中華人民共和國(guó)出入境檢驗(yàn)檢疫行業(yè)標(biāo)準(zhǔn)SN/T0965—2000進(jìn)出口糧谷中噻吩甲氯殘留量檢驗(yàn)方法2000-09-15發(fā)布中華人民共和國(guó)國(guó)家出入境檢驗(yàn)檢疫局發(fā)布1本標(biāo)準(zhǔn)是按照GB/T1.1—1993《標(biāo)準(zhǔn)化工作導(dǎo)則第1單元：標(biāo)準(zhǔn)的起草與表述規(guī)則第1部分：標(biāo)準(zhǔn)編寫的基本規(guī)定》及SN/T0001—1995《出口商品中農(nóng)藥、獸藥殘留量及生物毒素檢驗(yàn)方法標(biāo)準(zhǔn)編寫的基本規(guī)定》的要求編寫的。其中測(cè)定方法是參考國(guó)內(nèi)外有關(guān)文獻(xiàn)，經(jīng)研究、改進(jìn)和驗(yàn)證后而制定的。本標(biāo)準(zhǔn)同時(shí)制定了抽樣和制樣方法。測(cè)定低限是根據(jù)國(guó)際上對(duì)糧谷中噻吩甲氯殘留量的最高限量和測(cè)定方法的靈敏度而制定的。本標(biāo)準(zhǔn)附錄A是提示的附錄。本標(biāo)準(zhǔn)由中華人民共和國(guó)國(guó)家出人境檢驗(yàn)檢疫局提出并歸口。本標(biāo)準(zhǔn)由中華人民共和國(guó)吉林出人境檢驗(yàn)檢疫局、中國(guó)科學(xué)院長(zhǎng)春應(yīng)用化學(xué)研究所負(fù)責(zé)起草。本標(biāo)準(zhǔn)系首次發(fā)布的行業(yè)標(biāo)準(zhǔn)。1進(jìn)出口糧谷中噻吩甲氯殘留量檢驗(yàn)方法Methodforthedeterminationofthenylchlor1范圍本標(biāo)準(zhǔn)規(guī)定了進(jìn)出口糧谷中噻吩甲氯殘留量檢驗(yàn)的抽樣、制樣和氣相色譜氮磷檢測(cè)器法或氣相色譜質(zhì)量選擇檢測(cè)器法測(cè)定及氣相色譜-質(zhì)譜確證方法。本標(biāo)準(zhǔn)適用于進(jìn)出口糙米、玉米中噻吩甲氯殘留量的檢驗(yàn)。2抽樣和制樣以不超過200t為一檢驗(yàn)批。200t袋裝糙米約4000袋；袋裝玉米約2200袋。玉米有時(shí)為散裝品。2.2抽樣數(shù)量2.2.1袋裝貨品按式(1)計(jì)算抽樣袋數(shù)：a=√N(yùn)……………(1)a——抽樣袋數(shù)。2.2.2散積貨品(玉米)貨堆高度不超過2m。按貨堆面積劃區(qū)設(shè)點(diǎn)。以50m2為一個(gè)取樣區(qū)，每區(qū)設(shè)中心及四角(距邊線1m處)5個(gè)點(diǎn)。每增加一個(gè)取樣區(qū)，增設(shè)3個(gè)點(diǎn)。2.3抽樣工具2.3.1金屬單管取樣器：全長(zhǎng)55cm(包括手柄),直徑1.5cm～2.0cm,溝槽長(zhǎng)度應(yīng)超過袋對(duì)角線長(zhǎng)度2.3.2金屬雙套管取樣器：全長(zhǎng)分1m、2m(均包括手柄)兩種。內(nèi)、外管同部位分段開幾個(gè)槽口，每個(gè)槽口長(zhǎng)15cm～20cm,口寬2.0cm～2.5cm。內(nèi)管的內(nèi)徑為2.5cm～3.0cm;取樣器的探頭長(zhǎng)約7cm。2.3.3取樣鏟或取樣勺。2.3.4分樣板。2.3.6分樣布或適用鋪墊物。2.4抽樣方法倒包抽樣：從堆垛的各部位隨機(jī)抽取2.2.1規(guī)定的應(yīng)抽樣袋數(shù)的10%(每批一般不少于3中華人民共和國(guó)國(guó)家出入境檢驗(yàn)檢疫局2000-09-15批準(zhǔn)2000-12-31實(shí)施SN/T0965—20002袋),將袋口縫線全部拆開，平置于分樣布或其他潔凈的鋪墊物上，雙手緊握袋底兩角，提起約成45°傾角，倒拖約1m,使袋內(nèi)貨物全部倒出。查看袋內(nèi)和袋間品質(zhì)是否均勻。確認(rèn)情況正常后，用取樣鏟隨機(jī)在各部位抽取樣品，并立即將樣品倒入盛樣器內(nèi)。每袋抽取樣品的數(shù)量應(yīng)基本一致。袋內(nèi)抽樣：按2.2.1規(guī)定的應(yīng)抽樣袋數(shù)(扣除倒包抽樣袋數(shù)),在堆垛四周的上、中、下各層以曲線形走向隨機(jī)抽取。然后按糙米、玉米，用下述方法進(jìn)行取樣：對(duì)糙米，用金屬單管取樣器槽口朝下，從每袋一角依斜對(duì)角方向插入袋內(nèi)，然后將管槽旋轉(zhuǎn)朝上，抽出取樣器，立即將樣品倒入盛樣器內(nèi)。對(duì)玉米，用1m長(zhǎng)的金屬雙套管取樣器，關(guān)閉槽口，從每袋一角依斜對(duì)角方向插入袋內(nèi)，然后旋轉(zhuǎn)內(nèi)管以開啟槽口，待樣品流滿內(nèi)管后，再旋轉(zhuǎn)內(nèi)管以關(guān)閉槽口。抽出取樣器，立即將樣品倒入盛樣器內(nèi)。每袋抽取樣品的數(shù)量應(yīng)與基本一致。