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

An electrochemical method combined with spin trapping was applied in the de termination of hydroxyl radicals. Hydroxyl radicals were generated by the F enton 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) wa s used to trap the hydroxyl radicals, and the free radical adduct of PEN co uld be detected by single sweep oscillopolarography, with its second order derivative cathodic wave at -0.52 V vs SCE. The electrochemical behavior of the PEN adduct was investigated by single sweep oscillopolarography and cy clic voltammetry. An electron spin resonance (ESR) experiment was made in o rder to verify the existence of the PEN spin adduct in the Fenton system. T he experimental conditions for the measurement were optimized, and then the scavenging effect of some compounds on hydroxyl radicals was also studied. (C) 1999 Elsevier Science B.V. All rights reserved.