Catalogue of molecular stereo models
Physical and chemical characteristics
Toxic hazards, diagnosis and treatment
Tolerance standard of human body to melamine
Pseudoprotein principle
Effect of adding melamine to milk
synthetic technique
Related pathogenic cases
How do families detect whether dairy products contain melamine?
Professional chemical detection methods for detecting melamine.
Professional chemical detection methods for detecting melamine.
Melamine is a triazine nitrogen-containing heterocyclic organic compound and an important nitrogen-containing heterocyclic organic chemical raw material. Triamine for short, also called 2,4,6-triamino-1, 3,5-triazine, 1, 3,5-triazine-2,4,6-triamine, 2,4,6-triaminourea, melamine, melamine, melamine.
More English names: 1, 3,5-triazine-2,4,6-triamine; 2,4,6-triamino-1, 3,5-triazine; 2,4,6-triamino -s- triazine; Aero melamine; Cyanuric acid triamide; Melamine; Melamine; DG 002 (amine); Hicophor PR Isoamine; Melamine; NCI-c 507 15； Pluragardpluragard C 133； 2,4,6-triamino-triazine; Teohan; Theoharnvirset 656-4；
CASNo.108781504654345677574316837955703719694977-27-2.
Edit the physical and chemical properties of this paragraph.
Melamine is pure white monoclinic crystal, tasteless, and its density is 1.573g/cm3 (16℃). Normal pressure melting point 354℃ (decomposition); Rapid heating sublimation, sublimation temperature is 300℃. Soluble in hot water, slightly soluble in cold water, slightly soluble in hot ethanol, insoluble in ether, benzene and carbon tetrachloride, soluble in methanol, formaldehyde, acetic acid, hot ethylene glycol, glycerol, pyridine, etc. Low toxicity. It is generally stable, but it may release cyanide at high temperature.
It is weakly alkaline (pKb=8) and can form melamine salt with hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid. Under neutral or weak alkaline conditions, all kinds of hydroxymethyl melamine are condensed with formaldehyde, but under weak acidic conditions (pH 5.5 ~ 6.5), they are condensed with hydroxymethyl derivatives to produce resin products. When hydrolyzed with strong acid or strong alkali aqueous solution, amino groups are gradually replaced by hydroxyl groups and become cyanuric acid diamide, which is further hydrolyzed to form cyanuric acid monoamide, and finally cyanuric acid is generated.
The main use of structural melamine Melamine is a basic organic chemical intermediate product with a wide range of uses, mainly used as a raw material for producing melamine formaldehyde resin (MF). Melamine can also be used as flame retardant, water reducer and formaldehyde cleaner. The hardness of this resin is higher than that of urea-formaldehyde resin, and it is nonflammable, water-resistant, heat-resistant, aging-resistant, arc-resistant and chemical-resistant. It has good insulation performance, luster and mechanical strength, and is widely used in wood, plastics, coatings, paper-making, textile, leather, electric power, medicine and other industries. Its main uses are as follows:
(1) Decorative board: it can be made into fire-proof, earthquake-resistant and heat-resistant laminated board, bright-colored, high-strength and heat-resistant decorative board, used as veneer for airplanes, ships and furniture, as well as fire-proof, earthquake-resistant and heat-resistant building decorative materials.
(2) Coatings: After etherification with butanol and methanol, it can be used as the base material of advanced thermosetting coatings and solid powder coatings, and can be used to make metal coatings and advanced amino resin decorative paints for automobiles and electrical appliances.
(3) Molding powder: Melamine plastic can be made by mixing, granulating and other processes, which is not excessive, resistant to contamination, and can still maintain good electrical properties when wet, and can be made into white, fall-proof household utensils, sanitary ware, porcelain-like tableware, electrical equipment and other advanced insulating materials.
(4) Paper: It can be used as a paper treatment agent after etherification with ether to produce high-grade paper such as anti-wrinkle, shrink-proof and non-perishable banknotes and military maps.
