“…Various effects on CE separations have been investigated, such as changes in resolution and selectivity, , the impact on the EOF or pH of the BGE, as well as the p K a of the ions in the system, ,− when the acetonitrile content in the BGE is changed. As acetonitrile is an aprotic solvent, it is more likely to form solvent clusters in water rather than form an extended hydrogen bonded network. − This property results in acetonitrile/water mixtures behaving experimentally like two (or more) phases under certain conditions. − Moreover, recent theoretical studies on the electric field dependence of phase equilibria of binary Stockmayer fluid mixtures have confirmed that two phase behavior can be induced upon exposure to sufficiently high electric field strengths, e.g., even up to 5 × 10 6 Vm –1 , with the shapes of the vaporization and condensation curves changing, and the disappearance of the critical point and appearance of an azeotropic point . Under such conditions, the constituent molecules of a binary fluid mixture can separate into two partially miscible fluid phases, one of which is enriched with the more polar molecules.…”