Optimization of on‐line hydrogen stable isotope ratio measurements of halogen‐ and sulfur‐bearing organic compounds using elemental analyzer–chromium/high‐temperature conversion isotope ratio mass spectrometry (EA‐Cr/HTC‐IRMS)

Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

doi:10.1002/rcm.7810

Cited by 33 publications

(38 citation statements)

References 26 publications

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“…We stress that this offset is relevant for bone collagen only, since other N‐containing and halogen‐ and sulfur‐containing materials have somewhat different δ 2 H values in Cr‐packed vs glassy‐C‐packed reactors.…”

Section: Discussionmentioning

confidence: 98%

The interconversion of δ²H values of collagen between thermal conversion reactor configurations

Reynard

Ryan

Tuross

2019

Rapid Comm Mass Spectrometry

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Rationale Different thermal conversion reactor packings result in distinct δ2H values in nitrogen‐containing materials, such as bone collagen. An older ‘traditional’ glassy carbon packing method causes incomplete conversion of N‐containing samples into H2 gas, resulting in altered δ2H values compared with the complete conversion of hydrogen obtained with a chromium‐packed reactor. Given that δ2H values from collagen are gaining importance in palaeoecological and archaeological studies, a determination of the relationship between δ2H values produced with a glassy‐carbon‐packed and a chromium‐packed reactor is needed. Methods We obtained δ2H values (normalized on the VSMOW‐SLAP scale) from both glassy‐carbon‐packed (GP) and chromium‐packed (Cr) reactor configurations from bone collagen (n = 231) from a variety of archaeological sites, using a High‐Temperature Conversion Elemental Analyzer (TC/EA) coupled to a Delta Plus XP isotope ratio mass spectrometer. Results δ2H values from both methods are linearly correlated (r2 = 0.934) and yield the following interconversion equation, δ2H(Cr) = 1.054 δ2H(GP) + 11.6‰ (95% conf. slope 1.020–1.090, intercept 10.6–12.6), and a mean difference of δ2H(Cr) – δ2H(GP) = 10.1‰ (1 sd 5.2, 1 se 0.3, n = 231). Conclusions We recommend adopting this interconversion between δ2H values produced with a glassy‐carbon‐packed and chromium‐packed reactor for bone collagen only, with appropriate propagation of uncertainty.

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Section: Discussionmentioning

confidence: 98%

The interconversion of δ²H values of collagen between thermal conversion reactor configurations

Reynard

Ryan

Tuross

2019

Rapid Comm Mass Spectrometry

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“…The conversion into H 2 gas was achieved with a high‐temperature furnace (Hekatech, Wegberg, Germany) held at 1430°C that was equipped with a glassy carbon tube inside a silicon carbide tube (tube in tube design) with a reverse feed He carrier gas flow rate of ~80 mL/min. Gehre et al and Nair et al have shown that the HTC reactor should be filled with chromium when measuring the δ 2 H signature of heteroatom (N, S, F, Cl, Br, I)‐containing compounds. Chromium traps the heteroatoms and thus facilitates a quantitative conversion of analyte into H 2 gas, and subsequent transport to the isotope ratio mass spectrometer .…”

Section: Methodsmentioning

confidence: 99%

Methyl sulfates as methoxy isotopic reference materials for δ¹³C and δ²H measurements

Greule

Moossen

Geilmann

et al. 2019

Rapid Comm Mass Spectrometry

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Rationale Stable hydrogen and carbon isotope ratios of methoxy groups (OCH3) of plant organic matter have many potential applications in biogeochemical, atmospheric and food research. So far, most of the analyses of plant methoxy groups by isotope ratio mass spectrometry have employed liquid iodomethane (CH3I) as the reference material to normalise stable isotope measurements of these moieties to isotope–δ scales. However, comparisons of measurements of stable hydrogen and carbon isotopes of plant methoxy groups are still hindered by the lack of suitable reference materials. Methods We have investigated two methyl sulfate salts (HUBG1 and HUBG2), which exclusively contain carbon and hydrogen from one methoxy group, for their suitability as methoxy reference materials. Firstly, the stable hydrogen and carbon isotope values of the bulk compounds were calibrated against international reference substances by high‐temperature conversion‐ and elemental analyser isotope ratio mass spectrometry (HTC‐ and EA‐IRMS). In a second step these values were compared with values obtained by measurements using gas chromatography/isotope ratio mass spectrometry (GC/IRMS) where prior to analysis the methoxy groups were converted into gaseous iodomethane. Results The 2H‐ and 13C isotopic abundances of HUBG1 measured by HTC‐ and EA‐IRMS and expressed as δ‐values on the usual international scales are −144.5 ± 1.2 mUr (n = 30) and −50.31 ± 0.16 mUr (n = 14), respectively. For HUBG2 we obtained −102.0 ± 1.3 mUr (n = 32) and +1.60 ± 0.12 mUr (n = 16). Furthermore, the values obtained by GC/IRMS were in good agreement with the HTC‐ and EA‐IRMS values. Conclusions We suggest that both methyl sulfates are suitable reference materials for normalisation of isotope measurements of carbon of plant methoxy groups to isotope–δ scales and for inter‐laboratory calibration. For stable hydrogen isotope measurements, we suggest that in addition to HUBG1 and HUBG2 additional reference materials are required to cover the full range of plant methoxy groups reported so far.

