Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard replaces determination of migration of chromium specified in GB/T 5009.80-2003 Method for Analysis of Hygienic Standard of Polytetrafluorethylene Coating for Inner Wall of Food Container, SN/T 2597-2010 Determination of Lead, Cadmium, Chromium, Arsenic, Antimony, Germanium Migration Quantity in Polymer for Food Contact Materials - Inductively Coupled Plasma Atomic Emission Spectrometry Method and SN/T 2829-2011 Food Contact Materials for Export - Metal Materials - Determination of Migrant Heavy Metals in Food Simulant - Inductively Coupled Plasma Atomic Emission Spectrometric Method.
The following main changes have been made with respect to GB/T 5009.81-2003 (the previous edition):
——This standard is renamed as National Food Safety Standard - Food Contact Materials and Articles-Determination of Migration of Chromium;
——The inductively coupled plasma mass spectrometry is added;
——The inductively coupled plasma emission spectrometry method is added.
National Food Safety Standard
Food Contact Materials and Articles
Determination of Migration of Chromium
1 Scope
This standard specifies graphite furnace atomic absorption spectrometry, inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry method and 1, 5-diphenylcarbohydrazide colorimetry for the determination of migration of chromium in food contact materials and articles after being soaked in food simulants.
This standard is applicable to determination of migration of chromium in food contact materials and articles.
Method I Graphite Furnace Atomic Absorption Spectrometry
2 Principle
Soak the parts of the food contact materials and articles which are expected to contact with food, atomize the soak solution through the graphite furnace; within certain concentration range, the absorption value determined at 357.9 nm is in direct proportion to the chromium content and is compared with standard series for quantification.
3 Reagents and Materials
Unless otherwise specified, guaranteed reagents and Class-II water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.3 Reagents required for preparation of food simulants: in accordance with GB 31604.1.
3.2 Reagent preparation
3.2.1 Food simulants: prepared according to GB 5009.156.
3.2.2 Nitric acid solution (5+95): pipet 5 mL nitric acid, add 950 mL water, and mix uniformly.
3.2.3 Ammonium dihydrogen phosphate solution (20 g/L): weigh 2.0 g ammonium dihydrogen phosphate, dissolve in water and scale the volume to 100 mL.
3.3 Standard product
Potassium bichromate (K2Cr2O7, CAS No.: 7778-50-9): with purity>99.99%, or chromium standard solution with certain concentration approved and awarded with reference material certificate by the State.
3.4 Preparation of standard solution
3.4.1 Chromium standard stock solution (1,000 mg/L): accurately weigh 1.4315 g (accurate to 0.0001 g) potassium bichromate, dissolve in water, transfer into 500 mL volumetric flask, dilute to the scale with nitric acid solution (5+95), and mix uniformly.
3.4.2 Chromium standard intermediate solution (1.00 mg/L): pipet 1.00 mL chromium standard stock solution into 1,000 mL volumetric flask, add nitric acid solution (5+95) to the scale and mix uniformly.
3.4.3 Chromium standard series solution: respectively pipet 0 mL, 0.200 mL, 0.400 mL, 2.00 mL, 0.800 mL, 1.20 mL and 1.60 mL chromium standard intermediate solution into 100 mL volumetric flasks, add corresponding food simulants to the scale and mix uniformly. The series concentrations of this standard solution are 0 μg/L, 2.00 μg/L, 4.00 μg/L, 8.00 μg/L, 12.0 μg/L and 16.0 μg/L.
Note: specific concentration of chromium in standard solution series may be determined according to the sensitivity and linear range of instruments and the actual concentration of chromium in the soak solution. If the selected food simulant is neutral or alkaline, then appropriate nitric acid is required to be added to make the concentration of nitric acid in this solution be about 5% (volume fraction).
4 Instruments and Apparatus
Note: all glasswares shall be soaked in nitric acid solution (1+5) overnight, flushed with tap water repeatedly, and finally washed clean with water.
4.1 Graphite furnace atomic absorption spectrometer: equipped with graphite furnace atomizer and chromium hollow cathode lamp.
4.2 Analytical balance: with sensibility of 0.1 mg.
5 Analysis Steps
5.1 Pretreatment of specimen
Carry out migration test according to the intended use and service conditions of to-be-tested sample and the methods and test conditions for migration test in GB 5009.156 and GB 31604.1. After full mixing of soak solution, take some soaked test solution for analysis. If the soaked test solution is neutral or alkaline, add appropriate amount of nitric acid to make the concentration of nitric acid in this test solution be about 5% (volume fraction). Meanwhile, carry out the specimen blank test.
5.2 Determination
5.2.1 Reference condition of instruments
See Table A.1 for reference conditions of instruments.
5.2.2 Plotting of standard curve
Simultaneously inject 10 μL chromium standard series solution and 5 μL ammonium dihydrogen phosphate solution (20 g/L) (optimum injection volume may be determined according to the adopted instrument) into graphite furnace for determination of absorbance, and plot standard curve with standard series concentration as x-axis and corresponding absorbance as y-axis.
5.2.3 Determination of specimen solution
Simultaneously inject 10 μL blank solution, specimen soak solution and 5 μL ammonium dihydrogen phosphate solution (20 g/L) (optimum injection volume may be determined according to the adopted instrument) into graphite furnace, determine their absorbance value after atomization, compare with standard series for quantification.
