Desorption of BTEX from activated charcoal using accelerated solvent extraction: evaluation of occupational exposures

Abstract

A procedure for the determination of benzene, toluene, ethylbenzene and o-xylene, m-xylene and p-xylene (BTEX) in occupational environments is proposed. These compounds are extracted from activated charcoal using accelerated solvent extraction. Operational parameters are optimized and quantitative recovery is obtained using acetonitrile as the extraction solvent and 1-mL extraction cells, a preheat time of 2 min, a temperature of 160 degrees C, a pressure of 1,500 psi, a static period of 5 min, a flush volume of 110%, two cycles and a purge time of 90 s. Determination of BTEX compounds is carried out by gas chromatography using a flame ionization detector. The recoveries, obtained for a confidence level of 95%, are 91 +/- 4, 100 +/- 3, 104 +/- 2, 93 +/- 4, 99 +/- 2 and 99 +/- 2% for benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, respectively. The detection limits are 0.5 microg for benzene, 0.7 microg for toluene and 1.0 microg for the other compounds. The proposed procedure has been applied to real samples collected in several workplaces, like a microbiology laboratory, an analytical chemistry laboratory, a printer's, a car repair shop and a petrol station. From the results obtained, it can be concluded that the occupational exposures determined are always acceptable because they are lower than the tenth part of the recommended exposure limits (VLA-ED and VLA-EC).

Occupational Exposure of Diesel Station Workers to BTEX Compounds at a Bus Depot

“…Inhalation of pollutants such as volatile organic compounds (VOCs) has been shown to have many side-effects on human health. A group referred to as BTEX (benzene, toluene, ethylbenzene and the three isomers of xylene) has been found to be potentially hazardous to environmental and human health [ 1 ]. Human exposure to BTEX, both through inhalation or ingestion, can have serious health impacts, such as neurological diseases, cancers, and teratogenic effects [ 2 , 3 , 4 ].…”

An improved method for BTEX extraction from charcoal

“…These results are comparable with some recently published data where the extraction of BTEX was performed with ASE instrumentation on environmental samples by using acetone or acetonitrile as solvents. 9,25 Notwithstanding many advanced new techniques have been proposed in the last few years for rapid extraction of COV, the classic Soxhlet 15 is however a simple and inexpensive tool that can encourage the substitution of carbon disulde with less hazardous solvents.…”

“…The techniques used for BTEX monitoring are usually based on their sorption in a tube (active or passive devices) which is lled with a suitable sorbing agent, usually activated charcoal, followed by solvent desorption with CS 2 and gas chromatographic determination. 7,8 In Italy, to the best of our knowledge, more than 95% of laboratories of environmental analysis follow this procedure notwithstanding alternative techniques are well known but not commonly used, among the others, thermal desorption and accelerated solvent extraction, 9 because of their high costs.…”

BTEXs in Indoor and Outdoor Air Samples: Source Apportionment and Health Risk Assessment of Benzene

“…BTEX refers to Benzene, Toluene, Ethyl benzene and three isomers of Xylene and they are referred by World Health Organization (WHO) as hazardous air pollutants (HAPs) [1]. Humans who are exposed to BTEX for a long period of time have high risk to chronic disease, such as cancer [2].…”