3% H₂O₂ endogenous peroxidase block (IHC) recipe
Quenches the tissue's own peroxidase (e.g. in red blood cells) to prevent false brown signal in HRP/DAB IHC.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| 30% hydrogen peroxide (H₂O₂) | 5 mL | 3% |
| Methanol (or PBS) | to final volume |
Steps
- Add 30% H₂O₂ to methanol (or PBS) just before use.
- Soak sections 10–15 min at room temperature, then rinse with water/PBS.
Good to know
- For fragile antigens, use 0.3% H₂O₂ or move this step after antigen retrieval.
- Methanol can damage some surface antigens, so PBS is sometimes used instead.
⚠ Safety 30% H₂O₂ burns skin — wear gloves and goggles.
FAQ
Is it needed for fluorescent IHC?
Not unless HRP is used (e.g. tyramide signal amplification).
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.