PARAFORMALDEHT 91% (PARAFORMALDEHYDE 91%)

PARAFORMALDEHT 91% (PARAFORMALDEHYDE 91%)

Paraformaldehyde 91% (Paraformaldehit 91% )

synonyms:

Paraformaldehit 91%; paraformaldehyde; para formaldehyde; para form aldehyde; peraformaldehyde; pera form aldehyde; pera formaldehyde; paraformaldehit; para formaldehit; para form aldehit; Paraformaldehyde; Para Formaldehyde; Para Form Aldehyde; Peraformaldehyde; Pera Form Aldehyde; Pera Formaldehyde; Paraformaldehit; Para formaldehit; Para Form Aldehit; PARAFORMALDEHIT; PARA FORMALDEHYDE; PARA FORM ALDEHYDE; PARAFORMALDEHYDE; PERA FORM ALDEHYDE; PERA FORMALDEHYDE; PARAFORMALDEHYDE; PARA FORMALDEHIT; PARA FORM ALDEHIT; formalin; methanal; formol; methylene oxide; paraformaldehyde; oxomethane; paraform; formic aldehyde; oxymethylene; methyl aldehyde; Polyoxymethylene; Polyoxymethylene; metaformaldehyde; paraform; formagene; paraffinize; paraffinoid; paraffinoma; parafoil; parafollicular cell; paraformaldehyde; paraganglioma; paraganglion; paragenesis; parageusia; paraglide; paraflutizide; parafoil; parafoils; parafollicular; paraformaldehyde; paraformer; paraformers; parafoveal; parafransoletite; paraganglia; formaldehyde; formalin; methanal; formol; Paraformaldehyde; Formaldehyde; Formalin; Formol; Methanal; Oxomethane; formaldehyde; formalin; methanal; formol; Paraformaldehyde; 50-00-0; Methylene oxide; Oxomethane; Paraform; Formic aldehyde; Oxymethylene; Methyl aldehyde; Fannoform; Formalith; Formaldehyde solution; Methaldehyde; Superlysoform; Formalina; Lysoform; Morbicid; Karsan; Formaldehyd; Formaline; Oxomethylene; Polyoxymethylene; Aldehyde formique; FYDE; Formaldehyde, gas; Formalin 40; Aldeide formica; 30525-89-4; Oplossingen; Dormol; Polyformaldehyde; Formalin-loesungen; Paraformic aldehyde; Rcra waste number U122; Aldacide; Aldehyd mravenci; Paraformaldehydum; Oilstop, Halowax; Flo-Mor; CH2O; UN 2209 (formalin); Formaldehyde (gas); Formaldehyde polymer; Formaline [German]; NCI-C02799; Formalina [Italian]; Oplossingen [Dutch]; HCHO; Caswell No. 465; Caswell No. 633; FORMYL GROUP; Polyoxymethylene glycol; Polymerised formaldehyde, Fordor; UN 1198; Aldehyd mravenci [Czech]; POLY(OXYMETHYLENE); Aldeide formica [Italian]; Aldehyde formique [French]; Formalin-loesungen [German]; Formaldehyd [Czech, Polish]; CCRIS 315; NSC 298885; Formaldehyde [USP]; HSDB 164; Aldehyde formique [ISO-French]; BFV; Formaldehyde, solution; Paraformaldehit 91% ; UNII-1HG84L3525; CHEBI:16842; AI3-26806; HSDB 4070; Paraformaldehyde, polymer; UN1198; UN2209; UN2213; RCRA waste no. U122; EPA Pesticide Chemical Code 043001; EPA Pesticide Chemical Code 043002; Formalin Solution; UGFAIRIUMAVXCW-UHFFFAOYSA-N; WSFSSNUMVMOOMR-UHFFFAOYSA-N; Formaldehyde, Para; Formaldehyde (USP); MFCD00003274; 1HG84L3525; Formaldehyde, solution (37% to 50%); Formalde-Fresh Solution; DSSTox_CID_637; Formalin, Buffered, 10%; DSSTox_RID_82549; DSSTox_GSID_47796; CAS-NOCAS_47796; Formaldehyde, 37% by Weight; Formaldehyde, 40% by Volume; Paraformaldehyde, 90%, pure; Formaldehyd (CZECH, POLISH); Formalde-Fresh Solution, Buffered; Formalaz; Formaldehyde, solutions, flammable [UN1198] [Flammable liquid]; MFCD00133991; Formaldehyde, solutions with not =36.5%; Formaldehyde solution, for molecular biology, 36.5-38% in H2O; Formaldehyde solution, meets analytical specification of USP, >=34.5 wt. %; Formaldehyde solution, puriss., 37.0%, contains 6.0-9.0% Methanol; Formaldehyde solution, AR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, contains 10-15% methanol as stabilizer, 37 wt. % in H2O; Formaldehyde solution, for molecular biology, BioReagent, >=36.0% in H2O (T); Formaldehyde solution, JIS special grade, 36.0-38.0%, contains methanol as stabilizer; Formaldehyde solution, LR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, SAJ first grade, >=35.0%, contains methanol as stabilizer; Formalin solution, neutral buffered, 10%, case of 24 x 60 mL, histological tissue fixative; Formalin solution, neutral buffered, 10%, case of 48 x 15 mL, histological tissue fixative; Formaldehyde solution, ACS reagent, 37 wt. % in H2O, contains 10-15% Methanol as stabilizer (to prevent polymerization); Formaldehyde solution, meets analytical specification of Ph.??Eur., BP, 35 wt. %, contains 10% methanol as stabilizer; Formaldehyde solution, meets USP testing specifications, contains 9.0-15% methanol as stabilizer; Formaldehyde solution, stabilized with methanol, ~37 wt. % in H2O, certified reference material; Formalin solution, neutral buffered, 10%, case of 24 x 120 mL, histological tissue fixative; Paraformaldehyde 91% ; Paraformaldehyde 91; PARAFORMALDEHYDE 91; Paraformaldehyde %91; para formaldehit %91; paraformaldehit %91; paraformaldehit 91; paraformaldehite %91; para formaldehite %91; para formaldehite 91; Paraformaldehit 91%; PARAFORMALDEHT 91%

