Validation of Atmospheric VOC Measurements by Proton-Transfer- Reaction Mass Spectrometry Using a Gas-Chromatographic Preseparation Method

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• 作者：Carsten Warneke ; Joost A. de Gouw ; William C. Kuster ; Paul D. Goldan ; and Ray Fall
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：June 1, 2003
• 年：2003
• 卷：37
• 期：11
• 页码：2494 - 2501
• 全文大小：192K
• 年卷期：v.37,no.11(June 1, 2003)
• ISSN：1520-5851

文摘

Proton-transfer-reaction mass spectrometry (PTR-MS) hasemerged as a useful tool to study volatile organiccompounds (VOCs) in the atmosphere. In PTR-MS, proton-transfer reactions with H₃O⁺ ions are used to ionize andmeasure VOCs in air with a high sensitivity and fast timeresponse. Only the masses of the ionized VOCs and theirfragments, if any, are determined, and these product ions arenot unique indicators of VOC identities. Here, a combinationof gas chromatography and PTR-MS (GC-PTR-MS) isused to validate the measurements by PTR-MS of a numberof common atmospheric VOCs. We have analyzed 75VOCs contained in standard mixtures by GC-PTR-MS, whichallowed detected masses to be unambiguously relatedto a specific compound. The calibration factors for PTR-MS and GC-PTR-MS were compared and showed that theloss of VOCs in the sample acquisition and GC system issmall. GC-PTR-MS analyses of 56 air samples from an urbansite were used to address the specificity of PTR-MS incomplex air masses. It is demonstrated that the ions associatedwith methanol, acetonitrile, acetaldehyde, acetone,benzene, toluene, and higher aromatic VOCs are freefrom significant interference. A quantitative intercomparisonbetween PTR-MS and GC-PTR-MS measurements of theaforementioned VOCs was performed and shows that theyare accurately measured by PTR-MS.