GB/T 5009.152-2003 Determination of residual acrylonitrile monomer in styrene-acrylonitrile copolymers and rubber-modified acrylonitrile-butadiene-styrene resins for food packaging and their molded products
Some standard content:
ICS67.040
National Standard of the People's Republic of China
GB/T5009.152—2003
Replaces GB/T17338-1998
Determination of residual acrylonitrile monomer instyrene-acrylonitrile copolymers and rubber-modified acrylonitrile-butadiene-styrene resins and their productsused forfood packaging2003-08-11 Issued
Ministry of Health of the People's Republic of China
Standardization Administration of China
2004-01-01 Implementation
GB/T5009.152-2003
This standard replaces GB/T173381998 "Determination of residual acrylonitrile monomer in styrene-propylene copolymer and rubber-modified acrylonitrile-butadiene styrene resin for food packaging and its molded products". This standard modifies the structure of the original standard in accordance with GB/T20001.4-2001 "Standard Preparation Rules Part 4: Chemical Analysis Methods".
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. The responsible drafting units of the first method of this standard are: Shanghai Gaoqiao Petrochemical Company Chemical Plant, Shanghai Health and Epidemic Prevention Station. The responsible drafting units of the second method of this standard are: Shanghai Health and Epidemic Prevention Station, Guangxi Zhuang Autonomous Region Food Hygiene Supervision and Inspection Institute, Shanghai Luwan District Health and Epidemic Prevention Station.
The main drafters of the first method of this standard are: Wu Keqin, Wang Junfu, Dong Jianfang, Pan Xihe. The main drafters of the second method of this standard are: Zhu Yingmin, Shen Wen, Ye Bisha, Lao Baofa. The original standard was first issued in 1998, and this is the first revision. 279
GB/T5009.152--2003
This standard is divided into the first method (NPD method) and the second method (FID method). This standard refers to ASTM4322-83 (1991) "Standard test method for determination of residual acrylonitrile monomer in styrene-acrylonitrile copolymer and wax rubber by headspace gas chromatography" and ISO4581:1994 "Gas chromatography determination of propylene monomer residues in plastic products of styrene-acrylonitrile copolymer". It draws on its determination principle and main technical content. However, the specific determination conditions and processes have been adjusted and changed to make this standard more suitable for the actual situation in my country. 280
1 Scope
Determination of residual propylene monomer in styrene-acrylonitrile copolymer and rubber-modified acrylonitrile-butadiene-styrene resin for food packaging and their molded products
GB/T5009.152—2003
This standard specifies the method for determining residual acrylonitrile in acrylonitrile-styrene copolymer (AS) and acrylonitrile-butadiene-styrene copolymer (ABS) by headspace gas chromatography (HP-GC). This standard is applicable to the determination of residual acrylonitrile monomer in acrylonitrile-styrene and acrylonitrile-butadiene-styrene resin and their molded products, and also to the determination of residual acrylonitrile monomer in rubber-modified acrylonitrile-butadiene-styrene resin and its molded products. The detection limit of this method is 0.5 mg/kg for nitrogen-phosphorus detector (NPD) and 2.0 mg/kg for hydrogen flame detector (FID). Method 1 Gas Chromatography Nitrogen-Phosphorus Detector (NPD) 2 Principle
Place the sample in a headspace bottle, add a solvent containing a known amount of internal standard propylene nitrile (PN), seal it immediately, heat the headspace bottle to achieve gas-liquid equilibrium after it is fully dissolved, and quantitatively draw the headspace gas for chromatography (NPD) determination, and quantify according to the response value of the internal standard. 3 Reagents
3.1 Purity of reagents: Analytical grade reagents should be used for this test. If other levels of reagents are used, they must have a high enough purity so as not to reduce the accuracy of the determination.
3.2 Solvent: N, N-dimethylformamide or N, N-dimethylacetamide (DMA). When the headspace gas of the solvent is chromatographically determined, no interference peaks should appear at the retention time of propylene nitrile (AN) and propylene nitrile (PN). 3.3 Propyl ester: chromatographic grade.
3.4 Acrylonitrile: chromatographic grade.
4 Instruments
4.1 Gas chromatograph
Should be equipped with nitrogen-phosphorus detector.
