Abstract
Current standard approaches for quantitation of volatile organic compounds (VOCs) in outdoor air are labor-intensive and/or require additional equipment. Solid-phase microextraction (SPME) is a simpler alternative; however, its application is often limited by complex calibration, the need for highly pure gases and the lack of automation. Earlier, we proposed the simple, automated and accurate method for quantitation of benzene, toluene, ethylbenzene and xylenes (BTEX) in air using 20 mL headspace vials and standard addition calibration. The aim of present study was to expand this method for quantitation of >20 VOCs in air. Twenty-five VOCs were chosen for the method development. Polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber provided better combination of detection limits and relative standard deviations of calibration slopes than other studied fibers. Optimal extraction time was 10 min. For quantification of all analytes except n-undecane, crimp top vials with samples should not stand on the autosampler tray for >8 h, while 22 most stable analytes can be quantified during 24 h. The developed method was successfully tested for automated quantification of VOCs in outdoor air samples collected in Almaty, Kazakhstan. Relative standard deviations (RSDs) of the responses of 23 VOCs were below 15.6%. Toluene-to-benzene concentration ratios were below 1.0 in colder days, indicating that most BTEX originated from non-transport-related sources.
Highlights
The pollution of ambient and indoor air are the main sources of risk to human health in the world [1]
Current standard sampling approaches for quantification of volatile organic compounds (VOCs) in air [2,3,4] are mainly based on collecting air samples into evacuated canisters [2,5] or trapping analytes onto sorbent tubes [3,6] followed by the analysis on a gas chromatograph (GC) with a chosen detector, mostly being flame-ionization (FID) or mass spectrometry (MS)
Air sampling by standard methods based, e.g., on sorbent tubes [2,3], requires additional equipment such as an air sampling pump and a thermal desorption system connected to a gas chromatograph
Summary
The pollution of ambient and indoor air are the main sources of risk to human health in the world [1]. Current standard sampling approaches for quantification of VOCs in air [2,3,4] are mainly based on collecting air samples into evacuated canisters [2,5] or trapping analytes onto sorbent tubes [3,6] followed by the analysis on a gas chromatograph (GC) with a chosen detector, mostly being flame-ionization (FID) or mass spectrometry (MS). Despite good reliability, these sampling techniques [4] are quite complex, labor- and time-consuming, as well as requiring additional equipment. In order to solve these problems, it is necessary to reduce the volume of organic solvents used for extraction, or completely exclude them; fully or Separations 2019, 6, 51; doi:10.3390/separations6040051 www.mdpi.com/journal/separations
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