SNT 1774-2006 进出口茶叶中八氯二丙醚残留量检测方法 气相色谱法

1、SNT 1774-2006 进出口茶叶中八氯二丙醚残留量检测方法 气相色谱法s 中华人民共和国出入境检验检疫行业标准SN/T 1774-2006 进出口茶叶中八氯二丙酿残留量检测方法气相色谱法Determination of Octachlorodipropyl ether residue in tea for import and export-Gas chromatographic method 2006-04-25 发布 2006-11-15 实施j黠 中华人民共和国发布海号 国家质量监督检验检痊总局? .bzfxw4 ?前言本标准的附录 A 为资料性附录.本标准由国家认证认可监督管理委

2、员会提出并归口。本标准起草单位 s 中华人民共和国浙江出入境检验检疫局。本标准主要起草人s丁慧瑛、谢文、章晓氨、蒋晓英、曾若雪。本标准系首次发布的出入境检验检疫行业标准。SN/T 1774-2006 I 1 范围进出口茶叶中八氯二丙酷残留量检测方法气相色谱法SN/T 1774-2006 本标准规定了迸出口茶叶中八氯二丙隧残留量测定的制样和气相色谱测定方法。本标准适用于迸出口茶叶中八氯二丙隧残留量的测定。2 $IJ样将全部样品充分拌匀，磨碎，通过孔径为 0.85mm 的筛 (20 目) ，均分成两份，装入洁净的容器肉，作为试祥。密封，并标明标记。在制样的操作过程中，应防止样品受到污染或发生残留物

3、含量的变化。将试样室温保存。3 测定方法3. 1 方法提要样品中的八氯二丙隧残留用丙朋和水提取，再经正己烧反萃取，然后用浓硫酸磺化净化，用配有电子俘获检测器的气相包谱仪测定，外标法定量。3.2 试剂和材料除另有规定外，所用试剂均为分析纯，水为蒸馆水。3.2. 1 正己烧=色i昔纯。3.2.2 丙酣 2色谱纯。3.2.3 氯化纳水溶液， 150 g/L. 3.2.4 浓硫酸。3.2.5 元水硫酸纳， 650C灼烧 4 h，在干燥器冷却至室温，储于密封瓶中备用。3.2.6 八氯二丙隧标准品 z纯度大于 99% 。3.2.7 八氯二丙隧标准储备溶液 z称取 0.01000g 八氯二丙酷标准品 (3.

4、2. 们，用正己烧溶解定容至100 mL，此溶液浓度为 100g/mL。存放在 4C的冰箱中。根据需要用正己炕稀释至适当浓度的标准工作液。3.3 仪器和设备3.3. 1 气相色谱仪，配有电子俘获检测器。3.3.2 旋转蒸发器。3.3.3 均质器。3.3.4 元水硫酸纳柱， 80 mmX40 mm(内径)筒型漏斗，底部垫约 5mm 高脱脂棉，再装约 50 mm 高元水硫酸纳(3.2.5) 。3.4 测定步骤3.4. 1 提取称取 3g试样(精确到 0.01 g)置于 100 mL 烧杯中，加人 10 mL水浸泡 2 h，加入 20 mL 丙丽，在均质器中均质 2 min。过滤至预先装有 50 m

5、L 氯化讷水溶液(3.2.3) 和 20 mL 正己饶的 250 mL 分液漏斗中，用 10 mL 左右丙酬清洗残渣，合并滤液。剧烈振摇，静置分层。分离正己炕相。水相中再加入20 mL正己烧，重复操作，合并正己烧相，过无水硫酸饷柱 (3. 3. 4)至浓缩瓶中，用少量正己烧清洗此柱，? .bzfxw ?SN/T 1774-2006 用旋转蒸发器在 45C 以下水浴减压浓缩至近干。3.4.2 净化浓缩瓶中残留物用 2 mL 正己统溶解，转移入离心管中，浓缩瓶中再加 2 mL 正己饶，重复操作一次。氮气吹干，准确加入 3.0 mL 正己烧，0.5 mL 浓硫酸。振摇，以4000 r/min离心 2

6、 min，用尖嘴吸管吸取下层，弃去。正己烧层再加入 0.5 mL 浓硫酸，重复操作，直到正己烧层元色。正己烧溶液供 GC测定。3.4.3 测定3.4.3. 1 色谱条件 ! a) 色i苦柱 z石英毛细管柱，DB.1 30 mXO.25 mm(直径) XO. 25m(膜厚) ，或相当者 pb) 载气和尾吹气 2氮气(纯度大于 99.999%)，载气流量 z1. 0 mL1m!扣n，尾吹气流量 :30 口mL/口ml让tn盯; C 柱协温配g 初酣始温础度 7附白代保附持 1川mi川n9d) 进样口温度 :20OC句3 e) 检测器温度 :300 l:，。 进样方式 z不分流进样;g) 开阀时间

