DOES 3,5,DIBROMO-4-NITROSOBENZENE SULFONATE SPIN TRAP SUPEROXIDE RADICALS

Pulse radiolysis studies show that the spin trap 3,5,dibromo-4-nitrosobenzene sulphonate (I) reacts rapidly with O2•- but the product formed is very unstable. No radicals were detected in ESR studies of solutions of I after reaction with O2•- formed by γ-radiolysis. Evidence is presented that the stable radical observed by some, but not all workers, following exposure of I to the O2•--generating xanthine/xanthine oxidase system, is produced by a peroxidatic oxidation using hydrogen peroxide formed by O2•- dismutation and that formation of this radical depends on the presence of peroxidase activity in the xanthine oxidase sample employed. © 1990.