69890 Sigma-Aldrich

MES hydrate

BioUltra, ≥99.5% (T)

Synonym: 2-(N-Morpholino)ethanesulfonic acid hydrate, 4-Morpholineethanesulfonic acid

  • CAS Number 1266615-59-1

  • Empirical Formula (Hill Notation) C6H13NO4S · xH2O

  • Molecular Weight 195.24 (anhydrous basis)

  •  MDL number MFCD00149409

  •  eCl@ss 32129211

  •  PubChem Substance ID 57652220



Related Categories Alphabetical, BioUltra Buffers, Biochemicals and Reagents, Biological Buffers, Zwitterionic More...
Quality Level   200
product line   BioUltra
assay   ≥99.5% (T)
form   powder or crystals
impurities   insoluble matter, passes filter test
ign. residue (900 °C)   ≤0.05%
pH   2.5-4.0 (25 °C, 0.5 M in H2O)
useful pH range   5.5 - 6.7
pKa    6.1
solubility   H2O: 0.5 M at 20 °C, clear, colorless
anion traces   chloride (Cl-): ≤50 mg/kg
  sulfate (SO42-): ≤100 mg/kg
cation traces   Al: ≤5 mg/kg
  As: ≤0.1 mg/kg
  Ba: ≤5 mg/kg
  Bi: ≤5 mg/kg
  Ca: ≤20 mg/kg
  Cd: ≤5 mg/kg
  Co: ≤5 mg/kg
  Cr: ≤5 mg/kg
  Cu: ≤5 mg/kg
  Fe: ≤5 mg/kg
  K: ≤50 mg/kg
  Li: ≤5 mg/kg
  Mg: ≤5 mg/kg
  Mn: ≤5 mg/kg
  Mo: ≤5 mg/kg
  Na: ≤50 mg/kg
  Ni: ≤5 mg/kg
  Pb: ≤5 mg/kg
  Sr: ≤5 mg/kg
  Zn: ≤5 mg/kg
λ   0.5 M in H2O
UV absorption   λ: 260 nm Amax: 0.025
  λ: 280 nm Amax: 0.020
SMILES string   O.OS(=O)(=O)CCN1CCOCC1
InChI   1S/C6H13NO4S.H2O/c8-12(9,10)6-3-7-1-4-11-5-2-7;/h1-6H2,(H,8,9,10);1H2


General description

MES is one of the "Good" buffers developed for biological applications. MES is not recommended at pH 7.4; other buffers should be considered. All qualities are tested for trace ions and all can be used for biological and biochemistry applications. This product is used in biochemical and biological techniques where highly purified products are needed.

Preparation Note

A buffer using MES free acid can be prepared by titrating the free acid with sodium hydroxide to the desired pH (pKa=±1). Alternatively, volumes of equimolar MES free acid and sodium MES can be mixed to attain the desired pH. Standard mixing tables using stock solutions to prepare a buffer of a given pH have been published.

Other Notes

Solubility/Stability: MES is soluble in water, giving a clear colourless solution at concentrations of 0.5M or higher. The pH of a solution should be between 2.5 and 5, depending on the concentration. Solutions are stable at 2-8°C for months.
Sterilization: Sterilization should be by filteration through 0.2μM filters. Autoclaving is not recommended by any sulfonic acid buffers. If buffers must be nuclease-free, it is best to treat the water, then add the buffer solids after autoclaving. When MES solutions are autoclaved, they turn yellow (although pH does not change measurably. The identity of the yellow breakdown product is unknown.

Easily compare specifications for MES hydrate products with the MES hydrate specification table.

Biological buffer; useful pH-range 5.8-6.5; Mobile phase component in brain tubulin isolation by amino-activated gel chromatography; Buffer in plant tissue culture.

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable

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