A VERSATILE MEMS GAS CHROMATOGRAPH FOR DETERMINATIONS OF ENVIRONMENTAL VAPOR MIXTURES

Abstract

A microfabricated gas chromatograph ( GC) with several innovative and enabling design features is described. The microsystem incorporates capabilities for particulate exclusion, on-board calibration, sample preconcentration and thermal desorption, pressure-and temperature-modulated separations, and "spectral" detection with array of microsensors. It is intended to permit rapid determinations of complex mixtures of environmental contaminants at trace concentrations. The ultimate goal is to embed microcontroller and rf communications modules for deployment in high-performance distributed environmental monitoring networks, among other possible applications. Ultralow power dissipation is therefore a priority. This presentation reports on progress, to date, with an emphasis on the MEMS sensors and actuators employed. Device design, processing, and integration issues are reviewed. Pressure-tuned separations with a dual micro-column ensemble are demonstrated for the first time to effect the resolution of 13-vapor mixture at room temperature in under 4 minutes. A first-generation hybrid prototype GC capable of performing mixture separations in as little as 30 seconds with detection limits in the low part-per-billion concentration range is also presented.