PARAFORMALDEHYDE 91%

Paraformaldehyde 91%

Not to be confused with Paraldehyde.

Paraformaldehyde 91%

Paraformaldehyd.svg

Names

IUPAC name

Polyoxymethylene

Identifiers

CAS Number

30525-89-4 ☑

ChemSpider

none

ECHA InfoCard 100.108.270

PubChem CID

24898648

CompTox Dashboard (EPA)

DTXSID8034798 Edit this at Wikidata

Properties of Paraformaldehyde 91%

Chemical formula of Paraformaldehyde 91%

OH(CH2O)nH (n = 8 – 100)

Appearance of Paraformaldehyde 91% white crystalline solid

Density of Paraformaldehyde 91%1.42 gcm-3 (25 C)

Melting point of Paraformaldehyde 91% 120 C (248 F; 393 K)

Solubility of Paraformaldehyde 91% in water

low

Hazards

Safety data sheet Oxford MSDS[dead link]

EU classification (DSD) (outdated)

Toxic (T); Corrosive (C)

Except where otherwise noted, data are given for materials in their standard state (at 25 C [77 F], 100 kPa).

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Infobox references

Paraformaldehyde 91% (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8-100 units. Paraformaldehyde 91% commonly has a slight odor of formaldehyde due to decomposition. Paraformaldehyde 91% is a poly-acetal.

Synthesis

Paraformaldehyde 91% 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 Paraformaldehyde 91% forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization.

Reactions

Paraformaldehyde 91% can be depolymerized to formaldehyde gas by dry heating[1] 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 91% is flammable.

Uses

Once Paraformaldehyde 91% 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.[2]

Paraformaldehyde 91% 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 91% 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 91% 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.[3]

Toxicity of Paraformaldehyde 91%

As a formaldehyde releasing agent, Paraformaldehyde 91% is a potential carcinogen.[4] Its acute oral median lethal dose in rats is 592 mg/kg.[5]

See also

1,3,5-Trioxane (metaformaldehyde), the cyclic trimer of formaldehyde

General description of Paraformaldehyde 91%

Paraformaldehyde 91% is also referred as polyoxymethylene. It participates as an external CO source in the synthesis of aromatic aldehydes and esters.[4]

Paraformaldehyde 91% is an ideal fixative used in histology.[7] It is generally preferred over other fixative as the others result in more silver grains on the tissues. Paraformaldehyde 91%, appropriately combined with DMSO (dimethyl sulfoxide) ensures its uniform distribution over the tissue section.[7] Paraformaldehyde 91% is also used in recognizing and stabilizing the expression of intracellular antigen.[6]

Application of Paraformaldehyde 91%

Paraformaldehyde 91% has been used as a fixative[8][10][11] in histological analysis.[9] Paraformaldehyde 91% has also been used in mitotic catastrophe assay.[5]

Paraformaldehyde 91%

Paraformaldehyde 91% is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as paraform`, formagene`, para`, polyoxymethane`).

