Toward a microfabricated preconcentrator-focuser for a wearable micro-scale gas chromatograph

Details

• Personal Author:
  Bryant-Genevier J ; Zeller ET
• Description:
  This article describes work leading to a microfabricated preconcentrator-focuser (microPCF) designed for inte-gration into a wearable microfabricated gas chromatograph (microGC) for monitoring workplace exposures to volatile organic compounds (VOCs) ranging in vapor pressure from approximately 0.03 to 13 kPa at concentrations near their respective Threshold Limit Values. Testing was performed on both single- and dual-cavity, etched-Si microPCF 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 1.4 mg of C-X and 2.0 mg 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 microGC detector that we ultimately plan to use. Thermal desorption at 225 degreesC for 40 s yielded >/= 99% desorption of all analytes, and injected bandwidths as narrow as 0.6 s facilitated efficient separation on a downstream 6-m GC column in <3 min. A preconcentration factor of 620 was achieved for benzene from a sample of just 31 mL. Increasing the mass of C-X to 2.3 mg would be required for exhaustive capture of the more volatile target VOCs at high-ppm concentrations. [Description provided by NIOSH]
• Subjects:
  Benzene Chromatography Microbiology Occupational Health Particulate Matter Safety Volatile Organic Compounds
• Keywords:
  Adsorbents Analytical Instruments Author Keywords: Preconcentrator Chromatographic Analysis Desorption Detectors Equipment Design Equipment Reliability Equipment Testing Gas Chromatography Gas Detectors Measurement Equipment Microfabricated Micro Gas Chromatography Microscopic Analysis Mobile Equipment Monitors Organic Compounds Particle Size Performance Capability Sampling Equipment Threshold Limit Values TLV VOC Mixture VOCs Volatile Organic Compounds Volatiles Wearable Technologies

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• ISSN:
  0021-9673
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  299-309
• Volume:
  1422
• NIOSHTIC Number:
  nn:20048071
• Citation:
  J Chromatogr A 2015 Nov; 1422:299-309
• Contact Point Address:
  Edward T. Zellers, Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2029, United States
• Email:
  ezellers@umich.edu
• CAS Registry Number:
  Benzene (CAS RN 71-43-2)
• Federal Fiscal Year:
  2016
• Performing Organization:
  University of Michigan, Ann Arbor
• Peer Reviewed:
  True
• Start Date:
  20130901
• Source Full Name:
  Journal of Chromatography A
• End Date:
  20170831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f8fa68f86632158c862479fcbcbb40be3b3dcedcdef4148c2c215e415dc541edf0fe07a651af3d70deb3a6dcd5022ad21241666b21fd59be6b433104927cd871
• Download URL:
  https://stacks.cdc.gov/view/cdc/202938/cdc_202938_DS1.pdf
• File Type:
  [PDF - 1.36 MB ]