Description

• 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.[1] 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.[2]
• 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.