Do different inert background gases affect how CO2 concentration is measured?

Yes!  We have found that our CO2 gas analyzer customers, especially in the process and research fields, prefer to have their analyzer calibrated with the background gas that they’ll be using ahead of time.

This is especially true of welding applications.

While it’s easy to calibrate the analyzer based on the effect you see in the field, we can do it for you  before the analyzer ships, and issue a NIST traceable calibration certificate that shows the values at each CO2 concentration value, no matter the background gas.

Just in case you’re curious (as we could not find this data anywhere)  we took an analyzer that was calibrated with 20% CO2 / 80% Nitrogen and found these readings with different background gases:

20% CO2 / 80% Ar reads about 18%  CO2

20% CO2 / 80% He reads about 22% CO2

We have both argon and helium onsite here; if you need us to calibrate the analyzer with Ar, He, or even Xe, we are happy to oblige.