(5) Melamine formaldehyde resin can be mixed with other raw materials to produce fabric finishing agent, leather tanning agent, polishing agent and waterproof agent, rubber adhesive, combustion improver, high-efficiency cement water reducer, steel desalter, etc.
Edit this paragraph for toxic hazards, diagnosis and treatment.
At present, melamine is considered to be slightly toxic, and the lethal dose to rats is above 3 g/kg body weight. According to an experimental report of 1945, rats, rabbits and dogs were fed with large doses of melamine, and no obvious poisoning phenomenon was found. Long-term intake of melamine in animals will cause damage to reproductive and urinary systems, bladder and kidney calculi, and further induce bladder cancer. 1994 Volume III of the International Handbook of Chemical Safety and the International Chemical Safety Card jointly edited by the International Chemical Safety Agency and the European Commission only show that long-term or repeated intake of melamine may affect the kidneys and bladder, leading to stones. However, the preliminary investigation of pet food pollution in the United States in 2007 showed that wheat protein powder mixed with melamine ≤6.6% was the cause of pet food poisoning, which put a question mark on the above conclusion of slight toxicity. However, for safety reasons, melamine tableware will be marked "Do not use in the microwave oven".
On September 12, 2008, China's Ministry of Health issued the "Diagnosis and Treatment Plan for Urinary Calculi of Infants Related to Eating Contaminated Sanlu Infant Formula Milk Powder", which can be used as a reference for relevant parties.
It is pointed out in the plan that most stones involve bilateral collecting system and bilateral ureters, which is different from the clinical manifestations of adult urinary calculi, and the probability of multiple stones affecting renal function is high. Because most children do not have the ability to complain about symptoms, parents need to strengthen the observation of related children, and relying on abdominal B-ultrasound and/or CT examination is helpful for early diagnosis. In terms of treatment, there is no specific antidote for the toxic effect of melamine at present, and clinical treatment mainly depends on symptomatic support. If necessary, surgical intervention can be considered to reduce the risk of long-term damage to children's renal function. Early diagnosis and treatment is the key to a child's early recovery.
Edit the human tolerance standard for melamine in this paragraph.
Melamine is a low toxic chemical raw material. The results of animal experiments show that it is metabolized quickly in animals and will not remain, which mainly affects the urinary system.
There is an obvious dose-effect relationship between the dose of melamine and clinical diseases. The maximum tolerance of infants to melamine is per kilogram of milk powder 15 mg. Experts' risk assessment of contaminated infant formula shows that, taking an infant weighing 7 kg as an example, assuming daily intake of 150 g of milk powder, its safety preset value is 15 mg/kg of milk powder.
According to the standards of the US Food and Drug Administration, the daily tolerable intake of melamine is 0.63 mg/kg body weight per day.
Edit this pseudoprotein principle.
Melamine is often used as a food additive by unscrupulous businessmen to improve the protein content index in food testing due to the defects in the detection methods of protein content in food and feed industries, so melamine is also called "protein essence".
Protein is mainly composed of amino acids, and its nitrogen content generally does not exceed 30%, while the molecular formula of melamine contains about 66% nitrogen. The common protein test method "Kjeldahl method" estimates the content of protein by measuring the content of nitrogen. Therefore, adding melamine will make the protein content of food high, so that inferior food can pass the inspection of food inspection agencies. It is estimated that the content of test protein in plant protein powder and feed will increase by one percentage point, and the cost of using melamine is only 1/5 of that of real protein raw materials. Melamine, as a white crystalline powder, has no smell and taste, and it is not easy to be found after doping.
Milk powder incident: the protein content in all brands of milk powder is 15-20% (marked as 10-20% on supermarket packaging at night), and the average nitrogen content in protein is 16%. If the protein content of a qualified milk is 2.8% and the nitrogen content is 0.44%, the protein content of a qualified milk powder is 18% and the nitrogen content is 2.88%. The nitrogen content of melamine is 66.6%, which is 15 1 times that of milk and 23 times that of milk powder. Adding 0. 1g melamine to every 100g milk can increase protein by 0.4%.
