Design, modeling and fabrication of mems-based multicapillary gas chromatography columns

Abstract

This paper describes different approaches to achieve high-performance microfabricated silicon-glass separation columns for micro gas chromatographic (µGC) systems. The capillary width effect on the separation performance has been studied by characterization of 250 µm-, 125 µm-, and 50 µm-wide single-capillary columns (SCCs) fabricated on a 10 × 8 mm2 die. To address the low sample capacity of these narrow columns, the paper presents the first generation of MEMS-based “multicapillary” columns (MCCs) consisting of a bundle of narrow-width rectangular capillaries working in parallel. The theoretical model for the high-equivalent-to-a-theoretical-plate (HETP) of rectangular MCCs has been developed, which relates the HETP to the discrepancies of the widths and depths of the capillaries in the bundle. Two-, four-, and eight-capillary MCCs have been designed and fabricated to justify the separation ability of these columns. These MCCs capable of multi-component gas separation provide a sample capacity as large as 200 ng compared to 10 ng for 50 µm-wide single capillary columns.