- Tris is also known as THAM, Tris, Tris base, Trizma, Tris(hydroxymethyl)aminomethane
- Tris has a pKa of 8.07 at 25°C.
- It has an effective pH range between 7.0 and 9.0. This buffer range correspond to physiological pH range.
- Silver-containing single-junction pH electrodes (e.g., silver chloride electrode) are incompatible with Tris (Ag-tris precipitation clogs the junction).
- Tris has been shown to inhibit activity of many enzymes.
- Tris base (C4H11NO3, Molecular Weight: 121.14)
- Conc HCl
- pH paper (optional)
- Deionized / Milli-Q water
- Equipment and disposable
- Measuring cylinder
- Conical flask / Beaker
- Magnetic stirrer
- pH meter
Composition: 1 M Tris.Cl
Preparation of 1000 ml of 1 M Tris.Cl, pH 7.2
Prior to start: Calibrate the pH meter with pH standard buffers
Step 1: To prepare, 1000 ml of 1 M Tris.Cl solution, weigh out 121.14 gram Tris base (molecular weight = 121.14) and transfer to a 2 liter beaker/conical flask. Dissolve tris base in 800 ml deionized/Milli-Q water using magnetic stirrer.
- One can use manual shaking using a glass pipette. Magnetic stirrer makes the dissolving process easy and convenient.
- Do not dissolve in 1000 ml of deionized/Milli-Q water. In most cases, especially when the solute amount is large, the volume of the solution increases when solute is dissolved in solvent. It is essential to dissolve the solute in a small volume of solvent (e.g., 80% of the required volume). After the solute is completely dissolved and pH is adjusted (if required), make up the correct volume with the solvent.
Step 2: Adjust the pH 7.2 with concentrated HCl.
Notes: The pH of 1 M Tris solution at 25°C will be between 10.0 – 11.5
- Approximately 45 ml HCl is required to adjust the pH.
- One can set the desired pH of the solution at this point with the addition of HCl (approximately 40-45 ml conc HCl is required for setting 1M Tris solution pH 7 – 9)
- Use appropriate measures to protect yourself while handling the concentrated HCl.
Step 3: Adjust the volume to 1000 ml with deionized/Milli-Q water.
Step 4: Autoclave the solution for 20 minutes at 15 lb/sq.in. on liquid cycle.
Solution can be stored at room temperature for several weeks.
The solution is used as a buffer for several biological applications. Some of the most common applications are
- Preparation of TAE
- Preparation of TBE
- Preparation of TE
|To prepare Tris-Cl, pH 7.2 of various volume (100 ml, 250 ml, 500 ml and 1,000 ml) and molarity (100 mM, 250 mM, 500 mM and 1M), follow the table.|
|Conc. / Volume||100 ml||250 ml||500 ml||1,000 ml|
|10 mM||0.12 g||0.3 g||0.6 g||1.21 g|
|100 mM||1.21 g||3.03 g||6.06 g||12.1 g|
|500 mM||6.05 g||15.13 g||30.25 g||60.5 g|
|1 M||12.1 g||30.25 g||60.5 g||