MECHANISM OF PYROGALLOL AUTOXIDATION AND DETERMINATION OF SUPEROXIDE-DISMUTASE ENZYME-ACTIVITY

The autoxidation of pyrogallol was investigated in the presence of EDT A 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 substan ce and can be detected by electroanalytical methods. The focus here wa s putted on the effect of pH on the autoxidation rate of some intermed iate products produced in pyrogallol autoxidation, which gives sensiti ve second-order derivative cathodic waves at -0.20, -0.96 and -1.45 V vs. SCE, respectively. Reaction mechanism was discussed. The paper als o presented a convenient electroanalytical assay for superoxide dismut ase enzyme activity. (C) 1998 Elsevier Science S.A.