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Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB 31656.16-2022: (National food safety standards - Determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in aquatic products - gas chromatography) Status: Valid
Basic dataStandard ID: GB 31656.16-2022 (GB31656.16-2022)Description (Translated English): (National food safety standards - Determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in aquatic products - gas chromatography) Sector / Industry: National Standard Classification of Chinese Standard: X04 Word Count Estimation: 10,141 Date of Issue: 2022-09-20 Date of Implementation: 2023-02-01 Issuing agency(ies): National Health Commission of the People's Republic of China, State Administration for Market Regulation GB 31656.16-2022: (National food safety standards - Determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in aquatic products - gas 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 Health Commission of the People's Republic of China National Food Safety Standards Chloramphenicol, thiamphenicol, florfenicol and fluorobenzene in aquatic products Determination of Nicoamide Residues by Gas Chromatography National Standards of People's Republic of China release State Administration for Market Regulation Ministry of Agriculture and Rural Affairs of the People's Republic of China forewordThis document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1.Structure and Drafting Rules for Standardization Documents" drafting. This document is published for the first time. National Food Safety Standards Determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in aquatic products gas chromatography1 ScopeThis document specifies the sample preparation and gas chromatographic determination for the determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in aquatic products method. This document is applicable to the residues of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine in edible tissues of fish, shrimp, turtle, shellfish, sea cucumber and other aquatic products. Quantitative determination.2 Normative referencesThe content in the following documents constitutes the essential provisions of this document through normative references in the text. Among them, the dated reference documents, Only the version corresponding to the date applies to this document; for undated references, the latest version (including all amendments) applies to this document document. GB/T 6682 Analytical laboratory water specifications and test methods GB/T 30891-2014 Sampling Specifications for Aquatic Products3 Terms and DefinitionsThis document does not have terms and definitions that need to be defined.4 principlesThe residual chloramphenicol, thiamphenicol, florfenicol and florfenicol amine in the sample were extracted with ethyl acetate under alkaline conditions and removed with n-hexane. Lipid, solid phase extraction column purification, silanization reagent derivatization, gas chromatography detection, external standard method quantification.5 Reagents and materialsUnless otherwise specified, all reagents are of analytical grade, and the water is first-class water in accordance 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 (C6H14). chromatographically pure. 5.1.4 Acetic acid (CH3COOH). chromatographically pure. 5.1.5 Ethyl acetate (C4H8O2). chromatographically pure. 5.1.6 Toluene (C7H8). chromatographically pure. 5.1.7 Concentrated ammonia water (NH3.H2O). 5.1.8 N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). C8H18F3NOSi2. 5.1.9 Trimethylchlorosilane (TMCS). C3H9ClSi. 5.2 Solution preparation 5.2.1 Ethyl acetate-ammonia water. Take 2mL of concentrated ammonia water and dilute it to 100mL with ethyl acetate. 5.2.2 Methanol-ammonia water. take 2mL of concentrated ammonia water and dilute to 100mL with methanol. 5.2.3 5% acetic acid solution. Take 5mL of acetic acid and dilute it with water to 100mL. 5.2.4 Derivatization reagent. take N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and trimethylchlorosilane (TMCS), Ratio of 99.1 mixed. Now ready to use. 5.3 Standards Chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine, the content of which was ≥98%. See Appendix A for details. 5.4 Preparation of standard solution 5.4.1 Standard stock solution. take 15 mg each of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine standard products, weigh them accurately, add acetonitrile Appropriate amount to dissolve and dilute to a 100mL brown volumetric flask, and prepare a standard stock solution with a concentration of 150μg/mL. Below -18°C Stored and valid for 3 months. 5.4.2 Mixed standard working solution. Accurately measure 1 mL of chloramphenicol standard stock solution, thiamphenicol, florfenicol and florfenicol amine respectively. 10mL in a 50mL volumetric flask, dilute to the mark with acetonitrile to make chloramphenicol concentration 3μg/mL, thiamphenicol, florfenicol and florfenicol The mixed standard working solution with chloramine concentration of 30 μg/mL was stored below -18 ℃, and the validity period was 1 month. 5.5 Materials 5.5.1 MCX solid-phase extraction column. 60mg/3mL, or equivalent. 5.5.2 Pipette. 20μL~200μL,.200μL~1000μL. 5.5.3 Chicken heart bottle. 100mL. 5.5.4 Polyethylene centrifuge tubes. 15mL, 50mL, with stoppers. 5.5.5 Glass centrifuge tube. 10mL, with stopper. 5.5.6 Brown reaction bottle. specification 2mL.6 Instruments and equipment6.1 Gas chromatograph equipped with 63Ni electron capture detector. 6.2 Homogenizer. 