Referencing strategies and techniques in stable isotope ratio analysis

Werner, Roland A.; Brand, Willi A.

doi:10.1002/rcm.258

Cited by 890 publications

(849 citation statements)

References 39 publications

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“…First, multiple standards whose isotopic compositions are known with the highest possible accuracy should be introduced at times that bracket analytes as closely as possible. Second, standards and samples should be handled as similarly as possible (the Identical Treatment Principle; [75]) to minimize the impact of isotopic fractionations due to injection, chromatography, chemical conversion, gas transfer, etc. The two goals are generally incompatible with a single strategy for standardization.…”

Section: Standardizationmentioning

confidence: 99%

Isotope‐ratio detection for gas chromatography

Sessions¹

2006

J of Separation Science

244

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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Section: Standardizationmentioning

confidence: 99%

Isotope‐ratio detection for gas chromatography

Sessions¹

2006

J of Separation Science

244

270

View full text Add to dashboard Cite

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“…[21] Isotope ratio mass spectrometry (IRMS) showed significant enrichment of 15 N in the synthesized (NH 4 ) 2 SO 4 . [22][23][24] An enrichment of up to 61 % over the natural 15 N/ 14 N isotope ratio was detected. This result exceeds by a factor of 10 any possible enrichment from variation in the natural 15 N/ 14 N isotope distribution.…”

mentioning

confidence: 97%

A Possible Prebiotic Formation of Ammonia from Dinitrogen on Iron Sulfide Surfaces

Dörr¹,

Käßbohrer²,

Grünert³

et al. 2003

Angew Chem Int Ed

Self Cite

126

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“…A sequence with all runs (Table 1) takes 140 min. The routine protocol involving an ice sample is as follows: (1) working standard "Boulder" through the bypass, (2) working standard "Saphir" over ice, (3) blank over ice, (4) ice sample, treating all measurements almost identically (Werner and Brand, 2001). Measuring "over ice" means that "Saphir" is injected via the SGE valve into the vessel and pumped towards the AirTrap, while the ice sample sits in the cold vessel at −5 • C throughout the procedure.…”

Section: Measurement Schemementioning

confidence: 99%

“…2.3.1) in the case of δ 13 C-CH 4 and pure N 2 O for δ 15 N-N 2 O and δ 18 O-N 2 O, both introduced as rectangular on/off peaks. To report our values on an international scale against a reference processed following the identical treatment principle (Werner and Brand, 2001), we use our "Boulder" measurements, which are processed on a daily basis. Similar to the calculation of the mixing ratios, the long-term evolution of the δ 13 C-CH 4 , δ 15 N-N 2 O and δ 18 O-N 2 O of the "Boulder" measurements are used to reference the samples and to eliminate the stochastic measurement uncertainty in the daily values (see Fig.…”

Section: Long-term Trends and Referencing To International Standardsmentioning

confidence: 99%

Online technique for isotope and mixing ratios of CH<sub>4</sub>, N<sub>2</sub>O, Xe and mixing ratios of organic trace gases on a single ice core sample

et al. 2014

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Abstract. Firn and polar ice cores enclosing trace gas species offer a unique archive to study changes in the past atmosphere and in terrestrial/marine source regions. Here we present a new online technique for ice core and air samples to measure a suite of isotope ratios and mixing ratios of trace gas species on a single sample. Isotope ratios are determined on methane, nitrous oxide and xenon with reproducibilities for ice core samples of 0.15 ‰ for δ 13 C-CH 4 , 0.22 ‰ for δ 15 N-N 2 O, 0.34 ‰ for δ 18 O-N 2 O, and 0.05 ‰ per mass difference for δ 136 Xe for typical concentrations of glacial ice. Mixing ratios are determined on methane, nitrous oxide, xenon, ethane, propane, methyl chloride and dichlorodifluoromethane with reproducibilities of 7 ppb for CH 4 , 3 ppb for N 2 O, 70 ppt for C 2 H 6 , 70 ppt for C 3 H 8 , 20 ppt for CH 3 Cl, and 2 ppt for CCl 2 F 2 . However, the blank contribution for C 2 H 6 and C 3 H 8 is large in view of the measured values for Antarctic ice samples. The system consists of a vacuum extraction device, a preconcentration unit and a gas chromatograph coupled to an isotope ratio mass spectrometer. CH 4 is combusted to CO 2 prior to detection while we bypass the oven for all other species. The highly automated system uses only ∼ 160 g of ice, equivalent to ∼ 16 mL air, which is less than previous methods. The measurement of this large suite of parameters on a single ice sample is new and key to understanding phase relationships of parameters which are usually not measured together. A multi-parameter data set is also key to understand in situ production processes of organic species in the ice, a critical issue observed in many organic trace gases. Novel is the determination of xenon isotope ratios using doubly charged Xe ions. The attained precision for δ 136 Xe is suitable to correct the isotopic ratios and mixing ratios for gravitational firn diffusion effects, with the benefit that this information is derived from the same sample. Lastly, anomalies in the Xe mixing ratio, δXe/air, can be used to detect melt layers.

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Referencing strategies and techniques in stable isotope ratio analysis

Cited by 890 publications

References 39 publications

Isotope‐ratio detection for gas chromatography

Isotope‐ratio detection for gas chromatography

A Possible Prebiotic Formation of Ammonia from Dinitrogen on Iron Sulfide Surfaces

Online technique for isotope and mixing ratios of CH<sub>4</sub>, N<sub>2</sub>O, Xe and mixing ratios of organic trace gases on a single ice core sample

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Referencing strategies and techniques in stable isotope ratio analysis

Cited by 890 publications

References 39 publications

Isotope‐ratio detection for gas chromatography

Isotope‐ratio detection for gas chromatography

A Possible Prebiotic Formation of Ammonia from Dinitrogen on Iron Sulfide Surfaces

Online technique for isotope and mixing ratios of CH&lt;sub&gt;4&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O, Xe and mixing ratios of organic trace gases on a single ice core sample

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Online technique for isotope and mixing ratios of CH<sub>4</sub>, N<sub>2</sub>O, Xe and mixing ratios of organic trace gases on a single ice core sample