many people have the “stress reaction” of “talking about the color change of fluorescent agents”. indeed, fluorescent agents cause great damage to the skin, but does “detecting a fluorescent reaction” mean that “fluorescent agents have been added”?
let’s learn more about optical brighteners.
what are optical brighteners?
fluorescent whitening agent, also known as fluorescent agent or fluorescent bleach, is a fluorescent dye (white dye) that is mainly used in textile, papermaking, plastics, washing and other industries.
the working principle of fluorescent whitening agent: under the irradiation of ultraviolet light, the fluorescent whitening agent will absorb uv and emit blue fluorescence (about 410-480nm wavelength). in a bright environment, such a fluorescence will appear from it visually offsets the yellow reflection, making the surface of the object look whiter. it is an optical complementary color and brightening.
what are the uses of optical brighteners?
a long time ago, people mainly relied on traditional bleaching and bluing processes to make white items, but they gave people an old-fashioned feel. using fluorescent whitening agents, the whitening effect is unmatched by blue-whitening and chemical bleaching. after that, the application range of fluorescent whitening agents became more and more extensive, starting from the textile industry and gradually developing into food and food contact materials. , cosmetics, paper products, detergents and other industries.
in the food industry, in addition to obvious whitening effects, fluorescent whitening agents also have certain preservation and antiseptic effects. currently, fluorescent whitening agents are not allowed to be added to food. the use of optical brighteners in food contact materials can improve the whiteness and brightness of products, thereby reducing packaging costs.
in the washing and textile products industry, fluorescent whitening agents can restore the visual effect of washed white textiles to a white and bright state, which not only improves the appearance, quality and grade, but also enhances their commercial value. optical brighteners are becoming more and more important.
in the daily chemical industry, my country’s regulations do not explicitly prohibit the use of optical brighteners in daily necessities and cosmetics. adding an appropriate amount of optical brighteners is in compliance with regulations. careful consumers will find that the fluorescent whitening agent “disodium diphenyl disulfonate” is included in the ingredients of some international big-name products.
however, there are also some unscrupulous manufacturers who add excessive amounts of fluorescent whitening agents to facial mask products in order to achieve immediate whitening effects, posing potential safety risks to consumers.
are fluorescent substances called fluorescent whitening agents?
people are often asked if they find fluorescence during the visia test or under the irradiation of a fluorescent pen, and if they suspect that a fluorescent whitening agent is added to the product, they should seek compensation from the merchant.
let me tell you, there is actually no need to be nervous!
how to distinguish between fluorescent reaction and fluorescent whitening agent
fluorescent agents can produce fluorescent reactions, but fluorescent agents are not the only substances that can produce fluorescent reactions.
fluorescence is generated when compound molecules in the ground state absorb energy from ultraviolet or visible light and then electronically transition to a high-energy orbital excited state. a molecule in an excited state transitions to the lowest vibrational energy level of the lowest excited state of the molecule through vibrational relaxation or internal conversion process, and then undergoes a radiative transition back to the ground state, emitting photons to produce fluorescence.
the necessary condition for producing fluorescence is the presence of fluorescent groups in its structure. fluorescent groups are groups containing unsaturated bonds. when these groups are part of the conjugated system of the molecule, the compound may produce fluorescence. common fluorophores include
when the molecular structure contains one or more substituents (such as -oh, -nh2, -cooh), the fluorescence can be enhanced or weakened.
the structural formula of disodium diphenyldisulfonate, a commonly used fluorescent whitening agent in washing and daily chemical products, is as follows:
natural vitamin e has a fluorescent reaction, but is not a fluorescent agent. its molecular structure is as follows:
therefore, those with fluorescent reactions are not necessarily fluorescent whitening agents! !
which ingredients in cosmetics produce fluorescent reactions
it can be seen from the fluorescent reaction groups that there are various substances that can produce fluorescence. substances with fluorescent reactions are commonly found in nature, such as shrimps, crabs, jellyfish, fireflies and other animals; the human body also contains fluorescent substances, mainly amino acids, vitamins, proteins, hormones, etc.; soy sauce, pu’er tea, white wine, black tea, coffee fermented foods can also produce fluorescent reactions.