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Horst A, Bonifacie M, Bardoux G, Richnow HH. Isotopic Characterization ( 2H, 13C, 37Cl, 81Br) of Abiotic Degradation of Methyl Bromide and Methyl Chloride in Water and Implications for Future Studies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8813-8822. [PMID: 31286766 DOI: 10.1021/acs.est.9b02165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Methyl bromide (CH3Br) and methyl chloride (CH3Cl) significantly contribute to stratospheric ozone depletion. The atmospheric budgets of both compounds are unbalanced with known degradation processes outweighing known emissions. Stable isotope analysis may be capable to identify and quantify emissions and to achieve a balanced budget. Degradation processes do, however, cause isotope fractionation in methyl halides after emission and hence knowledge about these processes is a crucial prerequisite for any isotopic mass balance approach. In the current study, triple-element isotope analysis (2H, 13C, 37Cl/81Br) was applied to investigate the two main abiotic degradation processes of methyl halides (CH3X) in fresh and seawater: hydrolysis and halide exchange. For CH3Br, nucleophilic attack by both H2O and Cl- caused significant primary carbon and bromine isotope effects accompanied by a secondary inverse hydrogen isotope effect. For CH3Cl only nucleophilic substitution by H2O was observed at significant rates causing large primary carbon and chlorine isotope effects and a secondary inverse hydrogen isotope effect. Observed dual-element isotope ratios differed slightly from literature values for microbial degradation in water and hugely from radical reactions in the troposphere. This bodes well for successfully distinguishing and quantifying degradation processes in atmospheric methyl halides using triple-element isotope analysis.
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Affiliation(s)
- Axel Horst
- Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Permoserstr.15 , 04318 Leipzig , Germany
| | - Magali Bonifacie
- Institut de Physique du Globe de Paris , Sorbonne Paris Cité, Université Paris-Diderot, UMR 7154 CNRS , 1 rue Jussieu , F-75005 Paris , France
| | - Gérard Bardoux
- Institut de Physique du Globe de Paris , Sorbonne Paris Cité, Université Paris-Diderot, UMR 7154 CNRS , 1 rue Jussieu , F-75005 Paris , France
| | - Hans Hermann Richnow
- Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Permoserstr.15 , 04318 Leipzig , Germany
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Thornton BF, Horst A, Carrizo D, Holmstrand H. Methyl chloride and methyl bromide emissions from baking: an unrecognized anthropogenic source. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 551-552:327-33. [PMID: 26878644 DOI: 10.1016/j.scitotenv.2016.01.213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 01/30/2016] [Accepted: 01/31/2016] [Indexed: 05/21/2023]
Abstract
Methyl chloride and methyl bromide (CH3Cl and CH3Br) are the largest natural sources of chlorine and bromine, respectively, to the stratosphere, where they contribute to ozone depletion. We report the anthropogenic production of CH3Cl and CH3Br during breadbaking, and suggest this production is an abiotic process involving the methyl ester functional groups in pectin and lignin structural polymers of plant cells. Wide variations in baking styles allow only rough estimates of this flux of methyl halides on a global basis. A simple model suggests that CH3Br emissions from breadbaking likely peaked circa 1990 at approximately 200tonnes per year (about 0.3% of industrial production), prior to restrictions on the dough conditioner potassium bromate. In contrast, CH3Cl emissions from breadbaking may be of similar magnitude as acknowledged present-day CH3Cl industrial emissions. Because the mechanisms involve functional groups and compounds widely found in plant materials, this type of methyl halide production may occur in other cooking techniques as well.
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Affiliation(s)
- Brett F Thornton
- Department of Geological Sciences, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden; Bolin Centre for Climate Research, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden.
