Citrate Concentrated Solution - Suitable for molecular biology, Ultra pure, 1 M in H2O , CAS No.68-04-2

CAS: 68-04-2 Cat. No.: C433299 Formula: C₆H₅O₇Na₃ Molecular Weight: 258.07 EC Number: 200-675-3

GRADE & PURITY Suitable for molecular biology, Ultra pure, 1 M in H2O

Synonyms

Oracit | Natrocitral | 1,2,3-Propanetricarboxylic acid, 2-hydroxy-, trisodium salt | anhydrous sodium citrate | SODIUM CITRATE (USP IMPURITY) | Sodium citrate,anhydrous | Citrosodina | INS-331(III) | Modified Shohl's Solution | SODIUM CITRATE ANHYDROUS [H

Storage

Room temperature

Shipped In

Normal

Specifications

Synonyms

Oracit | Natrocitral | 1,2,3-Propanetricarboxylic acid, 2-hydroxy-, trisodium salt | anhydrous sodium citrate | SODIUM CITRATE (USP IMPURITY) | Sodium citrate,anhydrous | Citrosodina | INS-331(III) | Modified Shohl's Solution | SODIUM CITRATE ANHYDROUS [H

Specifications & Purity

Suitable for molecular biology, Ultra pure, 1 M in H2O

Storage

Room temperature

Shipped In

Normal

Grade

Suitable for molecular biology, Ultra pure

Names and Identifiers

Canonical Smiles

C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.[Na+].[Na+].[Na+]

IUPAC Name

trisodium;2-hydroxypropane-1,2,3-tricarboxylate

InChIKey

HRXKRNGNAMMEHJ-UHFFFAOYSA-K

INCHI

1S/C6H8O7.3Na/c7-3(8)1-6(13,5(11)12)2-4(9)10;;;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);;;/q;3*+1/p-3

Isomeric SMILES

C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.[Na+].[Na+].[Na+]

Molecular Weight

258.07

Reaxy-Rn

3920956

Reaxys-RN_link_address

https://www.reaxys.com/reaxys/secured/hopinto.do?context=S&query=IDE.XRN=3920956&ln=

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organic acids and derivatives
    • Class Carboxylic acids and derivatives
      • Subclass Tricarboxylic acids and derivatives

• Kingdom: Organic compounds
• Superclass: Organic acids and derivatives
• Class: Carboxylic acids and derivatives
• Subclass: Tricarboxylic acids and derivatives
• Intermediate Tree Nodes: Not available
• Direct Parent: Tricarboxylic acids and derivatives
• Alternative Parents: Tertiary alcohols Carboxylic acid salts Carboxylic acids Organic sodium salts Organic oxides Hydrocarbon derivatives Carbonyl compounds
• Molecular Framework: Aliphatic acyclic compounds
• Substituents: Tricarboxylic acid or derivatives - Tertiary alcohol - Carboxylic acid salt - Organic alkali metal salt - Carboxylic acid - Organic oxygen compound - Organic oxide - Hydrocarbon derivative - Organic sodium salt - Organic salt - Organooxygen compound - Carbonyl group - Alcohol - Aliphatic acyclic compound
• Description: This compound belongs to the class of organic compounds known as tricarboxylic acids and derivatives. These are carboxylic acids containing exactly three carboxyl groups.
• External Descriptors: organic sodium salt

Data sources

1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.

DOI: 10.1186/s13321-016-0174-y

Associated Targets(Human)

CA2 Tclin Carbonic anhydrase II (17698 Activities)

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CA1 Tclin Carbonic anhydrase I (13240 Activities)

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CA5A Tclin Carbonic anhydrase VA (1168 Activities)

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CA9 Tclin Carbonic anhydrase IX (8255 Activities)

Discover Target: CA9

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Associated Targets(non-human)

CA4 Carbonic anhydrase IV (1713 Activities)

Discover Target: CA4

Activity Type	Relation	Activity value	Units	Action Type	Journal	PubMed Id	doi	Assay Aladdin ID

