Detecting Fake Blood with Luminol

Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★☆ Some safety precautions required to perform safely

Categories: Catalysts, Forensics

Alternative titles: Luminol Detection of Blood-Meal Stains

Summary

A luminol solution (luminol + sodium hydroxide + hydrogen peroxide) can be used to reveal “fake” blood stains made from blood meal fertilizer. The demo compares a control surface to areas stained with a blood-meal slurry and documents the chemiluminescent glow in the dark.

Procedure

Mix blood meal with a little water and apply as fake blood stains on a surface; let dry slightly.
Prepare a luminol solution with sodium hydroxide and hydrogen peroxide.
Darken the room and spray or drip the luminol solution onto the stains.
Observe the blue glow and compare it to an unstained control area.
Record or photograph results before the glow fades.

Links

Luminol Experiments, Blood Detection, Fake Crime Scene Cleanup - sdriza:

Variations

Purchase a commercially available luminol kit.
Test different amounts of blood meal.
Compare glow on porous vs. nonporous surfaces.

Safety Precautions

Wear gloves and goggles.
Use only dilute sodium hydroxide and 3% hydrogen peroxide.
Do not mix luminol with bleach or ammonia.
Handle blood meal carefully; avoid dust and wash hands afterward.

Questions to Consider

Why does blood meal make luminol glow? (It contains iron, which catalyzes the reaction.)
How does stain size or freshness affect the glow?
What other everyday substances might cause false positives?