Properties of Paraformaldehyde 91%

86%Paraformaldehyde 92%Paraformaldehyde

Chemical Formula HO(CH2O)nH

Molecular Weight n=2~100 (Melecular weight differs with number of `n`)

Appearance or other feature White, granular solid, pungent odor

Specific Gravity (true specific gravity) 1.25～1.35 1.30～1.40

Boiling Point (℃ 30mmHg) No data

Freezing Point (℃) 80～160 120～170

Flash Point (℃) Approx. 63 Approx. 93

Ignition Temperature (℃) Approx. 300

Dust Explosion: Lower Explosive Limit 40g/m3

Minimum Ignition Energy 20mJ

Solubility Hardly soluble in water, readily soluble in hot water

Stability&

Reactivity Highly reactive substance; mainly produces methylol and methylene compounds.

Paraformaldehyde 91% is a free flowing white granules or powder with the molecular formula (CH2O)n. It is mainly used as a raw material for manufacture of resins for plastics (e.g. molding powders) and for the wood industry. Paraformaldehyde 91% is also suitable for the manufacturing of paints, varnishes, coatings, dyes and other specialty chemicals, and it may also be used as a bactericide and fungicide.

Paraformaldehyde 91%(PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8-100 units. Paraformaldehyde 91%commonly has a slight odor of formaldehyde due to decomposition. Paraformaldehyde 91%is a poly-acetal. Contents Synthesis Reactions Uses Toxicity See also References Synthesis Paraformaldehyde 91%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. Reactions Paraformaldehyde 91%can be depolymerized to formaldehyde gas by dry heating[1] 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 91%is flammable.

Uses

Paraformaldehyde 91%Paraformaldehyde 91%is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as paraform`, formagene`, para`, polyoxymethane`). From: Materials Science for Dentistry (Tenth Edition), 2018 Related terms: TissuesAntibodyProteinGlutaraldehydeTriton X 100Fixative View all Topics Download as PDF Set alert About this page Learn more about Paraformaldehyde 91%Gene Probes Joseph T. McCabe, Donald W. Pfaff, in Methods in Neurosciences, 1989

4% Paraformaldehyde 91%in PBS Paraformaldehyde 91%powder is dangerous to mucous membranes. When handling, avoid contact with eyes, wear gloves and a mask. To prepare Paraformaldehyde 91%fixative, warm PBS up to 65C. Only then, with vigorous stirring, slowly add paraformaldehyde. Add 160 g paraformaldehyde/4 liters PBS, 40 g paraformaldehyde/1000 ml PBS, or 32 g/800 ml PBS. Gradually add a few drops of 6 M NaOH as a final clearing step, then filter with fluted filter paper. Do not allow the temperature of the Paraformaldehyde 91%solution to exceed 68C and do not prepare Paraformaldehyde 91%too long before use (longer than 1 month) since it will polymerize. An alternative procedure is to prepare 2 Paraformaldehyde 91%in water. This Paraformaldehyde 91%will not polymerize as quickly, and can be used by diluting with 2 PBS.

1 Fixatives a “Karlsson-Schultz”: 2.5% Glutaraldehyde/4% Formaldehyde in Phosphate Buffer pH 7.3 According to Karlsson and Schultz (1965) Paraformaldehyde 91%(16%) stock solution: Mix 80 g Paraformaldehyde 91%with 450 ml H2O. Stir at 60C for 15-20 min. Add droplets of 1 M NaOH until solution turns clear. Add H2O to a final volume of 500 ml. Filter with a NalgeneTM filter unit and freeze aliquots for storage (-20C). Thaw aliquots at 60C for use, the solution should be clear. Fixative working solution (200 ml): 0.36 g NaH2PO4∙H2O.

