GB/T 5009.81-2003 Analytical methods for hygienic standards of stainless steel tableware containers

This standard specifies the analytical method for the hygienic standard of stainless steel tableware containers. This standard is applicable to the determination of various hygienic indicators of various cookers, tableware, tableware and other food contact containers, tools, equipment, etc. made of stainless steel. GB/T 5009.81-2003 Analytical method for the hygienic standard of stainless steel tableware containers GB/T5009.81-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.81—2003
Replaces GB/T11681—1989
Method for analysis of hygienic standard of stainless steel food containers and tablewaresPromulgated on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on January 1, 2004
GB/T5009.81--2003
This standard replaces GB/T11681--1989 "Method for analysis of hygienic standard of stainless steel food containers and tablewares". Compared with GB/T11681-1989, this standard has been modified as follows: The structure of the original standard has been modified according to GB/T20001.4-2001 "Standard Writing Rules Part 4: Chemical Analysis Methods".
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanxi Provincial Health and Epidemic Prevention Station and the Liaoning Provincial Food Hygiene Supervision and Inspection Institute. The main drafters of this standard are Li Wenyuan, Liu Guoxiang, Shi Chongyi, Lu Guihua, Xu Min, Li Min, and Zhang Hua. The original standard was first issued in 1989, and this is the first revision. 584
1 Scope
Analysis method for hygienic standards of stainless steel tableware containers This standard specifies the analysis method for hygienic standards of stainless steel tableware containers. GB/T5009.81—2003
This standard is applicable to the determination of various hygienic indicators of various cookers, tableware, tableware and other containers, tools, equipment and other food contact containers made of stainless steel.
2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties reaching an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated references, the latest versions are applicable to this standard. GB/T5009.12 Determination of lead in food
GB/T5009.62 Analytical method for hygienic standards of ceramic tableware containers GB/T5009.72 Analytical method for hygienic standards of aluminum tableware containers 3 Preparation of test samples
3.1 Sampling method
Take samples of 0.1% of the product quantity, and produce in small batches. Each sample should be no less than 6 pieces, and the product name, batch number, steel grade and sampling date should be marked respectively. Half of the sample is used for testing, and the other half is kept for two months for arbitration analysis. 3.2 Appearance inspection
The finished product has a straight shape, a smooth surface and no corrosion spots. 3.3 Soaking conditions
3.3.1 Reagents
4% (volume fraction) acetic acid: Measure 4mL of glacial acetic acid or 11mL of 36% (volume fraction) acetic acid and dilute it to 100mL with water. 3.3.2 Sample preparation
Wash the dirt on the surface of the sample with soapy water, rinse it with tap water, then rinse it with distilled water, and dry it for later use. For tableware containers with regular shapes that are easy to measure and calculate the surface area, take two finished products from each batch, calculate the soaking area and inject water to measure the container volume (preferably 2/3 to 4/5 of the volume). Note the area and volume, pour off the water, and drip dry. For products with irregular shapes, large volumes or difficult to measure and calculate surface areas, the raw materials (plates) or representative products of the same batch (products using the same steel grade as raw materials) can be used as samples to cut a certain area of ​​plates. The soaking area is calculated as the total area, and the total area of ​​the plates should not be less than 50cm. Take three samples from each batch and put them in beakers of appropriate volumes. The amount of soaking liquid added is calculated as 2mL per square centimeter. If both sides are in the soaking liquid, the total area should be multiplied by 2. Pour the boiling 4% acetic acid into the finished product container or the beaker containing the plate, add a glass cover, boil on low heat for 0.5h, remove it, add 4% acetic acid to the original volume, leave it at room temperature for 24h, and pour the above sample soaking liquid into a clean glass bottle for analysis.
The 4% acetic acid soaking liquid lost due to evaporation during the boiling process should be replenished at any time. The metal content in the 4% acetic acid soaking liquid in the container is also calculated as 2mL soaking liquid per square centimeter according to the calculation formula of the analysis results. 585
GB/T5009.81—2003
4 Determination of chromium, lead and nickel
4.1 Graphite furnace atomic absorption spectrophotometry
4.1.1 Principle
The sample is injected into a graphite tube, and current is passed through both ends of the graphite tube to increase the temperature. The sample is atomized after drying and ashing. The atomic vapor generated during atomization absorbs specific radiation energy, and the amount absorbed is proportional to the content of the metal element. The content of the sample is quantitatively compared with the standard series. 4.1.2 Reagents
4.1.2.150g/L diammonium phosphate solution: weigh 5g diammonium phosphate (NH,HPO, high-grade purity), dissolve it in water, and dilute to 100mL
Chromium standard solution: accurately weigh 4.1.2.2
2.8289g of potassium dichromate (KzCr2O, standard reagent) that has been dried at 105℃~110℃ to a constant amount, dissolve it in 50mL of water, transfer it to a 1000mL volumetric flask, add 2mL of nitric acid, shake the hook, and dilute to the scale with water. Each milliliter of this solution is equivalent to 1mg of chromium.
