Description
useful pH range 6.8 - 8.2 pKa (25 °C) 7.5HEPES is used in many media because it has more buffering capacity in the physiologic pH range of 7.2 - 7.4 at 37°C than sodium bicarbonate. It is commonly added at concentrations between 10 mM and 25 mM. Higher levels cause cytotoxicity. Because bicarbonate is nutritionally necessary for most cells, HEPES should be added in addition to, not in place of, sodium bicarbonate