Carbonic anhydrase (69 Activities)

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Mechanisms of Action

Chemical and Physical Properties

• x_melt_point_char: 150 °C (decomposition)
• Molecular Weight: 258.070 g/mol
• Hydrogen Bond Donor Count: 1
• Hydrogen Bond Acceptor Count: 7
• Rotatable Bond Count: 2
• Exact Mass: 257.973 Da
• Monoisotopic Mass: 257.973 Da
• Topological Polar Surface Area: 141.000 Ų
• Heavy Atom Count: 16
• Formal Charge: 0
• Complexity: 211.000
• Isotope Atom Count: 0
• Defined Atom Stereocenter Count: 0
• Undefined Atom Stereocenter Count: 0
• Defined Bond Stereocenter Count: 0
• Undefined Bond Stereocenter Count: 0
• The total count of all stereochemical bonds: 0
• Covalently-Bonded Unit Count: 4

XLogP3

Application Protocols

No item-specific tested application protocols or dilutions are provided in the Product Data. Because this is a concentrated citrate solution, users typically dilute to a defined working buffer per their SOP once the product’s concentration and pH are confirmed via the CoA/Spec Sheet.

General literature-style examples (for context only; not specific to this product):

• IHC antigen retrieval: Dilute stock to 1× citrate buffer at pH ~6.0; heat slides in buffer using a pressure cooker or microwave for 10–20 min; cool gradually and rinse. Optimize time for the antigen/tissue.
• AuNP synthesis: Prepare fresh trisodium citrate solution; add to boiling HAuCl4 under vigorous stirring; maintain boil for several minutes until stable color develops; cool and store.
• Enzyme assay buffer: Prepare citrate buffer at the desired pH within 3–6.5; verify ionic strength and add cofactors/salts as required.

Always adapt conditions to your specific assay, confirm this product’s exact composition, and document any adjustments.

Biological Roles

Contextual biochemical information (literature; not specific to this item’s formulation):

• Central metabolism: Citrate is a key intermediate in the tricarboxylic acid (TCA/Krebs) cycle, formed by condensation of oxaloacetate and acetyl-CoA via citrate synthase. It links carbohydrate, lipid, and amino acid metabolism.
• Metal chelation: The citrate anion forms complexes with divalent/trivalent metal ions (e.g., Ca2+, Mg2+, Fe3+), influencing bioavailability, precipitation, and enzyme activities. This property carries over to laboratory buffer behavior, where citrate can modulate metalloproteins and nucleases.
• pH buffering: As a triprotic acid base pair (citric acid/citrate), the system buffers effectively in acidic to mildly acidic pH ranges. This buffering is exploited in biochemical assays that require controlled proton activity below neutral pH.
• Regulatory roles: In cells, citrate can allosterically regulate enzymes (e.g., phosphofructokinase-1 inhibition, acetyl-CoA carboxylase activation; literature). These regulatory properties are not claims about the product but provide context for why citrate buffers can affect enzyme kinetics in vitro.

Laboratory implications:

• Enzyme assays using citrate should consider both pH and chelation effects.
• For nucleic acid workflows, citrate may suppress metal-dependent degradation pathways but can also affect polymerase/cofactor balance; titrate Mg2+ accordingly.
• Buffer selection should match the biological system’s pH optima and metal requirements.

Buffer Applications

This concentrate is intended for preparing citrate buffer solutions, but the exact concentration and pH are not specified for this item; consult the CoA/Spec Sheet before use.

General guidance (literature/practice):

• Effective pH range: ~3.0–6.5 using mixtures of citric acid and trisodium/disodium citrate. Useful for protein extraction at acidic pH, enzyme assays, immunohistochemistry (IHC) antigen retrieval, and nucleic acid handling where acidic conditions are desired.
• Common working formats:
  • “1× citrate buffer, pH ~6.0” for IHC antigen retrieval (often prepared by diluting a higher-concentration stock and verifying pH).
  • Low-ionic-strength citrate buffers for nuclease control in nucleic acid storage (literature).
• Preparation tips:
  • Adjust pH with citric acid or sodium hydroxide while monitoring temperature (pH is temperature-dependent).
  • Use high-purity water (molecular-biology grade) and filter-sterilize when sterility is required.
  • Validate conductivity/ionic strength when buffer interacts with electrophoretic or binding equilibria.

