【商检行业标准(SN)】 进出口冰鲜肉中二氧化氯残留量的检验方法 分光光度法

中华人民共和国出入境检验检疫行业标准SN/T1954—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 mcat for import and export-Spectrophotometric nmcthod
2007-08-06发布
中华人民共和国
国家质量监督检验检疫总局
数码防件
2008-03-01实施
中华人民共和国出人境检验检疫行业标摊
进出口冰鲜肉中二氧化氛残留量的检验方法分光光度法
SN/T1554—2607
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200:年 11 第一版
宁数16下学
2007年11月第次印别
印数 00
书：155066：2-18236定价8.00元YIKAONTKAca
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胺局。本标推主要起草人：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/T1954—2007
1范围
进出口冰鲜肉中二氧化氯残留量的检验方法
分光光度法
本标准规定了冰鲜肉中二氧化氯残朗量的分光光度检测方法。本标准适用于冰鲜鸡肉中二氧化氮残留量的谢定2方法提要
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SN/T 1954--2007
试样用磷酸盐缓冲溶液提取经冷冻离心+以丙二酸作掩蔽剂，肿人DPD显色剂与二氧化氯显色，采用分光光度法在552nm处测定其数大吸光发炒而米确定冰鲜焱肉中二氧化的含量。试剂和材料
除另有规定外，所用试剂均为分，水为超纯水3. 1 丙二酸。
3.2乙二胺四乙酸二钠（EDTA
3.3无水硫酸钠。
3.4氢氧化钠。
3.5硫酸。
3. 6 磷酸二氢钾。
N,N-二乙基-对苯二胺（DPD）
3.8DPD显色剂：无水硫酸钠：N,N-3.9
内二酸溶液(10%）
氢氧化钠浒液：2mo1/L
氢氧化钠溶液：0.1mo1/
疏酸溶液：1 mol/L。
去基-对苯二胺DPP:EDTA=91：5：4.磷酸二氢钾溶液：0.1molX
磷酸盐缓冲液(pH=6.2);吸500ml,0.1mol/1.的磷酸二钾(KH,PO.)加81mL0.1mo1/L3.14
的氢氧化钠混勾。
碘化钾，
鸦酸钾：经120℃~~140℃烘于2h酸钾标准储备游液：称取1.006g碘酸钾，溶解于水，转入1000mL容量瓶中，稀释至刻度，碘酸钾标准使用液：移取1.0ml.碘酸钾标准储备溶液至100mL容量瓶，稀释至刻度，浓度为10. 06 mg/L..
仪器与设备
紫外分光光度计。
均质器。
4.3商速冷冻离心机。
SN/T 1954—2007
4.4两心管：50mL。
4.5移液管：1.0mL、2.0mL、5.0mL、10.0mL。4.6具塞比色管：50mL。
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1kg，经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。密均并加贴标签。5.2试样保存
将试样于一18℃以下冷冻保存。在拍样及制样的换作过程中，应防止样品受到污染或发生残留物含景的变化。
6分析步骤
6.1.提取
称放试样5.0g（精确至0.1g)于50ml.离心管中，加人20mL磷酸盐缓冲液（3.14)，提取3min。将提取液过滤。残剂再用20ml.磷酸盐缓冲液（3.14)重复提取-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，4℃于冷冻离心机中离心10min，弃去油脂，以避敷盐缓冲波(3.14)定窄，供分光光度法测定。6.2测定
.6.2.1标准曲线的绘制
向一系列50mL具骤比色管中加人0.00,0.25,0.50,1.50,2.50,5.00,10.00mL碘酸钾标准使用溶液（3.18)，各加人1.0g碘化钾（3.15),0.5ml硫酸（3.12).混匀后静罩2min，然后加人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0.00，0.05，0.100.300.50.1.00，2.00mg/L的有效氯。分别加人2.5mL磷酸盐缓冲液和1.0g显色剂（3.8），摇勾，立即在2min内用1cm比色血在552nm处测定吸光度，绘制标准邮线。6.2.2样品中二氧化氯的测定
取50ml.滤液于50mL具塞比色管中，加入1ml丙二酸溶液（3.9）混合，加人1.5mL磷酸盐缓冲没和1.0gDPD显色剂<3.8)混句。立即在2min内，用1cm比色Ⅲ在552nin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
按式(1)计算试样中二氧化氛残留量：X(c-).Vx1.9
式中：
X——试样中二氧化氯残留量，单位为毫克每千克(rng/kg)：一样液中二氧化氯的浓度，单位为毫克每升（tmg/I)；—一试剂空白中二氧化氮的浓度，单位为毫克每升（B/1.)：V——样液最终定容体积,单位为毫升(mL)m
一最终样液所代表的试样质鞋，单位为克（g）)；1.9—-二氧化氯与有效短间的换算系数。2
测定低限、回收率bzxZ.net
7.1测定低限
本方法的测定低限为0.50mg/kg
回收率
冰鲜鸡肉C1O：的添加浓度及其回收率实验数据：在0.50mg/kg时，回收率为106.0%-~114.0%一在2.00mg/kg时，回收率为99.0%~103.0%，一在4.00mg/kg时，回收率为97.5%~100.5%。KAOTKAca-