The amount of glutaraldehyde in this fixing solution can be reduced to 0.2% when samples should be processed for immunoelectron microscopy. In case of sensitive antigens, glutaraldehyde can also be omitted, but this will result in a less-preserved ultrastructure. An excellent and detailed protocol for cryosectioning according to Tokuyasu (1973) and immunolabeling of thawed cryosections is provided by Peters and Pierson (2008) and therefore not explained further here. b “Perfixol”: 5% Glutaraldehyde/4% Formaldehyde in Cacodylate Buffer pH 7.2 According to Griffiths et al. (1981 Buffer (0.08 M Na-cacodylate, pH 7.2): Dissolve 8.56 g Na-cacodylate in 450 ml H2O. Adjust pH to 7.2 with 1 M HCl. Add H2O to a final volume of 500 ml. Fixative working solution (500 ml): 150 ml 0.08 M cacodylate buffer 250 ml 8% Paraformaldehyde 91%in H2O (final: 4%) 100 ml glutaraldehyde 25% in H2O, EM-grade (final: 5%) 0.33 g CaCl2∙2H2O Filter with a NalgeneTM filter, adjust pH to 7.2 if necessary. Embryo dishes (preferably black, if used for small, quasi-transparent samples) or crystallization dishes (e.g., from Agar, Stansted, U.K.); -0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with 2 mM sucrose; 0.05-0.1 M phosphate buffer, optionally supplemented with 2 mM sucrose and/or 0.02 mM magnesium sulfate; 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3, pH 7.8 (Hydra culture medium); Urethane was from Sigma-Aldrich, Inc (St Louis, U.S.A.); Paraformaldehyde 91%(Sigma-Aldrich), glutaraldehyde, OsO4 crystals, epoxy resins (Epon, Spurr`s) were from Sigma-Aldrich (St Louis, MO), Agar-Scientific (Stansted, England), EMS (Hatfield, PA), Polysciences (Warrington, PE), or Ted Pella (Redding, CA). B Chemical Fixation 1 Chemicals (be aware that most of the reagents are more or less toxic and/or hazardous to health; for their safe use and disposal consult the relevant Material Safety Data Sheets) 0.05-0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with varying concentrations of sucrose. 0.05-0.1 M phosphate buffer, optionally supplemented with varying concentrations of sucrose and/or magnesium sulfate. Hydra culture medium: 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3; pH 7.8 (all Sigma-Aldrich or Merck). Urethane and 1-phenoxy-2-propanol (Sigma-Aldrich).

D Preparation of Skin Tissue for In Situ Hybridization Paraformaldehyde 91%is yet another method of fixation that allows for morphological and histological analyses, including in situ hybridization. Samples harvested for these types of experiments should be fixed immediately for optimal results. It is essential that tissues be handled quickly with RNAse-free instruments to protect against RNA degradation.

Samples should be immediately fixed in 4% Paraformaldehyde 91%that was freshly prepared in DEPC-treated H2O. Fix tissues for 16-24 hours at 4 C and rinse thoroughly with DEPC-treated PBS. For whole-mount or large tissue samples only, permeabilize with 50% methanol in DEPC-treated PBS briefly and then 100% methanol at -20 C. Permeabilization time can range from 30 minutes to several months, depending on the size of tissue. Rehydrate by washing with 50% methanol in PBST-DEPC for 5 minutes on a rocker. Repeat with 30% methanol in PBST-DEPC with two final washes in PBST-DEPC for 5 minutes each. Transfer samples to 20% DEPC-treated sucrose, and incubate at 4 C until tissues sink to the bottom. This time can range from 2 hours to overnight. Transfer samples to OCT compound and embed as described previously. If possible, cut sections per slide at 5-10 μm. The steps involved in the preparation of probes, and their application for the detection of specific keratin mRNAs in skin tissue sections, have been described elsewhere (Tong and Coulombe, 2004; Wang et al., 2003).

