Ingredients

• Disodium EDTA Dihydrate
• Sodium Hydroxide

Equipment

• Magnetic Stirrer
• pH Meter (freshly calibrated)
• 250mL Volumetric Flask
• 250mL Storage Bottle
• Pasteur Pipette

Step By Step

1. To a 500mL beaker, add 180mL of distilled water and begin stirring.
2. Add 46.525g of NaEDTA to the solution. The EDTA will not dissolve until pH is raised to about 8.0 so don’t worry if it remains cloudy for now.
3. Calibrate pH meter and place probe in stirring solution.
4. Add 18 grams of NaOH to the solution slowly. The EDTA will begin to dissolve and the solution will begin to clarify.
5. Continue to add NaOH until the pH reaches 8.00. Allow the solution to stir a few more minutes and check pH to ensure it reads a stable 8.00.
6. Transfer solution to a 250mL volumetric flask and top off to the 250mL neck mark with distilled water. Invert several times to mix. Look for shimmering to stop indicating complete mixing of water with solution.
7. Transfer to an autoclavable 500mL vessel and autoclave the solution at 121C for 15minutes.
8. Transfer solution to a sterile 250mL storage bottle. Label, date, and store at room temp.

Notes

WEAR PROPER PPE AND EYE PROTECTION WHEN HANDLING HYDROCHLORIC ACID