Slightly soluble means that the solute 1g(ml) can be dissolved in the solvent 100 ~ less than 1000ml, and melamine is slightly soluble in water. The solubility in oil-in-water emulsion of milk has not been found in experimental data, so it should be better than that in water, which needs to be verified.
Detection scheme
In the existing national standards for milk powder detection, protein, fat and bacteria are mainly detected. Melamine is a chemical raw material, which is not allowed to be added to food, so the existing standards will not have corresponding content. In other words, there is no national standard for melamine testing at present. So, Germany Rhine t? In group V, melamine in baby food, pet food, feed and its raw materials (including starch, rice protein, corn protein, gluten, grain and oil, etc.) can also be detected by HPLC-UV with reference to the quantitative method of melamine in FCC. ), and the test results are authoritative.
In this paragraph, edit the function of adding melamine to milk
Milk powder is toxic because it contains melamine, which may be added directly to milk powder or to raw milk.
Melamine is added to milk and milk powder mainly because it can pass off as protein.
All foods should be tested for protein content according to regulations. If protein is not enough, it means that milk is mixed with too much water, which means that there is too much powder in other things in milk powder.
But protein is too difficult to detect, so biochemists have come up with a lazy way: because protein contains nitrogen, as long as the nitrogen content in food is measured, the content of protein can be calculated.
Therefore, it is difficult to detect unqualified protein, that is, melamine fake protein, in the milk powder added with melamine.
Edit this composition process.
Melamine was first synthesized by Justus von Liebig in 1834. In the early stage, dicyandiamide method was adopted: calcium carbide (CaC2) was hydrolyzed and dimerized to produce dicyandiamide, and then heated and decomposed to produce melamine, so as to prepare calcium cyanamide (CaCN2). At present, due to the high cost of calcium carbide, dicyandiamide method has been eliminated. Compared with this method, urea method has low cost and is widely used at present. Urea is boiled at 380-400℃ with ammonia as the carrier and silica gel as the catalyst, which is decomposed to produce cyanic acid and then condensed to produce melamine.
6 (NH2)2CO → C3H6N6 + 6 NH3 + 3 CO2
Cooling and trapping the generated melamine gas to obtain a crude product, then dissolving, removing impurities and recrystallizing to obtain a finished product. The production of melamine by urea method consumes about 3800 kilograms of urea and 500 kilograms of liquid ammonia per ton of product.
According to different reaction conditions, the synthesis process of melamine can be divided into high-pressure method (7- 10MPa, 370-450℃, liquid phase), low-pressure method (0.5- 1MPa, 380-440℃, liquid phase) and atmospheric method (
Most foreign melamine production processes are named after technology development companies, such as BASF process in Germany, Linz process in Austria, Lurgi process, United signal chemistry in the United States, Nissan process in Japan, DSM process in the Netherlands and so on. According to the different synthesis pressure, these production processes can be basically divided into three processes: high pressure process, low pressure process and atmospheric pressure process. At present, Japanese Nissan process, Italian Allied-Eurotechnica high-pressure process, Dutch DSM low-pressure process and German BASF atmospheric process are advanced and competitive processes in the world.
Melamine production enterprises in China mostly adopt semi-dry atmospheric pressure process. Under 0. 1MPa, urea is used as raw material and silica gel is used as catalyst to synthesize melamine at about 390℃. The melamine is crystallized in the condenser, and the crude product is dissolved, filtered and crystallized into the finished product.
Edit the relevant pathogenic cases in this paragraph.
In 2007, pet food in the United States was contaminated. According to the investigation, adding melamine ≤6.6% wheat protein powder is the cause of pet food poisoning.
In September, 2008, Sanlu infant milk powder was contaminated in China, causing infants who ate the contaminated milk powder to suffer from kidney calculi. The reason is also that milk powder contains melamine.
