ISO/NP 6145-12

Gas analysis — Preparation of calibration gas mixtures using dynamic methods — Part 12: Chemical reaction method

Scope

ISO 6145 is a series of documents for various dynamic methods for the preparation of calibration gas mixtures. This document specifies the method of preparing a component of interest by chemical reaction method and continuously introducing it into the complementary gas to prepare a calibration gas mixture.
This document elaborates the principles of the chemical reaction method, specifies the reagents and materials required in the preparation process of calibration gas mixtures, the preparation device, requirements for preparation safety, preparation procedures, calculation method for the content (amount-of-substance fraction) of component of interest, calculation method for reaction conversion efficiency and verification requirements for gas mixtures, establishes uncertainty evaluation methods, and and the method for verifying the finally prepared calibration gas mixtures.
This document is applicable to the preparation of calibration gas mixtures with component content ranging from 10-9 mol/mol to 10-4 mol/mol. The relative expanded uncertainty of the component of interest in calibration gas mixtures prepared using the method given in this document is not greater than 5%.
This document is applicable to chemical reactions that can theoretically occur rapidly. The conversion efficiency of the reactions is not less than 97%.
This document is not applicable to electrochemical reactions.