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This resulted in lower collagen yields for the poorly preserved bones and in the case of R-EVA 548, the yield of these extracts was so low that the extracts were affected by C contamination to a large extent.
During the gelatinisation stage (step 3), the collagen yield was higher from aliquots which were removed from the heater block as soon as solubilisation had occurred compared to those left on the heater block for 20 h as per our standard protocol for C dating (Supplementary Dataset S1).
Different labs vary in the strength of reagents used, the duration of treatments and the inclusion of further decontamination steps.
Many studies have been published comparing the collagen yields and isotopic values of the various extraction protocols published in the literature.
Each collagen extract was split and dated multiple times with the gas ion source of the Aix MICADAS to test replicability. 90 μg C to explore the effect of sample size on the blank level of the EA-GIS-AMS system.
The gas dates were compared with graphite dates from collagen extracted from 500 mg material of the same bones. The results demonstrate our ability to obtain accurate and moderately precise radiocarbon dates from N) and were measured at the Klaus-Tschira-AMS lab in Mannheim, Germany (lab code: MAMS). Step 3: duration and temperature of the gelatinisation stage (HCl p H3).
A higher number of data points are present for R-EVA 1753 (e) as an aliquot of this bone was extracted alongside each batch of samples.
The horizontal grey band in e shows the range in collagen yield of repeated large extractions from the background bone.
The dashed lines at 1% show the guideline minimum requirement for reliable The standard practice in our lab is to extract large bone aliquots (ca. Although this method requires a large time investment (demineralisation can take up to four weeks with the HCl 0.5 M changed twice per week), we observe much higher collagen yields using this technique compared to powdered extracts of equal starting weight.
However, many precious archaeological bones, such as human remains or Palaeolithic bone tools, are too small or valuable for extensive destructive sampling.
The results reported here demonstrate that we are able to reproduce accurate radiocarbon dates from Bone is one of the most frequently radiocarbon-dated materials recovered from archaeological sites.
In recent years, several AMS labs have worked on modifications to the graphitisation and AMS measurement process for smaller samples containing .