Compatibility:

• Avoid excessive divalent cations if chelation is undesirable; add Mg2+/Ca2+ back to the target level after buffer preparation when needed.

Important: Do not infer the stock molarity or recommended dilution factor for this specific product from the above. Use the lot-specific documentation.

Green Alternatives

Aqueous citrate buffers are already considered environmentally preferable in many contexts: water is the solvent, citrate is biodegradable, and volatility is negligible. Still, choice of buffer system can impact environmental and process footprints.

Greenness considerations (literature/practice):

• Low VOCs: Water-based, essentially zero vapor emissions compared with organic-buffered systems.
• Biodegradability: Citrate is readily metabolized by microorganisms; downstream wastewater treatment compatibility is generally good (verify pH and metal content before disposal).
• Toxicity: Typically low acute toxicity relative to amine-based or organic solvent systems.

Alternatives and trade-offs (literature):

• Phosphate buffers: Inorganic, low toxicity; strong buffering near neutral pH. Trade-off: potential eutrophication concerns in wastewater; precipitation with Ca2+/Mg2+.
• Acetate buffers: Also aqueous/biodegradable; more volatile (odor), narrower buffering range, weaker metal chelation.
• Good’s buffers (e.g., MES, MOPS): Designed for minimal biological interference but can be more expensive and may not be as biodegradable as citrate.

Mini comparison (qualitative):

• Citrate: Best for pH 3–6.5, strong chelation, high biodegradability.
• Phosphate: Best for pH ~6–8, minimal chelation, nutrient loading risk.
• Acetate: pH ~3.6–5.6, volatile odor, weaker chelation.

Process tips:

• Use only the buffer strength required (avoid over-concentration).
• Reuse/recirculate where purity allows; monitor microbial growth in stored aqueous buffers.

Pharmaceutical Uses

No therapeutic/clinical claims are made. The following are general formulation roles for citrate systems (literature), provided for context in research and manufacturing development only:

• Buffer/excipient: Citrate/citric acid systems are commonly used to control pH in the mildly acidic range in parenteral, oral, and topical formulations during R&D and manufacturing development. They can stabilize pH-sensitive actives and influence solubility profiles.
• Chelating agent: Citrate can sequester trace metals that catalyze oxidative degradation of actives or excipients, improving stability in some formulations. The chelation strength must be balanced to avoid removing essential metal cofactors where relevant.
• Isotonicity contributor: Sodium citrate can contribute to osmolality alongside other salts in aqueous solutions.
• Compatibility: Citrate buffers can interact with aluminum- or calcium-containing components and with cationic polymers/excipients; compatibility studies are essential.
• Processing: Low volatility and high aqueous solubility simplify handling and reduce VOC concerns. Sterile filtration is typically straightforward at working concentrations.

For this item:

• Grade: Suitable for molecular biology; Ultra pure. No pharmacopeial status or endotoxin/specification details are provided. If considering use in formulation development settings, confirm impurities, bioburden/endotoxin, and exact composition via the CoA/Spec Sheet.

Physical Properties

Item-specific physical constants (for this particular concentrated solution) are not provided. Many bulk properties (density, pH, ionic strength) depend on the exact formulation and concentration. Use the CoA/Spec Sheet for precise values.

Item-specific (from Product Data):

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

General/literature values for the common active component (trisodium citrate, anhydrous; for context only):

• Molecular formula: C6H5Na3O7
• Formula weight: ~258.07 g/mol
• Physical form (solid): white to colorless crystalline solid; odorless (literature)
• Melting behavior: decomposes on strong heating rather than distilling (literature)
• Solubility: highly soluble in water; poorly soluble in most organic solvents (literature)
• pKa values of citric acid (for buffer calculations, literature): pKa1 ≈ 3.13, pKa2 ≈ 4.76, pKa3 ≈ 6.40, pKa(OH) ≈ 14.4. Buffering with citrate/citric acid is therefore effective roughly across pH 3–6.5.
• LogP: not applicable to the salt; citrate systems are highly hydrophilic (literature)

Practical notes:

• The viscosity, density, and pH of this concentrated solution will vary with concentration and the acid/base ratio. Do not assume typical “10× citrate buffer” properties; verify with the specific lot documentation.

