基于遗传算法的手性毛细管电泳分离中多指标同时优化

将功效函数法结合遗传算法用于碱性药物肾上腺素的手性毛细管电泳的多指标同时优化.以均匀设计安排了4因素(电解质浓度、pH值、手性试剂浓度和分离电压)6水平实验,建立了峰分离度、迁移时间和灵敏度与实验因素间的多元线性回归方程.为获得毛细管电泳评价指标的同时优化,采用Derringer功效函数法,建立了总功效函数与实验因素的定量关系.采用实数编码的遗传算法搜寻总功效函数的最大值,获得了多个优化分离条件,在这些分离条件下得到的总功效函数与均匀试验设计中最佳条件相比,平均提高了10.4%,获得了三指标同时优化的结果.     

粒子群算法优化中药化学成分的毛细管电泳分离条件

建立了一种基于粒子群优化算法的毛细管电泳条件辅助优化方法。以丹参为研究对象,将改良的色谱指数方程用于评价酚酸类成分的电泳分离性能,用粒子群优化算法对分离条件进行全局寻优,获得最佳的区带电泳分离条件(5.0 mmol/L硼砂,18.5 mmol/L磷酸二氢钠,6.1%乙腈,运行电压18.2 kV)。为进一步改善分离,在所获优化条件下添加50.0 mmol/L SDS,在胶束电动毛细管色谱分离模式下使酚酸类成分(原儿茶醛、丹参素、丹酚酸B等)得到更好分离。本方法准确可靠,可推广应用于其他复杂化学体系的毛细管电泳分离条件优化。     

食品中金属离子的微波消解-高效毛细管电泳法测定

采用微波消解－高效毛细管电泳法测定食品中的K，Na,Ca,Mg等金属离子，考察了微波消解的最佳条件；研究了背景电解质，缓冲液pH值，操作温度和分离电压等对电泳分离中运行电流，电渗迁移率，峰形等参数的影响，确定了金属离子电泳分离的最佳实验条件；该法已应用于食品中金属离子的测定，并与原子吸收法进行比较，得到满意的结果。     

毛细管电泳-电致化学发光法测定土壤中的多抗霉素B

以稀土铕离子(Ⅲ)掺杂的类普鲁士蓝膜(Eu-PB)修饰铂电极为工作电极,采用毛细管电泳-电致化学发光法(CE-ECL)对土壤中的多抗霉素B进行检测.分别对毛细管电泳分离条件和电致化学发光检测条件进行优化,并探讨了体系产生电致化学发光的机理.在优化实验条件下,多抗霉素B可在4 min内得到分离,其ECL强度值与多抗霉素B...     

毛细管电泳分离几种神经递质的研究

研究了不同毛细管预处理方法对组胺、5-羟色胺及儿茶酚胺类神经递质电泳分离的影响，采用优化的毛细管预处理方法及电泳分离条件基线分离了组胺、5-羟色胺、去甲肾上腺素和肾上腺素。利用多巴胺和5-羟色胺在毛细管内壁吸附效应的不同，对电泳淌度极为相近的多巴胺和5-羟色胺进行了分离和鉴定。以PC22细胞为研究对象，证实了该细胞中所含大量神经递质是多巴胺，不是5-羟色胺。     

毛细管电泳在手性分离中的应用及进展

本文评述了近年来毛细管电泳在手性分离中的应用及进展，介绍了毛细管电泳分离手性对映射的数学模型、五种不同的分离模式及机理、七种常用的手性选择性类型及其在药学、环境和生命科学中的应用、研究中需优化的操作参数及其发展方向。     

金纳米微粒修饰毛细管电泳分离蛋白质的研究

报道了金纳米微粒(Au NP)修饰毛细管电泳分离蛋白质的方法.采用物理吸附法将Au NP修饰在熔融石英毛细管内表面,制备成Au NP修饰毛细管.探讨了修饰剂Au NP的浓度对电渗流及蛋白质分离的影响.结果表明,Au NP修饰的毛细管能有效地抑制电渗流及蛋白质在毛细管内壁上的吸附,提高分离效率.在优化的实验条件下,实现了...     

