2- [(Tri (hydroxymethyl) methyl) amino] -1-ethanesulfonic acid sodium, also known as TES Na, is a commonly used zwitterionic buffer in the field of biochemistry. The following are its usage methods and precautions: Usage: TES Na usually exists in the form of white powder and can be dissolved in water to form a colorless and transparent solution. When it is necessary to maintain the pH stability of the solution, TES Na can be added. For example, in biological experiments, if it is necessary to conduct experiments within a specific pH range, TES Na can be added to help maintain pH stability. Precautions for use: TES Na has good buffering ability at room temperature, with a pH range of approximately 6.8-8.2 and a pKa value of 7.5. Within this pH range, TES Na can effectively maintain the pH stability of the solution. Although TES Na has a wide range of applications in biological research, it may not be suitable for certain specific experiments. For example, the Folin protein assay experiment cannot use TES Na. Therefore, it is important to pay attention to this when using TES Na.