Quality and Grades

Item-specific quality attributes from Product Data:

• Grade/Purity: Suitable for molecular biology; Ultra pure.

Interpretation and implications:

• Suitable for molecular biology: Indicates preparation under controls intended to minimize nucleases (RNase/DNase), proteases, and common PCR inhibitors. It is appropriate for workflows such as nucleic acid extraction, library preparation buffers, and enzyme storage or reaction buffers—subject to confirmation of composition and pH on the CoA.
• Ultra pure: Suggests high chemical purity with very low inorganic/organic contaminants and particulates, enhancing reproducibility in sensitive assays (e.g., qPCR, NGS sample processing, enzyme kinetics). Exact contaminant limits (metals, UV cutoff, particulates, microbial/endotoxin) are not specified for this item; refer to CoA/Spec Sheet.

What is NOT specified for this item:

• Exact concentration, pH, conductivity/ionic strength, nuclease testing methods/limits, microbial/endotoxin limits, and stabilizers/preservatives. Always review the lot-specific CoA before use in regulated or highly sensitive applications.

Best practices:

• Use clean, nuclease-free technique and containers.
• If diluting to working strength, use molecular-biology-grade water.
• For analytical work (e.g., HPLC/LC–MS), verify UV background and filtration status; pre-filter if necessary (0.22 µm) in a clean environment.

Reaction and Applications

Citrate concentrated solutions are widely used as buffers and chelators across molecular biology and analytical workflows. While item-specific concentration/pH are not specified, the following are common laboratory applications (literature/practice) you can adapt once the product’s CoA is reviewed:

• Buffering in the acidic range: Establishes stable pH in ~3–6.5 for enzyme assays, nucleic acid handling buffers, and protein extraction where acidic conditions are beneficial.
• Metal ion modulation: Citrate chelates Ca2+, Mg2+, Fe3+, and other metals, helping to inhibit metal-dependent nucleases or to prevent scale/precipitation in assays and instruments. Conversely, chelation may suppress essential cofactors; supplement metals if needed.
• Antigen retrieval (IHC/IF): Citrate buffers around pH ~6.0 are commonly used for heat-induced epitope retrieval. The concentrate can be diluted to working strength per your validated protocol (check product CoA first for starting concentration).
• Nanoparticle synthesis and stabilization: In aqueous reductions (e.g., Turkevich method for AuNPs), citrate acts as a reducing agent and capping ligand, controlling particle size and colloidal stability (literature). Use freshly prepared, filtered citrate solutions.
• Electrophoresis/sample prep: Acidic citrate systems can condition gels or serve in sample diluents where phosphate is undesirable.

Practical tips:

• Validate pH and ionic strength after dilution—citrate/citric acid buffer capacity depends strongly on ratio and temperature.
• Degas if bubble formation interferes with optical or microfluidic measurements.
• Filter sterilize (0.22 µm) for cell-free molecular biology workflows if sterility is required and the product is not already sterile (check CoA).

Reaction Conditions

General conditions drawn from the literature for common citrate-enabled processes (not specific to this item; verify composition via the CoA before adopting):

• Gold nanoparticle synthesis (Turkevich–Frens):
  • Solvent: Water.
  • Typical temperature: Reflux (≈100 °C).
  • Reagents: HAuCl4 solution; trisodium citrate solution added rapidly to boiling HAuCl4.
  • Role of citrate: Mild reductant and capping ligand; citrate:Au ratio governs particle size.
  • Time: Color changes over minutes; stir and maintain boil until stable wine-red sol develops.
  • Post-processing: Cool, store in clean glass; ionic strength and pH affect stability.

