Can old bloodstains also be detected with luminol 521-31-3?

In the field of criminal investigation, blood stain analysis is the key link to restore the truth of the case and lock the suspect. However, criminals often meticulously clean up the scene, attempting to erase all evidence, especially those old bloodstains that are difficult to detect with the naked eye. At this moment, a chemical reagent called luminol became a trusted assistant to forensic experts, capable of revealing the truth behind bloodstains hidden under the dust of time.

1, Old Blood Stain Detection: Luminol's Outstanding Performance

Old bloodstains, due to their age, often have undergone chemical reactions with the surrounding environment, resulting in darker colors, blurred shapes, and even complete dryness. However, none of these can escape Luminol's "eye of law". The principle of using luminol to detect blood is that hemoglobin in the blood contains iron, which can catalyze the decomposition of hydrogen peroxide into water and monooxygen. Monooxygenate luminol to produce blue-green fluorescence. This process is extremely sensitive and can detect blood with a concentration of only one millionth, even a small drop of blood can be detected in a large tank of water. Therefore, even if bloodstains have been present for several years, as long as there are trace amounts of hemoglobin remaining, luminol can reveal their true form.

luminol powder

In practical operation, forensic experts will evenly spray the prepared luminol solution on the area to be tested, then turn off the light source and observe the fluorescence reaction. If there are bloodstains in the area to be tested, the luminol solution will produce strong blue fluorescence in these areas. By observing the intensity and distribution of fluorescence, the presence and distribution range of bloodstains can be preliminarily determined. This method is not only suitable for hard surfaces such as floors and walls, but also for items with strong adsorption properties such as clothing and bedding.

2, Limitations and coping strategies of luminol

Although luminol performs well in detecting old bloodstains, it also has certain limitations. Firstly, luminol cannot distinguish between human blood and animal blood. If there are pets on site, their urine or excrement can also trigger a luminol reaction, leading to false positive results. Secondly, the luminol reaction may be affected by environmental factors, such as the presence of oxidants such as bleach and hypochlorous acid, which may mask or interfere with the fluorescence reaction of bloodstains.

To overcome these limitations, forensic experts will adopt a series of coping strategies during the testing process. For example, before spraying luminol solution, the site will be dried to reduce the interference of oxidants such as bleach. At the same time, combined with other detection methods such as aniline test, DNA analysis, etc., further verification and confirmation of suspected bloodstains are carried out.

3, Luminol: A Powerful Assistant in Criminal Investigation

The application of luminol in criminal investigation not only improves the sensitivity and accuracy of bloodstain detection, but also provides key clues for case investigation. It can help forensic experts reconstruct the process, location, and other information of a case. In many complex cases, the luminol reaction has become the key and breakthrough point in solving them.

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Hubei Xindesheng Material Technology Co., Ltd. specializes in the production of chemiluminescence reagents such as luminol. With advanced production equipment and rich production experience, our professional technical team ensures product quality and can provide good after-sales service and customized services. If you have any related procurement needs in the near future, please click on the official website for more details or contact me directly!