Blood stain test is one of the most common forensic medical evidence tests in criminal cases. The blood stain developer is used to quickly detect potential blood stains, blood fingerprints, blood fingerprints, etc. at the crime scene, which can quickly restore the crime scene and provide important clues and basis for the investigation of the case. Common blood stain developers include TMB, luminol, and phenolphthalein, which are effective assistants for forensic examination and evidence collection.

TMB, full name 3,3',5,5'-tetramethylbenzidine, CAS number: 54827-17-7. TMB is a new type of safe chromogen reagent, widely used in clinical testing, criminal detection and other fields. The TMB color development method is a more commonly used blood stain test method. Its principle is that the blood contains catalase and hematoporphyrin, which can catalyze hydrogen peroxide to release the initial oxygen, the initial oxygen and tetramethylbenzidine (TMB ) Oxidation reaction will produce tetramethylbenzidine blue, so that the blood stains appear emerald blue.

Luminol, also known as 3-Aminophthalhydrazide , CAS number: 521-31-3. Luminol can have a chemiluminescent reaction with a variety of oxidants, has a high luminescence quantum yield and good water solubility, and has become the most widely used chemiluminescent reagent. Luminol luminescence is a very common method of blood stain detection. Its principle is that blood contains hemoglobin, which contains iron, and iron can catalyze the decomposition of hydrogen peroxide into water and monooxygen, which can oxidize luminol to emit blue-green fluorescence.

Luminol luminescence method is extremely sensitive. Even if criminals have wiped and cleaned the blood on the scene, criminal investigators such as forensics can still rely on Luminol to make the blood stains unscathed. The restoration of blood stains by the Luminol luminescence method is also the most frequent and exciting scene in criminal investigation movies and TV series.

Phenolphthalein, CAS number: 77-09-8. Phenolphthalein is a weak organic acid, colorless in acidic and neutral solutions, purple-red in alkaline solutions, orange in very strong acidic solutions, and colorless in very strong alkaline solutions. And human blood is alkaline, so phenolphthalein can appear red in blood.