• Buffering for enzyme assays at acidic pH:
  • Solvent: Water (molecular-biology grade).
  • pH: Choose within ~3–6.5 using citrate/citric acid ratio.
  • Temperature: Typically ambient to 37 °C.
  • Additives: Adjust Mg2+, Ca2+, or other cofactors mindful of citrate chelation.
  • Expected outcomes: Stable pH; potential modulation of metal-dependent enzymes.

• Antigen retrieval (IHC):
  • Working buffer: Commonly citrate buffer pH ~6.0 (literature).
  • Conditions: Heat-induced epitope retrieval via microwave/pressure cooker/water bath; 10–30 min depending on tissue and antigen.
  • Rinse: Allow gradual cooling; rinse in buffer or PBS.

• Metal precipitation control:
  • Conditions: Ambient to heated aqueous media; pH and citrate:metal ratios tune nucleation/growth.

All parameters above are literature guidance. Tailor to your lab’s validated SOPs and the specific composition of this product.

Safety and Handling

GHS classification and detailed hazard data for this specific formulation are not provided in the Product Data. Always consult the SDS for authoritative safety information.

General safety considerations for citrate-based aqueous buffers (literature/practice):

• Hazard profile: Typically low acute toxicity and low hazard, but concentrated alkaline or acidic citrate solutions can be irritating to eyes and skin. Avoid ingestion and inhalation of aerosols.
• PPE: Use standard laboratory PPE—lab coat, safety glasses or splash goggles, and suitable chemical-resistant gloves (e.g., nitrile). When handling large volumes or using heat, employ face/eye protection and appropriate lab ventilation.
• Handling: Avoid contamination; keep container tightly closed. Do not mix with unknown chemicals. If the formulation is alkaline or acidic, neutralize small spills cautiously with appropriate neutralizers and absorbents.
• Incompatibilities (general): Strong acids or bases will shift citrate speciation and pH; strong oxidizers are generally incompatible with organic salts. Metal-sensitive applications may be affected because citrate chelates many metal ions (Ca2+, Mg2+, Fe3+, etc.).
• First aid (overview, not a substitute for SDS):
  • Skin/eye contact: Rinse with water for several minutes; remove contact lenses; seek medical evaluation if irritation persists.
  • Inhalation of mist: Move to fresh air.
  • Ingestion: Rinse mouth; seek medical advice.
• Waste: Aqueous citrate solutions without hazardous contaminants may often be sewer-disposable per institutional rules; verify local regulations and pH limits before disposal.

Solvent Selection

This product is an aqueous citrate concentrate; the functional solvent is water.

General solvent characteristics (literature/practice):

• Polarity: Highly polar, protic medium (water) with citrate as a polycarboxylate counterion system.
• Dielectric environment: High dielectric constant (water ≈78 at 25 °C, literature), supporting dissolution of salts and many hydrophilic biomolecules.
• Miscibility: Fully miscible with water; not miscible with most nonpolar organic solvents. Mixing with water-miscible organics (e.g., lower alcohols) may alter buffer capacity and pH; verify stability before use.

When to choose citrate over alternatives:

• Preferred for buffering in the acidic to mildly acidic range (~pH 3–6.5, literature), where phosphate buffer capacity is poor and acetate may be too volatile or odorous.
• Beneficial where gentle chelation of divalent metals is desired (e.g., to modulate enzyme activity or prevent precipitation). Note that chelation can inhibit metal-dependent enzymes—evaluate assay requirements.

Comparisons (literature):

• Citrate vs phosphate: Citrate is better below pH 6 and chelates metals; phosphate is better near neutral pH and is a stronger metal cofactor in biochemical systems but may precipitate with divalents.
• Citrate vs acetate: Citrate offers broader buffering range and stronger metal binding; acetate is simpler and more volatile, sometimes preferable for downstream removal.

Storage and Reconstitution

Item-specific guidance from Product Data:

• Storage conditions: Room temperature.
• Shipped in: Normal conditions.
• Research use note: For research use only.

