Synonyms: 2-Amino-2-(hydroxymethyl)-1,3-propanediol, THAM, Tris base, Trometamol, Tris(hydroxymethyl)aminomethane
Tris is extensively used in biochemistry and molecular biology as a component of buffer solutions, such as in TAE and TBE buffer, especially for solutions of nucleic acids. The useful buffer range for tris (7-9) coincides with the typical physiological pH of most living organisms. This, and its low cost, makes tris one of the most common buffers used in the biology/biochemistry lab. The pH of the buffer is adjusted with hydrochloric acid. The pH values of Tris buffers are temperature- and concentration-dependent. The pH increases about 0.03 unit per °C decrease in temperature, and decreases 0.03-0.05 unit per ten-fold dilution. Tris has a relatively high degree of fat solubility and may therefore permeate membranes. As a result this buffer is toxic for mammalian cell cultures. It is a primary amine and thus undergoes the reactions associated with typical amines, e.g. condensations with aldehydes. The pKa declines approximately 0.03 units per degree Celsius rise in temperature. Silver-containing single-junction pH electrodes (e.g., silver chloride electrode) are incompatible with Tris (Ag-tris precipitation clogs the junction). Double-junction electrodes are resistant to this problem and non-silver containing electrodes are immune. It is reported that Tris inhibits a number of enzymes and therefore, it should be used with care when studying proteins. Tris is also used as a primary standard to standardize acid solutions for chemical analysis.
pKa (25°C): 8.1
useful pH range: 6.0-9.0
Warning: For laboratory use only. Not fit for agricultural, household, clinical use or human consumption.
PH Value: 8.4