美国EPA标准方法

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1、METHOD509DETERMINATIONOFETHYLENETHIOUREA(ETU)INWATERUSINGGASCHROMATOGRAPHYWITHANITROGEN-PHOSPHORUSDETECTORRevision1.0December1992D.J.MunchandR.L.GravesT.M.EngelandS.T.ChampagneBattelle,ColumbusDivisionENVIRONMENTALMONITORINGSYSTEMSLABORATORYOFFICEOFRESEARCHANDDEV

2、ELOPMENTU.S.ENVIRONMENTALPROTECTIONAGENCYCINCINNATI,OHIO45268509-1METHOD509DETERMINATIONOFETHYLENETHIOUREA(ETU)INWATERUSINGGASCHROMATOGRAPHYWITHANITROGEN-PHOSPHORUSDETECTOR1.0SCOPEANDAPPLICATION1.1Thismethodutilizesgaschromatography(GC)todetermineethylenethiourea

3、(ETU,ChemicalAbstractsRegistryNo.96-45-7)inwater.1.2Thismethodhasbeenvalidatedinasinglelaboratoryduringdevelopment.1Themethoddetectionlimit(MDL)hasbeendeterminedinreagentwaterandislistedinTable2.Methoddetectionlimitsmayvaryamonglaboratories,dependingupontheanalyt

4、icalinstrumentationusedandtheexperienceoftheanalyst.InadditiontotheworkdoneduringthedevelopmentofthismethodanditsuseintheNationalPesticideSurvey,aninterlaboratorymethodvalidationstudyofthismethodhasbeenconducted.1.3Thismethodisrestrictedtousebyorunderthesupervisi

5、onofanalystsexperiencedintheuseofGCandintheinterpretationofgaschromatograms.EachanalystmustdemonstratetheabilitytogenerateacceptableresultswiththismethodusingtheproceduredescribedinSection9.3.1.4WhenatentativeidentificationofETUismadeusingtherecommendedprimaryGCc

6、olumn(Section6.7.1),itmustbeconfirmedbyatleastoneadditionalqualitativetechnique.ThistechniquemaybetheuseoftheconfirmationGCcolumn(Section6.7.2)withthenitrogen-phosphorusdetectororanalysisusingagaschromatograph/massspectrometer(GC/MS).2.0SUMMARYOFMETHOD2.1Theionic

7、strengthandpHofameasured50mLaliquotofsampleareadjustedbyadditionofammoniumchlorideandpotassiumfluoride.ThesampleispouredontoanExtrelutcolumn.ETUiselutedfromthecolumnin400mLofmethylenechloride.Afreeradicalscavengeristhenaddedinexcesstotheeluate.Themethylenechlorid

8、eeluantisconcentratedtoavolumeof5mLaftersolventsubstitutionwithethylacetate.GaschromatographicconditionsaredescribedwhichpermittheseparationandmeasurementofETU