MES monohydrate
[CAS# 145224-94-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Sulfonic acid / sulfinic acid
• Name: MES monohydrate
• Synonyms: 2-(N-Morpholino)ethanesulfonic acid monohydrate
• Molecular Formula: C₆H₁₃NO₄S^.H₂O
• Molecular Weight: 213.25
• CAS Registry Number: 145224-94-8
• EC Number: 630-505-7
• SMILES: C1COCCN1CCS(=O)(=O)O.O

Properties

• Melting point: 300 ºC

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Specific target organ toxicity - single exposure	STOT SE	3	H336

Discovory and Applicatios

MES (2-(N-morpholino)ethanesulfonic acid) monohydrate is part of a series of biological buffers developed by Norman Good and coworkers in the mid-20th century. Collectively known as Good buffers, these buffers were designed to meet specific needs in biological and biochemical research. MES monohydrate was synthesized to provide effective buffer solutions in the near-neutral pH range, which is essential for maintaining stable conditions in a variety of experimental setups.

The molecular formula of MES monohydrate is C6H13NO4S·H2O. Its structure consists of a morpholine ring attached to an ethanesulfonic acid group, which gives it excellent buffering capacity. The monohydrate form means that it contains a water molecule, which enhances its solubility. MES has a pKa of 6.1 at 25°C, making it an ideal buffer for the pH range of 5.5 to 7.5 and is particularly useful in biological systems where neutral pH is often required.

MES monohydrate is widely used as a buffer in a variety of biochemical and molecular biology experiments. Its stable buffering capacity in the near-neutral pH range makes it suitable for enzymatic reactions, protein purification, and cell culture media. MES is particularly useful in electrophoresis, helping to maintain a consistent pH, ensuring accurate results for protein and nucleic acid separations.

In cell culture applications, MES monohydrate helps maintain the pH of the culture medium, providing a stable environment for cell growth and function. This stability is critical for sensitive cell lines and primary cultures, which require precise pH control for optimal growth and differentiation.

MES monohydrate is used in protein purification protocols such as ion exchange chromatography and affinity chromatography. Its buffering capacity helps maintain the pH of the solution, ensuring that the protein remains in its native functional state during the purification process. This is essential for maintaining protein stability and activity.

In electrophoresis, MES monohydrate is used to prepare buffer solutions that maintain a stable pH during nucleic acid and protein separations. For example, in SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis), MES buffer helps ensure consistent migration of proteins, allowing accurate determination of their molecular weights.

MES monohydrate is an important component in the formulation of diagnostic reagents, especially those that require a stable pH. Its nontoxic nature and compatibility with a variety of biological systems make it suitable for use in diagnostic assays and kits.