low moisture content, ≥99% (titration)

4-Morpholineethanesulfonic acid, 2-(N-Morpholino)ethanesulfonic acid
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
Beilstein/REAXYS Number:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


≥99% (titration)




≤1.0% water


2.5-4 (25 °C, 97.6 g/L)

useful pH range

5.5 - 6.7



Featured Industry

Diagnostic Assay Manufacturing

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General description

MES is one of the Good′s buffers, the most extensively used biological buffers. MES is a zwitterionic N-substituted aminosulfonic acid with a morpholinic ring. It does not form complexes with majority of the metals used in environmental and biological studies. It is easily soluble in water and has minimum lipid solubility, making it impermeable to membranes.


MES has been used as a component of the elution buffer used to elute plasma from α2-macroglobulin affinity column. It has been used as an activation buffer during antibody conjugation to microparticles. MES has been used in the functionalization of microchannels during the creation of microfluidic-integrated surface plasmon resonance (SPR) platform for pathogen detection.


50, 250 g in poly bottle
1 kg in poly bottle


Low moisture

Other Notes

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

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


  1. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  2. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  3. What does low moisture content mean in the description of Product M3671, MES - low moisture?

    The amount of water/moisture for MES (M3671) is tested by Karl Fisher and meets a specification of less than 1%. The other MES Hydrates offered have a specification of less than 9%.

  4. What is the solubility of Product M3671, MES - low moisture?

    We test the solubility of Prod. No. M3671 at 20 grams in 80 mL of water. A clear, colorless solution is obtained. This concentration is not necessarily the upper solubility limit of MES in water.

  5. What is the pH of a solution of Product M3671, MES - low moisture?

    The pH of a 0.5 M solution in water should be between 2.5 and 4.0.

  6. Is Product M3671, MES - low moisture, autoclavable?

    Autoclaving is not recommended for any sulfonic acid buffer solution. Sterilization of a MES buffer solution can be accomplished by filtering it through a 0.2 micron filter.

  7. How does one prepare a buffer using Product M3671, MES - low moisture, free acid?

    A buffer using MES free acid can be prepared by titrating the free acid with sodium hydroxide to the desired pH. Alternatively, volumes of equimolar MES free acid and sodium MES can be mixed to attain the desired pH.

  8. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  9. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  10. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

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