DOI: 10.1016/j.atmosenv.2014.09.014
Scopus记录号: 2-s2.0-84908029623
论文题名: Comparison of negative-ion proton-transfer with iodide ion chemical ionization mass spectrometry for quantification of isocyanic acid in ambient air
作者: Woodward-Massey R ; , Taha Y ; M ; , Moussa S ; G ; , Osthoff H ; D
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2014
卷: 98 起始页码: 693
结束页码: 703
语种: 英语
英文关键词: Chemical ionization mass spectrometry
; Iodide reagent ion
; Isocyanic acid
; Negative-ion proton-transfer
; Urban pollution
Scopus关键词: Ambient air
; Chemical ionization mass spectrometry
; Iodide ion
; Isocyanic acids
; Negative-ion proton-transfer
; Urban pollutions
; gasoline
; iodide ion
; isocyanate
; nitrogen oxide
; ambient air
; concentration (composition)
; humidity
; iodide
; ion exchange
; ionization
; laboratory method
; mass spectrometry
; nitric oxide
; urban pollution
; air sampling
; ambient air
; Article
; Canada
; comparative study
; humidity
; mass spectrometry
; motor vehicle
; proton transport
; sensitivity analysis
; signal noise ratio
; water vapor
; Alberta
; Calgary
; Canada
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: Isocyanic acid (HNCO) is a trace gas pollutant of potential importance to human health whose measurement has recently become possible through the development of negative-ion proton-transfer chemical ionization mass spectrometry (NI-PT-CIMS) with acetate reagent ion. In this manuscript, an alternative ionization and detection scheme, in which HNCO is quantified by iodide CIMS (iCIMS) as a cluster ion at m/z 170, is described. The sensitivity was inversely proportional to water vapor concentration but could be made independent of humidity changes in the sampled air by humidifying the ion-molecule reaction (IMR) region of the CIMS. The performance of the two ionization schemes was compared and contrasted using ambient air measurements of HNCO mixing ratios in Calgary, AB, Canada, by NI-PT-CIMS with acetate reagent ion from Dec 16 to 20, 2013, and by the same CIMS operated in iCIMS mode from Feb 3 to 7, 2014. The iCIMS exhibited a greater signal-to-noise ratio than the NI-PT-CIMS, not because of its sensitivity, which was lower (~0.083 normalized counts per second (NCPS) per parts-per-trillion by volume (pptv) compared to ~9.7NCPSpptv -1), but because of a much lower and more stable background (3±4 compared to a range of ~2×103 to ~6×103NCPS). For the Feb 2014 data set, the HNCO mixing ratios in Calgary air ranged from <12 to 94pptv (median 34pptv), were marginally higher at night than during day, and correlated with nitrogen oxide (NOx=NO+NO2) mixing ratios and submicron particle volume. The ratios of HNCO to NOx observed are within the range of emission ratios reported for gasoline-powered motor vehicles. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/80502
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Chemistry, University of Calgary, Calgary, AB, Canada; Department of Chemistry, Durham University, Durham, United Kingdom; Air Quality Research Division, Environment Canada, 4905 Dufferin Street, Toronto, ON, Canada
Recommended Citation:
Woodward-Massey R,, Taha Y,M,et al. Comparison of negative-ion proton-transfer with iodide ion chemical ionization mass spectrometry for quantification of isocyanic acid in ambient air[J]. Atmospheric Environment,2014-01-01,98