Carboxyl retained hapten of quinclorac produces highly sensitive antibody and immunochromatographic assay

In order to obtain better anti-quinclorac antibody, we synthesized three novel quinclorac haptens de novo, including a hapten (H3) retains the carboxyl. As expected, H3 immunized mice showed the best immune responses and generated the anti-quinclorac monoclonal antibody (mAb 6D2F4) with the 50 % inhibition concentration (IC50) of 1.63 ng mL−1 in indirect competitive enzyme-linked immunosorbent assay, which is improved 30- to 245-fold than the reported anti-quinclorac antibodies, and no significant cross-reactivities with the analogues of quinclorac. Then mAb 6D2F4 was employed to develop the colloidal gold immunochromatographic assay (GICA) for the detection of quinclorac. The limit of detection (LOD) of naked eye observation is 8 ng mL−1, while the LODs of GICA in agro-products samples also can meet the requirements regulated by China. Besides, the detection results of blind samples by GICA show high consistency with those by high performance liquid chromatography analysis.