Characterization of Polar Compounds and Oligomers in Secondary Organic Aerosol Using Liquid Chromatography Coupled to Mass Spectrometry

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• 作者：Jacqueline F. Hamilton ; Alastair C. Lewis ; Trevor J. Carey ; John C. Wenger
• 刊名：Analytical Chemistry
• 出版年：2008
• 出版时间：January 15, 2008
• 年：2008
• 卷：80
• 期：2
• 页码：474 - 480
• 全文大小：157K
• 年卷期：v.80,no.2(January 15, 2008)
• ISSN：1520-6882

文摘

A generic method has been developed for the analysis ofpolar compounds and oligomers in secondary organicaerosol (SOA) formed during atmospheric simulationchamber experiments. The technique has been successfully applied to SOA formed in a variety of systems,ranging from ozonolysis of biogenic volatile organic compounds to aromatic photooxidation. An example application of the method is described for the SOA producedfrom the reaction of ozone with cis-3-hexenyl acetate, animportant biogenic precursor. A range of solvents weretested as extraction media, and water was found to yieldthe highest recovery. Extracts were analyzed using reversed-phase liquid chromatography coupled to ion trapmass spectrometry. In order to determine correct molecular weight assignments and increase sensitivity for lesspolar species, a series of low-concentration mobile-phaseadditives were used (NaCl, LiBr, NH₄OH). Lithium bromide produced better fragmentation patterns, with morestructural information than in the other cases with noreduction in sensitivity. The main reaction productsidentified in the particle-phase were 3-acetoxypropanal,3-acetoxypropanoic acid, and 3-acetoxypropane peroxoicacid and a series of dimers and trimers up to 500 Da.Structural identification of oligomers indicates the presence of linear polyesters possibly formed via esterficationreactions or decomposition of peroxyhemiacetals.