Fast field sampling/sample preparation and quantification of volatile organic compounds in indoor air by solid-phase microextraction and portable gas chromatography

Abstract

Solid-phase microextraction (SPME) was used as a rapid, simple, convenient, and cost-effective technique to sample volatile organic compounds (VOCs) in indoor air. Concentrations of five target VOCs, including benzene, toluene, ethylbenzene, m,p-xylenes, and hexane, were determined on site in several buildings around the city of Waterloo, Canada. Samples were collected with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) porous polymer-coated fiber and 1-min sampling time, followed by 15-min analysis. Fast separation and speciation of common indoor air pollutants was possible with the use of a modified, SRI portable gas-chromatography (GC) instrument, equipped with a photoionization (PID), a flame ionization (FID), and a dry electrolytic conductivity detector (DELCD) in series. The mass calibration for target VOCs was based on the diffusion-controlled extraction onto the adsorptive SPME coating. The method detection limits for the target VOCs in air were between one and nine parts per billion (ppb). Target VOC concentrations measured with SPME/fast GC were comparable to those obtained with the National Institute of Occupational Safety and Health (NIOSH) 1501 method. The use of SPME coupled to a portable GC instrument allowed for at least a tenfold reduction of the total sampling and analysis time. The short SPME sampling time combined with fast, portable GC provided a near-real-time measurement of target VOCs. The results suggest that fast air sampling with adsorptive SPME fibers can be used for analyte speciation based on diffusion coefficients. The combination of SPME and a portable fast GC proved to be a very promising technique for conducting cost-effective indoor air quality surveys and making on-site decisions to control VOC emissions. © 2000 John Wiley & Sons, Inc. Field Analyt Chem Technol 4: 73–84, 2000