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This standard replaces GB 31604.8-2016 National food safety standard - Food contact materials and articles - Determination of overall migration.
The following main changes have been made with respect to GB 31604.8-2016:
——the application scope is modified;
——the requirements of precision are modified;
——"Part II Determination of overall migration in olive oil" is added.
National food safety standard
Food contact materials and articles - Determination of overall migration
1 Scope
This standard specifies the determination method of overall migration of food contact materials and articles.
This standard is applicable to the determination of overall migration of food contact materials and articles.
Part I Determination of overall migration in water-based food simulants and chemical alternative solvents
2 Principle
Take water-based food simulants and chemical alternative solvents [such as n-hexane, isooctane, 95% (volume fraction) ethanol solution and n-heptane] to carry out migration test of specimen under the selected conditions. After the soaking solution obtained from the migration test is evaporated and dried, deduct the corresponding blank to obtain the total amount of all non-volatile substances that the specimen migrates to the water-based food simulants and chemical alternative solvents.
3 Reagents and materials
Unless otherwise specified, analytically-pure reagents and Grade II water specified in GB/T 6682 are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Anhydrous ethanol (C2H6O).
3.1.2 Acetic acid (C2H4O2).
3.1.3 Chloroform (CHCl3).
3.1.4 n-hexane (C6H14).
3.1.5 Isooctane (C8H18).
3.1.6 95% ethanol.
3.1.7 n-heptane (C7H16).
3.2 Preparation of reagents
Preparation of water-based food simulants: 4% (volume fraction) acetic acid solution, 10% (volume fraction) ethanol solution, 20% (volume fraction) ethanol solution and 50% (volume fraction) ethanol solution corresponding to water-based food or alcoholic beverage in GB 31604.1 are prepared according to GB 5009.156.
3.3 Materials
3.3.1 Evaporating dish: glass or ceramic, 50~250mL.
3.3.2 Glass dryer: equipped with desiccant such as silica gel or anhydrous calcium chloride.
3.3.3 Filter paper: qualitative filter paper, rapid.
3.3.4 Lint-free clean paper.
4 Apparatus
4.1 Balance: with a sensitivity of 0.1mg.
4.2 Electric thermostatic drying oven.
4.3 Electro-thermostatic water bath or other electric heating equipment.
5 Analytical procedures
5.1 Migration test
Food contact materials and articles are subjected to migration test according to the requirements of GB 31604.1 and GB 5009.156.
5.2 Determination of overall migration in water-based food simulants and chemical alternative solvents
Prior to use, wash and drain the evaporating dish, dry it for 2h in an electric thermostatic drying oven at 100±5℃, then cool it in a dryer for 0.5h and weigh it, repeat drying, cooling and weighing until it reaches a constant weight (that is, the difference between the two weights is not greater than 0.5mg), and the mass in the last weighing is the mass of the empty evaporating dish.
Take an empty evaporating dish with constant weight, add 200mL soaking solution obtained from the migration test (if the specification of the evaporating dish is less than 200mL, the drying shall be carried out by several times), put it in a water bath which is not higher than 10℃ than the boiling point temperature of soaking solution for evaporation, suck the water droplets on the bottom of evaporating dish with filter paper or lint-free clean paper (no paper fibers shall be left on the bottom of evaporating dish), put the evaporating dish in an electric thermostatic drying oven at 100±5℃ for drying for 2h, then take it out, weigh it after cooling for 0.5h in a dryer, repeat drying, cooling and weighing until it reaches a constant weight, and the mass in the last weighing is the mass of the evaporating dish with specimen residue after evaporation. The mass of the soaking solution residue for specimen determination is the mass of the evaporating dish with specimen residue after evaporation minus the mass of empty evaporating dish.
5.3 Determination of chloroform extract
The determination procedures are applicable to food contact materials and articles that require detection of chloroform extract as stipulated in product standards.
Add 20mL chloroform to the residue obtained in 5.2, wet the residue, filter it with filter paper, collect the filter liquor into an evaporating dish with constant weight, and then extract the residue twice with 20mL chloroform respectively. Then wash the filter paper with a little chloroform, put the filter liquor into the evaporating dish, and evaporate to dryness according to 5.2, so as to obtain the mass of residue extracted with chloroform from the soaking solution for specimen determination.
