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Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB 31659.3-2022: (National Food Safety Standard Determination of Cephalosporin Residues in Milk and Milk Powder by Liquid Chromatography-Tandem Mass Spectrometry) Status: Valid
Basic dataStandard ID: GB 31659.3-2022 (GB31659.3-2022)Description (Translated English): (National Food Safety Standard Determination of Cephalosporin Residues in Milk and Milk Powder by Liquid Chromatography-Tandem Mass Spectrometry) Sector / Industry: National Standard Word Count Estimation: 11,156 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 31659.3-2022: (National Food Safety Standard Determination of Cephalosporin Residues in Milk and Milk Powder 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 cephalosporin residues in milk and milk powder 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 Replacing GB/T 22989-2008 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 replaces GB/T 22989-2008 "Determination of cefapirin, cephalexin, cefuroxime and cefquinome residues in milk and milk powder Compared with GB/T 22989-2008, except for structural adjustment and editorial changes, the main changes are as follows. --- The standard text format is changed to the national food safety standard text format; --- Increase the detection of goat milk in the standard scope; --- Increase the number of drug varieties in the standard range; ---Standard sensitivity is further improved. The release status of previous versions of this document and the documents it replaces are as follows. ---GB/T 22989-2008. National Food Safety Standards Determination of cephalosporin residues in milk and milk powder by liquid chromatography-tandem mass spectrometry1 ScopeThis document specifies cephalexin, cephradine, cefazolin, cefoperazone, cefacetonitrile, cefapirin, cephalosporins in milk, goat milk and milk powder. Sample preparation and liquid chromatography-tandem mass spectrometry method for the detection of serotonin, cefquinoxime and cefotaxime residues. This document is applicable to cephalexin, cephradine, cefazolin, cefoperazone, cefacetonitrile, cefapirin, cephalexin in milk, goat milk and milk powder Determination of residues of serotonin, cefquinome and cefotaxime.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 drug residues in the sample were extracted with phosphate buffer solution, purified by hydrophilic-lipophilic equilibrium solid-phase extraction column, and detected by liquid chromatography-tandem mass spectrometry. determined and quantified by matrix calibration external standard method.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 Methanol (CH3OH). chromatographically pure. 5.1.2 Acetonitrile (CH3CN). chromatographically pure. 5.1.3 Formic acid (HCOOH). chromatographically pure. 5.1.4 n-Hexane (C6H14). 5.1.5 Potassium dihydrogen phosphate (KH2PO4). 5.1.6 Sodium Hydroxide (NaOH). 5.2 Solution preparation 5.2.11 2.5mol/L sodium hydroxide solution. take 50g of sodium hydroxide, add water to dissolve and dilute to 500mL. 5.2.2 30% acetonitrile solution. Take 30mL of acetonitrile and dilute with water to 100mL. 5.2.3 0.05mol/L phosphate buffer solution (pH=8.5). take 6.8g of potassium dihydrogen phosphate, dissolve it in water and dilute it to 1000mL, and use 2.5 mol/L sodium hydroxide solution to adjust the pH to 8.5. 5.2.4 0.1% formic acid solution. Take 1mL of formic acid and dilute it with water to 1000mL. 5.2.5 0.1% formic acid solution-methanol (95.5). take 95mL of 0.1% formic acid solution and 5mL of methanol, and mix well. 5.3 Standards Cefalexin, cephradine, cefazolin, cefoperazone, cefacetonitrile, cefapirin, deacetylcefapirin, ceftaroning, cefquinone Oxime and cefotaxime standard products, the content of which is ≥95%, see Appendix A for details. 5.4 Preparation of standard solution 5.4.1 Standard stock solution. take 10 mg of each standard product, weigh them precisely, dissolve them in an appropriate amount with 30% acetonitrile solution and dilute to 25 mL. A volumetric flask was prepared into a standard stock solution with a concentration of 400 μg/mL. It was stored at -18°C in the dark, and the validity period was 1 month. 5.4.2 Mixed standard stock solution. Accurately pipette 0.25mL of each standard stock solution into a 10mL volumetric flask, and dilute with 30% acetonitrile solution. The solution was released to the mark, and prepared into a mixed standard stock solution with a concentration of 10 μg/mL. Stored in the dark at -18°C, the validity period was 7 days. 5.4.3 Mixed standard working solution. Accurately pipette an appropriate amount of mixed standard stock solution, and dilute it with 0.1% formic acid solution-methanol (95.5) to a concentration of 2.5μg/L, 5.0μg/L, 20μg/L, 100μg/L,.200μg/L and 500μg/L series mixed standard working solutions. Ready to use and prepare. 5.5 Materials 5.5.1 Solid-phase extraction column. hydrophilic-lipophilic balanced solid-phase extraction column, 500mg/6mL, or equivalent. 5.5.2 Syringe filter. made of nylon, with a pore size of 0.22 μm or equivalent.6 Instruments and equipment6.1 Liquid chromatography-tandem mass spectrometer. with electrospray ion source. 6.2 Analytical balance. Sensitivity 0.00001g and 0.01g. 6.3 Nitrogen blowing instrument. 6.4 Solid phase extraction device. 6.5 Vortex mixer. 