Compound-Specific Radiocarbon Analysis of Low Molecular Weight Dicarboxylic Acids in Ambient Aerosols Using Preparative Gas Chromatography: Method Development
Compound-Specific Radiocarbon Analysis of Low Molecular Weight Dicarboxylic Acids in Ambient Aerosols Using Preparative Gas Chromatography: Method Development
复制标题
使用制备型气相色谱法对环境气溶胶中的低分子量二羧酸进行化合物特异性放射性碳分析：方法开发
DOI：
10.1021/acs.estlett.0c00887
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发表时间：
2021
影响因子：
10.9
通讯作者：
Zhang Gan
中科院分区：
文献类型：
--
作者：
Xu Buqing;Cheng Zhineng;Gustafsson Örjan;Kawamura Kimitaka;Jin Biao;Zhu Sanyuan;Tang Tiangang;Zhang Bolong;Li Jun;Zhang Gan
低分子量二元酸构成了大气有机气溶胶的很大一部分，它们影响大气辐射强迫，从而影响地球气候。放射性碳(14C)是明确区分生物质来源和化石来源的相对贡献的独特方法。在这里，我们开发了一种化合物特异性放射性碳分析(CSRA)方法，用于大气颗粒物中单个二元酸的分析。具体地说，该方法从二丁酯衍生化技术开始，然后使用制备毛细管气相色谱分离和收获足够数量的单一化合物，以便用加速器质谱仪进行离线14C测量。在优化的制备步骤中，目标分子的回收率为60%，纯度为99%。通过整个方法测定的参比标准的放射性碳同位素组成与每个标准的原始组成非常吻合(R2=0.9998)。以代表不同气团状况的环境气溶胶样本为例，证明了该方法的适用性。这产生了两个截然不同但系统一致的前兆来源。要进行可靠的14C测量，至少需要50μg C的环境二元酸。建立的二元酸CSRA分析方法为研究大气二次有机气溶胶的来源和演化提供了一个新的分析维度。
Low molecular weight dicarboxylic acids constitute a large fraction of atmospheric organic aerosols, which impact atmospheric radiative forcing and hence Earth’s climate. Radiocarbon (14C) is a unique approach to unambiguously distinguishing the relative contributions of biomass-derived and fossil sources. Here, we developed a compound-specific radiocarbon analysis (CSRA) method for individual dicarboxylic acids in atmospheric particulates. Specifically, the method starts with a dibutyl ester derivatization technique, followed by separation and harvesting of single compounds employing a preparative capillary gas chromatography in sufficient amounts for offline14C measurement with accelerator mass spectrometry. The optimized preparative steps yielded recoveries of >60% and purities of >99% for target molecules. The radiocarbon isotope compositions determined for reference standards taken through the entire method agree well with the original composition of each standard (R2= 0.9998). The applicability of the approach was demonstrated with ambient aerosol samples representing contrasting air mass regimes. This yielded two radically different yet system-consistent precursor sources. A minimum size of 50 μg of C of ambient dicarboxylic acids is needed for credible14C measurement. The established method for CSRA of dicarboxylic acids demonstrates a new analytical dimension for studies of the source and evolution of atmospheric secondary organic aerosols.