Paraformaldehyde | PFA | Reagent Grade | White Crystalline Solid
Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units.
- Solubility in water: low
- Melting point: 120 °C (248 °F; 393 K)
- Chemical formula: OH(CH2O)nH (n = 8 - 100)
- CAS Number: 30525-89-4
- Synonym: Polyoxymethylene
- Paraformaldehyde (PFA) SDS/MSDS
- Chemical And Physical Basics Of Routine Formaldehyde Fixation | Conversion Of Methylene Glycol To Active Carbonyl Formaldehyde
- Flake/Crystalline/Granular/Powder Form
- High Purity Reagent Grade And Lab Grade Paraformaldehyde
Paraformaldehyde Flake | Lab Grade Features:
|Formaldehyde Content||Min. 90%|
|Acidity (as HCOOH)||0.03%|
Paraformaldehyde Flake lab Shipping Information:
DOT: Paraformaldehyde, 4.1, UN2213, PG III
Paraformaldehyde is the condensation product of methylene glycol, a substance not so far isolated in its pure form; it is a white solid with a formaldehyde content between 78 and 98% and is supplied either as a Prill or Granular. All forms contain more than 95.5% paraformaldehyde content.
Paraformaldehyde forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold. Formalin actually contains very little monomeric formaldehyde; most of it forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization.
Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating and to formaldehyde solution by water in the presence of a base or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating paraformaldehyde is flammable.
Once paraformaldehyde is depolymerized, the resulting formaldehyde may be used as a fumigant, disinfectant, fungicide, and fixative. Longer chain-length (high molecular weight) polyoxymethylenes are used as a thermoplastic and are known as polyoxymethylene plastic (POM, Delrin). It was used in the past in the discredited Sargenti method of root canal treatment.
Paraformaldehyde is not a fixative; it must be depolymerized to formaldehyde in solution. In cell culture, a typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes. In histology and pathology specimens preparation, usually, the fixation step is performed using 10% Neutral Buffered Formalin (4% formaldehyde) for, at least, 24 hours.
Paraformaldehyde is also used to crosslink proteins to DNA, as used in ChIP (chromatin immunoprecipitation) which is a technique to determine which part of DNA certain proteins are binding to.
Paraformaldehyde can be used as a substitute of aqueous formaldehyde to produce the resinous binding material, which is commonly used together with melamine, phenol or other reactive agents in the manufacturing of particle board, medium density fiberboard and plywood.
As a formaldehyde releasing agent, paraformaldehyde is a potential carcinogen. Its acute oral median lethal dose in rats is 592 mg/kg.