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 13C by 1.03±0.02 permil in comparison to dissolved carbon dioxide.