CAPILLARY ENZYME-IMMUNOASSAY WITH ELECTROCHEMICAL DETECTION FOR THE DETERMINATION OF ATRAZINE IN WATER

A capillary enzyme immunoassay with electrochemical detection has been developed for the determination of atrazine in water. The assay is ba sed on competitive binding between atrazine and alkaline phosphatase-l abeled atrazine for a limited number of antibody binding sites. The an tibody is attached covalently to a modified capillary surface. The enz ymatic product (p-aminophenol) is detected by amperometric now injecti on analysis. The calibration curve for atrazine has a Linear range of 0.10-10.0 mu g/L and a detection limit of 0.10 mu g/L. An assay includ ing six standards can be done in less than 60 min. Intra- and inter-as say precisions at 0.1 and 5.0 mu g/L are 9 and 8% and 6 and 10%, respe ctively. Recoveries of added atrazine from commercial bottled water, t ap water, and Ohio River water at 0.50 and 5.0 mu g/L range from 100 t o 115%. Simple filtration is the only step needed for sample cleanup.