Abstract: Objective: Aiming at the development of an immunochromatographic method based on dyed latex beads for the detection of clenbuterol (CLB) in swine urine. Methods: Dyed latex beads were conjugated with anti-CLB antibody and vacuum freeze-dried. CLB-bovine serum albumin (CLB-BSA) conjugate and goat anti-mouse IgG antibodies were coated onto nitrocellulose membranes to establish test and control lines, respectively. The test was carried out by placing swine urine into the sample well and mixed with dyed latex beads. After incubation, the optical density was measured by a microplate reader. Results: After optimizing the physical and chemical parameters, the best surfacant was Tween-20, 300 nm dyed latex beads were chosen, and the incubation time was 9 minutes. The limit of detection (LOD) was 0.013 ng/mL. The recoveries from spiked swine urine varied from 97.8% to 106.0%, with relative standard deviation of less than 9.6%. Conclusion: A sensitive and accurate method for the detection of CLB was successfully developed in this paper.

Key words: immunochromatographic strip, dyed latex beads, clenbuterol, swine urine, quantitative detection