Using Isotopic Disequilibrium of CO2 to Model Gas Adsorption in Mass Spectrometric Measurements.

Measurements carried out on a CO2 sample prepared by mixing known amounts of natural CO2 with CO2, enriched in 13-C and, to a lesser extent, in 17-O and 18-O, revealed that the mixture was not in isotopic equilibrium. This occurs for samples of any gas containing more than one isotopically exchangeable atom in the molecule, prepared by mixing gases with different isotopic composition. As a consequence, it was impossible to derive the mean isotope ratios from the measurement because the equations normally used for data reduction assume that isotopic equilibrium takes place, i.e. the isotopic species distribution obeys the statistical probability.

GONFIANTINI Roberto;  VALKIERS Staf;  TAYLOR P.D.P.;  DE BIEVRE P.; 

1996-07-29

JRC12794