TL;DR: A standard 50X TAE stock contains 2 M Tris, 1 M acetate and 50 mM EDTA. For 1 L: 242.3 g Tris base, 57.1 mL glacial acetic acid and 100 mL of 0.5 M EDTA pH 8.0, then water to 1 L. Dilute 1:50 to make 1X TAE.
TAE stands for Tris-acetate-EDTA. It is one of the two dominant running buffers for agarose gel electrophoresis of DNA and RNA, alongside TBE. TAE is frequently chosen for routine DNA gels and workflows where DNA will be excised and recovered from the gel.
50X TAE recipe
| Final volume | Tris base | Glacial acetic acid | 0.5 M EDTA pH 8.0 |
|---|---|---|---|
| 100 mL | 24.23 g | 5.71 mL | 10 mL |
| 500 mL | 121.14 g | 28.55 mL | 50 mL |
| 1 L | 242.28 g | 57.1 mL | 100 mL |
How to make 1 L of 50X TAE
- Add about 600–700 mL purified water to a large beaker.
- Dissolve 242.28 g Tris base completely.
- Add 57.1 mL glacial acetic acid carefully.
- Add 100 mL 0.5 M EDTA, pH 8.0.
- Mix thoroughly and bring to 1 L with purified water.
Safety: glacial acetic acid is corrosive. Handle in a fume hood with appropriate PPE.
How to make 1X TAE from 50X
| Final 1X volume | 50X TAE | Water |
|---|---|---|
| 100 mL | 2 mL | 98 mL |
| 500 mL | 10 mL | 490 mL |
| 1 L | 20 mL | 980 mL |
1X TAE final composition
- 40 mM Tris-acetate
- 1 mM EDTA
- pH approximately 8.3
TAE vs TBE: which should you use?
TAE and TBE do not behave identically. Primary electrophoresis studies show that borate interacts with DNA and agarose differently from acetate, changing mobility and electro-osmotic behaviour. TBE generally has higher buffering capacity, while TAE is often preferred for longer DNA fragments and downstream DNA recovery.
| Feature | TAE | TBE |
|---|---|---|
| Buffering capacity | Lower | Higher |
| Typical use | Routine agarose gels, DNA recovery | High-resolution small fragments, longer runs |
| Borate present | No | Yes |
Can I reuse TAE running buffer?
Reuse is possible for non-critical gels, but ionic composition and pH shift during electrophoresis. For quantitative or publication-quality comparisons, fresh buffer is safer.
Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| Gel runs hot | Buffer too concentrated or voltage too high | Confirm 1X dilution and reduce field strength. |
| DNA migrates poorly | Incorrect buffer or exhausted buffer | Prepare fresh 1X TAE and verify gel/buffer match. |
| Smearing | Overloaded DNA, degraded sample or excessive heat | Reduce load and voltage; check DNA quality. |
Frequently asked questions
Can I run a gel made with TAE in a TBE tank?
Do not mix buffer systems. Cast and run the gel in the same buffer to avoid discontinuities in ionic strength and migration.
Does EDTA need to be pH 8 before use?
Yes. EDTA dissolves and chelates effectively near pH 8; use a correctly prepared EDTA stock.
Related ABMIUM guides
Primary research references
- Stellwagen NC, Gelfi C, Righetti PG. The free solution mobility of DNA. Biopolymers. 1997.
- Stellwagen NC et al. DNA and buffers: interactions in neutral-pH buffers. Anal Biochem. 2000.
- Modification of gel architecture and TBE/TAE buffer composition to minimise heating during agarose gel electrophoresis. 2014.