Determination of volatile organic compounds in air using a dehumidified and ventilated diffusive sampler, thermal desorption and gas chromatography with flame ionization detection

Abstract

A portable dehumidified and ventilated diffusive sampler (DVDS) incorporating three diffusive tubes and a domestic battery-driven fan dryer was developed to solve the problems of high humidity and stagnant air for environmental monitoring of volatile organic compounds (VOCs). Using Tenax GR as adsorbent, thermal desorption and cryogenic on-column focusing prior to capillary GC analysis with flame ionization detection, the 10 most common aromatic and halogenated VOCs were determined with the DVDS, giving linear working ranges 3.2 pg m-3-770 mg m-3 for 1 h sampling, sampling rates of 0.64-0.98 ml h-1 and RSD of 4-6%. The good repeatability is due to the use of a small-diameter diffusive tube (0.32 mm id) and reproducible ventilation in the DVDS. The optimized analytical parameters are temperature 10-40 "C, relative humidity 0-100 %, sampling time 15-480 min and storage for up to 21 days. Quality assurance procedures were developed for the calibration and preparation of the DVDS. The reliability of the method was established by parallel determinations at a given field station using both the DVDS and the active sampling method.

Combination of Sorption Tube Sampling and Thermal Desorption with Hollow Waveguide FT-IR Spectroscopy for Atmospheric Trace Gas Analysis: Determination of Atmospheric Ethene at the Lower ppb Level

“…At present, the only method widely used for individual "nonmethane hydrocarbon" (C 2 -C 10 hydrocarbons) determination in urban, rural, and background air is a combined method based on sampling using chromatographic sorbent materials and determination with a gas chromatographic (GC) system combined with thermodesorption, cryofocusing, and capillary-GC with FID and MS detection. [16][17][18] The concept we pursue in the current study is a new generation of instruments based on a combination of sampling comprising an enrichment step utilizing chromatographic sorbents followed by thermodesorption, in combination with newly developed hollow waveguide (HWG) gas sensing modules 19 coupled to a FT-IR detection system. The analyzer we describe here is based on HWGs simultaneously serving as low-volume miniaturized gas cells and IR waveguide.…”

“…At present, the only method widely used for individual “non-methane hydrocarbon” (C 2 −C 10 hydrocarbons) determination in urban, rural, and background air is a combined method based on sampling using chromatographic sorbent materials and determination with a gas chromatographic (GC) system combined with thermodesorption, cryofocusing, and capillary-GC with FID and MS detection. − …”