Srensen`s buffer: Make two stock solutions, 67 mM KH2PO4H2O and 67 mM Na2HPO4 in Milli-Q water; to make a buffer solution of pH 7.2, mix 19.6 ml of 67 mM KH2PO4 and 80.4 ml of 67 mM Na2HPO4. Phosphate buffer (0.1 M): Make two stock solutions, 0.2 M NaH2 PO4H2O and 0.2 M Na2HPO4; for 1 liter of pH 7.2, mix 95 ml of 0.2 M NaH2PO4H2O, 405 ml of 0.2 M Na2HPO4, and 500 ml Milli-Q water. Tris buffer: 8.5 mM Na2HPO4, 3.5 mM KH2PO4, 120 mM NaCl, 41 mM tris(hydroxmethyl)aminomethane; adjust the pH to 7.6. Streptavidin diluent: 0.7% λ-carrageenan (Sigma, Type IV), 0.4% Triton X-100 in Tris buffer. Antibody diluent: 0.7% λ-carrageenan (Type IV), 0.4% Triton X-100, and 3% bovine serum albumin in Tris buffer. Poly-l-lysine (0.1%) for coating slides: 0.1% poly-l-lysine (MW > 300,000; Sigma) in Milli-Q water; aliquot in 1-ml vials; can be stored at -20C for 3-4 months.

3.1 Formaldehyde

Paraformaldehyde 91%is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as paraform`, formagene`, para`, polyoxymethane`). It is slowly formed as a white precipitate by condensation from the predominant species methanediol (formaldehyde hydrate) in solutions of formaldehyde (which may also be called formalin`, formal`, or formalose`) on standing, in an equilibrium (Fig. 3.1). The solution is predominantly of oligomers, but when n becomes large enough the material becomes sufficiently insoluble as to precipitate, when the condensation may still continue. The resulting solid may have n range from ~ 8 to 100, or more. The reaction is driven to the left, to release formaldehyde, by a low concentration of formaldehyde, and accelerated by acidic or alkaline conditions. Solid Paraformaldehyde 91%smells plainly of the monomer (b.p. – 21 C), so it is essentially a convenient means of delivering formaldehyde slowly.

Formaldehyde reacts (as the hydrate) with proteins, cross-linking them, by condensing with secondary amines at the peptide linkage (Fig. 273.5), and with the primary amines at the N-terminal or the side chains of arginine, histidine and lysine residues to create irreversible methylene bridges (Fig. 3.2).[48][49] Similar reactions also occur with the -SH group of cysteine residues, and the amines of DNA and RNA. Whilst such reactions are useful when tissue needs to be fixed for histological work, or simply museum specimens (or cadavers for dissection), clearly they are problematic in living systems. Indeed, formaldehyde is now known variously to be allergenic, generally toxic, extremely cytotoxic, mutagenic and carcinogenic, and so is increasingly under strict control in many contexts. Inhalation of the vapour must be avoided (the vapour pressure is high[50]). It is implicated as an asthma-inducer or exacerbator, and is a major component of house-fire smoke and photochemical smog. The use of paraformaldehyde, therefore, as an ingredient of endodontic cements[51] – to achieve so-called “mummification” (i.e. fixed tissue) – is now considered inappropriate (although not without controversy[52]). The inclusion of alkaline ingredients only serves to accelerate the hydrolysis and depolymerization. Sterilization would, of course, occur anyway. Formaldehyde itself is also used.[53] The acid hydrolysis of hexamethylene tetramine[54] (Fig. 3.3) (solubility in water ~ 850 g/L, 20 C), an ingredient of one known endodontic product,[55] also yields formaldehyde.

Formaldehyde was formerly used as a dentine desensitizing agent, and has even been included in toothpastes (with a pungent taste!) for the same supposed effect, although unsuccessfully.[56][57]

Formaldehyde is also formed as a by-product of free-radical polymerization of methacrylates (as in filled resins) in the presence of oxygen (66),[58] and in this context may be a contributory factor to adverse reactions,[59] being released slowly over a long period, presumably as the peroxides break down. This might also occur with acrylic denture bases as an irritant for denture stomatitis or sore mouth` in addition to residual MMA (52.7).[60] Since the precursor peroxides are not thermally stable, in heat-cured materials these will be decomposed and the resulting formaldehyde may escape, if allowed sufficient time. In cold-cure materials (53), this decomposition will not occur, and the available concentration will therefore be higher. Similar effects will occur in any chemically-similar system, such as so-called “resin-modified” GI cement (98.9).[61][62] This underlines the value of removing the oxygen-inhibited layer wherever possible.

Degradation of cyanoacrylates may proceed through depolymerization by hydrolysis (106.2), by the simple hydrolysis of the ester first, but another reaction occurs that also generates formaldehyde (Fig. 3.4).[63] Again, this may lead to the irritation of living tissue.