SN/T1954—2007
S.N/T1954—2007
Foreword
This standard was proposed by and was under the charge of the National Regulation Commission forCertification and Accreditation.This standard was drafted by the Jilin Entry-Exit Inspectior and Quarantine Bureau of the People'sRepublic of China.
This standard was mainly drafted by Xu Liming,Zhou Xiaa, chehen Mingyan, Mu Jun.
This standard was a professionar'standard'for eritfy-exit inspectian and quarantine promulgated forthe first time.
Note: This English version, a translatian fram the Chinese text, is anly for reference.1
HKAONTKAca
SN/T 1954—-2007
Determination of chiorine dioxide residue in iced meatfor import and export -Spectrophotometric methodScope
This standard specifies the method af determination of chlorine dioxide (ClO,) residue in iced meatforimportandexportbyspectrophotometryThis standard is applicable to theldetermination of residual cantent af chlorine dioxide in iced chickenfor import and export.
2 Principle
the phosphate-buffersolution...Jhe extract is refrigeratedly cen+Thetestsamplaisextractedwitb-ttrifugated. Emplay malonic acid as the masking reagent and add color reagent of DPD to take colorreaction with ClO2. Test the maxtmum absorbance at 552 nm by spetrophotometry to determine thecontent of ClOz in iced chicken.3 Reagents and materials
All the reagents used should bea bt anatytical grace unr
3.1Malonic acid.
Disodium edetate dinydrate (EDTA)Sodium sutphate anhydrous
Sadium hydroxide,
Suiphuric acid.
Potassium dihydrogen phosphate.3.6
N,N-diethyl-p-phenylenediamine(DPD)spechfied. .Water is ultra-pure water.SN/T 1954—2007
DPD cofor reagent: anhydrous sodium sulphate:DPD,EDTA= 91 + 5 + 4.Malonic acid aqueaus solution (to%>.Sodium hydroxide aqueous solution: 2 mol/L.Sodium hydroxide aqueous solution: o. t mol/L.Suifuric acid aqueous soltuion: 1 mol/L.3. 13Potassium dihydrogen phosphate aqoueous solution: 0. 1 mol/L.3. 14 Phosphate buffer solution(pH= 6. 2): combine 50o rnL of 0. 1 mol/L KH2PO with 81 mL ofD. 1 mol/L NaOH, and dilute to 1 000 mL.3.15
Patassium iodide.
3. 16Potassium iodate: dried 2 h at(120~~140) ℃.Standard stock solution of patassium iodate: weigh 1. o06 g potussium iodate. Dissolve with3. 17
water, Transfer to ane 1 ooo mL of calibrated flask, dilute to scale with water. Mix tharoughlyStandard solution of potassium iodate: transfer 1.0 mL of the stock standard solution to3.18
one 1oo mL calibrated flask, and dilute to scale. The concentration of this standard solutionIs 10.06 mg/L.
