Electroosmotic flow microchip capillary electrophoresis

Liu, Y., Fanguy, J.C., Bledsoe, J.M., Henry, C.S., Dynamic coating using polyelectrolyte multilayers for chemical control of electroosmotic flow in capillary electrophoresis microchips. Anal. Chem. 2000, 72(24), 5939-5944. 

Microchip capillary electrophoresis (MCE), like conventional capillary electrophoresis (CE) and most other chemical separation techniques, is heavily dependent on surface chemistry. This connection is obvious for techniques that use a stationary phase but is also apparent for separation modes like zone electrophoresis where the separation is based on the mobility of the ions. An important component of zone electrophoresis is the electroosmotic flow (EOF), which is a surface-derived phenomenon. Furthermore, the degree of surface hydrophobicity can cause adsorption resulting in band broadening. As a result of the significance of the surface chemistry, it is important to develop an understanding of methods that provide control of surface chemistry in MCE. This problem is more... 

Due to its simple optical devices, wide linear range of response and many well characterized CL systems, chemiluminescence (CL) is uniquely suited to on-line detection for /t-TAS. Some reports have shown that CL is an alternative promising detection method for capillary electrophoresis microchip. In the present work, some glass microchips were designed based on the flow injection and electroosmotic flow (EOF)-chemiluminescent devices and applied to determine transition metal ions and organic compounds. 

Another approach that has been used to introduce a sol-gel functionality into a microchip has been to either imbed the sol-gel into the microchip or to coat a microchip channel with a sol-gel. The method to imbed sol-gel functionality into a chip involved preparing a PDMS chip with silica nanoparticles homogeneously distributed throughout the PDMS [4]. This approach produced a chip that was more hydrophilic than normal PDMS. In addition, when these chips were used for capillary electrophoresis analysis, the electroosmotic flow was much higher than in other PDMS chips. 

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