Monitoring melamine plastic tableware products according to new standards
Total migration, melamine migration, formaldehyde migration
1 background
The  State Food and Drug Administration General Administration of Food and  Drug Administration released GB48061-2016 "Food Safety National Standard  Food" on October 19, 2016
Contact material
53  national food safety standards such as General Safety Requirements for  Materials and Products have replaced the old hygiene standards for food  packaging materials. Utilize the new criterion GB4806.7-20162 and the test standard GB316048-2016,
GB3160415-2016,  GB3160448-2015 for the detection of melamine plastic tableware products  related projects, can be found early melamine plastic tableware  products quality and safety risks. The  product standards, partial project limit values and related method  standards for the implementation of melamine plastic tableware are as  follows.
1.1GB9690-2009 "Sanitary standard for melamine-formaldehyde molded products for food containers and packaging materials"
1  Project name: Evaporation residue (mg/dm2) water, 60 ° C, 2 h, method  standard number and name: GBT500960-2003 "Analytical method for hygienic  standard of polyethylene, polystyrene and polypropylene molded products  for food packaging". Limited value: ≤ 2. 2  Project name: formaldehyde monomer migration (mg/dm2), 4% acetic acid  (volume fraction), 60 ° C, 2 h, method standard number and name:  GBT50061-2003 "analytical method for hygienic standard of melamine  molded products for food packaging" . The limit value is ≤2.5. 3  Project name: melamine monomer migration (mg/dm2), 49 acetic acid  (volume fraction), 60 ° C, 2h method standard number and name:  GBT23296.15-2009 "food contact material polymer material
Determination of 2,4.6-triamino-1,3,5-triazine (melamine) in food simulants by high performance liquid chromatography. Limited value: ≤0.2[9]
1.2GB4806.7-2016  "Food Safety National Standard Food Contact Plastic Materials and  Products" 1 Project Name: Total migration (mglm2), method standard  number and name: GB316048-2016 "Food Safety National Standard Food  Contact Materials and Products Determination of migration amount, limited value: ≤10. 2  Project Name: Formaldehyde monomer migration (mg/kg), method standard  number and name: CB3160448-2016 "Food Safety National Standard Food  Contact Materials and Products Determination of Formaldehyde Migration"  Limited Value: ≤15. 3  Project name: melamine monomer migration (mgkg), method standard number  and name: GB31604.15-2016 "Food safety national standard food contact  materials and products 2,4.6-triamino-1,3,5-triazine ( Determination of migration of melamine), limited value: ≤ 2.5 (in which infant food contact product limit value: ≤ 1). It  can be seen from the above standards that the new and old standards for  the implementation of melamine plastic tableware products are as  follows: different project names, different project migration  conditions, different project limit values, and different test method  standards. The  production date of the product will be judged according to the new  standard after April 19, 2017, so the monitoring of the melamine  tableware product project is necessary according to the new standard.
need. The  melamine tableware product testing is not summarized on the production  date, and the results are compared and counted according to the  GB4806.7-2016 standard.
2 sample collection
A  total of 60 batches (including 5 batches of infants and young children)  were sampled in this test. The main products are melamine bowls,  plates, cups, saucers, chopsticks, spoons, etc., regardless of sampling  area and sampling method.
3 test
3.1 Determination of migration conditions
GB9690-2009  standard specifies the evaporation residue (water, 60 ° C, 2h),  melamine monomer migration (4% acetic acid, 60 ° C 2h), formaldehyde  monomer migration (4% acetic acid, 60 ° C, 2h) The  simulated liquid, experimental temperature and experimental time are  extracted, and the GB4806.7-2016 standard is not clearly defined. The  corresponding test simulation liquid, experimental temperature and  experimental time need to be selected according to the actual use of the  product. The  experimental conditions for the total migration were 100 °C, 1 h, the  migration of melamine monomer and the migration of formaldehyde monomer  were 100 °C, 0.5 h. Because the melamine tableware has bowls, plates,  spoons, etc., it may be in contact. To  a variety of food categories, according to GB31604.1-2006, the  experimental simulation solution should be 4% acetic acid, 50% ethanol,  oil, etc., but according to different experiments, 4% acetic acid  solution is different for melamine tableware products. The  extraction ability of the simulated liquid (such as alcohol, grease,  etc.) is the strongest, so the experimental simulation solution selects  4% acetic acid according to the provisions of GB31604.1-2016 5.1.2, and  repeats the extraction test for 3 times. The results of the migration test are based on the compliance determination. The  melamine tableware in daily life is a product that is used repeatedly,  so the melamine tableware product testing project requires three  repeated tests.
