Patent ID: 7979216

Claim:
Method for determining the compositional origin of a gas G from thermal degradation of carbon materials, wherein at least one carbon material type susceptible to generate the gas G is selected, and a model of carbon isotopic composition is built for a gas P generated by thermal degradation of the selected carbon material type, characterized in that the following steps are performed: the model of carbon isotopic composition is calibrated by calibrating a kinetic effect of reaction independently of a precursor effect, defined as a carbon isotopic composition effect of the carbon material type on a carbon isotopic composition of the gas P generated, by: synthesizing model compounds of the carbon material type, each of the model compounds being an individual compound of an unstable molecular class representative of a chemical composition of the carbon material type and representative of a thermal behavior of the carbon material type; 13 C labeling the model compounds that have been synthesized; and pyrolyzing the model compounds that have been synthesized and labeled; a carbon isotopic composition of gas P generated is estimated, using the model of carbon isotopic composition; a carbon isotopic composition of the gas G is measured; and it is determined whether gas G has been generated from the selected carbon material type, by comparing the measured isotopic composition to the estimated isotopic composition.