| | - Axel Horst
- Department of Analytical Chemistry and Environmental Science, Stockholm University, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden
| | - Daniel Carrizo
- Department of Analytical Chemistry and Environmental Science, Stockholm University, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden
| | - Henry Holmstrand
- Bolin Centre for Climate Research, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden; Department of Analytical Chemistry and Environmental Science, Stockholm University, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden
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Blessing M, Jochmann MA, Haderlein SB, Schmidt TC. Optimization of a large-volume injection method for compound-specific isotope analysis of polycyclic aromatic compounds at trace concentrations. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:2349-2360. [PMID: 26563706 DOI: 10.1002/rcm.7389] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/02/2015] [Accepted: 09/07/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE Compound-specific isotope analysis (CSIA) of persistent organic contaminants can be used for source apportioning in the environment if appropriate sensitivity can be achieved. This paper describes the optimization and validation of a sensitive analytical approach for the determination of the carbon isotope composition of semi-volatile organic compounds, such as polycyclic aromatic hydrocarbons (PAHs). METHODS Analyses are based on the introduction of up to 150 μL of organic extracts by means of programmed temperature vaporization-large-volume injection combined with gas chromatography coupled to isotope ratio mass spectrometry (PTV-LVI-GC/IRMS). To allow for the analysis of more volatile, low-molecular-weight PAHs, the PTV injector was equipped with a sub-ambient/cryogenic cooling. Accuracy, precision, linearity and determination limits for application in isotope analysis were evaluated for a set of individual PAHs ranging from two- to five-ring molecular structures. The method was exemplified by determining the δ(13) C values of individual PAHs in soil samples in a source apportionment study at a contaminated site. RESULTS The choice of PTV injection parameters is crucial to prevent isotope fractionation during injection and largely depends on the analytes to be determined. The observed isotope fractionation effect on semi-volatiles depends on the applied solvent and injection temperature and demonstrates the importance of performing appropriate tests with given PTV parameters for each of the compounds of interest. The proposed PTV-LVI-GC/IRMS method allows the carbon isotope ratio (δ(13) C value) of individual PAHs to be determined accurately and precisely at concentrations of 0.04-0.1 ng μL(-1) even for volatile PAHs such as naphthalene or acenaphthene. CONCLUSIONS LVI with PTV injector cooling allows for the isotopic analysis of volatile and semi-volatile PAHs at trace concentrations, thus considerably expanding the applicability of CSIA in environmental studies.
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Affiliation(s)
- Michaela Blessing
- BRGM, LAB/ISO, 3 avenue Claude Guillemin, BP 36009, F-45060, Orléans cedex 2, France
| | - Maik A Jochmann
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstr. 5, D-45141, Essen, Germany
| | - Stefan B Haderlein
- Center for Applied Geoscience (ZAG), Eberhard Karls University Tübingen, Hölderlinstr. 12, D-72076, Tübingen, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstr. 5, D-45141, Essen, Germany
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Miller LG, Baesman SM, Oremland RS. Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s. ASTROBIOLOGY 2015; 15:977-86. [PMID: 26539733 PMCID: PMC4653830 DOI: 10.1089/ast.2015.1355] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
UNLABELLED We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. KEY WORDS Acetylene-Fermentation-Isotope fractionation-Enceladus-Life detection.
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Horst A, Holmstrand H, Andersson P, Andersson A, Carrizo D, Thornton BF, Gustafsson O. Compound-specific bromine isotope analysis of methyl bromide using gas chromatography hyphenated with inductively coupled plasma multiple-collector mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:2425-2432. [PMID: 21818801 DOI: 10.1002/rcm.5144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Methyl bromide is the most important natural bromine contributor to stratospheric ozone depletion, yet there are still large uncertainties regarding quantification of its sources and sinks. The stable bromine isotope composition of CH(3)Br is potentially a powerful tool to apportion its sources and to study both its transport and its reactive fate. A novel compound-specific method to measure (81)Br/(79)Br isotope ratios in CH(3)Br using gas chromatography hyphenated with inductively coupled plasma multiple-collector mass spectrometry (GC/MCICPMS) was developed. Sample amounts of >40 ng could be measured with a precision of 0.1‰ (1σ, n = 3). The method results are reproducible over the long term as shown with 36 analyses acquired over 3 months, yielding a standard deviation (1σ) better than 0.4‰. This new method demonstrates for the first time Br isotope ratio determination in gaseous brominated samples. It is three orders of magnitude more sensitive than previously existing isotope ratio mass spectrometry methods for Br isotope determination of other organobromines, thus allowing applications towards ambient atmospheric samples.
