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.

Ion chemistry of transition metals in hydrocarbon flames. II. Cations of Sc, Ti, V, Cr, and Mn

1988 ◽  
Vol 66 (9) ◽  
pp. 2219-2228 ◽  
Author(s):  
John M. Goodings ◽  
Quang Tran ◽  
Nicholas S. Karellas
Keyword(s):  
Transition Metals ◽  
Metal Atom ◽  
Chemical Ionization ◽  
Metallic Ions ◽  
Ion Chemistry ◽  
Hydrocarbon Flames ◽  
Basic Series ◽  
First Time ◽  
Isomeric Structures

The same fuel-rich, premixed, conical, methane–oxygen flame at 2200 K and atmospheric pressure used for studies of Fe, Co, Ni, Cu, and Zn in Part I (1) is doped with the same concentration (~1 ppm) of Sc, Ti, V, Cr, and Mn to complete the first row of ten transition metals. Metallic ions of these metals and their compounds formed by chemical ionization reactions with H3O+ are observed by sampling the flame through a nozzle into a quadrupole mass spectrometer. Concentration profiles of individual and total cations are measured as a function of distance along the flame axis, and also mass spectra at a fixed point in the burnt gas. If A is the metal atom, the observed ions can be represented by four hydrate series including (a) A+•nH2O, (b) AOH+•nH2O, (c) AO+•nH2O, and (d) AO2H+•nH2O with n = 0–3 or 4, giving a maximum of four ligands around the metal atom. However, alternative isomeric structures are possible for each of the four basic series (e.g. AO+•2H2O ~ A(OH)2+•H2O ~ A(OH)3H+). The ions observed with Cr and Mn, in common with those of Fe, Co, Ni, and Cu, strongly favour series (a). On the other hand, Sc is completely different; the ions of series (c) are dominant. All four series are observed with each of Ti and V. Series (b) dominates for Ti and series (c) for V; ions from series (d) were observed for the first time. The ion chemistry of these metals is discussed in detail with emphasis on the probable chemical ionization reactions responsible for metallic ion formation. The pre-eminent role of proton transfer processes is apparent.

Development and use of analytical systems based on mass spectrometry.

1977 ◽  
Vol 23 (1) ◽  
pp. 13-21 ◽  
Author(s):  
E C Horning ◽  
D I Carroll ◽  
I Dzidic ◽  
K D Haegele ◽  
S Lin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Negative Ions ◽  
Atmospheric Pressure Ionization ◽  
Gas Chromatograph ◽  
Ion Molecule Reactions ◽  
Ionization Mode ◽  
Effluent Stream

Abstract Contemporary analytical systems based on mass spectrometry include as components a gas chromatograph, a mass spectrometer, and a computer. The form of operation is usually in electron impact ionization mode for identification and structural studies, and in chemical ionization mode for quantitative analyses. Important stages in the development of these systems included the design of "molecule separators" for the concentration of solutes in the gas phase, the use of mass spectrometers as specific ion detectors, the introduction of chemical ionization techniques, and the development of computer-based operation, data acquisition, and data analysis capabilities. A current line of investigation is concerned with the design and use of systems based on atmospheric pressure ionization. Samples are ionized in a small reaction chamber external to the low-pressure region of a quadrupole mass analyzer. The primary source of electrons is a 63Ni foil or a corona discharge. The ionization process leading to positive ions involves a sequence of ion molecule reactions, usually electrons leads to carrier gas ions leads to reagent ions leads to sample component ions. Negative ions may be formed by direct electron attachment, or by ion molecule reactions that include new types of elimination reactions. The source will accept a variety of gases and solvents. The sample may be introduced in the gas phase without solvents, by probe injection, or in the effluent stream from a gas chromatograph. Samples may be introduced in the liquid phase in solvents by injection after the fashion of gas chromatography or in the effluent stream from a high-performance liquid chromatograph. The novel aspects of atmospheric pressure ionization mass spectrometry lie in its versatility and high sensitivity of detection. Few clinical chemistry laboratories now use these systems. Significant future uses are likely to be in analytical work involving therapeutic drug monitoring and studies of drug metabolism, and in analyses for environmental biohazards including pesticides, herbicides, polyhalobiphenyls, dibenzodioxins, and other toxic compounds.

Sulphurous negative ions in a fuel-rich, CH4–O2 flame with OCS additive

1983 ◽  
Vol 61 (8) ◽  
pp. 1703-1711 ◽  
Author(s):  
John M. Goodings ◽  
Kamal Elguindi ◽  
Diethard K. Bohme
Keyword(s):  
Reaction Zone ◽  
Atmospheric Pressure ◽  
Negative Ions ◽  
Ion Concentration ◽  
Quadrupole Mass ◽  
Ion Chemistry ◽  
Naturally Occurring ◽  
Pressure Profiles ◽  
Ion Profiles ◽  
Carbonyl Sulphide

