Development of indirect ELISA for the determination of herbicide picloram residue in paddy soils

After optimizing the concentrations of the goat-anti-rabbit IgG labeled by HRP and polyclonal rabbit-anti-picloram antibodies (PAb), a rapid and sensitive indirect competitive ELISA was established for quantification of herbicide picloram in contaminated paddy soil samples. The results showed that the optimal dilution ratio of PAb and the goat-anti-rabbit IgG were both 1∶ 500. The detection limit for picloram by this method (LOD) was 5 ng·mL-1, and the linear detection range was 0.07~0.7 μg·mL-1. In the recovery assay in paddy soil extract samples, the average recovery rate was 104.11%, and the coefficients of variation were between 3.13%~11.13%, which met the requirements of pesticide residue analysis. No significant interference from the soil matrix was observed.