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

摘要

The influence of compounds and enzymes that rap or scavene oxygen species on the chemiluminescence (CL) emission generated by the oxidation of pyrogallol with H_2O_2 is investigated. NaN-3 was chosen for trapping singlet oxygen species, superoxide dismutase (SOD) was chosen as a scavenger of ~(centre dot)O_2~- and catalase (CAT) and peroxidase (PER) were chosen as scavengers of H_2O_2. The CL emission with H_2O_2 is limited to the pHrange 10-12 with the peak intensity at pH 11.0. From the investigation, there is evidence that in the presence of PER, the pH of appearance of CL emission is decreased,while simultaneously, the level of emission is increased; this pH shift indicates the effect of PER on the rate of purpurogallin decomposition achieved through complex formation. On the other hard, CAL enhances CL emission without changing the optimum pH, suggesting its contribution to the formation of only oxygen exygen excimers. Superoxide dismutase (SOD), on the contrary, contributes to the extinguishing of CL emission at pH 11.0 thus giving evidence of the contrbution of superoxide ions to the formation of oxygen excimer species. Finally, NaN_3 enhances CL emission, suggesting a synergistic effect on pyrogallol oxidation with CL emission.