【英文标准名称】:StandardTestMethodforDeterminingtheMolarMassofSodiumAlginatebySizeExclusionChromatographywithMulti-angleLightScatteringDetection(SEC-MALS)
【原文标准名称】:用体积排阻色谱与多角度光散射检测法(SEC-MALS)测定海藻酸钠的摩尔质量的标准试验方法体
【标准号】:ASTMF2605-2008e1
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:F04.42
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:Alginates;Sizeexclusionchromatographywithmulti-anglelightscatteringdetection(SEC-MALS);Tissueengineeredmedicalproducts(TEMPs)
【摘要】:Thecompositionandsequentialstructureofalginate,aswellasthemolarmassandmolarmassdistribution,determinesthefunctionalityofalginateinanapplication.Forinstance,thegellingpropertiesofanalginatearehighlydependentuponthecompositionandmolarmassofthepolymer.Lightscatteringisoneofveryfewmethodsavailableforthedeterminationofabsolutemolarmassandstructure,anditisapplicableoverthebroadestrangeofmolarmassesofanymethod.Combininglightscatteringdetectionwithsizeexclusionchromatography(SEC),whichsortsmoleculesaccordingtosize,givestheabilitytoanalyzepolydispersesamples,aswellasobtaininginformationonbranchingandmolecularconformation.Thismeansthatboththenumber-averageandmass-averagevaluesformolarmassandsizemaybeobtainedformostsamples.Furthermore,onehastheabilitytocalculatethedistributionsofthemolarmassesandsizes.Multi-anglelaserlightscattering(MALS)isatechniquewheremeasurementsaremadesimultaneouslyoverarangeofdifferentangles.MALSdetectioncanbeusedtoobtaininformationonmolecularsize,sincethisparameterisdeterminedbytheangularvariationofthescatteredlight.Molarmassmayinprinciplebedeterminedbydetectingscatteredlightatasinglelowangle(LALLS).However,advantageswithMALSascomparedtoLALLSare:(1)lessnoiseatlargerangles,(2)theprecisionofmeasurementsaregreatlyimprovedbydetectingatseveralangles,and(3)theabilitytodetectangularvariationallowsdeterminationofsize,branching,aggregation,andmolecularconformation.Sizeexclusionchromatographyusescolumns,whicharetypicallypackedwithpolymerparticlescontaininganetworkofuniformporesintowhichsoluteandsolventmoleculescandiffuse.Whileinthepores,moleculesareeffectivelytrappedandremovedfromtheflowofthemobilephase.Theaverageresidencetimeintheporesdependsuponthesizeofthesolutemolecules.Moleculesthatarelargerthantheaverageporesizeofthepackingareexcludedandexperiencevirtuallynoretention;theseareelutedfirst,inthevoidvolumeofthecolumn.Molecules,whichmaypenetratetheporeswillhavealargervolumeavailablefordiffusion,theywillsufferretentiondependingontheirmolecularsize,withthesmallermoleculeselutinglast.Forpolyelectrolytes,dialysisagainsttheelutionbufferhasbeensuggested,inordertoeliminateDonnan-typeartifactsinthemolarmassdeterminationbylightscattering(1,2).However,inthepresentmethod,thesizeexclusionchromatographystepprecedingthelightscatterdetectionisanefficientsubstituteforadialysisstep.ThesampleisseparatedonSECcolumnswithlargeexcessofelutionbufferfor30to40min,anditisthereforeinfullequilibriumwiththeelutionbufferwhenitreachestheMALSdetector.1.1Thistestmethodcoversthedeterminationofthemolarmassofsodiumalginateintendedforuseinbiomedicalandpharmaceuticalapplicationsaswellasintissueengineeredmedicalproducts(TEMPs)bysizeexclusionchromatographywithmulti-anglelaserlightscatteringdetection(SEC-MALS).AguideforthecharacterizationofalginatehasbeenpublishedasGuideF2064.1.2AlginateusedinTEMPsshouldbewellcharacterized,includingthemolarmassandpolydispersity(molarmassdistribution)inordertoensureuniformityandcorrectfunctionalityinthefinalproduct.Thistestmethodwillassistendusersinchoosingthecorrectalginatefortheirparticularapplication.AlginatemayhaveutilityasascaffoldormatrixmaterialforTEMPs,incellandtissueencapsulationapplications,andindrugdeliveryformulations.1.3Thevalue......
【中国标准分类号】:C10
【国际标准分类号】:11_120_10
【页数】:6P.;A4
【正文语种】:英语