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HEPES Buffer
$25.00 AUD
Salts, Buffers & Solutions
HEPES Buffer — ASC-1058
High-Purity Zwitterionic Buffer for Molecular Biology, Cell Culture & Biochemical Research. Australian Stock — same-week dispatch from Melbourne.
🇦🇺 Australian Manufactured ✓ COA Available Molecular Biology Grade pH Range 6.8–8.2 Same-Week Dispatch
Overview
HEPES Buffer (4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid) is a high-purity zwitterionic buffering agent widely used in molecular biology, cell culture, and biochemical research. It is valued for its excellent pH stability in the physiological range and its minimal interaction with biological systems.
HEPES effectively resists pH changes caused by CO₂ exchange and temperature variation, making it particularly suitable for applications where precise and stable pH control is required outside CO₂-controlled incubators. AuSaMicS HEPES Buffer is supplied as a high-quality crystalline powder, manufactured for consistent purity, solubility, and reproducible performance.
Key Features & Benefits
- Stable buffering capacity in the pH range 6.8–8.2
- Zwitterionic structure — minimal biological interference
- Highly soluble in water; rapid dissolution
- Suitable for sensitive biological and biochemical systems
- Reliable batch-to-batch consistency
- CO₂-independent pH stability
- Australian manufactured — quality controlled
- Available in multiple pack sizes for any scale
Chemical & Physical Information
| Chemical Name | 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid |
| Synonyms | HEPES Free Acid; N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid) |
| CAS Number | 7365-45-9 |
| Molecular Formula | C₈H₁₈N₂O₄S |
| Molecular Weight | 238.31 g/mol |
| Appearance | White to off-white crystalline powder |
| Solubility | Freely soluble in water (~500 g/L at 25°C) |
| pKa (25°C) | 7.55 |
| Effective pH Range | 6.8–8.2 |
| Melting Point | ~234–238°C (dec.) |
| Catalogue Number | ASC-1058 |
| Grade | Research / Molecular Biology Grade |
Principle of the Buffer
HEPES is a synthetic zwitterionic buffer of the Good's buffer series, designed to maintain stable pH in biological systems without interfering with enzymatic reactions, ion transport, or cell viability. Its pKa of 7.55 places its buffering optimum squarely in the physiological pH range. Unlike phosphate or carbonate buffers, HEPES buffering capacity is largely independent of CO₂ concentration and temperature fluctuations, providing consistent conditions for cells, enzymes, and biomolecules. The compound does not chelate metal ions significantly, does not penetrate cell membranes readily, and shows negligible light absorption at wavelengths used in UV/visible assays.
Ingredients & Composition
| Component | Concentration / Form | Function | Mechanism |
|---|---|---|---|
| HEPES (Free Acid) | ≥99.0% (as supplied) | Primary buffering agent | Zwitterionic proton donor/acceptor; maintains stable pH 6.8–8.2 via pKa 7.55 equilibrium independent of CO₂ |
Prepared as 1.0 M stock solution: dissolve 238.31 g HEPES in ~800 mL deionised water, adjust pH with NaOH or HCl, bring to 1 L final volume. Filter-sterilise (0.22 µm) for cell culture use.
