Development of a New Type of Reference Standard for Carbon Isotopic Composition

The development of a new type of reference standard for carbon isotopic composition consisting of 12CO2 + 13CO2 and N2 gaseous mixtures in tanks under pressure is discussed. These standards are required for measuring the isotope ratio 13C/12C in gaseous mixtures of CO2. The procedures for preparing and verifying the reference standards are described and their stability is tested. These standard samples can be used for calibrating (testing) isotopic infrared analyzers and mass spectrometers.