VOC samples

Compounds which have been analysed by Purge and Trap/Headspace/GC-MS 

2- dichloropropane 1.3- dichloropropane 2.2- dichloropropane 1,1 -dichloropropene ethyl benzene hexachlorobutadiene isopropyl benzene /9-isopropyl benzene methylene chloride naphthalene n-propyl benzene styrene 1.1.1.2- tetrachloroethane tetrachloroethene toluene 1.2.3- trichlorobenzene 1.2.4- trichlorobenzene 1,1,1 -trichloroethane 1.1.2- trichloroethane trichloroethene trichlorofluoromethane 1.2.3- trichloropropane 1.2.4- trimethylbenzene 1.3.5- trimethylbenzene vinyl chloride o-xylene /-xylcne /9-xylene 

Internal standards and surrogates 4-bromofluorobenzene dibromofluoromethane toluene-d4 pentafluorobenzene 1.4- difluorobenzene chlorohcnzcnc-r/s 1.4- dichlorobenzene-d4 

Volatile internal standards with corresponding analytes assigned for quantitation pentafluorobenzene trichlorofluoromethane 

2-dichloropropane iodomethane methylene chloride 1,1,1 -trichloroethane 1,4-difluorobenzene benzene bromodichloromethane bromofluorobenzene (surrogate) 

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Klemp, M., A. Peters, and R. Sacks, High-Speed GC Analysis of VOCs Sample Collection and Inlet Systems, Environ. Sci. Technol., 28, 369A-376A (1994). 

Several existing protocols require a solvent (acetone, methanol, isopropanol) rinse as part of equipment decontamination for VOC sampling and 1 10 percent hydrochloric or nitric acid rinse for metal analysis sampling (DOE, 1996 USACE, 1994). These practices, successful as they may be in removing trace level contaminants, create more problems than they are worth. Organic solvents are absorbed by the polymer materials used in sampling equipment construction and appear as interferences in the VOC analysis. Acid destroys the metal surfaces of soil sampling equipment and induces corrosion. The use of solvents and acids is a safety issue and it also creates additional waste streams for disposal. 

Despite its widespread use in indoor VOC sampling, sorbent trapping provides no information about (1) all of the VOCs present in the sampled air since some VOCs are either not trapped by the sorbent(s) or are too reactive to remain on the sorbent surface and (2) the temporal variations in the concentrations of the VOCs that are being monitored. 

This is a very popular method of transferring indoor VOC samples trapped by... 

Table 1. Characteristics of the adsorption materials used for VOC sampling (Woolfenden andMcClenny, 1999).

This book reviews methods for measuring airborne compounds and includes recent developments from experts in the field. Topics range from optical remote sensing to VOC sampling and analysis to visibility research in national parks. 

Fig. 8.13 The ratio of ion intensities obtained by a Syft Voice200 SIFT-MS and a standard PTR-MS measuring VOC samples from the same sample stream with the HjO reagent ion in both instruments. (Courtesy Syft Technologies Ltd)...

The limit of detection for the direct aqueous injection method is comparable to that of the membrane inlet-PTR-MS but, unlike the latter, the former is not restricted to those compounds that show good permeability through the membrane. Furthermore the response time is as short as 20 s, making it possible to monitor relatively rapid changes in VOC sample concentration. An excellent illustration of the potential for direct aqueous injection is the detection of a variety of polychlorinated biphenyls and organic isocyanates in water using PTR-MS [11],... 

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