Improving micro free flow device performance

University of Minnesota Ph.D. dissertation. May 2014. Major: Chemistry. Advisor: Michael Bowser. 1 computer file (PDF); xiii, 109 pages.Micro free flow electrophoresis is a separation technique that continuously separates analyte streams as they travel through an electric field applied perpendicularly to the flow in a microfluidic device. The continuous nature of this separation technique makes it an ideal choice for a number of applications including long term continuous monitoring and as a second dimension separation technique in a two dimensional separation scheme. In order for micro free flow electrophoresis devices to reach their full potential in these applications, improvements to the stability of separated analyte streams and zero dead volume connections to these devices must be addressed. This work will detail a simple, yet effective, way for mitigating the effects of electrolysis bubbles on analyte stream stability in micro free flow electrophoresis devices by addition of surfactant or organic modifier to the electrolyte carrier buffer. The longest stable micro free flow electrophoresis separation performed on our devices is shown to support the effectiveness of this approach. An approach for making zero dead volume connections to micro free flow electrophoresis devices will also be detailed. The first two dimensional separation performed with a micro free flow electrophoresis device as the second separation dimension is shown to support the effectiveness of this interface. Finally, the fabrication and operation of a microchip electrophoresis-micro free flow electrophoresis device for seamless integration of two separation dimensions is shown