HEPES Sodium -- CAS No: 75277-39-3
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 |
75277-39-3 |
| Name |
HEPES Sodium Salt |
| Synonyms |
4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid sodium salt
N-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt |
| Molecular Formula |
C8H17N2O4SNa |
| Molecular Weight |
260.29 |
| Molecular Structure |
 |
| Test |
H1111, High Purity |
H1113, Ultra Pure |
H1115, Ultra BioPure |
| Appearance |
White powder |
White powder |
White powder |
| Assay (by titration, on dried basis) |
≥ 98.0% |
≥ 99.0% |
≥ 99.0% |
| Solubility (1M solution in H2O) |
Clear, complete and colorless |
Clear, complete and colorless |
Clear, complete and colorless |
| Identification (by IR) |
Conforms to structure |
Conforms to structure |
Conforms to structure |
| Loss on Drying (105°C for 3 hours) |
≤ 3.0% |
≤ 3.0% |
≤ 3.0% |
| pH (1% solution in water) |
9.4 – 11.0 |
9.4 – 11.0 |
9.4 – 11.0 |
| pKa (@ 25ºC) |
-- |
7.4 – 7.7 |
7.4 – 7.7 |
| UV Absorption (0.1M @290nm) |
-- |
≤ 0.05 |
≤ 0.05 |
| UV Absorption (0.1M @280nm) |
-- |
≤ 0.05 |
≤ 0.05 |
| UV Absorption (0.1M @260nm) |
-- |
≤ 0.04 |
≤ 0.04 |
| Insoluble Matter |
-- |
≤ 0.1% |
≤ 0.1% |
| Heavy Metals (Lead) |
-- |
≤ 0.0005% |
≤ 0.0005% |
| Biological Impurity Testing |
| Test |
H1111, High Purity |
H1113, Ultra Pure |
H1115, Ultra BioPure |
| Endotoxin (0.1% solution in H2O) |
-- |
-- |
≤ 0.04 EU/mL |
| Bioburden |
-- |
-- |
≤ 100 CFU/g |
| Trace Impurity Testing |
| test |
H1111, High Purity |
H1113, Ultra Pure |
H1115, Ultra BioPure |
| Iron (Fe) |
-- |
≤ 0.0005% |
≤ 0.0005% |
| Specification Sheet |
| Specification Sheet |
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