Does Luminol reagent react when encountering saliva?

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Luminol reagent, also known as aminobenzoyl hydrazine, is an important tool in the fields of chemistry and criminal investigation, with its unique feature being luminescence reaction. In the early years, researchers discovered that it can emit blue light after oxidation. After continuous exploration, they attempted to test blood stains and cleverly discovered that it can serve as a tracer reagent for criminal investigation to assist in detecting crime scenes. No matter how long the bloodstains on site are cleaned and rubbed, they can identify the presence of blood cell components. This breakthrough has instantly elevated the status of Luminol, but at the same time, some people have raised the question of whether Luminol reacts to human saliva? Let's take a look together.

luminol reagents

1、 Lumino's Luminescence Principle

Although luminol reagents are widely used in laboratories and criminal investigation, they usually do not undergo a luminescence reaction when in contact with saliva, because the chemical mechanism of luminol luminescence is incompatible with the composition of saliva. Luminol is an organic molecule with strong fluorescence, and its luminescence principle is based on a chemiluminescence reaction. This chemical reaction requires a reaction with an oxidant (usually hydrogen peroxide) in an alkaline environment, and also requires the catalytic action of transition metal salts such as iron, copper, cobalt, etc.

2、 Luminol's Luminescence Process

Firstly, Luminol reacts with sodium hypochlorite (NaClO) under alkaline conditions to form a luminescent intermediate. This step is the initial stage of the luminescent reaction, and then hydrogen peroxide (H2O2) reacts with the intermediate generated in the previous step, causing Luminol to release blue light. The principle of its luminescence is based on the generation and elimination of excited state intermediates. When Lumino molecules are oxidized, the generated intermediates release energy when returning to the ground state. This energy is expressed in the form of photons, resulting in visible blue light.

3、 Reaction between Luminol Reagent and Saliva

Saliva is a biological liquid that contains water, enzymes, proteins, and other components. Although saliva is a living liquid, its composition does not match the alkaline and oxidizing conditions required for luminol luminescence reaction. Therefore, when luminol reagent comes into contact with saliva, it usually does not trigger a luminescence reaction. And the main components in saliva are water, mixed enzymes, mucus, and some ions, which are not included in the reagents required for luminol luminescence reaction.

luminescence reaction

Due to the mismatch between the chemical composition of saliva and the alkaline and oxidizing conditions required for luminol luminescence reaction, researchers usually do not use saliva samples to trigger luminol reagent luminescence reaction in laboratory or medical diagnosis. As an advantageous manufacturer of chemiluminescent reagents, Desheng can supply Luminol raw powder with high sensitivity and stable luminescence. Due to direct sales by the manufacturer, the price is discounted. If you are interested, please feel free to contact us for purchase!