The interconversion of δ H values of collagen between thermal conversion reactor configurations.

Rapid Commun Mass Spectrom 2019 Apr;33(7):678-682

Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA, 02138, USA.

Rationale: Different thermal conversion reactor packings result in distinct δ H values in nitrogen-containing materials, such as bone collagen. An older 'traditional' glassy carbon packing method causes incomplete conversion of N-containing samples into H gas, resulting in altered δ H values compared with the complete conversion of hydrogen obtained with a chromium-packed reactor. Given that δ H values from collagen are gaining importance in palaeoecological and archaeological studies, a determination of the relationship between δ H values produced with a glassy-carbon-packed and a chromium-packed reactor is needed.

Methods: We obtained δ H 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: δ H values from both methods are linearly correlated (r  = 0.934) and yield the following interconversion equation, δ H(Cr) = 1.054 δ H(GP) + 11.6‰ (95% conf. slope 1.020-1.090, intercept 10.6-12.6), and a mean difference of δ H(Cr) - δ H(GP) = 10.1‰ (1 sd 5.2, 1 se 0.3, n = 231).

Conclusions: We recommend adopting this interconversion between δ H values produced with a glassy-carbon-packed and chromium-packed reactor for bone collagen only, with appropriate propagation of uncertainty.

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http://dx.doi.org/10.1002/rcm.8396DOI Listing
April 2019
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References

(Supplied by CrossRef)
Hydrogen isotopes in quaternary mammal collagen from Europe
Gröcke et al.
J Archaeol Sci Rep 2017
Oxygen and hydrogen isotopes in rodent tissues: Impact of diet, water and ontogeny
Kirsanow et al.
Palaeogeogr Palaeoclimatol Palaeoecol 2011

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