GB 31658.21-2022 English PDFUS$199.00 · In stock
Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB 31658.21-2022: (National Food Safety Standard Determination of Levamisole Residues in Animal Foods by Liquid Chromatography-Tandem Mass Spectrometry) Status: Valid
Basic dataStandard ID: GB 31658.21-2022 (GB31658.21-2022)Description (Translated English): (National Food Safety Standard Determination of Levamisole Residues in Animal Foods by Liquid Chromatography-Tandem Mass Spectrometry) Sector / Industry: National Standard Classification of Chinese Standard: X04 Word Count Estimation: 9,963 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 31658.21-2022: (National Food Safety Standard Determination of Levamisole Residues in Animal Foods by Liquid Chromatography-Tandem Mass Spectrometry)---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 Determination of levamisole residues in food of animal origin Liquid Chromatography-Tandem Mass Spectrometry 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 levamisole residues in food of animal origin Liquid chromatography-tandem mass spectrometry1 ScopeThis document specifies the sample preparation and liquid chromatography-tandem mass spectrometry method for the detection of levamisole residues in animal foods. This document is applicable to the determination of levamisole residues in muscle, liver, kidney and adipose tissue of pigs, poultry, cattle and sheep.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 methods3 Terms and DefinitionsThis document does not have terms and definitions that need to be defined.4 principlesThe remaining levamisole in the sample was extracted with ethyl acetate under alkaline conditions, extracted with 0.1mol/L hydrochloric acid solution, mixed cation exchange The solid-phase extraction column was replaced for purification, determined by liquid chromatography-tandem mass spectrometry, and quantified by external standard method.5 Reagents or 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 Formic acid (HCOOH). chromatographically pure. 5.1.4 Ethyl acetate (C4H8O2). 5.1.5 Anhydrous sodium sulfate (Na2SO4). 5.1.6 Sodium bicarbonate (NaHCO3). 5.1.7 Sodium carbonate (Na2CO3). 5.1.8 Hydrochloric acid (HCl). 5.1.9 Ammonia (NH3.H2O). 5.2 Solution preparation 5.2.1 Saturated solution of sodium bicarbonate. take 100mL of water, add anhydrous sodium bicarbonate until it is insoluble, take the supernatant, and make it now. 5.2.2 Saturated solution of sodium carbonate. take 100mL of water, add sodium carbonate until it is insoluble, take the supernatant, and make it now. 5.2.3 Carbonate buffer solution. Take 90 mL of saturated sodium bicarbonate solution and 10 mL of saturated sodium carbonate solution, and mix them evenly. 5.2.4 0.1mol/L hydrochloric acid solution. take 9mL of hydrochloric acid, add water to dilute to 1000mL, and mix well. 5.2.5 4% ammonia water in methanol solution. Take 4 mL of ammonia water, dilute it with methanol to 100 mL, mix well, and prepare immediately after use. 5.2.6 0.1% formic acid solution. Take 500 μL of formic acid, dilute to 500 mL with water, and mix well. 5.2.7 10% acetonitrile formic acid solution. take 10mL of acetonitrile, dilute to 100mL with 0.1% formic acid aqueous solution, and mix well. 5.3 Standards Levamisole hydrochloride (Levamisolehydrochloride, C11H12N2S.HCl, CAS number. 16595-80-5), content ≥99%. 5.4 Preparation of standard solution 5.4.1 Standard stock solution. Take an appropriate amount of levamisole hydrochloride standard substance (equivalent to about 10 mg of levamisole), weigh it accurately, add an appropriate amount of methanol to make the solution solution and dilute to a 10mL volumetric flask, and prepare a standard stock solution of levamisole with a concentration of 1mg/mL. 6 months. 5.4.2 Standard working solution. Accurately measure 1mL of standard stock solution, put it in a 100mL volumetric flask, dilute it to the mark with methanol, and prepare a concentration of 10 μg/mL levamisole standard working solution, stored at 4 ℃, valid for 3 months. 5.5 Materials 5.5.1 Mixed cation exchange solid phase extraction column. 60mg/3mL, or equivalent. 5.5.2 Homogeneous ceramics. 5.5.3 Microporous nylon filter membrane. 0.22 μm.6 Instruments and equipment6.1 Liquid chromatography-tandem mass spectrometer. distribution of electrospray ionization source. 6.2 Analytical balance. Sensitivity 0.00001g and 0.01g. 6.3 Vortex mixer. 6.4 Vortex shaker. 6.5 High-speed refrigerated centrifuge. speed ≥ 10000r/min. 6.6 Solid phase extraction device. 6.7 Nitrogen blowing instrument.7 Preparation and storage of samples7.1 Sample preparation Take an appropriate amount of fresh or thawed blank or test tissue, mince it, and homogenize it. 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 a standard solution of appropriate concentration, and add the sample as a blank. 