Description_x000D_ General description_x000D_ HEPES has been described as one of the best all-purpose buffers available for biological research. At biological pH, the molecule is zwitterionic, and is effective as a buffer at pH 6.8 to 8.2 (pKa 7.55). It is typically used in cell culture at concentration between 5mM to 30 mM. HEPES has been used in a wide variety of applications, including tissue culture. It is commonly used to buffer cell culture media in air. HEPES finds its usage in in vitro experiments on Mg._x000D_ Application_x000D_ HEPES has been used as a component of:_x000D_ • Hank’s balanced salt solution, Dulbecco’s modified eagle’s medium and no-glucose DMEM, which are used for the preparation of tissue slices_x000D_ • Buffers used in localized conductance measurements on the basolateral side of culture inserts to examine cation selectivity_x000D_ Caution_x000D_ Concentrations of HEPES over 40mM may be toxic to some cell types._x000D_ Preparation Note_x000D_ Prepared from HEPES free acid and cell culture grade water.