Two Dimensional Chromatography of Atmospheric Aerosols: A New In-Situ Instrument

Organic matter is a major constituent of airborne particles, comprising 20-50% of their mass. Identification of its components is critical for tracing sources, elucidating transformation and formation processes, assessing affects on human health, and assessing affects on global climate. Therefore, in situ, high-time-resolution comprehensive measurements of organic aerosol speciation are required. In previous work, a Thermal Desorption Aerosol Gas Chromatography (TAG) Mass Spectrometer (MS) was developed, which provides identification and quantification of organic constituents at the molecular level, with hourly in situ measurements. Although many compounds can be identified with TAG, a significant portion of the material eluting from the single dimension chromatography column is not separated. Therefore, this project will improve the chromatographic resolution of the TAG by using two-dimensional (2D) chromatography, thereby allowing a vastly increased number of individual organic species in ambient aerosols to be measured. Phase I successfully incorporated a 2D chromatography system onto the existing 1D-TAG system. A considerable improvement in the separation of organic compounds, in both complex standards and ambient aerosols, was demonstrated. The 2D-TAG was able to separate more than 6 times as many compounds as the 1D-TAG. In Phase II, a fast mass spectrometry capability will be added to the 2D-TAG, and the chromatography will be refined to enhance the separation of individual organic compounds. The complete 2D-TAG-MS system will be tested, along with traditional filter-based methods and a variety of complementary measurement system.Commercial Applications and other Benefits as described by the awardee: Beyond the on-line chemical analysis of aerosols for atmospheric research, the technology should be applicable to drug manufacturing and to the detection of biological or chemical agents related to homeland defens