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This standard replaces the part specifying determination of ignition residue of GB/T 5009.58-2003 Method for Analysis of Hygienic Standard of Polyethylene Resin for Food Packaging.
The following main changes have been made with respect to GB/T 5009.58-2003 (the previous edition):
——This standard is renamed as "National Food Safety Standard - Food Contact Materials and Articles - Determination of Ignition Residue in Resin".
National Food Safety Standard
Food Contact Materials and Articles
Determination of Ignition Residue in Resin
1 Scope
This standard specifies the determination method for ignition residue in resin in food contact materials and articles.
This standard is applicable to determination of ignition residue in polyethylene resin in food contact materials and articles.
2 Principle
The mass of residue of test specimen after it is carbonized and then burned at 800℃.
3 Instruments and Apparatus
3.1 Balance: with sensitivity of 0.1mg.
3.2 High temperature furnace: with maximum service temperature greater than or equal to 900℃.
3.3 Dryer.
3.4 Crucible: silica crucible or porcelain crucible.
4 Analysis Steps
4.1 Sampling method
Operate according to GB 5009.156.
4.2 Specimen determination
Weigh 5g~10g (to the nearest of 0.1mg) of particle specimen and put it into crucible which has been dried to constant mass at 800℃±25℃, carbonize it carefully until there is no smoke, then put it into 800℃±25℃ high temperature furnace and burn it for 2h, cool it down to about 200℃ and take it out, put it in dryer to cool it for 30 min and then weigh it; put it back to high temperature furnace and burn it at 800℃±25℃ for 30 min, cool it down and weigh until the difference between two masses from two adjacent times of weighing does not exceed 2.0mg.
5 Expression of Analysis Results
The content of ignition residue in the specimen shall be calculated according to Formula (1):
(1)
Where,
X——the content of ignition residue in the specimen, g/100g;
m1——the mass of crucible +residue, g;
m2——the mass of the crucible, g;
m3——the mass of the specimen, g;
100——the conversion coefficient.
The calculation result is expressed by the arithmetic average of the results from two independent determinations under repeatability condition, with three significant figures reserved.
6 Accuracy
The absolute difference of the results from two independent determinations under repeatability condition shall not exceed 20% of the arithmetic average.
Foreword i
1 Scope
2 Principle
3 Instruments and Apparatus
4 Analysis Steps
5 Expression of Analysis Results
6 Accuracy
