35. The analysis of ambient particular matter (PM 2.5) by two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOF MS).

(1)Institute of Ecological Chemistry, GSF-Research Centre, D-85764 Oberschleißheim, Germany

*(2)Analytical Chemistry, University of Augsburg, D-86159 Augsburg, Germany

(3)BIFA - Bavarian Institute of Applied Environmental Research and Technology, D-86167 Augsburg, Germany

The use of GCxGC-TOF MS in the analysis of the organic content of ambient aerosols was investigated. GCxGC-TOFMS is a suited technique (due to increased peak capacities relative to normal GC) to analyze complex samples consisting of thousands of compounds. Combining GCxGC with mass spectrometry creates even more advantages. These advantages include enhanced peak identification since GCxGC provides better separation of compounds allowing compound mass spectra with low matrix noise. Compounds are also amplified due to the refocusing in the modulator, and with improved resolution deconvolution algorithms can identify compounds with better library matches. The amount of data generated is, however, getting enormously complex. Hundreds of peaks are revealed with each having a deconvoluted mass spectrum. In a PM 2.5 (particular matter of up to 2.5 mm) sample from Augsburg more than 15 000 peaks can be detected. Thus it is important to classify the observed GCxGC peaks by rational means. A classification procedure based on GCxGC retention times and the fragmentation patterns is suggested. With the proposed classification procedure it is already possible to group compounds with some certainty into substance classes. With some further development this approach can be used for classifying GCxGC data e.g. for environmental and epidemiological studies.