Reducing Electroosmotic Flow Enables DNA Separations in Ultrathin Channels

摘要

Research focused on the development of a procedure to reduce or eliminateelectroosmotic flow (EOF) in 25 microns i.d. fused silica capillaries. An emphasis has been made on devising a procedure to coat 25 microns i.d. fused silica capillaries with a polymer that will enable DNA to migrate through the capillary, against electroosmotic flow, and continuously separate in ultrathin channels. Chapter 2 focuses on solving the problem of analytes adsorbing on the surface of the capillaries and its effect on reproducibility and efficiency of separations. This problem is especially significant when large molecule (DNA) separations are being studied. To overcome the problem of solute-wall interaction, a procedure for modifying the surface of fused silica capillaries with acrylamide and for measuring the rate of electroosmotic flow (EOF) in capillary electrophoresis (CE) is reviewed. Chapter 3 combines CE with ultrathin channels enabling the ability to evaluate individual and multiple plugs of double stranded DNA (dsDNA) that are detected by laser induced fluorescence (LIF). This technique combines the parallel processing capabilities of channel electrophoresis with the advantages of sample introduction with a single capillary. Ultrathin channels using 25 microns spacers between quartz plates allow for the efficient dissipation of Joule heat and decreased separation time. This technique demonstrates that the coated 25 microns i.d. capillaries can be used as a transfer device to smaller ultrathin channels.