What Should I Know about Melamine in Baby Formula?

Melamine (sn jù qíng àn) (English: Melamine) (chemical formula: C3N3 (NH2) 3), commonly known as melamine, protein, IUPAC named "1,3,5-triazine-2,4,6-triamine ", Is a triazine nitrogen-containing heterocyclic organic compound, which is used as a chemical raw material. It is a white monoclinic crystal, almost odorless, slightly soluble in water (3.1g / L normal temperature), soluble in methanol, formaldehyde, acetic acid, hot ethylene glycol, glycerol, pyridine, etc., insoluble in acetone, ethers, and harmful to the body. Harmful and should not be used in food processing or food additives.

On October 27, 2017, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization initially compiled the reference, and melamine was in the list of 2B carcinogens. ^[1]

Chinese name: Melamine
English name: Melamine
nickname: Melamine, protein, melamine;
Chemical formula: C3H6N6
CAS Registry Number: 108-78-1
EINECS registration number: 203-615-4

Melting point: 354 ° C (523 K)
Boiling point: sublimation
Water soluble: 3.1g / L, 20 ° C
Density: 1.574 g / cm3
Exterior: White monoclinic crystal
Application: Melamine resin

Physicochemical Properties of Melamine

Melamine physical properties

Melamine structural formula Appearance and properties: white, monoclinic crystal.

Decomposed at 354 ° C.

Melting point (° C):> 300 (sublimation)

Relative density (water = 1): 1.573316

Relative vapor density (air = 1): 4.34

Saturated vapor pressure (kPa): 6.66

Solubility in water (20 ): 0.33g

Solubility: Insoluble in cold water, soluble in hot water, slightly soluble in water, ethylene glycol, glycerin, (hot) ethanol, insoluble in ether, benzene, carbon tetrachloride.

Melamine Properties

Non-flammable, stable in nature at room temperature. Aqueous solution

It is weakly alkaline (pH = 8), and can form melamine salt with hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, etc. Under neutral or slightly basic conditions, various methylolmelamines are condensed with formaldehyde, but in slightly acidic (pH 5.5-6.5) polycondensation reactions with methylol derivatives generate resin products. When it is hydrolyzed by a strong acid or a strong alkaline aqueous solution, the amine group is gradually replaced by a hydroxyl group, firstly generating cyanuric acid diamide, further hydrolyzing to form cyanic acid monoamide, and finally generating cyanuric acid.

Melamine Mass Spectrum

In the figure, the abscissa represents the mass-to-charge ratio (m / z) of the ion, and the value of the mass-to-charge ratio increases from left to right. For ions with a single charge, the value represented by the abscissa is the mass of the ion;

Mass spectrum

Melamine Safety Terms

S36 / 37Wear suitable protective clothing and gloves.

Wear suitable protective clothing and gloves.

Preparation method of melamine

It is obtained by reacting dicyandiamide with ammonia in a methanol solvent at 200 ° C. This method requires 1,180 kg of dicyandiamide (98%) and 30 kg of liquid ammonia per ton of product. Compared with this method, the urea method is low in cost and more commonly used. Urea uses ammonia as a carrier and silica gel as a catalyst. It boils at a temperature of 380-400 ° C. It first decomposes to form cyanic acid, and further condenses to form melamine. The resulting triamine gas is cooled and trapped to obtain a crude product, which is then dissolved to remove impurities and recrystallized to obtain a finished product. Urea production of melamine consumes about 3800 kg of urea and 500 kg of liquid ammonia per ton of product.

Melamine market development

Melamine uses urea as a raw material, and it takes about 3 tons of urea to produce 1 ton of melamine. China is the world's largest urea producer, with large urea production and low prices. Even under the background of the country's implementation of high tariffs to curb urea exports, the annual urea export volume still reaches (300 to 7 million tons). The rich urea resources make China Melamine production has unique advantages. The serious expansion of China's melamine capacity has led to fierce competition among Chinese melamine enterprises and weak price increases in the industry.

