一种新型硝化抑制剂的毛细管电泳与电色谱分析比较

本研究采用毛细管电泳与电色谱两种方法,在优化分离条件下将3,5-二甲基吡唑新型硝化抑制剂与土壤样品中的其它成分进行分离。通过比较其检出限及标准工作曲线证明:两种方法定量准确度相近,但毛细管电色谱法在实际样品的分离中具有明显的优势,是进一步研究该新产品的较好的分离分析方法。     

纳米二氧化硅颗粒的制备及其在加压毛细管电色谱中的应用

为了考察小粒径固定相在色谱分析中的特性,以Stober法为基础,以86.5%乙醇(V/V)作为反应溶剂,加入0.2 mol/L四乙氧基硅烷、2.0 mol/L,氨水制得 517 nm无孔二氧化硅颗粒,并将其用高压匀浆法填充,制得毛细管色谱柱.以加压毛细管电色谱 (pCEC)为分析平台,采用乙腈-水为流动相,探讨该硅胶色...     

Analysis of Adsorbate–Adsorbate and Adsorbate–Adsorbent Interactions to Decode Isosteric Heats of Gas Adsorption

A qualitative interpretation is proposed to interpret isosteric heats of adsorption by considering contributions from three general classes of interaction energy: fluid–fluid heat, fluid–solid heat, and fluid—high‐energy site (HES) heat. Multiple temperature adsorption isotherms are defined for nitrogen, T=(75, 77, 79) K, argon at T=(85, 87, 89) K, and for water and methanol at T=(278, 288, 298) K on a well‐characterized polymer‐based, activated carbon. Nitrogen and argon are subjected to isosteric heat analyses; their zero filling isosteric heats of adsorption are consistent with slit‐pore, adsorption energy enhancement modelling. Water adsorbs entirely via specific interactions, offering decreasing isosteric heat at low pore filling followed by a constant heat slightly in excess of water condensation enthalpy, demonstrating the effects of micropores. Methanol offers both specific adsorption via the alcohol group and non‐specific interactions via its methyl group; the isosteric heat increases at low pore filling, indicating the predominance of non‐specific interactions.     

动态磁涂覆混合纳米固定相毛细管电色谱中芳香酸的输运特征研究

推导了芳香酸在动态磁涂覆混合纳米固定相开管毛细管柱中等度洗脱和二元台阶梯度洗脱条件下的输运方程, 考察了其在该色谱柱上的保留特征. 结果表明, 等度洗脱时, 电渗流方向及大小随着两种固定相配比的改变而改变, 溶质的容量因子与弱阴离子交换固定相和反相固定相比例(Fe₃O₄@SiO₂-NH₂︰Fe₃O₄@SiO₂-C₁₈)之间具有良好的线性关系, 拟合后相关系数大于0.9166. 二元台阶梯度洗脱条件下, 溶质的迁移时间可以通过其在等度洗脱条件下的洗脱时间加以预测. 溶质在经磷酸缓冲液浓度、有机调节剂浓度和pH值台阶梯度洗脱后, 其预测保留时间和实际保留时间之间的相对误差分别小于8.0%, 10%和5.8%. 构建的系统在优化的色谱条件下对水提天麻进行了分离, 其主要成分柠檬酸的保留时间预测值与实际值之间相对误差为11%.     

Analysis of the Triglycerides and the Free and Derivatized Fatty Acids in Fish Oil by Capillary Electrochromatography

Capillary ElectroChromatography (CEC) on a fused silica capillary column (40 cm L × 100 μm i.d.) packed with 3 μm octadecylsilica (ODS) was evaluated for the analysis of the triglycerides and their fatty acids in fish oils, and more especially in the oil of Moroccan Sardinia pilchardus. The very high complexity of the lipids in fish oil is well illustrated by CEC with a nonaqueous mobile phase consisting of acetonitrile/isopropanol/n-hexane in the ratio 57/38/5 to which 50 mM ammonium acetate has been added. In order to unravel the complexity, the oil was hydrolyzed and the free fatty acids (FFAs), the methyl esters (FAMEs), and the phenacyl esters (FAPEs) were analyzed by CEC on the same column used for the analysis of the triglycerides. Isocratic elution was achieved with the mobile phase acetonitrile/50 mM MES pH 6 in ratio 9/1. The migration characteristics of FFAs, FAMEs, and FAPEs are compared. The analysis of FAPE derivatives has the advantage that quantification applying UV detection is possible and moreover that the number of double bonds in the fatty acid chains can be elucidated by measuring the UV abundance ratio 240/210 nm.     