每批所抽取的樣品總量應(yīng)不少于4kg。2.4.2散積抽樣按2.2.2規(guī)定的取樣點(diǎn)，逐點(diǎn)抽取樣品。將金屬雙套管取樣器槽口關(guān)閉，以傾斜45°插入貨堆至相應(yīng)深度，旋轉(zhuǎn)取樣器內(nèi)管以開啟槽口，待樣品流滿內(nèi)管后，再旋轉(zhuǎn)內(nèi)管以關(guān)閉槽口。抽出取樣器，立即將樣品倒入盛樣器內(nèi)，從各點(diǎn)所抽取樣品的數(shù)量應(yīng)基本保持一致。每批所抽取的樣品總量應(yīng)不少于4kg。2.4.3大樣縮分袋裝樣品：合并從倒包和袋內(nèi)抽樣所取全部樣品，倒于分樣布上，用分樣板按四分法縮分樣品至不少于2kg,倒入盛樣器內(nèi)，加封后標(biāo)明標(biāo)記，并及時(shí)送交實(shí)驗(yàn)室。2.5.1制樣工具磨碎機(jī)。2.5.2制樣方法將樣品按四分法縮分至1kg,用磨碎機(jī)全部磨碎并通過20目篩?；靹颍殖蓛煞葑鳛樵嚇?，分裝2.6試樣保存將試樣于一5℃以下避光保存。注：在抽樣及制樣的操作過程中，必須防止樣品受到污染或發(fā)生殘留物含量的變化。3測(cè)定方法3.1方法提要試樣中殘留的噻吩甲氯用水-丙酮提取，提取液經(jīng)與石油醚液-液分配后，再以弗羅里硅土柱凈化，被測(cè)物用丙酮-石油醚洗脫，洗脫液經(jīng)蒸干，殘?jiān)帽芙獠⒍ㄈ?，溶液供配有氮磷檢測(cè)器或質(zhì)量選擇檢測(cè)器的氣相色譜儀測(cè)定，外標(biāo)法定量。必要時(shí)用氣相色譜-質(zhì)譜進(jìn)行確證。3.2試劑和材料3.2.3無水硫酸鈉：650℃灼燒4h,貯于密封容器中備用。33.2.5弗羅里硅土：層析用，100～200目，650℃灼燒5h,用前于130℃活化4h,冷卻后加入2%3.2.6噻吩甲氯標(biāo)準(zhǔn)品：純度≥99%。3.2.7噻吩甲氯標(biāo)準(zhǔn)溶液：準(zhǔn)確稱取適量的噻吩甲氯標(biāo)準(zhǔn)品，用少量的丙酮溶解，并以丙酮配制成濃度為1.00mg/mL的標(biāo)準(zhǔn)儲(chǔ)備液。根據(jù)需要再用丙酮稀釋成適用濃度的標(biāo)準(zhǔn)工作溶液。3.3儀器和設(shè)備3.3.1氣相色譜儀：配有氮磷檢測(cè)器(NPD)及質(zhì)量選擇檢測(cè)器(MSD)。3.3.2振蕩器。3.3.3旋轉(zhuǎn)蒸發(fā)器。3.3.4無水硫酸鈉柱：7.5cm×1.5cm(內(nèi)徑),內(nèi)裝5cm高無水硫酸鈉。3.3.5弗羅里硅土柱：25cm×1.5cm(內(nèi)徑),自下而上依次填裝2cm高無水硫酸鈉、10g弗羅里硅土、2cm高無水硫酸鈉。使用前用50mL石油醚預(yù)淋洗。3.4測(cè)定步驟稱取試樣約20g(精確至0.1g)于250mL具塞錐形瓶中，加入40mL水，放置2h。然后加入150mL丙酮，振蕩提取30min。將提取液過濾于500mL分液漏斗中，殘?jiān)儆?0mL丙酮重復(fù)提取一次，合并濾液于上述分液漏斗中。然后加入200mL硫酸鈉水溶液和50mL石油醚，振搖3min,靜置分層。收集上層有機(jī)相。水相再用2×50mL石油醚重復(fù)提取兩次，合并有機(jī)相。經(jīng)無水硫酸鈉柱脫水，收集于250mL梨形瓶中，于40℃水浴中旋轉(zhuǎn)濃縮至近干，加入10mL丙酮-石油醚(5+95)以溶解殘?jiān)?。將溶解液傾入弗羅里硅土柱中，用50mL丙酮-石油醚(5+95)進(jìn)行淋洗，棄去流出液，然后用50mL丙酮-石油醚(1+9)進(jìn)行洗脫。收集全部洗脫液于250mL梨形瓶中。于40℃水浴中旋轉(zhuǎn)濃縮至干，用丙酮溶解并定容至5.0mL,供氣相色譜測(cè)定。3.4.3測(cè)定氣相色譜氮磷檢測(cè)器(NPD)測(cè)定條件a)色譜柱：25m×0.32mm(內(nèi)徑),膜厚0.25μm,HP-1701石英毛細(xì)管柱，或相當(dāng)者；c)進(jìn)樣口溫度：270℃;d)檢測(cè)器溫度：280℃;氣相色譜儀質(zhì)量選擇檢測(cè)器(MSD)測(cè)定條件d)色譜-質(zhì)譜接口溫度：260℃;e)載氣：氦氣，純度≥99.99%,1.2mL/min;SN/T0965—20004g)進(jìn)樣方式：無分流進(jìn)樣，1.5min后開閥；h)電離方式：EI;i)電離能量：70eV;j)電子倍增器電壓：1.5kV;k)測(cè)定方式：選擇離子監(jiān)測(cè)方式；1)選擇監(jiān)測(cè)離子(m/z):287、288、323amu;m)溶劑延遲：5min。色譜測(cè)定根據(jù)樣液中被測(cè)農(nóng)藥含量情況，選定濃度相近的標(biāo)準(zhǔn)工作溶液。標(biāo)準(zhǔn)工作溶液和待測(cè)樣液中農(nóng)藥的響應(yīng)值均應(yīng)在儀器檢測(cè)的線性范圍內(nèi)。對(duì)標(biāo)準(zhǔn)工作溶液與樣液等體積參插進(jìn)樣測(cè)定。