Preparation of 1 mM EDTA solution from stock solution of EDTA (0.5M, pH 8.0)

Overview

• EDTA (Ethylenediaminetetraacetic acid) is a chelating agent. Due to its ability to sequester metal ions such as Mn²⁺, Ca²⁺, Mg²⁺ and Fe³⁺, EDTA is widely used in a number of cell and molecular biology experiments.
• Metal ions are necessary for the activity of many enzymes (e.g., DNases and DNA modifying enzymes) as well as interactions of biomolecules (e.g., receptor-ligand interaction). Sequestration of metal ions disrupts metal ion-dependent interactions (e.g., cell-cell and cell substratum interaction) as well as inhibits the action of metal ion-dependent enzymes.
• Here we describe steps to prepare 1 mM EDTA solution from stock EDTA solution.

Requirements

Reagents
> 0.5 M EDTA solution, pH 8.0 at 25°C
> Deionized / Milli-Q water

Equipment and disposables
> Measuring cylinder

Composition:
1 mM  EDTA, pH 8.0 at 25°C

Objective:
Preparation of 100 ml of 1 mM EDTA solution (pH 8.0) from 0.5 M EDTA solution (pH 8.0)

Preparation:

Step 1: Calculate the amount of 0.5M EDTA required for the preparation of 100 ml of 1 mM EDTA.
You need to add 0.2 ml of 0.5 M EDTA in 99.8 ml water to achieve 100 ml of 1 mm EDTA solution. (See calculation)

Step 2: Take ≈50 ml water in a measuring cylinder and add 0.2 ml of 0.5M EDTA in it.

Step 3: Adjust the final volume 100 ml with deionized/Milli Q water. Mix it.
Tip: To mix, you can cover the measuring cylinder with parafilm and mix the solution by inverting the measuring cylinder 3 – 4 times. Take care no solution leaks out during this process. Alternatively, you can transfer the solution to a storage bottle and mix by swirling the bottle or using a magnetic stirrer.

Storage
Transfer solution to a storage bottle. You can store the solution at room temperature. The solution is stable at room temperature for a long time.