简介:建立槟榔中槟榔碱的高效液相色谱-电喷雾质谱(HPLC—ESI-MS)检测方法。通过优化色谱和质谱条件,以β-蒎烯为内标物,利用质谱定性和色谱定量测定槟榔碱的含量。槟榔碱在质量浓度为10.8~86.4μg/mL时的线性关系良好,R=0.9985;最低检测限为0.4μg/mL(S/N=3);最低定量限为0.9μg/mL(S/N=10);平均回收率为98.32%,RSD为3.44%(n=5)。该方法具有流动相简单、分析时间短,以及不需对样品进行衍生,操作简便、定量准确和抗干扰能力强等优点。
简介:淀粉含量是烤烟烟叶醇化品质高低的一项重要指标,但目前淀粉含量测定方法较多且缺乏系统比较,造成不同测定方法获得结果横向比较性较差。本研究系统地比较了连续流动法、碘显色法、费林试剂滴定法、离子色谱法以及高效液相色谱法5种常见的淀粉含量的测定方法在红花大金元和K326烟叶淀粉含量测定中的应用。使用5种方法测定了两个醇化初期烟叶样品中的淀粉含量,采用标准偏差、回收率以及t检验法,比较了烟草行业标准方法连续流动分析法与其他测定方法结果之间的差异性。结果表明,与行业标准连续流动法相比,费林试剂滴定法以及酶水解—离子色谱法,测定结果偏高,且准确度偏低;酸水解-高效液相色谱法测定结果偏低,虽具有很高的精密度,但准确性不高;而碘显色法测定结果不但表现出较高的准确性和精密度,且与连续流动法的测定结果之间不存在显著性差异(t
简介:Undisturbedsoilcorewithmanymacroporesanddisturbedsoilcorewithonlyonemacropore(diameteris10mm)wereprobedbyx-raycomputedtomography(CT).Thesize,number,shapeandcontinuityofmacroporesinthetransverseandverticalsectionsofsoilwerecharacterizedusingCTscanningimages.TheprobabilitydensitiesofmacroporesinthetransversesectionofsoilcoreexhibitedalogarithmicΓdistribution.ResultsindicatedthatCTscanningwasapromisingnondestructivemethodforcharacterizingmacroporesinsoils.
简介:InordertoexplorethefeasibilityofusingX-raytomeasuremoisturecontentinthedryingprocessandhaveafurtherstudyontheeffectofprecisionofmoisturecontentwhenscanningthroughdifferentgraindirections,X-rayscanningmethodandweightingmethodwereusedtomeasureaveragemoisturecontentofCunninghamialanceolataduringhotairdrying.Theresultsshowthatthemoisturecontentvaluesoftwomethodswereveryclosetooneanother,thedeterminationcoefficientsofbothwerehighlycorrelatedwithavalueover0.99,andtheabsolutedeviationwasbelow2%;whenscanningalongradialdirectionandlongitudinaldirection,theprecisionsofaveragemoisturecontentwerehigherthanthatofthetangentialdirection,butthedeviationcanbenegligibleintheactualmeasurement;inthepracticalapplication,theeffectofgraindirectiononprecisionofmoisturecontentmeasurementcouldnotbetakenintoaccountwhenusingX-raytomeasurethemoisturedistributionofwood.