4% PFA

4% Paraformaldehyde in 0.1 M Phosphate Buffer

Laboratory Use Only, Store at 15 – 25 °C

Product Package:

1) 250 ml per unit (Catalog No.: 006775-250); Price: $26.00/each

2) 1,000 ml per unit (Catalog No.: 006775-1L); Price: $77.00/each

(Distributor and quantity discounts available, please send an email to
contact@bioenno.com to order.

For common questions and answers, please check our FAQ.)

General Information:

Grade: Biology
Contents: 4% paraformaldehyde in 0.1 M phosphate buffer
Not hazardous product
CAS # 50-00-0

Product Description:

The 4% paraformaldehyde (PFA) (w/v) is a ready-to-use phosphate buffered formaldehyde solution. It is free of methanol. This solution is directly prepared from granular paraformaldehyde (analytical grade) that is dissolved in 0.1 M phosphate buffer (PB) (pH 7.4) at final neutral pH. Its unique formulation makes it ideal for use in animal perfusion, immunohistochemistry including immunofluorescence (IHC and IF), and histological procedures.

Bioenno develops a unique formulation to prevent polymerization (into paraformaldehyde) of the monomer formaldehyde in the solution, allowing access to “fresh” formaldehyde during its shelf life (up to 2 years at room temperature). The solution can be stored in a refrigerator (4°C), but we recommend storing the solution at room temperature (15 – 25°C).

The standard solution contains 4% paraformaldehyde (at monomer) in 0.1 M phosphate buffer (pH 7.4). Other concentrations can be provided upon request. See also: 4% Paraformaldehyde in DEPC-treated phosphate buffer (Cat # 006782).

Product Features:  

• Compositions: 4% paraformaldehyde in 0.1 M PB (pH 7.4) at final neutral pH
• Methanol-free, with room temperature (15 – 25°C) storage
• Filtered with 0.22 micron membrane and ready-to-use
• Formulated from analytical grade reagents
• Optimized for perfusion of animals, fix of brain tissues and cultured cells/slices
• HDPE bottle (temperature -100°C to 120°C)
• For Research Use Only. Not for food, household, or other uses

 Shipping, Storage, Safety, and Handling Precautions:

• Shipped at room temperature. The solution can be stored in a refrigerator (4°C), but we recommend storing the solution at room temperature (15 – 25°C). The shelf life at 25°C is one year.
• The solution is designed for in vitro research use only and not for drug, diagnostic or other uses.
• The solution contains reagents that may be harmful in contact with skin, by inhalation or ingestion. Do not pipette by mouth. Use ordinary precautions to avoid inhalation and contact with skin and eyes. In case of contact, wash immediately with generous amounts of water and seek medical advice. If swallowed, wash out mouth with water and immediately call a physician.
• Perform experiment under a chemical hood. Wear suitable protective clothing, gloves, and eye/face protection. Wash hands thoroughly after performing the experiment.
• Material safety data sheet (MSDS) is available upon request.

Warranty: 12 months from the date of purchase.

Return Policy: This product can be returned up to 90 days from the date of purchase.

Free Technical Support: Email your questions to contact@bioenno.com

FAQ about 4% PFA  

·      How to use the 4% PFA solution to preserve brain tissue or cells?

Animal perfusion: It is recommended to perfuse animal with saline to flush out blood from the tissue, followed by this 4% PFA solution (RT works perfectly for most cases). Generally, the perfusion may take 15-30 min, requiring 50-250 ml of 4% PFA (mouse/rat as an example).

Fix of neurons via immersion: Add 4% PFA to neurons and incubate for 10-30 minutes at room temperature (15 – 25 °C).

Fix of sections/organotypic slice cultures: Add to sections/slices (the volume of 4% PFA should be approximately 10 times the volume of the tissue) and incubate for 0.5-2 hours, depending on the thickness of sections/slices, at room temperature (15 – 25°C).

·      What is the shelf life of the 4% PFA?

This 4% PFA in 0.1 M PB can be stored at room temperature (RT, 15 – 25°C) for 1 year. Although it can be stored in a refrigerator (at 4°C), we recommend the customer store the solution at RT to prevent possible polymerization of the monomer formaldehyde at cool condition.

·      Is this 4% PFA solution made with DEPC-treated 0.1 M PB? Is it possible to autoclave this PFA solution? Is this PFA solution RNase free?

No, this 4% PFA solution is not made with DEPC-treated 0.1 M PB. It cannot be autoclaved. Although brain tissue perfused with this 4% PFA can be subjected to ISH, resulting in reliable and satisfactory results we recommend the customer use 0.1% DEPC-treated 4% Paraformaldehyde (PFA) (Cat # 006782).

To order 4% PFA solution made with DEPC-treated buffer, please email contact@bioenno.com. We can make a batch with DEPC-treated buffer as a special order, and verify that it is RNase-free.

·      Can I use the 4% PFA to fix my neurons or brain tissue including spinal cord for IHC or ICC?

Yes. Aldehyde-based fixatives (e.g., formaldehyde, glutaraldehyde) crosslink various cellular components, which helps retain proteins and cell morphology, but some antigens may be masked by the crosslinking, requiring antigen retrieval methods to unmask the antigen binding sites. Also, aldehyde-based fixation requires permeabilization (such as via Triton X-100) to allow entry of antibodies.

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