I've been experiencing massive cell death in my human iPSCs lately. I excluded all factors and it came down to incubator calibration now. Temperature is O.K but no one is available to calibrate Carbon dioxide level due to COVID-19 lockdown. Is there a simple procedure that I can do in the lab to give me an indicator about Carbon dioxide level in my incubator?. Thanks
We used to use one of these devices as a backup analyser of CO2:
https://www.mybacharach.com/product-view/fyrite-classic/
Dear Summer,
Please find the RG link for more information.
https://www.researchgate.net/post/Can_anyone_assist_with_measuring_CO2_within_an_incubator
https://www.researchgate.net/post/What_do_you_use_for_CO2_measurement
If it is difficult to buy some equipment because of lockdown, prepare multi PH indicator solution, put it in the small beaker, put the beaker in your and neighbor's CO2 incubator (working) at the same time, and see it after a while. If the color indicates not so acidic, at least you can know that CO2% is not okay.
Cell culture media are generally supplemented with Phenol Red to act as a pH indicator. The colour of the medium helps advise if cultures are at physiological pH and can assist with troubleshooting.
In addition easiest and most accurate method to measure the CO2 level in an incubator is with a gas analyzer such as a Fyrite® device. These can be purchased from many scientific supply houses and are available in models designed to measure CO2 or O2 levels. The operation of the gas analyzer is based on the volume expansion of a fluid following the chemical absorption of the gas to be measured. The device is ‘zeroed’ using room air (0.04% CO2), and the air in the incubator is sampled through a port in the door or side of the incubator.
The pH changes during cultivation due to lactic acid production, CO2 production and other net acidic products...
Buffers used in cell culture media to stabilize pH
Sodium hydrogen carbonate (main buffer)
Hepes (limited to < 50 mM due to toxicity)
Choose medium correctly from ATCC or whatever well trusted companies..
I just answered a similar question. For almost no money, you can equilibrium deionized water in the incubator and perform an acidity titration on it. To make sure the water is saturated, mix it somehow, or aerate the water with an aquarium pump while it is in the incubator. Titrate with NaOH to a pH of 10.3. At this point for every 2 mmoles of NaOH added, you have converted 1 mmole of CO2 (H2CO3) to carbonate (CO3(2-). You will need to record the pH before titration (which will be below 5.6 if the air in the incubator has more CO2 than the air outside the lab), and you will need to standardize the NaOH, as it picks up CO2 from the atmosphere when you prepare it. Standard Methods for the Examination of Water and Wastewater has a method for standardizing NaOH, and discusses alkalinity/acidity titrations. No expensive instruments needed (except for a typical pH meter and good combination pH probe). From this you can calculate all carbonate species in the distilled water (mostly CO2), and with Henry's constant, you can calculate the concentration of CO2 in the gas phase in the incubator.