Journal of Chromatography A, 1216 (2009) 6063–6070 Contents lists available at ScienceDirect Journal of Chromatography A journal homepage: www.elsevier.com/locate/chroma Programmed temperature vaporizer based method for the sensitive determination of trihalomethanes and benzene, toluene, ethylbenzene and xylenes in soils José Luis Pérez Pavón ∗ , Sara Herrero Martín, Carmelo García Pinto, Bernardo Moreno Cordero Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain article info Article history: Received 16 February 2009 Received in revised form 16 June 2009 Accepted 18 June 2009 Available online 23 June 2009 Keywords: Headspace analysis Programmed temperature vaporizers Soil matrices Trihalomethanes BTEX abstract A methodology based on the coupling of a headspace autosampler with a GC and a MS detector operating in SIM mode has been developed for the determination of volatile organic compounds (THMs and BTEX) in soils. The GC device used is equipped with a programmable temperature vaporizer (PTV) packed with Tenax-TA ® to introduce the samples (the injection mode used was solvent vent), and a modular accel- erated column heater (MACH TM ) to control column temperature. The proposed measurement procedure reduces the sample pretreatment step to a minimum. Combined use of solvent vent injection mode and mass spectrometry detection allows a highly sensitive method to be proposed, with limits of detection of the order of ng/kg for all the target compounds. Furthermore, the capillary column used allows rapid separations of compounds in less than 4.60 min, affording a very short total analysis cycle time of 9 min. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Volatile organic compounds (VOCs) are widespread in the dif- ferent environmental matrices. The soil is one of the more sensitive and vulnerable receptors for this type of compounds. Additionally, pollution agents in the soil can be readily transferred to the atmo- sphere and underground waters [1]. Many such compounds and their degradation products are either known or suspected of being toxic and carcinogenic, such that they pose a severe risk to human health and ecosystems. These factors underscore the need for normative instruments that will ensure the protection of soils, establish their use, and fix the concentration levels for each of the VOCs above which a soil should be considered polluted. Accordingly, the development of analytical methods able to determine trace concentrations of VOCs in soils in a rapid, simple and reliable way is paramount. This type of analysis has usually been performed by extraction of VOCs from soil and quantification by gas chromatography (GC), followed by mass spectrometry (MS), flame ionization detection (FID) and, in the case of halogenated compounds, electron capture detection (ECD) [2]. The most critical step in the method is com- pound extraction. This is due to the diversity and complexity of the samples and to the low concentrations and high volatility of ∗ Corresponding author. Fax: +34 923 294483. E-mail address: jlpp@usal.es (J.L.P. Pavón). the compounds. A broad variety of extraction procedures has been proposed [3–5]. Classical solvent extraction techniques such as Soxhlet extrac- tion [6–8] and liquid–solid extraction [6,9] are usually time- consuming, multi-step procedures, require large volumes of organic solvents, and often require a lot of extract manipulation. Over the past few years, new technologies that use less solvent and are faster than classical procedures have been applied to the determination of VOCs in soils. Some examples are: supercritical fluid extraction (SFE) [10] and pressurised liquid extraction (PLE) [7], which have usually been applied in the determination of semi-volatile com- pounds in soils [11–15], or microwave-assisted extraction (MAE) [16,17] or ultrasonic solvent extraction. The advantage of these techniques is that they are not very matrix-dependent since they achieve almost complete extraction of the analytes. However, an important drawback is that they usually need additional cleaning and enrichment steps of the extracts obtained and are therefore car- ried out off-line [12]. Recently, a technique called Stir Bar Sorptive Extraction (SBSE) has been combined with these solvent extraction methods in the determination of semi-volatile compounds in soils [18–21]. The compounds are adsorbed and preconcentrated in the Stir Bar and then are analyzed by thermal desorption (TD)-GC. The technique has proved to avoid tedious clean-up and preconcentra- tion steps, have higher throughput capacity and improve detection limits. Headspace techniques have also been widely applied. Static headspace (HS) [22] and purge and trap (P&T) [23] are, together 0021-9673/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2009.06.057