Different pretreatment methods for 14C dating of Younger Dryas and Allerod pine wood (Pines sylvestris L.)

An analysis was performed on samples from a series of well-preserved tree trunks and in situ stumps of Allerod/ Younger Dryas age found in Kozmin and Kwiatkow, Kolska Basin, Central Poland. Five different types of wood preparation methods were investigated in three Polish radiocarbon laboratories (Gliwice, Poznan and Krakow) in order to find the most stable, repeatable and reliable procedure. Their effect was tested on the stable carbon isotope ratio (delta C-13) and C-14 age. Additionally, FTIR spectroscopy was used as a simple technique for obtaining rapid information on the structure of wood constituents and chemical changes taking place in wood due to various chemical treatments. The results of AMS measurements did not show statistically significant differences in radiocarbon ages of samples prepared according to the tested methods. On the other hand, delta C-1(3) measurements showed that the smallest scattering results gave a-cellulose obtained by the method BABA + Bleaching (with NaClO2 and HCl) + strong base. Moreover, the mean delta C-13 values for holo-cellulose samples are higher than those for alpha-cellulose samples. Studies evidenced that the methods of preparation leading to holo- or alpha-cellulose gave the same FTIR spectra, while the standard method of the chemical pretreatment of samples for C-14 measurements (ABA) preceded by mercerization is insufficient for removing compounds containing aromatic rings.