Development of a competitive array for discriminative determination of amphenicols in egg based on ribosomal protein L16

The amphenicols (chloramphenicol, thiamphenicol and florfenicol) can cause aplastic anaemia and other severe side effects to the consumers, so it is very necessary to inspect their residues in foods of animal origin. However, there has been no paper reporting the use of amphenicols receptor for the determination of their residues, and all the previously reported immunoassays for amphenicols can not differentiate the specific species. In this study, the ribosomal protein L16 of Escherichia coli was first expressed, and its intermolecular interaction mechanisms with the three amphenicols were studied by using molecular docking technique. Then the protein was combined with three enzyme labeled conjugates to develop a direct competitive array on microplate for determination of the three drugs in egg. Due to the use of principal component analysis to analyze the data, this method could discriminate the three drugs in the range of 0.1-10 ng/mL, and the limits of detection for the three drugs were in the range of 0.0002-0.0009 ng/mL. The analysis results for the unknown egg samples were consistent with a liquid chromatography tandem mass spectrometry method, and the method performances were superior to the previous immunoassays for amphenicols. This is the first paper reporting the use of ribosomal protein L16 to develop a competitive array for discriminative determination of amphenicols in food sample.