7.5% sodium bicarbonate (NaHCO₃) recipe
A bicarbonate stock for making powdered media, which buffers pH together with incubator CO₂.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| NaHCO₃ | 7.5 g | 7.5% (≈0.89 M) |
| Water (distilled) | to final volume |
Steps
- Dissolve in about 80% of the final volume of water.
- Bring to the final volume with water.
- Filter-sterilise through 0.22 µm. (autoclaving converts it to carbonate). Store at 4 °C.
Good to know
- Per medium: DMEM 3.7 g/L (49 mL of 7.5%), RPMI 1640 2.0 g/L (27 mL), MEM 2.2 g/L (29 mL).
- Match medium bicarbonate to incubator CO₂ (5% or 10%).
FAQ
My medium turned purple (alkaline).
CO₂ has escaped — keep caps tight and check the incubator CO₂.
This is a widely used standard composition. Amounts depend on the hydrate form and purity of your reagents — check the formula weight (FW) on the bottle and follow your institution's safety rules and the manufacturers' instructions.