College of Chemistry, Advanced Energy Materials Chemistry (Ministry of Education), State Key Laboratory and Institute of Elemento-Organic Chemistry, Renewable Energy Conversion and Storage Center (ReCAST), Nankai University, Tianjin 300071, China.
J Am Soc Mass Spectrom. 2021 Sep 1;32(9):2306-2312. doi: 10.1021/jasms.1c00022. Epub 2021 Feb 9.
The photochemistry of α-keto acids has been of great interest due to its implications in atmospheric and prebiotic chemistries. α-Keto acids with long alkyl chains are amphiphilic in nature, and they tend to partition at the air-water interface of atmospheric water droplets and add to the complexity of the chemistries therein. The air-water interface is a unique environment that plays a vital role in overall atmospheric processes. However, existing studies mostly focus on the photochemistry of α-keto acids in the bulk solution and neglect the reactions that occur at the interface. In this study, using the field-induced droplet ionization mass spectrometry methodology that is capable of selectively sampling amphiphilic molecules that reside at the air-water interface, we show that the acid-mediated photochemistry of 2-oxooctanoic acid and 2-oxoheptoic acid is highly different from those of previously reported reactions in the bulk and contributes to the formation of humic-like substances (HULIS). This work emphasizes the uniqueness of the photochemistry at the air-water interface. We anticipate that studies of atmosphere-relevant photochemistry at the air-water interface will be an avenue rich with opportunities.
由于其在大气和前生物化学中的意义，α-酮酸的光化学一直受到极大关注。具有长烷基链的α-酮酸本质上是两亲性的，它们往往在大气水滴的气-水界面处分配，并增加了其中化学物质的复杂性。气-水界面是一个独特的环境，对整个大气过程起着至关重要的作用。然而，现有的研究大多集中在α-酮酸在本体溶液中的光化学反应，而忽略了在界面处发生的反应。在这项研究中，我们使用场致离子化质谱方法选择性地采样气-水界面上的两亲性分子，结果表明，酸介导的 2-氧代辛酸和 2-氧代庚酸的光化学反应与以前在本体中报道的反应有很大的不同，并有助于腐殖质样物质（HULIS）的形成。这项工作强调了气-水界面光化学的独特性。我们预计，在气-水界面进行与大气相关的光化学研究将是一个充满机遇的领域。
