Abstract: Chemical modification method was employed to synthesize imidacloprid (IMI) hapten. The IMI hapten was then coupled with BSA and OVA to prepare immunogen (IMI-BSA) and coating antigen (IMI-OVA) by EDC method. Optimal coupling ratios between the IMI hapten and the two carrier proteins were eventually achieved. In order to define immunological characteristics of IMI, anti-IMI serum produced by immunized six-week-old Balb/c mice was tested by indirect ELISA and blocking ELISA. Meanwhile, spleen cells of immunized mice were hybridized with mouse myeloma cells by PEG-induced technique. Hybridoma cell strain 3C8 was obtained through positive screening and clonal culture. The experimental results indicated that the cell strain had high antibody titer, good affinity and high specificity. The optimal IMI-OVA concentration and IMI-mAb dilution were defined by square matrix titration. As a result of the above efforts, a blocking ELISA was developed for quantitative detection of IMI based on IMI-mAb with a linear range of 7.48 × 10-6 to 3.24×10-4 mg/mL (R2 = 0.9928) and a LOD of 8.00 × 10-6 mg/mL.

Key words: imidacloprid, monoclonal antibody, residue, enzyme linked immunosorbent assay (ELISA)