Substances with the above properties are called fluorescent agents. Therefore, fluorescent agents are not a specific substance, but a general term for a class of substances. The emitted light emitted by fluorescent agents after absorbing light energy is located in the visible light band, and can present a variety of colors. In daily life, fluorescent whitening agents commonly used by people are stilbene derivatives. Its characteristic is that it absorbs ultraviolet light and reflects blue-white phosphorescence. White goods in life can slightly absorb blue light in visible light, resulting in insufficient blue light, which makes the goods slightly yellow, which affects the appearance of products. If fluorescent whitening agent is added to white products, its absorption of ultraviolet light will be converted into blue outgoing light, which will complement the yellow color of the products themselves, and the products seen by naked eyes will be whitened, which is why manufacturers add fluorescent whitening agents.

Then, will the articles added with fluorescent whitening agents in our daily life do harm to our health? Scientific research shows that fluorescent agent is not easily degraded after being absorbed by human body, and once it is combined with protein in human body, it can only be excreted through liver decomposition. According to medical clinical experiments, fluorescent agent can make cells mutate and may become a potential carcinogenic factor.  However, the products added with fluorescent agents generally do no harm to human body. China has a clear regulation on the addition of fluorescent agents: migratory fluorescent substances should not be detected in daily necessities. "Migratory fluorescent substances" means that the added fluorescent substances will be transferred to human skin or mucosa through washing, biting, sweating or touching.

Therefore, when fluorescent whitening agents are detected with purple flashlight in daily life, there is no need to panic. Products that meet the national regulations do not have fluorescence migration, and fluorescent whitening agents will not migrate to human body, thus causing no harm to human body.