There is much concern over human exposure to formaldehyde because of the possibility of adverse reactions, despite the fact that it is present (at a low concentration, generally) in the environment from a number of natural sources as well as being a normal and essential physiological metabolite in man at very low concentrations, where it is not toxic.[64]

Paraformaldehyde: To 1 liter doubly distilled H2O, add 40 g Paraformaldehyde 91%and 12.5 g Na2HPO4 Chromic sulfuric acid: Combine 1800 ml sulfuric acid and 5 ml Chromerge (chromic sulfuric acid cleaning solution, J. T. Baker Chemical Co., Phillipsburg, NJ). Reuse until solution turns green Subbing solution [1% (w/v) gelatin, 0.1% (w/v) chrome alum]: To 1 liter doubly distilled H2O, add 10 g gelatin (heated to dissolve). Then add 1 g chromium potassium sulfate (chrome alum) Mounting solution: Combine 1 ml subbing solution with 9 ml doubly distilled H2O Concentrated (0.25 M) sodium phosphate buffer stock solution: Combine 30 g Na2HPO4 and 5.35 g NaH2PO4 H2O and bring to 1000 ml with doubly distilled H2O. Store refrigerated up to 3 months Sodium phosphate-buffered saline (0.01 M, working solution): Combine 40 ml concentrated sodium phosphate buffer stock, 8.5 g NaCl, and 960 ml doubly distilled H2O. Bring to pH 7.4 with HNO3 or NaOH Boric acid/sodium tetraborate buffer (0.2 M): Bring 0.2 M boric acid (0.62 g in 50 ml doubly distilled H2O) to pH 8.5 with 0.05 M sodium tetraborate (0.95 g sodium tetraborate in 50 ml doubly distilled H2O). Store at room temperature 1-3 months 11.4 mg allantoin 3 ml boric acid/sodium tetraborate buffer, pH 7.5 20.2 mg cupric nitrate 1.2 g silver nitrate 6.4 ml pure pyridine Pour into washed container, wrap in aluminum foil, and place in 40C water bath for 20-30 min before adding slides

Ammoniacal silver: Dissolve 18 g silver nitrate completely in 97.65 ml doubly distilled H2O; add

47.7 ml 0.4% (w/v) sodium hydroxide (NaOH)

4.5 ml acetone

Note: Add just enough ammonia to clear the solution. Ammonia may lose its potency over time, so the precise amount required may vary. This is a critical step since it determines the degree of silver impregnation. Too much ammonia prevents silver impregnation and too little can cause impregnation of normal tissue 7 ml 1% (w/v) citric acid 100 ml 100% (v/v) ethanol 881 ml neutralized doubly distilled H2O Sodium thiosulfate: 250 ml of a 1.0% (w/v) solution Potassium ferricyanide: 250 ml of a 0.5% (w/v) solution Sodium hydroxide: 250 ml of a 0.4% (w/v) solution Citric acid: 250 ml of a 1.0% (w/v) solution Formalin (10%, v/v): Add 2 ml 37% commercial formaldehyde solution to 18 ml doubly distilled H2O

