As shown in Figure , a longer OCV duration leads to less formation of DHAQ from the dimer. Whereas over 95% of DHA is converted to DHAQ with a zero OCV duration, the conversion efficiency drops to 76% with 16 hours of OCV duration. This adverse effect is more pronounced at elevated OH - concentration, where the conversion efficiency drops to 43% with 16 hours of OCV duration. This suggests that the dimer decomposes more rapidly with increasing OH -concentration. To minimize its decomposition, the dimer should be converted to DHAQ as soon as the dimer forms. Figure also shows that even with zero OCV duration, the conversion of DHA to DHAQ is incomplete and lower in 2.0 M OH - than in 1.0 M OH -. This observation suggests that the decomposition of dimer can be limited but not entirely prevented because of its fast decomposition rate. Note that we cannot exclude the possibility of other decomposition reactions that may occur during the oxidation of DHA. However, no decomposition products were observed using NMR. In Figure , another electrochemical reaction takes place at around 0.45 V; however, the origin of the reaction is still unclear.