Ultrasensitive detection of trace amount of clenbuterol residue in swine urine utilizing an electrochemiluminescent immunosensor

As a familiar β2-agonist, clenbuterol (CLB) was frequently reported to be illegally abused as a “lean meat agent” for livestock breeding, since it could improve growth rate and inhibit fat synthesis. Due to its potential hazard to human health, it has been forbidden as growth promoter for food-producing animal feeding in most countries. Therefore, the routine monitoring of CLB abuse is exceedingly necessary for food safety purpose. We herein report an ultrasensitive electrochemiluminescent immunosensor, which is firstly applied for assay of trace amount of CLB residue in swine urine. In this investigation, gold nanoparticles doped chitosan composite film was utilized for antigen immobilization, and Ru(bpy)32+-labeled antibody was utilized as the tracer antibody. With a competitive immunoassay format, good analytical performance was obtained. The proposed method shows a linear range of 0.010–1.0 ng/mL, with a limit of detection of 0.0050 ng/mL for CLB, which is evidently lower than that of most previous reports. This method is suitable for screening of trace amount of CLB residue, due to its simple manipulation, short assay time, and high detection sensitivity, and exhibits great promise in food safety and agonist monitoring.