Difference Between Disodium EDTA and Tetrasodium EDTA

The key difference between disodium EDTA and tetrasodium EDTA is that disodium EDTA has a pH lower than 7 while tetrasodium EDTA has a pH greater than 7.

EDTA is a chelating agent. Therefore, it has the potential to bind with metal ions such as calcium and magnesium. EDTA stands for Ethylenediaminetetraacetic acid. It results in sequestration of metal ions. Accordingly, EDTA binds with metal ions and forms a stable EDTA metal complex. Furthermore, there are two forms of EDTA namely disodium EDTA and tetrasodium EDTA. Both types are sodium salts of EDTA. Disodium EDTA contains 2 sodium cations while tetrasodium EDTA contains 4 sodium cations per molecule.

CONTENTS

1. Overview and Key Difference
2. What is Disodium EDTA
3. What is Tetrasodium EDTA
4. Similarities Between Disodium EDTA and Tetrasodium EDTA
5. Side by Side Comparison – Disodium EDTA vs Tetrasodium EDTA in Tabular Form
6. Summary

What is Disodium EDTA?

Disodium EDTA is a form of EDTA with two sodium cations. It is a heavy metal chelating agent and present as a dry powder. The general structure of EDTA contains four negatively charged oxygen atoms. Out of the four, two oxygen atoms of EDTA remain combined with two sodium cations to form disodium EDTA. Therefore, disodium EDTA is a synthesized byproduct of EDTA. Its molecular mass is about 336.2 g/mol.

Ethylenediamine, formaldehyde and sodium cyanide participate in the synthesis of EDTA. Therefore, the sodium cyanide is the source of sodium ions present in disodium EDTA. The pH of disodium EDTA ranges between 4-6. However, it does not exceed pH 7.

Disodium EDTA is added in minute concentrations to cosmetic products including shampoos to increase shelf life and foaming properties. Therefore, disodium EDTA is present in the products that we use in our day to day lives such as shampoos, hair dyes, shower gels, lotions, etc. It also has a use in clinical therapeutic such as chelation therapy and anticoagulation. Furthermore, disodium EDTA is a good preservative as well.

What is Tetrasodium EDTA?

Tetrasodium EDTA is a form of EDTA with four sodium cations. All four negatively charged oxygen atoms of EDTA are bonded to four sodium cations to form tetrasodium EDTA compound. Similar to disodium EDTA, Tetrasodium EDTA is a by-product of EDTA synthesis process. The molar mass of tetrasodium EDTA is 380.1 g/mol. It is a colourless compound available in both dry powder and liquid form. Tetrasodium EDTA is slightly soluble in ethanol. Its pH ranges from 10-11.

Tetrasodium EDTA is applied at industrial scale as a water softener and a preservative. Similar to disodium EDTA, it has a use in manufacturing cosmetics and personal care products. Tetrasodium EDTA has a higher potential in sequestration of metal ions. It binds with metal ions and prevents the reaction of metal ions with other ingredients of the product. Therefore, the addition of it increases the product shelf life.

What are the Similarities Between Disodium EDTA and Tetrasodium EDTA?

• Both compounds are sodium salts of EDTA and are byproducts of EDTA synthesis process.
• They are used as preservatives, personal care products and cosmetics.
• Also, both Disodium EDTA and Tetrasodium EDTA results in sequestration of metal ions.

What is the Difference Between Disodium EDTA and Tetrasodium EDTA?

Disodium EDTA and tetrasodium EDTA are two forms of EDTA. The key difference between disodium EDTA and tetrasodium EDTA is the pH value of each compound. The pH of disodium EDTA ranges between 4 and 6 while the pH of tetrasodium EDTA ranges between 10 to 11. Furthermore, disodium EDTA has two atoms of sodium while tetrasodium EDTA has four atoms of sodium. Thus, it is also a difference between disodium EDTA and tetrasodium EDTA.

Moreover, we can also identify a difference between disodium EDTA and tetrasodium EDTA based on their molecular masses. The molecular mass of disodium EDTA is 336.2 g/mol while the molecular mass of tetrasodium EDTA is 380.1 g/mol.

Summary – Disodium EDTA vs Tetrasodium EDTA

EDTA is Ethylenediaminetetraacetic acid. It results in sequestration of metal ions. It binds with metal ions and forms a stable EDTA metal complex. Accordingly, the two forms of EDTA are disodium EDTA and tetrasodium EDTA. The key difference between disodium EDTA and tetrasodium EDTA is that disodium EDTA has a pH lower than 07 while tetrasodium EDTA has a pH greater than 07. Furthermore, disodium EDTA contains 2 sodium cations while tetrasodium EDTA contains 4 sodium cations per molecule. Both compounds are sodium salts of EDTA and are byproducts of EDTA synthesis process. Thus, this summarizes the difference between disodium EDTA and tetrasodium EDTA.

Reference:

1. Amara. “Disodium EDTA: What You Need To Know •.” BambooCore Fitness, 20 Nov. 2018. Available here  
2. “Edta: Uses, Side Effects, Interactions, Dosage, and Warning.” WebMD, WebMD. Available here  

Image Courtesy:

1.”Disodium EDTA”By Andel (talk) – Own work, (Public Domain) via Commons Wikimedia 
2.”Tetrasodium EDTA”By User:Edgar181 – Own work, (Public Domain) via Commons Wikimedia