How to Reduce the Percentage of Peroxide in a Solution

Hydrogen peroxide's oxidizing ability makes it a good topical antiseptic.

Hydrogen peroxide, or H2O2, represents one member of a broad class of compounds called peroxides. It acts as an oxidizer -- a compound that removes electrons from other compounds -- and consequently finds applications in products such as bleach and topical antiseptics. Hydrogen peroxide's reactive nature renders it unstable. When heated for example, it decomposes to water and gaseous oxygen. Hydrogen peroxide also readily reacts with mild reducing agents, or compounds that donate electrons, such as ascorbic acid, also known as vitamin C.

Things You'll Need

• Peroxide test strips
• Sauce pan
• Stove or hot plate
• Vitamin C tablets
• Hammer or other blunt object

Instructions

Peroxide Removal by Boiling

1. Dip a peroxide test strip into the peroxide solution to establish a baseline peroxide level. Match the color of the test strip against the color key provided by the test-strip manufacturer.

2. Pour the peroxide solution into a metal sauce pan and bring it to boiling on a stove or hot plate. Allow the solution to boil for 5 minutes, then remove it from the heat and allow it to cool to room temperature.

3. Test the cooled peroxide solution with another test strip to establish the new peroxide concentration. If you wish to further reduce the peroxide percentage, return the solution to the stove or hot plate and boil for another five minutes, then test again.

Peroxide Removal by Chemical Reaction

1. Dip a peroxide test strip into the peroxide solution to establish a baseline peroxide level. Math the color of the test strip against the color key provided by the test-strip manufacturer.

2. Crush a vitamin C tablet by lightly tapping it with a hammer or other blunt object, then add the crushed tablet to the peroxide solution. With the container open to the atmosphere, swirl the solution for about 5 minutes.

3. Retest the peroxide solution with another test strip. If you wish to further reduce the peroxide percentage, crush an additional tablet, add it to the peroxide solution and swirl for another five minutes. Do not re-cap the peroxide solution for at least 30 minutes to make sure the reaction has stopped producing oxygen.

Tips & Warnings

• Crushing the vitamin C tablet speeds up the dissolution of the tablet, therefore speeding up the reaction.

• If you choose to not crush the tablet, expect the reaction times to take significantly longer.

• You can purchase peroxide test strips online through scientific and industrial supply companies.

• Concentrated peroxide solutions are corrosive to skin and eyes.

• Wear safety goggles and gloves when handling concentrated solutions.

• Never add a vitamin C tablet to a peroxide solution and then re-cap the container.

• The production of oxygen gas pressurizes the container, possibly to the point of explosion.

References

• Purdue University, Department of Chemistry: Oxidizing and Reducing Agents
• New Mexico Institute of Mining and Technology: The Decomposition of Hydrogen Peroxide
• University of North Carolina at Pembroke: Oxygen
• Washington University in St. Louis, Department of CHemistry: Oxidation-Reduction Reactions in Your Lungs

Resources

• Laboratory SOP: Hydrogen Peroxide