3.2 Instruments and reagents
Main  instruments: Agilent 1200 liquid chromatograph; ERT-01 evaporation  residue constant weight instrument; FD115 electric blast drying oven;  UV-2450 ultraviolet spectrophotometer; DK-S28 electric thermostatic  water bath; Mili-QPUS ultrapure water system; XS204 electronic balance; standard material: formaldehyde standard solution (10.2mg/mL), BW3450, China Institute of Metrology. Formulation  of formaldehyde standard working series concentration (mg) according to  GB3160448-2016 standard; melamine standard sample, CAS NO108-78-1, Dr.  Ehrenstorfer. The concentration of melamine standard working series (mg/L) is prepared according to the standard of GB31604.15-2015. Main  reagents: glacial acetic acid, acetylacetone, anhydrous ammonium  acetate, sodium hydroxide, acetonitrile, sodium diphosphonate, etc. Among them, acetonitrile is analytically pure for other reagents of chromatographic purity. The test water is ultrapure water.
3.3 Sample Processing
The migration test pretreatment method of the sample was carried out according to GB5000156-2016. Among  them, hollow products according to the general method of clause 10.2.1  of GB5009.156-2016; fork spoon chopsticks according to the full  immersion method of clause 10.3 of GB50091562016; flat products if a  single sample can be injected into the food simulant volume ≥ 200mL,  using GB5009156- The  general method of clause 10.2.1 in 2016, if a single sample can be  injected into a food simulant with a volume<200mL, the full  immersion method of clause 10.3 of GB5009.156-2016 is adopted; the rest  of the products are required according to the requirements of  GB5009.156-2016, according to the actual situation Process and convert.
3.4 Equipment conditions
3.4.1 Formaldehyde migration
Formaldehyde  reacts with acetylacetone in the presence of ammonium acetate to  produce yellow 3,5-diacetyl-1,4-di-light dimethyl acridine, and the  absorbance of the industry is measured by spectrophotometer at 410 mm,  compared with the standard series. The  content of formaldehyde in the food simulant is obtained, and the  migration amount of formaldehyde in the sample is obtained.
3.4.2 melamine migration 4% acetic acid extract through the membrane direct injection test. Chromatographic  conditions: column, amino column, column length 250mm, column inner  diameter 46mm, particle size 5μm; mobile phase, acetonitrile-phosphate  buffer solution (75+25); flow rate
, 0.8 mL / min; detection wavelength, 230 mm.
3.5 detection
3.5.1 Formaldehyde migration
Pipette  50mL of the simulated sample solution and blank solution into a 10ml  colorimetric tube, add 50mL of acetylacetone solution, cover the plug  and mix well. The colorimetric tube was placed in a 40 ° C water bath for 30 min, taken out and then cooled at room temperature. Take  another 10mL colorimetric tube and add 0, 0.5, 1.0, 1.5, 2.0, 2.5, 30mL  of formaldehyde standard working series concentration 0, 1.0, 20, 3.0,  4.0, 50, 6.0mg, supplemented with 4% acetic acid solution. To 5:0 mL, 50 mL of acetylacetone solution was added and treated with the sample treatment method. The  colorimetric value of the standard solution, the sample solution and  the blank solution (reference liquid) after the color development is  measured at 410 m, and the concentration of formaldehyde in the sample  solution (mg/L) is calculated from the standard curve.
3.5.2 Test method for determination of melamine by high performance liquid chromatography
The mock sample and the blank were directly filtered through a 0.22 μm filter and tested.
4 results and analysis
4.1 Results
The total migration (4% acetic acid, 100 ° C, 1 h) test results, taking 10 samples as an example, see Table 1.

It  can be seen from Tables 1, 2 and 3 that the total migration of melamine  tableware products (4% acetic acid, 100 ° C, 1 h), melamine migration  (4% acetic acid, 100 ° C, 0.5 h), formaldehyde migration (4%) Acetic  acid, 100 ° C, 0.5 h) monitoring project, the corresponding value  increased with the increase of the number of extractions.
