Veterinary drug residue/aquatic product detection

This standard specifies a high-performance liquid chromatography/tandem mass spectrometry method for the determination of 8 nitroimidazole raw materials and 2 residual metabolites in animal derived foods. This standard is applicable to the determination of residues of 4-nitroimidazole, isopropylimidazole, 2-methylimidazole, lornidazole, metronidazole, chloromethylimidazole, dimenidazole, and benzimidazole in pork, chicken, beef, pig liver, chicken liver, cow liver, pig kidney, cow kidney, fish, milk powder, and honey, as well as their metabolites hydroxymethylquine MNZOH (metabolite of metronidazole) and hydroxymethylmethylimidazole HMMNI (metabolite of 2-methylimidazole and lornidazole). 2 Normative References: The clauses in the following documents become the clauses of this standard through the reference surface of this standard. For dated reference documents, all subsequent amendments (excluding corrected content) or revisions are not applicable to this standard. However, parties to agreements based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest version applies to this standard. GB/T 6682 Specification and Test Methods of Water for Analytical Laboratory (GB/T 6682-1992.neq ISO 36961987) 3. Eight kinds of nitroimidazole residues in principle samples, two metabolites were extracted by methanol acetone homogenization or ultrasonic extraction, distributed by ethyl acetate liquid-liquid, purified by gel chromatography (GPC), purified by solid phase extraction (SPE), confirmed by liquid chromatography/tandem mass spectrometry, and quantitatively determined by external standard method. Unless otherwise specified, all reagents and materials are analytical pure, and the water is Grade 1 water according to GB/T 6682. 4.1 Methanol: HPLC grade. 4.2 Acetone: HPLC grade. 4.3 Ethyl acetate: HPLC grade. 4.4 Cyclohexane: HPLC grade. 4.5 Sodium chloride. 4.6 Anhydrous sodium sulfate; Burn at 650 ℃ for 4 hours and store in a sealed container for future use. 4.7 Formic acid: premium grade pure. 4.8 Saturated sodium chloride aqueous solution. 4.9 Diatomaceous algae: 80 to 120 orders. 4.10Ca solid-phase extraction column: 1.0 g.6 ml. 4.11 microporous filter membrane; Organic system, 0.45pam. 4.12 There are 8 types of nitroimidazole technical drugs and 2 standard substances for metabolites; The purity is greater than or equal to 98% (see Appendix A for details). 4.13 Standard stock solution: Accurately weigh an appropriate amount of each standard substance and prepare a standard stock solution with a concentration of 1000 pag/mL using methanol. The solution should be prepared in a brown volumetric flask and stored for 12 months in a refrigerator at 0-4 ℃. 4.14 Mixed intermediate standard solution: Accurately transfer a certain volume of each standard stock solution and dilute it with methanol to form a mixed intermediate standard solution of appropriate concentration. The solution should be prepared in a brown volumetric flask and stored for 6 months in a refrigerator at 0 ℃~4 ℃

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