Carbon isotope fractionation between dissolved and gaseous carbon dioxide

Fractionation of the stable carbon isotopes between dissolved and gaseous carbon dioxide has been measured at temperature 25°C by two methods. In the first method the open system conditions and different methods of CO₂ sampling were arranged. In the second method—the closed system conditions and CO₂ gas extraction were used. The results obtained by these methods are very consistent. Gaseous CO₂ is enriched in heavy isotope by 1.03±0.02 permil in comparison to dissolved carbon dioxide.