1、s 中华人民共和国出入境检验检疫行业标准SN/T 3927-2014 出口乳制品中硫氨酸锅含量的测定Determination of sodium thiocyanate in dairy products for export 2014-04-09发布2014-11-01实施A饥码呈1、.t飞跑协 网站lw315.oom电话凶98315由l涂层查真伪中华人民共和国发布国家质量监督检验检疫总局中华人民共和国出入境检验检疫行业标准出口乳制晶中疏霞酸铀含量的测定SN/T 3927 2014 争e中国标准出版社出版北京市朝阳区和平里西街甲2号(100029)北京市西城区三里河北街16号(10004日
2、总编室，（010)68533533网址中国标准出版社秦皇岛印刷厂印刷9峰开本88012301/16 印张1.75字数45千字2014年12月第一版2014年12月第一次印刷印数1-1300 头书号：155066 2-27674 定价27.00元SN/T 3927-2014 前言本标准按照GB/T1.1 2009给出的规则起草。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：中华人民共和国山东出入境检验检疫局、中华人民共和国山西出入境检验检疫局、湖南省检验检疫科学技术研究院。本标准主要起草人：胡巧茹、杨丽君、王静、杜利君、崔凤杰、宋晓华、丛伟红、刘玉敏、付英文、崔鹤、瞿金义、赵悠悠
3、、刘红艳、姚亚婷、黄志强。I SN/T 3927-2014 出口乳制晶中硫氨酸纳含量的测定1 范围本标准规定了出口乳制品中硫氨酸铀含量的离子色谱测定方法和气相色谱测定方法。本标准适用于灭菌乳、杀菌乳、酸牛乳、配方乳、乳饮料、乳粉、配方乳粉、干醋、炼乳等乳制品中硫氨酸铀含量的测定。2 规范性引用文件下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本（包括所有的修改单）适用于本文件。GB/T 6682 分析实验室用水规格和试验方法第一法离子色谱法3 原理试样中硫氨酸根经乙睛提取、沉淀蛋白后，对提取液进行净化，以氢氧化饵榕液为淋
4、搅液，阴离子交换柱分离，电导检测器检测。以保留时间定性，外标法定量。4 试剂和材料除另有规定外，所用试剂均为分析纯，试验用水符合GB/T6682中一级水的规定。4. 1 硫氨酸铀标准物质（sodiumthiocyanate，分子式：NaSCN,CAS编号：540-72-7）：纯度注99.99%。4.2 乙睛CCH3CN）：色谱纯。4.3 甲醇（CHaOH）：色谱纯。4.4 硫氨酸铀（以硫氨酸根计）标准储备液（1 000 mg/L) ：准确称取0.1397 g硫氨酸铀，用水定容至100 rnL在04冰箱中保存，有效期为6个月。4.5 硫氨酸铀（以硫氨酸根计）标准中间液(10mg/L）：准确移取硫
5、氨酸铀标准储备液（4.4)1.00mL于100 mL容量瓶中，用水稀释至刻度，摇匀。在04冰箱中保存，有效期为1个月。4.6 尼龙滤膜：0.22m。4.7 RP柱（1.0mL），或性能相当的能去除有机物质的前处理小柱，使用前依次用5mL甲醇、10mL 水活化，放置30min后使用。5 仪器和设备5. 1 离子色谱仪：配电导检测器。5.2 离心机：转速不低于6000 r/mino 5.3 涡旋混匀器。1 SN/T 3927-2014 5.4 分析天平：感量0.1mg、0.01g. 5.5 离心管：15mL. 6 试样制备与保存从所有样品中取出有代表性样品约500g或500mL，将样品充分渥匀，均
6、分成两份，分别装人洁净容器中，密封，并标明标记，于04条件下保存。7 分析步骤7.1 试样处理7. 1. 1 灭菌乳等液体样品z称取4g（精确至0.01g）样品，用乙腊（4.2）定容至10mL(V1），转移至离心管中，涡旋混匀2min，室温静置沉降蛋白20min，以6000 r/min转速离心10min.准确移取上层清液1.00 mL(V2），用水定容至10mL(Va）并混匀。取上述溶液适量，依次过0.22m尼龙滤膜、RP柱或性能相当者，弃去前3mL滤液，收集后面谑液供离子色谱仪测定。可根据样品中硫氧酸根含量情况，用水适当稀释待测样品溶液。7.1.2 乳粉等固体样品z称取1g（精确至0.01g
7、）样品，加入4g水，立即摇匀，涡旋混匀2min，用乙睛(4.2）定容至10mL(V1），混匀后转移至离心管中，室温静置沉降蛋白20min，以6000 r/min转速离心10 min.准确移取上层清液1.00mL(V2），用水定容至10mL(Va）并温匀。取上述溶液适量，依次过0.22 m尼龙滤膜、RP柱或性能相当者，弃去前3mL滤液，收集后面滤液供离子色谱仪测定。可根据样品中硫氨酸根含量情况，用水适当稀释待测样品溶液。7.2 色谱分析参考条件7.2.1 色谱柱z氢氧化物选择性、疏水性低且可兼容梯度洗脱的高容量阴离子交换柱，如IonPac AS 16型分析柱，4mm 250 mm（配备IonPa
8、c AG 16型保护柱4mm 50 mm），或性能相当的离子色谱柱。7.2.2 柱温箱温度：30。7.2.3 淋洗液z氢氧化饵溶液，浓度为45mmol/L 60 mmol/L，梯度淋洗，淋洗液OH一浓度见表L表1琳洗灌OH浓度表时间流速OH浓度mm mL/min mmoL/L o.oo 13.00 1.00 45.0 13.0018.。1.00 60.0 18.00 23.00 1.00 45.0 7.2.4 抑制器：ASRS-300 4 mm阴离子抑制器，或选用其他具有相同功能的抑制器z外加水抑制模式，抑制电流112mA 149 mA，外加水流量1.5mL/min. 7.2.5 淋洗液流速：
