About EDTA solution
Ethylenediaminetetraacetic acid (EDTA) solution, at 0.5 M pH 8.0, is a commonly used solution utilised as a ligand and chelating agent. EDTA is particularly useful at sequestering metal ions, such as Ca2+ and Mg2+. Since nucleases require metal ions, EDTA solutions are used to protect DNA and RNA from degradation.
The recipe below is used to prepare a 100 mL 0.5M EDTA pH 8.0 solution.
|Reagent||Mass / Volume||Final concentration|
|EDTA disodium salt, dihydrate||18.61 g||0.5 M|
|Distilled H2O||80 mL|
How to make 0.5M EDTA pH 8.0
- Weigh out 18.61 g EDTA disodium salt, dihydrate and add to a 100 mL Duran bottle.
- Measure out 80 mL distilled water and add to the Duran bottle.
- Add a magnetic flea and place on a magnetic stirring plate to mix the solution. The EDTA salt will not go into solution until the pH reaches 8.0.
- Add a pH meter into the solution to observe the pH.
- To dissolve the salt, add sodium hydroxide (NaOH) pellets to the solution. Add a few pellets at a time and wait until the pellets have fully dissolved before adding more. It may take around 2 g of NaOH pellets before the pH is at 8.0.
- Once fully dissolved (this will take some time so be patient), top up the solution to 100 mL using distilled water, if necessary.
- To sterilise, autoclave the solution on a liquid cycle (20 min at 15 psi).
Storage of 0.5M EDTA pH 8.0 solution
Store 0.5M EDTA pH 8.0 solution at room temperature (+15oC – +25oC).
The final 0.5M EDTA pH 8.0 solution is not classified as hazardous. However, always be sure to read the safety data sheet before use.