Highly sensitive near-simultaneous assay of multiple "lean meat agent" residues in swine urine using a disposable electrochemiluminescent immunosensors array.

Abstract Nowadays, β 2 -agonists are abused illegally as “lean meat agents” for food-producing animals, and cause increasing food-safety accidents in some countries. Due to their hazard to the human health, “lean meat agents” are banned in most countries and required to be routinely monitored. We herein report a disposable electrochemiluminescent immunosensors array for near-simultaneous assay of multiple β 2 -agonist residues in swine urine, by using ractopamine and salbutamol as the models. In this investigation, a screen-printed carbon electrodes array was assembled and acted as the substrate of the immunosensors array. Then the immunosensors array was constructed by site-selectively immobilizing the antigens of ractopamine and salbutamol on the working electrodes of array. After the competitive immuno-binding, with the aid of a homemade single-pore-four-throw switch, the electrochemiluminescent signals of the two β 2 -agonists were sequentially detected using a non-array detector. The limits of detection for ractopamine and salbutamol were 8.5 and 17 pg/mL, respectively, which were much lower than those of the most previous reports. Compared with other routine methods based on chromatography and ELISA, this method is more suitable for screening of multiple β 2 -agonists in quantities of samples, owing to its merits of low cost, user-friendliness and high throughput, and shows great promise in food safety and agonist surveillance.