title: Simple and accurate quantification of BTEX in ambient air by SPME and GC-MS.
abstract: Benzene, toluene, ethylbenzene and xylenes (BTEX) comprise one of the most ubiquitous and hazardous groups of ambient air pollutants of concern. Application of standard analytical methods for quantification of BTEX is limited by the complexity of sampling and sample preparation equipment, and budget requirements. Methods based on SPME represent simpler alternative, but still require complex calibration procedures. The objective of this research was to develop a simpler, low-budget, and accurate method for quantification of BTEX in ambient air based on SPME and GC-MS. Standard 20-mL headspace vials were used for field air sampling and calibration. To avoid challenges with obtaining and working with 'zero' air, slope factors of external standard calibration were determined using standard addition and inherently polluted lab air. For polydimethylsiloxane (PDMS) fiber, differences between the slope factors of calibration plots obtained using lab and outdoor air were below 14%. PDMS fiber provided higher precision during calibration while the use of Carboxen/PDMS fiber resulted in lower detection limits for benzene and toluene. To provide sufficient accuracy, the use of 20mL vials requires triplicate sampling and analysis. The method was successfully applied for analysis of 108 ambient air samples from Almaty, Kazakhstan. Average concentrations of benzene, toluene, ethylbenzene and o-xylene were 53, 57, 11 and 14µgm(-3), respectively. The developed method can be modified for further quantification of a wider range of volatile organic compounds in air. In addition, the new method is amenable to automation.
authors.affiliation: Al-Farabi Kazakh National University, Faculty of Chemistry and Chemical Engineering, Center of Physical Chemical Methods of Research and Analysis, Almaty, Kazakhstan. Electronic address: baimatova@cfhma.kz.
authors.forename: Nassiba
authors.initials: N
authors.lastname: Baimatova
authors.affiliation: Al-Farabi Kazakh National University, Faculty of Chemistry and Chemical Engineering, Center of Physical Chemical Methods of Research and Analysis, Almaty, Kazakhstan. Electronic address: bkenesov@cfhma.kz.
authors.forename: Bulat
authors.initials: B
authors.lastname: Kenessov
authors.affiliation: Iowa State University, Department of Agricultural and Biosystems Engineering, Ames, IA 50011, USA. Electronic address: koziel@iastate.edu.
authors.forename: Jacek A
authors.initials: JA
authors.lastname: Koziel
authors.affiliation: Awareness Center, Trekroner, DK-4000 Roskilde, Denmark. Electronic address: LC@AwarenessCenter.dk.
authors.forename: Lars
authors.initials: L
authors.lastname: Carlsen
authors.affiliation: Al-Farabi Kazakh National University, Faculty of Chemistry and Chemical Engineering, Center of Physical Chemical Methods of Research and Analysis, Almaty, Kazakhstan.
authors.forename: Marat
authors.initials: M
authors.lastname: Bektassov
authors.affiliation: Al-Farabi Kazakh National University, Faculty of Chemistry and Chemical Engineering, Center of Physical Chemical Methods of Research and Analysis, Almaty, Kazakhstan.
authors.forename: Olga P
authors.initials: OP
authors.lastname: Demyanenko
mesh_terms: D001554:Benzene; D001555:Benzene Derivatives; D001557:Benzenesulfonates; D008401:Gas Chromatography-Mass Spectrometry; D052617:Solid Phase Microextraction; D014050:Toluene; D014992:Xylenes
chemical_list: D001555:Benzene Derivatives; D001557:Benzenesulfonates; D014992:Xylenes; C056082:4-sulfophenylmethallyl ether; D014050:Toluene; D001554:Benzene
keywords: Air analysis; Ambient air pollution; BTEX; GC–MS; Solid-phase microextraction; Standard addition