A Miniaturized GC with MEMS-Enabled Selective Preconcentration for Monitoring Exposure to Transportation-Related Air Pollutants

Details

• Personal Author:
  Agah M ; Marr L ; Nazhandali L
• Description:
  The NIOSH-supported project was aimed at the development of a miniaturized gas chromatography system to identify air hazardous pollutants (HAPs) found in transportation-related and other workplaces. Exposure to HAPs has been linked to a variety of health effects, such as cancer, asthma, autism, reduced fertility, and lower intelligence. Development of effective strategies for reducing occupational exposure to HAPs requires accurate, time-resolved measurement of exposure, but doing so is restricted by the unavailability of compact, lightweight, inexpensive portable analytical instruments. The research took important steps to address the need for lower cost, compact exposure monitors by merging microelectromechanical systems (MEMS) technology, microelectronics, and analytical chemistry to develop a portable GC system. The research resulted into the development of a Zebra GC, a ready-to-deploy microfabricated gas chromatography (uGC) system. The Zebra GC was characterized for detecting HAPs at parts-per-billion (ppb) concentrations in complex mixtures. Microfabricated preconcentrator (uPC), a MEMS separation column with on-chip thermal conductivity detector (uSC-TCD), the flow controller unit, and all the necessary flow and thermal management as well as user interface circuitry were integrated to realize a fully functional uGC system. The research team performed extensive characterization of uPC and uSC-TCD for target analytes: benzene, toluene, tetrachloroethylene, chlorobenzene, ethylbenzene, and p-xylene. Limit of Detection (LOD) of approximately 1 ng was achieved, which corresponds to 10 min sampling time at a sampling flow rate of 1 mL/min for analyte present at 25 ppbv. The uGC system was compared against conventional Automated Thermal Desorption-Gas Chromatograph-Flame Ionization Detector (ATD GC-FID) system for real gasoline samples in simulated car refueling scenario. The uGC system detected five peaks-three of those were identified, and required approximately 3 orders of magnitude lower sample volume as compared to the conventional system. The other major contribution of the research has been the development of a new GC detector and its integration with a MEMS separation column. The detector is a plasma-based photo ionization detector and has been able to yield 10pg detection limit, comparable with that of FID, while consuming a few milliwatts of power. The stand-alone detector has been integrated with a separation columns on a single chip improving the overall separation efficiency of uGC. The new detector has a detection limit 2 orders of magnitude better than TCD and its output has insignificant fluctuation in the presence of temperature or pressure programming. The detector is more suitable than TCD for integration into Zebra GC and provides a better solution for near real-time detection of HAPs. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Air Pollution, Indoor Asthma Asthma, Occupational Benzene Chemistry Hazardous Substances Mental Health Neoplasms Occupational Health Risk Assessment Risk Factors Safety Toluene Transportation Workplace

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• Keywords:
  Air-contamination Analytical-instruments Benzenes Bronchial-asthma Cancer Chemical-composition Chemical-properties Exposure-levels Gas-chromatography Hazards Health-hazards Mental-health Monitoring-systems Monitors Pollutants Psychological-factors Risk-factors Sampling Toluenes Transportation-industry Work-environment Workers

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• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-12
• NIOSHTIC Number:
  nn:20047185
• NTIS Accession Number:
  PB2016-101848
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-010330, 2015 Sep; :1-12
• Contact Point Address:
  Masoud Agah, PHD, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
• Email:
  agah@vt.edu
• CAS Registry Number:
  Benzene (CAS RN 71-43-2) ; Chlorobenzene (CAS RN 108-90-7) ; Ethylbenzene (CAS RN 100-41-4) ; Tetrachloroethylene (CAS RN 127-18-4) ; Toluene (CAS RN 108-88-3)
• Federal Fiscal Year:
  2015
• Performing Organization:
  Virginia Polytechnic Institute and State University
• Peer Reviewed:
  False
• Start Date:
  20120701
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20150630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9ec82e5d0f880e04e9c7f17a184aea6c025bf7be75012d5dd77c49e4704ba8ddd942a3293377036f8b1617b963c63287842bd0c7c3894d571438938a9bcdb87a
• Download URL:
  https://stacks.cdc.gov/view/cdc/218612/cdc_218612_DS1.pdf
• File Type:
  [PDF - 553.69 KB ]