A new approach to determine vapor pressures of compounds in multicomponent systems by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.
A method is described to determine vapor pressures of compounds in multicomponent systems simultaneously. The method is based on temperature-gradient analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS). Vapor pressures are determined with the aid of known vapor pressure values of reference compounds eluting before and after the analytes. Reference compounds with the same functionalities as the analytes are preferred, but when these are not available, the alkane series can be utilized. The number of compounds whose vapor pressures can be determined is limited only by the peak capacity of the chromatographic system. Although the lowest subcooled vapor pressure determined was 0.006 Pa, for tetrahydroaraucarolone in an atmospheric aerosol sample, vapor pressures as low as 10(-6) Pa can be measured with the described set-up. Even lower values can be measured with higher GC temperatures and longer analysis times. Since only a few picograms of compound is required, in a mixture of any complexity, the GCxGC-TOFMS method offers unique sensitivity, rapidity, and comprehensiveness.
Laboratory of Analytical Chemistry, Department of Chemistry, PO Box 55, University of Helsinki, Helsinki, FI-00014, Finland. Electronic address: evgeny.parshintsev@helsinki.fi.
Jevgeni
J
Parshintsev
Laboratory of Analytical Chemistry, Department of Chemistry, PO Box 55, University of Helsinki, Helsinki, FI-00014, Finland.
Ching Kwan
CK
Lai
Laboratory of Analytical Chemistry, Department of Chemistry, PO Box 55, University of Helsinki, Helsinki, FI-00014, Finland.
Kari
K
Hartonen
Division of Atmospheric Sciences, Department of Physics, PO Box 64, University of Helsinki, Helsinki, FI-00014, Finland.
Markku
M
Kulmala
Laboratory of Analytical Chemistry, Department of Chemistry, PO Box 55, University of Helsinki, Helsinki, FI-00014, Finland. Electronic address: marja-liisa.riekkola@helsinki.fi.
Marja-Liisa
ML
Riekkola
Atmospheric aerosols; GCxGC-TOFMS; Gas chromatography; Multicomponent system; Temperature gradient; Vapor pressure