Enzyme immunoassays for s-triazine herbicides and their application in environmental and food analysis

Seventeen rabbits and forty mice were immunized with immunogens prepared by derivatizing atrazine and simazine and conjugating them via aminohexanecarboxylic acid and thiopropanecarboxylic acid substituents to proteins. Six rabbit antisera and one murine monoclonal antibody were incorporated into the ELISA (enzyme linked immunosorbent assay) format using peroxidase and alkaline phosphatase tracers. Superior antisera for atrazine, simazine and ametryn exhibited in optimized assays a 50% binding inhibition at 0.16, 0.25 and 0.45 μg 1−1, respectively. The IC50 value for the monoclonal antibody to atrazine was about 1.0 μg l−1. The most sensitive antiserum Atr-(CH2)5-OV-3C exhibited 74.1% cross-reactivity with propazine and 26.3% with deethylatrazine. Antisera produced in response to the simazine-S-(CH2)2- determinant showed a remarkable variety in s-triazine recognition selectivity. Antiserum Sim-S-(CH2)2-KLH-C was extremely sensitive to ametryn, terbutryn and prometryn with cross-reactivities based on simazine (= 100%) 2200, 1100 and 1480%, respectively. Structural aspects of these findings are discussed. ELISA for atrazine was evaluated on surface water and ground water samples collected from a contaminated area. The amounts of atrazine found by ELISA were in good agreement with GC-MS analysis. Starting data for the application of ELISA to juice and milk samples are also presented.