关键词: 金霉素, 多克隆抗体, 酶联免疫吸附测定, 胶体金, 免疫层析试纸条

Abstract:

An immunochromatographic strip test was developed to detect chlortetracycline residue in food using immune colloidal gold technique. Chlortetracycline immuno-antigen (CTC-BSA) was prepared by conjugating chlortetracycline to bovine serum albumin via glutaraldehyde, and injected into rabbits to prepare anti-CTC polyclonal antibody. The resulted anti- CTC antibody was purified, and its titer and specificity was determined by indirect enzyme-linked immunosorbent assay (ELISA). Subsequently, colloidal gold particles 15 nm in size were prepared by the method of trisodium citrate reduction. The purified anti-CTC antibody was finally conjugated to colloidal gold particles served as a detection reagent to pack the immunochromatographic (IC) strip. A positive reaction gave a visual color to assess the residue level of CTC. Results suggested that the limit of quantification of CTC was 0.7 μg/mL. Cross-reactivity could not be observed till the concentration of tetracycline was higher than 1 μg/mL. Chlortetracycline content obtained with the IC strips provided a positive correlation with that obtained by HPLC method. Using this method, the analysis of CTC in food could be completed within less than 5 min.

Key words: chlortetracycline, polyclonal antibody, ELISA, colloidal gold, immunochromatographic (IC) strip