GB 31604.50-2020National food safety standard - Food contact materials and articles - Determination of nonylphenol migration (English PDF)

3.1 Reagents

3.1.1 Glacial acetic acid (C2H4O2).

(volume fraction) acetic acid solution to set volume to the graduation of scale.

Obtain standard working solutions of which the mass concentrations are 0.01mg/L, 0.02mg/L, 0.03mg/L, 0.05mg/L, 0.10mg/L, 0.20mg/L. Before getting on the machine, it needs to be processed synchronously with the food simulant soaking solution in accordance with 5.1.2.1.

3.4.3.2 Oil-based food simulant standard working solution

Respectively and accurately weigh 5.00g (to the nearest of 0.1mg) of olive oil into 6 stoppered glass centrifuge tubes. Respectively add 0.01mL, 0.02mL, 0.03mL, 0.05mL, 0.10mL, 0.20mL of standard intermediate solution (5mg/L).

Vortex to mix well. Obtain 0.01mg/kg, 0.02mg/kg, 0.03mg/kg, 0.05mg/kg, 0.10mg/kg, 0.20mg/kg standard working solutions. Before getting on the machine, it needs to be processed synchronously with the food simulant soaking solution in accordance with 5.1.2.2.

3.4.3.3 Isooctane standard working solution

Respectively and accurately pipette 0.02mL, 0.04mL, 0.06mL, 0.10mL, 0.20mL, 0.40mL of standard intermediate solution (5mg/L) into six 10mL volumetric flasks. Use isooctane to set volume to the graduation of scale. Mix well. Obtain standard working solutions of which the mass concentrations are 0.01mg/L, 0.02mg/L, 0.03mg/L, 0.05mg/L, 0.10mg/L, 0.20mg/L. Before getting on the machine, it needs to be processed synchronously with the food simulant soaking solution in accordance with 5.1.2.3.

3.4.3.4 Standard working solutions of other food simulants, chemical

alternative solvents Respectively pipette 0.02mL, 0.04mL, 0.06mL, 0.10mL, 0.20mL, 0.40mL of standard intermediate solution (5mg/L) into six 10mL volumetric flasks. Use corresponding food simulants or chemical alternative solvents to set volume to the graduation of scale. Obtain other water-based food simulants or chemical alternative solvent standard working solutions of which the mass concentrations are 0.01mg/L, 0.02mg/L, 0.03mg/L, 0.05mg/L, 0.10mg/L, 0.20mg/L.

4.1 Liquid chromatography tandem triple quadrupole mass spectrometer:

equipped with electrospray ion source (ESI).

4.2 Vortex oscillator.

4.3 Analytical balance: resolutions are 0.0001g, 0.01g.

4.4 High-speed centrifuge: the maximum speed >10000r/min.

5.2 Instrument reference conditions

5.2.1 Liquid chromatography conditions

The reference conditions of liquid chromatography are as follows:

a) Chromatographic column: C18 column, 2.6um, 2.1mmx150mm (or equivalent chromatographic column).

b) Mobile phase: methanol-water (90+10, volume ratio).

c) Flow rate: 0.3mL/min.

d) Column temperature: 40°C.

e) Injection volume: 2uL.

5.2.2 Mass spectrometry conditions

The mass spectrometry reference conditions are as follows:

a) Ionization mode: electrospray ionization negative ion mode (ESI-).

b) Mass spectrometry scan mode: multiple reaction monitoring (MRM).

c) For other mass spectrometer parameters, refer to Table A.1 in Annex A.

5.3 Drawing of standard curve

According to the instrument reference conditions listed in 5.2, determine the standard working solution. Take the concentration of nonylphenol in the standard working solution as the abscissa, the corresponding quantitative ion peak area as the ordinate to draw the standard curve and obtain linear equation.

Refer to Annex B for the chromatogram of the nonylphenol standard working solution.

5.4 Determination of test solution

5.4.1 qualitative determination

According to the instrument reference conditions listed in 5.2, determine the food simulant test solution and standard working solution. If the deviation of the retention time of the mass chromatographic peak of the analyte in the test solution and the standard solution is within +/-2.5%, the signal-to-noise ratio of all qualifier ions exceeds 3:1; the relative abundance of the qualitative ion pair is consistent with the relative abundance of the standard solution of equivalent concentration. When the relative abundance deviation does not exceed the provisions of Table 1, it can be judged that the corresponding analyte exists in and articles to the volume (V) of food or food simulants; the density of various liquid foods is usually calculated as 1kg/L, in square decimeters per kilogram (dm2/kg). When S/V is known in actual use, F is the actual S/V. When S/V cannot be estimated, F uses 6dm2/kg, that is, 6dm2 of food contact materials and articles contact 1kg of food or food simulants.

The result retains at least 2 significant digits.

6.2 Calculation of specific nonylphenol migration for food contact

materials and articles of sealed products (expressed in mg/piece)

When the intended use is unknown, when the specific nonylphenol migration for food contact materials and articels of sealed products is expressed in mg/piece, it is calculated according to formula (2). The migration test method used, the contact area of a single sealed product and the food simulant in the migration test shall be indicated.

Where, X2 - Specific nonylphenol migration, in milligrams per piece (mg/piece);

n - Quantity of sealing products for immersion, in pieces.

The result retains at least 2 significant digits.