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Affiliation(s)
- Axel Horst
- Department of Applied Environmental Science (ITM), Stockholm University, Stockholm, Sweden
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Muccio Z, Jackson GP. Simultaneous Identification and δ13C Classification of Drugs Using GC with Concurrent Single Quadrupole and Isotope Ratio Mass Spectrometers*. J Forensic Sci 2010; 56 Suppl 1:S203-9. [DOI: 10.1111/j.1556-4029.2010.01594.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Redeker KR, Davis S, Kalin RM. Isotope values of atmospheric halocarbons and hydrocarbons from Irish urban, rural, and marine locations. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007784] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Schäfer H, Miller LG, Oremland RS, Murrell JC. Bacterial Cycling of Methyl Halides. ADVANCES IN APPLIED MICROBIOLOGY 2007; 61:307-46. [PMID: 17448794 DOI: 10.1016/s0065-2164(06)61009-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Hendrik Schäfer
- Department of Biological Sciences, University of Warwick, Coventry, United Kingdom
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Elsner M, Zwank L, Hunkeler D, Schwarzenbach RP. A new concept linking observable stable isotope fractionation to transformation pathways of organic pollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:6896-916. [PMID: 16201610 DOI: 10.1021/es0504587] [Citation(s) in RCA: 368] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Measuring stable isotope fractionation of carbon, hydrogen, and other elements by Compound Specific Isotope Analysis (CSIA) is a new, innovative approach to assess organic pollutant degradation in the environment. Central to this concept is the Rayleigh equation which relates degradation-induced decreases in concentrations directly to concomitant changes in bulk (= average over the whole compound) isotope ratios. The extent of in situ transformation may therefore be inferred from measured isotope ratios in field samples, provided that an appropriate enrichment factor (epsilonbulk) is known. This epsilonbulk value, however, is usually only valid for a specific compound and for specific degradation conditions. Therefore, a direct comparison of epsilonbulk values for different compounds and for different types of reactions has in general not been feasible. In addition, it is often uncertain how robust and reproducible epsilonbulk values are and how confidently they can be used to quantify contaminant degradation in the field. To improve this situation and to achieve a more in-depth understanding, this critical review aims to relate fundamental insight about kinetic isotope effects (KIE) found in the physico(bio)chemical literature to apparent kinetic isotope effects (AKIE) derived from epsilonbulk values reported in environmentally oriented studies. Starting from basic rate laws, a quite general derivation of the Rayleigh equation is given, resulting in a novel set of simple equations that take into account the effects of (1) nonreacting positions and (2) intramolecular competition and that lead to position-specific AKIE values rather than bulk enrichment factors. Reevaluation of existing epsilonbulk literature values result in consistent ranges of AKIE values that generally are in good agreement with previously published data in the (bio)-chemical literature and are typical of certain degradation reactions (subscripts C and H indicate values for carbon and hydrogen): AKIEc = 1.01-1.03 and AKIEH = 2-23 for oxidation of C-H bonds; AKIEc = 1.03-1.07 for SN2-reactions; AKIEc = 1.02-1.03 for reductive cleavage of C-Cl bonds; AKIEc = 1.00-1.01 for C=C bond epoxidation; AKIEc = 1.02-1.03 for C=C bond oxidation by permanganate. Hence, the evaluation scheme presented bridges a gap between basic and environmental (bio)chemistry and provides insight into factors that control the magnitude of bulk isotope fractionation factors. It also serves as a basis to identify degradation pathways using isotope data. It is shown how such an analysis may be even possible in complex field situations and/or in cases where AKIE values are smaller than intrinsic KIE values, provided that isotope fractionation is measured for two elements simultaneously ("two-dimensional isotope analysis"). Finally, the procedure is used (1) to point outthe possibility of estimating approximate epsilonbulk values for new compounds and (2) to discuss the moderate, but non-negligible variability that may quite generally be associated with epsilonbulk values. Future research is suggested to better understand and take into account the various factors that may cause such variability.
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Affiliation(s)
- Martin Elsner
- Swiss Federal Institute for Environmental Science and Technology (EAWAG), CH-8600 Duebendorf, Switzerland.
