(212b) Radial Free Flow Electrophoresis for Preparative Separation of Proteins

Electrophoresis is established as a high resolution separation process for protein analysis, but its application for preparative separation in an industrial scale is nowadays restricted due to scale up problems. Different experimental and theoretical studies were devoted to develop alternative operating modes of electrophoresis in order to overcome such limitations. One promising method is free flow electrophoresis (FFE) where the separation is carried out in a flowing liquid film without a matrix medium - as the name ?free flow? implies.

This work deals with the development of FFE in a radial geometry with an accelerated inward flow. The electric field is applied perpendicular to the flow direction. A separation chamber is formed by two parallel ceramic membranes placed between the two electrodes. The distance between the two membranes and thus the separation distance is only a few millimetres. Generally, one major scale-up problem of FFE is the necessity to maintain the hydrodynamic stability of the flow. This requires that the temperature gradient caused by Joule heating must be kept sufficiently low so that the forced flow will remain predominant compared to the buoyancy-driven flow. For the radial FFE, due to the narrow separation chamber and due to intensive cooling at the outer wall of the membranes, the limitation according to Joule heating can be diminished.

Experimental approaches using a model mixture of proteins are carried out to define proper operating conditions according to electrokinetic effects. The performance of the radial FFE in terms of achievable resolution and production capacity are investigated.