By Dan Taylor, updated March 24, 2022

Ethylenediaminetetraacetic acid (EDTA) is a colorless chelating agent approved by the U.S. Food and Drug Administration for treating heavy‑metal poisoning, hypercalcemia, and ventricular arrhythmias. To prepare a clear aqueous solution, follow these simple steps.

Step 1: Prepare the Diluent

Measure 80 mL of distilled water into a clean, dry beaker.

Step 2: Neutralize the Acid

In a separate container, weigh 18.6 g of anhydrous EDTA. Add 2.2 g of sodium hydroxide pellets (or the equivalent volume of a concentrated NaOH solution). The NaOH will raise the pH to approximately 8.0, creating the optimal environment for EDTA to dissolve.

Step 3: Combine and Stir

Slowly pour the EDTA‑NaOH mixture into the water while stirring with a magnetic stirrer. Continue vigorous stirring until the solution turns clear, indicating complete dissolution.

Materials Required

• 18.6 g anhydrous EDTA
• 2.2 g sodium hydroxide pellets (or equivalent in concentrated NaOH solution)
• 80 mL distilled waterMagnetic stirrer with stir bar

Following these steps ensures a homogenous EDTA solution that can be safely used for clinical or laboratory applications.