Electrochemical sensor for toxic ractopamine and clenbuterol based on the enhancement effect of graphene oxide

Graphene oxide (GO) and reduced graphene oxide (RGO) were prepared from graphite powder, and then used to modify the surface of glassy carbon electrode. The electrochemical behavior of ractopamine and clenbuterol, illegally used nutrient repartitioning agents, was investigated on different carbon materials surface. Compared with glassy carbon, graphite and RGO, GO exhibited strong enhancement effect and greatly increased the oxidation signal of ractopamine and clenbuterol. The functional groups were analyzed, and a large number of oxygen-containing groups were introduced on surface of GO, which was the main reason for high electrochemical activities. Furthermore, the application of GO in the simultaneous detection of toxic ractopamine and clenbuterol was studied. Based on the enhancement effect of GO, a sensitive, rapid and simple electrochemical method was developed for the simultaneous detection of ractopamine and clenbuterol. The limits of detection were 17 and 15 mu g L-1 for ractopamine and clenbuterol, and the units of sensitivity were 1.22 mu A/mg L-1 and 1.39 mu A/mg L-1. Finally, it was used to detect the content of ractopamine and clenbuterol in pork samples, and the recovery was over the range from 90.1% to 98.6%. 2012 Elsevier B.V. All rights reserved.