Abstract
Performance of a diffusion sampler was evaluated for determination of volatile organic compounds (VOCs) such as toluene, ethylbenzene, xylene and styrene in a small chamber with a gas generation system. The diffusion sampler consists of porous polyolefin tube uniformly packed with carbon molecular sieves as a collection media. Collected VOCs were then extracted with carbon disulfide by mild shaking and determined by a capillary gaschromatography using flame ionization detector (GC-FID) . Recovery from spiked samplers was 94 %-104 % for 10 μg of VOCs except styrene (66 %) which polymerized in the solvent. The coefficient of variation for triplicate analysis of the amount of VOCs collected by this sampler was under 9 % for each component. Freundlich's adsorption isotherms were applied to the relationship between amounts of VOCs collected on the sampler and air concentrations measured by active samplings covering wide range of concentrations of VOCs. However, uptake rates derived from slopes of linear regressions can be conveniently used for conversion of the VOCs amount on the diffusion sampler to the air concentration in the case of measuring Japanese Indoor Air Guideline levels. While the uptake rate showed slight temperature dependence, humidity had no influence on the collection efficiency of the diffusion sampler.
