QSA influences on isotopic ratio measurements

Slodzian, G.; Hillion, F.; Stadermann, F. J.; Zinner, E.

doi:10.1016/j.apsusc.2004.03.155

Cited by 91 publications

(70 citation statements)

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“…The nanoSIMS has previously been used to analyze sulfur isotopes in minerals (Slodzian et al, 2004;Hoppe et al, 2005) and carbon, nitrogen and sulfur distributions in biological samples (Clode et al, 2007;Li et al, 2008). For the present study, data were obtained using electron multiplier multi-collection, operating with the cesium (Cs þ ) ion source.…”

Section: Nanosims Analysis and Isotopic Calibrationmentioning

confidence: 99%

“…However, there was no observed temporal trend in the isotope ratio of sulfide (Supplemental Figure S3), strongly suggesting that the decreasing yield did not cause an isotopic offset in the data. The nanoSIMS-generated data set was also examined for evidence of a quasisimultaneous arrival (QSA) effect, which has been suggested to generate isotopic fractionations during sulfur isotope (and other) measurements made using electron multipliers on the nanoSIMS (Slodzian et al, 2004). Operating conditions (Ko0.0025) indicate that any correction would have been minimal (o2%), and no evidence for this effect was observed in analysis of 4300 data points.…”

Section: Nanosims Analysis and Isotopic Calibrationmentioning

confidence: 99%

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Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

et al. 2008

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The metabolic activities of microbial mats have likely regulated biogeochemical cycling over most of Earth's history. However, the relationship between metabolic activity and the establishment of isotopic geochemical gradients in these mats remains poorly constrained. Here we present a parallel microgeochemical and microbiological study of micron-scale sulfur cycling within hypersaline microbial mats from Guerrero Negro, Baja California Sur, Mexico. Dissolved sulfide within the mats was captured on silver discs and analyzed for its abundance and d 34 S isotopic composition using high-resolution secondary ion mass spectrometry (nanoSIMS). These results were compared to sulfide and oxygen microelectrode profiles. Two-dimensional microgeochemical mapping revealed well-defined laminations in sulfide concentration (on scales from 1 to 200 lm), trending toward increased sulfide concentrations at depth. Sulfide d 34 S decreased from B þ 10% to À20% in the uppermost 3 mm and oscillated repeatedly between À10% and À30% down to a depth of 8 mm. These variations are attributed to spatially variable bacterial sulfate reduction within the mat. A parallel examination of the spatial distribution of known sulfate-reducing bacteria within the family Desulfobacteraceae was conducted using catalyzed reporter deposition fluorescence in situ hybridization. Significant concentrations of Desulfobacteraceae were observed in both oxic and anoxic zones of the mat and occurred in several distinct layers, in large aggregates and heterogeneously dispersed as single cells throughout. The spatial distribution of these microorganisms is consistent with the variation in sulfide concentration and isotopic composition we observed. The parallel application of the methodologies developed here can shed light on micronscale sulfur cycling within microbially dominated sedimentary environments.

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Section: Nanosims Analysis and Isotopic Calibrationmentioning

confidence: 99%

Section: Nanosims Analysis and Isotopic Calibrationmentioning

confidence: 99%

Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

et al. 2008

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“…Correction for the quasi-simultaneous arrival (QSA) effect was carried out as described by Slodzian et al (2004), however a factor of 0.75 rather than 0.69 was used as this minimised the dependence on count rate best for these samples.…”

Section: Nanosimsmentioning

confidence: 99%

Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

et al. 2012

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Abstract. The oxidation of SO 2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO 2 : Gas-phase oxidation by OH radicals, and aqueous oxidation by H 2 O 2 , O 3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34 S/ 32 S during the gas-phase reaction is α OH = (1.0089±0.0007) − ((4±5)×10 −5 )T ( • C). The measured fractionation factor for 34 S/ 32 S during aqueous oxidation by H 2 O 2 or O 3 is α aq = (1.0167±0.0019) − ((8.7±3.5)×10 −5 )T ( • C). The observed fractionation during oxidation by H 2 O 2 and O 3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV) in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is α Fe = (0.9894±0.0043) at 19 • C for 34 S/ 32 S. Fractionation was mass-dependent with regards to 33 S/ 32 S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone.

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“…Isotope ratios were determined with the L'Image software developed by L. Nittler, Carnegie Institution of Washington, DC. One could expect the quasi-simultaneous arrival (QSA) effect on C isotopes (Slodzian et al 2004). However, in our experiments, no variations of the instrumental fractionation factor with count rates were observed.…”

Section: Samples and Analytical Methodsmentioning

confidence: 99%

Isotopic fractionation of oxygen and carbon in decomposed lower-mantle inclusions in diamond

Kaminsky¹,

Matzel

Jacobsen

et al. 2015

Miner Petrol

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Two carbonatitic mineral assemblages, calcite + wollastonite and calcite + monticellite, which are encapsulated in two diamond grains from the Rio Soriso basin in the Juina area, Mato Grosso State, Brazil, were studied utilizing the NanoSIMS technique. The assemblages were formed as the result of the decomposition of the lower-mantle assemblage calcite + CaSi-perovskite + volatile during the course of the diamond ascent under pressure conditions from 15 to less than 0.8 GPa. The oxygen and carbon isotopic compositions of the studied minerals are inhomogeneous. They fractionated during the process of the decomposition of primary minerals to very varying values: δ 18 O from -3.3 ‰ to +15.4 ‰ SMOW and δ 13 C from -2.8 ‰ to +9.3 ‰ VPDB. These values significantly extend the mantle values for these elements in both isotopically-light and isotopically-heavy areas.

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QSA influences on isotopic ratio measurements

Cited by 91 publications

References 1 publication

Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H<sub>2</sub>O<sub>2</sub>, O<sub>3</sub> and iron catalysis

Isotopic fractionation of oxygen and carbon in decomposed lower-mantle inclusions in diamond

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QSA influences on isotopic ratio measurements

Cited by 91 publications

References 1 publication

Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

Micron-scale mapping of sulfur cycling across the oxycline of a cyanobacterial mat: a paired nanoSIMS and CARD-FISH approach

Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt; and iron catalysis

Isotopic fractionation of oxygen and carbon in decomposed lower-mantle inclusions in diamond

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Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H<sub>2</sub>O<sub>2</sub>, O<sub>3</sub> and iron catalysis