Z-SHAPED FLOW CELL FOR UV-DETECTION IN CAPILLARY ELECTROPHORESIS

A longitudinal (Z-shaped) flow cell for improved UV detection for capillary electrophoresis was examined and compared with perpendicular (on-column) detection. Bending of a small section of the capillary column into a Z-shaped flow cell has no adverse influence on the electrophoresis process. With enhancements in signal-to-noise ratio of up to 6-fold for 3-mm Z-shaped flow cells, a considerable improvement in detectability is possible. The increase in signal of up to 14-fold in comparison with on-column UV detection illustrates the potential of this new type of capillary flow cell. The loss in resolution caused by the extended path length is less pronounced than expected, and can be tolerated in many of the CE separation modes.