Chemiluminescence--Luminol

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Chemical Concept Demonstrated

Chemiluminescence

Demonstration

Solution A

Dissolve Na₂CO₃ in distilled water
Add luminol, NaHCO₃, (NH₄)₂CO₃, and CuSO₄ * 5H₂0
Dilute with water

Solution B

Dilute 3%H₂O₂ with distilled water

Pour solutions A and B simultaneously into the funnel.

Observations

The entire spiral gives off a singular glow.

Explanation

Luminol is converted to a dianion in basic solution. This dianion is then oxidized with H₂O₂/Cu²⁺ to form N₂ and an aminophthalate ion in an electronically excited state. In order to achieve an electronically unexcited state, the ion emits a photon of wavelength 424 nm.

Contributors

Dr. George Bodner (Perdue University)