New Guidelines for δ13C Measurements

Coplen, Tyler B.; Brand, Willi A.; Gehre, Matthias; Gröning, Manfred; Meijer, H. A. J.; Toman, Blaza; Verkouteren, R. Michael

doi:10.1021/ac052027c

Cited by 795 publications

(664 citation statements)

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“…In this study, the term "calibration" means to measure a laboratory gas (for instance a laboratory working standard gas that is routinely compared with samples) against a standard at higher hierarchy level and to assign to that working standard a δ 13 C-CH 4 or δD-CH 4 value traceable to the standard scale. In principle, all measurements at individual laboratories intend to ultimately anchor their working standards and sample gases to the VPDB or VSMOW scale using the RMs provided by the International Atomic Energy Agency (IAEA) or National Institute of Standards and Technology (NIST; Coplen et al, 2006;Brand et al, 2014). However, since RMs and recommended calibration methods for measurements of δ 13 C-CH 4 and δD-CH 4 in air have not yet been provided (Sperlich et al, 2012, individual groups have developed their own calibration strategies.…”

Section: Standard Scalesmentioning

confidence: 99%

“…Despite intentions of best traceability to RMs, the variety of calibrations has resulted in diverse realizations of the VPDB scale across δ 13 C-CH 4 measurement programmes. As in Table 1, the different RMs that have been applied to δ 13 C-CH 4 calibration include NBS-19 (limestone), IAEA-CO-9 (barium carbonate), LSVEC (lithium carbonate) and RM 8562-8564 (CO 2 ); see Coplen et al (2006), Brand et al (2014) and Sperlich et al (2016). It is also noted that uncertainties of assigned values for these RMs range up to a few tenths per mille and the assigned values have been revised over time , which might have complicated the realization of the standard scale at each labora-tory.…”

Section: Standard Scalesmentioning

confidence: 99%

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Interlaboratory comparison of δ13C and δD measurements of atmospheric CH4 for combined use of data sets from different laboratories

et al. 2018

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Abstract. We report results from a worldwide interlaboratory comparison of samples among laboratories that measure (or measured) stable carbon and hydrogen isotope ratios of atmospheric CH 4 (δ 13 C-CH 4 and δD-CH 4 ). The offsets among the laboratories are larger than the measurement reproducibility of individual laboratories. To disentangle plausible measurement offsets, we evaluated and critically assessed a large number of intercomparison results, some of which have been documented previously in the literature. The results indicate significant offsets of δ 13 C-CH 4 and δD-CH 4 measurements among data sets reported from different laboratories; the differences among laboratories at modern atmospheric CH 4 level spread over ranges of 0.5 ‰ for δ 13 C-CH 4 and 13 ‰ for δD-CH 4 . The intercomparison results summarized in this study may be of help in future attempts to harmonize δ 13 C-CH 4 and δD-CH 4 data sets fromPublished by Copernicus Publications on behalf of the European Geosciences Union. 1208T. Umezawa et al.: Interlaboratory comparison of δ 13 C and δD measurements of CH 4 different laboratories in order to jointly incorporate them into modelling studies. However, establishing a merged data set, which includes δ 13 C-CH 4 and δD-CH 4 data from multiple laboratories with desirable compatibility, is still challenging due to differences among laboratories in instrument settings, correction methods, traceability to reference materials and long-term data management. Further efforts are needed to identify causes of the interlaboratory measurement offsets and to decrease those to move towards the best use of available δ 13 C-CH 4 and δD-CH 4 data sets.

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Section: Standard Scalesmentioning

confidence: 99%

Section: Standard Scalesmentioning

confidence: 99%

Interlaboratory comparison of δ13C and δD measurements of atmospheric CH4 for combined use of data sets from different laboratories

et al. 2018

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“…d 13 C values were measured on a Thermo Scientific Delta V Plus irMS. d 13 C and values were corrected for sample size dependency and then normalized to the VPDB scale with a two-point calibration and internal standards (Coplen et al, 2006). Accuracy was ± 0.09% (n ¼ 20) and precision was ±0.02% (n ¼ 5; 1s), determined by analyzing independent standards as samples and precision was determined from international standards.…”