9、1.0mL/min。7.2.6 进样体积：100L。7.2.7 检测器z电导检测器。SN/T 3927-2014 7.3 绘制标准曲线取硫氨酸铀标准中间液（4.5），根据需要用水稀释制取系列标准工作榕液（参考线性范围为0.01 mg/L 1.00 mg/L），按色谱分析条件（7.2），由低到高浓度依次进样测定。根据所得色谱图，以硫氨酸铀（以硫氨酸根计）的浓度为横坐标、以峰面积（或峰高）响应值为纵坐标，绘制标准曲线，并计算线性回归方程。典型离子色谱图参见附录A中的图A.1。7.4 样晶分析将测试榕液按色谱分析条件（7.2）进行测定，记录色谱图。根据硫氯酸根保留时间定性，测量测试榕液中的硫氨酸根的
10、峰面积（或峰高响应值，采用外标法定量。测试溶液中硫氨酸根的响应值应在标准线性范围内。7.5 空白试验除不称取试样外，其余均按上述步骤进行。8 结果计算试样中硫氨酸铀（以硫氨酸根计）的含量按式(1）计算zX (c -co) Y1 Ya 1 000 m Y2 1 000 式中zX一一试样中硫氨酸铀（以硫氨酸根计）的含量，单位为毫克每千克（mg/kg);c 测试榕液中硫氨酸铀（以硫氨酸根计）的浓度，单位为毫克每升（mg/L);Co一一空白溶液中硫氯酸铀（以硫氨酸根计）的浓度，单位为毫克每升（mg/L);Y1一一样品用乙腊提取时定容体积，单位为毫升（mL);Ya一一提取被用水稀释时定容体积，单位为毫升
11、（mL);m 试样质量，单位为克（g);Y2一一用水稀释时移取提取液的体积，单位为毫升（mL）。计算结果保留至小数点后两位。9 测定低限. ( 1 ) 本方法对乳制品中硫氨酸铀（以硫氨酸根计）含量的测定，灭菌乳等液态样品测定低限为0.25mg峙，乳粉等固态样品测定低限为1.00mg/kgo 10 回收率与精密度样品添加回收率及精密度试验数据参见附录B中的表B.1。第二法气相色谱法11 原理试样中硫氨酸根经水提取后，加入氯胶T将硫氨酸根转变为氯化钮，顶空进样，气相色谱法检测，SN/T 3927-2014 外标法定量。12 试剂和材料除另有规定外，所用试剂均为分析纯，试验用水符合GB/T6682中
12、一级水的规定。12.1 硫氧酸铀标准品（sodiumthiocyanate，分子式：NaSCN,CAS编号：540-72-7）：纯度二三99.99%。12.2 乙酸辞。12.3 氯胶T：保存于干燥器中。12.4 乙酸辞溶液：称取22g乙酸铮(12.2），榕于水中，并稀释定容于100mL。12.5 氯肢T溶液：称取1g氯胶TC12.3），榕于水中，并稀释定容于100mL。12.6 硫氨酸铀（以硫氨酸根计）标准储备洛液(1000 mg/L) ：准确称取0.1397g硫氨酸铀，用水定容至100 mL。在04。C冰箱中保存，有效期6个月。12.7 硫氨酸铀（以硫氨酸根计）标准中间溶液(10mg/L）：
13、准确移取1.00mL的硫氨酸铀标准储备榕被(12.6）于100mL的容量瓶，用水稀释至刻度。在04冰箱中保存，有效期1个月。12.8硫氨酸铀（以硫氨酸根计）标准工作洛液：移取适量标准中间溶液(12.7）用水稀释为浓度0、0.005、0.01、0.02、0.05、0.1mg/L的标准工作榕液。13 仪器与设备13. 1 气相色谱：配电子捕获检测器CECD）。13.2 顶空进样器。13.3 顶空瓶：20mL。13.4 涡旋混匀器。13.5 分析天平：感量0.0001 g、0.01g0 13.6 离心机：转速不低于4000 r/mino 14 试样制备与保存从所有样品中取出有代表性样品约500g或5
14、00mL，将样品充分混匀，均分成两份，分别装入洁净容器中，密封，并标明标记，于04条件下保存。15 测定步骤15. 1 试样处理称取试样1g（精确至0.01g），加入4mL乙酸悻榕液(12.4），用水定容至100mL，放置1h后，以4 000 r/min转速离心5min。准确移取10mL上清液于顶空瓶中，加入0.1mL氯胶T洛液(12.5），立即加盖密封，涡流混合，待测。15.2 色谱分析参考条件15.2. 1 顶空分析条件参见附录C。15.2.2 气相色谱条件如下：a) 色谱柱：BPlO毛细管柱，25m 0.32 mm（内径）0.50m（膜厚），或性能相当者；b) 色谱柱温度：40保持5mi
15、n，以50min速率升至200C保持2min; 4 SN/T 3927-2014 c) 载气：氮气，纯度不低于99.999%;d) 进样口温度：150；e) 检测器温度：260；f) 分流比：100: 1; g) 柱流速：1.0mL/min。15.3 标准曲线绘制准确移取10mL标准工作液(12.8）于顶空瓶中，分别加入0.1mL氯胶T溶液，立即加盖密封，涡流混合，待测。按色谱分析条件(15.Z），由低到高浓度依次进样测定。根据所得色谱图，以硫氨酸铀（以硫氨酸根计）的浓度为横坐标、以峰面积（或峰高）响应值为纵坐标，绘制标准曲线，并计算线性回归方程。在上述色谱条件下，硫氨酸根离子衍生物的保留时间
16、约为Z.50min，典型色谱图参见附录A中的图A.Z。15.4 样品分析将测试溶液按色谱分析条件(15.Z）进行测定，记录色谱图。根据硫氨酸根离子衍生物保留时间定性，测量测试溶液中硫氧酸根离子衍生物的峰面积或峰高）响应值，采用外标法定量。测试溶液中硫氨酸根离子衍生物的响应值应在标准线性范围内。15.5 空白试验除不称取试样外，其余均按上述步骤进行。15.6 结果计算和表述试样中硫氨酸铀（以硫氨酸根计）的含量按式（2）计算zX一（c- co ) V 1 000 - m i 000 式中：x 试样中硫氨酸铀（以硫氨酸根计）的含量，单位为毫克每千克（mg/kg);c 测试溶液中硫氨酸铀（以硫氨酸根叶