Paraformaldehyde 91% for synthesis. CAS 30525-89-4, chemical formula (CH₂O)n. Paraformaldehyde: Malzeme Gvenlik Bilgi Formu (MSDS) veya SDS, Analiz Sertifikas (COA) ve Kalite Uygunluk Sertifikas (COQ), dosyalar, brorler ve dier dokmanlar. SDSCoA Hill Formula: (CH₂O)n CAS #: 30525-89-4 Chemical Formula: (CH₂O)n 818715 View Pricing & Availability Download Product Safety Card OverviewSupporting DocumentationRelated Products & Applications Overview Replacement Information Description Product Information Applications Physicochemical Information Toxicological Information Safety Information according to GHS Safety Information Storage and Shipping Information Transport Information Specifications Key Spec Table Pricing & Availability Replacement Information Replacement Information In North America 818715.1000 is identical to PX0055-3 but in a different pack size In North America 818715.0100 is identical to PX0055-3 but in a different pack size Key Spec Table CAS # Hill Formula Chemical Formula 30525-89-4 (CH₂O)n (CH₂O)n Pricing & Availability Number Availability Packaging Qty/Pack Price Quantity 8187150100 Contact Customer Service Plastic bottle 100 g Upon Order Completion More Information – Add To Favorites 8187151000 Contact Customer Service Plastic bottle 1 kg Upon Order Completion More Information Add To Favorites Add To Cart Description Catalogue Number 818715 Replaces PX0055-3 Product Information CAS number 30525-89-4 Hill Formula (CH₂O)n Chemical formula (CH₂O)n HS Code 2912 60 00 Structure formula Image Structure formula Image Applications Application Paraformaldehyde 91% for synthesis. CAS 30525-89-4, chemical formula (CH₂O)n. Physicochemical Information Density 1.4 g/cm3 (20 C) Explosion limit 7 – 73 %(V) Ignition temperature 300 C Melting Point 100 – 130 C pH value 5.5 (H₂O, 20 C) (saturated solution) Vapor pressure 1.93 hPa (25 C) Toxicological Information LD 50 oral LD50 Rat 592 mg/kg Safety Information according to GHS Hazard Pictogram(s) Hazard Pictogram(s) Hazard Pictogram(s) Hazard Pictogram(s) Hazard Statement(s) H350: May cause cancer. H302 + H332: Harmful if swallowed or if inhaled. H315: Causes skin irritation. H317: May cause an allergic skin reaction. H318: Causes serious eye damage. H335: May cause respiratory irritation. H341: Suspected of causing genetic defects. Precautionary Statement(s) P201: Obtain special instructions before use. : Wear protective gloves. P280: Wear eye protection. P302 + P352: IF ON SKIN: Wash with plenty of soap and water. P305 + P351 + P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Signal Word Danger

RTECS RV0540000

Storage class 4.1B Flammable solid hazardous materials

WGK WGK 2 obviously hazardous to water

Disposal 3

Relatively unreactive organic reagents should be collected in container A. If halogenated, they should be collected in container B. For solid residues use container C.

Safety Information

Hazard Symbols Hazard SymbolsToxic

Categories of danger harmful, irritant, carcinogenic, sensitizing

R Phrase R 45-20/22-37/38-68-41-43

May cause cancer.Also harmful by inhalation and if swallowed.Irritating to respiratory system and skin.Possible risk of irreversible effects.Risk of serious damage to eyes.May cause sensitisation by skin contact.

S Phrase S 22-26-36/37-45-53

Do not breathe dust.In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.Wear suitable protective clothing and gloves.In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible).Avoid exposure – obtain special instructions before use.

Storage and Shipping Information

Storage Store at

Srensen`s buffer: Make two stock solutions, 67 mM KH2PO4H2O and 67 mM Na2HPO4 in Milli-Q water; to make a buffer solution of pH 7.2, mix 19.6 ml of 67 mM KH2PO4 and 80.4 ml of 67 mM Na2HPO4. Phosphate buffer (0.1 M): Make two stock solutions, 0.2 M NaH2 PO4H2O and 0.2 M Na2HPO4; for 1 liter of pH 7.2, mix 95 ml of 0.2 M NaH2PO4H2O, 405 ml of 0.2 M Na2HPO4, and 500 ml Milli-Q water. Tris buffer: 8.5 mM Na2HPO4, 3.5 mM KH2PO4, 120 mM NaCl, 41 mM tris(hydroxmethyl)aminomethane; adjust the pH to 7.6. Streptavidin diluent: 0.7% λ-carrageenan (Sigma, Type IV), 0.4% Triton X-100 in Tris buffer. Antibody diluent: 0.7% λ-carrageenan (Type IV), 0.4% Triton X-100, and 3% bovine serum albumin in Tris buffer. Poly-l-lysine (0.1%) for coating slides: 0.1% poly-l-lysine (MW > 300,000; Sigma) in Milli-Q water; aliquot in 1-ml vials; can be stored at -20C for 3-4 months.

Paraformaldehyde 91% was formerly used as a dentine desensitizing agent, and has even been included in toothpastes (with a pungent taste!) for the same supposed effect, although unsuccessfully.[56][57]

Paraformaldehyde 91% is also formed as a by-product of free-radical polymerization of methacrylates (as in filled resins) in the presence of oxygen (66),[58] and in this context may be a contributory factor to adverse reactions,[59] being released slowly over a long period, presumably as the peroxides break down. This might also occur with acrylic denture bases as an irritant for denture stomatitis or sore mouth` in addition to residual MMA (52.7).[60] Since the precursor peroxides are not thermally stable, in heat-cured materials these will be decomposed and the resulting Paraformaldehyde 91% may escape, if allowed sufficient time. In cold-cure materials (53), this decomposition will not occur, and the available concentration will therefore be higher. Similar effects will occur in any chemically-similar system, such as so-called “resin-modified” GI cement (98.9).[61][62] This underlines the value of removing the oxygen-inhibited layer wherever possible.

