GB 8058-1987 Ceramic cooking utensils, lead, cadmium leaching limit and detection method GB8058-1987 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Ceramic Cooker
Staudard pernlssible limits and testing method for release oflead or cadmium from ceramic cook wareUDC643.35+666.3||tt| |#543.06
GB 8058-87
This standard is equivalent to the international standard ISO8391/1--86 Food Contact Ceramic Cooking Lead and Copper Dissolution Test Method Standard and ISO8391/2 8. For ceramic cookware drills that come into contact with food, the dissolution amount is allowed to be extremely high. This standard applies to ceramic cooking products such as casseroles, steam pots, "tea pots", hot pots and woks that come into contact with food. 1 Definition
Ceramic cookers refer to ceramic products for heating and preparing food: but do not include glass, glass ceramics and porcelain products: 2 Allowable limits
Using the methods specified in this standard, from any single Allowable limit for dissolution of lead and lead in products Pb≤5μg/mLtCd≤0.5μg/ml
3 Test methods
3.1 Principle
3.2 Reagents
Use hot acetic acid The solution extracts lead and. 3.2.1 Distilled water
Distilled water or ion exchange water is used throughout the analysis process. 3.2.2 Glacial acetic acid (CH:COOH) analytical grade) with a specific gravity of 1.05 is stored away from light. 3.2. Preparation of 34% acetic acid solution
Dilute 40 mL of glacial acetic acid with a specific gravity of 1.05 with distilled water to 100 mL. Prepare this solution before use. 3.2.41.00mg/mL lead backup solution is prepared by adding 1.8308g lead acetate [Pb(CH.COO):·3H.O (excellent grade pure) or 1.5985g lead nitrate (Pb(NO)2 (excellent grade pure)) Place it in a 400mlL beaker, dissolve it slowly with 40ml of glacial acetic acid with a specific gravity of 1.05, and then cool it. Transfer to a 1000mL volumetric flask, dilute to volume with steamer water, and shake well.
3.2.50.1 mg/mml. To prepare the lead reserve solution, use a burette or pipette to transfer 10 mL of the lead reserve solution with a concentration of 1.0 mg/mL, transfer it into a 100 mL volumetric flask, and dilute to the mark with 4% acetic acid solution. , shake well and set aside.
3.2.6 Lead Standard Solution
Use a burette or pipette to pipette 0.30.0.50.1.00.2.00.3.00.4.00.5.00, 6.00.7.0010.00m1. The expansion is 0.1mg/ ml of lead reserve solution were placed in 100 mL volumetric flasks, diluted to the mark with 4% acetic acid solution, and shaken. The solution contains lead 0.30.0.50.1.00 and 2.00.3.00.4.00.5.00.6.00.7.00.10.00 milliliters respectively. After four weeks of use, replace the bath solution with a new one. | |tt |
Place 1.1423g of oxidation pot (Cd0 (excellent grade pure)) in a 400mL beaker, dissolve it with 40mL of glacial acetic acid with a specific gravity of 1.05, and then cool. Move it into a 1000mL volumetric flask and dilute to the mark with distilled water. Shake the hook and set aside for later use. 3.2. To prepare the 80.01mg/mL cadmium backup solution, use a burette or pipette to transfer 10mlL of the backup solution with a concentration of 1.0mg/mL into a 1000mL volumetric flask, dilute it to the mark with 4% acetic acid bath solution, and place the hook on the hook. Reserve.
3.2.9 Standard solution
Use a burette or pipette to pipette 0.30, 0.50.1.00.2.00, 3.00, 4.00, 5.00.10.00.20.00mL to 0.01m/mL. The radium reserve solution was placed in a 100ml volumetric flask, diluted to the mark with 4% acetic acid solution, and shaken well. The drops contained 0.03.0.05, 0.10.0.20.0.30, 0.40, 0.50.1.00, and 2.00g per milliliter respectively. , the solution should be replaced with a new one after four weeks of use. 3.3 Receiver and equipment
3.3.1 Atomic absorption spectrophotometer: The lower detection limit of lead when the instrument sensitivity is 1% absorption rate is required to be 0.5 milliliters. /mL, the lower detection limit for pot is 0.05μg/mL.