4 Apparatuses and equipments4.1
Ultraviolet spectrophotometer.Homogenizer.
High speed refrigerated centrifuge.Centrifuge tube: 50 mL
Graduated pipettes: 1. 0 mL. 2. 0 mL, 5.0 mL, and 10. Q mL.4.5
4.6Stopperedcolorcomparisontubes：50mL6
5Preparation and storage of test sarmple5.1Preparation af test sampifeKAoiKAca
SN/T 1954—2007
Approximate 1 kg of representative sample is taken from the whole test sample. Grind thoraughlywith a grinder. Mix thoroughly and divide into two equal portions as test sampte. Put into clean can-tainers. Seal and label them.5. 2Storage of test sample
The test samples should bs frozenly stored below -18'C. Certain measures should be taken to pre-vent contamination of the samples or decomposition of the residues during the sample preparationprocedure.
6 Procedure
6. 1Extraction
Weigh 5. 0 g(accurate to 0. 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 filter the extract. Re-extract the residue with20 mL phosphate buffer solution (3. 14). Combine the two filtrates. Meanwhile the blank test is run-ning. Transfer the combined fitrate to one 50 mL centrifugal tube and centrifuge at 10 o00 r/min for10 min at 4'c in the high speed refrigerated centrifuge. Discard oil and fat. Dilute to the scale withphosphate buffer (3. 14) solution for the determination by the spectrophotometer.6.2Determinatian
6,2. 1Drawing the catibration curveRespectively transfer 0.0.0.25.0.50,1.50,2.50,5.00,1D.00mL standard solutions of potassiumiadate (3. 18) into 50 mL stoppered colorimetric tubes. Add 1.0 g potassium iodate (3. 15), 0. 5 mLsulfuric acid (3.12) into each tube. Mix thoroughly.Stand stilt for 2 min. Then,add o.5 mL sodiumhydroxide solution (3. 1o). Dilute to scale. The concentratians of effective chlorine in the tubes are0.00,0.05.0.10,0.30,0.50,1.00,2.00 mg/LSeparately add 2, 5 mL phosphate buffer solution and 1. 0 g color reagent (3, 8), Shake thoroughly.Using1 cm color comparison cells immediatelymeasureabsorbance at 552nm in2min.Draw thecalibration curve.
SN/T 1954—2007
6. 2. 2 Determinatian ot ClO, in the test sampleMove 50 ml of filtrate to one 50 mL of stoppered colorimetric tube. Add 1 mL of mafonic 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 af colorimetric cell immediately measure the absorbance at 552 nmin 2 min. The concentration of Clo, is calculated from the value af absorbance according to the cali-bration curve.
6, 3 Calculation and expression of the resultCaiculate the content of chlorine dioxide residue in the test sample accarding to formula1) :X = (c- co) . V× 1.g
X---the residue content of chlorine dioxide in the test sample, mg/kg :c-the concentration of chlorine dioxide in the sample solution, mg/L,Cathe concentration of chlorine dioxide in the blank solution, mg/L:V-the tinal volume of the sample solution, ml.;m-the corresponding mass of the test sampie in the final sample solution, g.1. 9 --the conversion coefficient between chlorine dioxide and effective chlorine.7Detect limit and recovery
7. 1 Limit of quantificationThe limit of quantification of this method is0.50mg/kg7.2Recovery
The experimental data of the fartified concentrations of CiO, in blank frozen and fresh chicken andtheir corresponding recoveries are:Spike0.50mg/kg.therecovery106.0%~114.0%;-Spike 2. 00 mg/ kg, the recovery 99. 0% ~103. 0% +Spike 4.00 mg/kg,the recovery97.5%~100.5%.号：1550662-18236
SN/T1954-2007
定价：
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