MES is the common name for the compound 2-(N-morpholino)ethanesulfonic acid. Its chemical structure contains a morpholine

Morpholine

Morpholine is an organic chemical compound having the chemical formula O2NH. This heterocycle, pictured at right, features both amine and ether functional groups. Because of the amine, morpholine is a base; its conjugate acid is called morpholinium...

 ring. It has a molecular weight of 195.2 and the chemical formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 is C₆H₁₃NO₄S. Synonyms include: 2-morpholinoethanesulfonic acid; 2-(4-morpholino)ethanesulfonic acid; 2-(N-morpholino)ethanesulfonic acid; 2-(4-morpholino)ethanesulfonic acid; MES; MES hydrate; and morpholine-4-ethanesulfonic acid hydrate.