Metabolism and dissipation kinetics of a novel protoporphyrinogen IX oxidase herbicide [oxadiargyl] in various buffered aqueous system under laboratory-simulated condition

Present investigation was carried out using two commercial products Raft (oxadiargyl 6 % EC) and Topstar (oxadiargyl 80 % WP) of Oxadiargyl {5-tert-butyl-3[2,4-dichloro-5-(prop-2-ynyloxy)phenyl]-1,3,4-oxadiazol-2 (3H)-one} to investigate the persistence behavior and metabolism of the herbicide in various aqueous system under different pH condition. Half-life values revealed that alkaline hydrolysis played a dominant role in hydrolytic degradation of this compound. Q-ToF micromass study with the alkaline fractions of oxadiargyl indicated the formation of five metabolites, which was further characterized from their mass fragmentation data. The nature of metabolites formed indicated that heterocyclic oxadiazoline ring cleavage was found to be the main pathway of hydrolytic transformation of oxadiargyl.