Saturated Ammonium Sulfate Solution (SAS) - BioReagent, Ready-to-use, Suitable for electrophoresis, for Protein analysis, pH 7.0 - 7.2 , CAS No.7783-20-2

CAS: 7783-20-2 Cat. No.: S1528792 Formula: (NH₄)₂SO₄ Molecular Weight: 132.14 EC Number: 231-984-1

GRADE & PURITY BioReagent, Ready-to-use, Suitable for electrophoresis, for Protein analysis

Storage

Room temperature

Shipped In

Normal

Application

Protein Separation and Purification

Overview

Protocol (for reference only):Saturated ammonium sulfate solution (SAS), prepared from ammonium sulfate (CAS: 7783-20-2, molecular weight: 132.14, chemical formula: (NH₄)₂SO₄), is a common precipitant widely used in ammonium sulfate salting-out for protein isolation and purification.

Salting-out principle: Ammonium and sulfate ions dissociated from high-concentration ammonium sulfate competitively bind water molecules, disrupting the hydration shell on protein surfaces, reducing protein solubility and causing target proteins to precipitate out of the solution.

Usage recommendations: The solubility of ammonium sulfate in water changes relatively gradually with temperature, which is an advantage of its use as a salting-out reagent; however, the actual saturation level of a saturated ammonium sulfate solution may still vary slightly with temperature, and crystals may precipitate during low-temperature storage. Before use, it is recommended to warm the solution back to room temperature, confirm that it remains saturated, re-measure the pH, and adjust as needed.

Protocol (for reference only):

Follow the specific experimental requirements.

Precautions:

1.For your safety and health, please wear a lab coat and disposable gloves during operation.

2.For research use only. Not for clinical use.

Specifications

Specifications & Purity

BioReagent, Ready-to-use, Suitable for electrophoresis, for Protein analysis

Stability And Storage

Store at RT long term (12 months).

Storage

Room temperature

Shipped In

Normal

Grade

BioReagent, for Protein analysis, Ready-to-use, Suitable for electrophoresis

Product Line

Biological Products

Names and Identifiers

Isomeric SMILES

[NH4+].[NH4+].[O-]S(=O)(=O)[O-]

WGK Germany

1

RTECS

BS4500000

Molecular Weight

132.14

Reaxy-Rn

11343144

Reaxys-RN_link_address

https://www.reaxys.com/reaxys/secured/hopinto.do?context=S&query=IDE.XRN=11343144&ln=

Chemical and Physical Properties

• Melt Point(°C): >280 °C

Application Protocols

No manufacturer-validated application protocols are provided for this item. For general guidance on using saturated ammonium sulfate for protein precipitation and related workflows, refer to the Reaction Conditions section and standard biochemical literature. Always optimize parameters (temperature, % saturation, equilibration time) for your specific sample.

Biological Roles

This product is a tool reagent; it does not have intrinsic biological activity beyond physicochemical effects. The solute, ammonium sulfate, exerts characteristic effects on biomacromolecules via ionic strength and kosmotropicity.

• Kosmotropic salt behavior (literature): Sulfate is strongly kosmotropic in the Hofmeister series, promoting water structuring and favoring hydrophobic interactions. This reduces protein solubility at high concentrations (salting-out), while at lower concentrations it can stabilize some folded states.
• Protein precipitation/selectivity: Different proteins display distinct precipitation thresholds as a function of % ammonium sulfate saturation, temperature, and pH—enabling fractionation.
• Enzyme handling: Many enzymes withstand transient exposure to high ammonium sulfate; some may be stored as ammonium sulfate suspensions with retained activity after re-dissolution (must be validated empirically for each enzyme).
• Nucleic acids and complexes: High ionic strength can shield electrostatic repulsion, influencing assembly/disassembly of ribonucleoproteins and altering phase behavior of biomolecular condensates.
• Microbial considerations: Elevated salinity reduces growth of many microbes, which can be beneficial for short-term sample preservation; this is not a sterilant and should not be relied upon for asepsis.

Caveats:

• Downstream assays (e.g., spectrophotometry, enzyme kinetics) can be perturbed by high sulfate/ammonium; thorough desalting/buffer exchange is recommended prior to analysis.
• pH shifts with temperature and dilution can affect biomolecule charge and precipitation behavior.

