I need to prepare a 10% oxygen in nitrogen mixture for an aerobic reaction I'm developing in lab and I found an old instrument in someone else's lab that controls the flow of two gases. So I am able to control the "percentage" of both gases in the mixture using this manifold.
However, I want to test whether or not that thing is calibrated and how exact/precise it is since I don't want to report in a paper that I'm using 10% oxygen when it is actually 20 or 30 or 50%. What is the easiest way to determine the percentage/partial pressure of this gas mixture that will give me reliable results?
I thought about physical-chemical methods such as weighing the mixture and based on basic thermodynamic equations determine its partial pressures but I think a chemical method would be more interesting, such as reacting a known volume of gas with something that would consume the oxygen in a known stoichiometry. Any ideas?