2005 , Volume 10, № 4, p.99-106

Using symbolic calculations, stability of ion concentration gradients in electrolytes is investigated. The analogy between hydrodynamics described by Navier-Stokes equations, and the dynamics of ions, governed by the system of the Nernst-Plank equations is discussed. Within the framework of this analogy presence of discontinuing, automodelling and unstable solutions of the Nernst-Plank equations is anticipated. Unstable solutions may arise in a system with more than two sorts of ions. A criterion of stability of stationary distributions of ions in electrolytes in external electric fields is obtained. It is shown, that ionic distributions with more than one sort of anions and more than one sort of cations are essentially unstable. The obtained results have practical applications in electrofocussing of biological macromolecules in pH gradients.