Merck, M3058-500G, MES sodium salt

General description
MES is one of the so-called "Good" buffers developed for biological applications. 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 solutions of MES free acid and MES sodium 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.
4-Morpholineethanesulfonic acid, sodium salt (MES) is a popular zwitterionic buffer in scientific research due to its excellent properties. It can buffer solutions effectively within a pH range of 5.5-6.5 with a pKa value of 6.1. This product is BioPerformance certified and it finds extensive application as a buffering agent in biochemistry and molecular biology experiments, contributing to the stabilization of pH in different biological reactions including western blotting, cell culture and electrophoresis.
Application
MES sodium salt has been used as a coupling buffer during the coupling of MAbs onto amine-reactive sensors. It has also been used as a component of germination medium and shoot induction medium during in vitro plant regeneration.
MES sodium salt has been employed as a coupling buffer for amine-reactive sensors at either pH 4.5 or pH 5.0 to facilitate the coupling of monoclonal antibodies (MAbs) onto the sensors, used in hybridization studies with fluorescently-labeled complementary strands and microarray slide washing during microarray analysis, and played a role in preparing a new set of RNA phosphoramidites compatible with in situ photolithography for growing RNA oligonucleotides on microarrays.
Features and Benefits

• Suitable for Molecular Biology and Cell Culture
• Tested for Endotoxins and Total Aerobic Microbial Count
• Free from DNase, NICKase, RNase, and Protease
• Effective Buffering from pH 5.5-6.7 (25 °C) with a pKa of 6.1 (25 °C)

Preparation Note
MES Sodium is soluble in water, giving a clear colourless solution at 25g in 50mL water (approximately 2.3M). The pH of a solution should be between 9 and 10 depending on concentration. Solutions are stable at 2-8°C for months. Sterilization should be done by filteration through 0.2μm filters. Autoclaving is not recommended. If buffers must be nuclease-free, it is best to treat the water first, 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.
Other Notes
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