高效毛细管电泳分离的优化策略

本文提出一种新的优化策略，综合分析表面活性剂浓度、缓冲液ＰＨ值、有机添加剂浓度，缓冲溶液浓度及操作电压等实验因素对高效毛细管电泳分离的影响，用多种优化目标函数考察分离度和峰分布均匀性。     

橙皮甙、柚皮甙、橙皮素和柚皮甙元4种物质的毛细管电泳分离及测定

通过优化缓冲溶液pH和浓度、分离电压和进样时间等条件,建立了橙皮甙、柚皮甙、橙皮素和柚皮甙元4种物质的毛细管电泳分离分析方法.在优化的条件下10 min内实现了4种物质的毛细管电泳分离.橙皮甙、柚皮甙、橙皮素和柚皮甙元4种物质分别在0.03～0.80、0.03～0.85,0.02～0.60和0.02～0.65mg/mL浓度范围内和峰电流成线性关系,检出限分别为0.007、0.006、0.004和0.005 mg/mL.方法用于分析模拟样品得到满意的结果,有望用于实际样品分析.     

寡糖的毛细管电泳分析

多种寡糖经α－萘胺衍生化后，用硼砂作为电泳介质，实现了高效毛细管电泳分离。比较了毛细管区带电泳和胶束毛细管电动色谱分离寡糖α－萘胺衍生物的电泳行为，对影响分离度的诸因素进行了考察，选择了最佳分离条件。     

Method development and validation for the chiral separation of peptides in the presence of cyclodextrins using capillary electrophoresis and experimental design.

The present study describes the application of statistical experimental design to the optimization of enantioselective separations of peptides in capillary electrophoresis in order to obtain optimal operating conditions for routine work. Hydroxypropyl-beta-cyclodextrin was used as chiral selector and Ala-PheOMe as model peptide. The experiments were performed according to a face centered cube response surface experimental design for obtaining information how the factors such as concentration of the chiral selector, pH, buffer concentration and voltage affected the two response goals, resolution and analysis time. In order to achieve the simultaneous optimization of these two major electrophoretic performance goals for efficient and fast separation, the Derringer desirability functions were tested. While in the predefined experiments the analysis time for baseline separation was 25 min the desirability functions proposed a CE method, which diminished the analysis time and permitted the complete separation of the peptide enantiomers within 9 min.     

Interinstrumental Transfer of a Chiral Capillary Electrophoretic Method: The Use of Robustness Test Information to Overcome Differences in Detector and Data-Handling Specifications

Capillary electrophoresis has been widely used as chiral separation technique, applying chiral selectors that are added to the background electrolyte. The advantages of capillary electrophoresis as separation technique are its flexibility, low cost, and high separation efficiency. This study is part of a research project, where guidelines are defined to facilitate interinstrumental method transfer of capillary electrophoretic methods, which is one of the major drawbacks of capillary electrophoresis. Another drawback is the lower sensitivity compared to liquid chromatographic methods. Improving and maintaining the sensitivity are the reason why focus should be put on the interinstrumental differences between detector settings. The aim of this study was to determine when adaption of the detector settings during interinstrumental method transfer was needed. The chiral separations of two betablockers were selected as case studies. The influence of detector parameters, such as data acquisition rate, bandwidth, and filter, on sensitivity responses, such as peak area, height, and width, was evaluated by means of robustness tests performed on two capillary electrophoresis instruments. The statistically significant parameters were identified and non-significance intervals determined. To maintain or optimise the obtained sensitivity, the information gathered from the robustness test was further incorporated in guidelines developed to facilitate interinstrumental analytical method transfer of capillary electrophoretic methods.     

Optimization and Parameter Study for Chiral Separation by Capillary Electrophoresis

Orthogonal design and uniform design were used for the optimization of separation of enantiomers using 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD) as a chiral selector by capillary zone electrophoresis. The concentration of DM-β-CD, buffer pH, running voltage, and capillary temperature were selected as variable parameters, their different effects on peak resolution were studied by the design methods. It was concluded that orthogonal design offers a rapid and efficient means for testing the importance of individual parameters and for determining the optimum operating conditions. However, for a large number of both factors and levels, uniform design is more efficient. The effect of addition of methanol and citric acid buffer on the separation of enantiomers was also examined.     

Enantioseparation of 2-O-beta-D-glucopyranosyl-2H-1,4-benzoxazin-3(4H)-one and its 7-chloro-derivative by capillary zone electrophoresis using native and substituted beta-cyclodextrins as chiral additives

Efficient, rapid and inexpensive methods were established for the chiral separation of two glucopyranosyl compounds from plant extracts, by capillary zone electrophoresis (CZE). Baseline separation was achieved for both compounds. Several native cyclodextrins and their derivatives were tried as chiral selectors. CM-beta-CD and HP-beta-CD (with addition of acetonitrile in the buffer) gave rise to optimal chiral separation for the two compounds, respectively, each within a few minutes. The effects of several parameters on the chiral separation were studied.     