The General Administration of Quality Supervision, Inspection and Quarantine recently carried out a special inspection of melamine content in infant milk powder in China. This special inspection investigated the remaining 109 enterprises, and * * * inspected 49 1 batch products of these enterprises. The results of regular inspection showed that melamine was detected in 69 batches of products from 22 infant milk powder manufacturers.
List of enterprises that detected melamine in infant formula milk powder
Serial number Nominal enterprise product name Sampling number Unqualified number Maximum melamine content mg/kg
1 Sanlu infant formula milk powder of Shijiazhuang Sanlu Group Co., Ltd.1112563.00
2 Shanghai Panda Dairy Co., Ltd. Panda Kebao infant formula milk powder 5 3 6 19.00
3 Qingdao Shengyuan Dairy Co., Ltd. Shengyuan brand infant formula milk powder 17 8 150.00
4 Gucheng brand infant formula milk powder of Shanxi Gucheng Dairy Group Co., Ltd. 13 4 14 1.60
5 Jiangxi Guangming Hero Dairy Co., Ltd. Hero brand infant formula milk powder 2 2 98.60
6 Baoji Huimin Dairy (Group) Co., Ltd. Huimin brand infant formula milk powder 1 1 79. 17
7 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Mengniu brand infant formula milk powder 28 4 68.20
8 Sino-Australian joint venture Duojiaduo Dairy (Tianjin) Co., Ltd. Keqi brand infant formula milk powder 1 1 67.94
9 Guangdong Yashili Group Co., Ltd. Yashili brand infant formula milk powder 30 10 53.40
10 Nanshan Yi Bei infant formula milk powder of Hunan Pei Yi Dairy Co., Ltd. 3 1 32.00
1 1 Qining Dairy Co., Ltd. 2-stage base powder of infant formula milk powder 1 1 3 1.74
12 yashili brand infant formula milk powder of Shanxi yashili dairy co., ltd.4226.30
13 jinbi brand infant formula milk powder of Shenzhen jinbi dairy co., ltd.2218.00
14 Shien (Guangzhou) Infant Nutrition Co., Ltd. Shien brand infant formula milk powder 20 4 17.00
15 Jinding brand infant formula milk powder of Guangzhou Jinding Dairy Factory 3 1 16.20
16 inner Mongolia Yili industrial group co., ltd Yili brand children's formula milk powder 35 1 12.00
17 Yantai Ogilvy Nutrition Co., Ltd. Ogilvy brand infant formula milk powder 6 6 10.70
18 Qingdao suokang nutrition technology co., ltd. Aikeding brand infant formula milk powder 3 1 4.80
19 Xi Yubao infant formula milk powder of yanliang district Baiyue Dairy Co., Ltd. 3 1 3.73
20 Yantai Lei Lei Dairy Co., Ltd. Lei Lei brand infant formula milk powder 3 3 1.20
2 1 Shanghai Baoanli Dairy Co., Ltd. Baoanli brand infant formula milk powder 1 1 0.2 1
22 fuding city Chenguan Dairy Co., Ltd. Congerzhuang brand infant formula milk powder 1 1 0.09
List of batches of melamine detected in liquid milk
Company serial number Product name specification model trademark production date/batch of melamine (mg/kg)
Mengniu 1 Mengniu (Wuhan) Friends of Friends Dairy Co., Ltd. Walnut milk 200ml/ Bag Friends of Friends 200809 10 0.765
Mengniu 2 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Mengniu high-calcium low-fat milk 250ml/ case Mengniu 2008.08.07.0.8
Mengniu 3 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Full-fat sterilized pure milk 250ml/ case Mengniu 2008.09.0 1. 1.0
Mengniu 4 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. High calcium and low fat milk 250ml/ case Mengniu 2008.08.0 1. 1.5
Mengniu 5 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Breakfast Milk (Maixiang Type) 250ml/ bag Mengniu 200808 14 1.9
