bicarbonate in cell culture: powder v. liquid? - (Dec/13/2009 )

hi, i'm using dmem with hepes added b/c i am culturing out of co2 incubator for about a week. most mediums with bicarbonate have a concentration of 3.7 g/L, which would mess up the pH since I'm not using co2. however, I'm going to make a final concentration of 1 g/L bicarbonate for nutritional purposes.

The basic question is: can I add the bicarbonate just as a powder to the liquid medium? Or do I need to dissolve it in something first and then add?

Sorry for the silly question, I'm new to cell culture.

Thanks!

I was on the Sigma website, and I noticed that you can get the bicarbonate solution (7.5% in water) pre made. Have any of you used this before? Any difference in performance between powder and liquid?

Thanks

bicarbonate solution is not very stable (over the long haul).

but, addition of powder may affect the pH of your medium.

you can prepare and adjust a solution of bicarbonate prior to addition to your medium or you can add powder and check and adjust the pH, as necessary (you may not be adding enough to have a significant effect).

The powder is not sterile.
Adding it can contaminate your medium.
I'd dissolve it first, sterilize it and then add it to the medium.