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  • IRMS
  • HPLC
  • Carbon isotopes
  • Pharmaceuticals

irm-LC/MS: ?13C of Analgesic and Antipyretic Drugs

Andreas W. Hilkert, Michael Krummen, Dieter Juchelka

Thermo Fisher Scientific, Bremen, Germany

AN30025

Goal: Isotope ratio monitoring-LC/MS (irm-LC/MS) with the Thermo Scientific LC IsoLink helps to determine the sources of pharmaceuticals via the individual 13C/12C ratio (?13C values) of the ingredients. Small amounts in complex mixtures can be applied for compound specific isotope analysis without extensive preparation or derivatization.

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  • IRMS
  • Triple Oxygen Isotopes
  • Diatoms

A calibration of the triple oxygen isotope fractionation in the SiO2–H2O system and applications to natural samples

Z.D. Sharp (1,2), J.A. Gibbons (1), O. Maltsev (1), V. Atudorei (1,2), A. Pack (3), S. Sengupt (1,3), E.L. Shock (4,5) and L.P. Knauth (4)

1) Department of Earth and Planetary Sciences, University of New Mexico, 200 Yale Blvd, Albuquerque, NM 87131, USA, 2) Center for Stable Isotopes, University of New Mexico, 200 Yale Blvd, Albuquerque, NM 87131, USA, 3) Geowissenschaftliches Zentrum, Georg-August-Universität, Goldschmidtstraße 1, D-37073 Göttingen, Germany, 4) School of Earth and Space Exploration, Arizona State University, PO Box 871404, Tempe, AZ 85287-1404, USA, 5) School of Molecular Sciences, Arizona State University, PO Box 871404, Tempe, AZ 85287-1404, USA

Geochimica et Cosmochimica Acta (2016), V186, pp105–119, doi:10.1016/j.gca.2016.04.047

Goal: It is now recognized that variations in the ?17O of terrestrial materials resulting from purely mass dependent fractionations, though small, have geological significance. In this study, the ?18O and ?17O values of selected low temperature quartz and silica samples were measured in order to derive the quartz-water fractionation–temperature relationship for the three oxygen isotope system. A 18O/16O quartz-water fractionation equation valid for all temperatures was generated from published high temperature exchange experiments and ...

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  • IRMS
  • CO2
  • DOC
  • Oxygen Isotopes

An “On-Line” Method for Oxygen Isotope Exchange Between Gas-Phase CO2 and Water

N.P. Levitt (1,2) and C.S. Romanek (3)

1) NASA Astrobiology Institute and Department of Earth and Environmental Sciences, University of Kentucky, USA, 2) NASA Astrobiology Institute and Department of Geoscience, University of Wisconsin-Madison, USA, 3) NASA Astrobiology Institute and Department of Earth and Environmental Sciences, Furman University, USA

Aquatic Geochemistry (2016), V22 (3), pp 253-269, doi: 10.?1007/?s10498-016-9291-5

Goal: An “on-line” mixing system has been developed and evaluated for continuous oxygen isotope exchange between gas-phase CO2 and liquid water. The system is composed of three basic parts: equipment and materials used to introduce water and gas into a mixing reservoir, the mixing and exchange reservoir, and a vessel used to separate gas and water phases exiting the system. A series of experiments were performed to monitor the isotope exchange process over a range of temperatures (5–40 °C) and CO2 partial pressures (202–15,200 Pa).

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  • IRMS
  • C isotopes
  • DOC
  • Methane cycling

Origin and temporal variability of unusually low ?13C-DOC values in two High Arctic catchments

R.S. Hindshaw (1), S.Q. Lang (2,3), S.M. Bernasconi (3), T.H.E. Heaton (4), M.R. Lindsay (5) and E.S. Boyd (5)

1) Department of Earth and Environmental Sciences, University of St. Andrews, St. Andrews, UK; 2) Department of Earth Sciences, ETH Zürich, Zurich, Switzerland, 3) Department of Earth and Ocean Sciences, University of South Carolina, Columbia, South Carolina, USA, 4) NERC Isotope Geosciences Laboratory, Nottingham, UK, 5) Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA

Journal of Geophyiscal Research (2016), V121, pp1073–1085, doi:10.1002/2015JG003303.

Goal: The stable carbon isotopic composition of dissolved organic matter (?13C-DOC) reveals information about its source and extent of biological processing. Here we report the lowest ?13C-DOC values (?43.8‰) measured to date in surface waters. The streams were located in the High Arctic, a region currently experiencing rapid changes in climate and carbon cycling. Based on the widespread occurrence of methane cycling in permafrost regions and the detection of the pmoA gene, a proxy for aerobic methanotrophs, we conclude that the low ?13C-DOC values are due to organic matter partially derived from methanotrophs consuming biologically produced, 13C-depleted methane. These findings demonstrate the significant impact that biological activity has on the stream water chemistry exported from permafrost and glaciated environments. ..., occurrences of low ?13C-DOC values may be more widespread than previously recognized, with implications for understanding C cycling in these environments.

