Minimizing Errors in Measured Yields of Particle-Phase Products Formed in Environmental Chamber Reactions: Revisiting the Yields of β-Hydroxynitrates Formed from 1-Alkene + OH/NO x Reactions
Minimizing Errors in Measured Yields of Particle-Phase Products Formed in Environmental Chamber Reactions: Revisiting the Yields of β-Hydroxynitrates Formed from 1-Alkene + OH/NO x Reactions
复制标题
最小化环境室反应中形成的颗粒相产物的测量产率误差：重新审视 1-烯烃 OH/NO x 反应形成的 β-羟基硝酸盐的产率
DOI：
10.1021/acsearthspacechem.1c00008
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发表时间：
2021
影响因子：
3.4
通讯作者：
Ziemann, Paul J.
中科院分区：
文献类型：
--
作者：
Bakker-Arkema, Julia G.;Ziemann, Paul J.
环境室研究广泛用于测量挥发性有机化合物氧化形成的反应产物和二次有机气溶胶的产率，这些信息随后可用于开发化学反应机制和大气化学模型。然而，这种测量是具有挑战性的，并且许多潜在的误差来源并不总是被认识到。在这里，我们描述的方法，最大限度地减少和占的不确定性与腔室的体积，气体和颗粒采样，仪器校准，气体壁分区，颗粒沉积到墙壁，和二次反应与OH自由基和证明这些方法通过测量产率和分支比形成的β-羟基硝酸酯从反应的C14和C151-烯烃与OH自由基在NOx的存在下。实验在Teflon环境室中进行，包括烯烃的Tenax采样，通过气相色谱法与火焰离子化检测器进行分析，颗粒相β-羟基硝酸酯和邻苯二甲酸二辛酯种子颗粒的过滤器采样，通过液相色谱法与UV/维斯检测器进行分析，以及使用扫描迁移率粒度仪和热解吸粒子束质谱仪测量气溶胶体积浓度和组成。测得的β-羟基硝酸酯的产率比以前使用类似方法测定的产率高出约25%，这些方法的不确定性没有得到很好的最小化和表征。
Environmental chamber studies are widely used for measuring the yields of reaction products and secondary organic aerosol formed from the oxidation of volatile organic compounds, information that can be subsequently used to develop chemical reaction mechanisms and models of atmospheric chemistry. Such measurements are challenging, however, and many potential sources of errors are not always appreciated. Here, we describe methods for minimizing and accounting for uncertainties associated with the chamber volume, gas and particle sampling, instrument calibrations, gas–wall partitioning, particle deposition to walls, and secondary reactions with OH radicals and demonstrate these methods by measuring yields and branching ratios for the formation of β-hydroxynitrates from reactions of C14and C151-alkenes with OH radicals in the presence of NOx. Experiments were conducted in a Teflon environmental chamber and included Tenax sampling of alkenes with analysis by gas chromatography with flame ionization detection, filter sampling of particle-phase β-hydroxynitrates and dioctyl phthalate seed particles with analysis by liquid chromatography with UV/vis detection, and measurements of aerosol volume concentration and composition using a scanning mobility particle sizer and thermal desorption particle beam mass spectrometer. The measured yields of β-hydroxynitrates are ∼25% higher than those determined previously using similar methods whose uncertainties were less well minimized and characterized.