Mengniu 6 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Mengniu breakfast milk 250ml/ box Mengniu 2008.07.26/x 2.57
Mengniu 7 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. Miaodian 250ml/ carton Mengniu 20080728/W2063 438+07
Mengniu 8 Mengniu Dairy (Beijing) Co., Ltd. Xylitol Yogurt 2kg/ bottle Mengniu 20080806 3.52
Mengniu 9 Inner Mongolia Mengniu Dairy (Group) Co., Ltd. High calcium and low fat milk 243ml(250g)/ Bag Mengniu 20080908/C206/GAfb 4.2
Mengniu 10 Mengniu dairy (Maanshan) co., ltd. Mengniu daguo yogurt 160g/ case Mengniu M200809036.8 (sample a)
Mengniu 1 1 Mengniu Dairy (Maanshan) Co., Ltd. Mengniu Daguo Yogurt 160g/ case Mengniu M200809037 (sample B)
Yili 1 Jinan Yili Dairy Co., Ltd. Yili Mango+Yellow Peach Yogurt 125g/ carton Yili 2008.09.07.0.69
Yili 2 Inner Mongolia Yili Industrial Group Co., Ltd. Yogurt (papaya+sweet orange) 125g/ bottle Yili 20080903 1.02
3 Yili Inner Mongolia Yili Industrial Group Co., Ltd. Pure milk 220ml/ bag Yili 2008.09. 13.2
Yili 4 Inner Mongolia Yili Industrial Group Co., Ltd. skim milk 250ml/ box Yili 20080820 2.9
Yili 5 Inner Mongolia Yili Industrial Group Co., Ltd. Pure milk 220ml/ bag Yili 20080905MIAC6 5.5
Yili 6 Inner Mongolia Yili Industrial Group Co., Ltd. Pure milk 242ml/ bag Yili 20080906/LIA09 8
Yili 7 Inner Mongolia Yili Industrial Group Co., Ltd. High calcium and low fat milk 250ml/ box Yili 200808 19 8.4
Guangming 1 Beijing Guangming Jianneng Dairy Co., Ltd. Guangming Yogurt (original flavor) 180g/ BagGuangming 2008.09. 12 0.6
Guangming 2 Wuhan Guangming Dairy Co., Ltd. Original Yogurt 180g/ Box Guangming 2008-09- 13.45438+0
Guangming 3 Beijing Guangming Jianneng Dairy Co., Ltd. Original Yogurt 100g/ Cup Guangming 200809 10A 3.5
Guangming 4 Beijing Guangming Jianneng Dairy Co., Ltd. Big Fruit Strawberry Yogurt 450g/ box Guangming 20080902BC 4.8
Guangming 5 Bright Dairy Co., Ltd. Probiotics Excellent Cheese (Original Flavor) 190g/ jar Guangming B20080908C 5.65
Guangming 6 Beijing Guangming Jianneng Dairy Co., Ltd. Yogurt Yogurt (original flavor) 580 g/bottle Guangming B20080909A 8.6
Cases of illegally adding melamine
In 2007, Shenzhen Inspection and Quarantine Bureau detected melamine in three batches of "Aidou" ornamental fish feed imported from Taiwan Province Province, with high melamine content of 0.35 g/kg, 0.47g/kg and 0.5 1g/kg respectively. These three batches of fish feed are * * * 846kg, with the value of 10 16.
In 2007, Fujian, Tianjin, Shandong and Zhuhai Inspection and Quarantine Bureaus detected melamine positive from fish meal imported from Malaysia, Thailand and Peru (HS codes are all 230 120 1000), and the imported fish meal has been returned according to law.
According to the official news of the US Food and Drug Administration (FDA), the FDA found melamine in feed produced in the United States for the first time, and related companies have begun to recall related products automatically. The feed additives containing melamine are from Tembec BTLSR Company in Toledo, Ohio and Uniscope Company in Johnston, Colorado. Tembec produces AquaBond and Aqua-Tec II adhesives, which are mainly used for export, and supplies raw materials for producing Xtra-Bond adhesives to Uniscope, which mainly supplies the American market. The adhesive is mainly used to produce granular feed for cattle, sheep, goats, fish and shrimp. Tembec confirmed that melamine was added to the product formula to increase the viscosity of pellet feed. However, in the United States, melamine is prohibited as an animal or fish/shrimp feed additive.