17、的辙度单位为毫克每升（mg/L);Co一一一空白洛液中硫氨酸铀（以硫氧酸根计的浓度，单位为毫克每升（mg/L);V一一样液定容体积，单位为毫升（mL);m 样品质量，单位为克（g）。计算结果保留至小数点后一位。16 测定低限本方法对乳制品中硫氨酸铀（以硫氨酸根计）的测定低限为1.0mg/kg。17 回收率与精密度样品添加回收率及精密度实验数据参见附录B中的表B.Zo. ( z ) 5 SN/T 3927-2014 附录（资料性附录）标准溶液色谱图A 4.00 3.50 的Lhm同时，EgomH3.00 的2.50:t 、理组2.00 1. 50 1. 00 0.50 23. 0 t/min 2
18、0.0 15. 0 10.0 5.0 -0.00 -0.50 0. 0 磕鲁在酸铀（以畸篝酸根计）标准溶液的离子色谱图（1mg/L) 图A.16 SN/T 3927-2014 (10) 1. 75 1. 50 1. 25 1. 00 、:t 、CNCl 量。75誓0. 50 0.25 0.00 .-1 二 0. 5 1. 0 1. 5 2.0 2.5 3.0 3.5 4.0 4.5 t/min 图A.2畸霞酸铀（以硫鲁在酸根计）离子衍生物的气相色谱圄（0.01mg/L) 7 SN/T 3927-2014 附录B（资料性附录）样晶添加回收率与精密度实验数据表表B.1样晶添加回收率与精密度实验数据
19、表（离子色谱法）硫氨酸销（以硫氨酸根计）回收率范围相对标准偏差样品名称添加浓度% % mg/kg 0.25 80.4 100.2 6.45 灭菌乳0.50 92.3 104.1 4.89 2.50 93.2 101.2 2.99 0.25 88.6 105.5 6.31 杀菌乳0.50 88.9 105.8 5.43 2.50 90.6 103.8 4.61 0.25 88.3 104.4 5.35 酸牛乳0.50 92.8 106.0 4.83 2.50 90.4 101.2 4.15 0.25 87.5 105.1 7.78 配方乳0.50 88.2 104.1 7.74 2.50 90.
20、8 104.4 4.74 0.25 86.l 108.7 8.36 军L饮料0.50 86.6 104.2 6.94 2.50 91.6 102.8 3. 70 1.00 90.4 105.6 5.59 乳粉2.00 91.3 103.3 4.84 10.00 91.8 102. 7 3.90 1.00 91. 7 104.3 4. 73 配方乳粉2.00 92.1 98.5 2.57 10.00 92.1 103. 7 3.95 1.00 90.9 102.6 4.31 干酶2.00 91.5 105. 7 5.08 10.00 95.2 104.5 3.31 1.00 91.1 104.7
21、 4.58 炼乳2.00 93.l 105.5 4.24 10.00 92.2 103.9 4.72 8 SN/T 3927-2014 表B.2样品添加回收率与精密度实验数据表（气中目色谱法）硫氨酸饷（以硫氨酸根计）回收率范围相对标准偏差样品名称添加浓度% % mg/kg 1.0 94.0 1 10.。5.36 杀菌乳2.0 90.5 108.5 5.60 10.0 90.2 107.3 7.49 1.0 90.0110.。6.86 酸牛乳2.0 90.5 108.5 6. 78 10.0 90.l 107.2 6.22 1.0 91.0109.。6.86 乳粉2.0 91.5 106.5 5
22、.07 10.0 90.4 109.1 7.39 1.0 91.0110.。7.53 乳饮料2.0 90.5 108.5 7.37 10.0 93.1 109.3 4.98 1.0 93.0110.。5.47 干酶2.0 94.5 108.5 3.91 10.0 90.2 109.3 7.89 1.0 92.0 109.0 5.92 配方乳2.0 93.5110.。6.30 10.0 92.1 108.4 5.42 9 SN/T 3927-2014 顶空分析条件如下：a) 顶空平衡温度：35；b) 取样针温度：110；c) 传输线温度：120；d) 顶空加热时间：20min; e) 进样时间：
23、0.03min; f) 加压时间：2.5min; 附录C（资料性附录）顶空进样分析条件1)g) 载气：12.5psi(l psi=6.895 kPa）。1) 非商业性声明：附录C所列的顶空进样分析条件是在PETurboMatrix 16型顶空进样器上完成的，此处列出试验用仪器型号仅为提供参考，并不涉及商业目的，鼓励标准使用者尝试不同厂家或型号的仪器。10 SN/T 3927-2014 Foreword The standard are compiled accodingas the GB/T 1.1-2009. The standard was proposed by and is undet
24、hecharge of the Certification and AceeditationAdmin istration of the People s Republic of China. The standard was drafted by Shandong Entry-Exit Inspection and Quarantine Bureau of the Peoples Republic of China, Shanxi Entry-Exit Inspection and Quarantine Bureau of the Peoples Republic of China, Hun
