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.

An analytical method for the analysis of trihalomethanes in ambient air using solid‐phase microextraction gas chromatography‐mass spectrometry: An application to indoor swimming pool complexes

“…Samples/standards were fortified with internal standard (final concentration of 25 µg/m 3 , added as 1 µL in methanol) prior to GC analysis. The advantages and applicability of the standard addition method for calibration for air analysis using glass vials and SPME have previously been demonstrated …”

“…The advantages and applicability of the standard addition method for calibration for air analysis using glass vials and SPME have previously been demonstrated. 38 utes, heated to 160ºC at 8°C/min, heated to 300°C at 25ºC/min, and held at 300°C for 5 minutes (total time 26 minutes). Selective ion monitoring (SIM) was used for analyte identification and quantification using mass-to-charge (m/z) ratios provided in Table S2.…”

Recent Applications and Newly Developed Strategies of Solid-Phase Microextraction in Contaminant Analysis: Through the Environment to Humans

“…Established pollutants such as polycyclic aromatic hydrocarbons (PAHs), and other hazardous substances including phthalates, adipates, vulcanizing agents and antioxidants were successfully analyzed in the air generated above synthetic turf football fields following heating of the rubber material using a PDMS/DVB as fiber coating in headspace mode [8]. Benzene, toluene, ethylbenzene, and xylenes (BTEX) in ambient air have been the target of one research with the aim of developing a simpler, low-budget, and accurate method for their quantification based on SPME and gas chromatography coupled with mass spectrometry (GC-MS) [9]. This article shows how in urban areas with highly contaminated air, 20 mL vials can be used for the collection of air samples, and a 100 µm polydimethylsiloxane (PDMS) fiber can be used to sufficiently preconcentrate the analytes before the analysis with GC-MS.…”

Low-Cost Quantitation of Multiple Volatile Organic Compounds in Air Using Solid-Phase Microextraction

“…Most methods require using high-purity gases for preparation of calibration samples, which can be difficult to purchase and prepare. Baimatova et al [25] developed a very simple, automated and accurate method for quantification of BTEX using SPME and successfully applied it for the analysis of ambient air in Almaty, Kazakhstan. Sampling was conducted with 20 mL crimp top vials, which were transported to the laboratory, located on the Combi PAL (CTC Analytics, Switzerland) autosampler tray and automatically analyzed using GC-MS. To simplify the method, the authors used standard addition calibration, which did not require any additional equipment and pure gases.…”