GB 31658.8-2021 English PDF

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GB 31658.8-2021: National food safety standard - Determination of pyrethroid residues in animal derived food by gas chromatography-mass Spectrometric method
Status: Valid

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB 31658.8-2021	159	Add to Cart	3 days	National food safety standard - Determination of pyrethroid residues in animal derived food by gas chromatography-mass Spectrometric method	Valid

Similar standards

GB 31650.1   GB/T 37517   GB/T 30636   GB 31658.1   GB 31658.12   GB 31658.11   

Basic data

Standard ID: GB 31658.8-2021 (GB31658.8-2021)
Description (Translated English): National food safety standard - Determination of pyrethroid residues in animal derived food by gas chromatography-mass Spectrometric method
Sector / Industry: National Standard
Classification of Chinese Standard: X04
Word Count Estimation: 8,841
Issuing agency(ies): National Health Commission of the People's Republic of China, State Administration for Market Regulation

GB 31658.8-2021: National food safety standard - Determination of pyrethroid residues in animal derived food by gas chromatography-mass Spectrometric method

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
National food safety standards Pyrethroids in animal foods Determination of residues gas chromatography-mass spectrometry National Standards of People's Republic of China Released by the National Health Commission of the People's Republic of China State Administration for Market Regulation Ministry of Agriculture and Rural Affairs of the People's Republic of China

Foreword

This document complies with the provisions of GB/T 1:1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting:

1 Scope

This document specifies the sample preparation and gas chromatography-mass spectrometry methods for the detection of pyrethroid drug residues in animal foods: This document applies to single or multiple versions of deltamethrin, bifenthrin, fluvalerate, fluvalinate, tefluthrin and fenvalerate in the muscle, fat and liver of cattle, sheep and pigs: Determination of drug residues: 2Normative reference documents The contents of the following documents constitute essential provisions of this document through normative references in the text: Among them, for dated reference documents, only the version corresponding to the date applies to this document; for undated reference documents, the latest version (including all amendments) applies to this document: GB/T 6682 Specifications and test methods for water used in analytical laboratories

3 Terms and definitions

There are no terms or definitions to be defined in this document:

4 principles

The remaining pyrethroid drugs in the sample were extracted with acetonitrile, purified with a solid phase extraction column, measured by gas chromatography-mass spectrometry, and quantified by the external standard method: 5Reagents and Materials Unless otherwise specified, all reagents are of analytical grade and the water is first-grade water that complies with GB/T 6682: 5:1 Reagents 5:1:1 Acetonitrile (CH₃CN): chromatographically pure: 5:1:2 n-hexane (C₅Hu): chromatographically pure: 5:1:3 Sodium chloride (NaCD): 5:1:4 Anhydrous sodium sulfate (Na₂SO₄): 5:1:5 Benzene (C₆H₆): chromatographically pure: 5:1:6 Acetone (CH₃COCH₃): chromatographically pure: 5:2 Standard products Deltamethrin content ≥99:7%, bifenthrin content ≥98%, flumethrin content ≥87:5%, fluvalinate content ≥94%, tefluthrin content ≥98%, fenvalerate content ≥98% Ester content ≥99%, see Appendix A: 5:3 Preparation of standard solution 5:3:1 Standard stock solution: Take 10 mg each of deltamethrin, bifenthrin, fluvalerate, fluvalinate, tefluthrin and fenvalerate standard products, weigh them accurately, and add benzene Dissolve an appropriate amount, dilute with acetone to a 100mL volumetric flask, shake well, and prepare deltamethrin, bifenthrin, fluvalerate, fluvalinate, sevfluthrin and fenvalerate Standard stock solution: Store at -18℃, valid for 3 months: 5:3:210 μg/mL mixed standard working solution: Precisely measure 1 mL of each of the above standard stock solutions into a 10 mL volumetric flask, dilute to the mark with acetone, and prepare a mixed standard working solution with a concentration of 10 μg/mL: Store at 2℃~8℃, valid for 1 month: 5:3:31:0 μg/mL mixed standard working solution: Precisely measure 1 mL of the 10 μg/mL mixed standard working solution in a 10 mL volumetric flask, dilute to the mark with acetone, and prepare a mixed standard working solution with a concentration of 1:0 μg/mL: Store at 2℃~8℃, valid for 1 month: 5:4 Materials Neutral alumina solid phase extraction column: 500 mg/6mL, or equivalent: 6Instruments and equipment 6:1 Gas Chromatograph-Mass Spectrometer: Equipped with electrospray ion source: 6:2 Analytical balance: sensitive to 0:00001 g and 0:01g: 6:3 High-speed centrifuge: 6:4 Vortex mixer: 6:5 Horizontal Oscillator: 6:6 Tissue homogenizer: 6:7 Solid phase extraction device: 6:8 Nitrogen blower:

7 Preparation and preservation of samples

7:1 Preparation of samples Take an appropriate amount of fresh or thawed blank or test tissue, mince it, and homogenize it: a) Take a homogeneous test sample as a test material; b) Take a homogeneous blank sample as a blank sample; c) Take a homogeneous blank sample, add standard working solution of appropriate concentration, and add the sample as a blank: 7:2 Storage of samples Store below -18℃:

8 Measurement steps

8:1 Extraction Weigh 5g of the sample (accurate to ±0:02g), put it in a 50mL polypropylene centrifuge tube, add 4g of sodium chloride and 25mL of acetonitrile, homogenize for 1 minute, shake for 15 minutes, centrifuge at 6000r/min for 5 minutes, and take the supernatant In another centrifuge tube, add 15 mL of acetonitrile to the residue and repeat the extraction once: Combine the supernatants, add 4 g of anhydrous sodium sulfate, shake, and centrifuge at 4°C and 1000 r/min for 10 min: Take the supernatant and set aside: 8:2 Purification Take a neutral alumina solid-phase extraction column and activate it with acetonitrile twice, 5 mL each time: Pass the standby solution through the column and elute with 10 mL of acetonitrile: Collect all eluents, rotary evaporate to dryness at 50°C, add 1:0 mL of n-hexane to dissolve, filter, and use for gas chromatography-mass spectrometry measurement: 8:3 Preparation of matrix matching standard curve Precisely measure 0:01mL, 0:02mL, 0:05 mL of 1:0μg/mL mixed standard working solution, and 10μg/mL pyrethroid mixed standard: Working solutions 0:01mL, 0:05mL and 0:10mL were added to 6 portions of the blank sample concentrate processed by the sample pretreatment step, and diluted to 1mL with n-hexane to obtain concentrations of 10ng/mL, 20ng/mL and 50ng/mL: mL, 100 ng/mL, 500 ng/mL, and 1000 ng/mL matrix-matched series standard solutions, filtered, and used for gas chromatography-mass spectrometry determination: Using the measured characteristic ion mass chromatographic peak area as the ordinate and the corresponding standard solution concentration as the abscissa, draw a matrix matching standard curve: Find the regression equation and correlation coefficient: 8:4 Determination 8:4:1 Gas Chromatography Reference Conditions a) Chromatographic column: DB-1 (100% dimethylpolysiloxane) capillary column: 30m×0:25 mm, film thickness 0:25μm, or equivalent; b) Chromatographic column temperature: starting column temperature is 70℃, rising to 250℃ at 30℃/min, rising to 274℃ at 3℃/min, rising to 294℃ at 20℃/min, rising to 30℃/min at 30℃/min: 300℃, keep for 2 minutes; c) Carrier gas: high purity helium, column flow rate 1:3mL/min; d) Split: Splitless injection; e) Injection volume: 1μL; f) Inlet temperature: 280℃; g) Interface temperature: 270℃: 8:4:2 Mass spectrometry reference conditions a) Ion source: NCI source; b) Reaction gas: CH₄ (purity greater than 99:99%); c) Ion source temperature: 150℃; d) Ionization voltage: 0:98 kV; e) Quadrupole mass analyzer temperature: 150℃; f) Electron energy: 235 eV; g) Filament current: 44:5μA; h) Solvent delay time: 5:0 min; i) Data collection method: Select ion monitoring method: See Table 1 for specific parameters: 8:4:3 Determination method Take the sample solution and the matrix-matching standard solution, perform single-point or multi-point calibration, and quantify by chromatographic peak area according to the external standard method: The characteristic ion mass chromatographic peak areas of the target drug in the matrix-matched standard solution and the sample solution should be within the linear range of instrument detection: The characteristic ion mass chromatographic peak areas of pyrethroid drugs in the sample solution should be within the linear range of instrument detection: Compared with the relative ion abundance in the matrix-matched standard solution, the relative ion abundance in the sample solution meets the requirements of Table 2: The characteristic ion mass chromatograms in the standard solution are shown in the appendix: Record B: 8:5 Blank test Take a blank sample and perform parallel operations using the same measurement steps except that no standard solution is added: 9Result calculation and presentation The residual amount of the substance to be tested in the sample is calculated according to formula (1): 10 Sensitivity, accuracy and precision of detection methods 10:1 Sensitivity The detection limit of this method is 3μg/kg, and the quantification limit is 10μg/kg: 10:2 Accuracy The recovery rate of this method at the added concentration level of 10 μg/kg to 500 μg/kg is 70% to 120%: 10:3 Precision The intra-batch relative standard deviation of this method is ≤20%, and the inter-batch relative standard deviation is ≤20%: ......

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