Comparison on Carbon dioxide mixtures in nitrogen

Project Description

This comparison serves to demonstrate the capabilities of IPQ in the production of primary gas mixtures of Carbon dioxide in nitrogen and to INRIM, METAS(?), MKEH, INMETRO, NPLI, NMIT demonstrate the capabilities on certifying primary gas mixtures of percent levels of Carbon dioxide in nitrogen.

INRIM, METAS(?), MKEH, INMETRO, NPLI, NMIT and ITRI will analyse the gas mixtures that are gravimetrically produced and analysed by IPQ.

The pressure in the cylinders will be approximately 100 bar; cylinders of 5 dm3 nominal will be used. Each cylinder will have its own reference value calculated from the gravimetric preparation.

Participating laboratories are requested to specify in detail the calculation of the analyzed composition and how the evaluation of uncertainty was performed.

Final Report 2012-09-25

The comparison has been completed and results are published in the KCBD.

This project is finished. The results in summary:
The capabilities for the certification of certified reference materials of carbon dioxide in nitrogen have been compared. The participating national metrology institutes analysed each a gas mixture of a specified target composition gravimetrically prepared by the coordinating laboratory. All mixtures were gravimetrically prepared and analysed by the coordinating laboratory using a gas chromatograph equipped with a thermal conductivity detector and a non dispersive infrared spectroscopy in three runs under repeatability conditions. Based on the calibration curve, reference values were assigned to the amount fractions of carbon dioxide. The degrees–of–equivalence were established as difference between the gas composition as calculated from preparation and the measured one, and its associated uncertainty. All participants except one obtained satisfactory results.