I am using the NaHCO3 buffer + CO2 to maintain pH 7.0 to 7.4 in cell culture condition.
Hi Murali ,N-tris (hydroxymethyl) methyl-2-aminoethanesulphonic acid (TES) and N-2-hydroxyethylpiperazine-N'-ethanesulphonic acid (HEPES) are very soluble, have low binding capacities for divalent cations, stable and covering a pKa range from 6 to 8.
regards
Ehab is correct. I would use HEPES. It seems to best tolerated, but you will need to titrate to the desired pH at 37 degrees and under CO2. Otherwise you might get a different pH than you intended. You can also try a mix of mono and dibasic sodium phosphate as buffer. Again, final pH has to be checked under CO2 at 37C. Do not exceed 10 mM or you will be precipitating calcium phosphate. Good luck.
If I understand your question, you are trying to swing your pH from neutral to high/low? If so, it depends on the pH range swing you need and how stable you need that buffer to be at the various pHs. For large pH swings, I like Sodium Citrate as it has 3 different usable pHs, PIPES has a broad biological pH range from 6.8-9.2, though HEPES will also work. If you need to have a lower pH you can use MES.
In the absence of other pH buffering chemicals, pH in your solution is eventually determined by the ratio between the concentration of NaHCO3 and the % of CO2 in your incubator. HEPES, which has a pKa of 7.50 at room temperature, is a very good supplemental pH-buffering chemical for cell culturing. Adjust the HEPES containing solution to your target pH before adding the calculated amount of NaHCO3. In the presence of HEPES (e.g. 20 mM), adding the NaHCO3 last will only make the solution slightly more alkaline than the target pH, which can be restored in the CO2 incubator.
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