Designation:D1358–86(Reapproved1995)e1StandardTestMethodforSpectrophotometricDieneValueofDehydratedCastorOilandItsDerivatives1ThisstandardisissuedunderthefixeddesignationD1358;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.e1NOTE—UnitofmeasurementstatementandKeywordswereaddededitoriallyinMay1995.1.Scope1.1Thistestmethodcoversthedeterminationofthespec-trophotometricdienevalueasameasureofthecontentofconjugateddienoicacidsindehydratedcastoroilanditsderivatives.Duetothehighlinoleicacidcontentindehydratedcastoroilanditsderivatives,theabsoluteconjugateddienoicacidcontentcannotbedeterminedbythistestmethod.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.SpecifichazardstatementsaregiveninSection6.2.Terminology2.1DescriptionofTermSpecifictoThisStandard:2.1.1spectrophotometricdienevalue—undertheconditionsofthistestmethod,thepercentofconjugateddienoicacids.3.SignificanceandUse3.1Intheprocessofdehydratingcastoroil,adoublebondisformedinthericinoleicacidtomakeeitherconjugatedlinoleicornormallinoleicfattyacidsegmentsintheoil.Thistestmethodattemptstomeasuretheamountofconjugatedunsaturationbymeansoftheabsorbanceataspecificwave-lengthwhichisintheultravioletrange.Sincesomeabsorptionisduetolinoleicacid,acorrectionfactorisincludedinthecalculation.Thistestmethodisonlyapplicabletodehydratedcastoroilproducts.4.Apparatus4.1Spectrophotometer—Ultravioletphotoelectricspectro-photometer,2coveringaspectralrangefrom200to350nm,withawavelengthscalereadableto0.1nm,andequippedwithanabsorptioncell...
