Relative intensities versus pH for the two different gallate free radical species generated in different pH environments. ▲ corresponds to the species as seen in Figure 1, top spectrum; ● corresponds to the species of Figure 1, bottom spectrum. The relative intensities were obtained by dividing all values by the maximum intensity observed for the respective species. The concentration ratios of the two forms of the gallate radical were very different. The concentration of fully ionized species present at the highest pH (≈13) examined was approximately 1000 times greater than the protonated radical seen at pH ≅ 9.