« Previous AbstractSPME sampling of BTEX before GC/MS analysis: examples of outdoor and indoor air quality measurements in public and private sites    Next Abstract"Sex pheromones produced by male boll weevil: isolation, identification, and synthesis" »

Analyst

Title:		Thermogravimetric calibration of permeation tubes used for the preparation of gas standards for air pollution analysis
Author(s):		Tumbiolo S; Vincent L; Gal JF; Maria PC;
Address:		"Laboratoire de Radiochimie, Sciences Analytiques et Environnement, Faculte des Sciences, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France"
Journal Title:		Analyst
Year:		2005
Volume:		20050830
Issue:		10
Page Number:		1369 - 1374
DOI:		10.1039/b508536e
ISSN/ISBN:		0003-2654 (Print) 0003-2654 (Linking)
Abstract:		"Sources of VOC (Volatile Organic Compounds) reference-materials at ppm and ppb levels are needed for calibration of air monitoring instruments. The permeation-tube technique is considered effective for the preparation of low concentration standards of high accuracy and stability. In this work, purpose-built PTFE permeation tubes, containing benzene, toluene, ethylbenzene, o-xylene or m-xylene (BTEX) were accurately and rapidly calibrated. Using the sensitive thermo-balance of a thermogravimetric apparatus, very low permeation rates were determined by the continuous monitoring of the tube weight loss as a function of time. Permeation rates in the range from 25 to 350 ng min(-1) were determined with precision. Thermogravimetry appears to be a rapid method for the measurement of weight loss at constant temperature, allowing rapid characterization and recalibration of permeation tubes. A detailed study on toluene, chosen as a typical case, showed that there are variations of the permeation rate in the long term. The temperature dependence of the permeation coefficient was also explored and permeation rates were shown to display an Arrhenius behavior in the temperature range 304-324 K. Thermodynamic parameters influencing the permeation were discussed"
Keywords:		Air Pollutants/*analysis Calibration Environmental Monitoring/*instrumentation/methods Gravitation Temperature;
Notes:		"MedlineTumbiolo, Simonetta Vincent, Luc Gal, Jean-Francois Maria, Pierre-Charles eng Research Support, Non-U.S. Gov't England 2005/09/21 Analyst. 2005 Oct; 130(10):1369-74. doi: 10.1039/b508536e. Epub 2005 Aug 30"