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1、7.3.18Table999.04BResultsofinterlaboratorystudyforHCBAOACOfficialMethod999.04TCWGWPSCDeterminationofChlorothalonilNo.oflabs8898andHexachlorobenzeneinTechnicalandFormulatedMaterialsMean(wt%)0.02010.03760.02100.0185CapillaryGasChromatographysr0.00070.00190.00100.0006First
2、Action1999sR0.00120.00210.00450.0010[Thismethodisapplicabletoanalysisoftechnicalmaterial(TC),dryRSDr,%3.55.04.83.4formulations(WPandWG),andaqueous-based(SC)formulationsRSDR,%6.05.521.65.4from50to99%chlorothalonil(CTL)and0.01to0.1%hexachloro-ForTC,WG,andSC,onelaboratoryw
3、asidentifiedasanoutlierbythesinglebenzene(HCB).]Grubb’stest.ForWP,nooutliertestsweresignificant.SeeTables999.04AandBfortheresultsoftheinterlaboratorystudysupportingacceptanceofthemethod.(b)Methanol.—Reagentgradeorbetter.A.Principle(c)n-Butylphthalate.—Reagentgradeorbett
4、er.(d)Phosphoricacid.—85%reagentgradeorbetter.Chlorothalonil(tetrachloroisophthalonitrile,CTL)inTC,WG(e)Internalstandard(IS).—PrepareISsolutionbyweighingandWPproductsisdissolvedwithtoluenecontainingn-butylphthalateasaninternalstandard(IS).Aminormodificationofsol-2.0g(±0
5、.01)n-butylphthalateandquantitativelytransferringtovent(1+1byvolume,methanol+toluenewithIS)ismadeforSC1000mLvolumetricflask.DissolveintolueneforanalysisofTC,formulations.TheCTLandonechemicalimpurity,hexachloroben-WG,andWPformulationsandintoluene–methanol(1+1)forSCzene(H
6、CB),areanalyzedbycapillaryFIDgaschromatographyformulations.TheISfortheSCproductsisamendedwith4–6dropswithaninternalstandard.phosphoricacidaddedforeachliter.(f)Calibrationstandards.—Prepare2HCBstocksolutions.B.ApparatusWeighandrecordtothenearest0.1mg,30mg(±3mg)directlyin
7、to(a)Gaschromatograph.—Withaflameionizationdetectorand100mLvolumetricflasks.Dilutethesestockpreparationstovolumesplit/splitlessinjector.Temperatures:column,205°C;injectionport,withIS.MixwelluntilallHCBdissolves.Dilutestocksolutions330°C;detector,300°C.Gasflows,Hcarriera
8、t25psi(175kPa)col-withIS2/100ineachoftwo100mLvolumetricflasksbypipettingumnheadpressure;splitflow,approximatel