4.1.2.3 Lead standard solution: accurately weigh 1.0000g of metal lead (Pb, 99.99%), add 5mL c(HNO,) = 6mol/L nitric acid to dissolve, transfer to a 1000mL volumetric flask, add water to dilute to scale, this solution is equivalent to 1mg lead per milliliter. 4.1.2.4 Nickel standard solution: accurately weigh 1.0000g of metal nickel (Ni, 99.99%), add 5mL c(HNO) = 6mol/L nitric acid to dissolve, transfer to a 1000mL volumetric flask, add water to dilute to scale. This solution is equivalent to 1mg nickel per milliliter. 4.1.2.5 Chromium, nickel, lead standard working solution: before use, gradually dilute the chromium, nickel, lead standard solution into a metal standard working solution equivalent to 1g per milliliter.
4.1.3 Instrumentswww.bzxz.net
4.1.3.1 Graphite furnace atomic absorption spectrophotometer. 4.1.3.2 Pyrolytic graphite tube and high-purity argon gas. 4.1.3.3 Micro-dispenser.
4.1.4 Analysis steps
4.1.4.1 Preparation of sample and mixed standard series Pipette 0.50mL1.00mL of sample soaking solution into a 10mL volumetric flask; take another 6 10mL volumetric flasks and pipette metal standard working solution respectively, chromium: 0, 0.20, 0.40, 0.60, 0.80, 1.00mL; nickel: 0, 0.50, 1.00, 1.50, 2.00, 2.50mL lead: 0, 0.30, 0.60, 0.90, 1.20, 1.50mL. Add 1.0mL50g/L diammonium phosphate solution to the sample and standard tubes, dilute to the mark with water, and mix well. The prepared standard series metal contents are: chromium: 0.0.20, 0.40, 0.60, 0.80, 1.00ug: nickel: 0, 0.50, 1.00, 1.50, 2.00, 2.50μg lead: 0.0.30, 0.600.90, 1.20, 1.50μg. 4.1.4.2 Instrument working conditions
Chromium, nickel, and lead all use sensitive analysis lines (chromium 357.9nm; nickel 232.0nm: lead 283.3nm), slit width, nickel is 0.19nm, chromium, lead is 0.38nm, determination method is BGC, peak value recording, internal gas flow rate 1L/min injection volume 20μL, gas is stopped during atomization, and graphite furnace heating program is shown in Table 1.
Graphite furnace heating program
4.1.4.3 Determination
150/30
150/30
150/30
800/30
600/30
500/30
Atomization
2700/6
2600/6
1600/7
Use a micro-liquid dispenser to draw the reagent blank, standard series and sample solution into the graphite furnace atomizer for determination. Draw a calibration curve based on the peak recording results, and find the metal content (μg) of the sample from the calibration curve. 586
4.1.5 Calculation of results
See formula (1) and formula (2).
Where:
(mi-mz)x1000
VX1000
X—+The metal content in the sample immersion solution, in milligrams per liter (mg/L); mi
The metal mass in the sample determination tube obtained from the calibration curve, in micrograms (μg); The metal mass in the reagent blank tube, in micrograms (ug); The volume of the sample immersion solution taken during the determination, in milliliters (mL); The correction factor converted to 2mL immersion solution per square centimeter: V. The total volume of the sample immersion solution, in milliliters (mL); S--The sample area in contact with the immersion solution, in square centimeters (cm): 2mL immersion solution per square centimeter, in milliliters per square centimeter (mL/cm). 2
4.2 Diphenylcarbohydrazide colorimetric method (determination of chromium) 4.2.1 Principle
CB/T5009.81-2003
Use potassium permanganate to oxidize low-valent chromium to high-valent chromium (Cra+), add sodium hydroxide to precipitate iron, add sodium pyrophosphate to conceal the remaining iron, etc. Use diphenylcarbohydrazide to generate a red complex with chromium, and compare with the standard series for quantitative determination. 4.2.2 Reagents
4.2.2.1 Sulfuric acid: c (HzSO.) = 2.5 mol/L. Take 70 mL of high-grade pure sulfuric acid and add it to water while stirring. After cooling, add water to 500 mL
4.2.2.2 3g/L potassium permanganate solution: Weigh 0.3g of potassium permanganate and dissolve it in water to 100 mL. 4.2.2.3 200g/L urea solution: weigh 20g urea and dissolve in water to 100mL. 4.2.2.4 100g/L sodium nitrite solution: weigh 10g sodium nitrite and dissolve in water to 100mL. 4.2.2.5 Saturated sodium hydroxide solution.
