Microfabricated gas chromatograph for the selective determination of trichloroethylene vapor at sub-parts-per-billion concentrations in complex mixtures
| Autor: | Hungwei Chang, Edward T. Zellers, Sun Kyu Kim |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Detection limit
Chromatography Chromatography Gas Trichloroethylene Indoor air Chemistry 010401 analytical chemistry Parts-per notation Analytical chemistry 02 engineering and technology Contamination 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Analytical Chemistry Chromatographic separation chemistry.chemical_compound Air Pollution Indoor Vapor intrusion Gas chromatography Dimethylpolysiloxanes Gases 0210 nano-technology Environmental Monitoring |
| Zdroj: | Analytical chemistry. 83(18) |
| ISSN: | 1520-6882 |
| Popis: | A complete field-deployable microfabricated gas chromatograph (μGC) 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 μGC 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 500 000 are achieved. Sensitivities are constant over the range of captured TCE masses tested (i.e., 9-390 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. |
| Databáze: | OpenAIRE |
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