Influence of oxidant-species scavengers on the chemiluminescence (CL) emission generated during the oxidation of pyrogallol by hydrogen peroxide

The influence of compounds and enzymes that trap or scavenge oxygen species on the chemiluminescence (CL) emission generated by the oxidation of pyrog allol with H2O2 is investigated. NaN3 was chosen for trapping singlet oxyge n species, superoxide dismutase (SOD) was chosen as a scavenger of O-.(26)- and catalase (CAT) and peroxidase (PER) were chosen as scavengers of H2O2 The CL emission with H2O2 is limited to the pH range 10-12 with the peak in tensity at pH 11.0. From the investigation, there is evidence that in the p resence of PER, the pH of appearance of CL emission is decreased, while sim ultaneously, the level of emission is increased; this pH shift indicates th e effect of PER on the rate of purpurogallin decomposition achieved through complex formation. On the other hand, CAT enhances CL emission without cha nging the optimum pH, suggesting its contribution to the formation of only oxygen excimers. Superoxide dismutase (SOD), on the contrary, contributes t o the extinguishing of CL emission at pH 11.0 thus giving evidence of the c ontribution of superoxide ions to the formation of oxygen excimer species. Finally, NaN3 enhances CL emission, suggesting a synergistic effect on pyro gallol oxidation with CL emission. (C) 1999 Elsevier Science B.V. All right s reserved.