1、中华人民共和国出入境检验检疫行业标准SNjT 1954-2007 进出口冰鲜肉中二氧化氯残留量的检验方法分光光度法Determination of chlorine dioxide residues in iced meat for import and export Spectrophotometric method 2007-08-06发布2008-03-01实施A罕5古部九三皱电毛主j曲同时7中华人民共和国发布国家质量监督检验检症总局中华人民共和同出人境检验检疫行业标准迸出口冰鲜肉中二氧化氯残留量的检验方法分光光度法S/T 1954-2007 4幡巾因标准出版社出版北京复兴门外三里河北街
2、16号自j，ifZ绚码:1000-Ei 网址电话6852394668517548 中国标准出版社秦皇岛印刷厂印刷3峰开本880X1230 1/16 印张0.75字数16千字200年11月第一版20071f 11月第次印刷印数1-2000 峙书号15;:;066 2-18236 定价8.00元前言本标准由国家认证认可监督管理委员会提出并归口。本标准起草单位:中华人民共和国吉林出入境检验检疫局。本标准主要起草人z徐立明、周晓、陈明岩、牟峻。本标准系首次发布的出人境检验检疫行业标准。SN/T 1954-2007 I 进出口冰鲜肉中二氧化氯残留量的检验方法分光光度法1 范围本标准规定了冰鲜肉中二氧化氮
3、残留量的分光光度检测方法.本标准适用于冰鲜鸡肉中二氧化氯残留量的测定。2 方法提耍 采用分光光度法在552nm处测3 试剂和材料3. 1 丙二酸。3.2 乙二胶囚乙酸二纳(EDTAX.3.3 无水硫酸锅。3.4 氢氧化钧。3.5硫酸。3.6 磷酸二氢例。3. 7 N，N二乙基-对苯二胶DP3.8 DPD显包邦1:无水硫酸的3. 9 丙二酸溶液(10%)。3. 10 氢氧化创溶液:2mol/L 3. 11 氢氧化纳溶液:0.1mol 3. 12 硫酸溶液:1 mol/L. =91:5:4. SN/T 1954-2007 酸主主氢饵(KH，PO.)加81时_O. 1 mol/L 3. 15 3.
4、16 贼酸押:经120C 140C烘干2人3. 17 膜酸何标准储备溶液称取1.006 g 棋酸仰，溶解于水，转入1000 mL容量瓶中，稀释至刻度，混匀。3. 18 俱酸梆标准使用液z移取1.0 mL膜酸梆标准储备溶液至100mL容量瓶中，稀释至刻度，浓度为10.06 mg/L。4 仪器与设备4. 1 紫外分光光度计。4.2 均质器。4.3 高速冷冻离心机。SN/T 1954-2007 4.4 离心管.50mL。4.5 移液管.1.0 mL、2.0mL、5.0mL、10.0mLo 4.6 具塞比色管.50mLo 5 试样制备与保存5. 1 试样制备从所取全部样品中取出有代表性样品约1I鸣，经
5、捣碎机充分捣碎均匀，均分成两份，分别装人洁净容器内作为试样。密封并加贴标签。5.2 试样保存将试样于18l:以下冷冻保存.在抽样及制样的操作过程中，应防止样品受到污染或发生残留物含量的变化。6 分析步骤6. 1 提取称取试样5.0g(精确至0.1g)于50mL离心管中，加入20mL磷酸盐缓冲液(3.14).提取3mioo 将提取液过滤。残渣再用20mL磷酸盐缓冲液(3.14)重复提取一次，合并滤液，同时做空白试验。将滤液移至50mL离心管中，以10000r/min的转速.4l:于冷冻离心机中离心10min，弃去油脂，以磷酸盐缓冲液(3.14)定容，供分光光度法测定。6.2 测定6.2. 1 标
6、准曲线的绘制向一系列50mL具塞比包管中加入0.00.0.25.0.50.1.50.2. 50.5. 00.10. 00 mL腆酸何标准使用溶液(3.18).各加人1.0g贼化何(3.15).0. 5 mL硫酸(3.12).混匀后静置2min，然后加入0.5mL氢氧化纳溶液(3.10).稀释至刻度.则各管中的浓度相当于0.00.0.05. 0.10. 0.30. 0.50. 1. 00. 2.00 mg汀，的有效氛。分别加入2.5mL磷酸盐缓冲液和1.0g显色剂(3.8).摇匀，立即在2min内用1 cm比色皿在552nm处测定吸光度，绘制标准曲线。6.2.2 样品中二氧化氮的测定取50mL滤
7、液于50mL具塞比色管中，加人1mL丙二酸溶液(3.9)混合，加入1.5 mL磷酸盐缓冲液和1.0 g DPD显色J1!j(3.8)混匀。立即在2min内，用1cm比色皿在552nm处测定吸光度，根据标准曲线求出二氧化氮的浓度.6.3 结果计算2 按式(1)计算试样中二氧化氮残留量:x = (c-co) 0 Vx 1. 9 一z 式中gx 试样中二氧化氮残留量，单位为毫克每千克(mg/kg); c 样液中二氧化氮的浓度，单位为毫克每升(mg/L); Co一一试剂空白中二氧化氮的浓度，单位为毫克每升(mg/L), V一一样液最终定容体积，单位为毫升(mL); m 最终样液所代表的试样质量，单位为
8、克(g);1.9一一二氧化氮与有效氯间的换算系数。( 1 ) 7 测定低限、回收率7. 1 测定低限本方法的测定低限为0.50mg/kg. 7.2 回收率冰鲜鸡肉C102的添加浓度及其回收率实验数据.一一在0.50mg/kg时，回收率为106.O% 114.0% , -一一在2.00mg/kg时，回收率为99.0%103. 0% , -一一在4.00mg/kg时，回收率为97.5%100. 5%。SN/T 1954-2007 3 SN/T 1954-2007 Foreword This standard was proposed by and was under the charge of t
9、he National Regulation Commission for Certification and Accreditation. This standard was drafted by the Jilin Entry-Exit Inspection and Quarantine Bureau of the People 5 Republic of China. This standard was mainly drafte by Xu liming, Zhou Xiao , Chen ty! ingyan , Mu Jun. This standard was a profess
