BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) are volatile aromatic hydrocarbons found in petroleum derivates such as motor vehicle fuel. Once released to the environment, BTEX compounds usually evaporate quickly into the air. They are hazardous chemicals and their presence in ambient air has been the subject of great concern in many studies. The primary exposure to BTEX, in fact, is from breathing air contaminated by motor vehicles emissions, industrial use and cigarette smoke.
Due to the presence of a large amount of BTEX in ambient air at very low concentration (tipically from low ppb to high ppt), a preconcentration step followed by high-resolution gas chromatographic analysis is required to obtain enough sensitivity and resolution. Furthermore, the use of sorbent tubes provides an economical and versatile solution for concentrating apolar and polar volatile organics from air sample.