Detail of GB 31604.56-2023

Introduction of GB 31604.56-2023

National food safety standard Food contact materials and articles Determination of migration amount of laurolactam 1 Scope This standard specifies the determination method for migration amount of laurolactam in food contact materials and articles. This standard is applicable to the determination of migration amount of laurolactam in polyamide food contact materials and articles. Method I Liquid chromatography 2 Principle The food contact materials and articles are tested using liquid chromatography after being subjected to the migration test. For the aqueous, acidic, and ethanol-containing food simulants and the chemical substitute solvent [95% (v/v) ethanol], the sample is filtered and injected directly; for the oily food simulants, the sample is filtered and injected after liquid-liquid and solid-phase extraction; for the chemical substitute solvent (isooctane), the sample is filtered and injected after removal of the solvent and re-solubilization of the solution with acetonitrile. Perform the qualification as per retention time and the quantification as per external standard method. 3 Reagents and materials Unless otherwise specified, analytically pure reagents, and Class-I water as defined in GB/T 6682, are used for the purpose of this method. 3.1 Reagents 3.1.1 For the acidic, ethanol-containing, and oily food simulants and the chemical substitute solvents: The reagents used shall meet the requirements of GB 5009.156. 3.1.2 Acetonitrile (C2H3N): Chromatographically pure. 3.1.3 Methanoic acid (CH2O2): Chromatographically pure. 3.1.4 Ammonia water: With a mass fraction of ammonia as 25%~28%. 3.1.5 Anhydrous ethanol (C2H6O). 3.2 Reagent preparation 3.2.1 Methanoic acid - water solution: Measure out 5.0mL of methanoic acid and 95mL of water, and mix them well. 3.2.2 Ammonia water - acetonitrile solution: Measure out 2.0mL of ammonia water, 8.0mL of water and 90mL of acetonitrile, and mix them well. 3.2.3 Methanoic acid - acetonitrile - water solution: Measure out 20mL of acetonitrile and 80mL of water, pipette out 100μL of methanoic acid, and mix them well. 3.3 Standard substance The laurolactam standard substance (C12H23NO, CAS No.: 947-04-6, also known as laurel lactam or azacyclotridecan-2-one): With a purity ≥98%, or a standard substance certified by the state and granted a standard substance certificate. 3.4 Preparation of standard solutions

Contents of GB 31604.56-2023

1 Scope 2 Principle 3 Reagents and materials 4 Apparatus 5 Analytical procedures 6 Expression of analysis results 7 Precision 8 Others 9 Principle 10 Reagents and materials 11 Apparatus 12 Analytical procedures 13 Expression of analysis results 14 Precision 15 Others Annex A Chromatograms for the laurolactam standard solutions