It is best to use a device with automatic collection of analytical air. If the headspace is collected and analyzed manually, the following equipment should be added: 4.1.1 Constant temperature bath, which can maintain 90℃±1℃. 4.1.2 Airtight syringe for collecting and injecting headspace air. 4.2 Headspace bottle sealer.
4.3 5.0mL headspace sampling bottle.
4.4 Aluminum sealing bottle cap.
4.5 Butyl rubber or silicone rubber with good airtightness and inner surface covered with polytetrafluoroethylene film. 281
GB/T5009.152—2003
5 Analysis steps
5.1 Calibration by internal standard method
5.1.1 Prepare a polymer solution containing a known amount of internal standard (PN). 5.1.2 Use a 100mL volumetric flask and fill it with an appropriate amount of solution (3.2) in advance. Accurately weigh about 10mg of PN, dilute it to the mark with solvent (3.2), and shake well. Calculate the concentration of PN in this solution A (mg/mL). 5.1.3 Accurately transfer 15.0mL of solution A to a 250ml volumetric flask, dilute it to the volume mark with solvent (3.2), and shake well. This solution is prepared once a month. Calculate the concentration of PN in solution B as follows (see formula 1): C
Where:
GA×15
The concentration of PN in solution B is in milligrams per liter (mg/mL): CA
Ca—The concentration of PN in solution A is in milligrams per milliliter (mg/mL). (1)
5.1.4 Accurately weigh about 150 mg of acrylonitrile (AN) into a 50 mL volumetric flask that has been pre-filled with an appropriate amount of solvent (3.2). Dilute to the volume mark with solvent (3.2), shake well, and calculate the concentration of AN in solution C (mg/mL). This solution is prepared once a month. 5.1.5 Transfer 5.0 ml of solution B into each of the three headspace vials and seal them with gaskets and aluminum caps. 5.1.6 Use a calibrated syringe to accurately inject 10 L of solution C into each bottle through the gasket and shake well. Use as the working standard solution. 5.1.7 Calculate the content of AN (m) and PN (m,) in the working standard solution (5.1.6), see formula (2) and formula (3). mI = V.XCAN
Where:
The content of AN in the working standard solution, in milligrams (mg); m
V. The volume of solution C, in milliliters (mL): CAs—The concentration of AN in solution C, in milligrams per milliliter (mg/mL). M,=VXCPN
Where:
m. The content of PN in the working standard solution, in milligrams (mg); Vs——The volume of solution B, in milliliters (mL) Cps—The concentration of PN in solution B, in milligrams per milliliter (mg/mL). .(2)
(3)
5.1.8 According to the operating conditions recommended in 5.3 and the same conditions as the operating procedures described in 5.2 and 5.4, extract 2.0mL of the working standard solution (5.1.6) and inject it into the gas chromatograph. Based on the peak area A of AN and the peak area A of PN, as well as their known amounts (5.1.7), determine the correction factor R according to formula (4): m.XA.
Where:
R——correction factor;
m.——the content of AN in the working standard solution, in milligrams (mg); A,—the peak area of PN
m.——the content of PN in the working standard solution, in milligrams (mg); A—the peak area of AN.
Example:
Acrylonitrile (AN)
Propanonitrile (PN)
5.2 Sample processing
Mass (mg)
0.030X22282
0.030×21633
Peak area (integral count)
GB/T5009.152—2003
All samples should be stored in sealed bottles. The prepared sample solution should be analyzed within 24 hours. If it exceeds 24 hours, the storage time of the solution should be reported.
5.2.1 Fully mix the sample to be tested so that the selected sample is representative enough, weigh 0.5g±0.005g sample in the empty bottle, record the sample mass.
5.2.2 Add 5.0mL solution B (5.1.3) to the headspace bottle. After covering with a gasket and an aluminum cap, shake thoroughly to completely dissolve or fully disperse the polymer in the bottle.
5.3 Gas chromatography conditions
5.3.1 Chromatographic column: 3mm×4m stainless steel column. Filled with 101 white acidic support (60 mesh to 80 mesh) coated with 15% polyethylene glycol-20M. 5.3.2 Temperature
Column temperature: 130℃,
Vaporization temperature: 180℃;
Detector temperature: 200℃.