25、an Academy of Inspection and Quarantine. The standard was mainldrafted by Hu Qiaoru, Yang Lijun, Wang Jing, Dulijun, Cui Fengjie, Song Xiaohua,Cong Weihong,Liu Yumin,Fu Yingw町，CuiHe,Zhai Jinyi,Zhao Youyou,Liu Hongyan, Yao Yating, Huang zhiqiang. 11 SN/T 3927-2014 Determination of sodium thiocyanate
26、in dairy products for export 1 Scope This standard specifies the ion chromatographic method and gas chromatographic method for the de” termination of sodium thiocanate in dairy products of export. This standard is applicable to the determination of sodium thiocyanate in sterilized milk, pasteurized
27、milk, yoghurt, formula milk, milk beverage,milk powder, formula milk powder, cheese and condensed milk of export. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated refere
28、nces, the latest edition of the ref erenced document (including any amendments) applies. GB/T 6682 Water for analytical laboratory use-Specification and test method Ion chromatography 3 Principle The sample was extracted and precipitated protein with acetonitrile, then the extract was cleaned, separ
29、ated by anion exchange column, potassium hdroxide solution as eluent. The determination was aceieved by ion chromatography equipped with conductance detector,qualitatified with the retention time and quantified by external standard method. 4 Reagents and materials Unless otherwise specified, the rea
30、gents used should be analytical pure. And the water should comply with the requiementof GB/T 6682 (first class water). 4.1 Sodium thiocyanate standard (NaSCN, CAS No.: 540-72-7): purity注99.99%.12 SN/T 3927-2014 4.2 Acetonitri le C CH3 CN) : HPLC grade. 4.3 Methanol CCH30H): HPLC grade. 4.4 Sodium th
31、iocyanate CSCN ) standard storage solution (1 000 mg/L): accurately weigh sodium thiocanate 0.139 7 g,then transfer it into 100 ml volumetric flask,dillute to mark with wate.Pre serve at O4for six month. 4.5 Sodium thiocyanate C SCN- ) standard work solution C 10 mg/L) : according to need, accuratel
32、y pipette sodium thiocyanate standard storage solution (4.4) 1.00 ml into 100 ml volumetric flask dil lute to mark with wate.Preserve at 04for one month. 4.6 0ganicneedle filter membrane:0.22 m. 4. 7 OnGuard II RP column C 1. 0 ml) : activation with 5 ml methanol, 10 ml water, standing for 30 min. 5
