PressChemical structureIt can be divided into five categories:
①StilbeneType, used in cotton fiber and some synthetic fiber, paper making, soap making and other industries, with blue fluorescence;
②coumarinType, with the basic structure of coumarone, used for celluloidPVC plasticWith strong blue fluorescence;
③PyrazoleLine type, used for wool, polyamideacrylic fibresAnd other fibers, with green fluorescent color;
④ Benzoxynitrogen type, used for acrylic fiber and other fibers andpolyvinyl chloride、polystyreneAnd other plastics, with red fluorescence;
⑤ Benzene dimethylImideType forpolyester fiber, acrylic, nylon and other fibers, with blue fluorescence.
It is usually divided into:
① For detergentFluorescent brightener；②Textile fluorescent whitening agent; ③Fluorescent brightener for paper making; ④Fluorescent whitening agent for plastics and synthetic materials; ⑤Fluorescent whitening agent for other purposes.[1]
The ultraviolet lamp irradiation observation method is to determineFluorescent brightenerThe principle is mainly based on the fact that fluorescent brighteners can not only reflect visible light, but also absorb invisible ultraviolet light. After absorbing the energy of ultraviolet light, they can emit a certain intensity of visible blue purple fluorescence, which can be identified by observing the fluorescence of the sample surface with the naked eye.
2. Whiteness method
Whiteness method mainly adoptsWhiteness testerThe whiteness of the substance is measured. The main working principle of the whiteness tester is to use the integrating sphere to measure the absolute spectral diffuse reflectance, which can be used to analyze whether the sample contains fluorescent whitening agents, and determine the fluorescent whiteness generated by fluorescent emission, that is, whiteness.
Ultraviolet spectrophotometry is a preliminary qualitative, quantitative and structural analysis method based on the absorption characteristics of the substance molecules to the electromagnetic waves in the range of 200~760nm.
Fluorescence spectrophotometry is a method for qualitative or quantitative analysis of substances based on the nature of the longer wavelength characteristic spectrum emitted by substances after absorbing shorter wavelength light energy.
Thin layer chromatographyThin layer chromatographyMethod is a kind of chromatography, which is mainly based on the different physical, chemical and biological characteristics of the separated substances, so that they move at different speeds in a certain matrix for separation and analysis.
Capillary electrophoresis is an analytical method that uses elastic quartz capillary as the separation channel and high-voltage DC electric field as the driving force to separate according to the differences in mobility and distribution behavior of each component in the sample.
7. High performance liquid chromatography
High performance liquid chromatographyThe method is a fast separation method with high accuracy and wide separation range. Its separation principle is mainly based on the difference of distribution coefficient between the stationary phase and the mobile phase of the analyte. It is a relatively mature detection method.
8. Liquid chromatography tandem mass spectrometry
Liquid chromatography tandem mass spectrometry uses liquid chromatography as the separation system,mass spectrumAs a detection system, it has unparalleled sensitivity of other analytical methods, and is more accurate for the structural characterization of compounds.
Doubt about the preliminary test results of whitening agent
A reporter from Guangzhou media randomly selected 7 brands of paper cups from the supermarket, and selected a whole family bucket and a coke cup from a KFC, and sent them toSouth China University of TechnologyDepartment of Food EngineeringThe test results showed that, except for two paper cups that were basically qualified, other samples submitted for test had large blue spot area under the irradiation of the purple light detector. The tester preliminarily judged that the whitening agent was likely to exceed the standard.
International Food Packaging AssociationAccording to an investigation report released, according to medical clinical experiments, once fluorescent substances enter the human body, they may cause harm to the human body. If the dose reaches a certain level, it may also cause cell mutation in the human body, becoming a potential cancer hazard.
In this regard,Kentucky Fried ChickenAspect《Daily Economic News》The statement sent said: "KFC attaches great importance to food safety, and all the paper containers used for food comply with the relevant national standards. About the paper containers used by KFC family barrels."
The Food Packaging Association intervened in the investigation
"We have already started the investigation."International Food Packaging AssociationExecutive Vice President and Secretary GeneralDong JinshiIn an interview with the Daily Economic News, he said that enterprises generally have very strict requirements on paper cups for drinks, but they may ignore paper containers such as family buckets.
On April 22, 2012, the International Food Packaging Association released a survey report on the quality of popcorn barrels in five cinemas in Beijing. The report showed that some popcorn barrels sold in several cinemas containedFluorescent brightener, there may be potential safety hazards.
According to the report, "food gradeWhite cardboard”It is the material used to make popcorn barrel. However, some manufacturers use recycled waste paper to produce popcorn barrel in order to reduce costs. However, because the pulp quality is not up to the standard and the barrel looks whiter, they have to add a lot of fluorescent whitening agents to achieve aesthetic effect.Those popcorn buckets with white appearance may be used in the production processFluorescent brightenerNon food grade paper, i.e“Social white cardboard”。Packaging made of "social white cardboard"UV analyzerIt will show bright and dazzling blue below, "food gradeWhite cardboard”The package made will show natural milky white under the UV analyzer.
"According to relevant regulations,Food wrapping paperThe production enterprise must pass the production license (QS), and no artificial addition is allowedFluorescent brightener。”Dong Jinshi said, "But the actual investigation found that although some production enterprises have QS production licenses, their products have also been detected to contain fluorescent whitening agents, which has serious hidden dangers."
