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NeuroScience Associates

Perfusion Fix Solutions


High quality perfusion fix solutions yield high quality results. Commercially available formaldehyde solutions are NOT fresh and usually have added ingredients to stabilize the solution for long shelf life. This should be considered a “technical grade” perfusion fix solution. Such solutions should only be used for standard, routine, classical stains. However, even these stains may be optimized by having a freshly prepared perfusion solution using reagent grade components.

Preferred Perfusion Fix Solution

Phosphate-Buffered Paraformaldehyde:


Order from EM Sciences, call (215) 412-8400; catalog # 1224SK.
Prepare in the lab:

For 1000 ml TotalFor 2000 ml TotalFor 4000 ml TotalFinal %
Paraformaldehyde40 g80 g160 g4%
Phosphate Buffer
0.2M; pH 7.2
500 ml1000 ml2000 ml--
Note: Not to be used for the purpose of cryoprotection
40 g80 g160 g4%

For 1000 ml Total:

  1. Begin with 500 ml of dH20 and heat to 60°-65°C (~104° F) on a heater/ magnetic stirrer.
  2. Add the sucrose. Please note: Sucrose is optional and this solution is not to be used for cryoprotection.
  3. Create a deep vortex using a magnetic stirrer bar. Gradually sprinkle the finely powdered paraformaldehyde onto the vortex surface. The solution will be quite milky.
  4. Allow to cool to room temperature
  5. Bring the total volume to 1000 ml with 0.2M Phosphate Buffer and verify the pH.
  6. Filter the solution using a qualitative paper.

For more information:

Antigen Preserve (AP) Solution

Mounting Solutions

Post-Fixative (Storage) Buffer Solutions


Contact Technical Support at NSA Labs via this form or call 865.675.2245 for shipping and preparation questions.