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  • IRMS
  • Gas Bench II
  • Carbon Isotopes
  • Natural waters

Precise ?13C analysis of dissolved inorganic carbon in natural waters using automated headspace sampling and continuous-flow mass spectrometry.

M. E. Torres, A. C. Mix, and W. D. Rugh

College of Oceanic and Atmospheric Sciences, Oregon State University Corvallis, OR 97331-5503, USA

Limnology and Oceanography; Methods (2005), V3 (8), pp349–360, doi: 10.4319/lom.2005.3.349

Goal: A new method is presented for automated measurement of the ?13C of the dissolved inorganic carbon in natural waters, using a Gas Bench-II online with a DELTA XL IRMS. This technique requires a volume (30-500 mL), analyses are rapid (~80 samples/d), and little / no manual preparation is necessary. The flexibility offered by using sample loops of various sizes permits analyses of aliquots containing 2 to 50 ?g C. Based on multiple replicate measurements over a 7-week period, the precision of this technique is estimated to be better than ± 0.15‰ (1 sample std. dev.), which is similar to the precision of methods in use. This precision can be improved upon (averaging ± 0.04‰, but generally better than ± 0.07‰) and analyses are monitored against a stock solution of reagent NaHCO3, which remains isotopically stable in powder form. NaHCO3 can be analyzed with traditional acid-digestion methods using dual-inlet mass spectrometry, as well as in dissolved form on the Gas Bench-II.

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  • IRMS
  • Gas Bench II
  • Hydrogen Isotopes
  • Fruit Juice and Wine

Automated H2/H2O Equilibration for ?D Determination on Aqueous Samples Using Thermo Scientific Gas Bench II

Alexander Duhr, Andreas Hilkert

Thermo Fisher Scientific, Bremen, Germany

AN30049

Goal: The measurement of the D/H ratio of water is one of the most important pplications of isotope ratio massspectrometers. Very diverse applications, ranging from studies of variations in natural abundance in the hydrologic cycle to authenticity control of beverages or the use of D-enriched tracers in human and animal metabolic studies, demand a general analytical solution, which provides high precision/ high accuracy/high throughput analysis of D/H in an enormous range of aqueous substrates. With the Gas Bench II, water samples > 200 ?L can be routinely analyzed with a precision and accuracy < 1 ‰.

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  • IRMS
  • Gas Bench II
  • ?18O and ?13C
  • Carbonate materials
  • Small samples sizes

?18O and ?13C Determination of Carbonates

Alexander Duhr, Andreas Hilkert

Thermo Fisher Scientific, Bremen, Germany

AN30050

Goal: The Thermo Scientific Gas Bench II with the Carbonate-Option, an autosampler assisted sample preparation and loop injection interface, offers a fast and flexible alternative using modern continuous flow technology coupling to the ThermoScientific isotope ratio mass spectrometers DELTA V Advantage, DELTA V Plus and 253 Plus. The Gas Bench II in carbonate mode uses the principle of individual acid baths. Laboratories have shown that at least 80 samples per day (including 14 standards for quality control) can be processed in routine operation. An overall precision of 0.08 ‰ for ?18O and of 0.06 ‰ for ?13C or better has been achieved and accurate measurements of samples containing in excess of 100 ?g of carbonate.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • DOM

irm-LC/MS: ?13C Analysis of Dissolved Organic Matter in Natural Waters

Patrick Albéric (1), Pascale Gautret (1), Dieter Juchelka (2)

1) Institut des Sciences de la Terre d‘Orléans, CNRS/Université d‘Orléans, France; 2) Thermo Fisher Scientific, Bremen, Germany

AN30198

Goal: The isotopic composition of DOM and DOC can now be measured by the Thermo Scientific LC IsoLink, the on-line coupling of a liquid chromatograph with an isotope mass spectrometer. With the LC IsoLink™ interface, two approaches are possible: DOC ?13C can be measured either by direct flow injection of water samples (as well as of fractions isolated off-line from larger volumes of water) or, alternatively, for on-line separation of DOM fractions size exclusion chromatography (SEC) for instance can be applied.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • Organic acids

irm-LC/MS: ?13C Analysis of Organic Acids in Plants

Elena Hettmann (1), Gerd Gleixner (1), Dieter Juchelka (2)

1) Max Planck Institute for Biogeochemistry, Jena, Germany, 2) Thermo Fisher Scientific, Bremen, Germany

AN30075

Goal: The new Thermo Scientific LC IsoLink interface enables the on-line coupling of a liquid chromatograph to a stable isotope ratio mass spectrometer. It significantly reduces the preparation steps and the analysis time. We present an analytical method for the isotope ratio analysis of organic acids in different plants extracts. First results are reported and discussed.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • Amino acids

irm-LC/MS: ?13C Analysis of Underivatized Amino Acids

Dieter Juchelka, Michael Krummen

Thermo Fisher Scientific, Bremen, Germany

AN30065

Goal: Isotope ratio monitoring-LC/MS (irm-LC/MS) with the Thermo Scientific LC IsoLink allows determination of 13C/12C ratios of individual amino acids without derivatization, eliminating all of the possible errors, limitations, and time requirements of derivatization. For amino acids water is the best solvent; HPLC columns are available on which the separation of amino acids can be performed with an aqueous mobile phase. The LC IsoLink offers new access to 13C-tracer experiments which investigate amino acid and protein metabolism.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • RNA

irm-LC/MS: ?13C Analysis of RNA

Barbara J. MacGregor (1), Adam Friedman (1), Dieter Juchelka (2)

