Recently, M. Nguyen and colaborators reported an interesting work where the chemical oxidation of TDMQ20 was carried out in several conditions . According to the autors in the absence of a proper catalyst, the N-oxidation of the tertiary amine was favoured, leading to no significant change of the UV-Vis spectra. When an organometallic catalyst was added to the system, a wide variety of oxidation products were generated, many of them involving the loss of the primary amine attached to the quinolone ring. The generation of these products lead to a significant change of the UV-Vis spectra, wich a remarkable loss of absorbance at 261 nm (maximum of absorption for free TDMQ20) and generating new absorption bands at 241 and 330 nm. All of these observations are in agreement with the spectroelectrochemical results obtained: the first step of electrochemical oxidation leads to the N-oxidation of tertiary amine of TDMQ20, and generated a chemisorbed oxidation product without change in the UV-Vis spectra and passivating the electrode surface.