(/)
This substance, used by the police to detect traces of blood, causes a reaction called chemiluminescence. Roughly speaking, this “swear word” describes a chemical reaction that releases energy in the form of light. Luminol is a powder – made up of carbon, hydrogen, oxygen and nitrogen atoms – which is diluted in hydrogen peroxide.
This solution, when sprayed on suspicious sites, reacts in contact with the iron present in blood hemoglobin and releases a bluish light, strong enough to be seen in the dark. “An excitation is chemically produced in a chemical element. In the case of luminol in contact with iron, that element is oxygen,” says forensic biologist Mark Benecke, from International Forensic Research & Consulting, a forensic research organization in Germany. Below, we explain the details of this reaction.
time to give birth
Chemical reaction reveals hidden clues at a crime scene
1. A police expert arrives at a suspect’s home. With the naked eye, he doesn’t see any signs of blood — the killer cleaned the carpet in the house where he killed the victim. However, even after cleaning, in the middle of the carpet fibers, blood molecules are hidden
2. After doing a complete sweep of the site, the expert sprays the luminol solution with hydrogen peroxide at the points where he thinks there may be traces of blood. This procedure is the last to be performed by the forensic specialist as the luminol can destroy other evidence.
3. When drops of luminol solution come into contact with iron in blood hemoglobin, nitrogen (N) and hydrogen (H) atoms escape from the luminol molecules. On the other hand, the solution begins to capture oxygen atoms (O) from the blood
4. The electrons of oxygen atoms are agitated by the exit of nitrogen and hydrogen. The energy of this movement of electrons is dissipated in the form of luminous particles. The result is a bluish light that identifies where traces of blood are. The suspect is screwed!