33、 Apparatus and equipment 5.1 Ion chromatography: equipped with conductance detector. 5.2 Centifuge：注6000min.5.3 Vortex mixer. 5.4 Balance: with 0.01 g and 0.000 1 g sensivity. 5.5 Color comparison tube with cap: 15 ml. 6 Sample preparation and storage Collect a 500 g or 500 ml sample that is represe
34、ntative of the entire sample. The sample should be mixed directly and divided into two equal portions. Each potionis placed into a clean vessel as a test sample, which is then sealed. All the samples should be stored undeO47 Analytical procedure 7 .1 Sample pretreatment 7 .1.1 Liquid Samples Accurat
35、ely weigh 4.0 g test sample (accurate to 0.01 g) into a color comparison tube with cap,dillute to 10 ml C机）with acetonitrile. Shake it on the votexmixefo2min, stand for 20 min to precipi-13 SN/T 3927一2014tate protein at room temperature and then centrifuge at 6 000 r/min for 10 min. Accurately pipet
36、te 1.0 ml CVof the supernatant into a color comparison tube with cap, dillute to 10 ml ( V3) with water, shake it on the vortex mixer and take the extract to filter through a 0.22 m membrane, then cleaned by SPE column(for example Guard II RP colum时，discardthe first 3 ml of solution and take the mid
37、dle section of the filtrate for Ion chromatography determination. If the sodium thiocanate exceeds the range of the standard curve, the sample amount should be reduced or the multiple shmIdbe increased. 7.1.2 Solid sample Accurately weigh 1.0 g test sample (accurate to 0.01 g) into a color compariso
38、n tube with cap, add 4 g water and shake it on the vortex mixer for 2 min, then dillute to 10 ml( V, )with acetonitrile. Mix it well on the vortex, then stand for 20 min to precipitate prettied at room temperature and then cen trifLgeat 6 000 r/min for 10 min. Accurately pipette 1.0 ml ( V2) of the
39、supernatant into a color comparison tube with cap,dillute to 10 ml ( V3) with water, shake it on the vortex mixer and take the extract to filter through a 0.22 m membrane, then cleaned by SPE column(for example Guard II RP column), discard the first 3 ml of solution and take the middle section of th
40、e filtrate for Ion chro matographdetermination. If the sodium thiocyanate exceeds the range of the standard curve, the sample amount shmIdbe reduced or the multiple should be increased. 7.2 Chromatography operating conditions 7 .2.1 Chromatography column: hydroxide selective, high臼pacityanion exchan
