Postdoc in Characterization and 14C dating of ultra-small bone collagen samples

Radiocarbon (14C) dating is one of the most accurate dating methods for the past 50,000 years, and certainly the most accurate for the Holocene. Limiting the amount of sample needed for 14C dating is crucial for archaeologists and conservators, and constant efforts have been made in this area. The new generation of accelerators (Compact Radiocarbon System, or CRS), paves the way for dating small quantities of bone samples, in the order of 100 mg of bone or less. The main challenge in employing micro-samples is the increase in the risk of contamination and thus efficient sample preparation protocols need to be developed. The reliable application of these protocols to micro-samples thus requires a biochemical (and/or chemical) characterization of the collagen extracted. New developments in mass spectrometry enable efficient analysis of the bone proteins and it is now possible to confirm the purity of the collagen samples and also to characterize the presence of organic contaminants and/or micro-organisms. This project aims to evaluate the following points: (1) collagen from very small bone samples can be efficiently extracted and chemically characterized, (2) soil pollution (humic acids, fungi) can be identified and eliminated, (3) reliable 14C ages can be measured on these very small samples.

The post-doc will be responsible for sample analysis in the laboratory and for the interpretation of results. He/she will test several collagen extraction protocols, and choose the best suited to the dating of micro-samples depending on the biochemical characterization of the organic residues by mass spectrometry (MALDI, Py-GC-MS, LC-MS) with different partners. He/she will be responsible for the preparation of the micro-samples for 14C dating on the collagen extraction line and subsequent measurement using CRS located in Gif–sur-Yvette (Ile de-France) which would be accessible from 2015. The validated analytical protocol will be implemented in collaboration with collaborators from bioarchaeology to several projects for which dating using small quantity of samples is crucial (e.g., micro- vertebrates, human remains or artifacts of high cultural heritage value).

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Contact Antoine Zazzo