GB 5009.262-2016Method for analysis of hygienic standard of edible oils (English PDF)

2.1 Matrix vegetable oil

Refined vegetable oil obtained through the refining processes including colour and

odour removal, or vegetable oil produced by ultrasonic degassing at room temperature,

of the same species as that of specimen to be tested. The solvent residual in matrix

vegetable oil shall be lower than the detection limit.

4.1 Reagents

4.2 Preparation of reagent

n-heptane standard working solution. add 1 mL of n-heptane accurately in a 10-mL

volumetric flask immediately; add quickly N,N-dimethylacetamide; add dropwise to the

scale.

4.3 Standard product

Solvent residual standard product. "no. 6 solvent" solution of concentration 10 mg/mL;

the solvent is N,N-dimethylacetamide. Or other standard products for the

determination of solvent residual, which have been certified by the state or granted

standard product certificates.

4.4 Preparation of standard solution

4.4.1 For vegetable oils, weigh 6 shares of 5.0 g (accurate to 0.01 g) of matrix

vegetable oil to place into a 20-mL headspace specimen bottle.

4.4.2 For meals, weigh 6 shares of 3.0 g (accurate to 0.01 g) of matrix meal to place

into a 20-mL headspace specimen bottle; add 400 µL of water to each headspace

specimen bottle; finally use microsyringe to add quickly 0 µL, 3 µL, 9 µL, 15 µL, 30 µL

and 150 µL of no. 6 solvent standard product; after sealing, obtain the matrix meal

standard solutions of concentrations 0 mg/kg, 10 mg/kg, 30 mg/kg, 50 mg/kg, 100

mg/kg and 500 mg/kg.

5.1 Gas chromatograph. equipped with flame ionization detector.

5.2 Headspace bottle. 20 mL, equipped with aluminium cover and sealing washer of

butyl rubber or silicon resin containing no residual of hydrocarbon solutions.

5.5 Ultrasonic oscillator.

5.6 Air blowing oven.

5.7 Thermostatic oscillator.

6.1 Specimen preparation

6.1.1 Preparation of vegetable oil specimen. weigh 5 g (accurate to 0.01 g) of

vegetable oil specimen to place into a 20-mL headspace specimen bottle; add quickly

6.2 Instrument reference conditions

6.2.1 Headspace specimen injector reference conditions

The reference conditions for headspace specimen injector are as follows.

6.2.2 Gas chromatography reference conditions

The reference conditions for gas chromatography are as follows.

6.3 Plotting of standard curves

6.3.1 For vegetable oils, the internal standard method is used in this method for

quantitation.

6.4 Specimen determination

After analyzing the prepared vegetable oil or meal specimen, measure its peak area

and calculate the solvent residual in specimen in accordance with relevant standard

curves.