Electrolyte solutions asymmetry

Spherical micelles or globular proteins in solution can be considered as an asymmetric electrolyte solution where the ionic species grossly differ in charge and size. Taking into account these asymmetries, an extension of WOZ equa-... 

The electrolyte concentration in the separation electrolyte solution should be higher than that of the sample to avoid local potential gradients, which give uneven migration and zone asymmetry. 

With pH electrodes, one expects the cell potential to be near zero at pH 7. The two reference elements in the cell exhibit an asymmetry with respect to the chloride concentration in the contacting electrolyte solutions the outer reference element is typically in contact with 3 M KCl, while the inner electrolyte contains on the order of tens of millimolar of chloride salt. Not considering the junction potential, one may write for the ideal cell potential ... 

It has become fairly common to adopt the manufacture of combinations of internal reference electrode and its inner electrolyte such that the (inner) potential at the glass electrode lead matches the (outer) potential at the external reference electrode if the glass electrode has been placed in an aqueous solution of pH 7. In fact, each pH glass electrode (single or combined) has its own iso-pH value or isotherm intersection point ideally it equals 0 mV at pH 7 0.5 according to a DIN standard, as is shown in Fig. 2.11 the asymmetry potential can be easily eliminated by calibration with a pH 7.00 0.02 (at 25° C) buffer solution. 

If the solution of electrolyte is not infinitely dilute, the ion is retarded in its motion because of the electrical attraction between ions of opposite sign (asymmetry effect), and because the positive and negative ions are moving in opposite directions each carrying some solvent (electrophoretic effect). Both of these effects are intensified as the concentration of the electrolyte increases so that the retarding forces increase and the conductivity decreases. 

It is generally acknowledged that electric fields play a dominant role in cellular chemical actions. Such electric fields arise due to the presence of membranes that separate internal cell electrolytes from external bathing solutions. Differing double layer potentials are established on both sides of the membrane membrane asymmetries set up ionic charge separation potentials membrane components set up concentration difference potentials last, but not least, externally applied fields can be used to modify cellular potentials. 

For aqueous electrolytes as sample (100 to 180 mM NaCl, 4.25 mM KCl, 0.625 mM MgCb, 1.10 mM CaCb) and an aqueous reference solution (140 mM NaCl, 4.25 mM KCl, 0.625 mM MgCh, 1.10 mM CaCb) the results in Table 1 were obtained by applying equation (4). In all the experiments, the slope of the electrode response is very close to the theoretical value (equation (3)). The standard deviation of the individual readings from the regression line is surprisingly small (average 0.06 mV) and is well below the tolerated values of 0.12 mV for Na. Since the induction of asymmetry in membranes due to proteins can be avoided or... 

The first published simulation of solution properties of substantial size and charge asymmetric electrolytes was made over 20 years ago and was restricted to low charge asymmetry, Zr = 12 [103]. Despite much improved computer resources, later simulation studies were still bounded by an upper charge asymmetry Unfit of Zr 20 [21,58,74,104-108). It was first with the... 

Movement of ions through a solution is induced by the imposition of an electric field - a consequence of the applied potential between the electrodes. The electric field force experienced by an ion causes it to accelerate. This acceleration, however, is opposed by the retarding forces of the asymmetry and electrophoretic effects as well as by the solvent viscosity, so that an ion ultimately moves with a uniform velocity determined by a balance of these opposing forceg. For a concentration c of a 1 1 strong electrolyte the concentration of cations, c+, is equal to that of anions, c. If the speeds of cations and anions are, respectively, u+ and u, the amount of charge crossing unit area of solution in unit time is... 

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