T01_06

Simultaneous ¹⁴C and ¹³C measurements for any source of CO²

Wertnik M¹,  Wacker L¹, Haghipour N¹, Bernasconi S¹, Synal H¹, Eglinton T¹, Welte C¹

¹ETH Zurich, Zürich, Switzerland

Carbon isotopes are an important source of information for a broad range of research fields related to carbon cycle studies and beyond. In this context, radiocarbon can be used to study temporal and partitioning effects, while the stable isotope (¹³C) gives information about the source of the carbon (e.g. terrestrial or marine). Recently, an approach enabling the simultaneous analysis of all naturally occurring carbon isotopes in organic combustible materials has been introduced[1].

Here, we present a novel and very flexible method for simultaneous ¹⁴C and ¹³C measurements that can be combined with any CO₂-feeding interface. The CO₂ from the sample is captured on a zeolite trap and subsequently transferred into a syringe, where it is diluted with Helium to a concentration of around 4%. The syringe allows constant feeding of the gas for simultaneous measurement with a split of 85% of gas to the accelerator mass spectrometer (AMS) and 15% to the isotope ratio mass spectrometer (IRMS). For carbonate samples, we can measure samples from 8 – 200 μg of Carbon to a precision of 0.1‰.

[1]          C. P. McIntyre et al., ‘Online ¹³C and ¹⁴C Gas Measurements by EA-IRMS-AMS at ETH Zürich’, Radiocarbon, vol. 59, no. 3, pp. 893–903, Oct. 2016