10、ionalsli凶aarlF舌白!fy-exitinspectio占andquarantine promulgated for the first time. / /-4 而P 。-/ 峭fy )./;_; J. Note: This Englisti version. a translation from the Chinese text , is only for reference SN/T 1954-2007 Determination of chlorine dioxide residue in iced meat for import and export -Spectrophot
11、ometric method 1 Scope This standard specifies the method of determination of chlorine dioxide (CIO,) residue in iced meat for import and export by spectrophotometry 2 Principle content of CIO, in iced chicken 3 Reagents and materials AII the reagents used should be 3. 1 Malonic acid. 3. 2 Disodium
12、edetate dihydrate 3.3 Sodium sulphate anhydrous 3.4 Sodium hydroxide. 3. 5 Sulphuric acid 3.6 Potassium dihydrogen phosphate. 3.7 N , N.diethyl-p-phenylenediamine (DPD). 5 SN/T 1954-2007 3.8 DPD color reagent: anhydrous sodium sulphate: DPD: EDTA = 91 : 5 : 4. 3.9 Mal口nicacid aqueous solution (10%)
13、. 3.10 Sodium hydroxide aqueous solution: 2 mofiL. 3.11 Sodium hydroxide aqueous solution: 0.1 moi/L 3.12 Sulfuric acid aqueous soltuion: 1 mol/L. 3.13 Potassium dihydrogen phosphate aqoueous solution: 0.1 mol/L 3.14 Phosphate buffer solution(pH = 6.2): combine 500 mL of O. 1 mol/L KH,PO. with 81 mL
14、 01 0.1 mol/L NaOH , and dilute to 1 000 mL. 3.15 Potassium iodide. 3.16 Potassium iodate: dried 2 h at(120-140)(;. 3.17 Standard stock solution 01 potassium iodate: weigh 1.006 9 potussium iodate. Dissolve with water. Transler to one 1 000 mL 01 calibrated Ilask, dilute to scale with water. Mix tho
15、roughly. 3.18 Standard solution 01 potassium iodate: transler 1. 0 mL 01 the stock standard solution to one 100 mL calibrated Ilask, and dilute to scale. The concentration 01 this standard solution is 10.06 mg/L. 4 Apparatuses and equipments 4. 1 Ultraviolet spectrophotometer. 4.2 Homogenizer. 4.3 H
16、igh speed relrigerated centriluge. 4.4 Centriluge tube: 50 mL 4.5 Graduated pipettes: 1.0 mL, 2.0 mL, 5.0 mL , and 10.0 mL. 4. 6 Stoppered color comparison tubes: 50 mL. 6 SN/T 1954-2007 5 Preparation and storage of test sample 5. 1 Preparation of test sample Approximate 1 kg of representative sampl
17、e is taken from the whole test sample. Grind thoroughly with a grinder. Mix thoroughly and divide into two equal portions as test sample. Put into clean con. tainers. Seal and label them. 5. 2 Storage of test sample The test samples should be frozenly stored below -1日C.Certain measures should be tak
18、en to pre. vent contamination of the samples or decomposition of the residues during the sample preparation procedure. 6 Procedure 6. 1 Extraction Weigh 5.0 g(accurate to O. 1 g)of the test sample into a 50 mL centrifuge tube. Add 20 mL of phos phate buffer solution(3. 14)and extract for 3 min and f
