Sorbent-Based Method for the Analysis of Ambient Air Using Supercritical Fluid Desorption/Gas Chromatography

摘要

The work described in this paper shows how we have investigated the utility of polar polyimide sorbents for the collection of polar and non-polar volatile organic compounds in ambient air. The results indicate that supercritical carbon dioxide can be used to recover a variety of compounds with a wide range of volatilities from polyimide sorbents and that these compounds can be effectively collected onto an adsorbent micro-trap after the expansion of the fluid prior to thermal desorption gas chromatographic analysis. Molecular sieve 3A was used and found to have a very high capacity for removal of water from the supercritical fluid extract stream. The sieve tended to adsorb polar compounds in the absence of water; the presence of water sometimes reduced analyte adsorption. The method was used to collect, recover, and analyze volatile organic compounds from the air of a laboratory building and was shown to be quite sensitive for appropriate compounds.