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This standard replaces GB/T 5009.58-2003 Method for Analysis of Hygienic Standard of Polyethylene Resin for Food Packaging, GB/T 5009.59-2003 Method for Analysis of Hygienic Standard of Polystyrene Resin for Food Packaging, and GB/T 5009.71-2003 Method for Analysis of Hygienic Standard of Polypropylene Resin for Food Packing for the determination of n-hexane extract; as well as GB/T 5009.99-2003 Method for Analysis of Hygienic Standard of Polycarbonate Resin Used as Food Containers and Packaging Materials and GB 13114-1991 Hygienic Standard for Polyethylene Terephthalate Resin Used as Food Containers and Packaging Materials for the determination of extract.
The following changes have been made with respect to GB/T 5009.58-2003, GB/T 5009.59-2003, GB/T 5009.71-2003, GB/T 5009.99-2003 and GB 13114-1991:
——The standard name is revised as " National Food Safety Standard - Food Contact Materials and Articles - Products - Determination of Extract in Resins";
——The scope of the standard is modified;
——Determination methods are modified.
National Food Safety Standard
Food Contact Materials and Articles- Determination of Extract in Resins
1 Scope
This standard specifies methods for determining the extract in resins of food contact materials and their products.
This standard is applicable to the determination of extract in polyethylene, polystyrene, polypropylene, polycarbonate and polyethylene terephthalate resins of food contact materials and their products.
2 Theory
Extract the specimen with extract, evaporate the extract to dryness, dry the residue, and determine the content of extract in the specimen by gravimetric method.
3 Reagents and Materials (Extract)
Unless otherwise specified, analytically pure reagents and Grade 2 water (specified in GB/T 6682) are adopted for the purposes of this method.
3.1 Reagents
3.1.1 Acetic acid (CH3COOH).
3.1.2 Absolute ethanol (C2H5OH).
3.1.3 95% ethanol.
3.1.4 n-hexane (C6H14).
3.1.5 n-heptane (C7H16).
3.2 Preparation of reagents (extract)
3.2.1 4% acetic acid solution (volume fraction): measure 40mL of acetic acid, add 960mL of water, and mix well.
3.2.2 20% ethanol solution (volume fraction): measure 200mL of absolute ethanol, add 800mL of water, and mix well.
3.2.3 65% ethanol solution (volume fraction): measure 650mL of absolute ethanol, add 350mL of water, and mix well.
4 Apparatuses
4.1 Balance: with a sensitivity of 0.1mg.
4.2 Electrothermal constant-temperature dry oven.
4.3 Tweezers.
4.4 Water bath.
5 Analytical Procedures
5.1 Sampling method
Operate according to GB 5009.156.
5.2 Selection of specimen extract and extraction conditions
Operate according to corresponding product standard.
5.3 Determination of specimen
5.3.1 Determination by immersion extraction
Put 2g (to the nearest 0.1mg) of thin film with area of about 6.45cm2 after cutting into a beaker, add 200mL of extract, and put the beaker into 50℃ (to the nearest ±1℃) water bath to heat to 50℃ (to the nearest ±1℃) for the extraction time that is based on corresponding product standard; immediately filter the test solution to a evaporating dish which has reached constant weight by rapid qualitative filter paper while hot, wash the specimen and container with a small amount of 50℃ extract, filter the washing solution and combine it. Evaporate the filtrate to dryness in 70℃~80℃ water bath, put the evaporating dish containing residue into 100℃±2℃ electrothermal constant-temperature dry oven and dry for 2h; after that, take out the evaporating dish, put it into desiccator to cool for 30min, and then weight it. Carry out blank test simultaneously.
5.3.2 Determination by reflux extraction
Put 2g (to the nearest 0.1mg) of thin film with area of about 6.45cm2 after cutting or resin particle into a 500mL full glass distiller flask, add 200mL extract, connect to condenser tube, heat the flask until extract boils slightly for reflux time according to corresponding product standard; immediately filter the extract to a evaporating dish which has reached constant weight with rapid qualitative filter paper while hot, wash the filter apparatus and specimen with a small amount of 50℃ extract, filter the washing solution and combine the filtrate. Evaporate the filtrate to dryness in water bath, put the evaporating dish containing residue into 100℃±2℃ electrothermal constant-temperature dry oven and dry for 2h; after that, take out the evaporating dish, put it into desiccator to cool for 30min, and then weight it. Carry out blank test simultaneously.
Foreword i
1 Scope
2 Theory
3 Reagents and Materials (Extract)
4 Apparatuses
5 Analytical Procedures
6 Expression of Analysis Results
7 Precision