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
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard replaces determination of migration of chromium specified in GB/T 5009.80-2003 Method for Analysis of Hygienic Standard of Polytetrafluorethylene Coating for Inner Wall of Food Container, SN/T 2597-2010 Determination of Lead, Cadmium, Chromium, Arsenic, Antimony, Germanium Migration Quantity in Polymer for Food Contact Materials - Inductively Coupled Plasma Atomic Emission Spectrometry Method and SN/T 2829-2011 Food Contact Materials for Export - Metal Materials - Determination of Migrant Heavy Metals in Food Simulant - Inductively Coupled Plasma Atomic Emission Spectrometric Method.
The following main changes have been made with respect to GB/T 5009.81-2003 (the previous edition):
——This standard is renamed as National Food Safety Standard - Food Contact Materials and Articles-Determination of Migration of Chromium;
——The inductively coupled plasma mass spectrometry is added;
——The inductively coupled plasma emission spectrometry method is added.
National Food Safety Standard
Food Contact Materials and Articles
Determination of Migration of Chromium
1 Scope
This standard specifies graphite furnace atomic absorption spectrometry, inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry method and 1, 5-diphenylcarbohydrazide colorimetry for the determination of migration of chromium in food contact materials and articles after being soaked in food simulants.
This standard is applicable to determination of migration of chromium in food contact materials and articles.
Method I Graphite Furnace Atomic Absorption Spectrometry
2 Principle
Soak the parts of the food contact materials and articles which are expected to contact with food, atomize the soak solution through the graphite furnace; within certain concentration range, the absorption value determined at 357.9 nm is in direct proportion to the chromium content and is compared with standard series for quantification.
3 Reagents and Materials
Unless otherwise specified, guaranteed reagents and Class-II water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.3 Reagents required for preparation of food simulants: in accordance with GB 31604.1.
3.2 Reagent preparation
3.2.1 Food simulants: prepared according to GB 5009.156.
3.2.2 Nitric acid solution (5+95): pipet 5 mL nitric acid, add 950 mL water, and mix uniformly.
3.2.3 Ammonium dihydrogen phosphate solution (20 g/L): weigh 2.0 g ammonium dihydrogen phosphate, dissolve in water and scale the volume to 100 mL.
3.3 Standard product
Potassium bichromate (K2Cr2O7, CAS No.: 7778-50-9): with purity>99.99%, or chromium standard solution with certain concentration approved and awarded with reference material certificate by the State.
3.4 Preparation of standard solution
3.4.1 Chromium standard stock solution (1,000 mg/L): accurately weigh 1.4315 g (accurate to 0.0001 g) potassium bichromate, dissolve in water, transfer into 500 mL volumetric flask, dilute to the scale with nitric acid solution (5+95), and mix uniformly.
3.4.2 Chromium standard intermediate solution (1.00 mg/L): pipet 1.00 mL chromium standard stock solution into 1,000 mL volumetric flask, add nitric acid solution (5+95) to the scale and mix uniformly.
3.4.3 Chromium standard series solution: respectively pipet 0 mL, 0.200 mL, 0.400 mL, 2.00 mL, 0.800 mL, 1.20 mL and 1.60 mL chromium standard intermediate solution into 100 mL volumetric flasks, add corresponding food simulants to the scale and mix uniformly. The series concentrations of this standard solution are 0 μg/L, 2.00 μg/L, 4.00 μg/L, 8.00 μg/L, 12.0 μg/L and 16.0 μg/L.
Note: specific concentration of chromium in standard solution series may be determined according to the sensitivity and linear range of instruments and the actual concentration of chromium in the soak solution. If the selected food simulant is neutral or alkaline, then appropriate nitric acid is required to be added to make the concentration of nitric acid in this solution be about 5% (volume fraction).
4 Instruments and Apparatus
Note: all glasswares shall be soaked in nitric acid solution (1+5) overnight, flushed with tap water repeatedly, and finally washed clean with water.
4.1 Graphite furnace atomic absorption spectrometer: equipped with graphite furnace atomizer and chromium hollow cathode lamp.
4.2 Analytical balance: with sensibility of 0.1 mg.
5 Analysis Steps
5.1 Pretreatment of specimen
Carry out migration test according to the intended use and service conditions of to-be-tested sample and the methods and test conditions for migration test in GB 5009.156 and GB 31604.1. After full mixing of soak solution, take some soaked test solution for analysis. If the soaked test solution is neutral or alkaline, add appropriate amount of nitric acid to make the concentration of nitric acid in this test solution be about 5% (volume fraction). Meanwhile, carry out the specimen blank test.
5.2 Determination
5.2.1 Reference condition of instruments
See Table A.1 for reference conditions of instruments.
5.2.2 Plotting of standard curve
Simultaneously inject 10 μL chromium standard series solution and 5 μL ammonium dihydrogen phosphate solution (20 g/L) (optimum injection volume may be determined according to the adopted instrument) into graphite furnace for determination of absorbance, and plot standard curve with standard series concentration as x-axis and corresponding absorbance as y-axis.
5.2.3 Determination of specimen solution
Simultaneously inject 10 μL blank solution, specimen soak solution and 5 μL ammonium dihydrogen phosphate solution (20 g/L) (optimum injection volume may be determined according to the adopted instrument) into graphite furnace, determine their absorbance value after atomization, compare with standard series for quantification.
Contents of GB 31604.25-2016
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
