Capillary isoelectric focusing hydrodynamic mobilization

Capillary isoelectric focusing separates analytes based on differences in their isoelectric points (pi) using the same principles as in preparative solution IEF. After a focusing step, that builds up a linear pH gradient in the capillary (controlled with zwitterionic internal markers), the analytes move as a function of their respective charge until they reach a position of zero charge (isoelectric point). The solution is then mobilized in CIEF to the detector hydrodynamically. 

In the presence of electroendosmosis, the mobilization of the focused zones is achieved by the EOF. The so called single-step isoelectric focusing is performed, however, under conditions in which EOF is controlled by additives and the dynamic coating of the capillary surface provides reduced bulk flow. This mode of CIEF can also be combined with hydrodynamic elution. 

In the following sections, techniques for performing isoelectric focusing in coated or uncoated capillaries in the absence or presence of additives will be discussed. Different electrophoretic and/or hydrodynamic mobilization procedures will also be considered. 

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