Progress toward a prototype MEMS gas chromatograph (μGC) designed for analyzing complex mixtures of volatile organic compounds (VOC) in breath is described. This µGC, named SPIRON, integrates a multistage preconcentrator/injector, a dual-microcolumn separation module, and a chemiresistor array detector with commercial minivalves and a minipump. Here, we describe results showing thermal control of all key system components and then present the rapid separation of two complex mixtures: one containing lung cancer biomarkers and the other containing tuberculosis biomarkers, both in backgrounds of 30 common breath VOCs. The fully assembled SPIRON µGC prototype is also presented.

Two fully integrated and automatically controlled MEMS gas chromatographs (µGC) were successfully deployed in the field to monitor trichloroethylene (TCE) at trace-level concentrations (0.6-80 ppb) in homes suffering from vapor intrusion (VI) from surrounding TCE-contaminated soil. Each instrument combines a high-volume sampling module (non-microfabricated) with a microanalytical module consisting of a microfocuser, dual microcolumns, and a chemiresistor array detector. A complete sampling and analytical cycle requires 15-30 min, depending on required sensitivity. Limits of detection as low as 0.02 ppb were achieved. TCE was separated from 45 co-contaminants. Use of the prototypes in fixed-site (temporal TCE fluctuations) and portable operating modes (spatial mapping of TCE) was successfully demonstrated. Good agreement with concentrations determined with standard reference methods was achieved.