5.3.3 Gas velocity
Carrier gas nitrogen (N) flow rate: 25mL/min~3UmL/min. 5.3.4 Other conditions
Nitrogen 99.95% or higher purity.
Hydrogen dried and purified.
Air dried and purified.
5.4 Determination
Place the headspace bottle in a 90℃ bath for thermal equilibrium for 50 minutes. Use a heated gas syringe to extract 2.0mL of headspace air that has reached gas-liquid equilibrium from the bottle and immediately inject it into the gas chromatograph for determination. The operating conditions of the gas chromatograph are set as described in 5.3. If a commercial instrument for automatic headspace analysis is used, adjust it according to the instrument's manual. 5.5 Calculation of results
The residual propylene content in the sample (c+mg/kg) is calculated according to formula (5): mxA\xRx1000
Wherein:
-sample content, in milligrams per kilogram (mg/kg); -peak area or integrated count of AN in the sample solution; A.
-peak area or integrated count of PN in the sample solution; (5)
GB/T5009.152—2003
m, -amount of PN in the sample solution, in milligrams (mg); mass of the sample, in grams (g).
For example,
A-35416 (integrated count)
A, -25112 (integrated count)
0.030X35416X1.03×100087.2mg/kg25112X0.5000
5.6Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. Second method Gas chromatography hydrogen flame detector method (FID) 6 Principle
The sample is dissolved in the air measuring bottle with N, N-dimethylformamide solvent, heated to make the component to be measured reach gas-liquid equilibrium, and then the air is drawn for chromatography (FID) determination. Qualitative analysis is based on retention time, and quantitative analysis is compared with standard peak height. 7 ReagentsbZxz.net
7.1N, N-dimethylformamide (DMF): analytically pure, there should be no interference peak at the retention time of acrylonitrile. 7.2 Acrylonitrile (AN): analytical grade.
7.3 GDX-102 (60 days to 80 days).
7.4 Acrylonitrile standard stock solution: weigh 0.0500g of propylene essence, add N,N-dimethylformamide to dilute to 50mL, this stock solution is equivalent to 1.0mg of propylene per milliliter, store in a refrigerator. 7.5 Acrylonitrile standard working solution: draw 0.2, 0.4, 0, 6, 0.8, 1.6mL of stock solution. Transfer to 10mL volumetric flasks respectively, add N,N-dimethylformamide to dilute to the scale, mix well (each milliliter is equivalent to 2040, 60, 80, 160μg of acrylonitrile respectively). 8 Instruments
8.1 Gas chromatograph (with hydrogen flame detector). 8.21mL middle-head glass syringe.
8.312mL headspace gas determination bottle; equipped with a polyfluoroethylene silicone rubber cover and an aluminum cap. 8.4 Electric constant temperature water bath.
9 Analysis steps
All samples should be stored in sealed bottles. The prepared sample solution should be analyzed within 24 hours. If it exceeds 24 hours, the storage time of the solution should be reported.
9.1 Sample treatment
Weigh 0.5g1g (accurate to 0.001g) of uniform sample into the headspace gas determination bottle, add 3mLN,N-dimethylformamide, immediately cover and seal, and test after the sample is dissolved. 9.2 Gas chromatography conditions
9.2.1 Chromatographic column: Φ4mm×2m glass column. Filled with GDX-102 (60 mesh~80 mesh). 9.2.2 Temperature
Column temperature: 170℃:
Vaporization temperature: 180℃:
Detector temperature: 220℃.
9.2.3 Gas velocity
Carrier gas nitrogen (N,) flow rate: 40mL/min; hydrogen flow rate: 44mL/min,
Air flow rate: 500mL/min.
9.2.4 Other conditions
Instrument sensitivity: 10°,
Attenuation: 1;
Paper speed: 0.7cm/min.
