1
|
Mahata S, Bhattacharya SK, Liang MC. An improved method of high-precision determination of Δ(17)O of CO2 by catalyzed exchange with O2 using hot platinum. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:119-131. [PMID: 26661978 DOI: 10.1002/rcm.7423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/07/2015] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE CO2 and O2 can exchange their oxygen isotopes rapidly in the presence of hot (~670 °C) platinum and this has led to a method for determining the δ(17)O value of a CO2 sample. We have improved the method to achieve a precision of 0.008 ‰ (1-σ standard deviation) in the determination of δ(17)O values. Such high precision is essential to identify the stratospheric component in tropospheric CO2 and use it for global carbon flux studies. The crucial issue in the accurate determination of the δ(17)O value is estimation of a correction factor, which depends on the amount ratio CO2/O2. An attempt was also made to investigate the mechanism of exchange with their controlling parameters. METHODS The oxygen isotopes of a CO2 sample gas are exchanged with those of an appropriate amount of tank O2 in the presence of hot platinum. The pre-exchange CO2 and O2 gas samples as well as the post-exchange O2 sample are analyzed by isotope ratio mass spectrometry. A mixing model was developed involving the δ(18)O value of the CO2 and δ(17)O and δ(18)O values of pre- and post-exchange O2 to obtain the δ(17)O value of the CO2 sample. A correction to the measured value was determined to obtain the actual value with high accuracy and precision. RESULTS To obtain a precision better than 0.01 ‰ requires the amount ratio CO2/O2 to be controlled to better than ~15 %. We also find that the oxygen isotopes are nearly homogeneously distributed between the O2 and the CO2 molecules. In addition, determination of the (16) O(13)C(18)O/(16)O(12)C(16)O isotopologue ratio in the CO2 shows that the abundance of (16)O(13)C(18)O is close to that expected for random partitioning of the isotopes among the CO2 isotopologues. CONCLUSIONS The isotopic scrambling between O2 and CO2 that occurs on hot platinum allows one to accurately determine the δ(17)O values of CO2 through isotopic analysis of O2.
Collapse
Affiliation(s)
- Sasadhar Mahata
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - S K Bhattacharya
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - Mao-Chang Liang
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Astronomy, National Central University, Jhongli, Taiwan
- Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
- Department of Physics, University of Houston, Houston, TX, USA
| |
Collapse
|
2
|
Mukotaka A, Toyoda S, Yoshida N, Well R. On-line triple oxygen isotope analysis of nitrous oxide using decomposition by microwave discharge. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2391-2398. [PMID: 24097395 DOI: 10.1002/rcm.6698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/12/2013] [Accepted: 07/26/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE The oxygen isotope anomaly, Δ(17)O, of N2O and nitrate is useful to elucidate nitrogen oxide dynamics. The previously developed method for Δ(17)O measurement presents difficulty in maintaining optimal conditions of the gold tube for thermal decomposition of N2O to O2 and the Δ(17)O value is also sample size dependent. METHODS Trace amounts (5-40 nmol) of N2O were decomposed quantitatively to O2 in a quartz tube by microwave discharge. The O2 was purified using gas chromatography. Triple oxygen isotopes were measured using isotope ratio mass spectrometry. Each step was connected online and was applied to the analysis of nitrate in precipitation samples collected in Yokohama, Japan. RESULTS Precision (1σ) of Δ(17)O analysis was better than 0.26‰ when more than 20 nmol of N2O with a small Δ(17)O value (approx. 1‰) was measured. It was better than 0.76‰ when more than 60 nmol of nitrate was converted into N2O using the denitrifier method and then measured on the developed system. The obtained Δ(17)O values in precipitation samples (14.5-26.4‰) agreed with findings from previous studies. CONCLUSIONS A novel on-line analytical method was developed to measure the triple oxygen isotopes of N2O using microwave discharge to decompose N2O. This easy-to-use method is free from conditioning of reaction devices, and is applicable to molecules other than N2O such as NO and NO2.
