High-Speed Isothermal Analysis of Atmospheric Isoprene and DMS Using On-Line Two-Dimensional Gas Chromatography

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• 作者：Alastair C. Lewis ; Keith D. Bartle ; and Lauren Rattner
• 刊名：Environmental Science & Technology
• 出版年：1997
• 出版时间：November 1997
• 年：1997
• 卷：31
• 期：11
• 页码：3209 - 3217
• 全文大小：199K
• 年卷期：v.31,no.11(November 1997)
• ISSN：1520-5851

文摘

An instrument has been developed that allows rapidmeasurements of two of the most important volatile organicspecies in the atmosphere. The method utilizes two-dimensional gas chromatography coupled to a programmedtemperature vaporization injector used for sample preconcentration and injection. Attention is paid to thedetermination of atmospheric concentrations of isoprene (themost reactive hydrocarbon species) and dimethyl sulfide(DMS), the major source of sulfur in the marinetroposphereand a precursor to cloud formation. A sorbent packedlinerplaced inside a programmed temperature vaporizationinjector was held subambiently by means of a Peltierdeviceduring sample collection. Thermal desorption isperformedand the analytes passed to a primary column, separatingwith respect to analyte vapor pressure. Selectedlinearor "heart-cut" transfer is performed to a secondcolumnwhere the final separation is performed with respect tochemical functionality. Both primary and secondaryseparations are performed under isothermal conditions withcarrier pressure programming used to improve speed ofanalysis. Primary column backflush and concurrentsampleacquisition during the secondary analysis are also usedto keep analysis cycle times to a minimum. Total timeforsample collection and analysis is around 10 min, with aninstrument peak power consumption of 400 W and aminimum detectable limit of 5 ppt for isoprene and 25 pptfor DMS.