SN/T 5259-2020Determination of UV-320, UV-327, UV-328 and UV-350 ultraviolet absorbers in coatings gas chromatography-mass spectrometry (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2020.

This standard was proposed and managed by the General Administration of Customs of the People's Republic of China.

Drafting organization of this standard. Guangzhou Customs of the People's Republic of China.

1 Scope

This standard specifies the content of UV-320, UV-327, UV-328 and UV-350 ultraviolet absorbers in water-based paints and solvent-based paints the gas chromatography-mass spectrometry detection method.

This standard applies to the content of UV-320, UV-327, UV-328 and UV-350 ultraviolet absorbers in water-based paints and solvent-based paints the determination.

2 Method summary

The sample is leveled on a clean glass sheet, and after natural air drying, the solvent-based paint is ultrasonically extracted with n-hexane, and the water-based paint is ultrasonically extracted with acetonitrile.

Sound extraction. After the extract is concentrated, it is purified by a solid phase extraction column, filtered by a filter membrane, and measured with a gas chromatography-mass spectrometer. External standard Method quantitative.

3 Reagents and materials

Unless otherwise stated, all reagents are chromatographically pure.

3.1 Methanol.

3.2 n-hexane.

3.3 Acetonitrile.

3.8 Single standard stock solution of ultraviolet absorber. accurately weigh the appropriate amount of UV-320 standard material (3.4), UV-327 standard material (3.5), UV-328 standard material (3.6) and UV-350 standard material (3.7), respectively use methanol (3.1) to make a constant volume, and prepare a concentration of 1 000 mg/L Single-label stock solution.

3.9 UV absorber mixed standard stock solution. accurately pipette 1 mL of the above 4 single standard stock solutions (3.8) to 10 mL volume in the bottle (4.7), use methanol (3.1) to make a constant volume and prepare a UV absorber mixed standard stock solution with a concentration of 100 mg/L.

3.10 Mixed standard working solution. accurately pipette 0.05 mL, 0.1 mL, 0.2 mL, 0.5 mL, 1 mL, 2 mL, 5 mL of the above mixture the standard stock solution (3.9) is placed in 7 10 mL volumetric flasks (4.7), and the volume is fixed with methanol (3.1), and the concentration is 0.5 mg/L, 1 Mixed standard working solutions of mg/L, 2 mg/L, 5 mg/L, 10 mg/L, 20 mg/L, 50 mg/L.

3.11 Silica gel cartridge (6 mL, 1 g). activate with 6 mL methanol (3.1) before use and keep it wet.

3.12 Microporous membrane. 0.2 µm pore size, organic type.

4 Instruments and equipment

4.1 Gas Chromatography Mass Spectrometer. Equipped with EI source.

4.2 Analytical balance. Sensitivity 0.1 mg.

4.3 Ultrasonic generator.

4.4 Rotary evaporator.

4.5 Pipette. 0 mL ~ 10 mL.

4.6 Conical flask with stopper. 50 mL.

4.7 Volumetric flask. 10 mL.

4.8 Round bottom flask. 50 mL.

4.9 Glass sheet. 10 cm×20 cm.

5 Sample preparation

Stir the sample evenly and level it on a clean glass sheet (4.9) to form a thin film of appropriate thickness. Dry naturally in a ventilated place, and wait After it is completely dry, scrape it off with a razor blade, cut into pieces and mix well.

6 Handling of samples

7 Determination

8 Calculation results

The content of various ultraviolet absorbers in the sample is calculated according to formula (1).

9 Lower limit of determination

The lower limit of the four ultraviolet absorbers in this method is 10 mg/kg.

10 Precision

The repeatability and reproducibility of the method are shown in Table 1 and Table 2.