4.2 Analysis
In  this monitoring, a total of 60 batches were sampled, and there were 20  batches of problem samples (ie exceeding the standard requirements), and  the failure rate was 333%. The  total migration (4% acetic acid, 100 ° C, 1 h) failed batches of 6  batches, melamine migration (4% acetic acid, 100 ° C, 0.5 h) unqualified  batches of 15 batches (including 3 batches) Infant  and child products, 5 batches of infant and toddler products),  formaldehyde migration (4% acetic acid, 100 ° C, 0.5 h) unqualified  batches are 0 batches. During  the testing process, it was found that some samples showed a lot of  visible flocculation during the extraction process, and such total  sample migration index would easily exceed the standard requirements. The  entry of these residues into the human body will have adverse effects  on health, and the residue will directly affect the color, aroma and  taste of the food. The  melamine item has the largest number of samples, including 5 batches of  infant and child products, but 3 batches exceed the standard 1mg/kg  requirements.
Melamine  is a chemical that is banned from being used in food and animal feed.  It is inherently less toxic, but if it is ingested by the human body,  melamine is hydrolyzed by a strong acid or a strong aqueous alkali  solution, and the amine group is gradually replaced by a hydroxyl group  through an intermolecular hydrogen bond. Combined  with the formation of reticulated melamine cyanurate (MCA), the crystal  is hardly soluble in water, easily accumulates in the kidney to form  stones, block the renal tubules, and eventually lead to kidney failure. Most  adults generally excrete most of the melamine, but because children's  kidney development is not mature, melamine is more harmful to children. The  above reasons may be that the product standard has just been changed,  and the production company has not strictly controlled the production  process according to the new standard. This monitoring of the melamine  tableware product is helpful for early detection and solving problems,  thereby reducing the melamine tableware product. The unqualified rate makes the people more comfortable to use melamine tableware products.
references:
[National  Health and Family Planning Commission GB4806.1-2016 National Food  Safety Standards General Requirements for Food Contact Materials and  Products [S] Beijing: China Standard Press, 2016
[2]  National Health and Family Planning Commission. GB48067-2016 National  Food Safety Standards for Food Contact Plastic Materials and Products  [S], Beijing China Standard Press, 2016
[3]  National Health and Family Planning Commission. GB316048-2016 National  Food Safety Standard Determination of Total Migration of Food Contact  Materials and Products [S] Beijing: China Standard Press, 2016
[4]  National Health and Family Planning Commission. GB3160415-2016 National  Food Safety Standards Food Contact Materials and Products  2.4.6-Triamino-1,3,5-triazine (melamine) migration determination [S]  Beijing China Standard Publisher, 2016
[5]  National Health and Family Planning Commission. GB3160448-2016 National  Food Safety Standard Determination of Formaldehyde Migration in Food  Contact Materials and Products [S] Beijing: China Standard Press, 2016
[6]  China National Standardization Administration Committee.  GB/T500960-2003 Analytical method for sanitary standards for  polyethylene, polystyrene and polypropylene molded products for food  packaging [S] Beijing: China Standard Press, 2003
[7]  China National Standardization Administration Committee.  GB/T500961-2003 Analytical method for sanitary standards for melamine  molded products for food packaging [S] Beijing: China Standard Press,  2003
[8]  National Health and Family Planning Commission. GBT232096.15-2009 Food  Contact Materials Polymer Materials Food Simulators Determination of  2,4.6-triamino-1,3,5-triazine (melamine) by high performance liquid  chromatography [S] Beijing: China Standard Press, 2009
[9]  China National Standardization Administration Committee. GB9690-2009  Sanitary standard for melamine-formaldehyde molded products for food  containers and packaging materials [S] Beijing: China Standard Press,  2009
[10]  National Health and Family Planning Commission Office GB500.156-2016  National Food Safety Standards Food Contact Materials and Products  Migration Test Pretreatment Methods General [S] Beijing: China Standard  Press, 2016 Chen Shi, Jing Wei, Lu Shuiyuan, etc. .  Analysis of migration of melamine and its derivatives in food contact  products by liquid chromatography in universities, 2011, 39(10):  1572-1576