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This standard replaces GB/T 5009.152-2003 Determination of Residual Acrylonitrile Monomer in Styrene-acrylonitrile Copolymers and Rubber-modified Acrylonitrile-butadiene-styrene Resins and Their Products Used for Foods Packaging, GB/T 23296.8-2009 Food Contact Materials - Polymer - Determination of Acrylonitrile in Food Simulants - Gas Chromatography and SN/T 2197-2008 Food Contact Materials - Polymer Materials - Determination of Acrylonitrile in Food and Food Simulants - Gas Chromatography.
The following main changes have been made with respect to GB/T 5009.152-2003:
——The standard name is revised as National Food Safety Standard - Food Contact Materials and Articles - Determination of Acrylonitrile and Migration;
——Gas chromatography-hydrogen flame detector method is deleted while gas chromatography nitrogen-phosphorous detector method is retained;
——Determination of acrylonitrile migration in food contact materials and articles is added.
National Food Safety Standard
Food Contact Materials and Articles - Determination of Acrylonitrile and Migration
1 Scope
This standard specifies the determination method of acrylonitrile and migration in food contact materials and articles.
This standard is applicable to the determination of acrylonitrile and migration in food contact materials and articles.
Determination of Acrylonitrile
2 Principle
Dissolve or disperse the food contact materials and articles with N, N-dimethyl formamide in a headspace bottle, heat to make the to-be-tested constituent reach gas-liquid equilibrium and then pipet headspace air quantitatively to carry out gas chromatograph determination. Qualify as per retention time and quantify as per internal standard method with propionitrile as internal standard substance.
3 Reagents and Materials
Class-I water (defined in GB/T 6682) is adopted for the purpose of this method. The plastic material shall not be used for the container and transferring tool in the test.
3.1 Reagent
N, N-dimethyl formamide (DMF): analytical reagent, free of interference peak within the range of retention time of acrylonitrile and propionitrile.
3.2 Standard products
3.2.1 Acrylonitrile (C3H3N, CAS No.: 107-13-1): 1000μg/mL, or reference material approved and awarded with reference material certificate by the State.
3.2.2 Propionitrile (C2H5CN, CAS No.: 107-12-0): 1000μg/mL, or reference material approved and awarded with reference material certificate by the State.
3.3 Preparation of standard solutions
3.3.1 Acrylonitrile standard working solution
Pipet 0.1mL, 0.2mL, 0.3mL, 0.4mL and 0.5mL acrylonitrile standard product and respectively transfer into 10mL volumetric flasks, dilute with N, N-dimethyl formamide to the scale, mix uniformly (each milliliter is equivalent to 10μg, 20μg, 30μg, 40μg and 50μg acrylonitrile) and prepare on the day of being used.
3.3.2 Propionitrile standard solution
Pipet 0.5mL propionitrile standard product to transfer into a 10mL volumetric flask, dilute with N, N-dimethyl formamide to the scale, mix uniformly and obtained propionitrile standard solution with concentration of 50μg/mL.
4 Instruments and Apparatus
4.1 Gas chromatograph (with nitrogen-phosphorous detector).
4.2 Headspace automatic sample injector.
4.3 20mL headspace air determination bottle, with rubber cap coated with polyvinyl fluoride silicon and aluminum cap.
4.4 Analytical balance: with sensibility of 0.1mg.
4.5 10mL volumetric flask.
4.6 250μL microinjector.
5 Analysis Steps
5.1 Preparation of specimen
Take 10g representative food packaging materials, grind with grinder or cut with scissors into fragment with particle size less than or equal to 0.2cm, mix uniformly and put into a clean container.
5.2 Preparation of test solution
Weigh 0.5g (accurate to 0.01g) specimen and put into a headspace bottle, add 5.0mL N, N-dimethyl formamide and then cover the bottle immediately, add 200μL propionitrile standard solution into a headspace bottle with a 250μL microinjector, shake fully to make the specimen in bottle fully dissolved or dispersed for testing. Carry out blank test simultaneously.
5.3 Reference conditions of instruments
5.3.1 Conditions of headspace sample injector
Conditions of headspace sample injector are as follows:
a) Equilibrium time: 30min;
b) Furnace temperature: 80℃;
c) Pressure: 138kPa;
d) Pressure time: 2min;
e) Sample injection time: 0.04 min;
f) Temperature of transmission line: 85℃.
5.3.2 Gas chromatographic conditions
Gas chromatographic conditions are as follows:
a) Chromatographic column: cross-linked polyethylene glycol stationary phase capillary chromatographic column (length: 30m; inside diameter: 0.32mm; film thickness: 0.25μm) or equivalent column;
b) Column temperature program: keep 4min under 40℃, rise to 70℃ at the rate of 10℃/min and keep for 1min, and then rise to 170℃ at the rate of 15℃/min.
c) Temperature of injection port: 150℃;
d) Temperature of detector: 280℃;
e) Flow rate of nitrogen as carrier gas: 50mL/min;
f) Flow rate of hydrogen: 1.5mL/min;
g) Flow rate of air: 145mL/min;
h) Sample injection from injection port under constant pressure: 100kPa.
5.4 Preparation of calibration solution and plotting of calibration curve
Take 5 headspace bottles and respectively add 200μL propionitrile standard solution into them, and add acrylonitrile series of standard solutions successively, then the acrylonitrile content in calibration solution is respectively equivalent to 2.0μg, 4.0μg, 6.0μg, 8.0μg and 10.0μg. Adjust the gas chromatograph to the optimal working state, place the headspace bottles containing standard series into headspace sample injector, take the gas above solution into the gas chromatograph for determination to obtain corresponding chromatographic peaks of propionitrile and acrylonitrile. Plot calibration curve with acrylonitrile content as the x-axis and the ratio of peak area of acrylonitrile to that of propionitrile as y-axis.
See Figure A.1 for the gas chromatogram of acrylonitrile.
5.5 Determination of specimen solution
Adjust the gas chromatograph to the optimal working state, place the headspace bottle containing to-be-tested test solution into headspace sample injector, take the gas above solution into the gas chromatograph for determination to obtain corresponding chromatographic peaks of acrylonitrile and propionitrile, and qualify as per the retention time quantify as per the peak area ratio of acrylonitrile in the specimen to propionitrile in internal standard substance.
Foreword i
1 Scope
2 Principle
3 Reagents and Materials
4 Instruments and Apparatus
5 Analysis Steps
6 Expression of Analysis Results
7 Accuracy
8 Other
9 Principle
10 Reagents and Materials
11 Instruments and Apparatus
12 Analysis Steps
13 Expression of Analysis Results
14 Accuracy
15 Other
Annex A Gas Chromatogram of Acrylonitrile
