Difference between EDTA - Chemists Corner

Formulating

Difference between EDTA

Posted by ZivBA on October 15, 2018 at 6:12 am

What is the difference between Di-Sodium EDTA and Tri-Sodium EDTA?

And how it impact the formulation?

Thanks.

ZivBA replied 6 years ago 4 Members · 8 Replies
8 Replies

em88

Member
October 15, 2018 at 7:23 am

As the name says it, trisodium EDTA has one Na+ more. It has a pH slightly higher compared to disodium EDTA
chemicalmatt

Member
October 17, 2018 at 4:42 pm

This is a chemistry question ZivBA. Look into Formation Constants for multivalent metal ions with various sequestrants. Then there are Chelation Values to be researched for these sequestrants. These differ for each ion at different pH ranges. The “tri” sodium EDTA is less effective than “di” for most common ions when the pH is lower than 8.0. Generally, “Tetra” works best for all formulations above pH 7.0.
ZivBA

Member
October 21, 2018 at 4:48 am

Thank you em88 for the obvious.

Dear chemicalmatt , Actually it’s a Formulation question, I want to know if there is a difference between them in a formulation?

Why to use Di or Tri in a formulation?

Is There a big difference? How it’s impact the formulation?

Should I look for something else before using one of them?

Thanks.
chemicalmatt

Member
October 21, 2018 at 10:23 pm

Should make little difference in your formulation as long as you aren’t using an electrolyte-sensitive rheology agent - like Carbopol, for instance. That’s why the disodium EDTA is so common.
em88

Member
October 22, 2018 at 7:30 am

ZivBA said:

Thank you em88 for the obvious.

Dear chemicalmatt , Actually it’s a Formulation question, I want to know if there is a difference between them in a formulation?

Why to use Di or Tri in a formulation?

Is There a big difference? How it’s impact the formulation?

Should I look for something else before using one of them?

Thanks.

I’m almost certain that you are not sure what information do you need exactly.
First you have to know the pharmaceutical form and application. (guessing is topical).
Second, look for incompatibilities with the other ingredients.
Third, function.
Both are chelating agents, the biggest difference is the pH these salts induce to your preparation. Disodium EDTA has a pH 4-6 while trisodium EDTA around 9. Also trisodium EDTA is more soluble in water.

Why not simply list your ingredients and get a more precise help?
ZivBA

Member
October 22, 2018 at 8:42 am

chemicalmatt Thank You Very Much!!!
ngarayeva001

Member
October 23, 2018 at 9:19 pm

Suppliers recommend using disodium EDTA in lower pH products and products where clarity is not important. I mostly see it in lotions. Tetrasodium EDTA is recommended for surfactant products and clear gels. I have not seen trisodium a lot though. But my understanding is that the difference isn’t crucial.
ZivBA

Member
October 24, 2018 at 8:16 am

ngarayeva001 Thank you!!!

Very Helpful!!!