Methods and apparatus for separating and mobilizing solutes in a solute

Abstract

The present invention provides processes for isoelectric focusing ('IEF') and associated detection, which incorporates a dynamic means of electroosmotic flow ('EOF') control during IEF and/or after IEF to effect solute mobilization. In accordance with the present invention, the EOF control during IEF and/or solute mobilization after IEF are accomplished by applying an external electric field, relative to an internal electric field, to modify the electroosmotic flow in the capillary. This can be done by disposing a conductive member at one or more locations outside and along the buffer column in the capillary. The conductive member may be statically charged or caused to conduct a current to create the external required electric field. The applied external electric field may be adjusted, relative to the internal electric field, during IEF as necessary to reduce or completely suppress EOF to prevent flow of the buffer. Upon the completion of IEF (irrespective of the method of reducing or removing EOF during IEF), the external electric field is adjusted, relative to the internal electric field, such that the buffer carrying the focused solutes is moved electroosmotically through the capillary past a detection point. The present invention is applicable to internally coated capillary which suppresses EOF even in the absence of the external electric field.