High-Speed, Comprehensive, Two Dimensional Separations of Peptides and Small Molecule Biological Amines Using Capillary Electrophoresis Coupled with Micro Free Flow Electrophoresis

Two-dimensional (2D) separations are able to generate significantly higher peak capacities than their one-dimensional counterparts. Unfortunately, current hyphenated 2D separations are limited by the speed of the second dimension separation and the consequent loss of peak capacity due to under sampling of peaks as they elute from the first dimension separation. Continuous micro free flow electrophoresis (μFFE) separations eliminate under sampling as a limitation when incorporated as the second dimension of a 2D separation. In the current manuscript we describe the first coupling of capillary electrophoresis (CE) with μFFE to perform 2D CE × μFFE separations. The CE separation capillary was directly inserted into the μFFE separation channel using an edge on interface. Analyte peaks streamed directly into the μFFE separation channel as they migrated off the CE capillary. No complicated injection, valving, or voltage changes were necessary to couple the two separation modes. 2D CE × μFFE generated an ideal p...