6.6 Centrifuge tube. polypropylene plastic centrifuge tube, 10mL, 50mL. 6.7 pH meter.7 Preparation and storage of samples7.1 Preparation of samples Take an appropriate amount of fresh or thawed blank or test sample, and homogenize. 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 (accurate to ±0.05g) of milk or goat milk sample or 0.5g (accurate to ±0.01g) of milk powder sample, put it in a 50mL centrifuge tube, add phosphorus 20mL salt buffer solution, vortexed and mixed for 30s, adjusted to pH 8.5 with 2.5mol/L sodium hydroxide solution, set aside. 8.2 Purification Take the solid-phase extraction column and activate it with 5 mL of methanol and 10 mL of phosphate buffer solution in turn. Take the spare solution and pass it through the column until the liquid level reaches the surface of the column bed. Then rinse with 3 mL of phosphate buffer solution and 2 mL of water in sequence, discard all the effluent, elute with 3 mL of acetonitrile, and collect the eluate Add 3 mL of n-hexane to a 10 mL centrifuge tube, vortex and mix for 1 min, let stand for 5 min, discard the upper n-hexane layer, take the acetonitrile layer in 40 °C water Blow dry in a nitrogen bath, add 1.0 mL of 0.1% formic acid solution-methanol (95.5) to dissolve, pass through a 0.22 μm filter membrane, and use for liquid chromatography-tandem mass spectrometry determination. 8.3 Preparation of matrix-matched standard curve Take the blank sample and treat it according to 8.1 and 8.2 in turn, dry it with nitrogen in a water bath at 40°C, and add 1.0 mL of a series of mixed standard working solutions to dissolve it. The residue was passed through a 0.22 μm filter membrane to prepare a series of matrices of 2.5 μg/L, 5.0 μg/L, 20 μg/L, 100 μg/L,.200 μg/L and 500 μg/L Match the standard working solution for the determination of liquid chromatography-tandem mass spectrometry. Take the peak area of the quantitative ion pair as the ordinate, and the concentration of the standard solution as the abscissa, Draw a standard curve. Find the regression equation and correlation coefficient. 8.4 Determination 8.4.1 Reference conditions for liquid chromatography a) Chromatographic column. C18 chromatographic column (100mm×2.0mm, 1.7μm) or equivalent; b) Mobile phase. A is 0.1% formic acid solution, B is methanol, and the gradient elution program is shown in Table 1; c) Flow rate. 0.3mL/min; d) Column temperature. 35°C; e) Injection volume. 10 μL. 8.4.2 Reference conditions for mass spectrometry a) Ion source. Electrospray (ESI) ion source; b) Scanning mode. positive ion scanning; c) Detection method. multiple reaction monitoring (MRM); d) Capillary voltage..2000V; e) RF lens voltage. 0.5V; f) Ion source temperature. 150°C; g) Desolvation temperature. 500°C; h) Cone gas flow rate. 50L/h; i) Desolvation gas flow rate. 1000L/h; j) Secondary collision gas. argon; k) See Table 2 for qualifier ion pairs, quantifier ion pairs, collision energy and cone voltage. 8.4.3 Assay Take the sample solution and the matrix-matched standard solution for single-point or multi-point calibration, and use the external standard method to quantify the chromatographic peak area. The matrix-matched standard solution The characteristic ion mass chromatographic peak area of the target drug in the solution and the sample solution should be within the linear range of the instrument detection, if it exceeds the linear range range, the matrix matching standard solution and the test solution should be diluted accordingly and re-measured. The retention time of the substance to be tested in the test solution is different from that of the matrix Match the ratio of the retention time of the substance to be tested in the standard working solution, the deviation is within ±2.5%, and the relative abundance of ions in the sample solution is consistent with that of the matrix. Compared with the relative abundance of ions in the matching standard solution, if it meets the requirements of Table 3, it can be determined that the corresponding substance to be tested exists in the sample. The standard solution See Appendix B for the liquid multiple reaction monitoring chromatogram. 8.5 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 drug to be tested in the sample was calculated according to the standard curve or formula (1). 10 Sensitivity, accuracy and precision of detection method 10.1 Sensitivity In this method, the detection limits of cefoperazone, cefacetonitrile and cefazolin in milk and milk powder were 2.0 μg/kg and 20 μg/kg, respectively. The limits of detection were 4.0 μg/kg and 40 μg/kg respectively; the detection limits of other cephalosporins and deacetylcefapirin in milk and milk powder were The limits of quantitation were 1.0 μg/kg and 10 μg/kg respectively. 10.2 Accuracy The recoveries of this method were 60%-120% at the spiked concentration levels of 1.0 μg/kg-200 μg/kg. 10.3 Precision The intra-assay relative standard deviation of this method was ≤15%, and the inter-assay relative standard deviation was ≤20%. ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB 31659.3-2022_English be delivered?Answer: Upon your order, we will start to translate GB 31659.3-2022_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB 31659.3-2022_English with my colleagues?Answer: Yes. 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