A support for geochronological studies—a new 14C sample treatment laboratory at the Maria Curie-Sklodowska University, Lublin, PL

Radiocarbon dating is an essential tool in paleo and environmental studies. The selection of a suitable sample and its preparation for radiocarbon dating are key steps that affect the accuracy and precision of the results. Proper preparation allows the elimination of impurities that, by distorting the carbon isotope ratio, could lead to errors in determining the sample's actual age. Different purification procedures and modifications are applied depending on the type of sample being subjected to radiocarbon dating. Each material type requires an individual approach, considering its properties, state of preservation, and potential sources of contamination. Close collaboration among researchers in the application fields of ¹⁴C (archaeologists and earth scientists) is vital from the first step of sample selection. University-based ¹⁴C preparation laboratories focusing on selecting and treating suitable ¹⁴C material can facilitate such interdisciplinary exchange. Moreover, ¹⁴C laboratories located at universities can help educate the next generation of geochronologists.

In the past 2 years, a new preparation laboratory has been established at Maria Curie-Skłodowska University (UMCS) in the Ecotech-Complex in Lublin. The first sediment samples, peat, wood, and charcoal, were separated and successfully analysed at the ETH AMS facility in Zurich. Our laboratory is equipped to prepare all macroscopic samples and follows the sample selection procedures described by Hajdas et al. (2024).

Selected, well-defined samples undergo standard chemical treatment. The primary purification procedure for organic samples is the ABA (Acid-Base-Acid) procedure. It involves successive acid and base treatments at elevated temperatures to remove carbonates and humic substances, followed by a final acid treatment to neutralize the sample. The basic procedure is often modified to the specific sample being analyzed, for example, by lowering temperatures and reducing contact time for samples with poorly preserved structures. At this stage, treating the sample with alkali also enables the separation of humic acids, which can then be analyzed for ¹⁴C.

The clean, dry samples are weighed (approximately 1 mg of C) and transferred to the AMS laboratory. At this point, if the clean samples are very small, an additional material sample can be prepared, or samples containing less than 100 μg of carbon can be measured using a Gas Ion Source (GIS) (Ruff et al., 2010). Secondary standards and blanks are prepared alongside the ‘unknown’ samples. This paper reports the first results obtained from samples prepared in the LBC14 laboratory.

References

Hajdas, I., Guidobaldi, G., Haghipour, N., and Wyss, K. 2024. Sample Selection, Characterization and Choice of Treatment for Accurate Radiocarbon Analysis—Insights from the ETH Laboratory. Radiocarbon 66(5):1152-1165. doi:10.1017/RDC.2024.12

Ruff, M., Fahrni, S., Gaggeler, H. W., Hajdas, I., Suter, M., Synal, H. A., Szidat, S., and Wacker, L., 2010, On-Line Radiocarbon Measurements of Small Samples Using Elemental Analyzer and Micadas Gas Ion Source: Radiocarbon, v. 52, no. 4, p. 1645-1656.