A UNIVERSAL GAS INTERFACE FOR SIMULTANEOUS 14C AND δ13C MEASUREMENTS

While simultaneous radiocarbon and delta C-13 measurements have been available for organic materials (by accelerator mass spectrometry, AMS, and isotope ratio mass spectrometry, IRMS, respectively), this has not been possible for carbonates until now. Using an existing interface for gas ion source AMS measurements, we developed a prototype for a universal gas interface that allows simultaneous measurement of both carbon isotope ratios from potentially any source of CO2. First results obtained from reference materials (IAEA-C6, OxaII, PhA, IAEA-C1, IAEA-C2, ETH-4) show that for both organic as well as carbonate samples, the precision of radiocarbon measurements in the coupled mode is comparable to routine standalone AMS measurements. For IRMS delta C-13 measurements, the performance for different materials shows more variation with precisions ranging from 0.07 parts per thousand to 0.47 parts per thousand. However, both organic materials and carbonates can achieve precisions as good as 0.13 parts per thousand. Once fully automated, the method shows potential for filling the gap of simultaneous carbon isotope measurements for non-organic materials.