A preliminary experimental study has been made to determine the factor affecting the stability of reactive calibrations gas mixtures. The model system selected for study was nitric oxide (NO), at various concentrations in nitrogen, argon, and helium as the inert diluting gas. Quantitative data have been obtained which indicate that cylinder conditioning and concentration of the mixture are major factors affecting shelf life. Total mixture pressure and temperature cycling appear to play a minor role in stability, except at low parts-per-million concentrations. No major differences were found in comparing mixture stability in stainless versus chrome-molybdenum steel.

It was observed that the chemiluminescence detecting principle for determining NO appears sensitive to the inert matrix gas used in mixtures. The measured concentration of NO in the mixture varies with the molecular weight of the inert gas.