Retreatment of bone material in the gliwice radiocarbon laboratory using ultrafiltration

Preparation of bones for radiocarbon (C-14) dating is still quite a challenge for researchers. The methods are being tested and improved, to increase reliability of dating results and to verify the previous ones. In this work, a set of gelatine samples, extracted from Cervus elaphus and Cervus canadensis bones from various sites in Europe and a set of human bones from archaeological sites in Poland were subjected to retreatment using ultrafiltration in Gliwice Radiocarbon Laboratory. The tested samples represent a wide range of ages, from older than 40,000 C-14 years BP to modern. The prepared material was subjected to the measurement of C/N atomic ratios and C-14 dating using the accelerator mass spectrometry (AMS) technique. Also, the stable isotopes (delta C-13 and delta N-15) values were determined. In a few cases ultrafiltration allows to improve gelatine quality for long-stored samples, by increasing the %C and %N as well as decreasing C/N(at )ratios. Nevertheless, this effect was not observed for majority of the samples. Remeasurements of long-term stored samples give mostly the same C-14 ages for ultrafiltered ones and for those without ultrafiltration.