3.3.2 Device III: Use similar device III such as borosilicate or polyoxyethylene. 3.4 Sample
3.4. 1. Sampling quantity: Six products of the same specifications are taken for each test. The size, shape, color and decoration of the sample should be marked. 3.4.2 Effective volume of the sample: Pour water to the edge of the regulator and open it. The amount of water is the effective volume of the sample. 3.4.3 Sample processing
First, wash the sample in a weak alkaline solution at about 40°C to remove grease or other substances that may affect the detection effect, and use tap water. Rinse, then rinse with distilled water or ion-exchange water, and dry. 3.5 Testing procedures
3.5.1 Liquid filling
Use evaporation. Pour water into two-thirds of the effective volume of the cooker, and then cover it with its own lid. Products without lids should be covered with flat, opaque, lead-free, glass-free lids to prevent melting and evaporation and avoid illuminating the surface of the sample during the test. 3.5.2 Extraction
Place the cooker on the heating plate, heat the water to slowly boil, and then add enough glacial acetic acid (3.2.2) to prepare a 4% (V/) acetic acid solution. . The volume Va of glacial acetic acid added can be calculated by the following formula: Va-0041V
where: w-water capacity in the cooker, mL. If the cooker itself has a heating device, use a heating device to bring it to temperature. Keep the solution boiling slowly (low boiling point) from the time of adding acetic acid, and continue to boil slowly for 2 hours. If the loss of the test solution occurs during the 2 hours of heating, replenish it with the pre-prepared 4% acetic acid solution (3.2.3) to make the cooking The solution in the container is maintained at two-thirds of the capacity for +2 hours and then the heat source is removed immediately. 3.5.3 Extraction of the extract
When extracting the extract, use a pipette to re-aspirate and release or use a silica glass rod to stir continuously to achieve the purpose of filling the solution evenly. Avoid extraction when mixing. loss of fluid and damage to the test surface. Transfer the mixed extraction solution to the container (3.3.2) for storage (it is not necessary to transfer all of it) and measure it as soon as possible to prevent lead and cadmium in the solution from being adsorbed by the wall of the container.
3.5. Instrument calibration
3.5.4.1 Adjust the instrument according to the instrument manual to make its sensitivity meet the requirements specified in 3.4.1. 3.5.4.2 Use the standard solutions of 3.2.6 and 3.2.9 to measure respectively on an atomic absorption spectrophotometer, record the absorbance of the corresponding concentration, and draw a standard curve.
3.6 Determination of lead and cadmium
Take the standard solutions of 3.2.6 and 3.2.9, and use the solution with the highest concentration to determine the lead and cadmium in the extraction solution in 3.6.1 extraction| |tt||115wwW.bzxz.Net
GB 8058—87
Approximate concentration comparison, if the lead content in the extraction solution is higher than 10pg/mL. or the cadmium content is higher than 2g/mL, part of the extraction solution should be extracted for use Dilute the 4% acetic acid solution until lead is less than 10ug/ml or cadmium is less than 2μg/mL. After roughly measuring the lead and cadmium content of the extraction solution, you can choose one of the following three methods for precise measurement. 3.6.2 Direct comparison method
According to the size of the initial measurement value, select lead and saw standard solutions (3.2.6 and 3.2.9) with similar concentrations, and measure the crude measurement solution on the atomic absorption spectrophotometer Spray, record the readings of the absolute absorption value A of more than three times for each solution, and calculate the average. The lead and cadmium concentrations of the extraction solution are expressed in μg/mL. The results are calculated using formula (1): AF
Ag| |tt||In the formula: c-
C
-Lead and cadmium content of the extraction solution.g/ml
-Lead of the standard solution, content, ag/mL! A.—The absolute absorption value measured by the standard solution A-The absolute absorption value measured by the extraction solution:
F—Dilution factor of the solution.
3.6.3 Close interpolation method
The two standard solutions and the crude test solution are measured at the same time. Record the readings of the absolute absorption value A of more than three times for each solution, and calculate the average. The lead in the extraction solution must be expressed in /mL, and the result is expressed in formula (2) Calculation:
A-Ar
()+
A—A.
In the formula: C-the content of lead or cadmium in the extraction solution + the absolute absorption value of μg/mLA extraction solution lead or cadmium;
A,—the absolute absorption value of the lower concentration standard solution lead or cadmium : Absolute absorption value of higher concentration standard solution lead or solution: A,
C2--content of higher concentration standard solution lead or solution+μg/mL, Ci
lower concentration standard solution lead Or content, ug/mL. Note: If the extract is diluted, multiply by the dilution factor. 3.6.4 Standard curve method
(2)
Spray the standard solution of 3.2.6 or 3.2.9 on the atomic absorption spectrophotometer, and record the concentration of the standard contact solution and the corresponding concentration The absolute absorption value A. Draw a standard curve with the absolute absorption A obtained from the standard solution as the ordinate and the relative content of lead and manganese (/mL) as the abscissa. Find the lead and cadmium concentration of the extraction solution directly from the standard curve, expressed in g/mL. During the operations according to 3.6.2 to 3.6.4, the zero point must be calibrated with reagent blank. 3.7 The effective values ??of the test results
are accurate to 0.1pg/mL for the lead dissolution amount
are accurate to 0.01μg/mL for the cadmium dissolution amount. 4 Test accuracy
This accuracy refers to the degree of random error, and its repeatability and reproducibility do not exceed the values ??specified in the table below. Range (μg/mL)
Lead 0.481.9
10
116
Nasal regeneration
0.69
0.01||tt ||Reproducibility
1.63
0.01
5 Test report
Sample number
Additional instructions:
Sample delivery unit:
Condensation test item,
Sample delivery date:
Protection unit:
Test date:
GB 8058--87
Lead in ceramic cookers, measured value of outflow measurement report
Lead
g/mt.
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the Ceramics Research Institute of the Ministry of Light Industry. This standard is drafted by the Tengci Research Institute of the Ministry of Light Industry. The main drafter of this standard is Li Miaoliang.
Cadmium
ag/mL
Sample name:
Number of samples:
Measurement conditions:
Detected nitrogen: ||tt| |Floor:
Prepare
Note
117
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