7、:1 min; h) 进样量: 1L ， 3.4.3.2 色谱测定根据样液中八氯二丙磁含量的情况选定浓度相近的标准工作溶液.唁标准工作溶液和祥液中的八氯二丙腿响应值应在仪器检测的线性范围内。标准工作溶液和样液等体平穿插进样测定。人氯二丙磁标准品的气相色谱图参见附录 A 中图 A.L3.4.3.3 空白试验 &一 一 句 ? J 除不加试样外，均按上述操作步骤进行.在满足试剂纯度、仪器工作和实验环境正常条件下，空白试验应无干扰峰出现。3.4.3.4 结果计算和表述用色谱数据处理机或按式(1)汁算试样中八氯二丙酷的残留含量 zX A.XcXV - AsXm 式中: 剧, ) l ( itH

8、崎咽-1K疆等tpavdz，、aEZ，aEZEBV、-t、民也电aiJJhf飞飞，MefX 试样中八氯二丙隘的残留景，单位为毫克每千克(mg/kg) ; A一一样液中八氯二丙酷的峰面积3As一一标准工作液中八氯二丙酷的峰面积 IC 标准王作液八氯二丙隘的浓度，单位为微克每毫升g/mL) ; V 样液最终定容体积，单位为毫升(mL) , m一一最终样液所代表的试样质量，单位为克(g) 。4 测定低限和回收率4. 1 测定低限本方法的测定低限为 0.01 mg/kg; 卢4.2 回收率囚收率的实验数据如下=一一八氯二丙磁添加浓度在 0.01 mg/kg 时，回收率为 90%114%;一一八氯二丙隧

9、添加浓度在 0.02 mg/kg 时，回收率为 97%108%;八氯二丙隧添加浓度在 0.20 mg/kg 时，回收率为 91%110% 。J / / / 2 。+ T 6 T士10 八氯二丙酷的保留时间约为 15.4 min. 图 A.1J ? 一一SN/T 1774-2006 附录 A (资料性附录)标准晶色i昔圈咱晶费彗 IL-JA/ 斗/F 氯二丙号标准晶气相色谱图/卢/ / / ，r-飞气, 飞L I I / / / ,/ 3 ? .bzfxw ?SNjT 1774-2006 Foreword Annex A of. this standard is an informative a

10、nnex. This standard was proposed by and is under the charged of The Certification and Accreditation Ad-ministration of the Peoples Republic of China. This standard was drafted by Zhejiang Entry - Exit Inspection and Quarantine Bureau. The standard was mainly drafted by Ding Huiying , Xie Wen , Zhang

11、 XiaoDong , Jiang XiaoYing , Zeng Ruo Xue. This standard is a professional standard for entry-exit inspection and quarantine promulgated for the first time. 4 SN/T 1774-2006 Determination of OctachlorodipropI ether residue in tea for import and export-Gas chromatographic method 1 Scope This standard

12、 specifies the methods of sample reparation and determination by gas chromatography (GC) of octachlorodipropyl ether residue in tea for export and import. This standard is applicable to the determination of octachlorodipropyl ether residues in tea for export and import 2 Preparation of test sample T

13、he mixed primary sample is crushed with a grinder or mortar until throughly crushed and wholly passed through a O. 85 mm( id) sieve (20 mesh) , and then divided into two equal portions. Each por-tion is placed in a clean container as the test sample , which is then sealed and labled. In the course o

14、f sampling and sample preparation ，口re臼ut旧ns must be taken to avoid contamination or any factors which may cause the change of residue content. The test samples should be stored at roo盯1 temperature. 3 Method of determination 3. 1 Principle octachlorodipropyl ether residue are extracted from the tea

15、 sample by acetone , and re-extracted by hexane, and cleaned up with sulfuric acid. The solution is used for GC-ECD determination. External standard method is used for quantitative measurement. 3. 2 Reagents and materials Unless otherwise specified , all the reagent used should be analytical grade ,

16、 ;water; is distilled wa-ter. 3.2.1 n-hexane: HPLC grade. 3.2.2 acetone: HPLC grade. 5 ? .bzfxw ?SN/T 1774-2006 3.2.3 Sodium chloride solution 150 g/ L. 3: 2. 4 Sulfuric acid. 3.2.5 Anhydrous sodium sulfate: ignite for 4 h at 650 C, and keep in a tightly closed container. 3.2.6 Satandard of ocichlor

