| Title: | Toward a microfabricated preconcentrator-focuser for a wearable micro-scale gas chromatograph |
| Author(s): | Bryant-Genevier J; Zellers ET; |
| Address: | "Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2029, United States; Center for Wireless Integrated MicroSensing & Systems, University of Michigan, Ann Arbor, MI, United States. Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2029, United States; Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-2029, United States; Center for Wireless Integrated MicroSensing & Systems, University of Michigan, Ann Arbor, MI, United States. Electronic address: ezellers@umich.edu" |
| DOI: | 10.1016/j.chroma.2015.10.045 |
| ISSN/ISBN: | 1873-3778 (Electronic) 0021-9673 (Linking) |
| Abstract: | "This article describes work leading to a microfabricated preconcentrator-focuser (muPCF) designed for integration into a wearable microfabricated gas chromatograph (muGC) for monitoring workplace exposures to volatile organic compounds (VOCs) ranging in vapor pressure from approximately 0.03 to 13kPa at concentrations near their respective Threshold Limit Values. Testing was performed on both single- and dual-cavity, etched-Si muPCF devices with Pyrex caps and integrated resistive heaters, packed with the graphitized carbons Carbopack X (C-X) and/or Carbopack B (C-B). Performance was assessed by measuring the 10% breakthrough volumes and injection bandwidths of a series of VOCs, individually and in mixtures, as a function of the VOC air concentrations, mixture complexity, sampling and desorption flow rates, adsorbent masses, temperature, and the injection split ratio. A dual-cavity device containing 1.4mg of C-X and 2.0mg of C-B was capable of selectively and quantitatively capturing a mixture of 14 VOCs at low-ppm concentrations in a few minutes from sample volumes sufficiently large to permit detection at relevant concentrations for workplace applications with the muGC detector that we ultimately plan to use. Thermal desorption at 225 degrees C for 40s yielded >/=99% desorption of all analytes, and injected bandwidths as narrow as 0.6s facilitated efficient separation on a downstream 6-m GC column in <3min. A preconcentration factor of 620 was achieved for benzene from a sample of just 31mL. Increasing the mass of C-X to 2.3mg would be required for exhaustive capture of the more volatile target VOCs at high-ppm concentrations" |
| Keywords: | "Carbon/chemistry Chemistry Techniques, Analytical/*instrumentation/*methods Chromatography, Gas/*instrumentation *Microtechnology Occupational Exposure/*analysis Reproducibility of Results Volatile Organic Compounds/*analysis Benzene Micro gas chromatogra;" |
| Notes: | "MedlineBryant-Genevier, Jonathan Zellers, Edward T eng R01-OH010297/OH/NIOSH CDC HHS/ T42-OH008455/OH/NIOSH CDC HHS/ Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. Netherlands 2015/11/05 J Chromatogr A. 2015 Nov 27; 1422:299-309. doi: 10.1016/j.chroma.2015.10.045. Epub 2015 Oct 17" |
