National food safety standard— Determination of nitrofuran metabolites residues in aquatic products by liquid chromatography-tandem mass spectrometry method
GB 31656.13-2021 National food safety standard - Determination of nitrofuran metabolites residues in aquatic products by liquid chromatography-tandem mass spectrometry method
1 Scope
This document specifies the sample preparation and determination of 3-amino-2-oxazolidinone (AOZ), 5-morpholinomethyl-3amino-2-oxazolidinone (AMOZ), 1-aminohydantoin (AHD) and semicarbazide (SEM) residues by liquid chromatography-tandem mass spectrometry method.
This document is applicable to the determination of nitrofuran metabolites AOZ, AMOZ, AHD and SEM residues in edible tissues of aquatic products such as fish, sea cucumber and turtle, and the determination of AOZ, AMOZ and AHD in edible tissues of crustaceans such as shrimp and crab.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 30891-2014 Practice of sampling plans for aquatic products
3 Terms and definitions
No terms and definitions are listed in this document.
4 Principle
The residual nitrofuran protein-bound metabolites in the test portion are hydrolyzed under acidic conditions, derivated by 2-nitrobenzaldehyde, liquid-liquid extracted by ethyl acetate, purified by high-speed centrifugation, determined by liquid chromatography-tandem mass spectrometry method, and quantified by internal standard method.
5 Reagents and materials
Unless otherwise specified, all reagents used shall be analytically pure reagents and water used shall be Grade I water specified in GB/T 6682.
5.1 Reagents
5.1.1 Methanol (CH3OH): chromatographically pure.
5.1.2 Ammonium acetate (CH3COONH4): chromatographically pure.
5.1.3 Ethyl acetate (C4H8O2): chromatographically pure.
5.1.4 Dimethyl sulfoxide [(CH3)2SO]: chromatographically pure.
5.1.5 2-nitrobenzaldehyde (C7H5NO3): chromatographically pure.
5.1.6 Anhydrous dipotassium hydrogen phosphate (K2HPO4).
5.1.7 Hydrochloric acid (HCl).
5.2 Solution preparation
5.2.1 0.5mol/L hydrochloric acid solution: pipette 42mL hydrochloric acid, dilute it with water to 1,000mL and mix well.
5.2.2 0.002mol/L ammonium acetate solution: take 0.15g ammonium acetate, dissolve and dilute it with water to 1,000mL, and mix well.
5.2.3 0.05mol/L 2-nitrobenzaldehyde solution: take 0.076g 2-nitrobenzaldehyde, dissolve and dilute it with dimethyl sulfoxide to 10mL, and mix well. This solution shall be prepared immediately before use.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents and materials
6 Apparatus
7 Preparation and preservation of test portion
8 Determination steps
9 Calculation and expression of results
10 Sensitivity, accuracy and precision of determination method
Annex A (Informative) Chinese and English names, chemical formula and CAS No. of drugs
Annex B (Informative) Mass chromatogram of characteristic ion
