Preparation of a multi-hapten antigen and broad specificity polyclonal antibodies for a multiple pesticide immunoassay

A multi-determinant artificial antigen was prepared by haptens of four pesticides (chlorpyrifos, triazophos, carbofuran and parathion methyl) conjugating to the carrier protein BSA in turn. Male New Zealand white rabbits were immunized with this multi-determinant immunogen to produce the polyclonal antibodies (PAbs), which can recognize the four pesticides. The PAbs displayed high level for each relative hapten-OVA conjugate, with the favorable titers of 4.49 × 104, 8.98 × 104, 2.24 × 104 and 1.86 × 104, for CHBu-OVA, THHe-OVA, BFNB-OVA and MP5-OVA, respectively. Characterization studies of the PcAbs showed that it has high affinity and specificity to the four relative pesticides. An indirect competitive ELISA was developed for multi-residue determination. The I50 value for the four pesticides was 0.290, 0.065, 0.582 and 2.824 (mu)g mL^-1, with the detection limit (I10) of 0.022, 0.005, 0.015 and 0.115 (mu)g mL^-1 for carbofuran, triazophos, chlorpyrifos and parathion methyl, respectively. The linear rang was 0.016–2.000, 0.005–0.500, 0.010–2.000 and 0.063–5.000 (mu)g mL^-1, respectively, for carbofuran, triazophos, chlorpyrifos and parathion methyl. Results indicated that, this study provided a new strategy to develop immunoassays through artificial antigen design for pesticides multi-residue determination.