1 Scope
This part of GB/T 18412 specifies the methods for the determination of 12 pyrethroid pesticides (see Annex A) residues in textiles by gas chromatography-electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS).
This part is applicable to textile materials and their products.
2 Principle
Extract the specimen ultrasonically by acetone-n-hexane (1+4), concentrate the extracting solution to a constant volume, and then determine it with a gas chromatography-electron capture detector (GC/ECD) and quantify by external standard method, or determine and confirm it by gas chromatography-mass spectrometry (GC-MS) and quantify by external standard method.
3 Reagents and materials
Unless otherwise specified, all reagents used shall be analytically pure reagents.
3.1 Acetone: residue grade.
3.2 N-hexane: residual grade.
3.3 Anhydrous sodium sulfate: burned at 650℃ for 3 h, and then stored in desiccator for standby after cooling down.
3.4 Acetone-n-hexane (1+4).
3.5 Standard pyrethroid pesticides : purity ≥ 98%, see Annex A.
3.6 Standard stock solution: Accurately weigh an appropriate amount of each standard pyrethroid pesticide separately, and prepare standard stock solution with a mass concentration of 100 μg/mL with n-hexane.
3.7 Mixed standard working solution: Dilute the above solution with n-hexane step by step as required to form series mixed standard working solutions with applicable concentrations.
Note: The validity period of the standard stock solution is 12 months in a refrigerator at 0℃ ~ 4℃, and that of the mixed standard working solution is 6 months in a refrigerator at 0℃ ~ 4℃.
Foreword
1 Scope
2 Principle
3 Reagents and materials
4 Instruments and apparatus
5 Analytical procedure
6 Calculation of results
7 Determination lower limit, recovery rate and precision
8 Test report
Annex A (Normative) List of 12 pyrethroid pesticides
Annex B (Informative) Quantitative and qualitative selected ions of pyrethroid pesticides and determination lower limit
Annex C (Informative) Gas chromatogram (GC-ECD) of standard pyrethroid pesticides
Annex D (Informative) Gas chromatogram-mass spectrogram (GC-MSD) of standard pyrethroid pesticides