在色譜條件下，噻吩甲氯的保留時(shí)間約為15min,在色譜條件下，噻吩甲氯的保留時(shí)間約為18min。標(biāo)準(zhǔn)品的氣相色譜圖見附錄A中圖A1、圖A2。氣相色譜-質(zhì)譜條件與條件相同。質(zhì)譜確證試驗(yàn)對(duì)標(biāo)準(zhǔn)溶液及樣液均按規(guī)定的條件進(jìn)行測(cè)定時(shí)，如果樣液與標(biāo)準(zhǔn)溶液的選擇離子圖中，在相同保留時(shí)間有峰出現(xiàn)，則根據(jù)選擇離子m/z287、288、323(其豐度比46:100:11)對(duì)其確證。標(biāo)準(zhǔn)品的氣相色譜-質(zhì)譜圖見附錄A中圖A3。3.4.5空白試驗(yàn)除不加試樣外，均按上述測(cè)定步驟進(jìn)行。3.5結(jié)果計(jì)算和表述用色譜數(shù)據(jù)處理機(jī)或按式(2)計(jì)算試樣中噻吩甲氯殘留含量： (2)式中：X——試樣中噻吩甲氯殘留含量，mg/kg;h——樣液中噻吩甲氯的色譜峰高，mm;,h.——標(biāo)準(zhǔn)工作液中噻吩甲氯的色譜峰高，mm;c——標(biāo)準(zhǔn)工作液中噻吩甲氯的濃度，pg/mL;V樣液最終定容體積，mL;m——最終樣液所代表的試樣量，g。4測(cè)定低限、回收率4.1測(cè)定低限本方法的測(cè)定低限為0.02mg/kg。4.2回收率4.2.1氣相色譜氮磷檢測(cè)器(NPD)測(cè)定糙米中噻吩甲氯的添加濃度及其回收率實(shí)驗(yàn)數(shù)據(jù)：在0.02在0.10在1.00mg/kgmg/kgmg/kg時(shí)，回收率為95.2%;時(shí)，回收率為88.5%;時(shí)，回收率為90.0%。玉米中噻吩甲氯的添加濃度及其回收率實(shí)驗(yàn)數(shù)據(jù)：5在0.02mg/kg時(shí)，回收率為89.5%;在0.10mg/kg時(shí)，回收率為94.0%;在1.00mg/kg時(shí)，回收率為88.9%。4.2.2氣相色譜質(zhì)量選擇檢測(cè)器(MSD)測(cè)定糙米中噻吩甲氯的添加濃度及其回收率實(shí)驗(yàn)數(shù)據(jù)：在0.02mg/kg時(shí)，回收率為97.2%;在0.10mg/kg時(shí)，回收率為88.0%;在1.00mg/kg時(shí)，回收率為88.8%。玉米中噻吩甲氯的添加濃度及其回收率實(shí)驗(yàn)數(shù)據(jù)：在0.02mg/kg時(shí)，回收率為92.2%;在0.10mg/kg時(shí)，回收率為88.0%;在1.00mg/kg時(shí)，回收率為87.0%。SN/T0965—20006(提示的附錄)標(biāo)準(zhǔn)品的氣相色譜圖圖A1噻吩甲氯標(biāo)準(zhǔn)品氣相色譜圖(NPD)7圖A2噻吩甲氯標(biāo)準(zhǔn)品氣相色譜圖(MSD)a)選擇離子色譜圖b)標(biāo)準(zhǔn)品質(zhì)譜圖c)選擇離子質(zhì)譜圖圖A3噻吩甲氯標(biāo)準(zhǔn)品氣相色譜-質(zhì)譜圖8ThisstandardwasdraftedinaccordancewiththerequirementsofGB/T1.1—1993“Directivesforworkofstandardizationunit1:Draftingandpresentingofstandard-Part1:generalrulesfordraftingstandards”andSN/T0001—1995“Generalrulesfordraftingthestandardmethodstionofpesticide,veterinarydrugresiduesandbiotoxinsincommoditiesforexport".Themethodofde-terminationofthisstandardwasdraftedbyreferringtorelevantdomesticandforeignliteraturesthroughresearch,modificationandverification.Inaddition,methodsofsamplingandsampleprepara-Thelimitofdeterminationisdefinedinthisstandardonthebasisofthecurrentinternationalmaxi-mumlimitsforthenylchlorresiduesincerealsandthesensitivityofthemethod.AnnexAofthisstandardisaninformativeannex.ThisstandardwasproposedbyandisunderthechargeoftheStateAdministrationofEntry-ExitIn-spectionandQuarantineofthePeople'sRepublicofChina.ThisstandardwasdraftedbytheJilinEntry