Comparative Buffer Analysis
| Buffer | pKa (25°C) | Effective pH Range | CO₂ Independent | Cell Culture Suitability | Notes |
|---|---|---|---|---|---|
| HEPES (ASC-1058) | 7.55 | 6.8–8.2 | ✓ Yes | Excellent | Gold standard for CO₂-independent culture |
| PBS (Phosphate) | 7.2 | 5.8–8.0 | ✗ No | Good | Affected by CO₂; may precipitate with Ca²⁺/Mg²⁺ |
| MOPS | 7.2 | 6.5–7.9 | ✓ Yes | Good | Good for electrophoresis; slightly lower pKa than HEPES |
| Bicarbonate | 6.35 | 5.8–8.5 | ✗ No | Good (CO₂ incubator) | Requires CO₂ atmosphere to maintain pH |
| PIPES | 6.8 | 6.1–7.5 | ✓ Yes | Moderate | Lower pH range; slightly less soluble |
| Tricine (ASC-1057) | 8.15 | 7.4–8.8 | ✓ Yes | Good | Higher pH range; used in SDS-PAGE systems |
Pros & Cons Analysis
✓ Advantages
- Excellent pH stability without CO₂ atmosphere
- Zwitterionic — negligible ionic strength contribution
- Minimal UV absorption (transparent above 240 nm)
- Does not chelate divalent metal ions significantly
- High water solubility — easy 1 M stock preparation
- Well-characterised, extensively cited in literature
- Thermally stable over wide temperature range
⚠ Limitations / Considerations
- Can generate toxic radicals under intense UV/visible light
- Not suitable as sole buffer for CO₂-dependent systems
- Slightly more expensive than phosphate buffers
- Some reports of inhibition at very high concentrations (>50 mM)
- Not recommended for applications requiring chelation
Preparation & Use (Typical)
- Weigh the required amount of HEPES powder (e.g. 238.31 g for 1.0 M in 1 L final volume)
- Dissolve in approximately 80% of the final volume of deionised (Milli-Q) water with stirring
- Adjust pH to the desired value (typically 7.0–7.4) using 1 M NaOH or 1 M HCl
- Make up to final volume with deionised water
- Filter-sterilise through a 0.22 µm membrane filter for cell culture applications
- Store at 2–8°C for routine use; aliquot if long-term storage is required
Storage & Stability
🌡 Store in a cool, dry place, protected from moisture and direct sunlight. Keep container tightly sealed after use. Stable for ≥2 years under recommended dry powder storage conditions. Prepared 1 M solutions: store at 2–8°C for up to 6 months or at −20°C for longer periods.
Quality & Documentation
Related Products
Tricine (ASC-1057) · EDTA-Na₂ (ASC-1039) · Sodium Pyruvate (ASC-8016) · KH₂PO₄ (ASC-1043) · Na₂HPO₄ (ASC-1073) · K₂HPO₄ (ASC-8040)
Intended Use: For laboratory research and educational use only. Not for human, animal, veterinary, diagnostic, or therapeutic use. AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au | support@ausamics.com | +61 412 520 598. All information provided in good faith and based on current scientific understanding. Users are responsible for validating suitability for specific applications.
Technical Data Sheet — HEPES Buffer (ASC-1058)
1. Product Identification
| Product Name | HEPES Buffer |
| Catalogue Number | ASC-1058 |
| IUPAC Name | 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid |
| CAS Number | 7365-45-9 |
| Molecular Formula | C₈H₁₈N₂O₄S |
| Molecular Weight | 238.31 g/mol |
| Grade | Research / Molecular Biology Grade |
| Supplier | AuSaMicS Pty Ltd, Thomastown VIC 3074, Australia |
2. Mode of Action
HEPES functions as a zwitterionic proton donor/acceptor with a pKa of 7.55 at 25°C. The piperazine nitrogen accepts/donates protons in the physiological range, while the sulfonate group remains fully ionised across the working pH range. This architecture provides CO₂-independent, thermally stable buffering. HEPES does not participate significantly in enzymatic reactions, does not chelate divalent cations, and shows negligible membrane permeability.
3. Physical & Chemical Properties
| Appearance | White to off-white crystalline powder |
| Odour | Odourless |
| Purity | ≥99.0% (titration) |
| pKa (25°C) | 7.55 |
| Effective pH Range | 6.8–8.2 |
| Solubility in Water | ~500 g/L at 25°C (freely soluble) |
| pH (1% w/v aqueous solution) | ~5.0–6.0 (free acid form) |
| Loss on Drying | ≤0.5% |
| UV Absorbance (240 nm, 1 mg/mL) | ≤0.10 |
| Melting Point | ~234–238°C (decomposition) |
| Density (approx.) | ~1.17 g/cm³ |
4. Quality Control Specifications
| Test Parameter | Method | Specification | Inoculum (CFU) — if applicable |
|---|---|---|---|
| Appearance | Visual | White to off-white crystalline powder | — |
| Purity (titration) | Acid-base titration | ≥99.0% | — |
| Loss on Drying (105°C, 2h) | Gravimetric | ≤0.5% | — |
| pH (1% aqueous solution) | Potentiometry | 5.0–6.0 | — |
| UV Absorbance (240 nm) | Spectrophotometry | ≤0.10 (1 mg/mL) | — |
| Heavy Metals (as Pb) | ICP or colourimetric | ≤10 ppm | — |
| Residue on Ignition | Gravimetric | ≤0.1% | — |
| Solubility test | Visual dissolution | Clear, colourless solution at 10% w/v | — |
5. Preparation of Standard Solutions
| Target Concentration | HEPES (g) per 1 L | pH Adjustment | Notes |
|---|---|---|---|
| 1.0 M stock | 238.31 g | Adjust with 1 M NaOH to desired pH | Filter-sterilise for cell culture |
| 0.5 M stock | 119.15 g | Adjust pH as required | Store at 4°C or −20°C |
| 25 mM working | 5.96 g | Adjust to pH 7.4 | Typical cell culture supplement concentration |
| 10 mM working | 2.38 g | Adjust to pH 7.2–7.4 | Enzyme assay and wash buffer applications |
6. Storage & Stability
Powder: Store at 15–25°C in a tightly sealed container, away from moisture and direct light. Shelf life ≥2 years from manufacture date under recommended conditions.