Collapse
Affiliation(s)
- Arata Mukotaka
- Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | | | | | | |
Collapse
|
3
|
Sulfur isotopic fractionation in vacuum UV photodissociation of hydrogen sulfide and its potential relevance to meteorite analysis. Proc Natl Acad Sci U S A 2013; 110:17650-5. [PMID: 23431159 DOI: 10.1073/pnas.1213150110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Select meteoritic classes possess mass-independent sulfur isotopic compositions in sulfide and organic phases. Photochemistry in the solar nebula has been attributed as a source of these anomalies. Hydrogen sulfide (H2S) is the most abundant gas-phase species in the solar nebula, and hence, photodissociation of H2S by solar vacuum UV (VUV) photons (especially by Lyman-α radiation) is a relevant process. Because of experimental difficulties associated with accessing VUV radiation, there is a paucity of data and a lack of theoretical basis to test the hypothesis of a photochemical origin of mass-independent sulfur. Here, we present multiisotopic measurements of elemental sulfur produced during the VUV photolysis of H2S. Mass-independent sulfur isotopic compositions are observed. The observed isotopic fractionation patterns are wavelength-dependent. VUV photodissociation of H2S takes place through several predissociative channels, and the measured mass-independent fractionation is most likely a manifestation of these processes. Meteorite sulfur data are discussed in light of the present experiments, and suggestions are made to guide future experiments and models.
Collapse
|
4
|
The Isotopomers of Nitrous Oxide: Analytical Considerations and Application to Resolution of Microbial Production Pathways. ADVANCES IN ISOTOPE GEOCHEMISTRY 2012. [DOI: 10.1007/978-3-642-10637-8_23] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
|
5
|
Daud MN. UV Photolysis of N2O Isotopomers: Isotopic Fractionations and Product Rotational Quantum State Distributions. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/06/679-685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
6
|
Laube JC, Kaiser J, Sturges WT, Bönisch H, Engel A. Chlorine Isotope Fractionation in the Stratosphere. Science 2010; 329:1167. [DOI: 10.1126/science.1191809] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- J. C. Laube
- School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK
| | - J. Kaiser
- School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK
| | - W. T. Sturges
- School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK
| | - H. Bönisch
- Institute for Atmosphere and Environment, University of Frankfurt, 60438 Frankfurt (Main), Germany
| | - A. Engel
- Institute for Atmosphere and Environment, University of Frankfurt, 60438 Frankfurt (Main), Germany
| |
Collapse
|
7
|
Prasad SS, Zipf EC. Atmospheric production of nitrous oxide from excited ozone and its potentially important implications for global change studies. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009447] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
8
|
Komatsu DD, Ishimura T, Nakagawa F, Tsunogai U. Determination of the 15N/14N, 17O/16O, and 18O/16O ratios of nitrous oxide by using continuous-flow isotope-ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:1587-1596. [PMID: 18433083 DOI: 10.1002/rcm.3493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We developed a rapid, sensitive, and automated analytical system to determine the delta15N, delta18O, and Delta17O values of nitrous oxide (N2O) simultaneously in nanomolar quantities for a single batch of samples by continuous-flow isotope-ratio mass spectrometry (CF-IRMS) without any cumbersome and time-consuming pretreatments. The analytical system consisted of a vacuum line to extract and purify N2O, a gas chromatograph for further purification of N2O, an optional thermal furnace to decompose N2O to O2, and a CF-IRMS system. We also used pneumatic valves and pneumatic actuators in the system so that we could operate it automatically with timing software on a personal computer. The analytical precision was better than 0.12 per thousand for delta15N with >4 nmol N2O injections, 0.25 per thousand for delta18O with >4 nmol N2O injections, and 0.20 per thousand for Delta17O with >20 nmol N2O injections for a single measurement. We were also easily able to improve the precision (standard errors) to better than 0.05 per thousand for delta15N, 0.10 per thousand for delta18O, and 0.10 per thousand for Delta17O through multiple analyses with more than four repetitions with 190 nmol samples using the automated analytical system. Using the system, the delta15N, delta18O, and Delta17O values of N2O can be quantified not only for atmospheric samples, but also for other gas or liquid samples with low N2O content, such as soil gas or natural water. Here, we showed the first ever Delta17O measurements of soil N2O.
