1 M Tris-HCl recipe
The basic ingredient of most molecular-biology buffers. Dissolve Tris base and titrate to the pH you need (7.4, 7.5, 8.0…) with concentrated HCl.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| Tris base | 60.57 g | 1 M |
| Concentrated HCl | as needed | to pH (pH 8.0 ≈ 42 mL/L, 7.4 ≈ 70 mL/L) |
| Water (distilled) | to final volume |
Steps
- Dissolve Tris base in about 80% of the final volume of water.
- At room temperature, add concentrated HCl slowly until you reach the target pH.
- Bring to the final volume with water.
- Autoclave (121 °C, 20 min) and store at room temperature.
Good to know
- Tris pH is temperature-sensitive (drops ≈ 0.03 per °C). Adjust the pH at the temperature you will use it.
- Some glass electrodes read Tris incorrectly — a Tris-compatible electrode is best.
⚠ Safety Concentrated HCl is corrosive and fuming — use a fume hood, goggles and gloves.
FAQ
Can I use Tris-HCl powder instead of Tris base?
Yes. Mixing Tris-HCl (MW 157.6) with Tris base also works, but titrating Tris base with HCl is usually simplest.
What if I overshoot the pH?
Back-titrating with NaOH changes the ionic composition. For small volumes it is safer to start again.
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.