GB 31604.28-2016National food safety standard - Food contact materials and products - Determination of di (2-ethylhexyl) adipate and migration (English PDF)

3.1 Reagent

Unless otherwise stated, the reagents used in this method shall be analytical

pure. The water shall be the primary water specified in GB/T 6682.

3.1.1 Tetrahydrofuran (C4H8O, CAS No..109-99-9)

3.1.2 Methanol (CH4O,CAS No..67-56-1)

3.1.3 N-hexane (C6H12,CAS No..110-54-3). Chromatographic pure

3.2 Standard product

di (2-ethylhexyl) adipate (C22H42O4, CAS No.. 103-23-1). purity>=99.8%, or a

standard substance certified by the State and granted the standard

The mass spectrum conditions are as follows.

a) Mass spectrum interface temperature. 250°C;

b) Temperature of ion source. 250°C;

c) Ionization mode. EI;

d) Ionization energy. 70 eV;

e) Determination method. select the ion monitoring mode, the monitoring

ion range(m/z) of DEHA. 40~370, the DEHA characteristic ions of are.

129, 147, 112, 71, of which 129 is quantitative ion;

f) Solvent delay by. 5 min.

5.5 Making of standard curve

According to the determination conditions listed in 5.4, inject the standard

working solution (3.3.3) into the gas chromatography-mass spectrometer in

turn. The standard curve was drawn with the concentration of the standard

working solution as the horizontal coordinate with the unit of mg per liter

(mg/L), and the corresponding peak area of DEHA as the vertical coordinate.

See figure A.1. for a standard chromatogram.

5.6 Determination of sample solution

5.6.1 Qualitative determination

In accordance with the determination conditions listed in 5.4, inject the

sample solution (5.2) and the blank solution (5.3) into the gas

chromatography-mass spectrometer for determination. When determine the

sample under the same experimental conditions, if the deviation of the

chromatographic peak retention time of the substance to be determined in the

sample solution is within ±2.5% of the chromatographic peak retention time of

the standard substance; and all the selected ions appear in the sample mass

spectrometry after background subtraction; and the deviation of the relative

abundance of the qualitative ion in the sample spectrum compared with the

relative abundance of the qualitative ion in the standard solution with similar

concentration does not exceed the range specified in Table 1, then it can be

determined that there is such substance in the sample. The characteristic

ions and their abundance ratios of DEHA are shown in Table 2. For DEHA

chromatogram see figure A.2.

Table 1 -- Maximum allowable deviation of relative ion abundance in

qualitative confirmation

Relative ion abundance K /% >50 20~50 10~20 <=10

DEHA concentration of 2mg/mL is obtained. Store the solution in the

refrigerator for validity period of 1 month.

10.4.2 DEHA standard intermediate solution (Water, acidic, alcohol

based food simulants analysis)

Draw 2.5mL DEHA standard reserve solution (10.4.1) with graduated pipette

to 50mL volumetric bottle, dilute to the scale with n-hexane. The standard

intermediate solution of DEHA is obtained with the concentration of

100.0mg/L. The storage method of the solution is the same as that of 10.4.1.

10.4.3 DEHA standard working solution (for water, acidic, alcohol based

food simulants analysis)

Draw with graduated pipette and micro-syringe respectively 50µL, 0.2mL,

0.5mL, 1.0mL, 2.0mL, 5.0mL of the DEHA standard intermediate solution

(10.4.2), place them in 6 10mL volumetric bottles, dilute with n-hexane, meter

the volume and shake to mix well. The standard working solution of DEHA is

obtained with concentration of 0.5mg/L, 2.0mg/L, 5.0mg/L, 10.0mg/L,

20.0mg/L, 50.0mg/L. The storage method is the same as that of 10.4.1.

10.4.4 DEHA standard reserve solution (for oil-based food simulants

analysis)

Weigh DEHA 50mg (precision to 0.0001g) and put it into the 50mL beaker.

Add oil-based food simulant 50g (precision to 0.0001g), dissolve and mix

evenly. The concentration of the standard reserve solution is 1000mg/kg.

Store the solution in the refrigerator for validity period of 1 month.

10.4.5 DEHA standard intermediate solution (for oil-based food

simulants analysis)

Weigh 1.0g (precision to 0.01g) of DEHA standard reserve solution (10.4.4),

put into the 10mL volumetric bottle. Weigh accurately 9.0g (precision to

0.0001g) of oil-based food simulant and put into the same bottle. Mix to obtain

the DEHA standard intermediate solution with the concentration of 100mg/kg.

The storage method of the solution is the same as that of 10.4.4.

10.4.6 DEHA standard working solution (for oil-based food simulants

analysis)

Weigh respectively 0.2g, 0.5g, 1.0g, 2.0g, 4.0g, 5.0g (precision to 0.01g) of

the DEHA standard intermediate solution (10.4.5), place them into 6 10mL

volumetric bottles, add respectively 9.8g, 9.5g, 9.0g, 8.0g, 6.0g, 5.0g

(precision to 0.0001g) of oil-based food simulant, shake to mix and obtain the

standard working solution of DEHA with concentration of 2mg/kg, 5mg/kg,

10mg/kg, 20mg/kg, 40mg/kg, 50mg/kg respectively. Weigh respectively the

e) Determination method. select the ion monitoring mode, the monitoring

ion range(m/z) of DEHA. 40~370, the DEHA characteristic ions of are.

129, 147, 112, 71, of which 129 is the quantitative ion;

f) Solvent delay by. 5 min.

12.5 Making of standard curve

In accordance with the determination conditions listed in 12.4, determine

respectively the water, acid, alcohol, oil-based food simulant standard

working solution (10.4.3, 10.4.6). Draw the standard curve using the DEHA

concentration in the standard working solution as the horizontal coordinate, in

unit of "milligram per liter(mg/L) (water, acid, alcohol-based food simulant), or

milligrams per kilogram (mg/kg) (oil-based food simulant)", and the peak area

of corresponding DEHA as the vertical coordinate.

12.6 Determination of sample solution

12.6.1 Qualitative determination

In accordance with the determination conditions listed in 12.4, inject the

sample solution (12.2) and the blank solution (12.3) into gas chromatography

mass spectrometer for determination. The qualitative method is the same as

5.6.1.

12.6.2 Quantitative determination

When determine the sample and blank solution, deduct the blank value to

obtain the peak area of DEHA.