Description
Abbreviated as Tris HCl (TRIS hydrochloride), Tris (hydroxymethyl) aminomethane hydrochloride is an organic compound commonly utilized in buffer solutions such as TAE or TBE for electrophoresis gels. It boasts high solubility in water and offers utility within the pH range of 7.0-9.0.
Chemical Properties
TRIS hydrochloride is a white crystalline powder that has a pKa of 8.08 at 25°C and pH range of 7.0 to 9.0 that coincides with the physiological pH of most living organisms because of which it is commonly used as a component of buffer solutions in biology, biochemistry and molecular biology applications. Tris salts are also used for crystallization of proteins at various pH values. Neither Tris base nor Tris hydrochloride by itself provide adequate buffering capacity. Generally the two need to be mixed together to provide a buffer with pH between 7 and 9 to provide adequate buffering.
Uses
Tris Hydrochloride is a buffering medium for electrophoresis, molecular biology, and cell culture applications. It may be combined with Tris Base to simplify Tris buffer preparation. Tris Hydrochloride has been incorporated in coelomic fluid and in Cortland medium to store unfertilized rainbow trout eggs. In immunohistochemistry, Tris Hydrochloride has also been used with urea as a method for antigen retrieval.
Application
TRIS hydrochloride is highly soluble in water and is useful in the pH range 7.0-9.0. It is used in the preparation of Laemmli buffer, one of the most common SDS-PAGE buffers. In addition, Tris can also be used for many custom running and loading buffers, most often with glycine and SDS. The use of single-junction pH electrodes that contain silver should be avoided when determining the pH of a solution containing Tris buffer.
Preparation
The preparation of TRIS hydrochloride is as follows:After reacting 2-amino-1,3-propanediol (2.50 g, 27.44 mmol) and formic acid (1.26 g, 27.44 mmol) in 50 ml of water at room temperature for 3 hours, water was distilled off under reduced pressure, A liquid was obtained. By washing the obtained liquid,An ammonium formate salt (3.76 g, 27.44 mmol) was obtained as a colorless transparent liquid.
General Description
TRIS hydrochloride is mainly required for preparation of buffer at physiological range of 7.3 to 7.5. The prepared buffer is compatible with biological fluids. It is of importance to laboratories as a standard pH solution.
Purification Methods
Crystallise the salt from 50% EtOH, then from 70% EtOH. TRIS-hydrochloride is also available commercially in a highly pure state. Otherwise, recrystallise it from 50% EtOH, then 70% EtOH, and dry it below 40o to avoid risk of decomposition. [Beilstein 4 H 304.]
