Evaluating Porous-Layer Open-Tubular Capillaries as Vapor Preconcentrators in a Microanalytical System

Details

• Personal Author:
  Cai QY ; Morishita M ; Zellers ET ; Cai QY ; Morishita M ; Zellers ET
• Description:
  Measuring environmental concentrations of organic vapors with microfabricated chemical sensors or sensor arrays often requires a means to enrich collected samples prior to detection. With such an application in mind, a preliminary evaluation is described of two porous-layer open tubular (PLOT) capillary traps as vapor preconcentrators for a series of vapors. Short (1-cm) sections of commercial PLOT-Q and PLOT-S capillary having wall coatings of styrene-divinylbenzene copolymer and vinylpyridine-divinylbenzene copolymer, respectively, are fitted with a metal sleeve for rapid thermal desorption of preconcentrated vapor samples, and tested using a downstream 97-MHz polyisobutylene-coated surface acoustic wave (SAW) sensor. Calibrated responses to vapors of 2-butanone (MEK), trichloroethylene (TCE), toluene, and m-xylene are collected with and without preconcentration. Dimethylmethylphosphonate could not be efficiently desorbed from either PLOT trap. For the remaining vapors, increases in sensitivity of 3-9-fold are achieved by preconcentrating and analyzing just 1 ml of sample air. Calculated limits of detection (LOD) range from 1-8 ppm. Differences in sensitivities are observed between the PLOT-Q and PLOT-S sampling trains for MEK and TCE. A theoretical model of penetration yields limiting values of flow rate and trap dimensions. Measured 10%-breakthrough times at 1 ml/min ranged from 1 to 6 min and, for PLOT-Q, are = modeled values obtained using the modified Wheeler equation. The implications of the results for the design and operation of microanalytical systems for vapor analytes are discussed. [Description provided by NIOSH]
• Subjects:
  Occupational Health Safety Solvents Volatilization
• Keywords:
  Organic-solvents Sampling Sampling-methods Vapor-detectors Vapors
• ISSN:
  0925-4005
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article ; Journal Article
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH) ; National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health ; Workplace Safety & Health
• Location:
  North America ; North America
• Pages in Document:
  244-253
• Volume:
  67
• Issue:
  3
• NIOSHTIC Number:
  nn:20030921
• Citation:
  Sens Actuators B Chem 2000 Sep; 67(3):244-253
• Contact Point Address:
  Department of Environmental Health Sciences, University of Michigan, 109 S. Observatory St., Ann Arbor, MI 48109-2029, USA
• Email:
  ezellers@umich.edu
• Federal Fiscal Year:
  2000
• Performing Organization:
  University of Michigan, Ann Arbor
• Peer Reviewed:
  True
• Start Date:
  19980930
• Source Full Name:
  Sensors and Actuators B: Chemical
• End Date:
  20060531
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9e9cc7410044eed9099b497fe3936c87437fa4db475f7b4d7e1eec5ad242e0b8723e22ad0150c48647ece2d29eb14cec5dc462f63a0ee66d284f314ac06779e6
• Download URL:
  https://stacks.cdc.gov/view/cdc/191357/cdc_191357_DS1.pdf
• File Type:
  [PDF - 221.52 KB ]