Synthesis of artificial antigen and studied on influence factors of ELISA for chlorothalonil residue

In this work, the chlorothalonil derivative (i.e. hapten) was synthesized. The chlorothalonil artificial antigens were prepared via the hapten conjugated with carrier proteins by activated-ester and mixed-anhydride method, respectively. The antiserum were obtained through immunizing the New Zealand white rabbits with the immune antigen, and the appropriate concentrations of coating antigen and antibody of ELISA were determined with chessboard format. Meanwhile, the influence factors of washing processes were also investigated, which evaluated by the value of OD₄₉₀. The results showed that the artificial antigens of chlorothalonil were successfully synthesized, and the antiserum titer was about 1:1.0×10⁴. The detection limit (IC₂₀) of ELISA was 0.0123ng/mL. The recoveries of ELISA were from 84.0% to 89.8%, Coefficient of variation ranged from 3.0% to 7.6%. And all the Cross-reactivity (CR) with chlorothalonil analogous structure compounds were less than 0.01%.