The specificity of peroxide to blood stains increases the sensitivity of luminol by 100,000 times

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We all know that luminol is a reagent commonly used in chemiluminescence reagents for detecting blood stains in criminal investigations. Our forensic scientists will spray alkaline solutions containing luminol and hydrogen peroxide or sodium perborate on fabrics, floors or other surface areas suspected of having blood splashed out of the crime. The iron in hemoglobin in the blood catalyzes the reaction of luminol with peroxide, producing blue light, indicating the presence of blood. Forensic researchers can then use a digital camera without a flash to take pictures of the potential bloodstains displayed.


Both peroxide and perborate degrade with low specificity. Even if blood is not present, the presence of other common ions can trigger reactions at the crime scene. Artemisinin is a more critical peroxide. It does not degrade in the presence of other common ions, and only reacts in the presence of blood. This method can distinguish blood from coffee, brown sugar and other stains-luminol can solve these problems.


In addition, the luminol-artemisinin chemiluminescence test is extremely sensitive, even if a criminal or an accomplice tries to wash it away, blood stains can be detected. In fact, even if the dilution of the stain is 100,000 times the original dilution, the new test can still show its presence. The researchers then used smartphones as their tool of choice to capture the resulting luminol images. A smartphone or digital camera with a long exposure setting allows them to capture the glow of activated luminol with a dark background in a dark room.


Replacing the commonly used hydrogen peroxide with the stable organic peroxide artemisinin undoubtedly has advantages in terms of selectivity, robustness and detectability. The effective chemiluminescence reaction allows them to use smart phones with sensitivity and instrument simplicity, which can be easily applied to forensic chemistry and even a wider range of applications.