DEVELOPMENT OF ENZYME-IMMUNOASSAY FOR THE DETECTION OF THE HERBICIDE NORFLURAZON

An enzyme-linked immunoassay (ELISA) was developed for the herbicide norflurazon [4-chloro-5- (methylamino)-2-[3-(trifluoromethyl)phenyl]-3(2H)-pyridazinone]. Antisera were obtained from two rabbits that had been immunized with a conjugate of butyric acid norflurazon [4-chloro-5- (aminobutyric acid)-2-[3-(trifluoromethyl)phenyl]-3(2/f)-pyridazinone] and bovine serum albumin. The metabolite, desmethyl norflurazon [4-chloro-5-(amino)-2-[3-(trifluoromethyl)phenyl]-3(2H)-pyridazinone] was 22 and 48% cross-reactive for rabbit 1 and rabbit 2 antisera, respectively. The experimental herbicide metflurazon [4-chloro-5-(dimethylamino)-2-[3-(trifluoromethyl)phenyl]-3(2H)- pyridazinone] was 37 and 42 % cross-reactive for rabbit 1 and rabbit 2 antisera, respectively. Two other phenylpyridazinone-based compounds, pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone] and 4,5-dichloro-2-phenyl-3(2H)-pyridazinone, were less than 3% cross-reactive for both antisera. The assay was tested with water samples that had been spiked with either norflurazon or one of the abovementioned compounds. The detection limits for norflurazon and desmethyl norflurazon were 1 and 10 ng/mL, respectively. Seven non-phenylpyridazinone-based pesticides were assayed, and none were cross-reactive with either antisera. © 1990, American Chemical Society. All rights reserved.