Analysis of Atrazine Residues in Food by an Enzyme Immunoassay

The application and validation of a highly sensitive and relatively selective enzyme immunoassay (EIA) for the analysis of atrazine residues in food is described. The assay is performed on microtiter plates. The range of detection for atrazine analysis lies between approximately 1 ng/L and 10 µg/L. Various foods in liquid form such as milk, fruit juices, and vegetable juices and in solid form such as corn were analyzed with the EIA in their natural states and after the samples were spiked with defined amounts of atrazine. The solid food samples had to be extracted before EIA analysis. However, the assay did not require concentration or cleanup steps for any of the liquid foodstuffs analyzed. A comparison with HPLC measurements was made with the extracted food samples. A close correspondence was found between the results of the EIA and HPLC measurements, although the extraction yield proved to be relatively low (between 20 and 50%). In the case of the liquid forms, highly accurate measurements of the actual concentrations were obtained with the EIA.