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This standard replaces GB/T 23296.4-2009 Food Contact Materials - Polymer - Determination of 1-octene and Tetrahydrofuran in Food Simulants - Gas Chromatography.
The following changes have been made with respect to GB/T 23296.4-2009 (the previous edition):
——This standard is renamed as "National Food Safety Standard - Food Contact Materials and Articles - Determination of Migration of 1-octene and Tetrahydrofuran";
——Gas chromatography-mass spectrometry is added;
——Preparation of food simulant test solution is modified;
——The expression of analysis results is modified;
——The detection limit and the quantitation limit are modified.
National Food Safety Standard
Food Contact Materials and Articles
Determination of Migration of 1-octene and Tetrahydrofuran
1 Scope
This standard specifies the determination method for migration of 1-octene and tetrahydrofuran in food contact materials and articles.
This standard is applicable to determination of migration of 1-octene and tetrahydrofuran in food contact materials and articles.
Method I Gas Chromatography
2 Principle
Samples of 1-octene and tetrahydrofuran in food simulants, after subjected to headspace injection, separate from internal standard and other components in the chromatographic column; detect with hydrogen flame ionization detector and carry out quantitative determination by internal standard method.
3 Reagents and Materials
Unless otherwise specified, analytically-pure reagents and Class-I water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 N,N-dimethyl acetamide (DMAC, C4H9NO): purity > 99.0%.
3.1.2 Water-based, acidic, alcoholic and oil-based food simulants: the reagents used shall be in accordance with the requirements of GB 31604.1.
3.2 Preparation of reagents
3.2.1 Water-based, acidic, alcoholic and oil-based food simulants: prepare according to GB 5009.156.
3.3 Standard products
3.3.1 1-octene (C8H16; CAS No.: 111-66-0): with purity ≥99.5%, or reference material approved and awarded with reference material certificate by the State.
3.3.2 Isooctane (C8H18; CAS No.: 540-84-1): with purity ≥99.5%, or reference material approved and awarded with reference material certificate by the State.
3.3.3 Tetrahydrofuran (THF, C4H8O; CAS No.: 109-99-9): with purity ≥98.0%, or reference material approved and awarded with reference material certificate by the State.
3.3.4 Tetrahydropyrane (THP, C5H10O; CAS No.: 142-68-7): with purity ≥99.9%, or reference material approved and awarded with reference material certificate by the State.
3.4 Preparation of standard solutions
3.4.1 1-octene standard stock solution (2mg/mL): take 45mL of DMAC and pour it into 50mL volumetric flask, and weigh the volumetric flask with stopper (to the nearest of 0.0001g); add 100 mgof 1-octene (about 150μL), weigh it again (to the nearest of 0.0001g); scale the volume with DMAC, and accurately calculate the concentration of 1-octene; preserve it from light at 4℃, and the validity period is 3 months.
3.4.2 1-octene standard intermediate solution (200μg/mL): accurately take 1.0mL of 1-octene standard stock solution and pour it into a 10mL volumetric flask, and scale the volume with DMAC; preserve it in the same condition as that in 3.4.1.
3.4.3 1-octene standard working solution with medium of water-based, acidic or alcoholic food simulant: respectively pipette 1.0 mL of water-based, acidic and alcoholic food simulants with pipet and pour them into six headspace bottles, and seal them with isolation pads and aluminium caps immediately; add 200 μL of isooctane internal intermediate solutions with microinjector by penetrating the isolation pad, and mix uniformly; add 1-octene standard intermediate solutions and DMAC into the bottles with microinjector by penetrating the isolation pad according to those specified in Table A.1 in Annex A, and mix uniformly.
3.4.4 1-octene standard working solution with medium of olive oil: respectively weigh 1g (to the nearest of 0.01g) of olive oil and put them into six headspace bottles, immediately seal them with isolation pads and aluminium caps, add 200 μL of isooctane internal standard intermediate solutions in sequence with microinjector by penetrating the isolation pad, and mix uniformly; add into the bottles 1-octene standard intermediate solutions and DMAC with the same volume as that of solution in corresponding bottle according to those listed in Table A.1 in Annex A, and mix uniformly.
