TL;DR: A standard 10X TBE stock contains 0.89 M Tris, 0.89 M borate and 20 mM EDTA. For 1 L: 108 g Tris base, 55 g boric acid and 40 mL of 0.5 M EDTA pH 8.0, then water to 1 L. Dilute 1:10 to make 1X TBE.
TBE stands for Tris-borate-EDTA. It is a high-buffering-capacity running buffer used for agarose and polyacrylamide electrophoresis of nucleic acids. Compared with TAE, TBE is often chosen for longer runs and high-resolution separation of smaller fragments.
10X TBE recipe
| Final volume | Tris base | Boric acid | 0.5 M EDTA pH 8.0 |
|---|---|---|---|
| 100 mL | 10.8 g | 5.5 g | 4 mL |
| 500 mL | 54 g | 27.5 g | 20 mL |
| 1 L | 108 g | 55 g | 40 mL |
How to make 1 L of 10X TBE
- Add about 700–800 mL purified water to a clean beaker.
- Dissolve 108 g Tris base.
- Add 55 g boric acid and mix until dissolved.
- Add 40 mL 0.5 M EDTA, pH 8.0.
- Bring to 1 L with purified water and mix thoroughly.
Do not routinely adjust the pH if the correct components and concentrations are used. The final pH is typically around 8.3.
How to make 1X TBE
| Final 1X volume | 10X TBE | Water |
|---|---|---|
| 100 mL | 10 mL | 90 mL |
| 500 mL | 50 mL | 450 mL |
| 1 L | 100 mL | 900 mL |
1X TBE final composition
- 89 mM Tris
- 89 mM borate
- 2 mM EDTA
TBE vs TAE
Primary electrophoresis studies show that borate can interact with DNA and agarose, which changes mobility and electro-osmotic behaviour relative to TAE. TBE generally buffers more strongly during long runs, whereas TAE is commonly preferred when DNA recovery from the gel is the next step.
Why can concentrated TBE precipitate?
Highly concentrated TBE can form precipitate during storage, especially at low temperature. A 5X stock is often more storage-stable than 10X. If a stock develops persistent crystals or cloudiness that does not clear with gentle warming and mixing, remake it.
Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| Buffer precipitates | Concentrated stock or cold storage | Use 5X stock or remake if crystals persist. |
| Gel overheats | Buffer too concentrated or voltage too high | Confirm 1X dilution and reduce field strength. |
| Unexpected mobility | TAE/TBE mismatch | Cast and run the gel in the same buffer system. |
Frequently asked questions
Is 0.5X TBE ever used?
Yes. Some high-voltage or lower-conductivity electrophoresis workflows use 0.5X TBE, but keep gel and tank buffer matched.
Can TBE interfere with downstream reactions?
Borate carryover can be undesirable in selected enzymatic workflows, so purified DNA or TAE may be preferable where sensitive downstream reactions follow.
Related ABMIUM guides
Primary research references
- Stellwagen NC, Gelfi C, Righetti PG. The free solution mobility of DNA in TBE and TAE. Biopolymers. 1997.
- Stellwagen NC, Stellwagen E. DNA and buffers: the hidden danger of complex formation. Biopolymers. 2000.
- Modification of gel architecture and TBE/TAE buffer composition to minimise heating. 2014.