Capture of Hydroxyl Radicals by Hydronium Cations in Water Microdroplets
Abstract
Despite the high stability of bulk water, water microdroplets possess strikingly different properties, such as the presence of hydroxyl radicals (OH⋅) at the air–water interface. Previous studies exhibited the recombination of OH⋅ into H2O2 molecules and the capture of OH⋅ by oxidizing other molecules. By spraying pure water microdroplets into a mass spectrometer, we detected OH⋅ in the form of (H4O2)+ that is essentially OH⋅−H3O+, a hydroxyl radical combined with a hydronium cation through hydrogen bonding. We also successfully captured it with two OH⋅ scavengers, caffeine and melatonin, and key oxidation radical intermediates that bear important mechanistic information were seen. It is suggested that some previous reactions involving (H4O2)+ should be attributed to reactions with OH⋅−H3O+ rather than with the water dimer cation (H2O−OH2)+.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 08, 2022
- Source ID
- 10.1002/ange.202207587
Entities
People
- Dong Xing
- Richard Zare
- Shuihui Jin
- Xiaowei Song
- Xinxing Zhang
- Xu Yuan
- Yifan Meng
Organizations
- Air Force Office of Scientific Research
- Beijing National Laboratory for Molecular Sciences
- National Natural Science Foundation of China
- Natural Science Foundation of Tianjin City
- Stanford University