Electrophoresis fundamental experiments

A number of different approaches have been taken to describing transport in porous media. The objective here is not to review all approaches, but to present a framework for comparison of various approaches in order to highlight those of particular interest for analysis of diffusion and electrophoresis in gels and other nanoporous materials. General reviews on the fundamental aspects of experiments and theory of diffusion in porous media are given... 

By a suitable combination of some fundamental electrophoretic techniques their advantages can be exploited for better separations. For instance, in discontinuous electrophoresis (disc-electrophoresis), isotachophoretic arrangement is utilized in the first part of the experiment in order to concentrate the sample components, and to arrange them according to their effective mobilities. In the second part of the experiment individual zones are separated on the principles of zone electrophoresis. In other cases combinations of electromigration and other principles (for instance, immunoelectrophoresis) are exploited. 

Fundamental studies on such systems ate scarce, but some attention has been paid to dispersion in hydrocarbon solutions of surface-active agents for which the ionic concentrations are extremely small, e.g. 10 ° mol dm corresponding to I/k 10 psn. Since 1/k is large the capacity of the double layer is small and only a small surface charge density is necessary to obtain an appreciable surface potential Furthermore, the slow decay in potential from the surface means that the zeta potential, readily obtained from electrophoresis experiments, may be equated with considerable accuracy to the surface potential. 

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