Microfabricated Gas Chromatograph for the Selective Determination of Trichloroethylene Vapor at Sub-Parts-Per-Billion Concentrations in Complex Mixtures

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• 作者：Sun Kyu Kim ; Hungwei Chang ; Edward T. Zellers
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：September 15, 2011
• 年：2011
• 卷：83
• 期：18
• 页码：7198-7206
• 全文大小：921K
• 年卷期：v.83,no.18(September 15, 2011)
• ISSN：1520-6882

文摘

A complete field-deployable microfabricated gas chromatograph (渭GC) is described, and its adaptation to the analysis of low- and subparts-per-billion (ppb) concentrations of trichloroethylene (TCE) vapors in complex mixtures is demonstrated through laboratory testing. The specific application being addressed concerns the problem of indoor air contamination by TCE vapor intrusion. The 渭GC prototype employs a microfabricated focuser, dual microfabricated separation columns, and a microsensor array. These are interfaced to a nonmicrofabricated front-end pretrap and high-volume sampler module to reduce analysis time and limits of detection (LOD). Selective preconcentration and focusing are coupled with rapid chromatographic separation and multisensor detection for the determination of TCE in the presence of up to 45 interferences. Autonomous operation is possible via a laptop computer. Preconcentration factors as high as 500鈥?00 are achieved. Sensitivities are constant over the range of captured TCE masses tested (i.e., 9鈥?90 ng), and TCE is measured in a test atmosphere at 120 parts-per-trillion (ppt), with a projected LOD of 40 ppt (4.2 ng captured, 20 L sample) and a maximum sampling + analytical cycle time of 36 min. Short- and medium-term (1 month) variations in retention time, absolute responses, and response patterns are within acceptable limits.