Determination of the purity of gases used in gravimetric preparation of reference gas mixtures
To ensure the future traceability of concentration measurements for the various components of natural gas, LNE is developing reference materials in the form of reference gas mixtures with 11 components, prepared using the gravimetric method.
To calculate the concentrations and associated uncertainties for a gravimetric reference gas mixture, the purity of the gases used to make the gas mixture must be determined.
The purpose of this study is therefore to identify and quantify major impurities present in the pure gas compounds used in making gravimetric reference "natural gas" mixtures. This is done by using a gas chromatograph with a pulse discharge helium ionization detector (PDHID).
This method will enable the laboratory to determine the concentrations of the 11 components of its gravimetric reference gas mixtures with great accuracy.
LNE is equipped with a gas chromatograph with a PDHID.
The study is being performed as follows: