Correspondence between membrane potential and conductivity

Geophysics ◽  
1991 ◽  
Vol 56 (4) ◽  
pp. 461-471 ◽  
Author(s):  
P. N. Sen
Keyword(s):  
Membrane Potential ◽  
Transport Number ◽  
Activity Ratio ◽  
Ionic Concentration ◽  
Salinity Range ◽  
Liquid Junction Potential ◽  
Formation Factor ◽  
Liquid Junction ◽  
Water Conductivity ◽  
Junction Potential

Combining the membrane potential [Formula: see text] with the corresponding ideal membrane potential [Formula: see text] and the liquid junction potential [Formula: see text], for the same activity ratio, gives [Formula: see text]. [Formula: see text] and [Formula: see text] are the reciprocal of the average of the reciprocal water conductivity and reciprocal of cation and anion conductivities, and [Formula: see text]; and [Formula: see text] is the average of the ratio of the water to the rock conductivity [Formula: see text] with respect to [Formula: see text], where t is the transport number for the Na ion, [Formula: see text] is the ionic concentration, and [Formula: see text] is the activity coefficient. This relationship is independent of any model and does not even refer to the value of clay counterion concentration. Combining σ with [Formula: see text] gives the saturation dependent formation factor F, and thus the interpretation of shaly sands becomes no more difficult than for clean sands. Experimental data on 27 rocks for which both membrane potential and conductivity were measured by Smits (1968) and Waxman and Smits (1968) over a large salinity range are used to verify this relationship.

scholarly journals Electrodiffusion Phenomena in Neuroscience and the Nernst–Planck–Poisson Equations

Electrochem ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 197-215
Author(s):  
Jerzy J. Jasielec
Keyword(s):  
Electrical Potential ◽  
Signal Propagation ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Patch Clamp Technique ◽  
Poisson Equations ◽  
Cellular Environment ◽  
Electrochemical Transport ◽  
Insight Into ◽  
Junction Potential

This work is aimed to give an electrochemical insight into the ionic transport phenomena in the cellular environment of organized brain tissue. The Nernst–Planck–Poisson (NPP) model is presented, and its applications in the description of electrodiffusion phenomena relevant in nanoscale neurophysiology are reviewed. These phenomena include: the signal propagation in neurons, the liquid junction potential in extracellular space, electrochemical transport in ion channels, the electrical potential distortions invisible to patch-clamp technique, and calcium transport through mitochondrial membrane. The limitations, as well as the extensions of the NPP model that allow us to overcome these limitations, are also discussed.

An Improved Equation for the Liquid Junction Potential at the Interface of Different Solvents

1992 ◽  
Vol 45 (10) ◽  
pp. 1633 ◽  
Author(s):  
A Berne ◽  
C Kahanda ◽  
O Popovych
Keyword(s):  
Mixed Solvent ◽  
Electrolyte Solutions ◽  
Transport Numbers ◽  
Liquid Junction Potential ◽  
Aqueous Methanol ◽  
Liquid Junction ◽  
Chemical Potentials ◽  
Solvent Dependence ◽  
New Equation ◽  
Junction Potential

The component of the liquid-junction potential due to the diffusion of ions across an interface of electrolyte solutions in different solvents was formulated by taking into account the solvent dependence of the transport numbers, t, and of the chemical potentials of ions in the interphase region as determined from experimental data on their variation in the mixed-solvent compositions. The new equation was applied to NaCl/NaCl and HCl/HCl junctions between water and methanol-water solvents over the entire solvent range. Significant differences between the results obtained with the new equation and the old formulation, which treated the transport numbers as solvent-independent, were observed only for the HCl junctions involving 90-100 wt % aqueous methanol, where tH exhibits a sharp minimum as a function of the solvent composition.

Ion-selective electrodes for sodium and potassium: a new problem of what is measured and what should be reported.

1985 ◽  
Vol 31 (3) ◽  
pp. 482-485 ◽  
Author(s):  
A H Maas ◽  
O Siggaard-Andersen ◽  
H F Weisberg ◽  
W G Zijlstra
Keyword(s):  
Activity Coefficient ◽  
Theoretical Calculations ◽  
Pair Formation ◽  
Ion Selective Electrodes ◽  
Residual Liquid ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Normal Plasma ◽  
Sodium And Potassium ◽  
Junction Potential

Abstract For clinical purposes the activities of Na+ and K+ obtained with ion-selective electrodes in undiluted whole blood or serum should be multiplied by an appropriate factor to obtain the same values as the substance concentrations obtained by flame photometry. The factor is primarily dependent on the mass concentration of water in normal plasma divided by the molal activity coefficient of Na+ (or K+) of normal plasma. We discuss the value of the molal activity coefficient of Na+ obtained by theoretical calculations and by direct measurement. The discrepancies between theory and measurement (gamma Na+ of 0.747 and 0.73, respectively) may be due to some binding of Na+ (protein binding or ion pair formation), a small and variable residual liquid-junction potential, or certainty about the appropriate value for the ionic strength of normal plasma (0.16 mol/kg or somewhat higher).

Liquid junction potential between different solvents

1990 ◽  
Vol 283 (1-2) ◽  
pp. 435-440 ◽  
Author(s):  
Kosuke Izutsu ◽  
Toshio Nakamura ◽  
Mitsuo Muramatsu
Keyword(s):  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Junction Potential
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