Making a Luminol Glowstick

Pretty much everyone has played with a glowstick, but how exactly do they work?

Well, a glowstick relies on the principal of Chemiluminescence, which is the generation of electromagnetic radiation in the form of light by the release of energy from a chemical reaction. In chemistry, chemiluminescent reactions typically involve the fragmentation (breaking) of a weak O₂ bond (like those found in all peroxides) to release a large amount of energy. This energy is then transferred to a substrate chemical (Luminol) which absorbs the energy and releases a photon, producing light.

Our glowstick experiment uses four chemicals as shown below. The Luminol (C₈H₇N₃O₂) and Hydrogen Peroxide (H₂O₂) are the two key parts, the Potassium Hydroxide (KOH) helps get the Luminol into solution while the Sodium Ferrocyanide (Fe(CN)₆) acts as a catalyst. We will be creating two different solutions which will act as the two parts of the glowstick.

Chemicals / Materials Required:

• 5 grams Potassium Hydroxide (KOH)
• 0.1 grams Luminol (C₈H₇N₃O₂)
• 10 mL Hydrogen Peroxide (H₂O₂)
• 0.25 grams Sodium Ferrocyanide (Fe(CN)₆)
• Hotplate or bunsen burner with stand
• 1 L beaker and a 50 mL beaker
• Scale and weighing tray
• Gloves and safety glasses

Solution A:

1. Heat one-liter (1 L) of H₂O in a beaker to approximately 150 °F to facilitate dissolving the ingredients into solution.
2. Combine 5 grams (g) of Potassium Hydroxide (KOH) and 0.2 g of Luminol into the beaker containing 1 L of H₂O.
3. Thoroughly stir until all chemicals are dissolved into solution.

Solution B:

1. In a separate 50 mL beaker measure out 10 mL of Hydrogen Peroxide (either 3% or 30% depending on the desired rate of reaction).
2. Combine the H₂O₂ with 0.25 g of Sodium Ferrocyanide.

 Photos of the preparation are shown below.

The Ingredients in a Glowstick	Weighing 5 g of KOH	A Sample of Luminol (C8H7N3O2)
Measuring 0.1 g of Luminol	Adding KOH and Luminol to Solution	Measuring 10 mL H2O2
Adding Fe(CN)6 to H2O2	The Finished Catalyst Solution	The Two Parts of a Glowstick

 

Once everything is ready, we can activate the glowstick by combining the two solutions as shown in the video below. Since we only used a scant amount of Luminol and 30% hydrogen peroxide, the reaction proceeds rapidly and produces an eerie blue glow.

 

Video of the Luminol Reaction

 

The two photos below show the result of the above reaction as well as a second trial using a much more concentrated Luminol solution on a hot plate and some food coloring for effect.

 

The Luminol Reaction from Above	A Modified Version of the Experiment