Lloyd Julie A, Heaton Katherine J, Johnston Murray V
J Phys Chem A. 2009 Apr 30;113(17):4840-3. doi: 10.1021/jp900634d.
The reaction of trimethylamine (TMA) vapor with a polydisperse distribution of ammonium nitrate particles (20-500 nm dia.) was studied in a flow tube reactor with particle analysis by laser desorption (1064 nm) 70 eV electron ionization (EI) in an ion trap time-of-flight (IT-TOF) aerosol mass spectrometer. When the TMA vapor concentration was very high, essentially complete exchange of TMA for ammonia in the particles was achieved. When the TMA vapor concentration was lower ( approximately 500 ppb for a reaction time of 23 s), partial exchange was observed, and the initial reactive uptake coefficient was estimated to be on the order of 2 x 10(-3) at 20% RH. This value suggests that measurable exchange is possible in the atmosphere when particles are exposed to an amine concentration on the order of 1 ppb for a few hours. The effects of particle size, water content, and amine molecular structure on uptake remain to be elucidated.
在流动管反应器中，利用离子阱飞行时间（IT-TOF）气溶胶质谱仪，通过激光解吸（1064 nm）和70 eV电子电离（EI）对颗粒进行分析，研究了三甲胺（TMA）蒸汽与多分散分布的硝酸铵颗粒（直径20 - 500 nm）之间的反应。当TMA蒸汽浓度非常高时，颗粒中的TMA与氨基本实现了完全交换。当TMA蒸汽浓度较低时（反应时间23 s时约为500 ppb），观察到了部分交换，在20%相对湿度下，初始反应吸收系数估计约为2×10⁻³。该值表明，当颗粒在数小时内暴露于约1 ppb的胺浓度下时，大气中可能发生可测量的交换。颗粒大小、含水量和胺分子结构对吸收的影响仍有待阐明。