In 2007, Beijing Inspection and Quarantine Bureau detected melamine positive in pet food imported from Australia (HS code is 2309 10 1000) and returned the imported pet food according to law.
How do Duan families detect whether dairy products contain melamine?
(1) Detect whether liquid milk contains melamine.
Melamine is slightly soluble in water, and its solubility in water is only 0.33% at room temperature, which means that only 0.33 g of melamine can be added to 100 g milk. The content of protein in 100g milk is about 3g, which means that after melamine is added to 100g milk, only 10g water can be added if water is added. For counterfeiting, the profit is too small and the risk is high. In addition, the most important thing is that the aqueous solution of melamine is alkaline. If melamine is added to milk, its PH value will be close to 8, which can be easily measured by an acid meter.
It is much easier to add melamine in the process of milk powder manufacturing. This is because the solubility of melamine increases rapidly with the increase of temperature. At 100℃, the solubility of melamine in water reached 5. 14%. In the process of milk powder manufacturing, the temperature of sterilization and spray granulation is about 65438 000℃.
There is a simpler way to prove who added melamine, that is, to measure the melamine content in different batches of milk powder with different production dates. If the melamine content of different batches and different production dates is not much different, it can be proved that melamine was added in the process of milk powder production, because if it was added by dairy farmers, so many dairy farmers, some added more, some added less, and those with conscience may not have added it. Then the melamine content in different batches of milk powder fluctuates greatly, and if it is added in the process of milk powder production, the melamine content in different batches of milk powder fluctuates little because of standard technology and automation equipment.
Teach you to detect whether milk powder contains melamine (detailed steps)
Because the safety of milk powder affects children's health, it is a top priority for parents. Thought of a simple method for everyone, for reference only.
(2) detecting whether the milk powder contains melamine;
1。 Wash the milk powder with hot water according to the weight thicker than usual, fully stir until there is no solid block, and then put it in the refrigerator to let the milk stand and cool.
2。 Prepare a black cloth and an empty cup. Cover the empty cup with a black cloth as a filter.
3。 Pour the cooled milk on a black cloth and filter.
4。 If the white solid is filtered out, rinse it with clear water several times to remove other soluble substances.
5。 If white crystals are found after washing, you can put the crystals in clean water. If the crystal sinks to the bottom of the water. That's probably melamine. This milk powder can't be used
This method may not be able to detect trace amounts of melamine, but trace amounts of melamine make children less likely to get stones, so at least it can be found out.
The above methods are for reference only.
Edit this professional chemical detection method to detect melamine.
Determination of melamine in animal food by gas chromatography-mass spectrometry
On-line detection of melamine content by spectral quadrupole
Determination of residual melamine in feed by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry
Determination of melamine in feed by RP-HPLC
Determination of melamine in high protein food by high performance liquid chromatography-diode array method
Determination of melamine in feed by high performance liquid chromatography
Determination of melamine in feed by HPLC-quadrupole mass spectrometry
Determination of melamine in pet food by solid phase extraction-high performance liquid chromatography
Analysis of melamine in pet food by liquid chromatography -MSMS
Determination of melamine residues in feed by liquid chromatography-tandem mass spectrometry
Determination of melamine in animal food by gas chromatography-mass spectrometry
2. 1 instruments and conditions
Agilent 1 100 High Performance Liquid Chromatograph (Agilent USA); Diode array detector with detection wavelength of 240nm and column temperature of 40℃.
( 1)agelavenustiltmasb 18(4.6×250mm)； Buffer: 10mM citric acid, 10mM sodium heptane sulfonate; Mobile phase: buffer solution: acetonitrile = 85:15; Flow rate: 1.0 ml/min.
(2)