Electric field dependence of phase equilibria of binary Stockmayer fluid mixtures

Contribution of Eigenmobility Shifts to the Separation of Peptides in Capillary Electrophoresis with Aqueous–Acetonitrile Background Electrolytes

“…To evaluate these effects further, in this study, simulation procedures have been implemented and the findings compared to experimental observations (for further details about the methods employed refer to the theory and computational procedures section in the SI). Interestingly, as discussed below, segregation of the aquo-acetontrile mixtures into partially enriched binary phases appears to occur with all CE experiments undertaken in the current study with an electric field strength of +25 kV.m –1 , which is well below the calculated levels of electric field strength with binary Stockmayer fluid mixtures …”

“…Interestingly, as discussed below, segregation of the aquo-acetontrile mixtures into partially enriched binary phases appears to occur with all CE experiments undertaken in the current study with an electric field strength of +25 kV.m −1 , which is well below the calculated levels of electric field strength with binary Stockmayer fluid mixtures. 32 Eigenmobility and Analyte Peak Broadening with Aqueous Acetonitrile BGEs. In the absence of acetonitrile in the BGE at pH 2.98, the five peptides (their physicochemical properties are listed in Table S1) were separated with good resolution and peak shape (Figure 1A).…”

“…29−31 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. 32 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. Recently, the two-phase behavior of acetonitrile−water mixtures in capillary liquid chromatography has also been reported and confirmed by fluorescence spectroscopy.…”

“…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.…”

Evaluation of the grand-canonical partition function using Expanded Wang-Landau simulations. V. Impact of an electric field on the thermodynamic properties and ideality contours of water

“…However, the response of a polar liquid subjected to very strong fields still remains poorly understood. Recent work show that the critical temperature of water subjected to very large electric fields is lower than that of the bulk 16,17 , while others indicate either the opposite behavior [18][19][20][21] or, in the case of nanoconfined water, a complex dependence of the critical temperature on the extent of the nanoconfinement and the field strength 22 . There are also few studies available on the impact of the electric field on the Gibbs free energy and entropy of water.…”