Rapid Determination of Ractopamine in Porcine Urine by a Fluorescence Immunochromatography Assay

A novel fluorescence immunochromatographic assay is reported for the determination of ractopamine. The protocol was completed within 12 min. The qualitative assay was evaluated based on the intensity of fluorescent microparticles from the test line. The limit of detection was 0.20 mu g/L, the limit of quantitation was 0.39 mu g/L, and the correlation coefficient of dose-response curve was 0.9907. The recoveries were from 86 to 115%, and the coefficient of variation was less than 15%. The cross-reactions with tolterodine tartrate, clenbuterol, cycloclenbuterol hydrochloride, salbutamol, and terbutaline sulfate were less than 0.01%. The fluorescence immunochromatographic assay was faster and more sensitive than the traditional enzyme-linked immunosorbent assay and hence was suitable for ractopamine screening.