7.2 Sample storage Store below -18°C.8 Measurement steps8.1 Extraction Take 2 g of the sample (accurate to ±0.05 g), put it in a 50 mL polypropylene centrifuge tube (the fat sample needs to be heated in a water bath at 60 °C for 20 min), Add a ceramic homogenate, add carbonate buffer 0.5mL, anhydrous sodium sulfate 2g, ethyl acetate 10mL, vortex for 1min, shake for 5min, Centrifuge at 6000r/min for 5min, take the upper layer of ethyl acetate to another centrifuge tube, repeat the extraction of the residue once with 10mL of ethyl acetate, and combine twice Add 5 mL of 0.1 mol/L hydrochloric acid solution to the extract, shake for 5 min, centrifuge at 6000 r/min for 5 min, take the lower aqueous phase into another centrifuge tube, Add 5 mL of 0.1 mol/L hydrochloric acid solution to the organic phase to repeat the extraction once, combine the two extracts, and set aside. 8.2 Purification Take a mixed-type cation-exchange solid-phase extraction column and activate it with 3 mL of methanol and 3 mL of 0.1 mol/L hydrochloric acid solution in sequence. The flow rate of the column was controlled at 1mL/min~2mL/min, rinsed with 3mL of water and 3mL of methanol in turn, drained, and washed with 3mL of 4% ammonia water and methanol solution. The eluate was collected and blown dry with nitrogen at 40°C. The residue was dissolved in 1.0 mL of 10% acetonitrile formic acid solution, ultrasonicated for 1 min, and passed through 0.22 μm microporous nylon filter membrane for liquid chromatography-tandem mass spectrometry. 8.3 Preparation of matrix-matched standard curve Precisely measure an appropriate amount of standard working solution, dilute it with methanol, and prepare concentrations of 10ng/mL, 20ng/mL, 50ng/mL, 100 ng/mL,.200 ng/mL and 500 ng/mL series of standard solutions, 100 μL each, were added to the extracted and purified In the eluent of the blank sample, dry it with nitrogen gas at 40 °C, dissolve the residue with 1.0 mL of 10% acetonitrile formic acid aqueous solution, sonicate for 1 min, and mix well. Matrix-matched standard solutions with concentrations of 1 ng/mL, 2 ng/mL, 5 ng/mL, 10 ng/mL, 20 ng/mL and 50 ng/mL were prepared. liquid, passed through a microporous nylon filter membrane, and was used for liquid chromatography-tandem mass spectrometry. The concentration of the matching standard solution is the abscissa, and the matrix matching standard curve is drawn. Find the regression equation and correlation coefficient. 8.4 Determination 8.4.1 Reference conditions for liquid chromatography a) Chromatographic column. C18 chromatographic column (50mm×2.1mm, 1.7μm), or equivalent; b) Column temperature. 35°C; c) Injection volume. 2 μL; d) Flow rate. 0.30mL/min; e) Mobile phase. A is 0.1% formic acid solution; B is methanol; the gradient elution program is shown in Table 1. 8.4.2 Reference conditions for mass spectrometry a) Ion source. electrospray ion source; b) Scanning mode. positive ion scanning; c) Detection method. multiple reaction monitoring; d) Ion source temperature. 150°C; e) Desolventization temperature. 500°C; f) Capillary voltage. 0.8kV; g) Qualitative ion pairs, quantitative ion pairs, cone voltage and collision energy are shown in Table 2. 8.4.3 Assay 8.4.3.1 Qualitative determination Under the same test conditions, the retention time of levamisole in the sample solution is relatively deviated from the retention time in the matrix-matched standard working solution within ±2.5%, and the detected relative ion abundance should be consistent with the relative ion abundance of the matrix-matched standard solution with comparable concentration. The allowable deviation should meet the requirements in Table 3. 8.4.3.2 Quantitative determination Take the sample solution and the corresponding matrix-matched standard working solution for single-point or multi-point calibration, and use the external standard method to quantify the peak area. The response values of levamisole in quasi-working solution and sample solution should be within the linear range of instrument detection. See Appendix A for the characteristic ion mass chromatogram of the imidazole matrix-matched standard solution. 8.5 Blank test Except that no sample was added, the determination was carried out in exactly the same manner.9 Calculation and presentation of resultsThe residual amount of the analyte in the sample was calculated according to the standard curve or formula (1). 10 Detection method sensitivity, accuracy and precision 10.1 Sensitivity The detection limit of this method was 0.5 μg/kg, and the limit of quantification was 1.0 μg/kg. 10.2 Accuracy The recovery rate of levamisole in muscle, kidney and adipose tissue was 60%~ 120%, 10μg/kg~20μg/kg added concentration level of recovery was 70%~110%; in liver tissue 1.0μg/kg~10μg/kg The recovery rate at the added concentration level was 60%~120%, and the recovery rate at the added concentration level of 10μg/kg~200μg/kg was 70%~ 110%. 10.3 Precision In this method, the relative standard deviation within the batch was ≤20%, and the relative standard deviation between batches was ≤20%. ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB 31658.21-2022_English be delivered?Answer: Upon your order, we will start to translate GB 31658.21-2022_English as soon as possible, and keep you informed of the progress. 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