Overall Column Electroosmotic Pump - Capillary Ion Chromatography Hyphenated Techniques

Driving and control of microfluid is a key subject in the microfluidic devices. In the various kinds of micropumps, electroosmotic pump (EOP) is unique one which use electroosmotic flow (EOF) to drive the fluid, and has attracted more and more attention because of its distinguished features such as easy-fabrication, no moving parts, stable flow, high pressure output and so on. The purpose of this thesis is to develop the preparation technology of EOP circuit and the related interface applied to the chromatographic system.A convenient and rapid method for preparing silica xerogel column applied for EOP has been developed and evaluated. The whole preparation process is less than 4 h, and the achieved column has many advantages such as high pressure drop and high resistor, which is well suited for the requirements of EOP. The performance of the silica xerogel column-based EOP has been evaluated from the aspects including current, flow rate, pressure output. And the achieved data showed that the EOP had good performance.A novel cascade EOP has been presented, aiming to increase the pressure output of EOP. The fabrication procedure is as follows. Firstly, Cation exchange monolithic (CEM) column and anion exchange monolithic (AEM) column was prepared by optimizing the monomer and porous reagent recipe. The cascade EOP was fabricated by alternatively connecting CEM column and AEM column in serial, in which the CEM column produces forward electroosmotic flow (EOF) in a direction to cathode when applied for forward voltage, while the AEM column produces reversed EOF in a direction to anode when applied for reversed voltage. Thus the switch of electric polarity could be easily achieved by this strategy, eliminating the drawback associated with the previous designs. The performance of the cascade EOP was also evaluated.In combination with a microscale electrodialytic generator, the feasibility of coupling the silica monolithic column-based EOP and capillary ion chromatography has been demonstrated and also successfully applied for the effective analysis of common anions. This strategy solves the application of pure water as a sole solvent for chromatographic system, and at the same time provides a new micropump option for the capillary ion chromatography.