Tris: Difference between revisions
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Tris is a common buffering agent and is short for tris[hydroxymethyl]aminomethane (C<sub>4</sub>H<sub>11</sub>NO<sub>3</sub>). | [[Image:160px-Tris.png|thumb|Chemical structure of Tris - 2-Amino-2-hydroxymethyl-propane-1,3-diol]] | ||
[http://en.wikipedia.org/wiki/Tris Tris] is a common buffering agent and is short for tris[hydroxymethyl]aminomethane (C<sub>4</sub>H<sub>11</sub>NO<sub>3</sub>, 2-Amino-2-hydroxymethyl-propane-1,3-diol). | |||
* The formula weight is 121.14 | * The formula weight is 121.14 | ||
* The pKa of Tris is 8.3 | * The pKa of Tris is 8.3 | ||
* dpK<sub>a</sub>/dT is -.028 | * dpK<sub>a</sub>/dT is -.028 | ||
* A buffer at pH 6.8 at | * A buffer at pH 6.8 at 25°C will have a pH of 6.46 at 37°C | ||
** Note that adding HCl during titration will affect the temperature of the solution | ** Note that adding HCl during titration will affect the temperature of the solution | ||
* Dilution by a factor of 10 will reduce the pH by 0.1 pH units. | * Dilution by a factor of 10 will reduce the pH by 0.1 pH units. | ||
== Preparing a 1M Tris, pH 7.4 solution, from [http://biologicalworld.com/trisbuffer.htm biologicalworld] == | |||
* Weigh 121.1 g Tris in 700 ml double distilled water | |||
* Do not start with too much water; otherwise, the volume after pHing may be too great | |||
* Start stirring, and then check the pH | |||
* With a 3M HCl solution, start to pH the solution such that the pH reaches 7.4 | |||
(Be careful not to inhale the HCl.) | |||
* Add with double distilled water up to 1L | |||
* Filter or autoclave if necessary | |||
* May be better to store at 4 degrees C | |||
* Dilute to appropriate concentration for use in biochemistry or molecular biology experiments. 20 mM or 50 mM Tris, pH 7.4 solutions are common. | |||
== Stability == | |||
* 18 months for Tris-HCl buffer according to this data sheet [http://www.labvision.com/pdf/uvdatasheet/AP-9005-XXX.pdf] | |||
* 2 years for Tris-EDTA according to this data sheet [http://www.labtech.co.uk/downloads/biothema/21-500.pdf] | |||
== See also == | |||
* [[TBS]] - tris-buffered saline | |||
* [[TBST]] - tris-buffered saline with Tween | |||
[[Category:Material]] | |||
[[Category:Buffers]] | |||
Latest revision as of 10:17, 14 October 2008
Tris is a common buffering agent and is short for tris[hydroxymethyl]aminomethane (C4H11NO3, 2-Amino-2-hydroxymethyl-propane-1,3-diol).
- The formula weight is 121.14
- The pKa of Tris is 8.3
- dpKa/dT is -.028
- A buffer at pH 6.8 at 25°C will have a pH of 6.46 at 37°C
- Note that adding HCl during titration will affect the temperature of the solution
- Dilution by a factor of 10 will reduce the pH by 0.1 pH units.
Preparing a 1M Tris, pH 7.4 solution, from biologicalworld
- Weigh 121.1 g Tris in 700 ml double distilled water
- Do not start with too much water; otherwise, the volume after pHing may be too great
- Start stirring, and then check the pH
- With a 3M HCl solution, start to pH the solution such that the pH reaches 7.4
(Be careful not to inhale the HCl.)
- Add with double distilled water up to 1L
- Filter or autoclave if necessary
- May be better to store at 4 degrees C
- Dilute to appropriate concentration for use in biochemistry or molecular biology experiments. 20 mM or 50 mM Tris, pH 7.4 solutions are common.
Stability
- 18 months for Tris-HCl buffer according to this data sheet [1]
- 2 years for Tris-EDTA according to this data sheet [2]
