Combination of Cryotrapping and SPME for GC/MS Analysis

An improved process has been devised for acquiring and preparing trace amounts of airborne organic compounds for analysis by a gas chromatograph and mass spectrometer (GC/MS). A sample of air is passed through a cryotrap, where organic compounds and water vapor condense on the wall of a tube cooled by liquid nitrogen or dry ice. The condensed material is diluted to a known volume in a sample bottle. An aliquot is taken from the sample bottle. A solid-phase-microextraction (SPME) fiber (a silica fiber coated with a thin layer of material that adsorbs the organic compounds of interest) is placed in the aliquot to absorb the analyte. The SPME fiber is placed in the injection port of the GC/MS and heated to desorb the analyte onto a cool column. Heretofore, cryotrapping of water has been problematic in sampling for GC/MS, but this process uses cryotrapping of water as an advantage and enables solvent-free injection with minimal preparation of samples. In comparison with older GC/MS sampling processes, this process is faster, utilizes samples more efficiently, and is amenable to sampling of larger volumes of air without concern about water.