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.     

Synthesis of (s)-(-)-Benzyl-2-tert-butoxycarbonyl amino-4-iodobutyrate

The proteinogenic (-amino acids constitute an important section of the "chiral pool", being inexpensive in the L-form (but available if necessary as the D enantiomers), structurally varied and chemically versatile1, they are useful starting materials for chiral reagents, auxiliaries and ligands2. Any high-yielding transformation of an (-amino acids which proceeds without racemization is thus of potential importance, especially if it generates another reactive center and may be applied to the s…     

Novel Phenomenon of Oxygen-to-oxygen Silyl Migration in Directed Aldol Reaction

The phenomenon of migration of the silyl groups from α-oxygen to β-oxygen in sodium aldol reaction was observed for the first time in this paper.     

大孔吸附树脂处理含磺胺废水的研究

利用大孔吸附树脂处理含磺胺废水。实验表明，DRHⅢ树脂对磺胺具有良好的吸附－解吸效果。原废水中磺胺浓度约为17.2g/L,COD约为13750mg/L，经树脂吸附处理后，废水中COD去除率约86％，磺胺的吸附率88．2％，树脂的解吸率为97．5％，磺胺的回收率约86．0％，其纯度达99．8％。在废水有效处理的同时实现了废物资源化，具有良好的环境效益和较高的经济效益。     

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。