2-[(2-Hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]ethanesulfonic acid;
N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulfonic acid;
2-[Tris-(Hydroxymethyl)methyl amino}-1-ethane sulfonic acid

Technical Data

CAS Number: 7365-44-8
Molecular Formula: C6H15NO6S
Molecular Weight: 229.25
Beilstein Registry Number: 1957061
EC Number: 230-906-3

FabriChem Specifications

Assay (Titration, dried basis)99.0% Min.
AppearanceWhite Powder
Solubility (5% in H2O)Clear and Complete
Moisture ( LOD )1.0% Max.
Pka 7.2 – 7.6
pH ( 1% in H2O )4.2 – 4.8
UV (0.1M in H2O):
A260 nm0.02 Max
A280 nm0.02 Max.

Molecular Structure



TES [2-[Tris-(Hydroxymethyl)methyl amino}-1-ethane sulfonic acid] is one of the known buffering agents used for biochemical and biological research. These buffering agents are now collectively referred to as “Good’s Buffers”. Good’s Buffers are important tools used in modern biological laboratories for a variety of their properties, including but not limited to being zwitterionic (aka hybrid or dipolar) compounds.