Determination Of Chloramphenicol Residues By Biotin Amplified Immunoassay

In this paper, a sensitive biotin-streptavidin amplified enzyme-linked immunosorbent assay (BA-ELISA) method was developed for the determination of chloramphenicol (CAP) residues. The biotin-streptavidin system was applied to enhance the sensitivity. Two formats of BA-ELISA method were studied. The IC50value and limit of detection (LOD, calculated as IC15) of the indirect BA-ELISA for CAP were the method allowed CAP determination with value of0.46±0.05μg/L and0.05±0.01μg/L, respectively. The variation coefficients of intra-assay and inter-assay were all below19.7%. For the direct BA-ELISA method, the biotinylated antibodies was prepared, and the method allowed the CAP determination with IC50value of0.37±0.04μg/L and a limit of detection of0.03±0.006ug/L. The variation coefficients of intra-assay and inter-assay were all below14.0%. After comparison of the two methods for the limit of detection, sensitivity, and CVs, the direct BA-ELISA was chosen for the detection of CAP in the after work.A series of animal-derived food samples such as milk, pork muscle and fish were analyzed by the direct BA-ELISA method. The effects of different matrices on the ELISA were evaluated, and the matrix interference removal methods and the simple sample extraction procedures were studied. The average recoveries for CAP from fortified samples were in the ranges86%-110%. The assay could satisfy the need of fast screening of CAP residues. In order to validate the accuracy of the direct BA-ELISA, the fortified samples were analyzed by high-performance liquid chromatography (HPLC), and the correlation of results obtained by both methods was very well (R2=0.9706).