MEMS-based microfluidic system for chromatographic analysis of liquid samples

A complete micro-chromatographic system has been designed on a (110) silicon chip and the column-detector sub-system has been demonstrated. This micro-configuration allows the active surface-to-cross sectional area to be maximized, consistent with fabrication and pressure drop issues. A separation column was designed as an array of parallel channels anisotropically etched in (110) silicon to reduce pressure drop and to provide a necessary large surface area at a short length. Sensing was done by use of integrated impedance electrodes, with the detector cell volume less than 1 nl, although integrated optical detection has also been initiated. The response time is improved by about two orders of magnitude (relative to traditional systems) and simultaneous multiple analysis capability is realized with this design. Fabrication of multiple impedance detectors at different locations along the length of a micro-channel will enable monitoring of the separation in progress. Although the present work supports only a linear column configuration, a serpentine version would consume only about one square millimeter of a chip area, thus further minimizing the device.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.