APPLICATION OF MSW-X_α METHOD WITH OVERLAPPING ATOMIC-SPHERE TO IONIZATION POTENTIALS FOR SOME PLANAR ORGANIC MOLECULES

Application of multiple scattered-wave X_α method with overlapping atomic-sphere to ionization potentials is reported for benzene, pyridine, pyrazine, pyrrole and imidazole. The calculated results show that the orbital charges in the intersphere region are non-negative and the energy levels get improvements in orderings.     

A new type of two-dimensional packed + capillary column GC system. I. Theory

Summary To match the need of high efficiency capillary column (plate number N₂, Plate height H₂ and carrier gas linear velocity U₂), a new high efficiency packed column (N₁, H₁ and U₁) at high carrier gas velocity with small capacity factor has been developed in the light of theoretical discussion of factors effecting the column efficiency utilization ratio.     

分子筛模型中非骨架离子位置的研究

从理论上研究了非骨架阳离子可能的分布位置．计算了分子筛晶体基本结构单元在整个空间的静电势分布，找出空间中静电势的各个极小点．在静电势最低点逐个放置钠离子，优化，重新计算模型分子筛的电势分布．研究了阳离子放置过程中静电势变化的趋势．     

Evaluation of a purge-and-trap injection system for capillary gas chromatography-microwave induced plasma-atomic emission spectrometry for the determination of volatile selenium compounds in water

A method is presented for the selective determination of the volatile selenium species dimethylselenide and dimethyldiselenide, using a commercially available purge-and-trap injection system coupled to capillary gas chromatography-microwave induced plasma-atomic emission spectrometry. The efficiency of the purging step was evaluated and the parameters affecting the purge and trap processes were optimized. The method was applied to the determination of volatile selenium compounds in lake water. Relative detection limits of 2ng/l for dimethylselenide and dimethyldiselenide, corresponding to an absolute detection limit of 10 pg, were achieved.     

毛细管电泳安培检测法在中草药分析中的应用

由于毛细管电泳安培检测法(CE-AD)具有高的分离效率和低的检测限的优势,现已在分析科学的各个领域,特别是在药物行业中得到广泛应用。中草药的研究在我国医药事业中占有重要的地位,采用CE-AD分离并检测中草药中有效成分对于促进中草药的药理药效研究及中草药的定量分析和质量监测等有重要意义。本文综述了CE-AD在中草药及中药复方制剂中有效成分分析中的应用,评述了该法与其他分离分析方法相比在中草药分析中的优越性,并对CE-AD在中草药分析中的发展进行了展望。     

胺、醇、醚类化合物电离能的自相关拓扑研究

原子的染色序数 fi 定义为 :fi=gi·xi,式中 gi 为原子i在分子中的序数 ,xi 为其染色系数 .基于fi 建立改进的原子序数自相关拓扑指数mF ,其中的1F对烷烃及其衍生物具有良好的结构选择性 .使用第一电离能 (Ip)与0 F ,1F的数量关系模型对 32种脂肪族胺、醇、醚进行估算、预测 ,结果令人满意     

Analysis of dinitrofluoranthenes by high resolution capillary gas chromatography/mass spectrometry

This paper reports the retention indices of eighteen of the possible twenty-five dinitrofluoranthene isomers.     

Coupling between polymer adsorption and colloidal particle aggregation

Studies of the adsorption of high molecular weight polymers on colloidal latex and silica particles and their subsequent flocculation were carried out. Neutral polyethylene oxide samples with both a narrow and a broad molecular weight distribution were used together with low charged cationic copolymers. The influence of the particle concentration and polymer dose on the flocculation were systematically investigated under quiescent conditions.Equilibrium bridging only occurred with polyelectrolyte, even in very dilute suspensions, at high particle coverage. In contrast to this, non-equilibrium bridging occurred with both neutral polymer and polyelectrolytes but only for more concentrated suspensions and small amounts of adsorbed polymer. Polymer adsorption in dilute suspensions, which did not show particle aggregation was measured an electrophoretic technique. In more concentrated suspensions, where flocculation takes place, we found that aggregation prevents further polymer adsorption and induces both an excluded volume and a surface effect. The consequences on the shape of the isotherms differ according to the aggregation mechanism.A significant decrease of the amount, , of adsorbed polymer is observed with non-equilibrium bridging. When both mechanisms simultaneously contribute to the aggregation, the value of depends on their relative importance. In the intermediate range of copolymer dose their respective contributions are critically sensitive to the details of the mixing step and stirring, leading to non reproducible experimental results.     

非水介质毛细管电泳电导检测舒血宁片中槲皮素含量

以甲醇：水＝70：30的体系为分离介质，柠檬酸－三（羟甲基）氨基甲烷（Citric acid-Tris)为支持电解质，使用电导检测，对槲皮素及其制剂舒血宁片进行了毛细管电泳分离检测，对电泳介质的种类、浓度、表观pH值以及操作电压和进样时间对分离的影响进行了研讨，并对分离检测机理进行了探讨。建立的测定槲皮素的方法的线性范围为：8．0－160．0mg/L；峰面积的RSD（n=6)为1．7％，检出限为1．0mg/L；样品加标回收率为92．8％－98．2％。