oxygen analyser

There are different kinds of O2 sensors. The one often seen in basic process use is the zirconium oxide cell. The attached link is the clearest example I can find

www.gesensing.com/products/resources/whitepapers/OxyTrak_%20411_Paper.pdf -

There are a couple of methods. I have been out of the work for a bit. Used to use these.

Some are condensing and others are burn if memory serves.

Go to www.bacharach.com and look up Fyrite Orsat Oxygen Analyzers. They will answer your question