Tra#abilité nationale et internationale des mélanges de gaz de référence

摘要

All measurements, and namely chemical analyses, need references in order to ensure demonstrated traceability to the relevant base units. This is a condition made essential to guarantee accuracy of measurement results. In the field of gas analyses, this metrological approach has made good progress, compared to the majority of other types of chemical analyses. On the international level, the Comité Consuhatif pour la Quantité de Matière (CCQM), within the frame of the Comité International des Po/ds et Mesures (CIPM), established the first comparability, of CO, CO2, NO and SO2 measurements in Nitrogen, between national metro-logy laboratories with experience in this field. BNM-LNE, in charge of metrology in chemistry in France. has been developing methods of preparation of gravimetric gas mixtures and high-level comparison methods for ten years. Therefore, our lab was able to take part in this action, thereby demonstrating traceability of our standard gas mixtures, and confirming our competence as a 'reference laboratory' for metrology of gases. Our results were found in good agreement with those from other participating laboratories, and with measurement errors much lower than the preset level of/% relative. On the national level, BNM-LNE has been transferring this traceability towards the manufacturers of calibration gas mixtures .' companies Air Liquide and AGA are now linked to the national calibration chain BNM-COFRAC for the production of Calibrated Reference Gas Mixtures. Other producers are presently working towards that same objective. Thus, the availability of these Reference Materials make users laboratories able to calibrate or assess the accuracy of their gas analyses.