Buffer Applications

Saturated ammonium sulfate solution is not used as a buffering system in the classical sense (it has limited buffering capacity near neutral pH). Its primary role is as a salting-out agent.

Practical, related uses (literature/practice):

• Protein precipitation media: Use SAS to reach defined % saturation by combining with the sample in calculated ratios. Maintain temperature consistency to ensure reproducible cut points.
• Conductivity/ionic strength adjustment: SAS can set very high ionic strength for specific extraction protocols (e.g., disrupting weak protein–ligand interactions).
• Post-precipitation handling: Pellets are typically re-dissolved in the desired true buffer (e.g., Tris-HCl, phosphate, HEPES) followed by desalting to restore physiological ionic strength.

Notes:

• If buffering is required during precipitation, perform the precipitation in the presence of a compatible buffer system (e.g., 20–50 mM phosphate or Tris) and then titrate pH after desalting as needed.
• Avoid buffers with components that form insoluble salts with sulfate at high concentrations (most common biological buffers are compatible, but assess solubility and ionic competition for your system).

For recipes/conversions (general guidance):

• Many laboratories reference empirically derived tables to convert density/refractive index of ammonium sulfate solutions to "% saturation" at a defined temperature (often 0–4 °C or 20–25 °C). Use such tables to plan stepwise fractionations. These are literature tools, not item specifications.

Green Alternatives

From a green chemistry perspective, SAS is often preferable to organic solvent precipitation and can reduce reliance on flammable, volatile organics.

Comparison (general; not item-specific):

• SAS (ammonium sulfate):
  • Pros: Aqueous, nonflammable, inexpensive, broadly available; effective, selective precipitation; easy re-dissolution of pellets; relatively benign environmental profile when managed properly.
  • Cons: Generates high-salt waste requiring disposal; desalting step needed; temperature-dependent behavior.
• Organic solvent precipitation (acetone/ethanol):
  • Pros: Rapid, low-temperature precipitation; volatile solvents can be removed by evaporation.
  • Cons: Flammable, VOC emissions, refrigeration demands, potential protein denaturation.
• PEG precipitation:
  • Pros: Mild, non-ionic; often good for viruses/nucleic acids.
  • Cons: Polymer waste; more challenging removal; viscosity can impede processing.
• Ammonium acetate (concentrated, aqueous):
  • Pros: Volatile salt—easier to remove by lyophilization.
  • Cons: Different selectivity; buffering effects; odor of ammonia upon basification.

Greener practice tips:

• Optimize cut points to minimize reagent use and waste volume.
• Reuse cold baths and employ closed containers to reduce aerosol formation.
• Desalt using low-waste methods (e.g., high-capacity gel filtration) and segregate saline waste for appropriate treatment.
• Document energy impacts of cooling/heating; perform at ambient temperature when compatible with protein stability.

Pharmaceutical Uses

This product is designated For research use only and is not intended for human or veterinary applications.

Contextual, non-clinical uses (literature/industry practice):

• Bioprocess development: Ammonium sulfate precipitation is used at process development and sometimes manufacturing scale for capture/clarification of proteins before chromatographic polishing. SAS can serve as a stock solution to rapidly reach target % saturation during screening.
• Excipient considerations: While ammonium sulfate can appear as a processing aid in upstream steps, it is generally removed prior to final formulation; it is not a typical excipient in finished drug products.
• Regulatory context: Specifications for process reagents (bioburden, endotoxin, trace metals) are defined per process control strategies; none are specified here for this catalog item. Any use in GMP settings would require supplier qualification and lot-specific documentation (CoA), followed by validated removal downstream.

Practical notes:

• Downstream clearance: Validate desalting/diafiltration to acceptable residual ammonium and sulfate levels per process requirements.
• Analytics: Monitor conductivity, osmolality, and residual ions (e.g., by ion chromatography) after removal steps.

Reminder: No therapeutic claims are made or implied. This reagent is for laboratory research and process development only.

Physical Properties

Item-specific numerical specifications are not provided in the product data and may vary by lot and preparation temperature.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Concentration, pH, conductivity, density: Not specified for this item; refer to CoA/Spec Sheet.
• Storage conditions: Room temperature (per Product Data).

