TAE buffer
TAE buffer is a buffer solution containing a mixture of Tris base, acetic acid and EDTA.
In molecular biology it is used in agarose electrophoresis typically for the separation of nucleic acids such as DNA and RNA. It is made up of Tris-acetate buffer, usually at pH 8.3, and EDTA, which sequesters divalent cations. TAE has a lower buffer capacity than TBE and can easily become exhausted, but linear, double stranded DNA runs faster in TAE.
Previously, Brody & Kern simplified electrophoretic buffers by substituting TBE and TAE buffers for a more efficient and inexpensive conductive media in gel systems.
Uses
TAE buffer is used as both a running buffer and in agarose gel. Its use in denaturing gradient gel electrophoresis methods for broad-range mutation analysis has also been described. TAE has been used at various concentrations to study the mobility of DNA in solution with and without sodium chloride. However, high concentrations of sodium chloride in a DNA sample retard its mobility. This may lead to incorrect interpretations of the resulting DNA banding pattern.Preparation
TAE buffer is commonly prepared as a 50× stock solution for laboratory use. A 50× stock solution can be prepared by dissolving 242 g Tris base in water, adding 57.1 ml glacial acetic acid, and 100 ml of 500 mM EDTA solution, and bringing the final volume up to 1 litre. This stock solution can be diluted 49:1 with water to make a 1× working solution. This 1× solution will contain 40 mM Tris, 20 mM acetic acid, and 1 mM EDTA.| No. | Name | Per 1 mole | Main solution | 50× | 1× solution | 1X |
| 1 | Tris base | 121.1 g/l | 2 M | 242.2 g/l | 40 mM | 4.844 g/l |
| 2 | acetic acid | 57.1 ml/l | 1 M | 57.1 ml/l | 20 mM | 1.21 ml/l |
| 3 | EDTA disodium salt dihydrate | 372.24 g/l | 50 mM | 18.612 g/l | 1 mM | 0.372 g/l |
2 M = 2000 mM so 2000 mM /50 = 40 mM for 1×.
1M = 1000 mM so 1000 mM /50 = 20 mM for 1×.
50 mM /50 = 1 mM for 1×.
First of all, these ingredients should be dissolved in 500 ml, then made up to 1000 ml.
Note: EDTA will take more time to dissolve, so while dissolving EDTA use magnetic stirrer.
A step-by-step recipe of the preparation method for 50× TAE buffer is available on protocols.io.