3.4.5 Isooctane internal standard stock solution (2mg/mL): measure 45mL of DMAC and pour it into 50mL volumetric flask, and weigh the volumetric flask with stopper (to the nearest of 0.001g); add 100mg of isooctane (about 150μL), weigh it again (to the nearest of 0.0001g), and scale the volume with DMAC; accurately calculate the concentration of isooctane; preserve it in the same condition as that in 3.4.1.
3.4.6 Isooctane internal standard intermediate solution (120μg/mL): take 3.0mL of isooctane internal standard stock solution and pour it into a 50mL volumetric flask, and scale the volume with DMAC; preserve it in the same condition as that in 3.4.1.
3.4.7 Water-based, acidic or alcoholic THF standard stock solution (2.2 mg/mL): measure 99 mL of water and pour it into a 100mL volumetric flask and weigh the volumetric flask with stopper (to the nearest of 0.0001g); add 220mg of THF (about 250μL) and weigh it again (to the nearest of 0.0001g), scale the volume with water, and accurately calculate the concentration of THF; preserve it from light at 4℃ and the validity period is 1 week.
3.4.8 Water-based, acidic or alcoholic THF standard intermediate solution (22 μg/mL): measure 90 mL of water and pour it into a 100mL volumetric flask, add into 1.0 mL of water-based THF standard stock solution, scale the volume with water and preserve it in the same condition as that in 3.4.7.
3.4.9 THF standard working solution with medium of water-based, acidic or alcoholic food simulant: respectively measure 45 mL of water-based, acidic and alcoholic food simulants and pour them into six 50mL volumetric flask, add water-based, acidic or alcoholic THF standard intermediate solution with certain volume correspondingly according to those specified in Table A.2, and scale the volume with corresponding food simulants.
Accurately take 10.0mL of the above-mentioned solutions respectively and pour them into six headspace bottles, seal them with isolation pads and aluminium caps immediately, pipette 100μL of water-based, acidic or alcoholic THP internal standard intermediate solution with microinjector and add it into corresponding headspace bottle by penetrating the isolation pad, and mix uniformly.
3.4.10 Water-based, acidic or alcoholic THP internal standard stock solution (1 mg/mL): measure 99 mL of water and pour it into a 100mL volumetric flask, and weigh the volumetric flask with stopper (to the nearest of 0.0001g); add 100mg of THP (about 150 μL) and weigh it again (to the nearest of 0.0001g), scale the volume with water, accurately calculate the concentration of THP and preserve it in the same condition as that in 3.4.7.
3.4.11 Water-based, acidic or alcoholic THP internal standard intermediate solution (70 μg/mL): measure 90 mL of water and pour it into a 100mL volumetric flask, add into 7.0 mL of water-based THP internal standard stock solution, scale the volume with water and preserve it in the same condition as that in 3.4.7.
3.4.12 Oily THF standard stock solution (1.0 mg/mL): measure 45 mL of DMAC and pour it into a 50mL volumetric flask and weigh the volumetric flask with stopper (to the nearest of 0.0001 g); add 50 mg of THF (about 60μL) and weigh it again (to the nearest of 0.0001g), scale the volume with DMAC, and accurately calculate the concentration of THF; preserve it in the same condition as that in 3.4.7.
3.4.13 Oily THF standard intermediate solution (50 μg/mL): take 1.0 mL of oily THF standard stock solution and pour it into a 20mL volumetric flask, and scale the volume with DMAC; preserve it in the same condition as that in 3.4.7.
3.4.14 THF standard working solution with medium of olive oil: respectively weigh 10g (to the nearest of 0.01g) of olive oils and put them into six headspace bottles, seal the bottles with isolation pads and aluminium caps immediately, pipette 100μL of oily THP internal standard intermediate solutions with microinjector and add them into headspace bottles respectively, add oily THF standard intermediate solutions and DMAC with certain volume into each headspace bottle according to those specified in Table A.3 to prepare standard working solutions with the concentration similar to those listed in Table A.3.
3.4.15 Oily THP internal standard stock solution (1 mg/mL): take 45 mL of DMAC and pour it into a 50mL volumetric flask and weigh the volumetric flask with stopper (to the nearest of 0.0001 g); add 50 mg of THP (about 60μL) and weigh it again (to the nearest of 0.0001g), scale the volume with DMAC, and accurately calculate the concentration of THP; preserve it in the same condition as that in 3.4.7.
