Design, Modeling and Fabrication of Mems-Based Multicapillary Gas Chromatography Columns

Abstract

This paper describes different approaches to achieve highperformance 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 singlecapillary columns (SCCs) fabricated on a 10 × 8 mm 2 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.

MEMS-based semi-packed gas chromatography columns

“…One alternative approach to open rectangular columns to address the deficiency in sample capacity is multicapillary columns that consist of several narrow channels that run in parallel and can provide higher sample capacities without a significant loss in the separation efficiency. However, as we have shown before, it can be very challenging to coat these columns using well-established conventional techniques due to the differential flow among the capillaries, thus reducing their separation efficiency [19][20][21].…”

Advancements in Microfabricated Gas Sensors and Microanalytical Tools for the Sensitive and Selective Detection of Odors

“…First of all, increasing channel depth contributes to greater volumes of the µ-column, which result in a higher sample capacity (i.e., maximum concentration of analytes that can be injected, without overloading the system) and flow-rates [ 237 ]. Second, reducing channel width fosters a better interaction between analytes and the stationary phase, which also contributes to their better segregation [ 238 ]. In addition, narrower channels enable to fabricate µ-columns with closer plates, which results in more compact devices or longer µ-columns within the same confined space.…”