Prepared solutions (1 M): Stable at 2–8°C for up to 6 months; at −20°C for up to 1 year. Avoid repeated freeze-thaw cycles. Solutions may be filter-sterilised (0.22 µm) and stored in sterile aliquots.
Prepared solutions (1 M): Stable at 2–8°C for up to 6 months; at −20°C for up to 1 year. Avoid repeated freeze-thaw cycles. Solutions may be filter-sterilised (0.22 µm) and stored in sterile aliquots.
7. Literature / References
- Good NE, et al. (1966). Hydrogen ion buffers for biological research. Biochemistry, 5(2):467–477.
- Ferguson WJ, et al. (1980). Hydrogen ion buffers for biological research. Anal Biochem, 104(2):300–310.
- Sigma-Aldrich / Merck (2023). HEPES Product Information Sheet. CAS 7365-45-9.
- Freshney RI (2010). Culture of Animal Cells: A Manual of Basic Technique. 6th ed. Wiley-Blackwell.
- National Center for Biotechnology Information. PubChem Compound Summary for CID 23831. HEPES. https://pubchem.ncbi.nlm.nih.gov/compound/23831
Technical data based on current scientific knowledge and internal quality testing. AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au | +61 412 520 598. For research use only.
Safety Data Sheet — HEPES Buffer (ASC-1058)
Prepared in accordance with the Australian Code for the Labelling of Workplace Hazardous Chemicals and the GHS (Globally Harmonised System). Revision date: 2025.
Section 1 — Identification
| Product Name | HEPES Buffer |
| Catalogue Number | ASC-1058 |
| CAS Number | 7365-45-9 |
| Supplier | AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | +61 412 520 598 | support@ausamics.com |
| Recommended Use | Laboratory buffering agent — research use only |
| Restrictions | Not for human, animal, or therapeutic use |
Section 2 — Hazard Identification
GHS Classification: Not classified as hazardous under the GHS criteria for this formulation at the concentrations supplied.
Signal Word: None | Hazard Statements: None | Precautionary Statements: See Sections 7 & 8.
Signal Word: None | Hazard Statements: None | Precautionary Statements: See Sections 7 & 8.
Section 3 — Composition / Information on Ingredients
| Component | CAS | Molecular Formula | Concentration |
|---|---|---|---|
| 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) | 7365-45-9 | C₈H₁₈N₂O₄S | ≥99.0% |
Section 4 — First Aid Measures
| Inhalation | Remove to fresh air. If symptoms persist, seek medical attention. |
| Skin Contact | Wash thoroughly with soap and water. Remove contaminated clothing. |
| Eye Contact | Rinse immediately with copious water for at least 15 minutes. Seek medical advice if irritation persists. |
| Ingestion | Rinse mouth. Do not induce vomiting. Seek medical advice if large amounts ingested. |
Section 5 — Fire-Fighting Measures
| Flammability | Not flammable under normal conditions |
| Suitable Extinguishing Media | CO₂, dry powder, foam, water spray |
| Special Hazards | Thermal decomposition may produce sulfur oxides (SOₓ) and nitrogen oxides (NOₓ) |
Section 6 — Accidental Release Measures
Sweep up powder. Avoid raising dust. Dispose in accordance with local regulations. Ventilate area. Prevent entry into drains and waterways.
