GB 31604.31-2025

National food safety standard for food contact materials and products - Determination of residual and migration amounts of vinyl chloride, 1,1-dichloroethylene and 1,1-dichloroethane (English Version)

Standard No.

GB 31604.31-2025

Language

Chinese, Available in English version

Release Date

2025

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB 31604.31-2025

Scope

This standard specifies the determination method for the residual and migration amount of vinyl chloride, 1,1-dichloroethylene and 1,1-dichloroethane in food contact materials and their products. This standard is applicable to the determination of the residual and migration amount of vinyl chloride, 1,1-dichloroethylene and 1,1-dichloroethane in plastics, coatings, adhesives, paper and paper products, and inks.

Introduction

Core changes in the standard revision

Comparison dimensions	GB 31604.31-2016	GB 31604.31-2025
Detection target	Only vinyl chloride	Newly added 1,1-dichloroethylene and 1,1-dichloroethane
Detection method	GC-FID single method	GC-ECD (first method) + GC-MS (second method)
Detection limit	0.5 mg/kg	Residue 0.1 mg/kg/Migration 0.001 mg/kg

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Analysis of key technical points of the method

1. Key steps for residue determination

Sample pretreatment should pay attention to: Plastic/paper products need to be broken to ≤0.5cm, and coating materials need to be scraped and ground. When using N,N-dimethylacetamide as a solvent, it must be strictly controlled to be stored at 4℃ away from light, and the standard product must not be reused after opening.

2. Instrument parameter optimization

Chromatographic column	6% cyanophenyl-polymethylsiloxane column (60m×250μm×1.4μm)
Temperature program	35℃(3min)→5℃/min→60℃→30℃/min→255℃(1min)
ECD detector	300℃ tail gas 30mL/min

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Special requirements for migration determination

• Temperature control for different simulants: olive oil 110℃, ethanol 60℃
• Area conversion formula: X₁=(cc₀)×V/S × S₀/m₁
• Sealing products are calculated by piece: X₂=(cc₀)×V/n

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Implementation suggestions

1. Laboratories should establish a dual-platform verification mechanism of GC-ECD and GC-MS
2. For PVC materials, it is necessary to focus on monitoring the residual vinyl chloride monomer
3. During migration tests, an airtight device should be used to prevent volatile losses
4. It is recommended to conduct a solvent blank control for each batch

Technology evolution analysis

This revision will increase the detection sensitivity by 5-50 times through:
1) Detector upgraded to electron capture detector (ECD)
2) Added mass spectrometry confirmation step
3) Optimized headspace equilibrium temperature and time parameters

GB 31604.31-2025 Referenced Document

• GB 5009.156 National Food Safety Standards General Rules for Pretreatment Methods for Migration Tests of Food Contact Materials and Products
• GB/T 6682 Water for analytical laboratory use.Specification and test methods

GB 31604.31-2025 history

• 2025 GB 31604.31-2025 National food safety standard for food contact materials and products - Determination of residual and migration amounts of vinyl chloride, 1,1-dichloroethylene and 1,1-dichloroethane
• 2017 GB 31604.31-2016 National food safety standard Determination of vinyl chloride and migration of food contact materials and products
• 2009 GB/T 23296.13-2009 Food contact materials.Determination of vinyl chloride monomer in plastics.Gas chromatography
• 2003 GB/T 5009.68-2003 Method for analysis of hygienic standard of perchorovinyl-coating for inner wall of food container
• 1996 GB/T 5009.68-1996 Analytical method of hygienic standard for perchlorethylene paint on the inner wall of food containers
• 1994 GB/T 14943-1994 Analysis method for residual 1,1-dichloroethane in polyvinyl chloride resin and molded products used in food containers and packaging materials

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