As, MES - Storage of the solutions: As, MES (Aug/08/2007 )

Hi! How long I can store 0.1M Acetosyrengone and 1M MES (2-(n-morpholino)-ethanesulfonic acid) at 4C or may be I have to store them at -20C? Thank you.

MES is not that stable at 4°
It's recommended, as MOPS, to be stored in aluminium wrapped bottle for 1 month.