4.2.2.6 50g/L sodium pyrophosphate solution: weigh 5g sodium pyrophosphate (Na,P,O,.10HzO), dissolve in water to 100mL. 4.2.2.7 Diphenylcarbazide solution: weigh 0.5 diphenylcarbazide and dissolve in 50mL acetone, add 50mL water, prepare before use, store in a brown bottle, if the solution becomes darker in color, it cannot be used. 4.2.2.8 Chromium standard solution: prepare in the same way as 4.1.2.2, the concentration of the solution is 10μg chromium per milliliter. 4.2.3 Instruments
4.2.3.1 Spectrophotometer, 3cm colorimetric cup. 4.2.3.2 25mL stoppered colorimetric tube.
4.2.4 Analysis steps
4.2.4.1 Drawing of standard curve
Pipette 0.0.25, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00mL of chromium standard solution and transfer them to 100mL beakers respectively. Add 4% (volume fraction) acetic acid to 50mL. The following operations are the same as those for the sample. Draw the standard curve with absorbance as the ordinate and standard concentration as the abscissa.
4.2.4.2 Determination
Put 50mL of sample soaking solution into a 100mL beaker, add 2 glass beads, 2mL of 2.5mol/L sulfuric acid (4.2.2.1), and a few drops of 3g/L potassium permanganate solution, mix, heat and boil until about 30mL (when the reddish color disappears, add 3g/L potassium permanganate solution to turn it reddish), let cool, add 25mL of 200g/L urea solution, mix, add 100g/L sodium nitrite solution dropwise until the reddish color disappears, add saturated sodium hydroxide solution to make it alkaline (pH=9), and place for 2 h later, filter, add water to the filtrate to 100mL, mix, take 20mL of this solution in a 25mL colorimetric tube, add 587
GB/T5009.81--2003
1mL2.5mol/L sulfuric acid (4.2.2.1), 1mL50g/L sodium pyrophosphate solution, mud, add 2mL5g/l. diphenylcarbazide solution, add water to 25mL, mix, let stand for 5min, measure the absorbance at 540nm, take another 100mL of 4% acetic acid solution and perform the same operation as above, as the reagent blank, adjust the zero point.
4.2.5 Calculation of results
See formula (3).
50×100
Wherein:
Chromium content in the sample immersion solution, in milligrams per liter (mg/L); m-the mass of chromium in the sample solution during determination, in micrograms (μg); F is the same as 4.1.5.
4.3 Diacetyl colorimetric method (determination of nickel)
4.3.1 Principle
Nickel forms a red complex with diacetyl under weak alkaline conditions, which is extracted with chloroform. The chloroform extract is back-extracted with dilute hydrochloric acid. Bromine water is added to the dilute hydrochloric acid extract, and then ammonia water is added for decolorization. It forms a red substance with alkaline diacetyl, which is quantitatively compared with the standard series. 4.3.2 Reagents
4.3.2.1 100g/L diammonium citrate solution: weigh 10g diammonium citrate [(NH), HC.H,O, and dissolve in water to 100mL. 4.3.2.2 10g/L diacetyl ethanol solution: weigh 1g diacetyl [(CH), C (NOH)] and dissolve in ethanol [95% (volume fraction) to 100mL. If there is insoluble matter, filter and keep the filtrate for later use. 4.3.2.3 10g/L alkaline diacetyl solution: weigh 1g diacetyl and dissolve in c (NaOH) = 0.2mol/L sodium hydroxide solution to 100mL.
