(84b) Dispersion Effects of Microchannel Configurations and Turn Geometries

Microchannels are essential components of microreactor or microseparation devices. In the process of accomodating long microchannels on a small chip area, there exists a choice of channel configurations and a choice of turns. The objective of this paper is to understand how microchannel configurations and bend geometries affect the separation performance of a micro gas chromatographic column operating under laminar conditions.

Gas flows in macro-sized curving ducts have been characterized with Dean flow vortices. Related research has been done in the field of micro liquid chromatography (MicroLC) and microcapillary electrophoresis (MicroCE). Flow around turns in MicroCE are characterized with race-track effect due to the difference in inner and outer turn path length. MicroCE society has proposed a number turn geometries to correct the race-track effect. The microchannels are fabricated in silicon and connected to a conventional gas chromatograph operating in high speed mode. The paper will present RTD measurements to compare the gas chromtographic performance of different channel configurations and bend shapes.