微乳电动毛细管色谱法分离检测酱油中的氯丙醇

建立了微乳电动毛细管色谱分离3种氯丙醇的方法。以十二烷基硫酸钠(SDS)作为表面活性剂,系统考察了pH值、缓冲溶液类型和浓度、SDS浓度、助表面活性剂浓度、油相浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD),1,3-二氯-2-丙醇(1,3-DCP),2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳微乳缓冲液为1%(V/V)正庚烷,100 mmol/L SDS,10%(V/V)正丁醇和8 mmol/L磷酸二氢钠-硼砂溶液(pH 8.50),检测波长为192 nm,温度20℃,分离电压为15 kV。3种氯丙醇的线性范围为2.0×10-6～3.2×10-5 mol/L,相关系数大于0.996,检出限(S/N=3)为0.95～1.9μmol/L。酱油样品经乙醚液液萃取,萃取平均回收率为93.2%～103.0%,相对标准偏差小于6.5%。本方法应用于实际样品和加标后样品中三氯丙醇的检测,结果满意。     

毛细管胶束电动色谱在扁桃酸合成中的应用

扁桃酸是药物中间体,可以苯甲醛为原料在相转移催化剂作用下合成制得.为了选择最佳合成条件,提高扁桃酸的转化率,需要对合成过程中各组分的含量进行快速测定,及时指导最优合成条件的选择.产品扁桃酸中可能含有未反应的苯甲醛和副产品苯甲酸、苯甲醇等杂质.以往采用非水溶剂酸碱滴定分析法测定产品中扁桃酸的含量,但当产品中有苯甲酸等酸性物质存在时,会使测定结果偏高.由于待测样品中组分扁桃酸、苯甲酸酸性使沸点较高,     

Electrokinetic Potential of Particles in Suspensions and Donnan Equilibrium in a Thin Gel Film

The influence exerted by the thickness of a gel layer on the difference of the electric potentials of phases and on the distribution of the potential near the phase boundary are considered in terms of the classical theory of the Donnan equilibrium in a two-phase system constituted by a gel and an electrolyte solution. The results obtained make it possible to explain a number of experimental facts.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 224–228.Original Russian Text Copyright © 2005 by Bibik.     

Preparation of Polymeric Monolithic Column and Application to the Resolution of Aromatic Compounds in Capillary Electrochromatography

Polymeric monolithic capillary column-poly(GMA-co-EDMA-co-AMPS) was prepared and used for resolution of aromatic compounds ( benz alcohol, 2-phenylethanol, toluene, ethylbenzene ).     

Capillary Electrochromatography as a Method Development Tool for the Liquid Chromatographic Separation of DUP 654 and Related Substances

Capillary Electrochromatography (CEC) offers a rapid, economical, and efficient means for resolving nonionic compounds in the reversed phase mode on octadecylsilane (ODS) columns. A CEC optimization on a Hypersil ODS capillary column was employed to identify a suitable mobile phase for the pressure-driven (reversed phase ODS) separation of the anti-inflammatory 2-phenylmethyl-1-naphthol (DUP 654), and its related substances. The proportions of mobile phase modifiers methanol, acetonitrile, and water as well as pH were employed as variables in a stacked mixture design. Comparable response surface profiles were obtained for the CEC separations at pH 4 and pH 8. However, subtle differences were evident in the quality of separations obtained in the liquid chromatographic (LC) mode when using a specially-prepared column packed with exactly the same stationary phase as used in the CEC experiments. A mapping of the response surface for separations on a commercially available Hypersil ODS LC column revealed obvious differences. The differences indicate that the transfer of ODS based separation methods between CEC and LC involves more than simply transferring the conditions from one mode to the other.     