4.3.2.4 Hydrochloric acid: c (HCI) = 0.5mol/L. 4.3.2.5 4% (volume fraction) acetic acid.
4.3.2.6 Ammonia water: c(NHOH)=5mol/L. Ammonia water: c(NHOH)=2mol/L.
4.3.2.8 Ammonia water: c(NH,OH)=0.3mol/L. 4.3.2.9 20% (volume fraction) sodium hydroxide solution. 4.3.2.10 Nickel standard solution: Preparation method is the same as 4.1.2.4, and the concentration of the solution used is 10μg nickel per milliliter. 4.3.3 Instruments
4.3.3.1 Spectrophotometer, 1cm colorimetric cup. 4.3.3.2 25mL stoppered colorimetric tube.
4.3.3.3 125mL, 60mL separatory funnel. 4.3.4 Analysis steps
4.3.4.1 Drawing of standard curve
Pipette 0, 0.25, 0.50, 1.00, 2.00, 3.00, 4.00, 5.00mL of nickel standard solution and add 4% acetic acid to 100mL, transfer to a 125mL separatory funnel, and operate the same as the sample below, with absorbance as the ordinate and standard concentration as the abscissa, to draw a standard curve. 4.3.4.2 Determination
Take 100mL of the sample soaking solution, add 20% sodium hydroxide solution to neutral or weak alkalinity, let stand for 2h, filter, transfer the filtrate to a 125mL separatory funnel, add 2mL of diammonium citrate solution, and add a few drops of 2mol/L nitrogen water (4.3.2.7) to adjust the solution pH to 8-9. Add 2 mL of diacetyl ethanol solution, add 10 mL of chloroform, shake vigorously for 1 min, let stand, and separate the chloroform into a 60 mL separatory funnel. Add 5 mL of chloroform to the water layer and repeat the above operation twice, combine the chloroform liquid, and discard the water layer. Wash the chloroform layer with 10 mL 0.3 mol/L ammonia water (4.3.2.8), shake vigorously for 30 s, let stand, separate the chloroform layer and put it in another 60 mL separatory funnel. Add 10 mL 0.5 mol/L hydrochloric acid (4.3.2.4) to the funnel, shake vigorously for 1 min, let stand, separate the fluoroform layer and put it in another separatory funnel, add 5 mL 0.5 mol/L hydrochloric acid (4.3.2.4) and perform the same operation as above. Combine the hydrochloric acid solutions, transfer them to a 25 mL stoppered colorimetric tube, add 2 mL saturated bromine water and shake. Let stand for 1 min, add 5 mol/L ammonia water (4.3.2.6) until it becomes colorless, then add 2 mL of 5 mol/L ammonia water (4.3.2.6), cool to room temperature in running water, add 2 mL of alkaline diacetyl solution, add water to 25 mL and mix thoroughly, let stand for 20 min, and measure the absorbance at 540 nm. Take another 100 mL of 4% acetic acid solution and perform the same operation as above as a reagent blank, and adjust the zero point. 4.3.5 Calculation of results
See formula (4).
Where:
X-Nickel content in the sample immersion solution, in milligrams per liter (mg/L); -The mass equivalent to nickel in the sample solution during the determination, in micrograms (g); m
-The volume of the sample solution during the determination, in milliliters (mL); F-Same as 4.1.5.
4.4 Dithiol trace method (determination of lead)
4.4.1 Principle
Same as Chapter 20 of GB/T5009.12-2003. 4.4.2 Reagents and instruments
Same as GB/T5009.12-2003, Chapter 21, Chapter 22. The lead standard solution is prepared according to GB/T5009.12-2003. 4.4.3 Analysis steps
Measure 10.0mL of the sample soaking solution. Add water to dilute accurately to 50mL. Take two 25mL stoppered colorimetric tubes, add 10.0mL of soaking diluent to one, add 2.0mL of lead standard solution (equivalent to 2μg) and 1mL of 4% acetic acid to the other, and then add water to 10mL. Add 1.0mL of ammonium citrate solution, 0.5mL of hydroxylamine hydrochloride solution and 1 drop of phenol red indicator solution to the two tubes respectively. After mixing, add ammonia water until it turns red and add 1 more drop, and then add 1.0mL of potassium cyanide solution. Shake the spoon. Add 5.0mL of disulfide-trichloromethane solution to each tube and shake for 2min. After standing, perform colorimetry. The red color of the sample tube should not be darker than that of the standard tube. Otherwise, use a 1cm colorimetric cup, adjust the zero point with chloroform, and measure the absorbance at a wavelength of 510nm for comparative quantification. 4.4.4 Result calculation
Same as 4.1.5.
5 Determination of cadmium
5.1 Principle, reagents, instruments, and preparation of standard curves are the same as Chapter 7 of GB/T5009.62-2003. 5.2 Determination
Pull 50mL of sample soaking solution into a beaker, heat and concentrate on a hot plate, and then transfer to a 10mL volumetric flask. Spray into the flame for determination, and compare with the standard curve for quantification.
5.3 Result calculation
Same as 4.1.5.
6 Determination of arsenic
Operate according to the provisions of GB/T5009.72-2003. Result calculation is the same as 4,1.5.
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