Fractionation of stable oxygen and clumped isotopes during acid digestion of calcite in the presence of an external direct current electric field.

We documented the systematic control of oxygen and clumped isotope ratios in CO2 evolved from the carbonate acid digestion reaction with varying exposure time to the external electric field. We provide a new method involving use of an external electric field to manipulate the isotopic fractionation during the acid digestion reaction of calcite. The experimental observation enabled theoretical understanding of the reaction mechanism of carbonate with phosphoric acid which will be useful for stable and clumped isotope studies.