Separation of micromolecules

This invention is directed to an apparatus and method for the separation of molecules, particularly micromolecules having a molecular mass of less than 5000 Dalton. The present invention is directed to an apparatus for separating micromolecules by electrophoretic separation, the apparatus comprising: (a) an anode; (b) a cathode disposed relative to the anode so as to be adapted to generate an electric field in an electric field area therebetween upon application of a voltage potential between the anode and the cathode; (c) a separation membrane disposed in the electric field area; (d) a first restriction membrane disposed between the anode and the separation membrane so as to define a first interstitial volume therebetween; (e) a second restriction membrane disposed between the cathode and the separation membrane so as to define a second interstitial volume therebetween; and (f) means adapted to provide a sample constituent in a selected one of the first and second interstitial volumes; wherein upon application of the voltage potential, a selected separation product is removed from the sample constituent, thorough the separation membrane, and provided to the other of the first and second interstitial volumes, wherein a micromolecule is capable of being retained in at least one of the interstitial volumes, and wherein a micromolecule is capable of being retained in at least one of the interstitial volumes.