GB/T 39076-2020 English PDF (GBT39076-2020)

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GB/T 39076-2020: Textiles--Determination of neonicotinoid pesticide residues
GB/T 39076-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.080.01
W 04
Textiles - Determination of neonicotinoid pesticide
residues
ISSUED ON: JULY 21, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Principles ... 4 
4 Reagents and materials ... 4 
5 Apparatus and equipment ... 5 
6 Analytical procedures ... 5 
7 Calculation and presentation of results ... 7 
8 Low limit of determination and precision ... 8 
9 Test report ... 8 
Appendix A (Normative) List of 7 neonicotinoid pesticides ... 10 
Appendix B (Informative) Mass spectrometry conditions ... 11 
Appendix C (Informative) Total ion chromatograms of liquid chromatography-
tandem mass spectrometry mixed standard solutions of 7 neonicotinoid
pesticides ... 12 
Textiles - Determination of neonicotinoid pesticide
residues
Warning - The personnel using this standard shall have practical
experience in formal laboratory work. This standard does not point out all
possible safety issues. It is the user's responsibility to take appropriate
safety and health measures, and to ensure compliance with the
conditions stipulated by relevant national laws and regulations.
1 Scope
This standard specifies the method of use of liquid chromatography-tandem
mass spectrometry (LC-MS/MS) for the determination of 7 neonicotinoid
pesticide residues in textiles.
This standard applies to all types of textile products.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 6682 Water for analytical laboratory use - Specification and test
methods
3 Principles
The specimen is ultrasonically extracted by acetonitrile; the extract is filtered
through a filter membrane, then measured and confirmed by liquid
chromatography-tandem mass spectrometry (LC-MS/MS), quantified by
external standard method.
4 Reagents and materials
4.1 Acetonitrile: Chromatographically pure.
4.2 The 7 standard neonicotinoid pesticides: purity ≥ 98%, as shown in
Appendix A.
4.3 Standard stock solution (approximately 1000 mg/L): Respectively
accurately weigh appropriate amounts of neonicotinoid pesticide standard
products (accurate to 0.0001 g). Use acetonitrile (4.1) to prepare each
substance to the standard stock solution which has a mass concentration of
approximately 1000 mg/L.
Note: When stored at 0 °C ~ 4 °C in the dark, the validity period of the standard stock
solution is 12 months.
4.4 Mixed standard working solution (approximately 10 mg/L): Accurately
pipette an appropriate amount of standard stock solution (4.3). Use acetonitrile
(4.1) to prepare a mixed standard working solution which has a concentration
of approximately 10 mg/L. Then, prepare the standard working solution of other
concentrations as needed.
Note: When stored at 0 °C ~ 4 °C in the dark, the validity period of the mixed standard
working solution is 3 months.
4.5 Water: Class II water that meets the requirements of GB/T 6682.
5 Apparatus and equipment
5.1 Liquid chromatography-tandem mass spectrometer (LC-MS/MS): It is
equipped with electrospray ionization source (ESI).
5.2 Ultrasonic generator: The working frequency is 40 kHz.
5.3 Balance: Sensitivity is 0.0001 g and 0.01 g, respectively.
5.4 Conical flask: It has a ground stopper; the capacity is 100 mL.
5.5 Polytetrafluoroethylene filter membrane: The pore size is 0.22 μm.
6 Analytical procedures
6.1 Extraction
Take a representative sample. Cut it into small pieces below 5 mm × 5 mm. Mix
well. Weigh 1.0 g (accurate to 0.01 g) and mix the specimen uniformly. Place it
in a conical flask (5.4). Accurately add 20 mL of acetonitrile (4.1). Close the
stopper. Place the conical flask in the ultrasonic generator (5.2). Extract it at
room temperature for 60 minutes. Use polytetrafluoroethylene filter membrane
(5.5) to filter the sample solution into a sample bottle, which is used for LC-
MS/MS analysis.
Where:
Xi - The content of neonicotinoid pesticide i in the specimen, in milligrams
per kilogram (mg/kg);
ci - The concentration of neonicotinoid pesticide i in the sample as calculated
from the standard curve, the unit is milligrams per liter (mg/L);
V - Volume of sample liquid, the unit is milliliters (mL);
F - Dilution factor;
m - The mass of the specimen, in grams (g).
7.2 Results presentation
The test results are represented by the test results of various neonicotinoid
pesticides. The calculation results are kept to one decimal place. When it is
below the lower limit of determination, the test result is "not detected".
8 Low limit of determination and precision
8.1 Lower limit of determination
The lower limit of determination is 0.2 mg/kg.
8.2 Precision
In the same laboratory, when the same operator uses the same equipment,
according to the same test method, to carry out tests of same tested object
independently in a short time, at the 95% confidence level, the absolute
difference of the two independent test results obtained is not more than 20% of
the arithmetic mean of the two measured values.
9 Test report
The test report shall give at least the following contents:
a) Sample description;
b) Number of this standard;
c) Test results;