Collapse
Affiliation(s)
- Daisuke D Komatsu
- Earth and Planetary System Sciences, Faculty of Science, Hokkaido University, N10 W8, Sapporo 060-0810, Japan.
| | | | | | | |
Collapse
|
9
|
Isotope Effects in Photodissociation: Chemical Reaction Dynamics and Implications for Atmospheres. ADVANCES IN QUANTUM CHEMISTRY 2008. [DOI: 10.1016/s0065-3276(07)00207-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
10
|
Affiliation(s)
- Mao‐Chang Liang
- Research Center for Environmental Changes Academia Sinica Taipei Taiwan
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena California USA
| | - Yuk L. Yung
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena California USA
| |
Collapse
|
11
|
Liang MC, Blake GA, Lewis BR, Yung YL. Oxygen isotopic composition of carbon dioxide in the middle atmosphere. Proc Natl Acad Sci U S A 2007; 104:21-5. [PMID: 17190796 PMCID: PMC1749325 DOI: 10.1073/pnas.0610009104] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The isotopic composition of long-lived trace molecules provides a window into atmospheric transport and chemistry. Carbon dioxide is a particularly powerful tracer, because its abundance remains >100 parts per million by volume (ppmv) in the mesosphere. Here, we successfully reproduce the isotopic composition of CO(2) in the middle atmosphere, which has not been previously reported. The mass-independent fractionation of oxygen in CO(2) can be satisfactorily explained by the exchange reaction with O((1)D). In the stratosphere, the major source of O((1)D) is O(3) photolysis. Higher in the mesosphere, we discover that the photolysis of (16)O(17)O and (16)O(18)O by solar Lyman-alpha radiation yields O((1)D) 10-100 times more enriched in (17)O and (18)O than that from ozone photodissociation at lower altitudes. This latter source of heavy O((1)D) has not been considered in atmospheric simulations, yet it may potentially affect the "anomalous" oxygen signature in tropospheric CO(2) that should reflect the gross carbon fluxes between the atmosphere and terrestrial biosphere. Additional laboratory and atmospheric measurements are therefore proposed to test our model and validate the use of CO(2) isotopic fractionation as a tracer of atmospheric chemical and dynamical processes.
Collapse
Affiliation(s)
- Mao-Chang Liang
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
| | | | | | | |
Collapse
|
12
|
Prakash MK, Marcus RA. Three-isotope plot of fractionation in photolysis: A perturbation theoretical expression. J Chem Phys 2005; 123:174308. [PMID: 16375529 DOI: 10.1063/1.2102908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The slope of the three-isotope plot for the isotopomer fractionation by direct or nearly direct photodissociation is obtained using a perturbation theoretical analysis. This result, correct to first order in the mass difference, is the same as that for equilibrium chemical exchange reactions, a similarity unexpected a priori. A comparison is made with computational results for N2O photodissociation. This theoretical slope for mass-dependent photolytic fractionation can be used to analyze the data for isotopic anomalies in spin-allowed photodissociation reactions. Earlier work on chemical equilibria is extended by avoiding a high-temperature approximation.
Collapse
Affiliation(s)
- M K Prakash
- Noyes Laboratory of Chemical Physics MC 127-72, California Institute of Technology, Pasadena, California 91125, USA.