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Archbold ME, Redeker KR, Davis S, Elliot T, Kalin RM. A method for carbon stable isotope analysis of methyl halides and chlorofluorocarbons at pptv concentrations. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:337-342. [PMID: 15645502 DOI: 10.1002/rcm.1791] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A pre-concentration system has been validated for use with a gas chromatography/mass spectrometry/isotope ratio mass spectrometer (GC/MS/IRMS) to determine ambient air (13)C/(12)C ratios for methyl halides (MeCl and MeBr) and chlorofluorocarbons (CFCs). The isotopic composition of specific compounds can provide useful information on their atmospheric budgets and biogeochemistry that cannot be ascertained from abundance measurements alone. Although pre-concentration systems have been previously used with a GC/MS/IRMS for atmospheric trace gas analysis, this is the first study also to report system validation tests. Validation results indicate that the pre-concentration system and subsequent separation technologies do not significantly alter the stable isotopic ratios of the target methyl halides, CFC-12 (CCl(2)F(2)) and CFC-113 (C(2)Cl(3)F(3)). Significant, but consistent, isotopic shifts of -27.5 per thousand to -25.6 per thousand do occur within the system for CFC-11 (CCl(3)F), although the shift is correctible. The method presented has the capacity to separate these target halocarbons from more than 50 other compounds in ambient air samples. Separation allows for the determination of stable carbon isotope ratios of five of these six target trace atmospheric constituents within ambient air for large volume samples (</=10 L). Representative urban air analyses from Belfast City are also presented which give carbon isotope results similar to published values for (13)C/(12)C analysis of MeCl (-39.1 per thousand) and CFC-113 (-28.1 per thousand). However, this is the first paper reporting stable carbon isotope signatures for CFC-11 (-29.4 per thousand) and CFC-12 (-37.0 per thousand).
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Affiliation(s)
- Marie E Archbold
- Environmental Engineering Research Centre, School of Civil Engineering, Queen's University of Belfast, David Keir Building, Stranmillis Rd., Belfast BT9 5AG, UK.
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Goldstein AH, Shaw SL. Isotopes of Volatile Organic Compounds: An Emerging Approach for Studying Atmospheric Budgets and Chemistry. Chem Rev 2003; 103:5025-48. [PMID: 14664642 DOI: 10.1021/cr0206566] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA.
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Harper DB, Hamilton JTG, Ducrocq V, Kennedy JT, Downey A, Kalin RM. The distinctive isotopic signature of plant-derived chloromethane: possible application in constraining the atmospheric chloromethane budget. CHEMOSPHERE 2003; 52:433-436. [PMID: 12738266 DOI: 10.1016/s0045-6535(03)00206-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Chloromethane (CH(3)Cl) is the most abundant halocarbon in the atmosphere. Although largely of natural origin it is responsible for around 17% of chlorine-catalysed ozone destruction. Sources identified to date include biomass burning, oceanic emissions, wood-rotting fungi, higher plants and most recently tropical ferns. Current estimates reveal a shortfall of around 2 million ty(-1) in sources versus sinks for the halocarbon. It is possible that emissions from green plants have been substantially underestimated. A potentially valuable tool for validating emission flux estimates is comparison of the delta13C value of atmospheric CH(3)Cl with those of CH(3)Cl from the various sources. Here we report delta13C values for CH(3)Cl released by two species of tropical ferns and show that the isotopic signature of CH(3)Cl from pteridophytes like that of CH(3)Cl from higher plants is quite different from that of CH(3)Cl produced by biomass burning, fungi and industry. delta13C values for CH(3)Cl produced by Cyathea smithii and Angiopteris evecta were respectively -72.7 per thousand and -69.3 per thousand representing depletions relative to plant biomass of 42.3 per thousand and 43.4 per thousand. The characteristic isotopic signature of CH(3)Cl released by green plants should help constrain their contribution to the atmospheric burden when reliable delta13C values for all other major sources of CH(3)Cl are obtained and a globally averaged delta13C value for atmospheric CH(3)Cl is available.
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Affiliation(s)
- D B Harper
- School of Agriculture and Food Science, The Queen's University of Belfast, Newforge Lane, Belfast BT9 5PX, UK.