-ExitInspectionandQuarantineBureauofthePeople'sRepublicofChinaandChangchunInstituteofAppliedChemistry,ChinesAcademyofSciences.ThemaindrafterofthisstandardisMuJunandJiaYiqun.ThisstandardisprofessionalstandardpromulgatedforthNote:ThisEnglishversion,atranslationfromtheChinesetext,issolelyforguidance.9Thisstandardspecifiesthemethodofsampling,samplepreparationanddeterminationofthenfirmationbygaschbeca4000bags;formaizeiThecargoofmaizei2.2QuantityofsN—totalnumberofbagsia—numberofbagstobetaken.corners(1mfromthemargins)ofthearea.Foranadditionalarea,threemoresamplingspotsshallbeApprovedbytheStateAdministrationforEn-try-ExitInspectionandQple'sRepubiicofChinSN/T0965—20002.3Samplingtools2.3.1Metallicsampler:Length(includinghandle);55cm;diameter:1.5cm～2.0cm;groovelength:longerthanhalfofthediagonallengthofthebag.2.3.2Metallicdouble-casingsampler:length1m,2m(bothincludinghandle)withsomeslotsondifferentsectionsandrespectivelyatthesameheightsforbothinnerandoutercasings;lengthofslots:15cm～20cm,widthoftheslots:2.0cm～2.5cm;insidediameteroftheinnercasing:2.5cm~3.0cm;theprobelengthofthesampler:ca7c2.3.4Plateforquartering.2.3.5Samplecontainer:Canorbag,whichcanbesealed.2.3.6Cloth(orothersuitablematerial)sheet:Forsampledividing(quartering).2.4SamplingprocedureSamplingbyemptyingout:Draw10percentofthenumberofbagsspecifiedin2.2.1(notlessthan3bags)atanypartofthepileatrandom.Unseamandopenthebag,andlayitonacleanclothsheet(orothercleansheet).Grasptighttwocornersofthebagbottomandraiseuptoanangleof45°,tugbackwardforca1muntilallcontentofthebagisemptiedout.Checkwhetherthequalityofgoodsisuniformwithinandbetweenthebags.Afterconfirmingthegoodsareinnormalcondition,scoopupthesamplefromdifferentpartsoftheout-pouredcontentatrandom,andpromptlyplaceinasamplecontainer.Thequantityofsampledrawnfromeachbagshouldbebasicallythesame.Samplingfrominsidethebags:Drawthesamplesfromthenumberofbagsspecifiedin2.2.1(bydeductingthenumberofbagsdrawnin)asfollows:Alongthesinewaveofthepile,drawthesamplesfromthebagsofupper,middleandlowerpartsaroundthepileatrandom.Forunpolishedriceormaizeproceedasfollows:Forunpolishedrice,usingthemetallicsampler,insertitwithitsgroovefacingdownward,diagonallyintoeachbag,thenturnthesampler180°,drcontainer.Formaize,usingthemetallicdouble-casingsampler(length1m)(theslsertingin)diagonallyinsertintoeamayfilluptheinnertube.AgainturntheiPromptlypourthesampleintoTheamountofsampledrawnfromeachbagshouldbebasicallythesameasin().Thetotalweightofthesampleofeachlotshouldbenotlessthan4kg.ThetotalweightofthesampleofeachloForcargoinbags:Pourallthesamples(frombothand2.4.2.5PreparationoftestsampleSamplecontainer:Wide-mouthbottle,withgrNote:Inthecourseofsamplingandsamplepreparation,precautionsmustbetakentoavoidcontaminationoranyfactorsthatmaycausethechangeofresiduecontent.Thethenylchlorresiduesinthetestsampleareextractedwithwater-acetone.Theextractitionedwithpetroleumether.Cdefinitevolumewithacetone.Determinationismadebymeansonitrogen-phosphorusdetectorormassselectivedetector,usingexternalthethenylchlorisconfirmedbyGC-MS.3.2ReagentsandmaterialsUnlessotherwisespecified,allthereagentsusedshouldbeanalyticallypure,"water"isdistilledwa-ter.for4handdeactivatebyadding2%(m3.2.6Thenylchlorstandard:Purity≥99%.3.2.7Thenylchlorstandardsolution:Accuratelyweighanadequateamountoffacetone.Dilutewithacetonetoformastanfconcentrationasthes3.3Apparatusandequipment3.3.1Gaschromatographequippedwithnitrogen-phosphorusdetector(NPD)andmassselectivede-tector(MSD).3.3.3Rotaryvacuumevaporat3.3.4Columnofanhydroussodiumsulfate:7.5cm×1.5cm(i3.3.5Florisilcolumn:25cm×1.5cm(id),afate,10gofFlorisil,2cm(height)ofanhydroussodiumsulfate.Rinsethecolumnwith50mLofpetroleumetherbeforeuse.Weighca20g(accurateto0.1g)ofthete40mLofwaterandletstandfor2h.Add150mLofacetoneandextractfor30minonashaker.Filtertheextractintoa500mLseparatoryfunnel.Rinsetheresiduetwicewith50mL(intotal)ofacetone,filterandcombinethewashingsintothesameseparatoryfunnel.Add200mLofsodiumsulfatesolu.tionand50mLofpetroleumeganicphase.Thewaterphaseisagainextractedwith2×50mLofpetroleumether.Combinedtheor-ganicphases,andletpassthroughacolumnofanhydroussodiumsulfatetoremovethewater.Collecttheeffluentina250mLpear-shapedbottleandevaporabathtemperaturebelow40℃.Dissolvetheresiduewith10mLofacetone-petroleumether(5+95).TransfertheabovesolutionintoanFlorisilcolumn.Washthecolumnwith50mLofacetone-petroleumether(5+95)anddiscardtheeffluent.Thenelutewith50mLofacetone-petroleumether(1+9),collectalltheeluratorwithabathtemperaturebelow40℃.Dissolvetheresidueanddiluteexactlyto5.00mLwithace-3.4.3Determinnationa)Chromatographiccolumn:25m×0.32mm(id),0.25μmfilmthickness,HP-1701,silicacapillaryc)Injectionporttemperature:270℃;e)Carriergas:Nitrogen,purity≥99.99%,2mL/min;f)Hydrogen:4mL/min;g)Air:100mL/min;h)Make-upgas:Nitrogen,purity≥99.99%,30mL/min;i)Injectionmode:Splitless,puj)Injectionvolume:2μL.a)Chromatographiccolumn:30m×0.25mm(id),0.25μmfilmthickness,DB-17,silicacapillarycol-c)Injectionporttemperate)Carriergas:Helium,purity≥99.99%,1.2mL/min;g)Injectionmode:Splitless,purgeonh)Electronionizationmode:EI;j)Electronicmulitpliervoltage:1.5kV;k)Determinationmode:SIMmode;1)Selectedmonitoringion(m/m)Solventprotectiondelay:5min.Accordingtotheapproximateconcentrationofthepesticideinthesamplesolution,selectthestandardworkingsolutionwithsimilarpeakheighttothatofthesamplesolution.Theresponsesofpesticideinthestandardworkingsolutionandsamplesolutionshouldbewithinthelinearrangeoftheinstrumen-taldetection.Thestandardworkingsolutionshouldberandomlyinjectedin-betweentheinjectionsofthesamplesolutionofequalvolume.Underthechromatographiccondition,theretentiontimeofthenylchlorisca15min,Underthechromatographiceondition,theretentiontimeofthenylchlorisca18min.Forgaschromatogramofthestandard,seefigureA1andfigureA2in3.4.4ConfirmatiorGC-MSoperatingconditionTheoperatingconditionisthesameasthatdescribedin.GC-MSconfirmatorytestAccordindingtotheoperationconditionassignedin,analyzethestandardsolusolution.Ifthereisanypeakofsamplesolutionappearedatthesameretentiontimeassuchpeakofthestandardsolution,itmustbeconfirmedbyselectedmonitoringions(m/z)287,288,323(abundanceratioisca46:100:11)withGC-MS.Forgaschromatogramandmassspectrumofthestandard,see3.4.5BlanktestTheoperationoftheblanktestisthesameasthatdescribedinthemethodofdeterminationbutwithomissionofsampleaddition.3.5CalculationandexpressionoftheresultCalculatethecontentofthenylchlorresiduesinthetestsamplebyGCdataprocessororaccordingtotheformula(2).…………whereX—theresiduecontentofthenylchlorinthetestsample,mg/kg;h—thepeakheightofthenylchlorinthesamplesolution,mm;h?—thepeakheightofthenylchlorinthestandardworkingsolution,mm;c—theconcentrationofthenylchlorinthestandardworkingsolution,pg/mL;V—thefinalvolumeofthesample