Fast enantiomeric separation with vancomycin as chiral additive by co-electroosmotic flow capillary electrophoresis: increase of the detection sensitivity by the partial filling technique

A fast and sensitive method is described by using vancomycin as a chiral additive for enantiomeric separation by capillary electrophoresis (CE). In order to overcome disadvantages associated with use of vancomycin as chiral additive in CE, several strategies including the dynamic coating technique, the co-electroosmotic flow technique, and the partial filling technique were employed sequentially in this method. Using the polycationic polymer hexadimethrine bromide (HDB) as a buffer additive, the capillary wall was dynamically coated with a thin film formed by the adsorbed HDB. Consequently, the adsorption of vancomycin onto the capillary wall was minimized via electrostatic repulsion between the coating of the capillary wall and the vancomycin molecule. In addition, the reversed electroosmotic flow (from cathode to anode) produced by the positively charged capillary wall migrates in the same direction of negatively charged analytes (co-electroosmotic flow electrophoresis). Thereby the electrophoretic mobility of negatively charged analytes were drastically accelerated leading to a short separation time of less than 3.4 min. The separation time was further reduced by the use of a short-end-injection technique. For example, the analysis time was achieved by as short as 55 s for a baseline separation of dansyl-alpha-amino-n-butyric acid. Concurrently, the partial filling technique was used to avoid the loss of detection sensitivity caused by the presence of vancomycin in the running buffer. The effect of several parameters, such as HDB concentration, buffer pH, plug length of the chiral selector, concentration of the chiral selector and applied voltage, on enantioselectivity were investigated toward optimization. Besides the advantage of a very short separation time, the method is characterized by high detection sensitivity, high selectivity, and high efficiency.     

Chiral separation of unmodified amino acids with non-aqueous capillary electrophoresis based on the ligand-exchange principle

A ligand exchange mechanism in non-aqueous capillary electrophoresis was employed for the separation of eight unmodified amino acids using chiral complexes of copper(II) with L-proline and L-isoleucine. The electrophoretic medium consisted of 25 mM ammonium acetate and 1 M acetic acid in methanol. We were able to completely separate the enantiomeric pairs of each of the investigated racemic amino acids. We also report the optimization of the separation parameters, such as pH*, composition of the complex, and concentration of the complexing agents.     

毛细管电泳在手性分离中的应用进展

本文以手性选择剂为线索综述了近五年来毛细管区带电泳和胶束电动毛细管电色谱在手性药物拆分中的应用进展,列举了部分手性药物拆分实例.     

Enantioselective Separation of Basic Drugs by CE with Polygalacturonic Acid as a Novel Chiral Selector

Polygalacturonic acid, a linear high molecular weight homopolysaccharide was investigated as a chiral selector in capillary zone electrophoresis for the separation of enantiomers of basic drugs. The choices of running buffer pH and concentration of chiral selector were found to be important for the improvement of enantioselectivity. The effects of background electrolyte concentration and the capillary temperature on the separation were also examined. Enantioseparations were carried out in the acidic conditions using 1.5% polygalacturonic acid (w/v) in a 40 mM phosphate buffer under an applied voltage of 15 kV. The optimization of these separations was dependent on the nature of the analytes and could be achieved by the proper choice of experimental conditions. A brief mechanism of enantiorecognition by polygalacturonic acid was also given.     

Investigation of Induced Peak Phenomenon in Capillary Electrophoresis with Electrochemiluminescence Detection

Abstract

Induced peak phenomenon in capillary zone electrophoresis with electrochemiluminescence detection for chiral separation of racemic phenylalanine mixture employing sulfated‐β‐cyclodextrin as chiral selector and acetonitrile as organic additive in the separation buffer was observed. Various experimental parameters influencing the intensity and the position of the induced peak were systematically investigated to find out the truth of the induced peak. Based on the experimental evidence, a reasonable mechanism involved in the formation of the induced peak was proposed. We found out the induced peak resulted from physical interactions between the components in the separation buffer and the injected sample during the electromigration process rather than chemical complexation interactions. Furthermore, suggestions to avoid the appearance of induced peak in capillary zone electrophoresis with electrochemiluminescence detection for chiral separations were presented.