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GB 5009.124-2016: National food safety standard - Determination of Amino Acid in Foods Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB 5009.124: Historical versions
Similar standardsGB 5009.124-2016: National food safety standard - Determination of Amino Acid in Foods---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB5009.124-2016GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA National Food Safety Standard – Determination of Amino Acid in Foods Issued on. DECEMBER 23, 2016 Implemented on. JUNE 23, 2017 Issued by. National Health and Family Planning Commission of PRC; China Food and Drug Administration. Table of ContentsForeword... 3 1 Scope... 4 2 Principle... 4 3 Reagents and Materials... 4 4 Instrument and Equipment... 5 5 Analytical Procedures... 6 6 Expression of Analytical Results... 8 7 Precision... 10 8 Others... 10 Appendix A Chromatogram... 12ForewordThis Standard replaces GB/T 5009.124-2003 Determination of Amino Acid in Foods. Compared with GB/T 5009.124-2003, this Standard has the major changes as follows. --- Modify the standard name into “National Food Safety Standard – Determination of Amino Acid in Foods”; --- Expand the applicable scope; --- Add the limit of detection and quantitative limit of the method; --- Modify the result calculation formula. National Food Safety Standard – Determination of Amino Acid in Foods1 ScopeThis Standard specifies using the amino acid analyzer (ninhydrin post-column derivatization ion exchange chromatography) to determine the amino acid in foods. This Standard is applicable to determine the amino acid hydrolyzed by acid in foods, there are totally 16 kinds of amino acids such as aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, and arginine.2 PrincipleThe protein in food is hydrolyzed by hydrochloric acid into free amino acid; after being separated by ion exchange column, it occurs color reaction with ninhydrin solution; then determine the amino acid content through the visible light spectrophotometer.3 Reagents and MaterialsUnless otherwise specified, the reagents used in this method are analytically pure; while water is Class-I water stipulated in GB/T 6682. 3.1 Reagents 3.1.1 Hydrochloric acid (HCl). concentration≥36%, guarantee reagent. 3.2 Reagents preparation 3.2.1 Hydrochloric acid solution (6mol/L). take 500mL of hydrochloric acid, dilute with water to 1000mL, mix evenly. 3.2.2 Refrigerant. mix the commercial salt and ice by the mass ratio of 1.3. 3.3 Standard substance 3.3.1 Mixed amino acid standard solution. standard solution approved by the state or awarded the standard substance certificate by the state. 3.3.2 16 individual amino acid standard substance. solid with purity≥98%. 3.4 Preparation of standard solution 3.4.1 Mixed amino acid standard stock solution (1µmol/mL). separately and accurately take individual amino acid standard substances (accurate to 0.00001g) into the same 50mL beaker; use 8.3mL of 6mol/L hydrochloric acid solution to dissolve;4 Instrument and Equipment4.1 Laboratory used tissue crusher and grinder. 4.2 Homogenizer. 4.7 Electric blower thermostat or hydrolysis furnace. 4.8 Test tube concentrator or parallel evaporator (with supporting 15mL~25mL test tube). 4.9 Amino acid analyzer. ninhydrin post-column derivatization ion exchange chromatography.5 Analytical Procedures5.1 Specimen preparation Crush the solid or semi-solid specimen by tissue crusher or grinder; use the homogenizer to homogenize the liquid specimen into homogenate, sealed and frozen to store; when analyzing, thaw it to use. 5.2 Specimen weighing For sample with good uniformity such as milk powder, etc., accurately weigh a certain quantity of specimen (accurate to 0.0001g); so that the protein content in the specimen is in the range of 10mg~20mg. For samples with unknown protein content, the protein content in the specimen can be measured firstly. Then place the weighed specimen into the hydrolysis tube. 5.3 Specimen hydrolysis According to the protein content in the specimen, add 10mL~15mL of 6mol/L hydrochloric acid solution into the hydrolysis tube. For the specimen with high water content and low protein content, such as beverages, fruits, vegetables, etc., firstly add the same volume of hydrochloric acid to mix evenly, after that supplement by 6mol/L hydrochloric acid solution to about 10mL. Continue to add 3 drops ~ 4 drops of phenol into the hydrolysis tube. 5.4 Determination 5.4.1 Instrument conditions Inject the mixed amino acid standard working solution into the automatic amino acid analyzer; refer to the test protocol and instrument manual of the amino acid analyzer stipulated in JJG1064-2011; appropriately adjust the instrument operation procedures, parameters, and reagent ratio of buffer solution; confirm the instrument operating conditions. 5.4.2 Chromatographic reference conditions6 Expression of Analytical Results6.1 Calculation of individual amino acids in mixed amino acid standard stock solution 6.2 Calculation of amino acid content in the sample The amino acid content in the sample assay solution can be calculated by Formula (2).7 PrecisionThe absolute difference between two independent measurement results obtained under the repeatability conditions shall not exceed 12% of the arithmetic mean.8 OthersWhen the specimen is solid or semi-solid, the maximum specimen quantity is 2g; the dissolution volume after drying is 1mL; the detection limits and quantitative limits of each amino acid can refer to Table 3.Appendix AChromatogram The chromatogram of mixed amino acid standard working solution can refer to Table A.1. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
