Mechanism of pyrogallol autoxidation and determination of superoxide dismutase enzyme activity

The autoxidation of pyrogallol was investigated in the presence of EDTA or DETAPAC (diethylenetriaminepentaacetic acid) in the pH range 7.87 to 9.10. Pyrogallol reacts with dioxygen in weakly alkaline solutions to form several intermediate products which are electroactive substance and can be detected by electroanalytical methods. The focus here was putted on the effect of pH on the autoxidation rate of some intermediate products produced in pyrogallol autoxidation, which gives sensitive second-order derivative cathodic waves at −0.20, −0.96 and −1.45 V vs. SCE, respectively. Reaction mechanism was discussed. The paper also presented a convenient electroanalytical assay for superoxide dismutase enzyme activity.