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“…The general trend was to move towards carbon‐based reactors, but as far as halogenated compounds have been concerned, this option could not be retained in the case of salts . Thus, we used a modified Cr‐based reactor to optimize 2 H/ 1 H measurements of aqueous inclusions trapped in halite.…”

Section: Introductionmentioning

confidence: 99%

“…[18][19][20][23][24][25][26][27] The general trend was to move towards carbon-based reactors, but as far as halogenated compounds have been concerned, this option could not be retained in the case of salts. 13,14 Thus, we used a modified Cr-based reactor to optimize 2 H/ 1 H measurements of aqueous inclusions trapped in halite. In order to evaluate our technique, we generated "synthetic" halite crystals precipitated from a water reservoir where the 2 H/ 1 H ratio was monitored throughout the course of its evaporation from the initial stage until complete crystallization.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, for all the experiments, we observed a problem of clogging in the reaction tube after less than 100 sample runs, which is not desirable for that type of measurements. According to the suggestion of Gehre et al,14 we selected coarser (1-3 mm) chromium grains (Chempur chromium granules 1-3 mm 99+% part number 009543).This option partly solved the problem of clogging the tube by approximately doubling the number of sample runs before requiring repacking the reaction tube. To fully solve the clogging problem, we mixed the coarser-grained chromium with glassy carbon chips (Elementar carbon splintered 50 mL part number 11.64-0050) in an 80-20 proportion.…”

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Improved online hydrogen isotope analysis of halite aqueous inclusions

et al. 2019

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We demonstrate an improved method based on continuous‐flow elemental analyser pyrolysis isotopic ratio mass spectrometry (CF‐EA‐PY‐IRMS) to measure the 2H/1H ratios of water trapped in halite crystals. Two challenges to overcome are the low hydrogen concentration of samples (10‐50 μmol H2·g−1) and the high chloride concentration released when reacting halite in an elemental analyser. We describe an optimization procedure for determining the 2H/1H ratio of this trapped water with an acceptable accuracy. This technique involves the use of a high‐temperature Cr reactor to quantitatively convert H2O into H2. The initial step was performed on halite crystals precipitated from a water reservoir where 2H/1H ratios were monitored from its initial stage until the end of evaporation. The 2H/1H isotopic analyses were automated online in continuous‐flow mode. Precision of the method was determined for those “synthetic” samples with hydrogen concentrations ranging from 0.2 to 0.5 wt%. 2H/1H isotopic ratios of evaporating waters bracket the compositions of water inclusions. The formation of fluid inclusions is not instantaneous and records the isotopic signature of the residual waters across a time range during which the isotopic values of the water still evolve. This property explains why the δ2HVSMOW standard deviation of ±5‰ (2σ) observed for 10‐mg aliquots of halite exceeds the instrumental error (about ±1.5‰ 2σ) determined on the basis of IAEA‐CH7, NBS 30, and NBS 22 references along with calibrated waters with and without added halite crystals. We also applied this method to Mesoproterozoic (1.4 Ga) and Neoproterozoic (0.8 Ga) halite samples with relatively low hydrogen concentrations (300‐1500 ppm). The measured δ2HVSMOW values for Precambrian waters range from −89‰ to −54‰. We propose that this technique offers a new perspective and great potential for palaeoenvironmental reconstructions based on the 2H/1H analyses of water trapped in halite.

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Optimization of on‐line hydrogen stable isotope ratio measurements of halogen‐ and sulfur‐bearing organic compounds using elemental analyzer–chromium/high‐temperature conversion isotope ratio mass spectrometry (EA‐Cr/HTC‐IRMS)

Cited by 33 publications

References 26 publications

The interconversion of δ²H values of collagen between thermal conversion reactor configurations

The interconversion of δ²H values of collagen between thermal conversion reactor configurations

Methyl sulfates as methoxy isotopic reference materials for δ¹³C and δ²H measurements

Improved online hydrogen isotope analysis of halite aqueous inclusions

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Optimization of on‐line hydrogen stable isotope ratio measurements of halogen‐ and sulfur‐bearing organic compounds using elemental analyzer–chromium/high‐temperature conversion isotope ratio mass spectrometry (EA‐Cr/HTC‐IRMS)

Cited by 33 publications

References 26 publications

The interconversion of δ2H values of collagen between thermal conversion reactor configurations

The interconversion of δ2H values of collagen between thermal conversion reactor configurations

Methyl sulfates as methoxy isotopic reference materials for δ13C and δ2H measurements

Improved online hydrogen isotope analysis of halite aqueous inclusions

Contact Info

Product

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The interconversion of δ²H values of collagen between thermal conversion reactor configurations

The interconversion of δ²H values of collagen between thermal conversion reactor configurations

Methyl sulfates as methoxy isotopic reference materials for δ¹³C and δ²H measurements