Analysis of impurities in pure and balance gases used to prepare primary standard gas mixtures by the gravimetric method
Project Description
This project builds on the results of EUROMET project 867 on purity analysis of nitrogen. For EUROMET 867 the amount fractions of the impurities in the nitrogen were higher than normally found in "high purity" nitrogen. This project will be carried out at more realistic values for the impurity amounts. Target values are:
20-50 nmol/mol CO
20-50 nmol/mol CO2
20-50 nmol/mol CH4
50-100 nmol/mol O2
1-5 µmol/mol Ar
100-200 nmol/mol H2O
All participants will analyse for CO, CO2, CH4, O2 and Ar. Analysis of water vapour will be optional.
A small batch of samples will be purchased from a well-qualified supplier of specialty gases. The listed components are expected to be present in the pure nitrogen at the target levels as a result of the purification of the nitrogen. The manufacturer will be asked to target the CO, CO2 and CH4 fractions as closely as possible. The O2, Ar and H2O fractions will be more difficult to target. This comparison may not lead to reference values for the constituents analysed.
Final Report 2013-10-18
The comparison has been completed and results are published in the KCDB.