2- [bis (2-hydroxyethyl) amino] -2- (hydroxymethyl) -1,3-propanediol hydrochloride is a biological buffer, and its English name is BIS-TRIS HYDRACHLORIDE. It is a white powder with a purity of up to 98%. The molecular formula of this substance is C8H20ClNO5, with a molecular weight of 245.7. In biological experiments, 2- [bis (2-hydroxyethyl) amino] -2- (hydroxymethyl) -1,3-propanediol hydrochloride is mainly used to maintain the pH stability of the solution. Its pH range is approximately 5.8-7.2, making it a neutral buffering agent. It can maintain the pH stability of the solution by combining hydrogen ions, so it is widely used in some biological experiments that require precise pH control. In addition to being used as a biological buffer, 2- [bis (2-hydroxyethyl) amino] -2- (hydroxymethyl) -1,3-propanediol hydrochloride can also be used to prepare chromatography media and gel electrophoresis media. It has good salt and high temperature resistance, so it can also show good buffering performance under some high salt and high temperature experimental conditions. In summary, 2- [bis (2-hydroxyethyl) amino] -2- (hydroxymethyl) -1,3-propanediol hydrochloride is an important biological buffer with extensive application value.