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MES hydrate

BioUltra, ≥99.5% (T)

4-Morpholineethanesulfonic acid, 2-(N-Morpholino)ethanesulfonic acid hydrate
Empirical Formula (Hill Notation):
C6H13NO4S · xH2O
CAS Number:
Molecular Weight:
195.24 (anhydrous basis)
MDL number:
PubChem Substance ID:

product line


Quality Level


≥99.5% (T)


powder or crystals


insoluble matter, passes filter test

ign. residue (900 °C)



2.5-4.0 (25 °C, 0.5 M in H2O)

useful pH range

5.5 - 6.7




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


0.5 M in H2O

UV absorption

λ: 260 nm Amax: 0.025
λ: 280 nm Amax: 0.020

SMILES string




InChI key


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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

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

Storage Class Code

13 - Non Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves

Certificate of Analysis

Certificate of Origin

E Lacey et al.
Journal of chromatography, 525(1), 71-84 (1990-01-26)
In the present study, we report the isolation of the acidic structural protein tubulin using a number of amino-activated gels. Crude 100,000 g supernatant derived from sheep brain was applied to gels activated with either aminohexyl, aminoethyl, argininyl, diethylaminoethyl, lysinyl...
M De Block
Plant physiology, 93(3), 1110-1116 (1990-07-01)
Tissue culture conditions and transformation have been established for both aspen and poplar. The use of previously described culture conditions resulted in shoot tip necrosis in the shoot cultures and necrosis of stem and leaf explants. Shoot tip necrosis could...
D.E. Parfitt
Sci. Hortic., 36, 157-157 (1988)
Dawson, R.M.C. et al.
Data for Biochemical Research, 410- 410 (1987)
Good NE et al.
Biochemistry, 5, 467-477 (1966)

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