This substance can interfere with the luminol reaction

Details:

Luminol is also known as luminescent ammonia, which is a white or yellow crystal powder at room temperature, which is stable. As the saying goes, it is not difficult to see that Lumino is characterized by the word "luminous". Because of the early research found that luminol can produce blue fluorescence after contacting with blood, and then it is used in the detection of blood trace at the scene of crime, and then gradually becomes a common reagent for blood trace display.

In the process of revealing potential blood, cleaning, reagent specificity, blood carrier are all important factors that affect the results. The blood on the spot is often not obvious or undetected by the naked eye because of the suspect's cleaning. Whether various cleaning products in daily life will have an impact on the potential blood trace of blood pre test reagents is a problem worthy of attention.

Washing liquid

The main component of the washing liquid is surfactant, which can effectively reduce the residue of stains on clothes, and thus effectively reduce the amount of blood residue on cotton cloth.

84 disinfectant

84 disinfectant is a common disinfectant and rinse agent, and its main ingredient is hypochlorite. The results show that the fluorescence signal intensity produced by the home rinse agent with hypochlorite can react with luminol, which is difficult to distinguish from blood trace. The results of false positive can be produced by reaction with luminol reagent, which is very similar to human blood, so special attention should be paid to. However, because sodium hypochlorite in the cleaner is easy to decompose and evaporate, the interference effect on luminol reagent can be ignored after the sample is wiped by bleach for 8 hours. Therefore, if time is allowed, it is also an effective method to place blood spot after completely drying, and then test it. At this time, hypochlorite in the test material will be decomposed.

Vegetables containing plant peroxidase

Many vegetables containing plant peroxidase, such as luoxiabu, spinach and some strong oxidizing substances such as rust, can also make hydrogen peroxide decompose and release oxygen free or direct oxidation blood trace reagent to make it discolor. This led to a decrease in the specificity of the blood mark pre test reagent. Although white radish and spinach have some color reaction, it shows that spinach juice and radish juice can cause false positive reaction at the crime scene, but the color and speed of color can not reach the same color level of blood. It shows that the amount of plant peroxidase in these fruits and vegetables can not cause strong chemiluminescence reaction, but only some light color (brightness) changes. The main component of rust is iron trio3, which can make the reagent of blood trace display produce obvious false positive reaction.

Luminol has high sensitivity and specificity, can detect the NAK level of trace blood, but it will also be interfered by other substances, but luminol will not affect the subsequent DNA detection, so it can be detected if it is blood or other conditions after the detection of light.