Additional handling recommendations (good laboratory practice):

• Keep container tightly capped to prevent evaporation, pH drift, and microbial ingress. Store in a clean, dry area away from direct sunlight and heat sources.
• If sterility is required and not stated on the CoA, consider sterile filtration (0.22 µm) into sterile, nuclease-free containers in a clean environment. Label with lot, date, and any post-processing performed.
• Avoid cross-contamination: Use clean, dedicated pipettes/tips; do not return unused aliquots to the original container.
• Freezing: Many aqueous buffers tolerate refrigeration or freezing, but precipitation and pH shifts can occur depending on composition; because this item’s exact formulation is unspecified, follow the CoA/Spec Sheet or perform a small-scale stability check before freezing.
• Shelf life: Not specified for this item; refer to CoA/Spec Sheet.

Reconstitution:

• This is supplied as a solution; no reconstitution is required. If preparing a working buffer, verify concentration and pH on the CoA and dilute with molecular-biology-grade water to the desired working strength. Recheck pH after dilution and adjust as needed.

Structure and Identity

Overview: This product is a concentrated aqueous citrate solution intended for molecular biology workflows. The buffering/chelating component is typically trisodium citrate (the trisodium salt of citric acid), based on the CAS 68-04-2 association (literature). Item-specific composition/concentration are not provided in the Product Data.

• SKU: C433299
• Product name: Citrate Concentrated Solution
• CAS: 68-04-2 (literature: commonly assigned to trisodium citrate, anhydrous)
• InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
• SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Literature (trisodium citrate, anhydrous): C6H5Na3O7
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
  • Literature (trisodium citrate, anhydrous): ~258.07 g/mol

Structural features (literature, citrate/trisodium citrate):

• Polycarboxylate anion derived from citric acid (a tricarboxylic acid) with one secondary alcohol center (2-hydroxyl) and three carboxylate groups (tri-anionic at neutral-basic pH).
• No stereocenters in the fully deprotonated citrate anion; backbone contains a tertiary carbon bearing the hydroxyl substituent.
• In 2D terms: a propane-1,2,3-tricarboxylate skeleton with a hydroxyl on C2; three terminal carboxylate groups confer high hydrophilicity and metal-chelating ability.

Notes:

• Because this is a solution product, final speciation (citric acid/citrate ratio) and pH depend on the undisclosed formulation. Always consult the CoA/Spec Sheet for the exact composition before quantitative use.

Synthetic Utility

Although primarily used as a biological buffer, citrate solutions have utility in synthetic and materials chemistry (literature/practice):

• Reductant/capping agent: In the Turkevich–Frens method for gold nanoparticle synthesis, trisodium citrate in boiling water reduces HAuCl4 and caps nascent AuNPs, controlling nucleation and growth via citrate–gold surface interactions. Similar roles occur in AgNP preparations.
• Chelation-controlled precipitation: Citrate modulates precipitation of metal hydroxides/oxides or salts (e.g., CaCO3, metal phosphates), enabling size/morphology control in inorganic syntheses.
• Phase and pH control: In aqueous organocatalysis or biocatalysis at acidic pH, citrate buffers maintain proton activity, impacting rates/selectivity of acid-catalyzed hydrolyses and condensations.
• Template/stabilizer: Citrate aids formation of metal–organic or hybrid materials by stabilizing intermediate clusters and preventing uncontrolled aggregation.
• Workup aid: As a chelating wash in extractions, citrate can strip metal catalysts from organic phases into the aqueous layer under controlled pH.

Notes for this item:

• Because concentration and pH are unspecified, calibrate to your target process using the CoA. Rinse and vessel history (residual metals) matter—citrate will complex them and can influence outcomes.
• For colloid syntheses, use freshly prepared, degassed, and filtered citrate solutions to improve reproducibility.

Target Specificity

Not applicable. This product is a chemical/buffer solution, not an affinity reagent or antibody. No antigen/epitope specificity, clone information, or species reactivity applies.