In a recent murder case in Hangzhou, the police used lumino technology to repeatedly wash blood stains to reveal the original shape, even if it was washed with strong acid, it would leave corresponding traces. DNA technology finds tissue DNA particles and blood traces, and other technologies find body tissues with victims’ DNA in pipes and septic tanks. It can be seen that no bloodstain can escape Rumilo's detection.
The luminol reaction is a classic chemiluminescence reaction. It is a yellow crystal or beige powder at room temperature, which is a relatively stable chemical reagent. In forensic medicine, the luminol reaction is also called the aminophthaloyl-hydrazine reaction. It is a chemical reaction that cannot be observed with the naked eye when detected at the crime scene. It can show a very small amount of blood stains (occult blood reaction), even after scrubbing. , Or bloodstains long ago can also be detected by luminol. Biologically, luminol is used to detect the presence of copper, iron and cyanide in cells.
The initial application of luminol reagent was to detect proteins. In western blotting, an enzyme-linked antibody is often used to bind to the protein to be detected, and the combination of luminol chemiluminescence reagent and enzyme (peroxidase) can make local luminescence and reduce the protein The position is displayed.
In addition, luminol derivatives such as isoluminol (ABEI) are labeled on carboxylic acid and ammonia compounds, and then separated by high performance liquid chromatography (HPLC) or liquid chromatography (LC), and then under alkaline conditions It reacts with hydrogen peroxide-potassium ferricyanide to perform chemiluminescence detection, such as labeling the newly synthesized chemiluminescence reagent isoluminol isothiocyanate to yeast RNA, separating it by centrifugation and dialysis, and then performing chemiluminescence detection.
But we should still pay attention to some issues that need to be paid attention to when using luminol and several things that need to be paid attention to when investigating:
1. Luminol fluoresces in the presence of iron, iron-containing alloys, horseradish or certain bleaching agents. Therefore, if the crime scene is thoroughly treated with bleach, the fluorescence from luminol will strongly mask any blood stains.
2. Luminol may interfere with other tests, but luminol does not interfere with DNA extraction.
3. The use of luminol needs to be in a dark environment, so that it is easier to make more accurate judgments with the naked eye.
4. Luminol has a limited amount of time to glow, so you must hurry up to take photos and record.
5. Luminescence lasts for about 30 seconds, which can be observed through long-exposure photos, and the surrounding environment should not be too bright.
In addition to luminol, the chemiluminescence reagents developed by Desheng also include acridine esters and other series. The effect is stable and the quality is guaranteed.