Sulphurous negative ions S • SH • SO • SO2/S2• SO3• HSO3• SO4• and HSO4 were observed when 0.2% of carbonyl sulphide (OCS) was added to a conical, laminar, premixed. fuel-rich (equivalence ratio [Formula: see text]) CH4–O2 flame burning at atmospheric pressure. Profiles were obtained of ion concentration vs. distance along the flame axis by sampling the flame through a pinhole into a quadrupole mass spectrometer. Some of the ion signals observed in the flame reaction zone are very large, particularly that for HSO4. None of the sulphurous ions detected contain carbon. Of those listed above, only S−,•SH, • SO • and SO2 persist downstream through the burnt gas. The sulphurous ions are formed by chemical ionization processes of neutral sulphurous intermediates reacting with the naturally-occurring ions present in any hydrocarbon flame. The ion chemistry is discussed, as is the underlying neutral chemistry of sulphur relevant to the flame environment. The ion profiles show the rapidity with which OCS is oxidized through SH and SO to SO2 even within the reaction zone of this fuel-rich flame. No evidence was obtained for the presence of sulphuric or sulphurous acids, and the presence of S2: was not confirmed.

Sulphur anion chemistry in hydrocarbon flames with H2S, OCS, and SO2 additives

1986 ◽  
Vol 64 (4) ◽  
pp. 689-694 ◽  
Author(s):  
John M. Goodings ◽  
Diethard K. Bohme ◽  
Kamal Elguindi ◽  
Arnold Fox
Keyword(s):  
Rate Constants ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Negative Ions ◽  
Ion Concentration ◽  
Concentration Profiles ◽  
Hydrocarbon Flame ◽  
Flowing Afterglow ◽  
Hydrocarbon Flames ◽  
Oxygen Flame

A premixed, fuel-rich, methane–oxygen flame at atmospheric pressure was doped separately with 0.2 mol% of H2S, OCS, and SO2 to probe the behaviour of fuel sulphur during combustion. These three additives represent compounds occurring early, intermediate, and late in the oxidation sequence of fuel sulphur. They are chemically ionized in the reaction zone of a hydrocarbon flame to give large signals of sulphurous negative ions. Those detected include S−, SH−, SO− (uncertain), SO2− (S2−), SO3−, HSO3−, CH3O−•SO2, SO4− (S2O2−, S3−), and HSO4−. Ion concentration profiles of these ions were measured along the conical flame axis by sampling the flame into a mass spectrometer. The shapes of the profiles are insensitive to the nature of the additive, but their relative magnitudes are indicative of the additive's position in the sulphur oxidation sequence. For each additive, the very large HSO4− signal has analytical implications as an indicator for total fuel sulphur. The sulphurous anion chemistry is discussed for each additive in terms of roughly twenty ion (electron)-molecule reactions of six basic types, whose rate constants were known previously, or were measured at room temperature using the York flowing afterglow apparatus.

Ion chemistry of aluminum and boron in methane–oxygen flames

1992 ◽  
Vol 70 (3) ◽  
pp. 839-848 ◽  
Author(s):  
Pierre N. Crovisier ◽  
J. Hugh Horton ◽  
Carl S. Hassanali ◽  
John M. Goodings
Keyword(s):  
Transition Metals ◽  
Proton Transfer ◽  
Gas Phase ◽  
Oxidation State ◽  
Mass Spectrometer ◽  
Atmospheric Pressure ◽  
Concentration Level ◽  
Ion Chemistry ◽  
Low Concentration ◽  
Boron Ions

The ion chemistry of aluminum and boron, primarily in the +3 oxidation state, was studied by doping premixed, methane–oxygen flames of both fuel-rich and fuel-lean (oxygen-rich) composition with 1 × 10−6 mol fraction of AlCl3 and 5 × 10−4 mol fraction of B(OC2H5)3. Ions were observed by sampling the flames at atmospheric pressure through a nozzle into a mass spectrometer. At this low concentration level, aluminum exhibits two cation series: (a) AlO+•nH2O (n = 2, 3) formed by proton transfer to AlO(OH) and Al(OH)3 in which hydration reactions are involved; and (b) Al+•nH2O (n = 0, 1) by protonation of AlOH with hydration/dehydration steps. At the higher concentration of the boron additive, four cation series were observed: (a) B(OC2H5)3H+•nH2O (n = 0, 1) based on proton transfer to the B(OC2H5)3 additive; (b) BO+•nH2O (n = 1–4) similar to aluminum; (c) HB2O3+•nH2O (n = 1–3) involving the protonated dimer of metaboric acid, BO(OH); and (d) B3O4+•nH2O (n = 2, 3) involving the protonated trimer of BO(OH) whose structures might be cyclic or linear. Other series members are formed by subsequent hydration or dehydration of the parent cations. The anions BO2− and BO− previously studied by D. E. Jensen were also observed. The formation chemistry and probable structures of these ions are discussed, and compared with similar results obtained previously for flames doped with transition metals; notably Sc, Ti, V, and Cr in the +3 oxidation state. Keywords: aluminum, boron, ions, flame, gas phase.

