HEPES dry substance, 100 g

HEPES (N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid) is a zwitterionic organic buffer agent commonly used in cell culture media to maintain the pH of the medium. HEPES buffers within a pH range of 6.7 to 8.6. It is not membrane-permeable, has limited reactivity, and is chemically and enzymatically stable. Adding 10 to 25 mM HEPES to your cell culture medium therefore offers an alternative to sodium bicarbonate when cell cultures must be grown without CO₂ or provides additional buffering capacity when stored outside a CO₂ incubator for extended periods.