  The mathematical model describing the non-stationary natural pH-gradient
arising under the action of an electric field in an aqueous solution of
ampholytes (amino acids) is constructed and investigated. The model is part of
a more general model of the isoelectrofocusing (IEF) process. To numerical
study of the model we use the finite elements method that allows to
significantly reduce the computation time. We also examine the influence of the
different effects (taking into account the water ions, the various forms of
Ohm's law, the difference between isoelectric and isoionic points of the
substances) on the process IEF.
