luminol

Luminol is a synthetic chemiluminescent compound commonly used in forensic science and biochemistry. Its chemical name is 5-amino-2,3-dihydro-1,4-phthalazinedione, and its formula is C8H7N3O2. In alkaline solution, luminol is not luminescent by itself; when it is oxidized in the presence of an oxidant such as hydrogen peroxide and a catalyst, it is converted to 3-aminophthalate in an excited state. Relaxation to the ground state emits blue light, typically with a peak around 425 nanometers.

Applications: The luminol chemiluminescence reaction is widely used to detect trace blood at crime scenes because hemoglobin and other blood-derived peroxidases can catalyze the oxidation. The light emission helps visualize stains that are invisible to the naked eye and may persist for seconds to minutes after application of luminol and activators. The reaction is not specific to blood; other oxidants and catalytic substances can produce luminescence, leading to potential false positives.

In the laboratory, luminol-based chemiluminescence is used as a sensitive reporter system in various assays. It is employed in immunoassays, Western blot detection, and related techniques by coupling luminol emissions to peroxidase enzymes such as horseradish peroxidase.

Safety and handling: Luminol is used as a chemical reagent under standard safety practices. It should be kept away from strong oxidizers, stored in a dry place, and handled with appropriate personal protective equipment in a well-ventilated area.