Designation:E1747−95(Reapproved2011)StandardGuideforPurityofCarbonDioxideUsedinSupercriticalFluidApplications1ThisstandardisissuedunderthefixeddesignationE1747;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONTherapidcommercialdevelopmentofcarbondioxideforuseinsupercriticalfluidextraction(SFE)andsupercriticalfluidchromatography(SFC)hashastenedtheneedtoestablishcommonpuritystandardstobespecifiedbyspecialtygassuppliers.Asaconsequenceofitsisolationfrompetrochemicalside-streamsorasaby-productoffermentationorammoniasynthesis,carbondioxidecontainsawiderangeofimpuritiesthatcaninterferewithanalyticalquantificationorinstrumentoperation.ThisguideisintendedtoserveasaguidetospecialtygassuppliersfortestingthesuitabilityofcarbondioxideforuseinSFCandSFEapplications.1.Scope1.1ThisguidedefinespuritystandardsforcarbondioxidetoensurethesuitabilityofliquefiedcarbondioxidegasforuseinSFEandSFCapplications(seeGuideE1449fordefinitionsofterms).Thisguidedefinesquantitation,labeling,andstatisticalstandardsforimpuritiesincarbondioxidethatarenecessaryforsuccessfulSFEorSFClaboratorywork,anditsuggestsmethodsofanalysisforquantifyingtheseimpurities.1.2ThisguideisprovidedforusebyspecialtygassupplierswhomanufacturecarbondioxidespecificallyforSFEorSFCapplications.SFEorSFCcarbondioxide(CO2)productsofferedwithaclaimofadherencetothisguidewillmeetcertainabsolutepurityandcontaminantdetectabilityrequire-mentsmatchedtotheneedsofcurrentSFEorSFCtechniques.TheuseofthisguideallowsdifferentSFEorSFCCO2productofferingstobecomparedonanequalpuritybasis.1.3Thisguideconsiderscontaminantstobethosecompo-nentsthateithercausedetectorsignalsthatinterferewiththoseofthetargetanalytesorphysicallyimpedetheSFEorSFCexperiment.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincl...
