In-injection port thermal desorption and subsequent GC-MS analysis of PAHs, alkanes, hopanes, and steranes in atmospheric aerosol samples

The traditional approach for analysis of aerosol organics is to extract aerosol materials collected on filter substrates with organic solvents followed by solvent evaporation and analytical separation and detection. This approach has the weaknesses of being labor intensive and being prone to contamination from the extracting solvents. We describe here an alternative approach, which obviates the use of solvents, for the analysis of nonpolar organic compounds in aerosol samples, including polycyclic aromatic hydrocarbons (PAHs), alkanes, hopanes, and phthalates. In our approach, small strips of aerosol-laden filter materials are packed into a GC split/splitless injector liner. Nonpolar organics on the filter are thermally desorbed in the injection port and focused onto the head of a GC column for subsequent separation and detection. No instrument modification is necessary to accommodate the introduction of the aerosol organics into the GC-MS system. Examples are given to illustrate the use of this method in the analysis of ambient aerosol samples.