DETERMINATION OF THE ISOELECTRIC POINT OF THE CAPILLARY WALL IN CAPILLARY ELECTROPHORESIS - APPLICATION TO PLASTIC CAPILLARIES

A refined method for measuring endoosmotic flow in capillaries based o n weighing the amount of liquid transferred is described. The method h as been applied to the estimation of isoelectric points of two types o f plastic capillaries (polytetrafluoroethylene and polytetrafluoroethy lene-polyhexafluoropropylene copolymer). Contrary to expectation both plastic capillaries exhibited considerable electroosmotic flow and cha nges in hydrodynamic flow resistance without applied voltage. The natu re of these phenomena is discussed.