Development of enzyme linked immunosorbent assay and lateral flow immunoassay for the rapid detection of dapsone in milk

The excessive use of dapsone (DDS) in food animals could result in its accumulation in humans through the food chain, which in turn endangers human health. A sensitive monoclonal antibody (mAb) against DDS with a half inhibitory concentration (IC50) of 0.586 ng mL(-1) was prepared in this study. Furthermore, a lateral flow immunoassay (LFIA) was established for the detection of DDS based on the anti-DDS mAb. Under optimized conditions, the developed LFIA had outstanding sensitivity with a visual limit of detection (vLOD) and a cut-off value of 1 ng mL(-1) and 20 ng mL(-1) for DDS in milk, respectively, which could be used for semi-quantitative detection of DDS. In milk sample analysis, a red test line on the LFIA strip signified 20 ng mL(-1) DDS. In spiked samples and the recovery test, the results of the LFIA were in agreement with those of ic-ELISA, and the test using the LFIA strip could be completed within 15 minutes. Therefore, the established LFIA method in this study represents a reliable and compelling analysis for the rapid detection of DDS in milk.