Computational epitope engineering of flurodifen and haptens for ultrasensitive immunoassay development

Flurodifen (Flu), a widely used but potentially hazardous herbicide, demands a rapid and efficient detection method for real-time monitoring to mitigate health risks. In this study, the electrostatic characteristics of haptens and Flu were systematically analyzed using a computer-aided technology. High-performance Flu monoclonal antibody (mAb) 2A4 (IC₅₀ = 0.62 ng/mL) was successfully prepared based on anti-mechanism interference effects. The visual detection limit (vLOD) of colloidal gold immunochromatographic test strip (CGIA) to detect Flu for cucumber, cabbage, wheat, and corn samples were 5, 5, 10, and 10 ng/g. Recovery rate was 90.0-98.0 %, and the coefficient of variation (CV) was 1.39-9.43 %. Validation results of positive samples detected by LC-MS/MS method established in this study demonstrated the high accuracy of the CGIA method, it provided visual detection results within 15-20 min, offering an efficient tool to implement timely interventions and mitigate the effects of pollution events.