Physico-chemical characterization of SOA derived from catechol and guaiacol - a model substance for the aromatic fraction of atmospheric HULIS
Physico-chemical characterization of SOA derived from catechol and guaiacol - a model substance for the aromatic fraction of atmospheric HULIS
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DOI：
10.5194/acp-11-1-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Zetzsch, C.
中科院分区：
文献类型：
--
作者：
Ofner, J.;Krueger, H. -U.;Zetzsch, C.
二次有机气溶胶（SOA）产生的芳香族前体邻苯二酚和愈创木酚与臭氧在模拟的阳光和湿度的存在和不存在下的反应，并研究其作为类腐殖酸物质（HULIS）的代理的属性。除了小的颗粒尺寸、相对低的分子量和UV/维斯光谱范围内的典型光学特征之外，HULIS还含有典型的芳香族和/或烯烃化学结构和高度氧化的官能团，具有高度的化学多样性。各种方法被用来表征所获得的二次有机气溶胶：傅里叶变换红外光谱（FTIR）证明了几个羰基含官能团的形成，以及在不同的环境条件下形成的气溶胶之间的结构和功能差异。过滤器样品的UV/维斯光谱显示，微粒物质吸收远至超过500 nm的可见光范围。超高分辨质谱法（ICR-FT/MS）确定O/C比在0.3和1之间，并观察到m/z比在200和450之间是最丰富的。程序升温热解质谱（TPP-MS）确定羧酸和内酯/酯为主要官能团。使用凝聚核计数器和微分迁移率粒度仪（CNC/DMPS）的粒度测量监测SOA形成过程中小颗粒的形成。粒子成像，使用场发射枪扫描电子显微镜（FEG-SEM），显示球形粒子，形成集群和链。我们的结论是邻苯二酚和愈创木酚是合适的前体研究的芳香SOA与大气HULIS性能在实验室规模上的加工。
Secondary organic aerosol (SOA) was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for HUmic-LIke Substances (HULIS). Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR) demonstrated the formation of several carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS) determined O/C-ratios between 0.3 and 1 and observed m/z ratios between 200 and 450 to be most abundant. Temperature-programmed-pyrolysis mass spectroscopy (TPP-MS) identified carboxylic acids and lactones/esters as major functional groups. Particle sizing using a condensation-nucleus-counter and differential-mobility-particle-sizer (CNC/DMPS) monitored the formation of small particles during the SOA formation process. Particle imaging, using field-emission-gun scanning electron microscopy (FEG-SEM), showed spherical particles, forming clusters and chains. We conclude that catechol and guaiacol are appropriate precursors for studies of the processing of aromatic SOA with atmospheric HULIS properties on the laboratory scale.