 mu g L-1 to 5000 mu g L-1, with a low detection limit of 0.46 mu g L-1 (S/N = 3). The electrochemical MIP-sensor was applied to the determination of RAC in swine urine samples and satisfactory results were obtained.