RESUMO
The presence of dieldrin and heptachlor residues in cucurbitaceous crops at concentrations exceeding the limits set by the Japanese Food Sanitation Law constitutes a serious problem. To prevent accumulation of these residues in cucurbitaceous crops, development of high-throughput analysis methods for the detection of contaminants in the soil before cultivation is required. This study aimed to develop a model immunoassay using new monoclonal antibodies (MAbs) to quantitatively determine dieldrin and heptachlor contents in their mixtures. Three distinctive MAbs were obtained from mice immunized with the respective immunogens. MAb DrA-04 showed high reactivity toward dieldrin with ca. 20% cross-reactivity toward heptachlors. MAb DrC-02 displayed a similar reactivity toward dieldrin and heptachlors. The specificity and sensitivity of MAbs DrA-04 and DrC-02 were largely unaffected by the composition ratio of heptachlors in a mixture. Six standard mixtures with different dieldrin and heptachlor contents were prepared. Concentrations of dieldrin and heptachlors in standard mixtures, calculated on the basis of an immunoassay with MAbs DrA-04 and DrC-02, were 88.1-125 and 96.2-115% of the theoretical values, respectively, revealing excellent sensitivity and specificity of this assay. The developed method paves the way for a facile and rapid quantitative determination of chlorinated cyclodiene pesticides in soil.