19、ilter the extract. Re-extract the residue with 20 mL phosphate buffer solution (3. 14). Combine the two filtrates. Meanwhile the blank test is run ning. Transfer the combined filtrate to one 50 mL centrifugal tube and centrifuge at 10000 r/min for 10 min at 4C in the high speed refrigerated centrifu
20、ge. Discard oil and fat. Dilute to the scale with phosphate buffer (3. 14) solution for the determination by the spectrophotometer. 6.2 Determination 6.2. 1 Drawing the calibration curve Respectively transfer O. O. 0.25. O. 50. 1.50. 2.50. 5.00. 10.00 mL standard solutions of potassium iodate (3.18)
21、 into 50 mL stoppered colorimetric tubes. Add 1.0 9 potassium iodate (3.1日.0.5mL sulfuric acid (3.12) into each tube. Mix thoroughly. Stand still for 2 min. Then. add O. 5 mL sodium hydroxide solution (3.10). Dilute to scale. The concentrations of effective chlorine in the tubes are 0.00. 0.05. 0.1日
22、.0.30. 0.50. 1.00. 2.mg/L Separately add 2.5 mL phosphate buffer solution and 1. 0 9 color reagent (3. 8). Shake thoroughly. Using 1 cm color comparison cells immediately measure absorbance at 552 nm in 2 min. Draw the calibration curve. SN/T 1954-2007 6.2.2 Determination of CIQ, in the test臼mpleMov
23、e 50 mL of filtrate to one 50 mL of stoppered colorimetric tube. Add 1 mL of malonic acid (3.9). Mix thoroughly. Add 1.5 mL of phosphate buffer solution and 1.0 g of DPD color reagent. Mix thoroughly. Using one 1 cm of colorimetric cell immediately measure the absorbance at 552 nm in 2 min. The conc
24、entration of CIO, is calculated from the value of absorbance according to the cali bration curve. 6.3 Calculation and expression of the result Calculate the content of chlorine dioxide residue in the test sample according to formula( 1) : _ (c - co) V x 1.9 ( 1 ) 口、where X 一theresidue content of chl
25、orine dioxide in the test sample. mg/kg, c-the concentration of chlorine dioxide in the sample solution , mg/L, co-the concentration of chlorine dioxide in the blank solution. mg/L, V一thefinal volume of the sample solution , mL, m-the corresponding mass of the test sample in the final sample solutio
26、n，目;1. 9-the conversion coefficient between chlorine dioxide and effective chlorine 7 Detect limit and recovery 7. 1 Limit of quantification The limit of quantification of this method is 0.50 mg/kg 7.2 Recovery The experimental data of the fortified concentrations of CIO, in blank frozen and fresh chicken and their corresponding recoveries are: Spike O. 50 mgj闹，the recovery 106.0%-114.0%, Spi ke 2. 00 mg/阔，therecovery99.0%-103.0%, Spi ke 4. 00 mg/闸，the recovery 97. 5 % -100. 5 %. SN/T 1954-2007 书号，155066- 2-18236 定价，8元
