Microfabricated Gas Chromatograph for Trace Analysis

Microfabricated portable gas analyzers with high sensitivity and selectivity offer utility in a variety of critical applications including aviation security, food safety and toxic industrial waste monitoring. An integral component of such analyzers is the gas chromatographic (GC) column which is used for separations of an injected mixture based on the relative sorption of the various analytes in the carrier gas by the stationary phase. In this interim report, we describe our efforts in the design and development of a microfabricated GC column for the trace detection of hazardous chemicals. Specifically, in this work an optimized serpentine layout with a circular cross- sectional profile has been microfabricated. In this work, computational fluid dynamic (CFD) modeling has been employed as a method to aid in the GC column design optimization. Selectivity to hazardous hydrogen bond basic (HBB) analytes (e.g. TNT, GB, VX) was achieved by using an NRL developed hydrogen bond acid (HBA) sorbent polymer HCSFA2 as the stationary phase. HCSFA2 offers a higher partition coefficient than the more commonly used polysiloxanes.