Gibbs-Donnan equilibrium osmotic pressure

Be able to compute the equilibrium state, osmotic pressure, and membrane potentials of proteins and other charged species (Gibbs-Donnan equilibrium) (Sec. 

Note that the sodium ion concentrations in the two compartments are quite different in this last case, as are the hydroxyl ion concentrations. This is the Gibbs-Donnan equilibrium effect. The fact that each ion partitions unevenly between the two compartments results in a contribution to the osmotic pressure from the ions in addition to that which results... 

The encapsulation of the impermeable solute and its counterions creates an ion gradient across the membrane, causing ions to flow out of the hypertonic volume if both cations and anions are permeable. This effect reduces the osmotic pressure exerted by the impermeable solute. The result is a transmembrane potential and an altered distribution of ions, known as the Gibbs-Donnan equilibrium [116,117]. For a permeable cation, the ratio of its interior to exterior concentration (r) is equal to... 

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