HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) buffer is a zwitterionic organic chemical buffering agent. It is commonly used in biological and biochemical research because of its ability to maintain a stable pH in a narrow range, typically around 7.2 to 7.5. This stability is crucial for many histological techniques where pH changes could affect the integrity of tissues and the accuracy of experimental results.
