AN ONLINE ELECTROPHORETIC CONCENTRATION METHOD FOR CAPILLARY ELECTROPHORESIS OF PROTEINS

A simple on-line electrophoretic concentration method for capillary el ectrophoresis of proteins with a semipermeable hollow fiber is propose d. A short, semipermeable hollow fiber is connected to the inlet end o f a capillary. An injection electric held is applied across the hollow fiber. Protein samples are electromigrated into the hollow fiber from a sample vial. Since the protein ions cannot pass through wall of the hollow fiber, protein ions are concentrated in the hollow fiber. Afte r a certain period of injection (concentration) time, an electric fiel d is applied across the hollow fiber and the capillary, and a conventi onal CE is carried out. The concentration effect of the method has bee n demonstrated successfully with model protein samples, cytochrome c, lysozyme, ribonuclease A, and alpha-chymotrypsinogen A. Experimental r esults show that the concentration factor is increased with the inject ion (concentration) time and the electrophoretic mobility of the prote ins. When the injection (concentration) time is 60 s, CE detection lim its of the model proteins can be lowered by 1000-fold for the present method. Factors affecting the concentration factors and the further im provements of the method are discussed.