Literature/general properties for saturated ammonium sulfate solutions (for context only; not item specifications):

• Solubility of ammonium sulfate in water: increases with temperature; at 25 °C, saturation is commonly cited near ~3.9–4.1 M, corresponding to roughly 50–60% w/w, depending on reference and temperature control.
• pH (25 °C): typically mildly acidic, often ~5.0–6.0 for concentrated solutions due to ammonium acid–base equilibria.
• Density (25 °C): increases with salt content; saturated solutions are roughly in the 1.20–1.30 g/mL range depending on exact concentration and temperature.
• Refractive index: rises steeply with concentration; often used for concentration checks in bioprocess labs (values are concentration- and temperature-dependent; consult refractometric tables).
• Freezing/boiling behavior: high ionic strength depresses freezing point and elevates boiling point (colligative effects); solutions can crystallize salt upon cooling and re-dissolve upon warming with agitation.
• Miscibility: Fully miscible with water; mixing with miscible organic solvents (e.g., ethanol, acetone) can reduce salt solubility and induce precipitation of salt and/or biomolecules.

Always verify lot-specific parameters on the CoA before critical use.

Quality & Grades

• Item grade: BioReagent (per Product Data).

What BioReagent grade generally implies (literature/industry practice; not a specification):

• Intended for laboratory research and biochemical workflows (e.g., protein fractionation, enzyme handling).
• Typically controlled for parameters important to biomolecule handling such as low organic contaminants and consistent ionic strength behavior; however, exact limits (e.g., heavy metals, UV absorbance, endotoxin, nuclease activity) are product- and lot-specific.

Item-specific notes:

• Stabilizers/preservatives: Not specified for this item; refer to CoA/Spec Sheet.
• pH and concentration tolerances: Not specified for this item; refer to CoA/Spec Sheet.
• Appearance/clarity/particulates: Not specified for this item; refer to CoA/Spec Sheet.

Best practices for quality assurance in use:

• Verify lot-specific concentration (e.g., by density, refractive index, or conductivity) when precise saturation levels are critical to precipitation cut points.
• Record temperature at time of use; ammonium sulfate solubility is temperature-dependent, affecting “% saturation.”
• If sterility is required (e.g., for sensitive protein work), filter through 0.22 μm under aseptic conditions; autoclaving can change concentration via evaporation—validate post-sterilization.

Documentation:

• For exact assay/purity and any biological contaminant controls, consult the CoA/Spec Sheet for SKU S1528792.

Reaction & Applications

Primary application domain: biomolecule handling rather than small-molecule synthesis. Saturated ammonium sulfate solution (SAS) is a workhorse reagent for protein chemistry.

Key uses (literature/practice):

• Protein fractionation by salting-out: Stepwise addition of SAS to crude lysates or serum enables selective precipitation at defined % saturation (e.g., 20–40%, 40–60%, etc.), enriching target proteins by differential solubility.
• Enzyme concentration and stabilization: Many enzymes retain activity after precipitation and can be stored as ammonium sulfate slurries; high salt suppresses proteases and microbial growth (verify for your enzyme).
• Removal of nucleic acids and lipids: Precipitation can reduce polyanion content; follow with dialysis/desalting.
• Immunoglobulin preparation: IgG often precipitates around 33–50% saturation at 0–4 °C (ranges are antibody- and species-dependent; optimize empirically).
• Sample cleanup prior to chromatography: Salting-out to reduce volume/complexity, then buffer exchange into starting mobile phase.

Practical tips:

• Define and maintain temperature; ammonium sulfate solubility changes with °C, shifting % saturation cut points.
• Add SAS slowly with stirring to avoid local supersaturation and protein aggregation; measure conductivity or density to confirm target saturation.
• Allow equilibration (typically 15–60 min) before pelleting at appropriate g-force; keep cold for labile proteins.
• Desalt thoroughly (dialysis, spin columns, gel filtration) before assays sensitive to ionic strength.
• Filtration of SAS through 0.22 μm improves clarity/bioburden control; avoid autoclave evaporation or re-verify concentration after heat.

Reaction Conditions

Guidance below reflects typical literature practice for protein precipitation with ammonium sulfate; these are not specifications for this item.

