HEPES -- CAS No: 7365-45-9
HEPES has been described
as one of the best all-purpose buffers available
for biological research.1 Similar to many amino
acids, HEPES is zwitterionic at most biological
pHs. It's effective as a buffer in the pH range of
6.8 to 8.2, and in concentrations between 10
millimolar to 25 millimolar. HEPES is one of the
most effective buffers in the important physiological
pH range of 7.2 to 7.6. HEPES has been
utilized extensively for research and commercial
applications in the cell culture and tissue culture
industries. Other large application areas include
cosmetics and skin care, electronics and
computer chip manufacturing.
1 N.E. Good, et al., Biochemistry, 5, 467 (1966).
| CAS Registry Number |
7365-45-9 |
| Name |
HEPES |
| Synonyms |
4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid; N-2-Hydroxyethylpiperazine-N'-2-ethanesulfonic acid; 2-[4-(2-Hydroxyethyl)-1-piperazine]ethanesulfonic acid |
| Molecular Formula |
C8H18N2O4S |
| Molecular Weight |
238.30 |
| Molecular Structure |
 |
| Test |
H1108, High Purity |
H1104, Ultra Pure |
H1107, Ultra Biopure |
H1101, Low Metals |
| Price |
|
|
|
|
| Appearance |
White crysatlline powder |
White crystalline powder |
White crystalline powder |
White crystalline powder |
| Assay (by titration, on dried basis) |
NLT 99.0% |
NLT 99.5% |
NLT 99.5% |
NLT 99.5% |
| Solubility (1M solution in H2O) |
Clear, complete and colorless |
Clear, complete and colorless |
Clear, complete and colorless |
Clear, complete and colorless |
| Identification (by IR) |
Acceptable |
Conforms to structure |
Conforms to structure |
Conforms to structure |
| Melting Point |
-- |
-- |
-- |
-- |
| Water (105°C for 3 hours) |
≤ 1.0% |
≤ 1.0% |
≤ 1.0% |
≤ 1.0% |
| Water (KF) |
-- |
≤ 0.5% |
≤ 0.5% |
≤ 0.1% |
| pH (5% solution in water) |
5.0 – 6.5 |
5.0 – 6.5 |
5.0 – 6.5 |
5.0 – 6.5 |
| pKa (@25°C) |
7.45 – 7.65 |
7.45 – 7.65 |
7.45 – 7.65 |
7.45 – 7.65 |
| UV Absorption (1M @290nm) |
-- |
≤ 0.04 |
≤ 0.04 |
≤ 0.04 |
| UV Absorption (1M @280nm) |
-- |
≤ 0.04 |
≤ 0.05 |
≤ 0.05 |
| UV Absorption (1M @260nm) |
-- |
≤ 0.05 |
≤ 0.05 |
≤ 0.05 |
| Residue on Ignition |
-- |
≤ 0.1% |
≤ 0.1% |
≤ 0.1% |
| Insoluble Matter |
-- |
-- |
-- |
-- |
| Heavy Metals (Lead) |
≤ 0.0005% |
≤ 0.0005% |
≤ 0.0005% |
≤ 0.0005% |
| Biological Impurity Testing |
| Test |
H1108, High Purity |
H1104, Ultra Pure |
H1107, Ultra Biopure |
H1101, Low Metals |
| Endotoxin |
-- |
-- |
NMT 0.1 EU/mg |
-- |
| Endotoxin (0.2% solution in H2O |
-- |
-- |
≤ 0.10 EU/mL |
-- |
| Bioburden |
-- |
-- |
NMT 100 CFU/g |
-- |
| RNase, DNase, Nickase, Protease |
-- |
-- |
None detected |
-- |
| Cell culture test |
-- |
-- |
Pass |
-- |
| Trace Impurity Testing |
| Test |
H1108, High Purity |
H1104, Ultra Pure |
H1107, Ultra Biopure |
H1101, Low Metals |
| Aluminum (Al) |
-- |
-- |
-- |
≤ 0.0005% |
| Arsenic (As) |
-- |
-- |
-- |
≤ 0.0001% |
| Barium (Ba) |
-- |
-- |
-- |
≤ 0.0005% |
| Bismuth (Bi) |
-- |
-- |
-- |
≤ 0.0005% |
| Cadmium (Cd) |
-- |
-- |
-- |
≤ 0.0005% |
| Calcium (Ca) |
-- |
-- |
-- |
≤ 0.001% |
| Chloride (Cl) |
-- |
-- |
-- |
≤ 0.05% |
| Chromium (Cr) |
-- |
-- |
-- |
≤ 0.0005% |
| Cobalt (Co) |
-- |
-- |
-- |
≤ 0.0005% |
| Copper (Cu) |
-- |
-- |
-- |
≤ 0.0005% |
| Iron (fe) |
≤ 0.0005% |
≤ 0.0005% |
≤ 0.0005% |
≤ 0.0005% |
| Lithium (Li) |
-- |
-- |
-- |
≤ 0.0005% |
| Magnesium (Mg) |
-- |
-- |
-- |
≤ 0.0005% |
| Manganese (Mn) |
-- |
-- |
-- |
≤ 0.0005% |
| Molybdenium (Mo) |
-- |
-- |
-- |
≤ 0.0005% |
| Nickel (Ni) |
-- |
-- |
-- |
≤ 0.0005% |
| Potassium (K) |
-- |
-- |
-- |
≤ 0.05% |
| Sodium (Na) |
-- |
-- |
-- |
≤ 0.05% |
| Strontium (Sr) |
-- |
-- |
-- |
≤ 0.0005% |
| Zinc (Zn) |
-- |
-- |
-- |
≤ 0.0005% |
| Sulfate (S04) |
≤ 0.05% |
≤ 0.05% |
≤ 0.05% |
≤ 0.05% |
| Specification Sheet |
| Specification Sheet |
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