GB/T 41071-2021Determination of polycyclic aromatic hydrocarbons in dye products (English PDF)

7.1 Polycyclic aromatic hydrocarbon single standard stock solutions

Respectively weigh 10 mg of the standard substances listed in Appendix A, and the weights shall be accurate to 0.01 mg; dissolve with n-hexane and dilute to the mark in […]

8.2 Concentrating and solvent replacement

Adopt the nitrogen blowing concentrating method, and the temperature of the nitrogen blowing concentrator shall be set to 30 °C; concentrate the extract (8.1) to 1 mL~2 mL with a small flow rate of nitrogen, wash the wall of the concentrating tube with about 5 mL~10 mL of n-hexane, and then concentrate the liquid to about 1 mL. Purify it later.

8.3 Purification

Fix the Florisil column on the solid-phase extraction device, rinse and purify the column with 4 mL of acetone, and then add 4 mL of n-hexane. After the column is filled, close the control valve and soak for 5 min; then, slowly open the control valve, and close the control valve before the filler is exposed to air. Transfer the concentrated solution (8.2) to the column, wash the concentrating tube several times with about 2 mL of n-hexane in total, and transfer all the washing liquor to the column. Slowly open the control valve and collect the effluent. Before the adsorbent is exposed to air, add about 8 mL of n-hexane-dichloromethane mixed solvent (5.6) for elution, and collect all the eluent.

8.4 Concentrating and making the volume up to mark

The purified eluent shall be concentrated by nitrogen blowing, made up to 1.0 mL with n-hexane, mixed well, and transferred to a sample bottle for analysis later.

8.5 Preparation of blank samples

Prepare blank samples following the same procedures as for sample solution preparation.

9.1 Chromatographic analysis conditions

Since the test results depend on the instrument used, it is impossible to offer general parameters for chromatographic analysis. The use of the parameters in Table 1 has been proved suitable for testing. The optimal analysis conditions can be selected according to different instruments and equipment.

11.1 Detection limit

If Method One in Chapter 8 is used for the preparation of the sample solution, the method detection limit of 18 types of polycyclic aromatic hydrocarbons is 0.2 mg/kg;

If Method Two is used for the preparation of the sample solution, the method detection limit is 1.0 mg/kg.

11.2 Precision

In the same laboratory, the same operator uses the same equipment to carry out independent tests on the same test object within a short period of time according to the same determination method; the absolute difference between two independent test results shall not be greater than 20% of the arithmetic mean of the two determination results.

11.3 Accuracy

Adopting the standard addition method, add an appropriate amount of polycyclic aromatic hydrocarbon standard solution to 1 g of dye sample, the concentration of the standard addition is 10 mg/kg, and operate according to the provisions of Chapter 8 and Chapter 9; the measured recovery of polycyclic aromatic hydrocarbons (except naphthalene) shall be 70%~120%, and the recovery of naphthalene shall be 60%~120%.