Sequential measurement of δ15N, δ13C and δ34S values in archaeological bone collagen at the Scottish Universities Environmental Research Centre (SUERC): a new analytical frontier

Sayle, K. L. , Brodie, C. R., Cook, G. T. and Hamilton, W. D. (2019) Sequential measurement of δ15N, δ13C and δ34S values in archaeological bone collagen at the Scottish Universities Environmental Research Centre (SUERC): a new analytical frontier. Rapid Communications in Mass Spectrometry, 33(15), pp. 1258-1266. (doi: 10.1002/rcm.8462) (PMID:30993809)

Abstract

Rationale: The use of multi‐isotopic analysis (δ15N, δ13C and δ34S values) of archaeological bone collagen to assist in the interpretation of diet, movement and mobility of prehistoric populations is gradually increasing, yet many researchers have traditionally avoided investigating sulphur due to its very low concentrations (<0.3%) in mammalian collagen. For this reason, and as a consequence of analytical detection limits, sulphur is usually measured separately from carbon and nitrogen, which leads to longer analytical times and higher costs. Methods: A Thermo ScientificTM EA IsoLinkTM IRMS system, with the ability to rapidly heat a gas‐chromatography (GC) column and concentrate the sample gas online without cryo‐trapping, was used at the Radiocarbon Laboratory at SUERC. Optimisation of the GC temperature and carrier gas flow rate in the elemental analyser resulted in improved signal‐to‐noise ratio and sensitivity for SO2. This allowed for routine sequential N2, CO2 and SO2 measurements on small samples of bone collagen. Results: Improvements in sample gas transfer to the mass spectrometer allows for sequential δ15N, δ13C and δ34S values to be measured in 1–1.5 mg samples of bone collagen. Moreover, the sensitivity and signal‐to‐noise ratio of the sample gas, especially SO2, is improved, resulting in precisions of ±0.15‰ for δ15N values, ±0.1‰ for δ13C values and ±0.3‰ for δ34S values. Previous instrumentation allowed for the analysis of ~30 unknown samples before undertaking maintenance; however, ~150 unknown samples can now be measured, meaning a 5‐fold increase in sample throughput. Conclusions: The ability to sequentially measure δ15N, δ13C and δ34S values rapidly in archaeological bone collagen is an attractive option to researchers who want to build larger, more succinct datasets for their sites of interest, at a much‐reduced analytical cost and without destroying larger quantities of archaeological material.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sayle, Dr Kerry and Hamilton, Professor Derek and Cook, Professor Gordon
• Authors: Sayle, K. L., Brodie, C. R., Cook, G. T., and Hamilton, W. D.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Rapid Communications in Mass Spectrometry
• Publisher: Wiley
• ISSN: 0951-4198
• ISSN (Online): 1097-0231
• Published Online: 16 April 2019
• Copyright Holders: Copyright © 2019 John Wiley & Sons, Ltd
• First Published: First published in Rapid Communications in Mass Spectrometry 33(15):1258-1266
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher