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To produce high-affinity monoclonal antibodies against pesticide imidacloprid, we synthesized the haptens 1-[(6-Carboxylethylthio-3-pyridinyl) methyl] -N-nitro-imidazolidinimine (named as H1) and 1-[(6-Chloro-3-pyridinyl) methyl]-3-carboxylpropyl-N-nitro-2-imidazolidinimine (termed as H2). And then the haptens were coupled to bovine serum albumin (BSA) and ovalbumin (OVA) for immunogen (H1-BSA) and coating antigen (H2-OVA) respectively by NHS ester method. BALB/c mice were immunized with H1-BSA conjugate. We obtained two hybridoma cell lines 2F11/A9 and 2G6/G12 secreting antibody specific for imidacloprid from the conventional hybridoma technology. The result showed that the subtypes of obtained monoclonal antibodies were IgG3 and IgG1, respectively, and the titers of ascites were up to 1:128 000. The indirect competitive ELISA indicated the IC50 values of 5.3 and 28.3 ng/mL with detection limits of 1.1 ng/mL and 7.7 ng/mL, respectively. Two monoclonal antibodies had no apparent cross reactivity with six analogous compounds. Thus, two prepared monoclonal antibodies had a very high affinity and specificity, and it could be used to develop ELISA for rapid determination of imidacloprid residue and laid a solid foundation for research and development of products for immunoassay.

The purified anti-carbofuran antibody was conjugated to carbonyl diimidazole (CDI)-activated Sepharose CL-4B to synthesize the immunosorbent for the immunoaffinity chromatographic (IAC) column specific to carbofuran. The conditions of IAC were optimized as follows: pH 7.2 phosphate buffer (PB) was used as equilibrium and adsorbent medium, and methanol-water (60:40, v/v) as eluent. The results showed that the dynamic column capacity was up to 1.58 mg/L bed volume. The efficiency of enrichment of IAC was more than 167 times when the initial concentration of carbofuran in a standard sample solution was lower than 2 microg/L. The spiked river water was cleaned up and enriched by IAC, and carbofuran in eluate was determined by enzyme linked immunosorbent assay (ELISA). The average recovery of carbofuran from river water was 89.8% with the relative standard deviation of 4.8% at the spiked level of 0.1 mg/L. Meanwhile the eluate was determined by high performance liquid chromatography (HPLC), the results from HPLC correlated well with those from ELISA. The IAC method of carbofuran was successfully established.

In order to synthesize the artificial antigen methylparathion(M1605), methylparathion was reduced into amino-methylparathion by using acetic acid-zinc powder-hydrochloric acid. Artificial antigens (M1605-BSA, M1605-TTH) were synthesized by conjugating amino-methylparathion to bovine serum albumin(BSA) and tachypleus tridentatus hemocyanin (TTH) directly after diazotization. Rabbits were immunized with M1605-BSA for 10 weeks, and the high titer and high specificity antiserum from those rabbits was testified by double agar gel diffusion and indirect ELISA. The results showed that an artificial antigen was obtained successfully and this made it possible to establish the immunoassay of M1605.