Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
Environ Sci Technol. 2014 Apr 15;48(8):4266-72. doi: 10.1021/es401770y. Epub 2014 Mar 31.
Hydroxyl radicals were generated from an aqueous suspension of ambient PM2.5 and detected utilizing 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap coupled with electron paramagnetic resonance (EPR) spectroscopy. Results from this study suggested the importance of environmentally persistent free radicals (EPFRs) in PM2.5 to generate significant levels of ·OH without the addition of H2O2. Particles for which the EPFRs were allowed to decay over time induced less hydroxyl radical. Additionally, higher particle concentrations produced more hydroxyl radical. Some samples did not alter hydroxyl radical generation when the solution was purged by air. This is ascribed to internal, rather than external surface associated EPFRs.
羟基自由基是由环境 PM2.5 的水悬浮液产生的,并利用 5,5-二甲基-1-吡咯啉-N-氧化物(DMPO)作为自旋捕获剂,结合电子顺磁共振(EPR)光谱进行检测。本研究的结果表明,环境持久性自由基(EPFRs)在 PM2.5 中生成大量·OH 的重要性,而无需添加 H2O2。随着时间的推移,EPFR 衰减的颗粒会导致羟基自由基生成减少。此外,更高的颗粒浓度会产生更多的羟基自由基。当溶液通过空气吹扫时,一些样品不会改变羟基自由基的生成,这归因于内部而非外部表面相关的 EPFRs。