Ractopamine as an important β-agonist is frequently found in pork to enhance food quality, which is harmful to human health. Thus, it is extremely important to develop an efficient analytical method to detect ractopamine for food safety control. Herein, we develop a kind of electrochemical biosensor using a biochar-supported Cu2+/Cu+ composite as an electrochemical sensing interface for detecting ractopamine. The electrochemical sensor combines the collective advantages of Nafion (enriches ractopamine and effectively shields the interference of negatively charged compounds), biochar (unique three-dimensional porous network structure to increase the contact area), and Cu2+/Cu+ (excellent electrical conductivity to speed up the charge transfer rate), which are beneficial to the accumulation and electrochemical sensing of targets on a Nafion-biochar-supported Cu2+/Cu+ electrode (NBC-GCE). The as-prepared sensor shows a good electrochemical sensing ability, with an ultralow detection limit and high sensitivity (0.041 μM and 416 μA·mM-1·cm-2, respectively), in the 0.1-1.75 μM range. In addition, the stability, repeatability, and anti-interference performance of the modified electrode are also satisfying. Last, its practicability is shown for assaying ractopamine in pork sausages. This research provides an environmentally friendly method to simultaneously treat food waste and achieve ultrasensitive detection of ractopamine in food.
Keywords: Cu2+/Cu+ redox couple; eggshell membrane; electrochemical sensors; food detection; ractopamine.