Volatile organic compounds passive sampling

Begerow J, Jermann E, Keles T, et al. 1995. Passive sampling for volatile organic compounds VOCs in air at environmentally relevant concentration levels. Fresenius Journal of Analytical Chemistry 351(6) 549-554. 

Cao, X.-L., and C. N. Hewitt, Build-up of Artifacts on Adsorbents during Storage and Its Effect on Passive Sampling and Gas Chromatography-Flame Ionization Detection of Low Concentrations of Volatile Organic Compounds in Air, . /. Chromatogr. A, 688, 368-374 (1994). 

Vroblesky, D.A. 2007. Passive diffusion samplers to monitor volatile organic compounds in groundwater. In R. Greenwood, G.A. Mills, and B. Vrana (eds), Passive Sampling Techniques in Environmental Monitoring, pp. 295-309. Amsterdam Elsevier. 

Cao XL, Hewitt CN. 1991. Evaluation of Tenax-GR adsorbent for the passive sampling of volatile organic compounds at low concentrations. Atmos Environ Part A 27A 1865-1872. 

The EPA (US Environmental Protection Agency) describes a process for sampling and analysis of volatile organic compounds (VOCs) in the atmosphere. It is based on the collection of air samples in passivated stainless steel canisters (SUMMA canisters). The organic components are separated by GC and determined using conventional GC detectors or by mass spectrometry (Figure 4.1). The use of mass spectrometers allows the direct positive detection of individual components (Madden, 1994). 

Passive samplers are widely used in monitoring volatile organic chemicals (VOCs) in groundwater. Such samplers have the potential to reduce costs of monitoring from the high levels associated with the use of pumps to sample the test wells. Moreover, the risk of loss of volatile analytes during sample transport and storage is substantially reduced once the compounds are accumulated in the sampler sorption phase. 

Thermal desorption Volatile compounds in gases such as pollutants in air can be trapped in a small adsorption tube, either by pumping the gas through or by passive diffusion. The packing in the trap can be chosen from a wide variety of adsorbents (molecular sieves, graphitized carbon blacks, organic polymers). After sample collection the adsorption tube is rapidly heated in a stream of purge gas which transports the released analytes to the GC column where the separation runs. 

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