Isoelectric Separation

Model ID: 10626


This modeling example applies the Transport of Diluted Species interface to model a separation process. A stream containing six different ionic species is divided into pure component streams by means of migrative transport in an electric field. Free flow electrophoresis can be used to separate macromolecules such as proteins, based on their mobility perpendicular to the flow of the carrier fluid. If, in addition, a pH gradient is applied across the carrier flow, then molecules can be focussed along their isoelectric points. The isoelectric point is the pH at which a the molecule has zero net charge. Molecules with a positive net charge will travel in the direction of the electric field, along the pH gradient, until they reach the isoelectric point. At this instance the migrative transport is switched off as the molecules net charge is zero. Similarly, anionic species travel in the direction opposite of the electric field.