Traceability in routine chemical measurements: An example of application in the determination of CO2 at atmospheric concentration

Abstract

In routine chemical measurements traceability can be achieved by using analytical instruments calibrated against primary reference materials. In the present work the calibration of a CO2 nondispersive infrared (NDIR) analyzer with measuring range 0-2000 μmol/mol of CO2 and a resolution of 5 μmol/mol is reported. A procedure with working reference gas mixtures (WRMs) has been adopted, which requires seven calibration points. Primary reference gas mixtures (PRMs) are used to validate WRMs in a narrower range around the average atmospheric CO2 concentration value. In this range the relative uncertainty reached is of the order of some parts in 10 3 and the corrections are between 1 μmol/mol and 5 μmol/mol. © 2005 Springer-Verlag Berlin Heidelberg.