Newly developed instrumentation for measuring highly oxidized molecules at atmospheric pressure

2021 ◽  
Author(s):  
Paap Koemets ◽  
Sander Mirme ◽  
Kuno Kooser ◽  
Heikki Junninen
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Measurement Technology ◽  
Differential Mobility Analyzer ◽  
Neutral Cluster ◽  
Differential Mobility ◽  
Alpha Pinene ◽  
Ambient Measurements

<p>The Highly Oxidized Molecule Ion Spectrometer (HOMIS) is a novel instrument for measuring the total concentration of highly oxidized molecules (HOM-s) (Bianchi et al., 2019) at atmospheric pressure. The device combines a chemical ionization charger with a multi-channel differential mobility analyzer. The chemical ionization charger is based on the principles outlined by Eisele and Tanner (1993). The charger is attached to a parallel differential mobility analyzer identical to the ones used in the Neutral cluster and Air Ion Spectrometer (NAIS, Mirme 2011), but with modified sample and sheath air flow rates to improve the mobility resolution of the device. The complete mobility distribution in the range from 3.2 to 0.056 cm<sup>2</sup>/V/s is measured simultaneously by 25 electrometers. The range captures the charger ions, monomers, dimers, trimers but also extends far towards larger particles to possibly detect larger HOM-s that have not been measured with existing instrumentation. The maximum time resolution of the device is 1 second allowing it to detect rapid changes in the sample. The device has been designed to be easy to use, require little maintenance and work reliably in various environments during long term measurements.</p><p>First results of the prototype were acquired from laboratory experiments and ambient measurements. Experiments were conducted at the Laboratory of Environmental Physics, University of Tartu. The sample was drawn from a reaction chamber where alpha-pinene and ozone were introduced. Initial results show a good response when concentrations of alpha-pinene and ozone were changed. </p><p>Ambient measurements were conducted at the SMEAR Estonia measurement station in a hemiboreal forest for 10 days in the spring and two months in the winter of 2020. The HOMIS measurements were performed together with a CI-APi-TOF (Jokinen et al., 2012).</p><p> </p><p>References:</p><p>Bianchi, F., Kurtén, T., Riva, M., Mohr, C., Rissanen, M. P., Roldin, P., Berndt, T., Crounse, J. D., Wennberg, P. O., Mentel, T. F., Wildt, J., Junninen, H., Jokinen, T., Kulmala, M., Worsnop, D. R., Thornton, J. A., Donahue, N., Kjaergaard, H. G. and Ehn, M. (2019), “Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol”, Chemical Reviews, 119, 6, 3472–3509</p><p>Eisele, F. L., Tanner D. J. (1993), “Measurement of the gas phase concentration of H2SO4 and methane sulfonic acid and estimates of H2SO4 production and loss in the atmosphere”, JGR: Atmospheres, 98, 9001-9010</p><p>Jokinen T., Sipilä M., Junninen H., Ehn M., Lönn G., Hakala J., Petäjä T., Mauldin III R. L., Kulmala M., and Worsnop D. R. (2012), “Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF”, Atmospheric Chemistry and Physics, 12, 4117–4125</p><p>Mirme, S. (2011), “Development of nanometer aerosol measurement technology”, Doctoral thesis, University of Tartu</p>

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

Silicon cation and anion chemistry in a fuel-rich, methane–oxygen flame

1992 ◽  
Vol 70 (4) ◽  
pp. 1069-1081 ◽  
Author(s):  
J. Hugh Horton ◽  
John M. Goodings
Keyword(s):  
Nucleophilic Substitution ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Orthosilicic Acid ◽  
Ion Chemistry ◽  
Silicon Ions ◽  
Normal Carbon ◽  
Silicon Chemistry ◽  
Three Body ◽  
Oxygen Flame

Silicon cations and anions in a fuel-rich, premixed, methane–oxygen flame at atmospheric pressure doped with 0.01 mol% of trimethylsilane were observed by sampling the flame through a nozzle into a mass spectrometer. Twelve cations were observed which can be grouped into five series: SiOH+.nH2O (n = 0–2); SiOCH3+.nH2O (n = 0–2); Si(OH)3+.nH2O (n = 0–2); cations by nucleophilic substitution (e.g., Si(OH)(CH3)2(H2O)+); and carbonaceous aromatic cations (c-HSiCH=CH+ and c-HSiCH=CCH3+). Similarly, five anions were observed as members of two series: HxSiO3− (x = 0, 1) and HxSiO4− (x = 1–3). The chemical ionization reactions for the formation of these ions are discussed in detail, including proton transfer and also methyl cation transfer, three-body addition, nucleophilic substitution (SN2) of both the ions themselves and also their neutral silicon precursors, and H-atom abstraction reactions. The neutral silicon chemistry in the flame is dominated by SiO, but evidence was obtained from both the cation and the anion chemistry for the presence of HSiO(OH), silanoic acid; SiO(OH)2, metasilicic acid; and Si(OH)4, orthosilicic acid. The silicon ion chemistry differs markedly from the normal carbon ion chemistry that occurs naturally in the undoped methane–oxygen flame; the silicon ions show a strong tendency towards Si—O bond formation. Consideration is given to the probable structures of the various silicon cations and anions observed.

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