Corning 100 mL Hepes, Liquid 1m Solution (238.3 Mg/ mL)

HEPES (N-2-hydroxyethylpiperazine-N-2-ethanesulphonic acid) provides an alternative to the use of bicarbonate for buffering because it does not require elevated levels of CO2. Unlike the low pKa of bicarbonate, HEPES has a pKa of 7.66 making it a much stronger buffer in the pH 7.2-7.6 range than bicarbonate buffer. Potential disadvantages of HEPES include toxicity over 100 mm and lack of nutritive value to the cell. The recommended working concentration is 10-25 mM.