CONTINUOUS, FREE-FLOW ELECTROPHORESIS - A MODIFIED APPROACH

Electrophoresis is an exceptionally effective method for separating sm all particles or large molecules in the colloidal size range, and is w idely used in biological and clinical studies to separate cells, virus es, and large proteins. It has become the standard analytical tool for detecting the presence of these materials. Despite the success of ele ctrophoresis in analytical and research applications, there has been m uch less success in using electrophoresis in preparative-scale applica tions to separate large quantities of materials. A new or modified con cept is described that eliminates some of the most serious problems th at have arisen in adopting electrophoresis for preparative-scale separ ations. The new concept uses a narrow-gap flow system between the elec trodes and eliminates or greatly reduces problems with thermal convect ion. In addition, the narrow gap can be a convenient annular region be tween two cylindrical electrodes. The electric potential is applied ac ross the annulus (or across the narrow flow channel) and the potential applied to the electrodes is reversed periodically. Between the rever sals of the electric field, the inner electrode (or one side of the na rrow flow gap) is rotated periodically in different directions. This p eriodic motion and alternating of the applied field displaces charged particles in the angular direction. The rate of displacement depends o n the electrophoretic mobility of the particles.