Merck
All Photos(1)

391338

Millipore

HEPES, Free Acid, ULTROL® Grade

A zwitterionic N-substituted aminosulfonic acid buffer. Useful in the pH 6.8-8.2 range. Has a pKa of 7.48 at 25°C. Absorbance (1.0 M, H2O, 260 nm):≤0.05.

Synonym(s):
N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid), N-2-Hydroxyethylpiperazine-Nʹ-2-ethanesulfonic Acid, 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid, HEPES
Empirical Formula (Hill Notation):
C8H18N2O4S
CAS Number:
Molecular Weight:
238.30
Beilstein:
883043
MDL number:

Quality Level

assay

≥99% dry basis (titration)

form

crystalline powder

manufacturer/tradename

Calbiochem®

storage condition

OK to freeze

color

white

useful pH range

6.8-8.2

pKa (25 °C)

7.5

solubility

water: 1 M

anion traces

chloride (Cl-): ≤0.01%
sulfate (SO42-): ≤0.05%

cation traces

Na: ≤0.1%
heavy metals: ≤1 ppm

shipped in

ambient

storage temp.

15-25°C

SMILES string

OCCN1CCN(CC1)CCS(O)(=O)=O

InChI

1S/C8H18N2O4S/c11-7-5-9-1-3-10(4-2-9)6-8-15(12,13)14/h11H,1-8H2,(H,12,13,14)

InChI key

JKMHFZQWWAIEOD-UHFFFAOYSA-N

General description

Absorbance (1.0 M, H2O, 260 nm):≤0.05.

Absorbance (1.0 M, H2O, 280 nm): ≤0.04
A zwitterionic N-substituted aminosulfonic acid buffer. HEPES has its maximum buffering capacity very near the pH of mammalian tissue fluids (pKa of 7.31 at 37°C). Exhibits no metal binding and has a small temperature dependent ΔpKa of -0.014/°C.
A zwitterionic N-substituted aminosulfonic acid buffer. Useful in the pH 6.8-8.2 range. Has a pKa of 7.48 at 25°C.

Packaging

25 g in Plastic ampoule
5 kg in Fibre carton
100, 500 g in Glass bottle
1 kg in Glass bottle

Warning

Toxicity: Irritant (B)

Reconstitution

Following reconstitution, store at room temperature (20°C). Stock solutions are stable for up to 6 months at 20°C.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany
ULTROL is a registered trademark of Merck KGaA, Darmstadt, Germany

Storage Class Code

13 - Non Combustible Solids

WGK

WGK 1

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

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Certificate of Quality

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