3.4.16 Oily THP internal standard intermediate solution (75 μg/mL): take 1.5 mL of oily THP internal standard stock solution and pour it into a 20mL volumetric flask, and scale the volume with DMAC; preserve it in the same conditions as that in 3.4.7.
4 Instruments and Apparatus
4.1 Gas chromatograph: equipped with automatic headspace sampler and hydrogen flame ionization detector (FID).
4.2 Headspace bottle: 20mL; equipped with aluminium cap and butyl rubber or silicone resin rubber isolation pad whose side contacting sample shall be coated with polytetrafluoroethylene.
Note: THF may be used for manufacturing the butyl rubber isolation pad with its inside coated with polytetrafluoroethylene, which may seriously interfere with the THF analysis; thus, before test, the isolation pad shall be subjected to purification treatment, i.e. boil it for at least 15 min with distilled water and then dry it in the air; isolation pads which are purified and unused shall be purified again when used in the next time.
4.3 Volumetric flask: 10mL, 25mL, 50mL and 100mL.
4.4 Microinjector: 25μL, 50μL, 100μL, 250μL and 500μL.
4.5 Pipet: 1mL, 2mL, 3mL, 5mL and 10mL.
4.6 Analytical balance: with sensibility of 0.0001g and 0.01g.
5 Analysis Steps
5.1 Preparation of specimen
Carry out migration test for the sample according to the requirements of GB 5009.156 and GB 31604.1 so as to obtain food simulant test solution; if the food simulant test solution obtained cannot be used immediately for the next step of test, it shall be preserved from light at in a 0℃~4℃ refrigerator.
The food simulant test solution obtained shall be cooled or recovered to room temperature before being used for the next step of test.
5.2 Preparation of test solutions
5.2.1 Preparation of water-based, acidic or alcoholic food simulant test solution used for 1-octene determination
Transfer 1.0mL of water-based food simulant from migration test and pour it into a headspace bottle, and seal the bottle with isolation pad and aluminium cap immediately; add 200μL of isooctane internal standard intermediate solution and 200μL of DMAC in sequence with microinjector by penetrating the isolation pad, and mix uniformly.
5.2.2 Preparation of food simulant test solution with medium of olive oil used for 1-octene determination
Weigh 1g (to the nearest of 0.01g) of olive oil medium food simulant from migration test and put it into a headspace bottle, and then operate according to the operation steps in 5.2.1 from "and seal the bottle with isolation pad and aluminium cap immediately… …".
5.2.3 Preparation of water-based, acidic or alcoholic food simulant test solution used for tetrahydrofuran determination
Pipette 10.0mL of water-based, acidic or alcoholic food simulant from migration test and pour it into a headspace bottle, and seal the bottle with isolation pad and aluminium cap immediately; add 100μL of water-based, acidic or alcoholic THP internal standard intermediate solution correspondingly with microinjector by penetrating the isolation pad, and mix uniformly.
5.2.4 Preparation of food simulant test solution with medium of olive oil used for tetrahydrofuran determination
Weigh 10g (to the nearest of 0.01g) of olive oil medium food simulant from migration test and put it into a headspace bottle, and seal the bottle with isolation pad and aluminium cap immediately; add 100 μL of oily THP internal standard intermediate solution (3.4.16) and then 300μL of DMAC rapidly with microinjector by penetrating the isolation pad, and mix uniformly.
5.3 Preparation of blank test solution
Treat the food simulants which have not contacted the food contact materials and articles according to the procedures described in 5.2.
Foreword i
1 Scope
2 Principle
3 Reagents and Materials
4 Instruments and Apparatus
5 Analysis Steps
6 Expression of Analysis Result
7 Accuracy
8 Others
9 Principle
10 Reagents and Materials
11 Instruments and Apparatus
12 Analysis Steps
13 Expression of Analysis Result
14 Accuracy
15 Others
Annex A Table for Standard Working Solution Preparation
Annex B Standard Product Spectrogram in Gas Chromatography and Gas Chromatography-mass Spectrometry