Paraformaldehit 91%

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Paraformaldehit 91%, Para Formaldehit, sv formaldehidin kat halidir. Termoplastik olarak snflandrlan Paraformaldehit 91%, Para Formaldehit bileii, uzun zincirli polioksimetilen glikollerle benzer polimerlerin tipik zelliklerini, yani snmaya maruz kaldklarnda svya dnebilen ve soutma zerine katlaan veya sert, cam benzeri bir malzemeye donanabilen bir zellik sergilemektedir . Aslnda,Paraformaldehit 91% tekrar tekrar eritilir ve soutulabilir ve yine de zelliklerini deimeden muhafaza edebilir.

Paraformaldehit 91% temel olarak bir formalin veya baka bir deyile sulu formaldehitin younlatrlm bir eklidir, neredeyse ayn zelliklere sahiptir. Aslnda Paraformaldehit 91%, para formaldehit, sulu formaldehidin yerini alabilir ve melamin, fenol veya dier reaktif maddelerle kombine edildiinde tahta ve kontrplak retmek iin gerekli olan reineli balayc materyali retebilir. Aslnda, baz avantajlar da vardr. ncelikle, Paraformaldehit 91%, Paraformaldehit 91%i daha byk bir ham rn verimi retmek iin kullanlabilir. kincisi, Paraformaldehit 91%, Para Formaldehit, ileme balamadan nce reaktif maddeden suyun 20 katna kadar uzaklatrlmasn mmkn klar.

Paraformaldehit 91%, ayrca bir aldehit olarak snflandrlr, nk bir karbonil grubu ierir. Paraformaldehit 91%, durumunda, karbon atomu iki hidrojen atomuna balanr. Aldehitler, tarn ve vanilya gibi birok tandk botaniklerin belirgin aromasyla kantland gibi, genellikle gl bir koku verirler. Paraformaldehit 91%, Para Formaldehit bazl solsyonlar, enzimlerin ve bakteriyel replikasyonun paralanmasna bal olarak hcresel bozunmay inhibe edebilen biyolojik sabitleyiciler olarak iyi bilinir. Bu nedenle, formaldehit ve Paraformaldehit 91%, para formaldehit de dahil olmak zere trevleri, doku rneklerini korumak iin kullanlr.

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Paraformaldehit 91% ana endeksleri

Sonu

Beyaz toz ya da prills.

Uygundur

Uymak gerekir.

Uygundur

Erime noktas

135 C ~ 170 C

Uygundur

Kl

% 0.03 maksimum

% 0.01

Asitlik (Formik Asit)

% 0.05 maksimum

0.031%

Fe

Kuru stma Paraformaldehit 91%`den elde edilen formaldehit gaz% 91 yancdr.

Paraformaldehit 91% daha nce bir dentin duyarszlatrma maddesi olarak kullanlmt ve baarsz olmasna ramen ayn szde etki iin di macunlarna (keskin bir tada sahip!) Bile dahil edilmiti. [56] [57]

Paraformaldehit 91%, ayrca bir aldehit olarak snflandrlr, nk bir karbonil grubu ierir. Paraformaldehit 91%, durumunda, karbon atomu iki hidrojen atomuna balanr. Aldehitler, tarn ve vanilya gibi birok tandk botaniklerin belirgin aromasyla kantland gibi, genellikle gl bir koku verirler. Paraformaldehit 91%, Para Formaldehit bazl solsyonlar, enzimlerin ve bakteriyel replikasyonun paralanmasna bal olarak hcresel bozunmay inhibe edebilen biyolojik sabitleyiciler olarak iyi bilinir. Bu nedenle, formaldehit ve Paraformaldehit 91%, para formaldehit de dahil olmak zere trevleri, doku rneklerini korumak iin kullanlr.

Solide poudreux, flocons, blanc odeur de formaldhyde