Section: Carbon Elemental Analysismentioning

confidence: 99%

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Goffredi

Zhang

et al. 2013

The ISME Journal

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An unusual symbiosis, first observed at B3000 m depth in the Monterey Submarine Canyon, involves gutless marine polychaetes of the genus Osedax and intracellular endosymbionts belonging to the order Oceanospirillales. Ecologically, these worms and their microbial symbionts have a substantial role in the cycling of carbon from deep-sea whale fall carcasses. Microheterogeneity exists among the Osedax symbionts examined so far, and in the present study the genomes of the two dominant symbionts, Rs1 and Rs2, were sequenced. The genomes revealed heterotrophic versatility in carbon, phosphate and iron uptake, strategies for intracellular survival, evidence for an independent existence, and numerous potential virulence capabilities. The presence of specific permeases and peptidases (of glycine, proline and hydroxyproline), and numerous peptide transporters, suggests the use of degraded proteins, likely originating from collagenous bone matter, by the Osedax symbionts. 13 C tracer experiments confirmed the assimilation of glycine/ proline, as well as monosaccharides, by Osedax. The Rs1 and Rs2 symbionts are genomically distinct in carbon and sulfur metabolism, respiration, and cell wall composition, among others. Differences between Rs1 and Rs2 and phylogenetic analysis of chemotaxis-related genes within individuals of symbiont Rs1 revealed the influence of the relative age of the whale fall environment and support possible local niche adaptation of 'free-living' lifestages. Future genomic examinations of other horizontally-propogated intracellular symbionts will likely enhance our understanding of the contribution of intraspecific symbiont diversity to the ecological diversification of the intact association, as well as the maintenance of host diversity.

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“…The effect is most pronounced for H and O, and normalization is commonly utilized for these elements. Normalization is rarely used for C or N, though the International Atomic Energy Agency (IAEA) now recommends that all 13 C analyses be corrected for scale normalization based on two or more standards [82]. In practice, a normalization line is constructed by analyzing a suite of standards of known isotopic compositions varying over the range of expected d values.…”

Section: Calculation Of Isotope Ratiosmentioning

confidence: 99%

Isotope‐ratio detection for gas chromatography

Sessions¹

2006

J of Separation Science

236

270

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Isotope-ratio detection for gas chromatographyInstrumentation and methods exist for highly precise analyses of the stable-isotopic composition of organic compounds separated by GC. The general approach combines a conventional GC, a chemical reaction interface, and a specialized isotoperatio mass spectrometer (IRMS). Most existing GC hardware and methods are amenable to isotope-ratio detection. The interface continuously and quantitatively converts all organic matter, including column bleed, to a common molecular form for isotopic measurement. C and N are analyzed as CO 2 and N 2 , respectively, derived from combustion of analytes. H and O are analyzed as H 2 and CO produced by pyrolysis/reduction. IRMS instruments are optimized to provide intense, highly stable ion beams, with extremely high precision realized via a system of differential measurements in which ion currents for all major isotopologs are simultaneously monitored. Calibration to an internationally recognized scale is achieved through comparison of closely spaced sample and standard peaks. Such systems are capable of measuring 13 C/ 12 C ratios with a precision approaching 0.1? (for values reported in the standard delta notation), four orders of magnitude better than that typically achieved by conventional "organic" mass spectrometers. Detection limits to achieve this level of precision are typically a1 nmol C (roughly 10 ng of a typical hydrocarbon) injected on-column. Achievable precision and detection limits are correspondingly higher for N, O, and H, in that order.

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New Guidelines for δ¹³C Measurements

Cited by 795 publications

References 10 publications

Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories

Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Isotope‐ratio detection for gas chromatography

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New Guidelines for δ13C Measurements

Cited by 795 publications

References 10 publications

Interlaboratory comparison of &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;13&lt;/sup&gt;C and &lt;i&gt;δ&lt;/i&gt;D measurements of atmospheric CH&lt;sub&gt;4&lt;/sub&gt; for combined use of data sets from different laboratories

Interlaboratory comparison of &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;13&lt;/sup&gt;C and &lt;i&gt;δ&lt;/i&gt;D measurements of atmospheric CH&lt;sub&gt;4&lt;/sub&gt; for combined use of data sets from different laboratories

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Isotope‐ratio detection for gas chromatography

Contact Info

Product

Resources

About

New Guidelines for δ¹³C Measurements

Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories

Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories