双波长K系数—标准加入吸光光度法同时测定锰和锌

研究应用双波长K系数—标准加入吸光光度法同时测定锰和锌二组分混合物.试验确定了锰和锌测定中K_(Mn)与K_(Zn)的回归方程.对合成试样、人发试样测定,结果满意.     

汞的形态分析研究 Ⅱ.固相萃取预富集-液相色谱分离测定不同形态的有机汞

本文报道了固相萃取预富集处理样品继以液相色谱分离测定不同形态痕量有机汞的方法.二乙基二硫代氨基甲酸钠(DDTC)作络合剂及甲醇作洗脱液的预富集系统能在线富集甲基汞(MeHg)、乙基汞(EtHg)和苯基汞(PhHg).用于测定加标海水中MeHg、EtHg和PhHg,回收率分别为96.9％、102.4％和98.0％;相对标准偏差分别为3.5％、5.0％和5.0％;检测下限分别为 1.0μg/L、1.2 μg/L和 1.2 μg/L.     

Efficient and mild benzoin condensation reaction catalyzed by simple 1-N-alkyl-3-methylimidazolium salts

The benzoin reaction, catalyzed by simple 1-N-alkyl-3-methylimidazolium salt-based ionic liquid via carbene intermediate, to give the α-hydroxyl ketone proceeds in CH₂Cl₂ under mild conditions.     

超临界流体萃取-胶束电动毛细管色谱法分离测定大黄中蒽醌类组分的含量

采用ＳＴＥ－ＭＥＣＣ法分离测定大黄中的芦荟大黄素，大黄素和大黄酸。萃取条件为压 力４１．４ＭＰａ，温度５０℃，改性剂量０．４ｍＬ。被测组分在１０ｍｉｎ得到全部分离。本法准确、简 便、快速、结果令人满意。     

Two new sesquiterpene lactones with the sulfonic acid group from Saussurea lappa

Two new sesquiterpene lactones with the unusual sulfonic acid group, 13-sulfo-dihydrosantamarine (1) and 13-sulfo-dihydroreynosin (2), have been isolated from the roots of Saussurea lappa C. Their structures, including the absolute configurations, were elucidated by spectroscopic methods.     

环己烯和2-甲基戊烯-1在几种Y型分子筛上的吸附量热研究

用SETARAM热流式量热计测定了环己烯和2-甲基戊烯-1于室温下在NaY、CaY、R_EY和HY等几种分子筛上的微分吸附热。我们又用Benson基团加合法计算得到了生成仲碳离子和叔碳离子时的吸附热。根据实验测得的于不同吸附量时环己烯和2-甲基戊烯-1的吸附热之差值, 对它们在上述几种Y型分子筛上的吸附机理进行了讨论。     

Crystal Structure,Electrochemical Properties and Third-order Nonlinear Optical Response of 4-Methyloxy benzaldehyde Thiosemicarbazone and Its Copper(Ⅱ)Complex

Thecurrentsurgeofinterestinthefield0fnon-linearoptics(NL0)isderivedbothfromaquestforafundamentalunderstanding0fthenon-linearprocess,anditSimPortanceinthetechn0logyofphotonics.Amongnon-linearphen0mena,thethird-ordernon-linearophcsoccuPyanimPortantp0sihonbecauseitprovidesthemechanicsforophcalswitching,ophcallogic,andreal-hmeholograPhy"'.0rganicmaterialwithextendednconjugahonsandlargeRdelocalizahonsarewellknownastheimPortantmaterialsofachievinglargethird-ordernonlinearihes3.ForexamPle,thiosen…     

Synthesis α‐aminonitrile through anodic cyanation of N‐benzylpiperidine

Six‐membered cyclic α‐aminonitrile has been prepared from anodic cyanation of N‐benzylpiperidine. Good yields of α‐aminonitriles could be obtained through potentiostatic electrolysis under different conditions. The results also explain why high yield α‐aminonitriles could not be obtained under constant current electrolysis.     

A practical synthetic route to 4′-alkylaristeromycin derivatives: 4′-methylaristeromycin

(−)-(1S,4R)-4-Hydroxy-2-cyclopenten-1-yl acetate provided a convenient entry point for a 16-step chiral preparation of 4′-methylaristeromycin. This procedure is adaptable to a number of carbocyclic nucleosides with a diversity of substitution at C-4′ and C-5′ and a variety of heterocyclic bases.