A MEMS based liquid microchromatographic system based upon (110) silicon.

摘要

In this work a MEMS based device was designed and fabricated for chromatographic analysis of liquid samples. The dimensions of this device compared to conventional systems are significantly reduced (2 inch silicon wafer versus bench scale laboratory equipment), therefore the amount of solutions required for analysis and the analysis time are several orders of magnitude decreased. Micro separation channels were fabricated in a (110) silicon wafer to perform multiple simultaneous sample analysis. Miniature conductivity detectors were integrated onto the separation channels for good resolution and fast response. Commercially available mechanical valves were used for a sample injection at the time while a micro-reservoir was designed and fabricated as a separate component to be integrated as a part of a complete chromatographic system in the future. A design of a miniature fluidic system for genetic as well as other medical, bio-chemical and other types of analysis, utilizing the individual components developed in this work, is proposed.; Numerous difficulties related to a sample injection and ion detection were addressed in this work, most issues were solved and some suggestions in terms of future work guidelines are made. The final prototype device was successfully fabricated, connected to the external pumping system, chemically activated and tested. Numerous separations were performed and the obtained results compared to the theoretical predictions. The separation effectiveness was tested for different flow rates, buffer pH levels, different concentrations of ions in the solution, and different types of ions. The overall performance of this non-optimized prototype device was very satisfactory and in the next stage of this project an optimized, integrated version of an on-chip chromatographic system could be fully developed.