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1、纤维素提取方法简介Howcouldweextractcellulosefromtreering-stepbystepPeiliFU(付培立)March14th2014referencesWielochT,HelleG,HeinrichI,etal.Anoveldeviceforbatch-wiseisolationofα-cellulosefromsmall-amountwholewoodsamples[J].Dendrochronologia,2011,29(2):115-117.LaumerW,AndreuL,HelleG,etal.Ano
2、velapproachforthehomogenizationofcellulosetousemicro‐amountsforstableisotopeanalyses[J].RapidCommunicationsinMassSpectrometry,2009,23(13):1934-1940.主要步骤MainproceduresCrossdatingandSamplecutting;ExtractionHomogenizationFreezedryingWeighingandmeasuredwithmassspectrometry.样品的切取
3、和称量Cuttingandweighing样品大小:厚度thickness0.5-0.8mm;samplesize>500μm样品量sampleamount:>2mgSamplesneededformassspectrometry:onemeasurementof:C130.5mg;O180.3mg;(production~30%)提取extractionNaOH5%solution溶液,60℃,2h,2times次;(近沸腾热的去离子水,洗3次,washed3timeswithboiledde-ionedwater)NaClO27%solut
4、ion溶液,60℃,8h,6times(醋酸溶液aceticacid,调节pH至4-5);(近沸腾热的去离子水,洗3次,washed3timeswithde-ionedboiledwater)NaOH17%solution溶液,室温(roomtemperature),2h,2times次(1%HCl溶液洗1次,近沸腾热的去离子水,洗3次测pH,washedwith1%HCl,thenwashed3timeswithde-ionedboiledwater)判断是否提取完全(completelyextracted?)草酸溶液:每100mlNaClO
5、2加草酸溶液0.5~1ml草酸aceticacidsolutions:0.5ml~1ml/100mlNaClO27%纤维素转移cellulosetransferEppi管清洗(高压气体、去离子水)、加入1ml去离子水;纤维素转移镊子去离子水等冰箱4℃冷藏纤维素的同质化homogenization样品冷藏storeinrefrigerator(+4℃)方法:超声波;ultrasonic设置:cycle0.5,amplitude6-7;继续时间duration30s(13C2*15s18O30s因不同物种而有所差异);判断呈牛奶状(milky),或
6、者纤维素均一(orhomogenized盖上带孔的盖子,至于冰箱中冷冻(为低温真空干燥作准备)storedinrefrigerator-10℃真空低温干燥(freezedry)关闭排气阀、排水阀,检查油泵中油量多少。打开机器和油泵预热30分钟(warmup);将样品放入,一般一次可放入3个eppi板(288个样品左右),主干燥程序,48h;真空度atm降至1.030mbar(maindryingprocess)调节程序至干燥后程序,24h;(afterdryprocess)真空1.030mbar降至0.003~0.005mbar调节至待机程序小
7、心打开排气阀,使压力升至1atm然后取出样品,打开排水阀,关闭机器和泵纤维素称量weighofcellulose使用半微量天平(与称量木材使用同一天平)精度0.01mg同位素测定premeasurement需要量theamountofcelluloseneeded:18O300μg,13C500μg银(18O,Silvercapsule)或者钛(13C,Titaniumcapsule)胶囊裹住;再次干燥:高温、真空将所有的水除去removeallthewaterinsamples;测定:质谱仪spectrometryDrybefroeanaly
8、siswithmassspectrometrySamplesformassspectrometry:O18silvercapsule;C13Titan