41、ge column compatible with gradient elution,for example Ion Pac AS 16,4 mm 250 mm (with Ion Pac AG 16, 4 mm 50 mm guard column). 7 .2.2 The temperature of column: 30 7.2.3 Eluent: potassium hydroxide solution, the concentration of 45 mmol/L60 mmol/L,utilizing a gradient elution program (0.00 min 13.0
42、0 min,45.0 mmol/L; 13.00 min 18.00 min,60.0 mmol/L; 18.00 min23.00 min ,45.0 mmol/L). 7 .2.4 Suppressor: ASRS-300 4 mm anion suppressor; external water suppression mode (flow rate: 1.5 ml/mi时，suppressioncurrent is 112 mA149 mA. 7.2.5 Flow rate: 1.0 ml/min. 7.2.6 Injection volume: 100 L. 7 .2. 7 Dete
43、ctor: conductance detector. 7 .3 Standard curve According to need, dilute sodium thiocyanate ( SCN- ) standard work solution with water step b step,and prepare serial standard work soltion of applicable concentrations (referred linear range: 14 SN/T 3927-2014 0.01 mg/L1.0 mg/L). The standard solutio
44、n is determined accodingto chomatographyoperating conditions (7.2). Based on the chromatogram, draw the standard curve with the concentration of sul fur dioxide as abscissa and the response of the peak area (or peak high) as ordinate, and calculate the linear egressionequation. For chromatogram of t
45、he standard see Figure A. 1 is showed in Annex A. 7 .4 Sample analysis The sample solution is deteminedaccording to chromatography operating conditions (7.2), and the quantitative analysis is conducted on the basis of peak area C or peak high) with external standard method. The response value of the
46、 sample solution should be within the range of standard linearity. 7 .5 Blank test The operation of the blank test is the same as the described in the method of determination, but with the omission of sample addition. 8 Calculation and result presentation The content of sodium thiocyanate CSCN ) in
47、the test sample is calculated by Formula (1): nu- nu- nu- 4.,- -o -nu 比一0-aE 一-VHeadspace sampler operating conditions are as follows: a) Temperature of headspace balance:35 C; b) Temperature of sample needle: 110； c) Temperature of transmission line: 120； d) Time of headspace heating:20 min; e) Tim
48、e of sampling:0.03 min; f) Time of pressurize:2.5 min; g) Carrier gas: 12.5 psi C 1 psi= 6.895 kPa). 1) Non-commercial statement, The parameters of Annex Care acquired from PE Turbo Matrix 16 and only are used for reference. The equipments and their types involved in the standard method are not related to commercial aims,and it is encouagedto use equipments of different corporation or different ty阳书号：155066 2 2767 4 SNIT 3927-2014 定价227;00元
