4X Laemmli sample buffer recipe
Mixed 1:3 with protein samples before SDS-PAGE to denature them. 250 mM Tris-HCl pH 6.8, 8% SDS, 40% glycerol, 0.02% bromophenol blue, 20% β-mercaptoethanol.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| 1 M Tris-HCl (pH 6.8) | 2.5 mL | 250 mM |
| SDS | 800 mg | 8% |
| Glycerol | 4 mL | 40% |
| Bromophenol blue | 2 mg | 0.02% |
| β-mercaptoethanol (add fresh) | 2 mL | 20% |
| Water (distilled) | to final volume |
Steps
- Mix Tris-HCl pH 6.8, SDS, glycerol and bromophenol blue and make up to 8 mL (without β-ME).
- Aliquot and store at room temperature or −20 °C.
- Just before use, add 200 µL β-ME per 800 µL (or DTT to 100–200 mM final).
- Mix 3 parts sample with 1 part buffer and heat at 95 °C for 5 min.
Good to know
- β-ME is volatile and toxic — handle in a fume hood, or use DTT instead.
⚠ Safety β-mercaptoethanol is toxic — use gloves in a fume hood.
FAQ
Can I make it as 2X or 6X?
Yes — scale each component proportionally. 6X is hard to dissolve because of the high SDS and glycerol.
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.