Electrochemical pH Modulation via Quinone Derivatives

Example 22

Reversible electrochemical oxidation/reduction of pH modulation reagents such as quinone derivatives, hydrazine derivatives, or water have been demonstrated for a rapid pH change in a local region (Fomina et al., Lab Chip 16, pp. 2236-2244 (2016)). The pH modulation limit can depend on the pKa and oxidation/reduction potential of the specific pH modulation reagents, and their concentration. On-demand pH modulation by the oxidation of 2,5-dimethyl-1,4-hydroquinone and the reduction of the 2,5-dimethyl-1,4-benzoquinone on an indium-tin oxide electrode in 1 mM phosphate buffer was tested. FIG. 53 shows that when anodic current is applied to the electrode, the proton production overcomes the buffer capacity and pH of the solution becomes more acidic and vice versa.