Main uses of melamine

Condensation polymerization with formaldehyde can be used to prepare melamine resin, which can be used in the plastics and coatings industry, and can also be used as an anti-folding and anti-shrinking agent for textiles. The modified resin can be used for bright color, durable and good hardness metal coatings. It can also be used for strong, heat-resistant decorative sheets, moisture-proof paper and gray leather tanning agents, adhesives for synthetic fire-resistant laminates, fixatives or hardeners for waterproofing agents, etc. 582 melamine resin prepared from melamine, formaldehyde and butanol as raw materials. Used as a leveling agent for solvent-borne polyurethane coatings.

The main raw material for the manufacture of melamine formaldehyde resin is used as an organic element analysis reagent. It is also used in the synthesis of organic and resin as a tanning agent and filler for leather processing. Condensation polymerization with formaldehyde can be used to prepare melamine resin, which can be used in the plastics and coatings industry, and can also be used as an anti-folding and anti-shrinking agent for textiles. The modified resin can be used for bright color, durable and good hardness metal coatings. ^[2]

^[3] Melamine resin made by condensation polymerization with formaldehyde is widely used in the manufacture and processing of wooden building templates. It can be used for waterproofing the surface of the template and the adhesion of the wood core board, increasing the number of times the template is reused.

Notes on melamine

Hazardous properties of melamine

Health hazard: No occupational poisoning has been reported. Note that this product can decompose at high temperatures to produce highly toxic cyanide gas.

Explosion hazard: The product is non-combustible.

First aid measures for melamine

Skin contact: Remove contaminated clothing and rinse with plenty of running water.

Eye contact: Raise eyelids and rinse with running water or saline. Seek medical attention.

Inhalation: Remove from the scene to fresh air. Seek medical attention.

Ingestion: Drink plenty of warm water and induce vomiting. Seek medical attention.

Melamine fire protection measures

Hazardous characteristics: Heat releases highly toxic cyanide gas.

Hazardous combustion products: carbon monoxide, carbon dioxide, nitrogen oxides, hydrogen cyanide.

Fire extinguishing methods: Firefighters must wear filter respirators (full face masks) or isolated respirators, wear full-body fire and gas protective clothing, and extinguish fires in the upwind direction. Move the container from the fire to the open space as much as possible.

Melamine leak treatment

Emergency treatment: Isolate leaking contaminated areas and restrict access. It is recommended that emergency handlers wear dust masks (full-face masks) and wear protective clothing. Collect dry, clean, covered containers with a clean shovel and transfer to a safe place. If there is a large amount of leakage, collect it for recycling or transport it to a waste disposal site for disposal.

Disposal of Melamine

Precautions for operation: airtight operation and comprehensive exhaust. Operators must be specially trained and strictly abide by the operating procedures. It is recommended that operators wear self-priming filter dust masks, chemical safety protective glasses, anti-poison infiltration overalls, and rubber gloves. Avoid generating dust. Avoid contact with oxidants and acids. Handle with care when handling to prevent damage to packaging and containers. Equipped with leakage emergency treatment equipment. Empty containers may be harmful residues.

Storage precautions: Store in a cool, ventilated warehouse. Keep away from fire and heat sources. It should be stored separately from oxidants and acids. The storage area should be equipped with suitable materials to contain spills.

Melamine risk terminology

R20 / 21Harmful by inhalation and in contact with skin.

Harmful by inhalation and in contact with skin.

R44Risk of explosion if heated under confinement.

Risk of explosion if confined heating.

