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1、如何用核磁确定混合物中各组分的百分含量用1HNMR确定混合物中各组分的相对百分含量是比较方便的.1.要知道原料,产物,溶剂,杂质的结构和分子量.2.正确辨认原料,产物,溶剂,杂质的特征NMR信号,正确积分.3.每个化合物选定一个信号,分别求出一个H的面积.它们之间的比值就是摩尔比.换算成重量比就更容易了.如果原料和产物中都有甲基,那就用二者的CH3信号积分值比,即二者的摩尔比.4.残留溶剂比如醋酸利用CH3的1HNMR信号.5.可以把三个成分作为100%(假定样品中几乎没有水分和无机成分),也可
2、以计算%.方法是比较灵活的.特殊情况的问题再叙.此法比较方便快捷，误差通常在可接受的范围，当然没有色谱法精度高。1HNMR不但可以测定混合物中成分的相对含量,也可以通过加入合适的内标测定绝对含量,有很多文献.有个术语叫QuantitativeNMR(QNMR).国外有1HNMR定量测定天然混合物的论文和综述文章.比如:Basedonabriefrevisionofwhatconstitutesstate-of-the-art"quantitativeexperimentalconditions"
3、for1HquantitativeNMR(qHNMR),thiscomprehensivereviewcontainsalmost200referencesandcoverstheliteraturesince1982withemphasisonnaturalproducts.ItprovidesanoverviewofthebackgroundandapplicationsofqHNMRinnaturalproductsresearch,newmethodssuchasdecouplingan
4、dhyphenation,andanalyticalpotentialandlimitations,andcompilesinformationonreferencematerialsusedforandstudiedbyqHNMR.Thedualstatusofnaturalproducts,beingsinglechemicalentitiesandvaluablebiologicallyactiveagentsthatneedtobepurifiedfromcomplexmatrixes,
5、resultsinanincreasedanalyticaldemandwhentestingtheirdeviationfromthesingletoncompositionideal.TheoutcomeandversatilityofreportedapplicationsleadtotheconclusionthatqHNMRiscurrentlytheprincipalanalyticalmethodtomeetthisdemand.Consideringboth1Dand2D1HNM
6、Rexperiments,qHNMRhasprovedtobehighlysuitableforthesimultaneousselectiverecognitionandquantitativedeterminationofmetabolitesincomplexbiologicalmatrixes.Thisismanifestedbythepriorpublicationofover80reportsonapplicationsinvolvingthequantitationofsingle
7、naturalproductsinplantextracts,dietarymaterials,andmaterialsrepresentingdifferentmetabolicstagesof(micro)organisms.Insummary,qHNMRhasgreatpotentialasananalyticaltoolinboththediscoveryofnewbioactivenaturalproductsandthefieldofmetabolomeanalysis.我和同事发表
8、的1HNMR法定量测定替米考星的含量的论文摘要(分析测试学报)。-----------------------------------------HistoricalBackgroundofqNMR.QuantitativeNMR(qNMR)isalmostasoldasNMRitself.Earlyreportsregardingtheachievableprecisionofquantitationareinconsistent,andsomeofthemeventendedtodenyNM
