DEVELOPMENT OF AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR IMAZAQUIN HERBICIDE

A sensitive immunoassay system was developed for the quantitation of imazaquin, the active ingredient for SCEPTER herbicide. The assay required a polyclonal antibody generated by immunizing rabbits with a bovine serum albumin conjugate of 5-(2-formylvinyl)-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)benzoic acid. A competitive ELISA system employing horseradish peroxidase conjugated 6-isothiocyanatoimazaquin as a competing molecule was shown to be best for the quantitation of imazaquin. Tetramethylbenzidine was the color-developing substrate. A linear dose-response between 0.4 and 25 ng/mL imazaquin was demonstrated using the above reagents. Linear dose-response was also demonstrated for imazapyr (active ingredient for ARSENAL), imazethapyr (active ingredient for PURSUIT), and imazamethabenz methyl (active ingredient for ASSERT). The antibody was shown to be specific for the imidazolinone class of compounds; no response was observed with non-imidazolinone agrochemicals as well as some metabolites of imazaquin.