I am currently working on a project measuring gas composition of car exhaust. In order to dilute the gas concentration down to something electrochemical sensors can read, I diluted the sample with pure helium.
The following is true for these sensors:
Importance of Oxygen. The reactions at the sensing electrode (anode) for some gases are as follows: \begin{align} \ce{CO + H2O &-> CO2 + 2H+ + 2e-} \\ \ce{H2S + 4H2O &-> H2SO4 + 8H+ + 8e-} \\ \ce{NO + 2H2O &-> HNO3 + 3H+ + 3e-} \\ \ce{H2 &-> 2H+ + 2e-} \\ \ce{2HCN + Au &-> HAu(CN)2 + H+ + e-} \end{align} Simultaneously, the reactions at the counter electrode (cathode) need oxygen molecules to complete the process: $$\ce{O2 + 4H+ + 4e- -> 2H2O}$$ An inadequate supply of oxygen to complete the reaction will shorten the life of the sensors, hence the sensors will not operate properly.
Does this mean that doing what I intend is going to affect their performance and damage them?