Multi-adsorbent preconcentration/focusing module for portable-GC/microsensor-array analysis of complex vapor mixtures.
Analyst 2002 Aug; 127(8):1061-1068
A small multi-adsorbent preconcentration/focusing module for a portable GC with microsensor-array detector designed to determine complex mixtures of volatile and semi-volatile organic compounds encountered in indoor working environments is described. Candidate adsorbents were assessed on the basis of analyte thermal-desorption bandwidth and efficiency, chromatographic peak shape, and breakthrough volume against mixtures of organic compounds ranging over four orders of magnitude in vapor pressure. A capillary packed with just 12.3 mg of adsorbent material comprising Carbopack B (8 mg), Carbopack X (2.5 mg) and Carboxen 1000 (1.8 mg) provided the best tradeoff in operating variables, while maintaining sufficient capacity for a 1 L air sample containing a mixture of up to 43 compounds, each at 100 parts-per-billion, at an ambient relative humidity of up to 100%. On-column focusing and temperature programming were used to enhance chromatographic separations, and detection limits as low as 100 parts-per-trillion were achieved for a 1 L air sample using an integrated array of polymer-coated surface-acoustic-wave (SAW) sensors. Implications for field analysis of indoor air quality are emphasized.
Gas-chromatography; Vapors; Air-quality; Air-quality-monitoring; Air-quality-measurement; Gases; Organic-chemicals; Air-quality-control; Organic-compounds; Organic-vapors
Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2029
University of Michigan, Ann Arbor