Application of electrochemical and spin trapping techniques in the investigation of hydroxyl radicals Original Research Article

An electrochemical method combined with spin trapping was applied in the determination of hydroxyl radicals. Hydroxyl radicals were generated by the Fenton reagent, i.e. an iron–EDTA complex reacting with H2O2 in the presence of ascorbic acid. The spin trap reagent phenyl-tert-butyl nitrone (PBN) was used to trap the hydroxyl radicals, and the free radical adduct of PBN could be detected by single sweep oscillopolarography, with its second order derivative cathodic wave at −0.52 V vs SCE. The electrochemical behavior of the PBN adduct was investigated by single sweep oscillopolarography and cyclic voltammetry. An electron spin resonance (ESR) experiment was made in order to verify the existence of the PBN spin adduct in the Fenton system. The experimental conditions for the measurement were optimized, and then the scavenging effect of some compounds on hydroxyl radicals was also studied.