Miniprep solution 3 (neutralisation, P3) recipe
Neutralises the lysate so plasmid DNA renatures while genomic DNA, protein and SDS precipitate as a white mass: 3 M potassium acetate, pH 5.5.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| Potassium acetate | 29.44 g | 3 M |
| Glacial acetic acid | as needed | to pH 5.5 |
| Water (distilled) | to final volume |
Steps
- Dissolve potassium acetate in about 50% of the final volume of water.
- Adjust to pH 5.5 with glacial acetic acid (it takes a lot).
- Bring to the final volume with water.
- Store at 4 °C and use cold.
Good to know
- Sambrook Solution III (60 mL 5 M potassium acetate + 11.5 mL glacial acetic acid + 28.5 mL water) does the same job.
FAQ
Does it work with silica spin columns?
Silica columns need a guanidine-containing neutralisation buffer for binding; this one is for alcohol-precipitation minipreps.
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.