Method of determining an isotope ratio

摘要

A method of determining an isotope ratio, comprising providing a reference gas at a first known isotope ratio; measuring the isotope ratio of the reference gas with the first known isotope ratio at a plurality of concentrations in a carrier gas; determining a concentration dependence of the isotope ratio measurements of the reference gas with the first known isotope ratio; providing a sample gas of unknown isotope ratio and unknown concentration; measuring the isotope ratio and concentration of the sample gas; and correcting the measured isotope ratio of the sample gas by the determined concentration dependence. The sample gas is preferably diluted in the carrier gas prior to measuring its isotope ratio.