Interlaboratory test for stable carbon isotope analysis of dissolved inorganic carbon in geothermal fluids.
Mahendra P VermaRobert van GeldernMatheus C CarvalhoFausto GrassaAntonio Delgado HuertasGaël MonvoisinDaniel CarrizoPublished in: Rapid communications in mass spectrometry : RCM (2020)
The δ13 C values of solid Na2 CO3 and its solution, and lake water (i.e. DIC concentration samples >100 mg/L carbon) are consistent among all the participating laboratories. The dispersion in the δ13 C values of solid CaCO3 is associated with its lower chemical affinity than that of Na2 CO3 . The poor reproducibility in the δ13 C values of geothermal fluids, collected at three points of a geothermal well, despite overall consistent trends regarding their collection points suggests inadequate sample handling (atmospheric CO2 exchange) and/or inappropriate analytical approaches (incomplete H3 PO4 acid reaction).