Recycling isoelectric focusing and isotachophoresis

A new apparatus for large scale preparative isoelectric focusing in free solution is described. Its main characteristic is rapid fluid recirculation with but short residues times in the electric field. For the first time the recycling principle was also applied to preparative isotachophoresis, by incorporating into the system a computer controlled leader counterflow. The rapid recirculation permits application of unusually high electrical power for rapid resolution, as it suppresses fluid flow instabilities arising from electrohydrodynamic effects.