Abstract: In this paper, two haptens of quinclorac(Q), 6-[(3,7-dichloro-8-quinolino-formacyl) amino-hexanoic acid (QC) and 4-[(3,7-dichloro-8-quinolino-formamino)] butanoic acid (QB), were synthesized by using quinclorac and amino-hexanoic acid or amino-butanoic acid as original materials. These two haptens and quinclorac were separately conjugated to bovine serum albumin (BSA) with the modified active ester method. Three coating antigens, Q-OVA, QC-OVA and QB-OVA were also synthesized with the mixed-anhydride method. As a result of the study, three types of antibody (Q-Ab, QC-Ab and QB-Ab) were produced successfully. Their titers were 2×103，1.2×106 and 1.6×106 respectively, while the concentration of coating antigens were 4 ?g·ml-1. Among these antibodies, the QB-Ab was utilized satisfactorily with coating antigen Q-OVA to detect the herbicide with heterogenous assays; and its IC50 was 0.4 mg·L-1, the limit of detection(LOD) was 0.006 mg·L-1. The difference of the titer between the homologous and heterologous combinations was significant in this study. It was indicated that the spacer length of the coating antigen is important for the recognition by antibodies, and the sensitivity of ELISA can be improved remarkably by heterologous reaction.

Key words: Quinclorac, Hapten, Artificial antigen Synthesis, ELISA