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| Tris | |
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| IUPAC name | 2-Amino-2-hydroxymethyl-propane-1,3-diol |
| Other names | TRIS, Tris, Tris base, Tris buffer, TrizmaTM, Trisamine, THAM, Tromethamine, Trometamol, Tromethane |
| Identifiers | |
| CAS number | 77-86-1 |
| RTECS number | TY2900000 |
| SMILES |
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| Properties | |
| Molecular formula | C4H11NO3 |
| Molar mass | 121.14 g mol−1 |
| Appearance | White crystalline powder |
| Melting point |
>175-176°C (448-449 K) |
| Boiling point |
219°C (492 K) |
| Solubility in water | ~50 g/100 ml (25°C) in water |
| Acidity (pKa) | 8.1 |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritant |
| NFPA 704 |
 0
2
0
|
| R-phrases | R36, R37, R38. |
| S-phrases | S26, S36. |
| Flash point | Non-flammable |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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'Tris (also known as THAM) is an abbreviation of the organic compound known as tris(hydroxymethyl)aminomethane, with the formula (HOCH2)3CNH2. Tris is extensively used in biochemistry and molecular biology.1 In biochemistry, tris is widely used as a component of buffer solutions, such as in TAE and TBE buffer, especially for solutions of nucleic acids. It is a primary amine and thus undergoes the reactions associated with typical amines, e.g. condensations with aldehydes.
Contents |
Buffering features
Tris has a pKa of 8.06, which implies that the buffer has an effective pH range between 7.0 and 9.2.
Buffer details
- 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 toxic to mammalian cells.
- A common variant of tris (aka tris base) is tris-HCl, the acid salt. When titrated to a specific pH with the corresponding counter ion (OH- for tris-HCl, H+ for tris base) they are equivalent. However, the molecular weights are different and must be correctly accounted for in order to arrive at the expected buffer strength.
Preparation
Tris is prepared in two steps from nitromethane via the intermediate (HOCH2)3CNO2 . Reduction of the latter gives tris(hydroxymethyl)aminomethane.2
Uses
The useful buffer range for Tris (7-9) coincides with the typical physiological pH of most living organisms. This, and its low cost, make Tris one of the most common buffers used in the biology/biochemistry lab.
Medical
Tris (usually known as THAM in this context) is used as alternative to sodium bicarbonate in the treatment of metabolic acidosis.3
References
- ^ Gomori, G., Preparation of Buffers for Use in Enzyme Studies. Methods Enzymology., 1, 138-146 (1955).
- ^ Sheldon B. Markofsky “Nitro Compounds, Aliphatic” Ullmann's Encyclopedia of Industrial Chemistry 2002 by Wiley-VCH, Wienheim, 2002. DOI: 10.1002/14356007.a17_401.
- ^ Kallet, RH; Jasmer RM, Luce JM et al. (April 2000). "The treatment of acidosis in acute lung injury with tris-hydroxymethyl aminomethane (THAM)". American Journal of Respiratory and Critical Care Medicine 161 (4): 1149–1153. PMID 10764304, http://ajrccm.atsjournals.org/cgi/content/full/161/4/1149.
Wikipedia content modification information:
- This page was last modified on 21 November 2008, at 20:06.
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