Determination of BTEX Compounds in Ambient Air Using Solid Phase Microextraction Gas Chromatography-Mass Spectrometry

Christopher L. Marcum1; Bert C. Lynn2

1. Department of Chemistry, Eastern Kentucky University, Richmond, KY2. Department of Chemistry, University of Kentucky, Lexington KY

Introduction

Experimental Methods

Results and Discussion Conclusions

Future Work

Acknowledgements

We are grateful to the Department of Chemistry, University of Kentucky REU program, funded by NSF and the Air Force ASSURE program for support of this work.

SPME Fiber

Septum Piercing NeedleBarrelPlunger

Cutaway view of SPME fiber in manual holder

Air quality is of paramount importance. Exposure to air which contains contaminants can lead to major health problems including nervous system damage.Recently, solid phase microextraction (SPME) has been offered as an alternative to traditional air sampling techniques for determination of air contaminants.The purpose of our study is to develop a technique for the determination of BTEX compounds (benzene, toluene, ethylbenzene, xylenes) in ambient indoor air using SPME, coupled with gas chromatography/mass spectrometry (GC/MS).Evidence also shows a possible link between these BTEX contaminants and electronic equipment, such as laser printers and copiers.

Air sampling was accomplished through the use of a carboxen/PDMS SPME fiber placed in a manual holder. Before sampling, each fiber was conditioned for 2 hours in a hot GC injection port.

Several locations were sampled across the campus of the University of Kentucky, Lexington, KY:

Chemistry Department Copy Room, Chemistry Physics BuildingChemistry Department Office, Chemistry-Physics BuildingIntellectual Property Office, Advanced Science and Technology Commercialization Center (ASTeCC) BuildingCopy/Fax Room, ASTeCC BuildingConference Room, ASTeCC BuildingOutside the ASTeCC Building

Fibers were transported to and from sample locations in clean glass tubes. Each sample fiber had an associated trip blank, which was not exposed to the air.Immediately following sampling, analysis of the fibers was carried out via a Varian 3400 4D GC/MS equipped with electron ionization and an ion trap mass analyzer.The effects of a laser printer on air quality were determined by enclosing a laser printer in a nitrogen filled glove bag and sampling the air in the bag while the printer was in several configurations: off, on without toner, and while printing.

The chromatogram (top) is from a SPME fiber exposed for 6 hours in the chemistry department copy room. The peaks labeled A-D were identified as the BTEX compounds shown above. Chromatograms were obtained from each location and the peak areas were examined in order to compare the locations.

SPME proved to be a very simple technique for air sampling and, when coupled with GC/MS, was very sensitive and selective for volatile organic compounds, including BTEX compounds.Although concentrations were not determined, the chemistry copy room, chemistry office, and intellectual property office had the highest levels of contamination from BTEX compounds.We found no observable link between either the presence or the use of a laser printer and an increase in BTEX compounds in the air. We also were unable to link the presence of a copy machine to an increase in BTEX contamination.

Analysis of other locations, including other campus buildings and perhaps some off-campus locationsUse of other traditional air sampling techniques to verify SPME resultsDetermine the concentration of BTEX compounds in each sample locationTesting of other possible sources of BTEX contamination using glove bag techniques

BenzenetR=1.75 min

CH3ToluenetR= 2.65 min

CH3EthylbenzenetR= 3.71 min

m-Xylene and/or p-XylenetR= 3.83 min

CH3

CH3

CH3

CH3

1 – Chemistry Copy Room2 – Chemistry Office3 – Intellectual Property Office4 – ASTeCC Copy Room5 – ASTeCC Conference Room6 – Outside ASTeCC

1 – Nitrogen Only2 – Printer Off3 – Printer On4 – Printer Printing

The peak areas for BTEX compounds were much greater in the chemistry copy room, chemistry office and intellectual property office.

Peak areas for BTEX compounds did not increase within an enclosed glove bag when a laser printer was introduced, turned on, or printing.

We would also like to thank the University of Kentucky Mass Spectrometry Facility and Michael Timmons for their assistance with this project.