Acidity has a def ining role in numerous chemical and biological processes , for example, the activity of enzymes , the assembly of DNA and the solid phase synthesis of biopolymers using acid or basic labile protecting groups . For all these applications, it is important to have a way to predict and control the acidity, which in most of the cases is done by titrating solutions of compounds dissociated in water or organic solvents, and limits the miniaturization of chemical reactions. The miniaturization of the control of the acidity has a similar impact on combinatorial chemistry to Moore's law for microelectronics , allowing the massive multiplexing of chemical reactions. Electrochemical generation of acidity also allows the regulation of the acidity by the Faradaic currents that can be automatized .