Tris 496251 224177846 2008-07-07T17:58:23Z 198.176.189.201 /* Buffer details */ {{Chembox new | Name = Tris | ImageFile = Tris.png | ImageSize = 160px | ImageName = Chemical structure of tris | IUPACName = 2-Amino-2-hydroxymethyl-propane-1,3-diol | OtherNames = TRIS, Tris, Tris base, Tris buffer,<br />Trizma<sup>TM</sup>, Trisamine, THAM,<br />Tromethamine, Trometamol, Tromethane | Section1 = {{Chembox Identifiers | SMILES = C(C(CO)(CO)N)O | CASNo = 77-86-1 | RTECS = TY2900000 }} | Section2 = {{Chembox Properties | C = 4 | H = 11 | N = 1 | O = 3 | Appearance = White crystalline powder | Density = | Solubility = 220 g/100 ml (20°C) in water | MeltingPt = >175-176°C (448-449 K) | BoilingPt = 219°C (492 K) | pKa = 8.1 }} | Section7 = {{Chembox Hazards | ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/T7111.htm External MSDS] | MainHazards = Irritant | NFPA-H = 2 | NFPA-F = | NFPA-R = | FlashPt = Non-flammable | RPhrases = {{R36}}, {{R37}}, {{R38}}. | SPhrases = {{S26}}, {{S36}}. }} }} {{this|the chemical compound}} '''Tris''' is an abbreviation of the [[organic compound]] known as tris(hydroxymethyl)aminomethane, with the formula (HOCH<sub>2</sub>)<sub>3</sub>CNH<sub>2</sub>. Tris is extensively used in [[biochemistry]] and [[molecular biology]].<ref>Gomori, G., Preparation of Buffers for Use in Enzyme Studies. Methods Enzymology., 1, 138-146 (1955).</ref> In [[biochemistry]], tris is widely used as a component of [[buffer solution]]s, such as in [[TAE buffer|TAE]] and [[TBE buffer]], especially for solutions of [[nucleic acid]]s. It is a [[primary amine]] and thus undergoes the reactions associated with typical amines, e.g. condensations with aldehydes. ==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 pK<sub>a</sub> declines approximately 0.03 units per degree Celsius rise in temperature. * Silver-containing single-junction pH electrodes 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 (HOCH<sub>2</sub>)<sub>3</sub>CNO<sub>2</sub> . Reduction of the latter gives tris(hydroxymethyl)aminomethane.<ref>Sheldon B. Markofsky “Nitro Compounds, Aliphatic” Ullmann's Encyclopedia of Industrial Chemistry 2002 by Wiley-VCH, Wienheim, 2002. DOI: 10.1002/14356007.a17_401.</ref> ==Uses== The useful buffer range for Tris (7-9) coincides with the typical physiological pH of most living things. This, and its low cost, make Tris one of the most common buffer elements in use in the biology/biochemistry lab. ==References== <references/> [[Category:Alcohols]] [[Category:Amines]] [[Category:Buffers]] [[de:TRIS]] [[fr:Tris]] [[ja:トリスヒドロキシメチルアミノメタン]] [[pt:Tris]] [[zh:三羟甲基氨基甲烷]]