17、odipropyl ether: purity>99%. 3.2.7 Stock 臼蚓t阳and叫回础lutd由a叫毗(3.2.6) ， dis盹solve v叫叫、让训it甘怕ha丁n忏时1下斗hexanea町an町剧n时11叩0o I;g/ mL. The SOll阳uti旧。on s由ha甜11 be stored itl 4 C r陌ef制r忖iger阳at。r即y. According to the requirement , is pre. pared from the stock standard solution by n-hexane and dilutedto the

18、 required concentration. / 3.3 Apparatus and equipment / 斗0;3.3. 1 Gas chromatography, equipped -Vith electron capture detector. / 3. 3. 2 Rotary vacuum evaporator. 3.3.3 High speed bler回坚;，;.;- -;十-;-.;-一哺3.3. 4 Column of anhydrous sodium sulfate: 80 mm x 40 mm (id) cylinder funnel , pack with ca 5

19、 mm absorbent cotton at the bottom of the column and fill in 50 mm anhydrous sodium sulfate (口.弘)3. 4 Procedure /tJf1 3.4.1EXtraction j/i Weigh ca 3 9 of the tstsam?le (accurate to O. Og) into a 100mL be宇ker. Add 10 mL water and stand to 2 hours. Add.20 mL cetone ， mixed 2 mln in high speed blendr ，

20、 filter the extracted solu-tion with a filter paper into a 2号。 mL semmtoryTunnel wh怕 ls addedpomL sodium chloride solu-tio川.2.3) and 20 mL 1-hexane, use 1怕Om吼L ac臼e阳 to nn阳1let stand to separating , collet n-hexane layer. Add 25 mL n-hexane to, water layer , repeat the opera-j tion again. Combine th

21、e ril)exane layers throgh column of anhyd叩us sodium sulfate(3. 3. 4) into a 、 F100mL round bottom flask and 崎雪， n-hel伊e to rinse thecol-TFCormnethesolution and evapo阳teto nearly dryness at rotary vacuum evaporator bleow 45 C.-3. 4. 2 Clean up Add 2 mL n-hexane and 2 mL n-hexane to dissolve the resid

22、ue of the round bottom flask , transfer the above solution into 10 mL centrifuge tube with stopper , blow just dryness with N, gas. Add ex-6 SN/T 1774-2006 actly 3. 0 mL n-hexane and O. 5 mL sulfuric acid into the 10 mL centrifuge tube. The 10 mL centrifuge tube is shaked , and centrifuged for 2 min

23、 under 4 000 r/min. The down layer is discarded with pipet , repeat the procedure again until the n-hexane layer is colourless. The n-hexane is ready for GC deter-mination. 3. 4. 3 Determination 3. 4. 3. 1 GC operating :condition a) Chromatographic column: Fused sili回国pillary column , DB-1 30 /TI X

24、O. 25 mm (id) X O. 25m (film thickness) or equivalent , b) Carrier gas and H=KE二叩 gas: N时og函 (purity > 99. 999%); Flow rate of 臼rrier gas: 1.0 mL/min , flow rate of make-up gas: 30 mL/min, h c) Temperature programme: 70t ( 1 min) ,10t/min tO ,2BOt (5 min) , d) Injection port temperature: 200t , e

25、) Detector temperature: 300t , f) Injection mode: Splitless, g) Purge valve: 1 min on, h) Injection volume: 1L. 3. 4. 3. 2 GC determination ;一一一一一一一一一 A 叩According to the concentrations of octachlorodipropyl ether , select the standard working solution with similar peak area to that of sample soluti

26、on. The responses of octachlorodipropyl ether in the standard working solution and the sample solution should be within the linear range of the instrumen-tal detection. The standard working solution should be randomly injected in between the injections of sample solution of equal volume. Undr the ab

27、ove GC operating condiiion , For chromatogram of the standard see F刷re A1in annex AJ / 3. 4. 3. 3 Blank test 扩白 飞飞导月zi 吁The operation of the blank testis thesame as the described in the methof determination , but with the omission of sample addition. If the solvent purity , instrument and jest envir

28、onment conditions , meet demands ,blank test should not have disturbing peaks. f 3. 4. 3. 4 Calculation andexpression of result 于Calculation the content of octachlorodipropyl ether residJE!Jn- the test sample by GC data processor or according to the formula (1) : A X CX V x= 一一一一一一. (1 ) AsX m where

29、 X一一-the residue content of octachlorodipropyl ether in the test samp怡， mg/kg, 7 ? .bzfxw ?SN/T 1774-2006 A一一一the peak area of octachlorodipropyl ether in sample solution , As一一一the peak area of octachlorodipropyl ether in standard working solution , c一-the concentration of octachlorodipropyl ether in working solution.g/mL ， V一一一the final volume of the sample solution. mL,