As mentioned above, the EPR signal obtained after 3 min of illumination suggests that it primarily originated from either •OH or •OOH species. In order to distinguish whether the signal is induced by pure •OH, •OOH species, we employ a dimethyl sulfoxide (DMSO) scavenger. The DMSO traps mainly the OH -radicals. Here, we use Sol. 1 with the addition of 10 μL of DMSO aimed to scavenge the OH -radicals (Figure ). At the 3 min of illumination, we note comparable signals measured with BMPO and the DMSO (Figure vs Figure ). The similarities in the main features of the spectra suggest that the species responsible for the EPR signal are primarily