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Harper DB, Kalin RM, Hamilton JT, Lamb C. Carbon isotope ratios for chloromethane of biological origin: potential tool in determining biological emissions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:3616-3619. [PMID: 11783636 DOI: 10.1021/es0106467] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chloromethane (CH3Cl) with a global atmospheric burden of 5.3 million t is the most abundant halocarbon in the atmosphere. However, the origin of ca. 50% of the estimated annual global input of 4 million t of the gas to the atmosphere has yet to be determined. As the oceanic contribution to the global CH3Cl flux is now tightly constrained, an important terrestrial source is either underestimated or unrecognized. It has recently been proposed that higher plants may represent a CH3Cl source of sufficient magnitude to resolve the global budget imbalance. A potentially useful tool in validating CH3Cl emission flux estimates is comparison of the carbon isotope ratio of atmospheric CH3Cl with those of CH3Cl originating from various sources. Here we report the first measurements of delta13C for CH3Cl produced biologically. The CH3Cl released by the higher plant species Batis maritima and Solanum tuberosum was dramatically depleted in 13C with respect to plant tissue (delta13C = -36.8/1000 and -34.5/1000, respectively); CH3Cl released by the fungus Phellinus pomaceus also showed significant 13C depletion with respect to the wood growth substrate (delta13C = -17.9/1000). When reliable delta13C values for the other major sources of atmospheric CH3Cl become available, the distinctive isotopic signature of plant-derived CH3Cl should help constrain the contribution to the atmospheric burden from this source.
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Affiliation(s)
- D B Harper
- Microbial Biochemistry Section, School of Agriculture and Food Science, The Queen's University of Belfast, UK.
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Hamill NA, Hardacre C, Barth JA, Kalin RM, Cunningham JF. Gas-phase photocatalytic oxidation of dichlorobutenes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:2823-2827. [PMID: 11452616 DOI: 10.1021/es001939n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Gas-phase photocatalysis of 1,4-dichlorobut-2-enes and 3,4-dichlorobut-1-ene (DCB) has been studied using TiO2 and 3% WO3/TiO2 supported on SiO2. DCB was found to oxidize efficiently over these catalysts; however, only low rates of CO2 formation were observed. With these chlorinated hydrocarbons, the catalysts were found to deactivate over time, probably via the formation of aldol condensation products of chloracetaldehyde, which is the predominant intermediate observed. The variation in rate and selectivity of the oxidation reactions with O2 concentration is reported and a mechanism is proposed. Using isotope ratio mass spectrometry, the initial step for the DCB removal has been shown not to be a carbon bond cleavage but is likely to be hydroxyl radical addition to the carbon-carbon double bond.
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Affiliation(s)
- N A Hamill
- School of Chemistry, David Keir Building, Queen's University of Belfast, Belfast BT9 5AG, Northern Ireland, U.K
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Miller LG, Kalin RM, McCauley SE, Hamilton JT, Harper DB, Millet DB, Oremland RS, Goldstein AH. Large carbon isotope fractionation associated with oxidation of methyl halides by methylotrophic bacteria. Proc Natl Acad Sci U S A 2001; 98:5833-7. [PMID: 11344313 PMCID: PMC33299 DOI: 10.1073/pnas.101129798] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2000] [Accepted: 03/13/2001] [Indexed: 11/18/2022] Open
Abstract
The largest biological fractionations of stable carbon isotopes observed in nature occur during production of methane by methanogenic archaea. These fractionations result in substantial (as much as approximately 70 per thousand) shifts in delta(13)C relative to the initial substrate. We now report that a stable carbon isotopic fractionation of comparable magnitude (up to 70 per thousand) occurs during oxidation of methyl halides by methylotrophic bacteria. We have demonstrated biological fractionation with whole cells of three methylotrophs (strain IMB-1, strain CC495, and strain MB2) and, to a lesser extent, with the purified cobalamin-dependent methyltransferase enzyme obtained from strain CC495. Thus, the genetic similarities recently reported between methylotrophs, and methanogens with respect to their pathways for C(1)-unit metabolism are also reflected in the carbon isotopic fractionations achieved by these organisms. We found that only part of the observed fractionation of carbon isotopes could be accounted for by the activity of the corrinoid methyltransferase enzyme, suggesting fractionation by enzymes further along the degradation pathway. These observations are of potential biogeochemical significance in the application of stable carbon isotope ratios to constrain the tropospheric budgets for the ozone-depleting halocarbons, methyl bromide and methyl chloride.
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Affiliation(s)
- L G Miller
- United States Geological Survey, Menlo Park, CA 94025, USA.
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Current awareness. Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:581-588. [PMID: 11391815 DOI: 10.1002/jms.92] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (3 Weeks journals - Search completed at 7th. Mar. 2001)
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