TRANSVERSE FLOW GATING INTERFACE FOR THE COUPLING OF MICROCOLUMN-LC WITH CZE IN A COMPREHENSIVE 2-DIMENSIONAL SYSTEM

A comprehensive two-dimensional (2D) separation system for the study of proteins based on size exclusion chromatography (SEC) and capillary zone electrophoresis (CZE) is presented. A new interface design is used to couple SEC, carried out in packed capillary columns of 250- and 100-mum inner diameters, together with CZE. This interface design uses a transverse flow of CZE buffer to prevent SEC column effluent from being electroinjected onto the CZE capillary until an injection is desired. This interface provides reproducible CZE injections while introducing minimal extracolumn band broadening into the system. The 2D system is completely automated under computer control. The relative merits of this interface design are presented through a comparison between the separations of protein standards using this interface and separations using a valve/loop approach.