GB 31604.14-2016National food safety standard - Food contact materials and articles - Determination of migration of 1-octene and tetrahydrofuran (English PDF)

3.1 Reagents

3.1.1 N,N-Dimethylacetamide (DMAC, C4H9NO). of purity > 99.0%.

3.1.2 Water-based, acidic, alcoholic and oil-based food simulants. the reagents used

are as specified in GB 31604.1.

3.2 Reagent preparation

3.2.1 Water-based, acidic, alcoholic and oil-based food simulants. the operation is as

specified in GB 5009.156.

3.3 Standard substances

3.4.6 Isooctane internal standard intermediate solution (120 µg/mL). transfer 3.0 mL

of isooctane internal standard stock solution to a 50 mL volumetric flask and use DMAC

to add to scale. The storage conditions are the same as those specified in 3.4.1.

3.4.7 Water-based, acidic and alcoholic THF standard stock solution (2.2 mg/mL).

measure 99 mL of water to pour into a 100 mL volumetric flask and weigh with the

stopper (accurate to 0.000 1 g). Add 220 mg of THF, about 250 µL; weigh once again

(accurate to 0.000 1 g); and use water to add to scale. Calculate the concentration of

THF accurately. Store in a dark place at 4°C, with a period of validity of one week.

3.4.8 Water-based, acidic and alcoholic THF standard intermediate solution (22

µg/mL). measure 90 mL of water to pour into a 100 mL volumetric flask; transfer 1.0

mL of water-based THF standard stock solution; and use water to add to scale. The

storage conditions are the same as those specified in 3.4.7.

3.4.9 Water-based, acidic based and alcoholic food simulant medium standard

working solution of THF. measure respectively 45 mL of water-based, acidic and

alcoholic food simulants to pour into six 50 mL volumetric flasks. Add a certain volume

of water-based, acidic and alcoholic THF standard intermediate solution in accordance

with Table A.2 and use corresponding food simulants to add to scale.

Accurately transfer 10.0 mL of the above-mentioned solutions to six headspace bottles

respectively and immediately seal using insulator and aluminium cover. Use a micro-

syringe to transfer 100 µL of water-based, acidic and alcoholic THP internal standard

intermediate solution to all headspace bottles through the insulator, and mix up.

3.4.10 Water-based, acidic based and alcoholic THP internal standard stock solution

(1 mg/mL). weigh 99 mL of water to pour into a 100 mL volumetric flask; weigh with the

stopper (accurate to 0.000 1 g); add 100 mg of THP, about 150 µL; weigh once again

(accurate to 0.000 1 g); and use water to add to scale. Accurately calculate the

concentration of THP. The storage conditions are the same as those specified in 3.4.7.

3.4.11 Water-based, acidic based and alcoholic THP internal standard intermediate

solution (70 µg/mL). measure 90 mL of water to pour into a 100 mL volumetric flask;

transfer 7.0 mL of water-based THP internal standard stock solution; and use water to

add to scale. The storage conditions are the same as those specified in 3.4.7.

3.4.12 Oil-based THF standard stock solution (1.0 mg/mL). measure 45 mL of DMAC

to pour into a 50 mL volumetric flask and weigh with the stopper (accurate to 0.000 1

g). Then add 50 mg of THF, about 60 µL; weigh once again (accurate to 0.000 1 g);

and use DMAC to add to scale. Accurately calculate the concentration of THF. The

storage conditions are the same as those specified in 3.4.7.

3.4.13 Oil-based THF standard intermediate solution (50 µg/mL). transfer 1.0 mL of

oil-based THF standard stock solution to a 20 mL volumetric flask and use DMAC to

add to scale. The storage conditions are the same as those specified in 3.4.7.

In accordance with the requirements of GB 5009.156 and GB 31604.1, carry out

migration test for sample and obtain food simulant test solutions. If a food simulant test

solution obtained is not ready for further test at once, it shall be stored in a refrigerator

at 0°C~4°C, which shall be kept out of the sun.

Cool or restore the food simulant test solutions to room temperature for further test.

5.2 Test solution preparation

5.2.1 Preparation of water-based, acidic and alcoholic food simulant test

solutions for the determination of 1-octylene

Transfer 1.0 mL of water-based food simulant from the migration test to a headspace

bottle, and immediately seal using insulator and aluminium cover. Use a micro-syringe

to add in turn 200 µL of isooctane internal standard intermediate solution and 200 µL

of DMAC through the insulator; and mix up.

5.2.2 Preparation of olive oil medium food simulant test solution for the

determination of 1-octylene

Weigh 1 g (accurate to 0.01 g) of olive oil medium food simulant from the migration

test to place in a headspace bottle; and hereafter, process in accordance with the

operating procedures of 5.2.1 "and immediately seal using insulator and aluminium

cover .".

5.2.3 Preparation of water-based, acidic and alcoholic food simulant test

solution for the determination of tetrahydrofuran

Transfer 10.0 mL of water-based, acidic and alcoholic food simulant test solution from

the migration test to a headspace bottle, and immediately seal using insulator and

aluminium cover. Use a micro-syringe to add 100 µL of water-based, acidic and

alcoholic THP internal standard intermediate solution through the insulator; and mix

up.

5.2.4 Preparation of olive oil medium food simulant test solutions for the

determination of tetrahydrofuran

Weigh 10 g (accurate to 0.01 g) of olive oil medium food simulant from the migration

test to place into a headspace bottle, and immediately seal using insulator and

aluminium cover. Use a micro-syringe to add 100 µL of oil-based THP internal standard

intermediate solution (3.4.16) through the insulator; then use a micro-syringe to add

rapidly 300 µL of DMAC; and mix up.

5.3 Preparation of blank test solutions

Process the food simulants in accordance with the procedures specified in 5.2, which

are not in contact with food contact materials.

5.4 Determination

f) sampling method. split stream sampling with a split ratio of 10.1;

g) sample volume. 250 µL;

h) transmission line temperature. 250°C;

i) ionization mode. EI;

j) solvent delay. 2.2 min;

k) mass spectrum scanning method. selected ion mode (SIM), turning off filament

after 8 min;

l) isooctane. quantitative ion m/z 57, qualitative ions m/z 58 and 99; 1-octene.

quantitative ion m/z 70, qualitative ions m/z 83 and 112; tetrahydrofuran.

quantitative ion m/z 72, qualitative ions m/z 71 and 73; tetrahydropyrane.

quantitative ion m/z 85, qualitative ions m/z 67 and 86.

12.4.2 Plotting of standard working curves

Carry out determination of standard working solutions in turn in accordance with the

determination conditions listed in 12.4.1. Plot standard working curves using the 1-

octene or tetrahydrofuran concentrations in standard working solutions as the abscissa,

in mg/L or mg/kg, and the peak area ratio of 1-octene/isooctane or

tetrahydrofuran/tetrahydropyrane as the ordinate. For the total ion current

chromatogram of gas chromatography-mass spectrometry refer to Annex B.

12.4.3 Confirmation

Take test solutions (12.2) to carry out the confirmatory test of the internal standard

method in accordance with the gas chromatographic-mass spectrome...

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