title: [Development of a chemical ionization time-of-flight mass spectrometer for continuous measurements of atmospheric hydroxyl radical].
abstract: A home-made chemical ionization time-of-flight mass spectrometer (TOFMS) has been developed for continuous measurements of atmospheric hydroxyl radical. Based on the atmospheric pressure chemical ionization technique, an ionization source with orthogonal dual tube structure was adopted in the instrument, which minimized the interference between the reagent gas ionization and the titration reaction. A 63Ni radioactive source was fixed inside one of the orthogonal tubes to generate reactant ion of NO(-)(3) from HNO3 vapor. Hydroxyl radical was first titrated by excess SO2 to form equivalent concentrations of H2SO4 in the other orthogonal tube, and then reacted with NO(-)(3) ions in the chemical ionization chamber, leading to HSO(-)(4) formation. The concentration of atmospheric hydroxyl radical can be directly calculated by measuring the intensities of the HSOj product ions and the NO(-)(3) reactant ions. The analytical capability of the instrument was demonstrated by measuring hydroxyl radical in laboratory air, and the concentration of the hydroxyl radical in the investigated air was calculated to be 1.6 x 106 molecules*cm ', based on 5 seconds integration. The results have shown that the instrument is competent for in situ continuous measurements of atmospheric trace radical.
authors: Jian
authors: J
authors: Dou
authors: Lei
authors: L
authors: Hua
authors: Ke-Yong
authors: KY
authors: Hou
authors: Lei
authors: L
authors: Jiang
authors: Yuan-Yuan
authors: YY
authors: Xie
authors: Wu-Duo
authors: WD
authors: Zhao
authors: Ping
authors: P
authors: Chen
authors: Wei-Guo
authors: WG
authors: Wang
authors: Tian
authors: T
authors: Di
authors: Hai-Yang
authors: HY
authors: Li
mesh_terms: D001272:Atmosphere / Q000032:analysis*; D005740:Gases; D017665:Hydroxyl Radical / Q000032:analysis*; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D005740:Gases; D007477:Ions; D017665:Hydroxyl Radical