A Wearable Mems Gas Chromatograph For Multi-Vapor Determinations

A wearable gas chromatographic microanalytical system (GC) for near-real-time recognition and quantification of volatile organic compounds (VOC) in complex mixtures encountered in working environments is described. The battery powered GC prototype measures 20x15x9 cm, weighs just 2.1 kg, has 3-D printed packaging, and can be worn on the belt to autonomously measure exposures to industrial VOC mixtures several times per hour. Novel features of the discrete DRIE-Si/Pyrex micro-component chips include a dual-adsorbent preconcentrator/focuser (PCF) with split-flow injections as narrow as 600 ms (benzene), a 6-m long segmented separation mu column with zone heating for power efficient separations; and a fluidically redesigned array of mu chemiresistors (mu CR) with thiolate-monolayer protected Au nanoparticle (MPN) interface films that provide sensitive detection and diverse response patterns for recognizing eluting VOCs. Embedded microcontrol allows for continuous unattended operation and storage of data for post-exposure downloading and analysis. In our first tests of the complete prototype, we have demonstrated reproducible analyses of mixtures of up to 9 VOCs in 2.5 min (sampling and analysis), linear calibration curves, unique response patterns for mixture components, sub-ppm LODs, and stable responses for 5 days. Initial mock field tests demonstrated successful monitoring of rapidly changing concentrations of three VOCs during a solvent handling task. (C) 2016 Published by Elsevier Ltd.