9.3 Determination
CB/T5009.152—2003
9.3.1 Adjust the gas chromatograph to the best working state (refer to 9.2), put the sample bottle to be tested into a 90℃±1℃ water bath and heat it accurately for 40min, take 1.0mL of the gas above the liquid and inject it into the chromatograph. If necessary, the amount of headspace gas taken can be adjusted to adapt to the determination of samples with different contents. 9.3.2 Preparation of standard curve: First, add 3.0mL of N,N-methylformamide to each of the 5 headspace gas bottles, and then take 0.2mL of the standard working liquid series (7.5) and add them to the determination bottles respectively. At this time, the acrylonitrile content in each determination bottle is equivalent to 4, 8, 12, and 16.32μg respectively. Immediately seal the bottle cap, mix well, and place it in a 90℃ water bath. The following determination is the same as the sample, that is, take 1.0mL of headspace gas respectively. Inject into the chromatograph and measure the peak height. Draw a standard curve with the acrylonitrile content as the horizontal axis and the peak height as the vertical axis, and quantify according to the peak height of the sample. 9.4 Calculation of results
See formula (6).
A×1000
mx1000
Where:
X—the content of acrylonitrile in the sample, in milligrams per kilogram (mg/kg); A—the content equivalent to the standard, in micrograms (ug); m
the mass of the sample, in grams (g).
9.5 Precision
The absolute difference between two independent measurement results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. (6)6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. Second method Gas chromatography hydrogen flame detector method (FID) 6 Principle
The sample is dissolved in the air measuring bottle with N, N-dimethylformamide solvent, heated to make the component to be measured reach gas-liquid equilibrium, and then the air is drawn for chromatography (FID) determination. Qualitative analysis is based on retention time, and quantitative analysis is compared with standard peak height. 7 Reagents
7.1N, N-dimethylformamide (DMF): analytically pure, there should be no interfering peak at the retention time of acrylonitrile. 7.2 Acrylonitrile (AN): analytically pure.
7.3 GDX-102 (60 days~80 days).
7.4 Acrylonitrile standard stock solution: weigh 0.0500g of propylene essence, add N,N-dimethylformamide to dilute to 50mL, this stock solution is equivalent to 1.0mg of propylene per milliliter, store in a refrigerator. 7.5 Acrylonitrile standard working solution: draw 0.2, 0.4, 0, 6, 0.8, 1.6mL of stock solution. Transfer to 10mL volumetric flasks respectively, add N,N-dimethylformamide to dilute to scale, mix well (each milliliter is equivalent to 2040, 60, 80, 160μg of acrylonitrile respectively). 8 Instruments
8.1 Gas chromatograph (with hydrogen flame detector). 8.21mL middle-head glass syringe.
8.312mL headspace determination bottle; equipped with polyvinyl fluoride silicone rubber cover and aluminum sheet cap. 8.4 Electric constant temperature water bath.
9 Analysis steps
All samples should be stored in sealed bottles. The prepared sample solution should be analyzed within 24 hours. If it exceeds 24 hours, the storage time of the solution should be reported.
9.1 Sample treatment
Weigh 0.5g1g (accurate to 0.001g) of uniform sample into a headspace measurement bottle, add 3mLN,N-dimethylformamide, immediately cover and seal, and wait for the sample to dissolve and then test. 9.2 Gas chromatography conditions
9.2.1 Chromatographic column: Φ4mm×2m glass column. Filled with GDX-102 (60 mesh~80 mesh). 9.2.2 Temperature
Column temperature: 170℃:
Vaporization temperature: 180℃:
Detector temperature: 220℃.
9.2.3 Gas velocity
Carrier gas nitrogen (N2) flow rate: 40mL/min; hydrogen flow rate: 44mL/min,
Air flow rate: 500mL/min.
9.2.4 Other conditions
Instrument sensitivity: 10°,
Attenuation: 1;
Paper speed: 0.7cm/min.
9.3 Determination
CB/T5009.152—2003
9.3.1 Adjust the gas chromatograph to the best working state (refer to 9.2), put the sample bottle to be tested into a 90℃±1℃ water bath and heat it accurately for 40min, take 1.0mL of the gas above the liquid and enter the chromatograph, and adjust the amount of headspace gas taken if necessary to adapt to the determination of samples with different contents. 9.3.2 Preparation of standard curve: First, add 3.0mL of N,N-methylformamide to each of the 5 headspace vials, then take 0.2mL of the standard working solution series (7.5) and add them to the test vials. At this time, the acrylonitrile content in each test vial is equivalent to 4, 8, 12, and 16.32μg, respectively. Immediately seal the vial cap, mix well, and place in a 90℃ water bath. The following is the same as the sample determination, that is, take 1.0mL of headspace gas. Inject into the chromatograph and measure the peak height. Draw a standard curve with the acrylonitrile content as the horizontal axis and the peak height as the vertical axis, and quantify according to the peak height of the sample. 9.4 Calculation of results
See formula (6).
