Luminol

Luminol is a chemical used by forensic investigators to detect blood.

• formula:C₈H₇N₃O₂
• CAS number: 521-31-3

Synonyms

• 5-Amino-2,3-dihydro-1,4-phthalazinedione [521-31-3]
• o-aminophthaloyl hydrazide
• o-aminophthalyl hydrazide
• 3-Aminophthalhydrazide
• 3-aminophthalic hydrazide
• Luminol

Use by Crime Scene Investigators

Theory

Luminol is used by investigators to locate blood, even if it has been cleaned or removed. Using its natural property of chemiluminescence, it fluoresces under a certain wavelength of light if blood is present. The glow lasts for about 30 seconds and is blue. Luminol reacts with the iron in haemoglobin, a pigment present in blood.

Drawbacks

Nevertheless, Luminol has drawbacks that can keep it from detecting just blood that has been shed in a crime:

• Luminol also flouresces in the presence of copper or an alloy of copper, certain bleaches and horseradish.

• Luminol will also detect the small amounts of blood present in urine and it can be distorted if animal blood was present in the room that is being tested.

• Luminol presence may prevent other tests to be performed on a piece of evidence.

• Luminol is listed as possible carcinogen but has not yet been proven as such.

Other Uses

• Medical: Used to conduct biochemical assays
• Amusement: Glowing light sticks
• Education: Getting young people interested in science

External links

• Synthesis of Luminol
• Technical note about Hemaglow™
• HowStuffWorks "How Luminol Works"