Abstract:To develop colloidal gold immunochromatographic technique for the rapid detection of Clenbuterol (CL), colloidal gold was prepared by reduction of HAuCl4 using trisodium citrate. Anti-CL monoclonal antibodies (MAb) were then labeled with colloidal gold to obtain colloidal gold labeled MAb. The CL-human serum albumin (HSA) and goat anti-mouse IgG were immobilized on the lateral flow membrane to construct the strip. To obtain the best performance of the strip, several conditions were optimized as follows: the diameter of the colloidal gold particle 15 nm, the amount of MAb for labeling 20 ?g/mL, the pH value 7.4, the conjugate treating buffer 0.05 mol/L phosphate buffer (pH 7.4) containing 0.1% bovine serum albumin (BSA) and the thickness of colloidal gold-labeled CL antibody in use 50 ?L/cm2. In addition, the antigen and goat anti-mouse IgG were coated at 0.5 mg/mL and 2 mg/mL respectively. Under the optimum conditions, the limit of detection (LOD) of the strip was 3 ng/mL for swine urine. Cross-reaction tests showed that negligible cross-reactivity of the strip with six ?-Agonist compounds including ractopamine, salbutamol, etc. was detected. Forty-two samples of swine urine were detected by the developed strip and the results were confirmed by enzyme-linked immunosorbent assay (ELISA) kit. The accordance rate of the two methods was 100 %. The determination of CL by the strip did not need any instruments, and the total time for the determination of one sample was only 5 minutes. This method was applicable for the rapid determination of CL in the field.
