TAE and TBE buffer recipes for agarose gels
Concentrated TAE and TBE stock recipes, what each is actually good for, and why TBE gels run sharper but ruin downstream enzymatic steps.
50× TAE and 10× TBE 1 L of concentrated stock
Preparation time about 25 minutes.
| Component | Formula weight | Amount |
|---|---|---|
| — 50× TAE — | ||
| Tris base | 121.14 g/mol | 242 g |
| Glacial acetic acid | 60.05 g/mol | 57.1 mL |
| 0.5 M EDTA pH 8.0 | — | 100 mL |
| — 10× TBE — | ||
| Tris base | 121.14 g/mol | 108 g |
| Boric acid | 61.83 g/mol | 55 g |
| 0.5 M EDTA pH 8.0 | — | 40 mL |
Procedure
- Dissolve the Tris base in about 700 mL of deionised water.
- Add the acid component — glacial acetic acid for TAE, boric acid for TBE. Add acetic acid in a fume hood.
- Add the 0.5 M EDTA stock.
- Make up to 1 L. Do not adjust the pH; the recipe is self-setting.
- Store at room temperature. Dilute fresh for each gel run.
What matters here
TAE for downstream work, TBE for resolution
TAE has low buffering capacity and exhausts during long runs, but DNA extracted from a TAE gel ligates and amplifies well. TBE buffers far better and gives sharper bands on small fragments, but borate inhibits ligase and many polymerases and is a nuisance to remove.
Large fragments run better in TAE
Above about 10 kb, TAE gives noticeably better separation. Below 1 kb, TBE wins.
Reusing running buffer
You can reuse buffer for two or three short runs, but the ion depletion at the electrodes shows up as smiling bands and eventually as failure to migrate.
Frequently asked questions
Bands smile or bow
Buffer is exhausted or the gel overheated. Use fresh buffer and drop the voltage.
Boric acid will not dissolve
It is slow in cold water. Warm gently and be patient — it does go in.
Ligation fails after gel extraction
Classic borate carryover from TBE. Switch to TAE for anything you plan to ligate, or add extra wash steps to the column protocol.