General protein salting-out workflow (example guidance):

• Temperature: 0–4 °C for labile proteins; 20–25 °C for robust proteins. Maintain constant temperature throughout each precipitation step.
• Target saturation: Choose empirically (e.g., 20–40% to remove highly hydrophobic proteins; 40–60% for many globular proteins; values are protein-dependent). Use published tables to translate target % saturation into volumes of SAS versus sample at your working temperature.
• Addition: Add SAS slowly with gentle stirring to avoid local supersaturation. Confirm progress by monitoring density, refractive index, or conductivity.
• Equilibration: 15–60 min after reaching target saturation; some proteins require longer for complete precipitation.
• Centrifugation: 10–20 min at 10,000–20,000 × g (typical lab practice) at the working temperature to pellet the precipitate. Adjust g-force/time based on rotor and sample volume.
• Wash (optional): Briefly resuspend pellet in a lower-salt buffer containing a defined % ammonium sulfate to remove co-precipitants; re-pellet.
• Re-dissolution: Dissolve pellet in minimal desired buffer (e.g., 20–50 mM Tris-HCl, pH 7.5). Remove salt by dialysis, gel filtration, or spin desalting.

Quantitation aids:

• Use density or Brix/refractive index to verify solution concentration; consult ammonium sulfate concentration tables at your temperature.
• Record temperature and volumes meticulously for reproducibility.

Always validate conditions for each target protein and downstream assay.

Safety & Handling

GHS/SDS information specific to this item is not provided here. Always consult the supplier SDS for authoritative hazard classification and response measures.

• GHS classification, pictograms, signal word, H-statements: Not specified for this item; refer to SDS.

General safety considerations for concentrated ammonium sulfate solutions (literature/practice):

• Hazards: Typically considered of low acute toxicity, but concentrated salt solutions may be irritating to eyes/skin and harmful if ingested in large amounts. May cause respiratory irritation as aerosols/mists.
• PPE: Wear lab coat, appropriate chemical-resistant gloves (e.g., nitrile), safety glasses or face shield for splash risk. Use in a well-ventilated area.
• Spill response: Contain, dilute with water if appropriate, and collect for disposal. Salt residues are slippery; rinse thoroughly to avoid slip hazards.
• Incompatibilities: Strong bases can liberate ammonia; strong acids can alter pH and corrosivity. Avoid contact with reactive oxidizers. Mixing with alcohols/acetone may salt-out proteins and precipitate solids, potentially clogging drains.
• Peroxide formation: Not applicable (aqueous inorganic salt solution).
• First aid (general):
  • Skin/eye contact: Rinse with water for several minutes; remove contaminated clothing; seek medical attention if irritation persists.
  • Inhalation: Move to fresh air; obtain medical advice if symptoms occur.
  • Ingestion: Rinse mouth; do not induce vomiting; seek medical advice.
• Disposal: Follow institutional and local regulations. High-salt waste may require segregation; avoid discharge to environments sensitive to salinity.

Note: For research use only (per Product Data).

Solvent Selection

This product is an aqueous, high-ionic-strength medium, not an organic solvent. Solvent selection considerations revolve around its compatibility and intended effect (salting-out) in aqueous biochemistry.

• Polarity/medium: Strongly polar, fully water-based; very high ionic strength due to dissolved (NH4)2SO4.
• Miscibility: Fully miscible with water. Addition to aqueous protein solutions increases ionic strength and relative hydrophobicity of the medium, promoting protein precipitation. Mixing with miscible organics (ethanol, acetone, isopropanol) reduces salt solubility and can co-precipitate salts/proteins.
• Dielectric environment (literature): Ionic strength markedly lowers effective dielectric constant of the aqueous phase experienced by proteins, favoring hydrophobic interactions.

When to choose SAS vs. alternatives (general):

• Choose SAS for classical protein fractionation, enzyme stabilization at high salt, and removal of proteases by selective precipitation. It is cost-effective, gentle, and reversible (pellets re-dissolve easily on desalting).
• Alternatives:
  • Polyethylene glycol (PEG) precipitation: Often milder for nucleic acids or viruses; less ionic stress but can be harder to remove completely.
  • Organic solvent precipitation (acetone, ethanol): Rapid precipitation at low temperature; harsher on delicate proteins; flammable and less green.
  • Sodium sulfate or ammonium acetate: Different selectivity and volatility (ammonium acetate is volatile, useful when salt removal must be facile by lyophilization).

Selection tips:

• Control temperature rigorously; define “% saturation” at a specified °C.
• Avoid introducing chelators/detergents unless their effect on precipitation has been validated.

