Improvement of the stability of immunochromatographic assay for the quantitative detection of clenbuterol in swine urine

Abstract

Clenbuterol is banned as a feed additive in China and in other countries. Lateral-flow immunochromatographic assay can be applied in the quantitative detection of clenbuterol. Our group has previously developed an immunochromatographic assay to detect clenbuterol in swine urine rapidly and quantitatively. This method was based on the ratio of the color intensity of a test line to that of a control line (T/C) to offset the matrix effects of samples and diminish variations among different strips. In this study, the stability of this method was successfully improved and verified by an accelerated aging test that involved storage at 60 °C for three weeks. Results showed that the control line was the main factor affecting the strip stability. To improve the stability of the test strip, we mixed the goat anti-mouse antibody spotted on the control line with WellChampion, Antibody Enhancer, and Protein StabilPLUS. Alterations in the T/C ratio were evaluated using negative and positive swine urine samples. Stability was effectively improved by adding WellChampion. Furthermore, the newly prepared strips showed satisfactory stability by drying the nitrocellulose membrane at 60 °C for one day.