Volatile organic compounds media

The El source has been the most widely used ion source over the past 60 years and continues to be the method of choice for the analysis (either qualitative or quantitative) of small- to medium-sized volatile organic compounds. The inherent reproducibility of the mass spectra has enabled the assembly of large spectral libraries. Computers associated with current generation instruments can efficiently (in a few seconds) search an unknown mass spectrum against tens of thousands of reference spectra in order to aid in the identification of an analyte. The general scheme of an El source includes the introduction of the vaporized analyte molecules into the ionization chamber, exposure of those molecules... 

The most variable aspect of carbon tetrachloride analysis is the procedure used to separate carbon tetrachloride from the medium and prepare a sample suitable for GC analysis. As a volatile organic compound of relatively low water solubility, carbon tetrachloride is easily lost from biological and environmental samples, so appropriate care must be exercised in handling and storing such samples for chemical analysis. Brief summaries of the methods available for extraction and detection of carbon tetrachloride in biological and environmental samples are provided below. 

Potential applications for this technology include the treatment of airstreams contaminated with volatile organic compounds (VOCs) from air stripping, soil vapor extraction, industrial air emissions, and for the cleaning of air in closed environments. PCO is best suited for waste streams with low concentrations of contaminants, and with low to medium flow rates. The AIR-11 process can operate consistently in conditions where flow rates and VOC concentrations are highly variable, even intermittent. 

The focus is on a small and medium enterprise (SME) for which the use of chemicals is a minor part of the entire production chain. The SME uses painting guns for painting and coating operations of metals. These guns are cleaned with chemical substances, i.e. low volatile organic compounds (VOCs). 

Tirkkonen, T., Mroueh, U.-M. and Orko, I. (1995) Tenax as a collection medium for volatile organic compounds. NKB Committee and Work Reports 1995 06 E. 

Koontz, M.D. and Hoag, M.L. (1995) Volatile organic compound emissions from particleboard and medium density fiberboard. Measuring and Controlling Volatile Organic Compounds and Particle Emissions from Wood-Processing Operations and Wood-Based Products, Proceedings No. 7301, Forest Products Society, WI, pp. 76-87. 

Volatile organic compounds (VOCs) were degraded in groundwater at the Naval Air Station, Pensacola, FL (NAS Pensacola) using Fenton-based in situ chemical oxidation [91]. Trichloroethene (TCE) at 2440 pg/L and its degradation products ds-1,2-dichloroethene (403 pg/L) and vinyl chloride (976 pg/L) were the major contaminants at this site. These contaminants were focused predominantly in a region from 35 to 45 ft below the surface. The soil at this site consisted of marine terrace sands of fine to medium quartz. An... 

Ionic liquids (room-temperature molten salts, ILs) are reviewed in Section 3.5.3 of this book. They have an essentially negligible vapor pressure and the ability to dissolve a wide range of organic and inorganic compounds, which makes them an attractive alternative reaction medium to volatile organic compounds. 

Tetrachloroethylene is a volatile organic compound that is widely distributed in the environment. It is released to the environment via industrial emissions, and it is released from building and consumer products. Releases are primarily to the atmosphere, but the compound is also released to surface water and land in sewage sludges and in other liquid and solid waste, where its high vapor pressure and Hemy s law constant usually result in its rapid volatilization to the atmosphere. Tetrachloroethylene has relatively low solubility in water and has medium-to-high mobility in soil, thus its residence time in surface environments is not expected to be more than a few days. However, it persists in the atmosphere for several months and may also persist in groundwater for several months or more. Because of its pervasiveness and ability to persist under eertain eonditions, the potential for human exposure may be substantial. It should be noted that the amount of tetrachloroethylene measured by chemical analysis is not necessarily the amount that is bioavailable. 

Waterborne dispersions containing poly(vinyl acetate) are widely used as adhesives for wood or wood-based materials. Their success can be attributed to several factors such as easy application, non-flammability, low toxicity and relatively low cost. In fact, high temperatures are generally not required to dry these adhesives, their shelf-life is long and water can be used to remove the residual product from tools. Furthermore, these adhesives show an extremely low toxicity profile due to the presence of water as dispersing medium and to the very low content of volatile organic compounds (VOCs). 

M.D. Koontz and M.L. Hoang, Volatile Organic Compound Emissions from Particleboard and Medium Density Fiberboard, Proceedings of Measuring and Controlling VOCs, No.7301, Forest Products Society, WI, USA, 1995, p.76-87. 

Composed-Based Medium Containing Naturally Occurring Microbes That Degrade Volatile Organic Compounds and Complex Odor Streams... 

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