I've been experiencing cell culture death . I excluded all factors and it came down to incubator calibration now. Temperature is ok but no one is available to calibrate Carbon dioxide level due to lockdown. Is there a any procedure that I can do in the lab to give me an indicator about Carbon dioxide level in incubator
A simple method would be to add a beaker of distilled water to the incubator, open to the atmosphere, and let it equilibrate with the air in the incubator - mix occasionally by hand, or place on a stirring plate in the incubator (or sparge with an aquarium pump that is placed in the incubator - this will ensure equilibrium is reached in a few hrs (or a day). If you don't mix, Sample each day to make sure you have reached equilibrium. When you sample, remove 25 mL and titrate with base (NaOH) to determine the acidity. You can find more on acidity/alkalinity titrations in Standard Methods for the Examination of Water and Wastewater (APHA). The most difficult part is standardizing the NaOH and keeping it free of CO2. You need to standardize the NaOH by titrating with HCl. Standard Methods also has information on this. Since the acidity is due to CO2 (which converts to H2CO3 during the titration), by pH 10.3 you have added 2 NaOH for every 1 CO2 in the water phase. Before titration measure the initial pH also. From the initial pH and the acidity measured by titration, you can calculate all carbonate species concentrations in the water, and the concentration of CO2 in the gas phase within the incubator. Pure water in equilibrium with air has a pH of 5.6 due to CO2 at 400 ppmv in air. Find this calculate on the web, and you can do the same for your conditions.
Thanks so much for the extensive and comprehensive helpful answer.