| | | |
Collapse
|
13
|
Prakash MK, Weibel JD, Marcus RA. Isotopomer fractionation in the UV photolysis of N2O: Comparison of theory and experiment. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jd006127] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
14
|
Kaiser J, Röckmann T, Brenninkmeijer CAM. Contribution of mass-dependent fractionation to the oxygen isotope anomaly of atmospheric nitrous oxide. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd004088] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jan Kaiser
- Department of Geosciences; Princeton University; Princeton New Jersey USA
| | - Thomas Röckmann
- Atmospheric Physics Division; Max Planck Institute for Nuclear Physics; Heidelberg Germany
| | | |
Collapse
|
15
|
Liang MC. A semianalytic model for photo-induced isotopic fractionation in simple molecules. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004jd004539] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
16
|
McLinden CA. Global modeling of the isotopic analogues of N2O: Stratospheric distributions, budgets, and the17O–18O mass-independent anomaly. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jd002560] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
17
|
Kaiser J. Complete and accurate mass spectrometric isotope analysis of tropospheric nitrous oxide. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003jd003613] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
18
|
|
19
|
Estupiñán EG, Nicovich JM, Li J, Cunnold DM, Wine PH. Investigation of N2O Production from 266 and 532 nm Laser Flash Photolysis of O3/N2/O2 Mixtures. J Phys Chem A 2002. [DOI: 10.1021/jp014242c] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- E. G. Estupiñán
- School of Earth and Atmospheric Sciences and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - J. M. Nicovich
- School of Earth and Atmospheric Sciences and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - J. Li
- School of Earth and Atmospheric Sciences and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - D. M. Cunnold
- School of Earth and Atmospheric Sciences and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - P. H. Wine
- School of Earth and Atmospheric Sciences and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| |
Collapse
|
20
|
Johnson MS, Billing GD, Gruodis A, Janssen MHM. Photolysis of Nitrous Oxide Isotopomers Studied by Time-Dependent Hermite Propagation. J Phys Chem A 2001. [DOI: 10.1021/jp011449x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew S. Johnson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark, Department of General Physics and Spectroscopy, University of Vilnius, Sauletekio 9, b. 3, 2040 Vilnius, Lithuania, and Laser Centre and Department of Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Gert Due Billing
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark, Department of General Physics and Spectroscopy, University of Vilnius, Sauletekio 9, b. 3, 2040 Vilnius, Lithuania, and Laser Centre and Department of Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Alytis Gruodis
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark, Department of General Physics and Spectroscopy, University of Vilnius, Sauletekio 9, b. 3, 2040 Vilnius, Lithuania, and Laser Centre and Department of Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Maurice H. M. Janssen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark, Department of General Physics and Spectroscopy, University of Vilnius, Sauletekio 9, b. 3, 2040 Vilnius, Lithuania, and Laser Centre and Department of Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
21
|
Łapiński A, Spanget-Larsen J, Waluk J, Radziszewski JG. Vibrations of nitrous oxide: Matrix isolation Fourier transform infrared spectroscopy of twelve N2O isotopomers. J Chem Phys 2001. [DOI: 10.1063/1.1383031] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Toyoda S, Yoshida N, Urabe T, Aoki S, Nakazawa T, Sugawara S, Honda H. Fractionation of N2O isotopomers in the stratosphere. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jd900680] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
23
|
Estupiñán E, Stickel R, Wine P. An investigation of N2O production from quenching of OH(A2Σ+) by N2. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00082-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
24
|
Assonov SS, Brenninkmeijer CA. A new method to determine the 17O isotopic abundance in CO2 using oxygen isotope exchange with a solid oxide. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2001; 15:2426-2437. [PMID: 11746914 DOI: 10.1002/rcm.529] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper discusses a simple method to determine 17O isotope excess or deficiency ('mass-independent isotopic composition') in CO2 gas. When applying conventional mass spectrometry of CO2 (m/z 44, 45 and 46) to determine the 17O/16O ratio, the 13C/12C ratio has to be established separately. This can be achieved by analysing an aliquot of sample CO2 before and after subjecting it to oxygen isotope exchange with a pool of oxygen with 'normal' 17O/16O ratio, i.e. with Delta17O approximately equal to delta17O-0.516 x delta18O = 0. Cerium oxide has been shown to be practically well suited for the exchange of CO2 oxygen; the reagent is safe and does not produce any contamination. The CO2-CeO2 exchange reaction has 99.8 +/- 0.7% recovery yield. At 650 degrees C this reaction reaches equilibrium in 30 min and, as tested, results in complete oxygen replacement. Delta17O determinations depend on accuracy of CO2 delta measurements: the repeatability of +/-0.015 per thousand (1sigma) in delta(45)R and delta(46)R determination relative to the working reference results in an error of Delta17O as small as +/-0.33 per thousand. Such a precision is sufficient for Delta17O determination in stratospheric CO2. The calculated Delta17O value systematically depends on absolute 17R and 13R ratios in isotopic reference materials, which are presently not yet known with certainty (the 17R value is most important), and may be inadequate for 17O-correction with a = 0.516. Within the present uncertainty, Delta17O determined in 17O-enriched CO2 agrees with the value directly measured in the enriched O2 from which this CO2 was produced. Besides Delta17O determination, investigated CO2-CeO2 equilibration may have several other implications. Fast, complete isotopic exchange of CO2 by reaction with CeO2 may also be employed to get reproducible 17O-correction and, hence, to better monitor small delta13C shifts and to isotopically equilibrate mixtures of CO2 gases.