1) Department of Marine Sciences, University of North Carolina, Chapel Hill, N.C. USA; 2) Thermo Fisher Scientific, Bremen, Germany

AN30055

Goal: With the development of the Thermo Scientific LC IsoLink interface, compounds can now be separated by HPLC and analyzed online for their individual 13C/12C ratios by isotope ratio MS. Here we report progress towards a method for HPLC separation of hydrolyzed RNA and determination of the carbon isotopic composition of the monomers.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • DOC

Rapid and precise ?13C measurement of dissolved inorganic carbon in natural waters using liquid chromatography coupled to an isotope-ratio mass spectrometer

Jay A. Brandes

Skidaway Institute of Oceanography, Savannah, GA, USA

Limnology and Oceanography: Methods (2009), V7 (11), doi: 10.4319/lom.2009.7.730

Goal: The measurement of the carbon isotopic composition (delta13C) of dissolved inorganic carbon (DIC) in natural systems has provided a tool for examining a variety of processes, from net primary production to anthropogenic signatures of CO2 uptake in the oceans. Over the past decade, new delta13C-DIC methods have steadily decreased the sample analysis time and volumes for this measurement. The development of a new interface capable of inline acidification and extraction of CO2 from a liquid stream (LC-Isolink™) provides breakthroughs in sample size, ease of sample handling, and speed of analyses. Typical sample size injections of 25 microL provide precision and accuracy of 0.04‰, comparable to that obtained by off-line extractions/dual inlet analyses on much larger samples.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • Methanol

Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography–isotope ratio mass spectrometry

Keiko Tagami, Shigeo Uchida

National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan

Analytica Chimica Acta (2008), V614(2), pp165–172, doi: 10.1016/j.aca.2008.03.041

Goal: A suitable analysis condition was determined for high performance liquid chromatography–isotope ratio mass spectrometry (HPLC–IRMS) while making sequential measurements of stable carbon isotope ratios of d13C in formic acid, acetic acid, methanol and ethanol dissolved in water.

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  • IRMS
  • HPLC
  • Carbon isotopes
  • Fatty acids

Online ?13C analysis of volatile fatty acids in sediment/porewater systems by liquid chromatography-isotope ratio mass spectrometry

Verena Heuer, Marcus Elvert, Stefanie Tille, Michael Krummen, Xavier Prieto Mollar, Laura R. Hmelo, Kai-Uwe Hinrichs

1) Organic Geochemistry Group, DFG-Research Center Ocean Margins & Dept. of Geosciences, University of Bremen, P.O. Box 330 440, D-28334 Bremen, Germany, 2) Thermo Electron Corporation, Finnigan Advanced Mass Spectrometry, Hanna-Kunath-Strasse 11, D-28199 Bremen, Germany

Limnology and Oceanography: Methods (2006), V4, pp346–357, doi: 10.4319/lom.2006.4.346

Goal: Volatile fatty acids (VFAs) are central intermediates of anaerobic metabolism and present in aquatic environments such as marine sediments. Conceptually, the isotopic composition of volatile fatty acids is presumed to be sensitive to the specific biogeochemical processes involved in their production and consumption. However, due to generally low environmental concentrations, our knowledge on isotopic variability of VFAs is limited. We report the development and application of a new protocol for compound-specific carbon isotopic analysis of VFAs in marine porewaters and other aqueous liquids. This new protocol involves reversed-phase separation of volatile fatty acids with an aqueous mobile phase by high performance liquid chromatography (HPLC) combined with chemical oxidation of the effluents by the FinniganTM LC IsoLink interface (Krummen et al. 2004) and subsequent online transfer of the resulting CO2 into an isotope ratio mass spectrometer.

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  • GC-IRMS
  • Gas Chromatography
  • Fatty Acid Methyl Esters

irm-GC/MS: ?13C in Fatty Acid Methyl Esters (FAME)

Andreas W. Hilkert (1), Dieter Juchelka (1) and Charles B. Douthitt (2)

1) Thermo Fisher Scientific, Bremen, Germany, 2) Thermo Fisher Scientific, Arizona, USA

AN30052

Goal: Isotope Ratio Monitoring GC/MS (irm-GC/MS) measurement of the delta13C content of the methyl esters of fatty acids (FAME) has been used to study natural food webs and, with the use of highly delta13C –enriched precursors, fatty acid metabolism in vivo. The use of biolabeled fatty acids to study metabolism is a relatively new technique which combines tracer methodology with natural abundance measurements by using naturally labeled compounds as tracers.