| 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. |
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| Solubility/Stability | MES is soluble in water, giving a clear colourless solution at concentrations of 0.5 M or higher. The pH of a solution should be between 2.5 and 5, depending on the concentration. Solutions are stable at 2-8C for months. |
| Sterilization | Sterilization should be by filteration through 0.2 uM filters. Autoclaving is not recommended by any sulfonic acid buffers. If buffers must be nuclease-free, it is best to treat the water, and 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. |
| Application | In the preparation of a solution used for the suspension and dilution of protoplasts to measure the density and number of protoplasts using a haemocytometer |
| As a component of Murashige and Skoog basal salt media | |
| In the preparation of total ionic strength adjustment buffer |
MES monohydrate is a buffering agent used in biochemistry and molecular biology that was selected and described by Goodet al.It is a zwitterionic, morpholinic buffer that is useful for a pH range of 5.5 – 6.7 and commonly used for cell culture media, as a running buffer in electrophoresis, and for protein purification in chromatography. MES lacks the ability to form a complex with most metal ions and is recommended for use as a non-coordinating buffer in solutions with metal ions. MES is often used in buffered culture media for bacteria, yeast, and mammalian cells. It is toxic towards plants at high concentrations, but can be used in culture media at lower concentrations for plants. Due to low ionic mobility, MES is regarded as an excellent buffer for use in capillary electrochromatography. MES is often employed as a substitute for the highly toxic cacodylate, as well as a substitute for the non-zwitterionic buffers citrate and malate. MES complexes with some organotin(IV) molecules that are being explored as antitumor agents.