Intersection Point Rule for the Retention and Mobile Phase Composition of the Homologues in Reversed-Phase Capillary Electrochromatography

Capillary Electrochromatography is a kind of micro-separation techniques newly developed in resent years. It is of both high selectivity of HPLC and high efficiency of capillary electrophoresis. This subject is being studied widely now. However, still many imperative problems need to be explored in the respect of retention rule. In this paper,based on the retention rule in RP-HPLC, the intersection point rule for the retention of homologues and the volume fraction of the organic modifier in the mobile phase in the reversed-phase capillary electrochromatography (RP-CEC) was derived, and was testified by a lot of experimental data.     

毛细管电色谱中双电层叠加的研究

通过流动相中电解质浓度对毛细管电色谱柱效能的流动相平均线速度的影响，研究了ＣＥＣ中双电层叠加现象。提出选择合适电解质组成的浓度及在制备色谱柱过程中避免细小和破碎的固定相颗粒进入柱中，以有效地减小双电层叠加作用。     

胶束电动毛细管色谱法测定大气中的甲醛、乙醛和丙酮

用胶束电动毛细管色谱法同时测定了大气污染物甲醛、乙醛和丙酮。样品经２,４－二硝基苯肼衍生。采用４７ｃｍ（到检测窗口４０ｃｍ）×５０μｍｉ．ｄ．毛细管柱,以５０ｍｍｏｌ／Ｌ十二烷基硫酸钠－２０ｍｍｏｌ／Ｌ四硼酸钠溶液（ｐＨ９．００）为操作缓冲溶液,电压３０ｋＶ,检测波长２１４ｎｍ,７．５ｍｉｎ内甲醛、乙醛和丙酮的２,４－二硝基苯腙衍生物可获得良好的分离。用峰面积定量,线性范围为０．０１～０．５ｇ／Ｌ,最小检出浓度均为２ｍｇ／Ｌ,变异系数在８．７％以内。     

一种新型甘油三酯吸附剂的制备及其对血清中甘油三酯的吸附性能研究

合成了一种新型的甘油三酯吸附剂-磺化羟乙基化交联壳聚糖，用其对血浆中甘油三酯进行吸附．实验结果表明，该吸附剂最高可使血清中的甘油三酯降低76．9％（每克树脂吸附量为6．25mg），而对血清中总蛋白（TP）的吸附较少．     

Advances in the Use of Cyclodextrins as Chiral Selectors in Capillary Electrokinetic Chromatography: Fundamentals and Applications

Capillary electrokinetic chromatography is generally recognized as a versatile and robust capillary electromigration technique for the separation of enantiomers. In this mode, one or more chiral selectors are added to the background electrolyte acting as pseudostationary phases. Within the various chiral selectors that have been applied to enantioseparations in capillary electrokinetic chromatography, cyclodextrins are by far the most often used selectors because of their versatility, structural variety and commercial availability. This is reflected in the large number of applications of cyclodextrins to analytical enantioseparations that have been reported between January 2012 and July 2016, the period of time covered by this review. Many of these applications cover aspects of life sciences such as drug analysis, bioanalysis or food analysis. Despite the large number of commercially available cyclodextrins, new derivatives have been developed in order to achieve altered enantioselectivities or to further broaden the application range. Cyclodextrins have also been used to demonstrate the validity of theoretical models of electromigration as well as complex formation equilibria in enantioseparations. Finally, recent studies for an understanding of the molecular basis of the chiral recognition between cyclodextrins and the analytes are discussed.

     

复合功能超高交联吸附树脂对氨基萘酚磺酸的静态吸附热力学及动力学特征

吸附动力学;复合功能超高交联吸附树脂对氨基萘酚磺酸的静态吸附热力学及动力学特征;颗粒内扩散;     

Complimentary Role of Micellar Electrokinetic Capillary Chromatography and High Performance Liquid Chromatography in the Separation of Plant Phenolics

Abstract

A comparison was made between the efficiency of micellar electrokinetic capillary chromatography (MECC) and reversed phase high performance liquid chromatography (RP-HPLC) to separate a mixture of plant phenolics. Of a range of buffers 6 mM borate/10 mM phosphate/100 mM SDS at pH 8.5 was the most effective in separating a complex mixture of phenolics using MECC. Using this buffer the elution order and resolution was different from that obtained by HPLC using a reversed phase C18 column. These results illustrate how MECC and RP-HPLC are complimentary when examining complex mixtures such as those obtained from plant extracts. MECC using these conditions was applied to the examination of phenolics from leaf tissue of Eucalyptus margmata (jarrah).