Method for electrophoretic focusing

A method for separation and collection of at least one sample component from a mixture of sample components comprising the steps of:

• a. providing an apparatus comprising a separation chamber and a plurality of purge chambers, and establishing a first buffer flow in the separation chamber in the axial direction, said first buffer flow having a first flow rate;
• b. establishing a second buffer flow in each of at least two of said purge chambers in the axial direction, said second buffer flow having a second flow rate, said second buffer fluid flow having a second flow rate higher than that of the first flow rate;
• c. establishing a third buffer flow in a plurality of purge chambers axially adjacent to said separation chamber and separated from the separation chamber by precision-pore insulated screens;
• d. establishing a fourth buffer flow into one of the purge chambers laterally through the separation chamber, then into and out of a second purge chamber to provide a uniform focusing fluid velocity in the separation chamber;
• e. introducing the mixture of sample components directly into the separation chamber flow entrance or through at least one injection port located in the separation chamber interior;
• f. applying an electrical potential transversely across the separation chamber in the form of a constant voltage gradient or a linearly varying voltage gradient to impart electrophoretic velocity to the fractional components in the separation chamber in the transverse direction perpendicular to the first buffer flow direction and parallel to the third buffer flow direction;
• and
• g. withdrawing at least one separated sample component.