GB 31656.2-2021 English PDF

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GB 31656.2-2021: National food safety standard - Determination of Tylosin residues in aquatic products by high performance liquid chromatography
Status: Valid

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB 31656.2-2021	119	Add to Cart	3 days	National food safety standard - Determination of Tylosin residues in aquatic products by high performance liquid chromatography	Valid

Similar standards

SC/T 3053   GB 31602   GB/T 23493   GB 31656.1   GB 31656.3   GB 31656.11   

Basic data

Standard ID: GB 31656.2-2021 (GB31656.2-2021)
Description (Translated English): National food safety standard - Determination of Tylosin residues in aquatic products by high performance liquid chromatography
Sector / Industry: National Standard
Classification of Chinese Standard: X20
Word Count Estimation: 6,663
Issuing agency(ies): National Health Commission of the People's Republic of China, State Administration for Market Regulation

GB 31656.2-2021: National food safety standard - Determination of Tylosin residues in aquatic products by high performance liquid chromatography

---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 tylosin residues in aquatic products HPLC 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 Tylosin Residues in Aquatic Products by High Performance Liquid Chromatography

1 Scope

This document specifies the sample preparation and high-performance liquid chromatography determination methods for the detection of tylosin residues in aquatic products: This document is applicable to the determination of tylosin residues in edible tissues of fish, shrimp, crab, soft-shell turtle and other aquatic products:

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 remaining tylosin in the sample was extracted with ethyl acetate, defatted with n-hexane, and purified with an SCX solid-phase extraction column under weakly alkaline conditions: Determination by liquid chromatography and quantification by external standard method:

5 Reagents and materials

The reagents used below are all analytically pure reagents unless otherwise noted; 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 Methanol (CH₃OH): chromatographically pure: 5:1:3 n-hexane (C₆Hu): chromatographically pure: 5:1:4 Ethyl acetate (CH₃COOC₂H₅): chromatographically pure: 5:1:5 Dipotassium hydrogen phosphate (K₂HPO₄): 5:1:6 Potassium dihydrogen phosphate (KH₂PO): 5:1:7 Phosphoric acid (H₃PO₄) 5:2 Standard products Tylosin tartrate (CAS number: 74610-55-2): content ≥98%: 5:3 Solution preparation 5:3:1 Phosphate buffer solution I (pH 8:0): Take 0:52 g of potassium dihydrogen phosphate and 16:73 g of dipotassium hydrogen phosphate, dissolve in water and dilute to 500 mL: 5:3:2 Phosphate buffer solution II (pH 4:0): Use phosphoric acid to adjust the pH of phosphate buffer solution I to 4:0: 5:3:3 Dipotassium hydrogen phosphate solution (0:1 mol/L, pH 9:0): Take 1:74 g of dipotassium hydrogen phosphate, dissolve it in water and dilute it to 100 mL: 5:3:4 Potassium dihydrogen phosphate solution (0:01 mol/L, pH 2:5): Take 1:36 g of potassium dihydrogen phosphate, dissolve it in water and dilute it to 1000mL, phosphoric acid Adjust pH to 2:5: 5:4 Preparation of standard solution Tylosin standard stock solution (100 μg/mL): Take about 10 mg of tylosin tartrate standard, weigh it accurately, and add an appropriate amount of acetonitrile to dissolve it: Dissolve and dilute to volume into a 100mL brown volumetric flask, shake well, and get ready: Store in the dark at 2℃~8℃, valid for 1 month: 5:5 Materials SCX solid phase extraction column: 500mg/3mL, or equivalent:

6 Instruments and equipment

6:1 Liquid chromatograph: equipped with UV detector: 6:2 Analytical balance: sensitivity 0:00001g and 0:01g: 6:3 High-speed tissue masher: 6:4 Centrifuge: 5000r/min: 6:5 Vortex mixer: 6:6 Oscillator: 6:7 Rotary evaporator: 6:8 Solid phase extraction device: 6:9 Chicken heart bottle: 100mL: 6:10 Centrifuge tube with stopper: 50mL: 7: Preparation and preservation of samples 7:1 Preparation of samples Prepare samples according to the requirements of Appendix B in GB/T 30891-2014: a) Take the homogenized test sample 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 Stored below -18℃, the validity period is 3 months:

8 Measurement steps

8:1 Extraction Take 5g of the sample (accurate to ±0:05g), put it into a 50mL centrifuge tube with a stopper, add 5mL of phosphate buffer solution I, and vortex to mix for 1 min: Add 25 mL of ethyl acetate, shake and extract for 10 min, centrifuge at 4500 r/min for 5 min, transfer the supernatant to a 100 mL chicken heart bottle, add 25 mL of ethyl acetate, repeat the extraction once, combine the extracts, and evaporate under reduced pressure in a 45°C water bath until nearly dry: 8:2 Purification Dissolve the residue with 1 mL of methanol, transfer to another 50 mL centrifuge tube, and wash with 10 mL of phosphate buffer solution II and 10 mL of n-hexane: Wash the chicken heart bottle, vortex and mix for 2 minutes, combine the washing liquid in the centrifuge tube, vortex and mix, centrifuge at 4500 r/min for 5 minutes, discard the upper n-hexane layer, and take The lower aqueous solution is reserved for later use: Take the SCX solid phase extraction column, activate it with 5 mL of methanol and 5 mL of phosphate buffer solution II, and pass the backup solution through the column (control the flow rate to about 1:5 mL/min): Add 3 mL of water, 5 mL of methanol, 3 mL of water, and hydrogen phosphate in sequence: Wash the column with 3 mL of dipotassium solution and 0:4 mL of methanol, discard the eluate, and drain it: Add 3:0 mL of methanol for elution, collect the eluate, vortex to mix, filter with a 0:45 μm microporous membrane, and wait until machine analysis: 8:3 Preparation of standard curve Precisely measure an appropriate amount of tylosin standard stock solution and dilute it with methanol to make the concentrations 0:050 μg/mL, 0:10 μg/mL, 0:50 μg/mL, 1:00 μg/mL, 2:00 μg/mL, and 5 :00μg/mL series of standard working solutions for liquid chromatography analysis: 8:4 Determination 8:4:1 Liquid chromatography reference conditions a) Chromatographic column: C18 chromatographic column (250mm×4:6mm, 5μm) or one with equivalent performance; b) Detection wavelength: 285nm; c) Mobile phase: A is potassium dihydrogen phosphate solution, B is acetonitrile, and the gradient elution conditions are shown in Table 1; d) Flow rate: 1:0mL/min; e) Column temperature: 35℃; f) Injection volume: 50μL: 8:4:2 Determination method Take 50 μL each of the sample solution and standard solution, perform single-point or multi-point calibration, and quantify the chromatographic peak area according to the external standard method: Standard solution and sample The response value of tylosin in the solution should be within the linear range of instrument detection: According to the retention time of tylosin standard working solution, the external standard Legal quantification: See Appendix A for the chromatogram: 8:4:3 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 drug 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 is 30 μg/kg, and the quantification limit is 50 μg/kg: 10:2 Accuracy This method has a recovery rate of 70% to 110% at the added concentration level of 50μg/kg~500μg/kg: 10:3 Precision The intra-batch relative standard deviation of this method is ≤15%, and the inter-batch relative standard deviation is ≤15%: ......

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