Melamine Limit

Chinese Standard for Melamine

On April 6, 2011, "Announcement on the Limit Value of Melamine in Food": Melamine is not a food raw material or a food additive, and it is forbidden to be artificially added to food. Those who artificially add melamine to food shall be investigated for legal responsibility according to law. As a chemical raw material, melamine can be used in the production of plastics, coatings, adhesives and food packaging materials. Data show that melamine may enter the food from the environment, food packaging materials, etc., and its content is very low. In order to ensure human health and food safety, according to the Food Safety Law and its implementing regulations, on the basis of summing up the implementation of the Temporary Management Limit Value of Melamine in Milk and Milk Products (Announcement No. 25 of 2008), taking into account The Codex Committee has proposed a limit for melamine in food, and specifically formulated a limit value for melamine in food in China. The announcement is as follows:

The limit value of melamine in infant formula is 1mg / kg, and the limit value of melamine in other foods is 2.5mg / kg. Foods above the limit shall not be sold.

The above provisions shall be implemented as of the date of issuance. The Announcement on the Temporary Management Limit Value of Melamine in Milk and Milk Products (Announcement No. 25 of 2008) was repealed simultaneously ^[4] .

Melamine International Standard

On July 2, 2012, the 35th Session of the Codex Alimentarius Commission reviewed and approved the melamine limit standard for liquid infant formula, specifically: the melamine limit for liquid infant formula is 0.15mg / kg. ^[5]

On July 5, 2012, the United Nations Codex Alimentarius Commission responsible for setting food safety standards set new standards for melamine content in milk. In the future, the melamine content per kilogram of liquid milk should not exceed 0.15 mg. The Codex Alimentarius Commission said that the new melamine content standard will help governments better protect consumer rights and health. ^[6]

Representative cases of melamine

Melamine milk powder incident

Main article: Dairy pollution incident in China

In 2008, many infants who consumed milk powder produced by Sanlu Group were found to have kidney stones, and subsequently found the chemical raw material melamine in their milk powder. According to the published figures, as of September 21, 2008, a total of 39,965 infants and young children who have received outpatient treatment consultations due to the use of infant milk powder, and 12,892 are currently in hospital. As of September 25, five people in Hong Kong and one in Macau were diagnosed with the disease. The incident aroused great concern from various countries and concerns about the safety of dairy products.

On January 22, 2009, the Shijiazhuang Intermediate People's Court of Hebei Province pronounced the first trial. Tian Wenhua, the former chairman of Sanlu, was sentenced to life imprisonment, while the senior executives of Sanlu Group Wang Yuliang, Hang Zhiqi, and Wu Jusheng were sentenced to 15 and 8 years respectively. And 5 years. As a unit defendant, Sanlu Group was convicted of producing and selling fake and shoddy products and was fined more than RMB 49.37 million. Dairy farmers Zhang Yujun, Gao Junjie and Geng Jinping who were suspected of manufacturing and selling melamine were sentenced to death, Xue Jianzhong was sentenced to life imprisonment, Zhang Yanjun was sentenced to 15 years in prison, Geng Jinzhu was sentenced to 8 years in prison, and Xiao Yu was sentenced to 5 years in prison.

Investigate Broad Food

On July 30, 2014, the Guangdong Public Security Department held a press conference. He Guangping, deputy director of the Guangdong Provincial Public Security Department, said that the department recently deployed the Chaozhou police to investigate and deal with the case of Chaozhou Boda Food Co., Ltd. suspected of producing and selling food that does not meet food safety standards, and successfully arrested the production and sale of yogurt tablets containing "melamine". Yang Mowu, the operator, seized 12.05 tons of finished yogurt flakes and 13.5 tons of semi-finished yogurt flakes produced by the company. After an in-depth investigation, the case was a major and complicated case involving many places in other provinces. The Guangdong Public Security Department promptly reported to the Ministry of Public Security to launch a national cluster campaign and organized 12 provinces and municipalities across the country to completely destroy the entire criminal network. ^[7]

On August 1, 2014, the Guangdong Food and Drug Administration held a press conference on the 1st. The Bureau and the Guangdong Police successfully detected the case of Chaozhou Boda Food Co., Ltd. suspected of producing and selling yogurt tablets containing "melamine" and seized the finished product. 12.05 tons of yogurt flakes and 13.5 tons of semi-finished yogurt flakes. Up to now, the police have detained five suspects involved in the case and arrested them. The case is still under investigation. ^[8]