GB 31656.10-2021 English PDF

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GB 31656.10-2021: National food safety standard - Determination of metaldehyde residues in aquatic products by liquid chromatography-tandem mass spectrometry method
Status: Valid

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB 31656.10-2021	159	Add to Cart	3 days	National food safety standard - Determination of metaldehyde residues in aquatic products by liquid chromatography-tandem mass spectrometry method	Valid

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SC/T 3053   GB 31602   GB/T 23493   GB 31656.16   GB 31656.17   GB 31656.15   

Basic data

Standard ID: GB 31656.10-2021 (GB31656.10-2021)
Description (Translated English): National food safety standard - Determination of metaldehyde residues in aquatic products by liquid chromatography-tandem mass spectrometry method
Sector / Industry: National Standard
Classification of Chinese Standard: X20
Word Count Estimation: 8,834
Issuing agency(ies): National Health Commission of the People's Republic of China, State Administration for Market Regulation

GB 31656.10-2021: National food safety standard - Determination of metaldehyde residues in aquatic products by liquid chromatography-tandem mass spectrometry 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 Determination of metaldehyde residues in aquatic products Liquid chromatography-tandem 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: This document is published for the first time: National food safety standards Determination of metaldehyde residues in aquatic products by liquid chromatography-tandem mass spectrometry

1 Scope

This document specifies the sample preparation and liquid chromatography-tandem mass spectrometry methods for detecting metaldehyde residues in aquatic products: This document is applicable to the detection of metaldehyde residues in edible tissues of fish and shrimp:

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative citations in the text: Among them, the cited documents with dates are: Only the version corresponding to the date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document: document: GB/T 6682 Specifications and test methods for water used in analytical laboratories GB/T 30891-2014 Sampling specifications for aquatic products

3 Terms and definitions

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

4 Principles

The metaldehyde in the sample was extracted by acetonitrile homogenate, and the extract was salted out and purified using N-propylethylenediamine and C18 packing: The liquid chromatography G series Detection by mass spectrometry and quantification by internal standard method:

5 Reagents 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 (CH₈CN): chromatographically pure: 5:1:2 Formic acid (HCOOH): chromatographically pure: 5:1:3 Sodium chloride (NaCl): 5:1:4 Anhydrous magnesium sulfate (MgSO,): 5:2 Preparation of solution 5:2:1 0:1% formic acid solution: Take 1mL of formic acid, add water to dissolve and dilute to 1000mL, and mix well: 5:2:250% acetonitrile solution: Pipette 100mL of acetonitrile, add 100mL of water, and shake well: 5:3 Standard products Metaldehyde and metaldehyde-D16 standard products, the content is ≥95%, see Appendix A: 5:4 Preparation of standard solution 5:4:1 Standard stock solution (100 μg/mL): Take an appropriate amount of metaldehyde and metaldehyde-D16 (equivalent to 10 mg of active ingredient) and weigh them accurately: Dissolve and dilute with acetonitrile respectively to a 100mL volumetric flask, shake well, and get it: Store below -18℃, valid for 6 months: 5:4:2 Standard intermediate solution (5:0μg/mL): Precisely measure 0:5mL each of metaldehyde and metaldehyde-D16 standard stock solution into 10mL respectively: In a volumetric flask, dilute with acetonitrile to the mark, shake well, and get it: Store in a dark place at 2°C to 8°C, and is valid for 1 month: 5:4:3 Standard working solution (0:025 μg/mL): Precisely measure 0:5 mL of metaldehyde and metaldehyde-D16 standard intermediate solutions respectively: In a 10mL volumetric flask, dilute to the mark with acetonitrile, shake well, and get it: Ready to use: 5:5 Materials 5:5:1 N-propylethylenediamine (PSA) filler, 40 mesh to 60 mesh or equivalent: 5:5:2 C filler, 40 mesh to 60 mesh or equivalent: 6Instruments and equipment 6:1 Liquid chromatography-tandem mass spectrometer: equipped with automatic sampler and electrospray ion source: 6:2 Analytical balance: sensitive to 0:01g and 0:00001g: 6:3 Homogenizer, 6:4 Centrifuge tubes: polypropylene plastic centrifuge tubes, 10 mL and 50 mL: 6:5 Centrifuge: 10000 r/min or above: 6:6 Vortex mixer:

7 Preparation and preservation of samples

7:1 Preparation of samples Prepare samples according to the requirements of Appendix B of GB/T 30891-2014: a) Take the homogenized test material as the test material; b) Take the homogenized blank sample as the blank sample; c) Take the homogenized blank sample, add the standard working solution of appropriate concentration, and add the sample as a blank: 7:2 Storage of samples Store below -18℃ and conduct analysis and testing within 3 months:

8 Measurement steps

8:1 Extraction Take 5 g of the sample (accurate to ±0:05 g), put it in a 50 mL centrifuge tube, add 100 μL of metaldehyde-Ds standard working solution (0:25 μg/mL), then add 2:0 mL of water and 10:0 mL of acetonitrile in sequence, and stir at 10000 r /min speed for 1 minute, add 2g of sodium chloride, cover and vortex for 1 minute, then centrifuge at 5000r/min for 2 minutes, collect the supernatant and set aside: 8:2 Purification Take 2:0 mL of the reserve solution and transfer it into a 5 mL centrifuge tube containing 0:3 g of anhydrous magnesium sulfate, 0:1 g of Ci₈, and 0:1 g of PSA: Vortex and mix for 1 min, centrifuge at 5000 r/min for 2 min, and draw 0:5 mL of the supernatant: Dilute the 0:1% formic acid solution to 1:0 mL, mix well, and pass through a 0:22 μm filter for liquid chromatography-tandem mass spectrometry measurement: 8:3 Preparation of standard curve Precisely measure appropriate amounts of 0:25 μg/mL metaldehyde standard working solution and 0:25 μg/mL metaldehyde-D₁s standard working solution, and dilute with 50% acetonitrile solution to contain metaldehyde at a concentration of 0:05 μg/L, 0:10 μg/L, 0:25 μg/L, 0:50 μg/L, 1:0 μg/L, 2:5 μg/L and A series of standard solutions of 5:0 μg/L (internal standard concentrations are all 1:25 μg/L) for liquid chromatography-tandem mass spectrometry determination: Draw a standard curve with the concentration of the standard solution as the abscissa, the metaldehyde quantitative ion pair peak area and the metaldehyde-Ds ion pair peak area ratio as the ordinate: Find the regression equation and correlation coefficient: 8:4 Determination 8:4:1 Liquid Chromatography Reference Conditions a) Chromatographic column: C18 column (50 mm×2:1 mm, 1:7μm) or equivalent; b) Mobile phase: A is 0:1% formic acid solution, B is acetonitrile, and the gradient elution conditions are shown in Table 1; c) Flow rate: 0:3 mL/min; d) Column temperature: 30℃; e) Injection volume: 10μL: 8: 4: Determination method Take the sample solution and standard solution, conduct single-point or multi-point calibration, quantify by chromatographic peak area, and calculate by internal standard method: Standard solution and sample solution The characteristic ion mass chromatographic peak areas of the target drug should be within the linear range of instrument detection: The retention time of metaldehyde in the sample solution Compared with the metaldehyde retention time in the standard working solution, the deviation is within ±2:5%, and the relative ion abundance in the sample solution is consistent with the standard solution: Compared with the relative ion abundance in the solution, it meets the requirements of Table 3: The multiple reaction monitoring chromatogram of the standard solution is shown in Appendix B:1: 8:5 Blank test Take a blank sample and perform parallel operations using the same measurement steps except that no standard solution is added:

9 Calculation and presentation of results

The residual amount of the substance to be tested in the sample is calculated according to the standard curve or formula (1): 10 Sensitivity, accuracy and precision of detection methods 10:1 Sensitivity The detection limit of this method in edible fish and shrimp tissues is 0:50 μg/kg, and the limit of quantification is 1:0 μg/kg: 10:2 Accuracy The recovery rate of this method at the added concentration level of 1:0 μg/kg~2:0 μg/kg is 80%~120%: 10:3 Precision The intra-batch relative standard deviation of this method is ≤10%, and the inter-batch relative standard deviation is ≤15%: ......

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