DEVELOPMENT OF AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR THE DETECTIONOF METOSULAM

A direct enzyme-linked immunosorbent assay (ELISA) was developed to qu antitate the herbicide metosulam hoxy-1,2,4-triazolo(1,5a)pyrimidine-2 -sulfonamide) in soil and water. The ELISA had a detection limit of 0. 3 ng.mL(-1), a linear working range of 0.5 ng.mL(-1) to 10 ng.mL(-1), and an IC50 value of 2.8 ng.mL(-1). The metosulam antisera cross-react ed with 5-OH and 7-OH metosulam hoxy-1,2,4-triazolo[1,5-a]pyrimidine-2 -sulfonamide and oxy-1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonamide, re spectively) and the manufacturing intermediate XDE-564 ro[1,2,4]triazo lo[1,5-c]pyrimidine-2-sulfonamide). The assay was used to estimate, ac curately and precisely, metosulam concentrations in soil and water sam ples. Water samples were analyzed directly while soil sample analysis required solvent extraction and dilution prior to analysis. Extraction efficiency was 95%. The ELISA estimations in water correlated well wi th those from HPLC analysis (r(2) = 0.99; slope = 0.99), making the EL ISA a cheap and reliable alternative to conventional residue analysis techniques for quantification of metosulam.