Complementary comparison on ethanol in nitrogen

Project Description

This comparison is a repeat of EUROMET.QM-K4. It serves to demonstrate capabilities of participants in the analysis of ethanol in nitrogen mixtures. NMi-VSL will produce the gas mixtures to be analysed. Both NMi-VSL and NPL have also participated in EUROMET.QM-K4 and can provide a link between the 2 comparison.

Final Report 2011-05-17

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

Ethanol measurements in human breath are important for the implementation of legal metrology related to the driving under influence legislation. Measurements are typically performed to calibrate breath testers in accor-dance with OIML Recommendation R126:1998 (evidential breath analysers) in the range from 50 µmol/mol up to 800 µmol/mol ethanol in nitrogen or air.
Six national metrology institutes participated. The KCRV is based on the gravimetric preparation. Its uncertainty appreciates effects from adsorption of ethanol to the cylinder wall, weighing, and purity analysis. Only VNIIM shows a result which is inconsistent with the KCRV. Both VNIIM and CEM show a result that deviates more than 1% from the reference value.
This Euramet comparison is linked to CCQM-K4; as NPL and VSL participated in both comparisons, this can provide a link between the two comparisons.