Kinetic analysis of the Fenton reaction by ESR‐spin trapping

A quantitative analysis of hydroxyl radical (·OH) generated in the Fe2+‐hydrogen peroxide reaction system was explored by a spin‐trapping method using 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO) combined with electron spin resonance spectroscopy. Based on the numerical analysis of Fenton‐related reactions, the reduction of DMPO‐OH adduct from 1…n1 stoichiometry prominent at high concentrations of Fe2+ was consistent with a reaction model in which a molar amount of hydrogen peroxide was reduced by two molar amounts of Fe2+. Furthermore, time‐dependent decrease in DMPO‐OH quantity, apparent at much higher concentration of Fe2+, was proved due to the reaction not with Fe2+ but with Fe3+.