Collapse
Affiliation(s)
- S S Assonov
- Air Chemistry Division, Max Planck Institute of Chemistry, P.O. Box 3060, 55020 Mainz, Germany.
| | | |
Collapse
|
25
|
|
26
|
|
27
|
Estupiñán E, Stickel R, Wine P. Is quenching of electronically excited NO2 by N2 an important atmospheric source of N2O? ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1465-9972(00)00014-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
28
|
|
29
|
Constraining the atmospheric N2O budget from intramolecular site preference in N2O isotopomers. Nature 2000; 405:330-4. [PMID: 10830958 DOI: 10.1038/35012558] [Citation(s) in RCA: 258] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nitrous oxide (N2O) is an important trace gas in the atmosphere. It is an active greenhouse gas in the troposphere and it also controls ozone concentration in the stratosphere through nitric oxide production. One way to trace the geochemical cycle of N2O is by measuring the natural abundance of stable isotopes, namely 15N and 18O (refs 2-15). Here we report the intramolecular distribution of 15N within the linear NNO molecule, determined by measuring molecular and fragment ions of N2O on a modified mass spectrometer. This revealed a preference for 15N at the central N position, or alpha-site, within N2O isotopomers (isotope-containing molecules). Moreover, this preference varied significantly throughout the atmosphere. In the troposphere, low alpha-site preference indicates local emission of N2O from soils and fossil-fuel combustion, each with distinct isotopomer signatures, which then mixes with background N2O. In the stratosphere, on the other hand, loss of N2O is observed as enhanced alpha-site preference for 15N, due to fractionation during ultraviolet photolysis of N2O. We have constructed an atmospheric mass balance of N2O, incorporating isotopomer abundance, which shows that the intramolecular distribution of 15N is a parameter that has the potential to increase significantly the resolution with which sources and sinks of N2O can be identified and quantified in the atmosphere.
Collapse
|
30
|
Brenninkmeijer CA, Rockmann T. Mass spectrometry of the intramolecular nitrogen isotope distribution of environmental nitrous oxide using fragment-ion analysis. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 1999; 13:2028-2033. [PMID: 10510416 DOI: 10.1002/(sici)1097-0231(19991030)13:20<2028::aid-rcm751>3.0.co;2-j] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mass spectrometry is applied to measure the intramolecular distribution of (15)N in N(2)O samples of near natural isotopic composition. The method is relatively straightforward and based on the analysis of the (14)NO and (15)NO fragment ion beams at mass 30 and 31, respectively, in combination with the standard analysis of the masses 44, 45, and 46 of the non-fragmented N(2)O. Various complications in the application, not all of which are resolved at present, are discussed. Copyright 1999 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- CA Brenninkmeijer
- Max Planck Institute for Chemistry, Atmospheric Chemistry Division, Mainz, Germany
| | | |
Collapse
|