PURIFICATION OF BIOPRODUCTS BY FREE-FLOW ZONE ELECTROPHORESIS - CHOICE OF PROCESSING PARAMETERS

Free-flow zone electrophoresis may be used to purify biological sample s, due to differences in electrophoretic mobility, in absence of a mat rix - most frequently a gel - thus enabling the biological integrity o f even fragile molecules to be preserved. However, the process is more complicated than its principle suggests due to different transport ph enomena interfering with electrophoretic migration, with the resultant separation depending both on separation effects and dispersive phenom ena. The physical origin of the main effects involved was identified. Mathematical expressions were proposed to estimate the influence of th e crescent effect and electrohydrodynamics on the process. In this pap er, these equations are used to determine the minimum difference in el ectrophoretic mobility required for a separation to be achieved with r espect to the processing parameters. h methodology is proposed which d efines the conditions under which the difference in electrophoretic mo bilities equals that calculated when considering the influence of disp ersive phenomena. Optimized separations of the whey proteins lactoferr in and albumin, known to interact strongly, and the purification of a monoclonal antibody from a mouse ascitic fluid illustrate the approach .