Determination of Ractopamine in Pork Using CuNPs/PAA/GR Nanocomposites Modified Glassy Carbon Electrode

KeyWord:graphene£¨GR£©  ractopamine£¨RAC£©  copper nanoparticles£¨CuNPs£©  chronocoulometry  differential pulse voltammetry£¨DPV£©

Abstract:

      A moderate and simple in-situ growth approach was adpoted to bond coppernanoparticles noncovalently to graphene for preparation of CuNPs/PAA/GR nanocomposites which were used for electrocatalysis of ractopamine£¨RAC£©.The morphology of the material was observed by scanning electron microscopy£¨SEM£©,and the state of the modified glassy carbon electrode was investigated by electrochemical impedance£¨EIS£©.Tests at various scan rates and pH conditions indicated that the modified electrode has an adsorption-controlled electrochemical system.The mechanism for the electrode reaction for ractopamine involves a two-electron transter process accompanied by a deprotonation step.Electrochemical parameters were calculated as follows:the electron transfer number£¨n£© was 1.7,the effective area for the CuNPs/PAA/GR/GCE electrode was 3.57 cm2,12.6 times as large as bare electrode,and the adsorption capacity£¨§¤s£© value was 1.98¡Á10-12 mol/cm2.Under the optimal conditions by differential pulse voltammetric measurement,the calibration curve of RAC was linear in the range of 1-30 ¦Ìmol/L£¨r2=0.990 2£© with a detection limit£¨S/N=3£© of 18.3 nmol/L.With advantages of facile fabrication,high sensitivity,good stability and high reproducibility,the sensor was applied in the detection of ractopamine in pork samples with recoveries of 97.0%-102.5% and relative standard deviations£¨RSD£© of 2.8%-3.2%.