5.4 Blank test
Treat the water-based food simulants, chemical alternative solvents and chloroform which are not in contact with food contact materials and articles according to 5.1, 5.2 and 5.3 to obtain the residue mass of blank soaking solution and the residue mass of blank soaking solution extracted with chloroform.
6 Expression of analysis results
6.1 Calculation of overall migration
6.1.1 Expressed in mg/dm2
6.1.1.1 Non-sealed food contact materials and articles
For food contact materials and articles other than sealed articles (such as lids, gaskets and connectors, hereinafter referred to as sealed articles), the overall migration is calculated using Equation (1) when it is expressed in mg/dm2.
(1)
Where,
X1——the overall migration of non-sealed food contact materials and articles, mg/dm2;
m1——the residue mass of soaking solution for specimen determination, mg;
m2——the residue mass of blank soaking solution, mg;
V——the total volume of the specimen soaking solution obtained in migration test, mL;
V1——the volume of soaking solution for determination, mL;
S——the contact area between specimen and soaking solution, dm2.
6.1.1.2 Sealed food contact materials and articles
The overall migration of sealed food contact materials and articles is calculated using Equation (2) when it is expressed in mg/dm2.
(2)
Where,
X2——the overall migration of sealed food contact materials and articles, mg/dm2;
m1——the residue mass of soaking solution for specimen determination, mg;
m2——the residue mass of blank soaking solution, mg;
V——the total volume of the specimen soaking solution obtained in migration test, mL;
V1——the volume of soaking solution for determination, mL;
S——the contact area between specimen and soaking solution, dm2;
S0——the contact area between sealed articles and food in actual use, dm2;
S3——the contact area between the actual container of sealed articles and food, dm2.
6.1.2 Expressed in mg/kg
6.1.2.1 Non-sealed food contact materials and articles
The overall migration of non-sealed food contact materials and articles is calculated using Equation (3) when it is expressed in mg/kg.
X3=X1×F (3)
Where,
X3——the overall migration of non-sealed food contact materials and articles, mg/kg;
X1——the overall migration of non-sealed food contact materials and articles, mg/dm2;
F——the ratio (S/V) of the actual contact area between food contact materials and articles and food to the food mass in the foreseeable use, dm2/kg; the volume of various liquid foods is converted into the corresponding mass according to a density of 1kg/L. When the actual S/V is known, F is the maximum S/V in the foreseeable use; otherwise, F=6dm2/kg, i.e. 6dm2 food contact materials and articles is in contact with 1kg food.
6.1.2.2 Sealed food contact materials and articles
The overall migration of sealed food contact materials and articles is calculated using Equation (4) when it is expressed in mg/kg.
(4)
Where,
X4——the overall migration of sealed food contact materials and articles, mg/kg;
m1——the residue mass of soaking solution for specimen determination, mg;
m2——the residue mass of blank soaking solution, mg;
V——the total volume of the specimen soaking solution obtained in migration test, mL;
V1——the volume of soaking solution for determination, mL;
S——the contact area between specimen and soaking solution, dm2;
S0——the contact area between sealed articles and food in actual use, dm2;
V3——the mass of food in the actual containers of sealed articles, kg; the volume of various liquid foods is converted into the corresponding mass according to a density of 1kg/L.
6.1.3 Expressed in mg/piece
The overall migration of sealed articles is calculated using Equation (5) when it is expressed in mg/piece; the migration test method adopted and the contact area between a single sealed article and food simulant in migration test shall be indicated.
(5)
Where,
X5——the overall migration of specimen, mg/piece;
m1——the residue mass of soaking solution for specimen determination, mg;
m2——the residue mass of blank soaking solution, mg;
V——the total volume of the specimen soaking solution obtained in migration test, mL;
V1——the volume of soaking solution for determination, mL;
n——the number of sealed articles for soaking, piece.
Foreword i
1 Scope
2 Principle
3 Reagents and materials
4 Apparatus
5 Analytical procedures
6 Expression of analysis results
7 Precision
8 Principle
9 Reagents and materials
10 Apparatus
11 Analytical procedures
12 Expression of analysis results
13 Precision
Annex A Suitability judgment
Annex B Confirmation of moisture-sensitive specimens and control of moisture content - Vacuum drying method
Annex C Confirmation of moisture-sensitive specimens and control of moisture content - Constant humidity method
Annex D Typical chromatogram