Section 7 — Handling & Storage
| Handling | Use in well-ventilated area. Avoid dust inhalation. Wear appropriate PPE. |
| Storage | Store at 15–25°C in a tightly sealed container. Protect from moisture and light. Keep away from incompatible materials. |
Section 8 — Exposure Controls / Personal Protection
| Exposure Limits | No specific occupational exposure limit established in Australia |
| Respiratory Protection | Dust mask (P1/P2) if dust generation is anticipated |
| Hand Protection | Chemical-resistant gloves (nitrile recommended) |
| Eye Protection | Safety glasses or goggles |
| Skin Protection | Lab coat and closed-toe footwear |
Section 9 — Physical & Chemical Properties
| Appearance | White crystalline powder |
| Odour | Odourless |
| Solubility | Freely soluble in water |
| Melting Point | ~234–238°C (dec.) |
| pH (1% aq.) | ~5.0–6.0 (free acid form) |
Section 10 — Stability & Reactivity
| Stability | Stable under normal conditions |
| Conditions to Avoid | Prolonged exposure to moisture, heat, and strong oxidisers |
| Hazardous Decomposition Products | SOₓ, NOₓ under high-temperature conditions |
Section 11 — Toxicological Information
| Acute Oral Toxicity (rat) | LD₅₀ >5000 mg/kg (low toxicity) |
| Skin/Eye Irritation | Non-irritating at typical laboratory concentrations |
| Carcinogenicity | Not listed as carcinogen (IARC, NTP, OSHA) |
| Reproductive Toxicity | Not classified |
| Phototoxicity | May generate reactive oxygen species under intense UV irradiation — avoid prolonged UV exposure of solutions |
Section 12 — Ecological Information
Not classified as environmentally hazardous. Avoid large-scale release to waterways. Biodegradable.
Section 13 — Disposal Considerations
Dispose in accordance with local regulations. Small laboratory quantities may be disposed via normal waste streams. Do not flush large quantities to sewer.
Section 14 — Transport Information
Not classified as dangerous goods under ADG (Australian Dangerous Goods Code), IATA, or IMDG.
Section 15 — Regulatory Information
Listed on the Australian Inventory of Industrial Chemicals (AIIC). Compliant with the Australian WHS Regulations and the Safe Work Australia Codes of Practice.
Section 16 — Other Information
This SDS was prepared by AuSaMicS Pty Ltd. For research use only. Not for human or animal use. Revision: 2025. Contact: support@ausamics.com
This Safety Data Sheet is provided in good faith and to the best of AuSaMicS's current knowledge. It is the user's responsibility to ensure safe handling, use, and disposal. AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au.
Certificate of Analysis — HEPES Buffer (ASC-1058)
Representative COA. Lot-specific COA available upon request via support@ausamics.com.
| Product Name | HEPES Buffer |
| Catalogue Number | ASC-1058 |
| CAS Number | 7365-45-9 |
| Lot Number | Available on product label |
| Manufacture Date | Available on product label |
| Expiry Date | Available on product label |
| Manufactured by | AuSaMicS Pty Ltd, 31 Longview CT, Thomastown VIC 3074 |
Test Results
| Test | Specification | Result | Status |
|---|---|---|---|
| Appearance | White to off-white crystalline powder | White crystalline powder | ✓ PASS |
| Purity (titration) | ≥99.0% | ≥99.5% | ✓ PASS |
| Loss on Drying | ≤0.5% | ≤0.3% | ✓ PASS |
| pH (1% aqueous solution) | 5.0–6.0 | ~5.4 | ✓ PASS |
| UV Absorbance (240 nm) | ≤0.10 | ≤0.05 | ✓ PASS |
| Heavy Metals (as Pb) | ≤10 ppm | ≤5 ppm | ✓ PASS |
| Residue on Ignition | ≤0.1% | ≤0.05% | ✓ PASS |
| Solubility (10% w/v) | Clear, colourless solution | Clear, colourless | ✓ PASS |
| Identification (IR) | Conforms to reference spectrum | Conforms | ✓ PASS |
Conclusion: This batch of HEPES Buffer (ASC-1058) meets all specified quality criteria and is released for laboratory use. Released by AuSaMicS Quality Control, Thomastown VIC 3074, Australia.
For research use only. AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au | support@ausamics.com | +61 412 520 598.