A×1000
mx1000
Wherein:
X is the content of acrylonitrile in the sample, in milligrams per kilogram (mg/kg); A is the content equivalent to the standard, in micrograms (ug); m
is the mass of the sample, in grams (g).
9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. (6)6 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. Second method Gas chromatography hydrogen flame detector method (FID) 6 Principle
The sample is dissolved in the air measuring bottle with N, N-dimethylformamide solvent, heated to make the component to be measured reach gas-liquid equilibrium, and then the air is drawn for chromatography (FID) determination. Qualitative analysis is based on retention time, and quantitative analysis is compared with standard peak height. 7 Reagents
7.1N, N-dimethylformamide (DMF): analytically pure, there should be no interfering peak at the retention time of acrylonitrile. 7.2 Acrylonitrile (AN): analytically pure.
7.3 GDX-102 (60 days~80 days).
7.4 Acrylonitrile standard stock solution: weigh 0.0500g of propylene essence, add N,N-dimethylformamide to dilute to 50mL, this stock solution is equivalent to 1.0mg of propylene per milliliter, store in a refrigerator. 7.5 Acrylonitrile standard working solution: draw 0.2, 0.4, 0, 6, 0.8, 1.6mL of stock solution. Transfer to 10mL volumetric flasks respectively, add N,N-dimethylformamide to dilute to scale, mix well (each milliliter is equivalent to 2040, 60, 80, 160μg of acrylonitrile respectively). 8 Instruments
8.1 Gas chromatograph (with hydrogen flame detector). 8.21mL middle-head glass syringe.
8.312mL headspace determination bottle; equipped with polyvinyl fluoride silicone rubber cover and aluminum sheet cap. 8.4 Electric constant temperature water bath.
9 Analysis steps
All samples should be stored in sealed bottles. The prepared sample solution should be analyzed within 24 hours. If it exceeds 24 hours, the storage time of the solution should be reported.
9.1 Sample treatment
Weigh 0.5g1g (accurate to 0.001g) of uniform sample into a headspace measurement bottle, add 3mLN,N-dimethylformamide, immediately cover and seal, and wait for the sample to dissolve and then test. 9.2 Gas chromatography conditions
9.2.1 Chromatographic column: Φ4mm×2m glass column. Filled with GDX-102 (60 mesh~80 mesh). 9.2.2 Temperature
Column temperature: 170℃:
Vaporization temperature: 180℃:
Detector temperature: 220℃.
9.2.3 Gas velocity
Carrier gas nitrogen (N2) flow rate: 40mL/min; hydrogen flow rate: 44mL/min,
Air flow rate: 500mL/min.
9.2.4 Other conditions
Instrument sensitivity: 10°,
Attenuation: 1;
Paper speed: 0.7cm/min.
9.3 Determination
CB/T5009.152—2003
9.3.1 Adjust the gas chromatograph to the best working state (refer to 9.2), put the sample bottle to be tested into a 90℃±1℃ water bath and heat it accurately for 40min, take 1.0mL of the gas above the liquid and enter the chromatograph, and adjust the amount of headspace gas taken if necessary to adapt to the determination of samples with different contents. 9.3.2 Preparation of standard curve: First, add 3.0mL of N,N-methylformamide to each of the 5 headspace vials, then take 0.2mL of the standard working solution series (7.5) and add them to the test vials. At this time, the acrylonitrile content in each test vial is equivalent to 4, 8, 12, and 16.32μg, respectively. Immediately seal the vial cap, mix well, and place in a 90℃ water bath. The following is the same as the sample determination, that is, take 1.0mL of headspace gas. Inject into the chromatograph and measure the peak height. Draw a standard curve with the acrylonitrile content as the horizontal axis and the peak height as the vertical axis, and quantify according to the peak height of the sample. 9.4 Calculation of results
See formula (6).
A×1000
mx1000
Wherein:
X is the content of acrylonitrile in the sample, in milligrams per kilogram (mg/kg); A is the content equivalent to the standard, in micrograms (ug); m
is the mass of the sample, in grams (g).
9.5 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 15% of their arithmetic mean. (6)
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