The estimation of several  characteristic  numbers for definition of electrokinetic processes related with the working medium flow is carried out. A microhydrodynamic  model of electroconductive liquid is constructed to  accommodate  important parameters of real electrokinetic processes. In particular this model accounts for the non- one dimensionality  of the flow in the devices of capillary zone electrophoresis electroinjection analysis (ETA), and electrophoretically mediated microanalysis (EMMA) (for modification of the mixing mode).