How to Make a TAE Buffer in 3 Steps

This buffer is used to study DNA movement

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TAE buffer is a solution made up of Tris base, acetic acid and EDTA (Tris-acetate-EDTA). It is historically the most common buffer used for agarose gel electrophoresis in the analyses of DNA products resulting from PCR amplification, DNA purification protocols or DNA cloning experiments.

This buffer has a low ionic strength and low buffering capacity. It is best suited to electrophoresis of large (>20 kb) pieces of DNA and will need to be replaced frequently or recirculated for longer (>4 h) gel run times.

With that in mind, you may want to consider several batches of the buffer.

Given that the buffer is easy to make and the steps can be carried out quickly, making more than one batch at a time shouldn't be particularly time-consuming or difficult to pull off. Using the instructions below, it should take just 30 minutes to make the TAE buffer. Here's how:

Prepare a Stock Solution of EDTA

An EDTA (ethylenediamine tetraacetic acid) solution is prepared ahead of time. EDTA will not go completely into solution until the pH is adjusted to about 8.0. For a 500 milliliter stock solution of 0.5 M EDTA, weigh out 93.05 grams of EDTA disodium salt (FW = 372.2). Dissolve in 400 milliliter deionized water and adjust the pH with sodium hydroxide (NaOH). Top up the solution to a final volume of 500 milliliters.

Whip Up a Stock Solution of TAE

Make a concentrated (50x) stock solution of TAE by weighing out 242 grams of Tris base (FW = 121.14) and dissolving it in approximately 750 milliliters of deionized water.

Carefully add 57.1 milliliters of glacial acid and 100 milliliters of 0.5 M EDTA (pH 8.0). After that, adjust the solution to a final volume of 1 liter. This stock solution can be stored at room temperature. The pH of this buffer is not adjusted and should be about 8.5.

Prepare a Working Solution of TAE

The working solution of 1x TAE buffer is made by simply diluting the stock solution by 50x in deionized water.

Final solute concentrations are 40 mM. Tris acetate and 1 mM EDTA. The buffer is now ready for use in running an agarose gel.

What You Need for the Buffer

Since making the TAE buffer only requires a quick and simple set of instructions, the amount of materials needed for it aren't excessive. You'll just need EDTA disodium salt, Tris base and glacial acetic acid.

Making the buffer also requires a pH meter and calibration standards, as appropriate. You'll also need 600 milliliter and 1500 milliliters beakers or flasks as well as graduated cylinders. Finally, you'll need deionized water, stir bars and stir plates.

Wrapping Up

Where do you plan to make the buffer--at a school site, a work site, or another location, such as your home? Check the inventory before you begin to make sure you have all of the above materials for the TAE buffer.

If you'd rather not have to pay for materials, opting to make the buffer outside of your home is recommended. You can easily order the materials you need online or visit a specialty store for them.

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