【英文标准名称】:StandardTestMethodforDeterminingDegreeofDeacetylationinChitosanSaltsbyProtonNuclearMagneticResonance(1HNMR)Spectroscopy
【原文标准名称】:用质子核磁共振(1HNMR)光谱法测定脱乙酰壳多糖盐的脱乙酰作用程度的标准试验方法
【标准号】:ASTMF2260-2003(2008)
【标准状态】:现行
【国别】:美国
【发布日期】:2003
【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】:Chitosansalts;Deacetylation;GlcNAc;Nuclearmagneticresonance(NMR)spectrometry;TEMPs(tissueengineeredmedicalproducts)
【摘要】:Thedegreeofdeacetylationofchitosansaltsisanimportantcharacterizationparametersincethechargedensityofthechitosanmoleculeisresponsibleforpotentialbiologicalandfunctionaleffects.Thedegreeofdeacetylation(%DA)ofwater-solublechitosansaltscanbedeterminedby1Hnuclearmagneticresonancespectroscopy(1HNMR).SeveralworkershavereportedontheNMRdeterminationofchemicalcompositionandsequentialarrangementofmonomerunitsinchitinandchitosan.ThetestmethoddescribedisprimarilybasedontheworkofV?/span>rumetal.(1991),whichrepresentsthefirstpublicationonroutinedeterminationofchemicalcompositioninchitosansbysolutionstate1HNMRspectroscopy.Thistestmethodisapplicablefordeterminingthe%DAofchitosanchlorideandchitosanglutamatesalts.Itisasimple,rapid,andsuitablemethodforroutineuse.Quantitative1HNMRspectroscopyreportsdirectlyontherelativeconcentrationofchemicallydistinctprotonsinthesample,consequently,noassumptions,calibrationcurvesorcalculationsotherthandeterminationofrelativesignalintensityratiosarenecessary.Inordertoobtainwell-resolvedNMRspectra,depolymerizationofchitosanstoanumberaveragedegreeofpolymerization(DPn)of~15to30isrequired.Thisreducestheviscosityandincreasesthemobilityofthemolecules.Althoughthereareseveraloptionsfordepolymerizationofchitosans,themostconvenientprocedureisthatofnitrousaciddegradationindeuteratedwater.Thereactionisselective,stoichiometricwithrespecttoGlcN,rapid,andeasilycontrolled(Allanx0026;Peyron,1995).ThereactionselectivelycleavesafteraGlcN-residue,transformingitinto2,5-anhydro-D-mannose(chitose),consequently,depletionofGlcNafterdepolymerizationisexpected.Ontheotherhand,thechitoseunitdisplayscharacteristic1HNMRsignalstheintensityofwhichmaybeestimatedandutilizedinthecalculationof%DA,eliminatingtheneedforcorrectionfactors.Usingtheintensityofthechitosesignals,thenumberaveragedegreeofpolymerizationcaneasilybecalculatedasacontrolofthedepolymerization.Samplesareequilibratedandanalyzedatatemperatureof90x00B1;1x00B0;C.Elevatedsampletemperaturecontributestoreducingsampleviscosityandrepositionstheprotonsignalofresidualwatertoanareaoutsidethatofinterest.Whilesamplesarenotstoredat90x00B0;Cbutonlyanalyzedatthiselevatedtemperature,theNMRtubesshouldbesealedwithastoppertoavoidanyevaporation.AtasamplepH*of3.8-4.3(see6.1.5below),artifactualdeacetylationofthesampledoesnotoccurduringtheshortequilibrationandanalysistime.AgeneraldescriptionofNMRcanbefoundinx003C;761>oftheUSP24-NF19.1.1ThistestmethodcoversthedeterminationofthedegreeofdeacetylationinchitosanandchitosansaltsintendedforuseinbiomedicalandpharmaceuticalapplicationsaswellasinTissueEngineeredMedicalProducts(TEMPs)byhigh-resolutionprotonNMR(1HNMR).AguideforthecharacterizationofchitosansaltshasbeenpublishedasGuideF2103.1.2Thetestmethodisapplicablefordeterminingthedegreeofdeacetylation(%DA)ofchitosanchlorideandchitosanglutamatesaltsandisvalidfor%DAvaluesfrom50uptoandincluding99.Itissimple,rapid,andsuitableforroutineuse.KnowledgeofthedegreeofdeacetylationisimportantforanunderstandingofthefunctionalityofchitosansaltsinTEMPformulationsandapplications.Thistestmethodwillassistendusersinchoosing......
【中国标准分类号】:C10
【国际标准分类号】:71_040_50
【页数】:5P.;A4
【正文语种】:英语
基本信息
标准名称: | 橡胶中铅含量的测定 原子吸收光谱法 |
英文名称: | Rubber--Determination of lead content by atomic absorption spectrometry |
中标分类: |
化工 >>
橡胶制品及其辅助材料 >>
橡胶制品综合 |
ICS分类: |
橡胶和塑料工业 >>
橡胶
|
替代情况: | GB/T 9874-1988 |
发布部门: | 中华人民共和国国家质量监督检验检疫总局 |
发布日期: | 2001-08-02 |
实施日期: | 2002-05-01 |
首发日期: | 1988-09-20 |
作废日期: | 1900-01-01 |
主管部门: | 中国石油和化学工业协会 |
归口单位: | 全国橡胶与橡胶制品标准化技术委员会 |
起草单位: | 上海橡胶制品研究所 |
出版社: | 中国标准出版社 |
出版日期: | 2004-04-09 |
页数: | 平装16开, 页数:9, 字数:11千字 |
书号: | 155066.1-18058 |
适用范围
本标准规定了采用原子吸收光谱法测定橡胶中铅含量的方法。本标准适用于生胶、混炼胶和橡胶制品。对于铅的浓度无测定限度。只要适当调整试样的量或所用溶液的浓度就可以测定较高或较低的浓度。用标准加入法可以降低测定的下限。
前言
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引用标准
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所属分类: 化工 橡胶制品及其辅助材料 橡胶制品综合 橡胶和塑料工业 橡胶