Determination of quinoxaline antibiotics in fish feed by enzyme-linked immunosorbent assay using a monoclonal antibody
Olaquindox (OLA), mequindox (MEQ), and quincetone (QCT) are widely used synthetic antibiotics of the quinoxaline-1,4-dioxide family. However, no studies have focused on the detection of sum of OLA, MEQ, and QCT by mAb-based enzyme-linked immunosorbent assay (ELISA). In this study, a specific mAb 2F3 against OLA, MEQ, and QCT was successfully prepared. Furthermore, using the mAb 2F3, an indirect competitive ELISA (icELISA) was developed using MQCA (quinoxaline marker) coupled to OVA as the heterologous coating antigen. Under optimized assay conditions, the IC50 values were 1.03, 1.54, and 1.73 ng ml−1 for OLA, MEQ, and QCT, respectively. The recoveries ranged from 82.1% to 96.3%, and no cross-reactivity with other compounds was detected except for carbadox (0.9%). The developed icELISA was rapid and reliable for the determination of sum of OLA, MEQ, and QCT in fish feed.