Experts call for improving labeling information
The reporter noticed that fast food enterprises ranged from hamburger wrappers, paper boxes for French fries, paper cups for drinks to packagingpaper bagPaper is indispensable everywhere, but most of these wrappers are not markedQS mark。
In this regard, Dong Jinshi believes that although the national laws and regulations do not mandatorily stipulate that operators must mark the information of the production enterprise and the production license number on the food packaging paper, in order to facilitate consumer tracking and the supervision and management of the relevant departments, operators are urged to mark them.
Dong Jinshi pointed out that the operator or user must obtain the QS certificate from the manufacturer, and if the product is unqualified, the manufacturer shall bear all the responsibilities;However, if the packaging paper without QS certificate is used, both the operator and the manufacturer should bear the responsibility.
The amount of fluorescent whitening agent that may be absorbed by human skin when contacting food packaging paper containing fluorescent whitening agent is 0.001~0.03mg/d.Fluorescent whitening agent will not be absorbed in animals.
2. Dermal allergy
The irritation of various fluorescent whitening agents to the dermis is basically non-existent.
3. Influence of wound healing process
The wound healing process has nothing to do with the use or non use of products such as bandages containing fluorescent whitening agents.
4. Phototoxicity
Fluorescent whitening agent has no effect on human bodyPhototoxicity。
5. Photoallergy
Fluorescent whitening agent has no photosensitivity to human body.
6. Impact of soil
Most papermaking wastewater treatment plants use three-stage treatment technology to transfer the wastewater containing fluorescent brightener to activated sludge, which may be used for filling, soil conditioning or as fertilizer. It is necessary to know the transfer rate of fluorescent brightener in sludge.Therefore, someone asked whether the fluorescent whitening agent in the soil could beBioconcentrationHas been studied.The experiment shows that fluorescent whitening agents are unlikely to be transferred from the sludge to the soil. Fluorescent whitening agents are only found where the sludge is used. At the same time, plants only absorb fluorescent whitening agents on their roots.
effect
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Whitening agent is used to absorb invisible productsultraviolet radiationInto purplish blueFluorescent radiation, and the originalYellow radiationMutualComplementary colorIt becomes white light, improving the whiteness of the product in sunlight.Whitening agent has been widely used in textile, papermakingWashing powder, soap, rubber, plastic, pigment and paint, etc.
As an importantFine chemical products，Fluorescent brightenerIt has a wide range of application fields and good market prospects in industry. Many scientists at home and abroad are committed to the research work of fluorescent whitening agents. The main research direction is to develop fluorescent whitening agents with strong practicability, such as fluorescent fadeless, easily available raw materials, simple synthesis, and pollution-free.
application
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Whitening agents have cyclic conjugated systems in chemical structure, such as:StilbeneDerivativesPhenylpyrazolineDerivativesBenzimidazoleDerivatives, PhenylpyridineAzolDerivativescoumarinDerivativesAnd naphthalimideDerivatives, etc.Among them, the yield of stilbene derivatives is the largest, such as 4,4 '- bis (4,6-DiphenylamineSodium salt of stilbene-2, 2 '- disulfonic acid (triazin-2-amino) is a widely used whitening agent, whose trade name is TA.Such brighteners have been widely used in papermaking, textiles, washing powder, soap and other industries.Whitening agent AD is phenylPyrazoleA derivative of 1 - (p-methylsulfonylphenyl) - 3 - (p-chlorophenyl) pyrazoline, mainly used foracrylic fibresFiber spinning, textiles andplasticIs in production.4-Methyl-7-DimethylamineCoumarin belongs to oxaphthalene orthoketone compounds, which can be used for wool fabricsnylonFabric, soap, detergent and other products.
Largest category in ChinaFluorescent brightenerIt is a liquid brightener for VBL, CXT and paper making.Generally, there are two types of whitening agents, one is water-soluble whitening agent, the other is water-insoluble whitening agent.The former can be used as whitening agent for paper, paint, washing powder and cotton fabric.The latter can be used to whiten chemical fibers, plastics, etc.
Although China's fluorescent brighteners have developed rapidly, compared with the international market, the proportion of the output of fluorescent brighteners in the dye industry is relatively low, and the variety is relatively small.With the development of China's economy and the improvement of living standards, the demand for fluorescent whitening agents will also increase with each passing day, and the output, variety and dosage form will be greatly developed. While increasing the variety in China, special attention should be paid to the development and research of mixed synergistic products, liquid commodities, and low salt environmental protection products, so as to further improve the product quality. On the premise of meeting domestic needs,Expand exports and strengthen competitiveness in the international market.
Flour whitener
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Flour whitenerActive ingredients ofBenzoyl peroxide(BPO), whose scientific name is diluted benzoyl peroxide, was introduced from abroad at the end of 1980s in China and began to be widely used in flourfood additivesThe flour whitening agent is mainly used to bleach the flour and speed up the after ripening of the flour.On March 1, 2011, the Ministry of Health and other departments issued an announcement that since May 1, 2011, the production of benzoyl peroxideCalcium peroxideAt the same time, a reasonable transition period of two months is set.[2]
Fluorescent brightener
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Fluorescent brightener is a kind ofFluorescent dye, or white dye, is also a complex organic compound.Its characteristic is that it can stimulate the incident light to produce fluorescence, so that the dyed material can obtain a glittering effect similar to fluorite, making the material visible to the naked eye very white.[3]
