title: Portable gas chromatograph with tunable retention and sensor array detection for determination of complex vapor mixtures.
abstract: A prototype portable gas chromatograph that combines a multiadsorbent preconcentrator/focuser, a tandem-column separation stage with individual column temperature control and junction point pressure modulation, and a detector consisting of an integrated array of polymer-coated surface acoustic wave microsensors is described. Using scheduled first-column stop-flow intervals and independent temperature programming of the two columns, it is possible to adjust the retention of eluting analyte vapors to maximize vapor recognition with the microsensor array and minimize the time of analysis. A retention window approach is combined with Monte Carlo simulations to guide retention tuning requirements and facilitate pattern recognition analyses. The determination of a 30-vapor mixture of common indoor air contaminants in < 10 min is demonstrated using ambient air as the carrier gas. Detection limits of < 10 ppb are achieved for the majority of compounds from a 1-L air sample on the basis of the most sensitive sensor in the array. Performance is assessed in the context of near-real-time indoor air quality monitoring applications.
authors.affiliation: Department of Environmental Health Sciences, Center for Wireless Integrated MicroSystems, University of Michigan, Ann Arbor, Michigan 48109-2029, USA.
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Lu
authors.forename: Joshua
authors.initials: J
authors.lastname: Whiting
authors.forename: Richard D
authors.initials: RD
authors.lastname: Sacks
authors.forename: Edward T
authors.initials: ET
authors.lastname: Zellers
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D002849:Chromatography, Gas / Q000295:instrumentation*; D004867:Equipment Design; D005740:Gases / Q000032:analysis*; D009010:Monte Carlo Method; D009930:Organic Chemicals / Q000032:analysis; D010363:Pattern Recognition, Automated
chemical_list: D005740:Gases; D009930:Organic Chemicals