Show simple item record Topalov, Katarina Schimmelmann, Arndt Polly, David Sauer, Peter E. 2009-02-02T18:46:02Z 2009-02-02T18:46:02Z 2008-04-07
dc.description.abstract The organic hydrogen isotope ratio (deuterium/hydrogen or D/H) in the tissues of terrestrial organisms is related to D/H values of precursor hydrogen in diet and water from precipitation. D/H in (fossil) bone collagen potentially characterizes the (paleo)environment of an animal. However, the original (paleo)environmental isotopic signal of organic hydrogen is largely limited to carbon-linked hydrogen (C-H). In contrast, organic hydrogen that is chemically linked to other elements (e.g., oxygen O-H and nitrogen N-H) is more loosely bound and exchanges with ambient water, even during storage and sample preparation. Further, the fraction of exchangeable hydrogen in total hydrogen can vary among samples. The uncertainty from exchangeable hydrogen can be reduced via equilibration with isotopically known water vapors and subsequent mass-balance calculations arriving at the D/H of non-exchangeable hydrogen in collagen. Labor-intensive methods for isotopic equilibration of exchangeable organic hydrogen with water vapor have been used for more than 15 years. Here we present data from steam-equilibrated samples using a more efficient continuous-flow (i.e., on-line) approach using a ThermoFinnigan TC/EA fitted with an autosampler. Collagens from bones of modern White tail deer (Odocoileus virginianus) and Southern mule deer (O. hemionus) across climate gradients in the USA were prepared for our preliminary study. Traditionally, TC/EA samples are wrapped tightly in non-permeable silver capsules that limit the access of steam to collagen. Our samples were loaded into individual micro-perforated silver TC/EA cups. Cups were crimped shut and looked like small shopping bags. The perforations at the bottom of each cup were small enough that collagen could not spill out of the cup, but steam and gas could freely pass into and out of the cups. Steam equilibration of an entire carousel (up to 49 cups) in an equilibration chamber occurred overnight with isotopically known steam at 115ºC, followed by drying with dry nitrogen, cooling, rapid transfer of the carousel to the TC/EA, and determination of D/H. We present preliminary results from collagens and discuss advantages of the new method. en
dc.format.extent 1833472 bytes
dc.format.mimetype application/
dc.language.iso en_US en
dc.publisher Isoscapes 2008 Conference en
dc.rights This work is licensed under the Creative Commons Attribution-NonCommercial 3.0 Unported License. To view a copy of this license, visit or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA. en
dc.rights.uri en
dc.subject stable isotopes en
dc.subject hydrogen en
dc.subject paleoclimate en
dc.subject paleoenvironment en
dc.subject collagen en
dc.subject on-line continuous-flow en
dc.title Improved On-line Measurement of Bone Collagen D/H as Forensic Environmental Indicator en
dc.type Presentation en

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