6.3 Rotary evaporator. 6.4 Centrifuge. 6.5 Vortex mixer. 6.6 Analytical balance. Sensitivity 0.00001g and 0.01g. 6.7 Nitrogen blowing instrument. 6.8 Ultrasonic cleaner. 6.9 Solid phase extraction device.7 Preparation and storage of samples7.1 Preparation of samples Prepare samples according to the requirements of Appendix B of GB/T 30891-2014. a) Take the homogenized test sample as the test sample; 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°C.8 Measurement steps8.1 Extraction Take 5g of the sample (accurate to ±0.05g), put it in a 50mL stoppered glass centrifuge tube, add 20mL of ethyl acetate-ammonia water, vortex immediately 1 min, ultrasonication for 15 min, centrifugation at 4000r/min for 5 min, the supernatant was taken into a 100 mL chicken heart bottle, the extraction was repeated once, and the supernatant was combined. Add 3 mL of 5% acetic acid solution, oscillate to mix, and evaporate at 40 °C to about 1.5 mL, set aside. 8.2 Purification Take the spare solution in a 10mL centrifuge tube, wash the chicken heart bottle with 1.5mL of 5% acetic acid, and put the washing solution in the centrifuge tube. Add 5mL of n-hexane, vortex Mix for 1 min, centrifuge at 4000r/min for 5 min, take the water layer, repeat degreasing once with 5 mL of n-hexane, take the water layer, and set aside. Take the MCX solid-phase extraction column, activate it with 3mL of methanol and 3mL of water successively, take the spare solution degreased by n-hexane, pass it through the column, and wash it with 5% ethyl alcohol. acid solution 2mL, discard the eluent, elute with methanol-ammonia 6mL, collect the eluate, blow it with nitrogen at 65°C until it is nearly dry, and then wash it with methanol successively. 1 mL of ethyl acetate and 1 mL of ethyl acetate were used to wash the centrifuge tube wall, blown with nitrogen gas until nearly dry, and set aside. 8.3 Derivation 8.3.1 Derivatization of samples Take the dried extract, add 100 μL of acetonitrile to redissolve, transfer to a 2 mL brown reaction bottle, wash with 100 μL and merge into the brown reaction bottle. Add 100 μL of derivatization reagent to the reaction bottle, cap and vortex mix for 10 s, and react in an oven at 60 °C for 30 min. Cool to room temperature, 50 °C~ Blow dry with nitrogen at 55°C, add 1.0 mL of toluene accurately, vortex and mix well, and use for gas chromatograph determination. 8.3.2 Derivatization of standard working solution Take an appropriate amount of mixed standard working solution of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in a 2 mL brown reaction bottle, and place in nitrogen at 50 °C. Blow dry. Follow the steps in 8.3.1 below. 8.4 Preparation of standard curve Accurately measure the appropriate amount of standard working solutions of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine, and dilute the concentration of chloramphenicol with acetonitrile to 1.0 μg/L, 1.5 μg/L, 5.0 μg/L, 15.0 μg/L, 50.0 μg/L, 150.0 μg/L, thiamphenicol, florfenicol, florfenicol Concentrated amine A series of standard solutions with concentrations of 10.0 μg/L, 15.0 μg/L, 50.0 μg/L, 150.0 μg/L, 500.0 μg/L and 1500.0 μg/L were obtained by derivatization. After biochemistry, it is used for gas chromatography determination. With the measured peak area as the ordinate and the corresponding concentration of the standard solution as the abscissa, draw a standard curve. Return Regression equations and correlation coefficients. 8.5 Determination 8.5.1 Chromatographic conditions a) Chromatographic column. DB-5MS quartz capillary column (30m×0.25mm, film thickness 0.25μm), or equivalent; b) Injection method. splitless injection; c) Carrier gas. nitrogen, purity 99.999%; d) Column flow rate. 1.0mL/min, makeup is 25mL/min; e) The inlet temperature is 230°C, and the detector temperature is 310°C; f) Column temperature program. initially keep at 80°C for 1 min, then raise the temperature to 280°C at 30°C/min, and keep for 5 min; g) Injection volume. 1.0 μL. 8.5.2 Determination method Take the sample solution and the corresponding standard solution for single-point or multi-point calibration, and calculate the peak area according to the external standard method. Standard solution and sample solution The response values of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine should be within the linear range of instrument detection. Under the above chromatographic conditions, See Appendix B for the gas chromatogram of the standard solution. 8.5.3 Blank test Take the blank sample, except that no drug is added, the same measurement steps are used for parallel operation.9 Calculation and presentation of resultsThe residual amount of the analyte in the sample is calculated according to the standard curve or formula (1). 10 Method sensitivity, accuracy and precision 10.1 Sensitivity The detection limit of chloramphenicol in this method was 0.1 μg/kg, and the detection limits of thiamphenicol, florfenicol and florfenicol amine were all 1.0 μg/kg. The limit of quantification of chloramphenicol was 0.3 μg/kg, and that of thiamphenicol, florfenicol and florfenicol amine were all 3.0 μg/kg. 10.2 Accuracy The recovery rate of chloramphenicol in this method was 70%~120% at the level of 0.3μg/kg~30.0μg/kg; thiamphenicol, florfenicol and The recoveries of florfenicol amine were 70%-120% at the spiked levels of 3.0 μg/kg-300 μg/kg. 10.3 Precision In this method, the relative standard deviation within the batch was ≤20%, and the relative standard deviation between batches was ≤20%. ...... |
