ESR evidence for the formation of hydroxyl radicals during the reaction of vanadyl ions with hydrogen peroxide.

Hydroxyl radicals from the reaction of vanadyl ions (VO2+) with hydrogen peroxide (H2O2) in an acidic solution can be detected by an electron spin resonance (ESR) spectroscopy using water-soluble spin-traps, α-(4-pyridyl-1-oxide)-N__-tert-butylnitrone (POBN) and 5, 5-dimethyl-1-pyrroline N__--oxide (DMPO). Further, the fact that some hydroxyl radical scavengers suppressed or reduced the production of POBN-OH adducts affirms the formation of hydroxyl radicals at the initial step of the reaction between VO2+ and H2O2.