Teorell-Meyer-Sievers theory

In ion-selective electrode potentiometry, the cell potential reflects the dependence of the membrane potential on the primary ion activity (concentration). According to the Teorell-Meyer-Sievers (TMS) theory, the sum of... 

In ISE potentiometry, the cell potential reflects the dependence of the membrane potential on the primary ion activity (concentration). According to the Teorell-Meyer-Sievers (TMS) theory, the membrane potential is the sum of three potential contributions namely the phase boundary potentials generated by ion-exchange processes at both interfaces, ((()i - c )n, i) and (([)n, 2 4>2). and the inter membrane diffusion potential, (c )ni i - <[)ni,2). If the membrane composition is constant and there are no concentration gradients within the membrane, then the membrane diffusion potential is zero and the membrane potential can be described by phase boundary potentials (see Figure 10.3b). This approach is also used to treat the response of ISE made with a range of membranes. 

Fixed Charge Theory. As a result of combining the above two theories, a fixed charge membrane theory was developed by Teorell and Meyer and Sievers. The theory includes the equilibrium of the electrochemical potentials of ions at the membrane boundaries and the diffusion of ions in the membrane. Therefore, the total membrane potential E is composed of three separate potential differences Eo corresponds to the first transition region between the solution (o) and membrane phases, difl corresponds to the ion diffusion potential in the membrane, and corresponds to the other transition region between membrane and the solution (i) phases (see Figure 26B). Thus, the transmembrane potential is... 

The electrical potential difference at both sides of a membrane separating two solutions of the same electrolyte but different concentrations (Ci, C2) is called membrane potential (AOm). The Teorell-Meyer-Sievers (or TMS) theory [37, 38] assumes the membrane potential can be considered as the sum of three terms associated with two different contributions ... 

The search for models of biological membranes among porous membranes continued in the twenties and thirties. Here, Michaelis [67] and Sollner (for a summary of his work, see [90] for development in the field, [89]) should be mentioned. The existence and characteristics of Donnan membrane equilibria could be confirmed using this type of membrane [20]. The theory of porous membranes with fixed charges of a certain sign was developed by Teorell [93], and Meyer and Sievers [65]. 

T. Teorell, An attempt to formulate a quantitative theory of membrane permeability, Proc. Soc. Exptl. Biol. Med., 1935, 33, 282 K.H. Meyer and J.-F. Sievers, La permeabilite des membranes I. Theorie de la permeabilite ionique, Helv. Chim. Acta, 1936,19, 649, 665. 

Earlier studies on theoretical thin membranes were continued by Teorell [S] and Meyer and Sievers [6], who in their theory attempted to interpret the behavior of practical, thick membranes, in contact on both sides with solutions containing the sort of ion which can produce a membrane potential. This initiated further research and many workers studied the perm-selective properties of ion-selective electrode membranes. As a result, ion transport across thick ion-selective membranes was considered as the basic concept of the theory of ion-selective electrodes. This theory was further elaborated by Eisenmann, Simon, and Buck. 

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