HEPES buffer, effective at a pH range of 6.8 to 8.2, is a staple buffer often used in cell culture to maintain physiological pH. Compared to bicarbonate-based buffers, HEPES is more resistant to changes in pH due to respiration-induced changes in carbon dioxide concentration. It also exhibits membrane impermeability, chemical and enzymatic stability, and low visibility and optical density. It is highly soluble and is easy to prepare. HEPES buffers should be used in concentrations ranging from 10 mM to 25 mM as lower concentrations are usually insufficient to buffer drastic PH fluctuations while higher concentrations can cause cytotoxicity. Visit the supplier page for more reagent information, including details on formulation and format.