Abstract: An electrophoresis apparatus comprising: a first electrode in a first electrode zone; a second electrode in a second electrode zone, the first electrode disposed relative to the second electrode so as to be adapted to generate an electric field in an electric field area therebetween upon application of an electric potential between the first and second electrodes; a first membrane disposed in the electric field area; a second membrane disposed between the first electrode zone and the first membrane so as to define a first interstitial volume therebetween; wherein at least one membrane being a barrier capable of controlling substantial bulk movement of liquid under the influence of an electric field; means adapted to provide fluids to the electrode zone and the interstitial volume, wherein one of the fluids contains a sample constituent, and wherein upon application of the electric potential, liquid is caused to move from the sample constituent through at least one membrane to an adjacent electrode zone and at