Articles | Volume 3, issue 3
Atmos. Chem. Phys., 3, 665–682, 2003

Special issue: Mediterranean intensive oxidant study (MINOS 2001)

Atmos. Chem. Phys., 3, 665–682, 2003

  10 Jun 2003

10 Jun 2003

Comprehensive two-dimensional gas chromatography (GC × GC) measurements of volatile organic compounds in the atmosphere

X. Xu1, L. L. P. Stee2, J Williams1, J. Beens2, M. Adahchour2, R. J. J. Vreuls2, U. A. Brinkman2, and J. Lelieveld1 X. Xu et al.
  • 1Max Planck Institute for Chemistry, Mainz, Germany
  • 2Department of Analytical Chemistry and Applied Spectroscopy, Free University Amsterdam, The Netherlands

Abstract. During the MINOS campaign in August 2001 comprehensive two-dimensional gas chromatography (GC x GC) was applied to the in situ measurements of atmospheric volatile organic compounds (VOCs) at the Finokalia ground station, Crete. The measurement system employs a thermal desorption unit for on-line sampling and injection, and a GC x GC separation system equipped with a flame ionization detector (FID) for detection. The system was optimized to resolve C7-C14 organic components. Two-dimensional chromatograms from measurements of Finokalia air samples show several hundred well-separated peaks. To facilitate peak identification, cartridge samples collected at Finokalia were analyzed using the same GC x GC system coupled with a time-of-flight mass spectrometer (TOF-MS). The resulting mass spectra were deconvoluted and compared to spectra from a database for tentative peak identification. About 650 peaks have been identified in the two-dimensional plane, with significant signal/noise ratios (>100) and high spectra similarities (>800). By comparing observed retention indices with those found in the literature, 235 of the identifications have been confirmed. 150 of the confirmed compounds show up in the C7-C14 range of the chromatogram from the in situ measurement. However, at least as many peaks remain unidentified. For quantification of the GC x GC measurements, peak volumes of measured compounds have been integrated and externally calibrated using a standard gas mixture.

Final-revised paper