Detail of GB 31604.60-2024

Introduction of GB 31604.60-2024

GB 31604.60-2024 National food safety standard - Food contact materials and articles - Determination of residual solvent content 1 Scope This standard specifies the gas chromatography and the gas chromatography-mass spectrography for the determination of the content of any of the following 25 residual solvents (cyclohexane, methylcyclohexane, acetone, ethyl acetate, methanol, isopropyl acetate, butanone, isopropanol, ethanol, n-propyl acetate, 4-methyl-2-pentanone, n-propanol, butyl acetate, isobutanol, n-butanol, ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol ethyl ether, benzene, ethylbenzene, o-xylene, p-xylene and m-xylene) in food contact composite materials and articles. This standard is applicable to the determination of residual solvent content in composite food contact materials and articles. Method I Gas chromatography 2 Principle Place specimens of food contact materials and articles in headspace bottles, heat them to make the components to be tested reach liquid-gas balance. When the headspace gases are separated by gas chromatographic columns, test the specimens by a hydrogen flame ionization detector and quantify them using the external standard method. 3 Reagents and materials 3.1 Reagents N, N-dimethylformamide (C3H7NO): chromatographically pure. 3.2 Standards Cyclohexane, methylcyclohexane, acetone, ethyl acetate, methanol, isopropyl acetate, butanone, isopropanol, ethyl alcohol, n-propyl acetate, 4-methyl-2-pentanone, n-propyl alcohol, butyl acetate, isobutanol, n-butanol, ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol monoethyl ether, benzene, ethylbenzene, o-xylene, p-xylene and m-xylene: with purity ≥98%; or standard substance certified by the state and granted with standard substance certificate. See Table A.1of Annex A for details. 3.3 Preparation of standard solutions 3.3.1 Single standard substance stock solution (200g/L): accurately weigh 2g (with an accuracy of 0.1mg) of a single standard, dissolve with N, N-dimethylformamide and dilute to 10mL, and mix the solution well. Transfer the obtained solution to a brown glass vessel and store it at -18℃ away from light, with a validity period of six months. 3.3.2 Mixed intermediate standard solutions of non-benzene solvents (10g/L): pipette 2.50mL of single standard substance stock solution (200g/L) of various non-benzene solvents into a 50mL volumetric flask, add N, N-dimethylformamide to the scale, mix the solution well. Transfer the obtained solution to a brown glass vessel and store it at -18℃ away from light, with a validity period of six months. 3.3.3 Mixed intermediate standard solution of non-benzene solvents (10g/L): pipette 2.50mL of single standard substance stock solution (200g/L) of various benzene solvents into a 50mL volumetric flask, add N, N-dimethylformamide to the scale, mix the solution well. Transfer the obtained solution to a brown glass vessel and store it at -18℃ away from light, with an effective period of six months. 3.3.4 Mixed standard intermediate solution (5,000mg/L for non-benzene solvent and 2,500mg/L for benzene solvent): pipette 25.00mL of mixed non-benzene standard intermediate solution (10g/L) and 12.50mL of mixed benzene standard intermediate solution (10g/L) into a 50mL volumetric flask, dilute with N, N-dimethylformamide to the scale, mix well, and transfer the solution to a brown glass vessel. The mass concentrations of non-benzene solvents and benzene solvents in the obtained mixed standard intermediate solution shall be 5,000mg/L and 2,500mg/L, respectively. Store the solution at -18℃ away from light, with a validity period of six months. 3.3.5 Mixed standard series intermediate solutions: pipette 0.20mL, 0.40mL, 1.0mL, 2.0mL, 5.0mL and 10.0mL of mixed standard intermediate solutions (5,000mg/L for non-benzene solvent and 2,500mg/L for benzene solvent) respectively into six 10mL volumetric flasks, dilute with N, N-dimethylformamide to the scale, mix well, and obtain six mixed standard intermediate solutions. The mass concentration of each non-benzene solvent in the mixed standard series intermediate solutions is 100mg/L, 200mg/L, 500mg/L, 1,000mg/L, 2,500mg/L and 5,000mg/L respectively, and that of each benzene solvent is 50mg/L, 100mg/L, 250mg/L, 500mg/L, 1,250mg/L and 2,500mg/L respectively. The solution shall be prepared freshly before use.

Contents of GB 31604.60-2024

1 Scope 2 Principle 3 Reagents and materials 4 Instruments and apparatus 5 Analytical procedure 6 Expression of analysis results 7 Precision 8 Others 9 Principle 10 Reagents and materials 11 Instruments and apparatus 12 Analytical procedure 13 Expression of analysis results 14 Precision 15 Others Annex A Basic information for solvent standards Annex B Chromatogram for mixed standard working solution Annex C Solvent quantitative and qualitative ion table