Monoclonal antibody production and quantum dots lateral flow immunoassay for florfenicol detection

Florfenicol is a broad-spectrum antibiotic commonly used in livestock and poultry. However, its embryotoxicity and hematotoxicity are widely concerned. In this study, a monoclonal antibody (mAb) with high specificity to florfenicol was generated. A highly sensitive and specific quantum dots lateral flow immunoassay (QDs-LFIA) was established, which can qualitatively or quantitatively detect the residual amount of florfenicol in food. The optimal method parameters were determined by optimizing the activated pH, mAb diluents, mAb dosage, probe amount and standard diluents. The visual limit of detection (vLOD) and the instrumental limit of detection (LOD) for florfenicol in QDs-LFIA were 3.2 and 0.02 ng mL−1, respectively. The detection time for the test strip is 6 min. The cross reactivities (CRs) with common structurally similar compounds were below 1.6%. The average recovery rates for pork, eggs, and milk were 90.53% to 114.9%. The sample pretreatment method is simple, fast, and takes no more than 30 min. A comparison between the QDs-LFIA and ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) exhibited a high level of agreement. This approach can meet the needs of specific, rapid, and visual detection of florfenicol in the field. Homology modeling and molecular docking were used to explore the main forces and key amino acids between the antibody and florfenicol, as well as structurally similar compounds. These results contribute to the understanding of the antigen-antibody binding mechanism.