If you work with gases like we do at CO2Meter, you already know that the ideal gas law PV=nRT shows that absolute gas concentration decreases as temperature increases. This relationship is important to anyone measuring oxygen levels during combustion, fermentation, distillation or algae production.
But like they say, “a picture is worth a thousand words.”
That’s what we discovered when we measured the change in oxygen gas levels in a sealed environment using our UVFlux 25% Oxygen sensor and Gaslab software. Using the built-in RS232 protocol, the UVFlux sensor samples both the oxygen level and the temperature inside the sensor once per second.
Over several minutes we raised the temperature of the sample from 24C to 34C, and were able to see in real-time the oxygen concentration in the sample drop from 20.6% to 19.8%.
click image on right for larger view.
Note the internal sensors components are corrected for operating temperature over the range. No compensation is made for the temperature of the gas being measured. Also note the change in oxygen level measured slightly lagged behind the change in temperature.
In addition to temperature, the % relative humidity will have an impact on the oxygen concentration in a sample. At the same pressure and temperature, a volume of oxygen at 100% humidity will contain less oxygen molecules than if there were no water.