title: Microfabricated gas chromatograph for rapid, trace-level determinations of gas-phase explosive marker compounds.
abstract: A prototype microfabricated gas chromatograph (μGC) adapted specifically for the rapid determination of selected gas-phase marker compounds of the explosive 2,4,6-trinitrotoluene (TNT) at sub-parts-per-billion (<ppb) concentrations in complex mixtures is described. Si-microfabricated focuser, separation column, and sensor array components are integrated with a high-volume sampler of conventional construction to reduce analysis time and the limit of detection (LOD). The primary markers selected as target analytes were 2,4-dinitrotoluene (2,4-DNT, a persistent impurity of TNT) and 2,3-dimethyl-2,3-dinitrobutane (DMNB, a taggant), along with 2,6-dinitrotoluene (2,6-DNT, a less-prominent TNT impurity), which was also included in numerous tests. Selective preconcentration, on-column focusing, temperature-programmed chromatographic separation, and sensor array detection/recognition facilitated determinations of the primary markers in the presence of 20 (or more) interferences within ∼2 min under laptop control. Estimated LODs of 2.2, 0.48, and 0.86 ng were achieved for DMNB, 2,6-DNT, and 2,4-DNT, respectively, which correspond to 0.30, 0.067, and 0.12 ppb in each 1-L air sample collected.
authors.affiliation: Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109-1055, United States.
authors.forename: William R
authors.initials: WR
authors.lastname: Collin
authors.forename: Gustavo
authors.initials: G
authors.lastname: Serrano
authors.forename: Lindsay K
authors.initials: LK
authors.lastname: Wright
authors.forename: Hungwei
authors.initials: H
authors.lastname: Chang
authors.forename: Nicolás
authors.initials: N
authors.lastname: Nuñovero
authors.forename: Edward T
authors.initials: ET
authors.lastname: Zellers