Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 259

BTEX is an acronym that stands for benzene, toluene, ethylbenzene, and xylenes that occur in the lower-boiling liquid fuels (Figure B-3). These compounds are some of the volatile organic compounds (VOCs) found in crude oil derivatives such as gasoline.

Figure B-3 Constituents of the BTEX Mixture.

Toluene, ethylbenzene, and xylenes have harmful effects on the central nervous system. BTEX compounds are notorious due to the contamination of soil and groundwater, which typically occurs near crude oil and natural gas production sites, and petrol stations and other areas with underground storage tanks (USTs) or above-ground storage tanks (ASTs) containing gasoline or other crude oil-related products.

The analysis for the BTEX group is performed using a purge and trap device which, owing to differences in volatility and water insolubility, easily separates the BTEX group from the complex sample matrix. In addition, the analytes are identified with a photo-ionization detector (PID) which responds selectively to aromatic hydrocarbon derivatives while showing only a small or negative response to paraffin derivatives, oxygenated hydrocarbon derivatives, and other components of the gas stream. Hence, the BTEX analysis is not only one of the most commonly requested, but also a fairly simple, straightforward method.

See also: BTX.