EDTA

EDTA: Ethylenediaminetetraacetic acid

This comes as disodium salt dihydrate.




First time I tried to make it during by degree education, I just weighed the appropriate amount and tried dissolving it in water by shaking the flask. After failing, I asked some of my seniors who were pursuing their PhD then. I seldom used internet those days. For those who aren't ignorant as I was,  here is how I make the EDTA solution.

  • Weigh the appropriate amount of EDTA in a flask.
  • If you are preparing 100 ml of total volume of the solution, add 70 ml water. 
  • Take some ice in a beaker or ice-bucket and place the flask in this.
  • Add one sodium hydroxide (NaOH) pellet and shake the flask intermittently putting it on ice to prevent heating.
  • If NaOH pellet is dissolved completely and EDTA still remains undissolved, add another pellet.
  • Keep on adding one pellet at a time until all of the EDTA is dissolved.
  • Adjust volume to 100 ml (or whatever volume you are making).

The Sigma product information tells that 0.5 M EDTA at pH 8.5 is stable at 4 degree Celsius for months. Also, this solution can be autoclaved.

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