Development of a Nano-Gold Capillary Immunochromatographic Assay for Rapid and Semi-Quantitative Detection of Clenbuterol Residues

A capillary immunochromatographic assay (CICA) using colloidal gold-labeled monoclonal antibodies was developed for semi-quantitative detection of clenbuterol (CLE) in this paper. This novel system fabricated in a competitive format was supported by glass capillary because of its easily modified, low cost, favorable optical properties. Here, two different-sized gold nanoparticles (13 and 26 nm) were prepared and corresponding assay conditions were optimized. By comparing the results between the two different-sized AuNPs, the 26-nm-AuNPs manifested higher sensitivities which the detection limit was estimated to be 0.35 ng/ml and the cut-off level with the naked eye of 2.5 ng/ml was observed. Using the optimized parameters, the intra-assay and inter-assay coefficients of variation (CVs) were a parts per thousand currency sign10.2 % and the recovery reached 70.8-115.5 % in pig urine, pork, beef, pork sausage and luncheon meat. The performance, including sample preparation, could be accomplished within 24 min. These results suggest that CICA holds promising use for sensitive, simple and low-cost on-site detection of CLE.