Applications — HEPES Buffer (ASC-1058)
🧫 Cell Culture
- pH stabilisation for mammalian cell culture media
- Culture systems operated outside CO₂ incubators
- Supplement for DMEM, RPMI, MEM-based media (typically 10–25 mM)
- Hybridoma and suspension cell culture
- Microbial cell culture requiring tight pH control
🔬 Molecular Biology
- Enzyme assay buffers — kinetics, inhibition studies
- Protein purification wash and elution buffers
- Nucleic acid isolation procedures
- In vitro transcription/translation systems
- Electrophoresis running buffers (native PAGE)
🧪 Biochemistry & Research
- Receptor–ligand binding assays
- Immunoprecipitation and co-IP buffers
- Liposome preparation and membrane studies
- Flow cytometry buffer (FACS buffer)
- Western blotting blocking and wash buffers
🏭 Pharmaceutical & QC Labs
- Stability testing media preparation
- Bioassay pH control
- Reference buffer for pH meter calibration checks
- API formulation development studies
🎓 Teaching & Education
- Buffer preparation and pH chemistry practicals
- Enzyme kinetics teaching laboratories
- Cell biology undergraduate experiments
🐠 Aquaculture & Environmental
- Marine and freshwater organism research media
- Oocyte and embryo culture systems
- Environmental toxicology bioassay buffers
Recommended Working Concentration
| Application | Typical HEPES Concentration | Target pH | Notes |
|---|---|---|---|
| Mammalian cell culture media | 10–25 mM | 7.2–7.4 | Supplement to standard culture media |
| Enzyme assay buffer | 20–100 mM | 7.0–7.5 | Depends on enzyme optimum |
| Protein purification | 20–50 mM | 7.4 | Add NaCl for ionic strength adjustment |
| FACS/flow cytometry | 10–25 mM | 7.2–7.4 | Often combined with BSA and EDTA |
| Liposome/membrane studies | 5–50 mM | 7.4 | Compatible with lipid bilayer systems |
| IP / co-IP lysis buffer | 20–50 mM | 7.5 | Include protease inhibitors separately |
Compatible & Related Products
Sodium Chloride · EDTA-Na₂ (ASC-1039) · Sodium Pyruvate (ASC-8016) · Tryptic Soy Broth (AS-1371) · Tricine (ASC-1057) · Potassium Iodide (ASC-1068)
AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au | support@ausamics.com | +61 412 520 598. For research use only.
Cross-Reference / Equivalent Products
The following are equivalent or comparable products from major international suppliers. AuSaMicS ASC-1058 is the Australian-manufactured alternative — same specification, local stock, same-week dispatch.
| Supplier | Product Name | Catalogue Number | Grade / Notes |
|---|---|---|---|
| AuSaMicS 🇦🇺 | HEPES Buffer | ASC-1058 | Research / Mol. Bio. Grade — Australian made, same-week dispatch |
| Sigma-Aldrich / Merck | HEPES | H3375, H4034, H7523 | Cell culture grade, BioReagent, >99.5% |
| Thermo Fisher Scientific | HEPES Free Acid | BP310, J61275 | ACS grade and BioReagent options available |
| Gibco / Thermo Fisher | HEPES Solution (1 M) | 15630080, 15630106 | Ready-to-use 1 M sterile solution for cell culture |
| BD Biosciences | HEPES Buffer | Various | Research grade |
| Bioworld | HEPES Free Acid | 40520006 | Research grade, >99% |
| AppliChem / ITW Reagents | HEPES | A1069 | Biochemistry grade |
| VWR / Avantor | HEPES | 0511, J63059 | Multiple grades available |
| Astral Scientific (AU) | HEPES | Various | Research grade, imported |
⚠ Note: Catalogue numbers and specifications may change. Always verify current supplier information before ordering. AuSaMicS products are manufactured in Australia and meet equivalent research-grade specifications. For cell culture applications, use only filter-sterilised solutions prepared from research-grade powder.
Why Choose AuSaMicS?
- Australian manufactured — local quality control
- Same-week dispatch from Melbourne
- Competitive pricing — no import delays
- Full documentation: COA, SDS, TDS
- Direct technical support from the formulator
- Multiple pack sizes — from 10 g to 1 kg
Intent-Based Search Queries
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Cross-reference data provided for informational purposes only. Trademark names belong to their respective owners. AuSaMicS Pty Ltd | 31 Longview CT, Thomastown VIC 3074 | ABN: 56 676 640 467 | www.ausamics.com.au | support@ausamics.com | +61 412 520 598. For research use only.