Negative ions generated by reactions with oxygen in the chemical ionization source. I. Characterization of gas-phase and wall-catalyzed reactions of fluorene, anthracene and fluoranthene

1989 ◽  
Vol 24 (2) ◽  
pp. 94-104 ◽  
Author(s):  
Elizabeth A. Stemmler ◽  
Michelle V. Buchanan
Keyword(s):  
Gas Phase ◽  
Chemical Ionization ◽  
Negative Ions ◽  
Ionization Source ◽  
Chemical Ionization Source ◽  
Catalyzed Reactions

Atmospheric Pressure Chemical Ionization Source. 1. Ionization of Compounds in the Gas Phase

2008 ◽  
Vol 80 (8) ◽  
pp. 2646-2653 ◽  
Author(s):  
Francisco J. Andrade ◽  
Jacob T. Shelley ◽  
William C. Wetzel ◽  
Michael R. Webb ◽  
Gerardo Gamez ◽  
...  
Keyword(s):  
Gas Phase ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Atmospheric Pressure Chemical Ionization ◽  
Ionization Source ◽  
Chemical Ionization Source ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical

Ion chemistry of second-row transition metals in hydrocarbon flames: cations and anions of Y, Zr, Nb, and Mo

1995 ◽  
Vol 73 (12) ◽  
pp. 2263-2271 ◽  
Author(s):  
Christine C.Y. Chow ◽  
John M. Goodings
Keyword(s):  
Transition Metals ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Negative Ions ◽  
Ion Concentration ◽  
Oxidation States ◽  
Metallic Ions ◽  
Ion Chemistry ◽  
Hydrocarbon Flames

A pair of laminar, premixed, CH4–O2 flames above 2000 K at atmospheric pressure, one fuel-rich (FR) and the other fuel-lean (FL), were doped with ~10−6 mol fraction of the second-row transition metals Y, Zr, Nb, and Mo. Since these hydrocarbon flames contain natural ionization, metallic ions were produced in the flames by the chemical ionization (CI) of metallic neutral species, primarily by H3O+ and OH− as CI sources. Both positive and negative ions of the metals were observed as profiles of ion concentration versus distance along the flame axis by sampling the flames through a nozzle into a mass spectrometer. For yttrium, the observed ions include the YO+•nH2O (n = 0–3) series, and Y(OH)4−. With zirconium, they include the ZrO(OH)+•nH2O (n = 0–2) series, and ZrO(OH)3−. Those observed with niobium were the cations Nb(OH)3+ and Nb(OH)4+, and the single anion NbO2(OH)2−. For molybdenum, they include the cations MoO(OH)2+ and MoO(OH)3+, and the anions MoO3− and MoO3(OH)−. Not every ion was observed in each flame; the FL flame tended to favour the ions in higher oxidation states. Also, flame ions in higher oxidation states were emphasized for these second-row transition metals compared with their first-row counterparts. Some ions written as members of hydrate series may have structures different from those of simple hydrates; e.g., YO+•H2O = Y(OH)2+ and ZrO(OH)+•H2O = Zr(OH)3+, etc. The ion chemistry for the production of these ions by CI in flames is discussed in detail. Keywords: transition metals, ions, flame, gas phase, negative ions.

Negative Ion Mass Spectra of Organic Nitriles

1981 ◽  
Vol 35 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Kenneth L. Bush ◽  
Carol E. Parker ◽  
Donald J. Harvan ◽  
Maurice M. Bursey ◽  
J. Ronald Hass
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Detection Limits ◽  
Negative Ion ◽  
Ionization Source ◽  
Ion Molecule Reactions ◽  
Residual Oxygen ◽  
Chemical Ionization Source ◽  
Positive Ion

Negative ion mass spectra organic nitriles have been determined using 1 Torr of methane moderator/reagent gas in a chemical ionization source. The spectra contain abundant (M – 1)− ions, and fragmentations are minimal. Ion/molecule reactions with residual oxygen, methane, and between sample molecules and ions form diverse products with low abundances relative to the ( M – 1)−. Detection limits are comparable with positive ion methods, and for selected compounds, can be several orders of magnitude lower.

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