Storage & Reconstitution

• Storage conditions (item-specific): Room temperature (per Product Data). Store tightly capped to minimize evaporation, which can change concentration. Protect from contamination; for sensitive work, consider aseptic technique and 0.22 μm filtration upon first opening.

• Shipping: Shipped under normal conditions (per Product Data).

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.

• Reconstitution: Not applicable; supplied as a ready-to-use solution. If salt crystallization occurs during cold storage or evaporation, warm to room temperature and mix until fully dissolved; verify concentration (e.g., by density or refractive index) before critical use.

• Stability considerations (general):

  • Temperature dependence: Concentration drifts with evaporation and with crystallization upon cooling; maintain consistent temperature during use.
  • Microbial growth: High ionic strength inhibits many microbes but is not a guarantee of sterility. For long-term storage after opening, clean technique and, if compatible with use, addition of a sterile filtration step are recommended.
  • Container compatibility: Use corrosion-resistant caps/closures; sulfate solutions are compatible with most lab plastics and glass.

• Documentation: For any lot-specific shelf life, pH, and concentration tolerances, consult the CoA/Spec Sheet.

Note: For research use only.

Structure & Identity

Aqueous, high-ionic-strength precipitation medium prepared as a saturated solution of ammonium sulfate in water (commonly abbreviated “SAS”). Item is a solution rather than a single-component neat compound.

• Item-specific identifiers (this SKU):

  • SKU: S1528792
  • Product name: Saturated Ammonium Sulfate Solution (SAS)
  • Grade: BioReagent
  • CAS, InChIKey, SMILES: Not specified for this item; refer to CoA/Spec Sheet.

• Solute identity (literature/general):

  • Name: Ammonium sulfate
  • Molecular formula: (NH4)2SO4 (literature)
  • Molecular weight: 132.14 g/mol (literature)
  • SMILES/InChIKey (for solute): literature identifiers exist for ammonium sulfate, but are not item specifications; consult standard databases if needed.

• Structural features (solute; literature):

  • Inorganic salt composed of two ammonium cations and one sulfate dianion.
  • Functional “groups”: quaternary-like ammonium centers (protonated ammonia) and tetrahedral sulfate (SO4 2−) with S–O bonds of predominantly ionic character in solution.

• 2D structural description (solute; literature):

  • Discrete NH4+ ions hydrogen-bonded to water and charge-balanced with SO4 2−; no covalent network in solution. The saturated solution contains solvated ions at or near their solubility limit at the preparation temperature.

Notes:

• This is a formulated aqueous solution; precise concentration, pH, conductivity, and density are product-specific and not listed here. Use the CoA for exact identity and lot-specific parameters.

Synthetic Utility

Although primarily a biochemical reagent, saturated ammonium sulfate solution has niche uses in synthetic and analytical chemistry where strong ionic strength or sulfate counterions are advantageous.

Potential utilities (literature/general):

• Phase manipulation and extractions: High-salt aqueous phases can “salt out” certain organics, improving liquid–liquid extraction efficiency (salting-out effect) by reducing solubility of nonpolar/weakly polar solutes in water.
• Ion pairing and crystallization: Sulfate provides a divalent anion that can drive precipitation of cationic species as sulfates from aqueous media; SAS allows rapid generation of supersaturation on mixing.
• Protein conjugation workflows: As a preparative step before covalent modifications, SAS precipitation can concentrate and desalt proteins (after re-dissolution and buffer exchange), indirectly enabling more controlled bioconjugation reactions.
• Analytical cleanup: Removal of proteins from biological matrices by precipitation prior to small-molecule analysis.

Caveats:

• For small-molecule synthesis, the presence of high ammonium and sulfate concentrations can interfere with catalysts or sensitive functional groups; typically, one would avoid introducing SAS unless the mechanism benefits from strong salting-out.
• pH control is limited; use separate buffers for reactions requiring tight pH regulation.

If exploiting salting-out effects, quantify ionic strength and temperature rigorously; use density or refractive index correlations (literature) to reproduce conditions.

Target Specificity

Not applicable. This product is a chemical reagent (saturated ammonium sulfate solution) and does not have antigen/epitope specificity, clone, isotype, or species reactivity. No target-specific data are provided for this item.