Direct coupling of capillary supercritical fluid chromatography with double-focusing high resolution mass spectrometry

An integral restrictor interface with jet separator for coupling capillary column supercritical fluid extraction – supercritical fluid chromatography with high resolution mass spectrometry (SFE-SFC-MS) has been built and used for the analysis of a fatty acid ester, and of polymer additives with a wide range of masses. The mobile phase used was supercritical carbon dioxide; a flame ionization detector (FID) was used in parallel with the mass spectrometer. Different SFC-MS interface operating conditions, e.g. temperature, restrictor position, flow rate, and sample transfer conditions were optimized to obtain good sensitivity and separation for these applications. In addition, the sensitivity of measurements performed with the direct insertion probe and by SFC-MS interface have been compared.     

Improved Extraction Method and Chromatographic Separation of Ginsenosides from Ginseng Roots,Leaves and Ginseng Drug Preparations

A new extraction method for ginsenosides from ginseng roots, ginseng leaves and ginseng drug preparations by Sep-Pak C₁₈ cartridges has been studied. Ginsenoside extraction by Sep-Pak cartridges is a rapid, efficient, reproducible method. In addition, the extracts were analyzed by high performance thin layer chromatography (HPTLC) and reverse phase high performance liquid chromatography (HPLC). The major components of ginseng saponins were effectively separated using an ODS-120T column.     

特征线法在求解非线性液相吸附色谱模型中的应用

本文应用特征线法求解非线性液相吸附色谱分离过程模型，论述了特征线法的原理和步骤，讨论了时间步长和空间步长对模型数值解的影响，并用色谱分离甘露醇和山梨醇以及分离蔗糖和还原糖的实验进行验证，用特征线法计算的理论流出曲线与实验流出线吻合较好。本文还分折了模型中各个参数的灵敏度，结果表明：吸附等温方程Q＝Ci*／（ai＋biCi*）中参数ai比参数bi以及总传质系数ki有更高的灵敏度。     

Studies on separation mechanisms of biological molecules on a polyvinyl alcohol column

Summary The chromatographic separation mechanism on a polyvinyl alcohol (PVA) column in aqueous systems was explored utilizing several different types of compound such as polyethylene glycols, carbohydrates, pyrimidine and purine bases, fatty acids, monophosphate nucleotides and glycyl-peptides. Two types of separation mechanisms were found to occur for these substrates. The polyethylene glycols and the carbohydrates were eluted by size-exclusion chromatography. The retention behavior of the other substrates could be explained by the solvophobic theory, suggesting that the predominant separation mode was reversed-phase chromatography. The occurrence of reversed-phase chromatography was also indicated by the remarkable effect of the addition of ion-association reagents to the chromatographic system on the retention of the monophosphate nucleotides.     

高效液相色谱指纹图谱应用于地黄的研究

利用高效液相色谱建立了地黄的色谱指纹图谱。采用反相C1 8柱 (5 μm ,1 5 0mm× 4.6mm) ,流动相甲醇∶水 (V V =5∶95 ) ,检测波长为 2 80nm ,流速 1 .0mL min进行实验。根据相对保留值和相对面积值对色谱指纹图谱进行分析对比研究 ,建立了控制地黄药材质量的新方法。该法为中药样品的鉴定提供了较全面的信息 ,并为HPLC在复杂组分的样品分析领域开拓了新的应用途径。     

High performance liquid chromatographic studies on lanthanides, uranium and thorium on amide modified reversed phase supports

The retention behavior of uranium, thorium and lanthanides has been investigated with amide modified reversed phase C₁₈ supports using α-hydroxy isobutyric acid (α-HIBA) as the mobile phase. Four structurally different amide moieties namely, 4-hydroxy-N,N-dihexyl butyramide (4HHBA), 4-hydroxy-N,N-di-2-ethylhexylhexanamide (4HEHHA), bis(N,N,N′,N′-2-ethylhexyl)malonamide (B2EHM) and N-methyl-tris(dihexylcarbamoyl-3-methoxy)pivolamide (MTDCMPA) have been synthesized and studied. Among the various amide coated columns, the supports modified with 4HHBA, B2EHM and MTDCMPA exhibit an interesting retention for uranium and thorium, which is different from 4HEHHA modified support. The retention time for uranium and thorium increases with increasing amide concentration for 4HHBA, B2EHM and MTDCMPA supports, while the same decreases with increasing 4HEHHA content. However, the separation factor for uranium and thorium is greater on a 4HEHHA support, compared to an unmodified C₁₈ column, reflecting the amide's preferential complexation of uranium over thorium.Columns modified with 4HHBA, B2EHM and MTDCMPA exhibit relatively higher retentions for lanthanides. However, MTDCMPA modified support shows a different elution profile for lanthanides compared to 4HHBA, and B2EHM modified columns. Individual separations of heavier lanthanides, i.e., from gadolinium to lutetium also have been achieved using 4HHBA and B2EHM modified supports.The influence of modifier content, mobile phase concentration and its pH on the retention of metal ions has also been studied. Based on these investigations, an efficient high performance liquid chromatographic method (HPLC) has been developed for the rapid separation of uranium from thorium as well as for the individual separation of heavier lanthanides.     

一种新型双亚胺吡啶铁系催化剂的乙烯低聚研究

线性α 烯烃广泛地应用于洗涤剂、增塑剂、润滑油等精细化学品的合成以及作为共单体制备线性低密度聚乙烯 (ＬＬＤＰＥ) .目前工业上主要是应用ＳＨＯＰ法[1] 、Ｃｈｅｖｒｏｎ工艺和Ａｍｏｃｏ工艺[2 ] 通过乙烯低聚制备 .近些年发展起来的新型高活性后过渡金属乙烯低聚催化剂能够高选择性地制备线性α 烯烃[3 ,4] .Ｂｒｏｏｋｈａｒｔ等[4] 的研究表明 ,对于双亚胺吡啶铁系乙烯聚合催化剂而言 ,配体上苯基的邻位取代基位阻减小可以实现乙烯低聚 ,并具有高活性、高选择性以及理想的低聚产物分布 .本文的工作是从配体的空间位阻效应对催化剂…