Impact of contamination and pre-treatment on stable carbon and nitrogen isotopic composition of charred plant remains.
Bottom Line: Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis.The results show a ca 1‰ decrease in the δ(15)N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication.This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre-treat their samples with methods that have been demonstrated to be effective.
Affiliation: Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.Show MeSH
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Mentions: Nitrate contamination causes progressively lower δ15N values with increasing percent contamination (5.5‰, 4.4‰, 1.3‰), but is only detectable using FTIR when the contamination is 10% or higher (peaks at 1085, 1450, 3300 cm–1) (see Fig.5). After treatment with water, all samples become indistinguishable from the uncontaminated and 5% contaminated sample, suggesting that no more than 5% of nitrates remain in the samples after pre-treatment.
Affiliation: Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.