GB/T 40031-2021Determination of polychlorinated naphthalenes in electrical and electronic products—Gas chromatorgaphy-mass spectrometry method (English PDF)

7.1 Extraction

7.1.1 Soxhlet extraction device (see 5.2) shall be cleaned with toluene (see 4.1) before use. If necessary, use toluene (see 4.1) for pre-extraction to clean the system.

7.1.2 Accurately weigh 0.1g~0.5g of sample (to the nearest of 0.1mg). Place in the extraction sleeve. The sleeve mouth can be covered with glass wool. Add about 60mL of toluene (see 4.1) to the matching flask (see 5.2). Install the Soxhlet extraction device (see 5.2). Heat for extraction. Each cycle is about 2min~3min. Extract at least 2h. After extraction, after the extract is cooled to room temperature, transfer to a 100mL volumetric flask. Use toluene (see 4.1) to set the volume to the scale. If there are too many impurities in the extract, the extract can be concentrated to 2mL~3mL with a rotary evaporator (see 5.3).

Then transfer to a silica gel solid phase extraction cartridge (see 4.5). Use 30mL of toluene (see 4.1) to rinse the cartridge 5-6 times. Combine the eluates and transfer them to a 100mL volumetric flask. Use toluene (see 4.1) to set volume to the scale.

NOTE: For samples that are soluble in toluene, it may select other Soxhlet extraction organic solvent systems that can dissolve polychlorinated naphthalene and do not dissolve the sample.

7.2 Test

7.2.1 Working conditions of gas chromatography-mass spectrometer

The test result depends on the instrument used. It is impossible to give general parameters for gas chromatography-mass spectrometry analysis. The set parameters shall ensure that the measured component and other components can be effectively separated during chromatographic analysis. The following parameters prove to be feasible for the test:

a) Capillary column: stationary phase 5% phenyl-polymethylsiloxane

7.2.4 Blank test

Conduct the blank test with the specimen.

8.1 Calculation of single polychlorinated naphthalene content in sample

Calculate the content of single polychlorinated naphthalene in the sample according to formula (1):

Where, Xi - The content of single polychlorinated naphthalene in the sample, in milligrams per kilogram (mg/kg);

Ci1 - The mass concentration of the sample solution calculated from the calibration curve, in micrograms per liter (µg/L);

Ci0 - The mass concentration of the blank solution calculated from the calibration curve, in micrograms per liter (µg/L);

V - The final constant volume set of sample solution, in milliliters (mL);

N - The dilution factor of sample solution;

m - The sample mass, in grams (g).

8.2 Calculation of the total polychlorinated naphthalene content in sample

Calculate the content of total polychlorinated naphthalene in the sample according to formula (2): […]