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GB 31604.45-2016 English PDF (GB31604.45-2016)

GB 31604.45-2016 English PDF (GB31604.45-2016)

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GB 31604.45-2016: Food contact materials for export -- Polymer materials -- Determination of isocyanates by high performance liquid chromatography

This Standard specifies the determination methods for toluene-2,6-diisocyanate, diphenylmethane-4,4-diisocyanate, toluene-2,4-diisocyanate, naphthalene-1,5- diisocyanate, phenyl isocyanate, hexamethylene diisocyanate and cyclohexyl isocyanate in plastics for food contact material and their products; this Standard specifies the determination method for the total amount of the above 7 isocyanates.
GB 31604.45-2016
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
National Food Safety Standard - Food Contact
Materials and Articles - Determination of Isocyanate
ISSUED ON. OCTOBER 19, 2016
IMPLEMENTED ON. APRIL 19, 2017
Issued by. National Health and Family Planning Commission of the
PEOPLE Republic of China
Table of Contents
Foreword . 3
1 Scope .. 4
2 Principle . 4
3 Reagents and materials . 4
4 Instrument and equipment . 6
5 Analysis steps . 7
6 Expression of the analysis results .. 8
7 Precision . 9
8 Others . 9
6 Expression of the analysis results .. 8
7 Precision . 9
8 Others . 9
Foreword
This Standard replaces GB/T 23296.22-2009 "Food contact materials - Determination of isocyanates in plastics - High performance liquid chromatography" AND SN/T 2741- 2010 "Food contact materials for export - Polymer materials - Determination of isocyanates by high performance liquid chromatography".
Compared with GB/T 23296.22-2009 AND SN/T 2741-2010, main changes of this Standard are as follows.
- Modify the Standard name to "National food safety standard - Food contact materials and articles - Determination of isocyanate";
- Increase the number of analyte to 7;
- Cancel the preparation of blank samples;
- Modify the matrix standard curve to the standard-solution?€?s standard curve; - Modify the expression of the analysis results.
National Food Safety Standard - Food Contact
Materials and Articles - Determination of Isocyanate
1 Scope
This Standard specifies the determination methods for toluene-2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, toluene-2,4-diisocyanate, naphthalene-1,5- diisocyanate, phenyl isocyanate, hexamethylene diisocyanate and cyclohexyl isocyanate in plastics for food contact material and their products; this Standard specifies the determination method for the total amount of the above 7 isocyanates. This Standard applies to the detection of toluene-2,6-diisocyanate, diphenylmethane- 4,4'-diisocyanate, toluene-2,4-diisocyanate, naphthalene-1,5-diisocyanate, phenyl isocyanate, hexamethylene diisocyanate and cyclohexyl isocyanate in polyurethane plastics and their products; this Standard applies to the detection of the total amount of the above 7 isocyanates.
2 Principle
In the sample, after isocyanate is vibrated-extracted by dichloromethane, isocyanate starts derivative reaction with 9-N-methylaminomethyl hydrazine. The derivatized products are separated by C18 liquid chromatography column, determined by fluorescence detector AND quantified by external standard method.
3 Reagents and materials
Unless otherwise specified, all reagents shall be the analytically pure. The water shall be the Grade-1 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Dichloromethane (CH2Cl2). it shall be dried by 5A molecular sieves, stay for overnight for standby application.
3.1.2 Ethyl ether (C2H6O).
3.1.3 Phosphoric acid (HPO3).
3.1.4 Acetonitrile (C2H3N). chromatographic purity.
3.4 Preparation of the standard solution
3.4.1 Isocyanate stock solution (1000 mg/L). weigh and take 0.01 g (accurate to 0.1 mg) of various isocyanate standard materials; dissolve the dichloromethane; then transfer it to a volumetric flask of 10 mL; dilute the dichloromethane to the constant volume. Stock solution shall be stored at -20 ??C under dry preservation; it shall be kept from the light. The term of validity is 1 month.
3.4.2 Standard intermediate-solution of isocyanate (100 mg/L). respectively weigh and take 5mL of dichloromethane in six 10 mL volumetric flasks; respectively transfer them into various 1.0 mL of isocyanate stock solution; dilute them to the constant volume with dichloromethane. The standard intermediate-solution shall be stored at -20 ??C under dry preservation; it shall be kept from the light. The term of validity is 1 month. 3.4.3 Standard working solution of Isocyanate (1 mg/L). respectively weigh and take 5mL of dichloromethane into six 10mL volumetric flasks; respectively add 100 ??L of various standard intermediate-solutions of isocyanate; dilute them to the constant volume with dichloromethane; mix them evenly. Standard working solution shall be stored at -20 ??C under dry preservation; it shall be kept from the light. The term of validity is 2 weeks.
3.4.4 Standard working solution of mixed isocyanate. respectively weigh and take 5 mL of dichloromethane into six 10 mL volumetric flasks; successively add 0.00 mL, 0.01 mL, 0.05 mL, 0.10 mL, 0.25 mL and 0.50 mL of various standard intermediate- solutions of isocyanate; dilute them to the constant volume with dichloromethane; mix them evenly; the mixed standard working solutions whose isocyanate?€?s concentration are respectively 0 mg/L, 0.10 mg/L, 0.50 mg/L, 1.0 mg/L, 2.5 mg/L and 5.0 mg/L can be acquired. These mixed standard working solutions shall be stored at -20 ??C under dry preservation; they shall be kept from the light. The term of validity is 2 weeks. 4 Instrument and equipment
4.1 Liquid chromatograph. configure the fluorescence detector.
4.2 Glass bottle. 20 mL, with PTFE cap; it should be dried before use.
4.3 Aqueous filter membrane. 0.45 ??m.
4.4 pH meter.
4.5 Analytical balance. the sensitivity shall be 0.0001 g and 0.01 g.

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