强阳离子交换整体电渗泵流量影响因素研究

采用丙烯酸,2-丙烯酰胺-2-甲基丙磺酸为功能单体,N,N’-亚甲基双丙烯酰胺为交联剂,正十二醇、1,4-丁二醇及二甲基亚砜为致孔剂,偶氮二异丁腈为引发剂在原位聚合,制备出了以丙烯酰胺类强阳离子交换整体柱为核心的电渗泵.在乙腈-磷酸盐二元流动相体系下,考察了驱动电压,有机调节剂,盐浓度,pH对该泵流量的影响.流量与驱动...     

微电渗流毛细管原位柱中流动相组成对电渗流的影响

采用原位聚合的方法合成了一种新型微电渗流毛细管电泳原位柱。考察了不同有机调节剂种类和浓度 ,pH对电渗流的影响 ,在 pH值 2 .3～ 9.8范围内 ,电渗流小于 19.6× 10 -10 m2 V-1s-1。当有机调节剂浓度从 6 0 %增加到 90 %时 ,电渗流仅从 6 .6× 10 -10 m2 V-1s-1增大到 4 8.9× 10 -10 m2 V-1s-1。结果表明 ,此类微电渗流柱在电色谱分离模式下电渗流保持在较低水平     

吉培福林对映体的毛细管电色谱分离

在碱性条件下合成了单(六-氧-甲基丙烯酸酯)-β-环糊精(CD),以甲基丙烯酸甘油酯(GMA)和单(六-氧-甲基丙烯酸酯)-β-CD为单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,2-丙烯酰胺基-2-甲基-1-丙磺酸(AMPS)用来产生电渗流,正丙醇和1,4-丁二醇为制孔剂,偶氮二异丁腈(AIBN)为引发剂,在内径100 μm的毛细管内原位聚合制得了手性毛细管电色谱整体柱.采用制得的手性整体柱,在加压毛细管电色谱(pCEC)模式下,对吉培福林对映体进行手性分离,考察了流动相配比、背景电解质pH值、柱温和分离电压等对分离的影响.在缓冲溶液为5 mmol/L NaH2PO4-Na2HPO4(pH 2.5)、运行电压20 kV、毛细管温度15 ℃条件下,16 min内成功分离了吉培福林对映体,其分离度为1.53.     

整体柱电渗泵的流量控制研究

通过制备丙烯酸酯类整体柱电渗泵,在nL/s～μL/s级流量范围内,考察了操作电压、有机调节剂浓度、盐浓度、pH值等对流量的影响.实验结果表明,在3～17 kV范围内,操作电压与流量呈线性关系,线性相关系数达到0.9991;当选择乙腈(0.55～0.8 mmol/L浓度范围)与MES缓冲溶液混合作为输运溶液时,电渗泵流量随有机调节剂浓度增加而呈减小趋势,且当盐浓度在0.5～2.0 mmol/L范围内逐渐增加时,电渗泵流量逐渐减小;pH值在3～9时,电渗泵流量基本不变.结果表明, 丙烯酸酯类整体柱电渗泵较ODS柱电渗泵具有一定优势.     

氨基安替比林MIP-CEC整体柱的制备及电色谱性能研究

以氨基安替比林为模板分子,在内径100 μm的石英毛细管内采用原位聚合法制备了分子印迹毛细管整体柱,以电色谱模式分离了氨基安替比林及其结构类似物安替比林,在乙腈(体积分数15%)-磷酸二氢钠缓冲液(5 mmol/L)作为流动相(pH 7.0)条件下,18 min内完成分离,分离因子为1.37.考察了缓冲液中乙腈含量、pH值、离子强度对电渗流、溶质保留时间及分离因子的影响,探讨了整体柱识别机理.     

1 μm硅胶颗粒固定相的加压电色谱分离性能

制备了1 μm无孔硅胶颗粒。通过电动填充法得到总长度为45 cm(固定相填充长度为20 cm)、内径为100 μm的毛细管色谱柱。以乙腈-水体系作为流动相,详细考察了碱性化合物在该色谱柱上的加压电色谱(pCEC)分离性能,讨论了流动相比例、缓冲液浓度、pH值及操作电压等因素对分离的影响。实验结果表明,裸硅胶柱在乙腈-水体系分离碱性样品中表现出典型的反相色谱分离性能;缓冲液浓度的改变则对分离影响不大。当pH值改变时,碱性化合物的解离程度发生变化,它们与固定相之间的作用力发生变化,使得分离度发生相应的变化。分离柱效随施加电压的增加而增加,在1 kV电压下,裸硅胶柱对邻甲苯胺的柱效为35000理论塔板/m。     

磺丁基醚-β-环糊精修饰毛细管电色谱拆分地平类药物对映体

采用甲基丙烯酸缩水甘油酯原位聚合物基质,将磺丁基醚-β-环糊精修饰到毛细管内壁,制得了一种毛细管电色谱手性柱(SECDP),并通过红外光谱(IR)和扫描电子显微镜(SEM)表征了其结构.磺酸基可提供足够稳定的正向电渗流(EOF),基于磺丁基醚-β-环糊精在固定相和流动相中的协同作用,通过优化手性添加剂浓度、pH值、施加电压、温度及有机调节剂含量等条件,利用该开管电色谱柱拆分了氨氯地平、尼莫地平和尼卡地平等10种地平类手性药物对映体.优化的流动相组成为20 mmol/L NaH2PO4(pH=4.0),含4.0 mmol/L磺丁基醚-β-环糊精,乙腈的体积分数为10%~25%,施加电压15~25 kV,温度为15℃,电动进样2 kV×5 s,检测波长为236 nm.在上述条件下,分离度(RS)可达3.62,柱效达61011块/m,分析时间一般为6~15 min.基于色谱分离数据,探讨了相关的手性分离机理.     

甲基丙烯酸基质的毛细管电色谱整体柱的制备与应用

以甲基丙烯酸(MAA)为功能单体,同时又作电渗流改性剂, 乙二醇二甲基丙烯酸酯(EDMA)为交联剂,甲苯和异辛烷为致孔剂,Irgacure 1800为光引发剂,采用紫外光引发原位聚合反应制备出毛细管电色谱整体柱.对影响电渗流的因素如pH、乙腈含量及离子强度等进行了讨论.使用制备的整体柱在3种模式(加压电色谱、气压驱动和电色谱)下对7种中性物质(硫脲、苯、甲苯、乙苯、萘、联苯和菲)的混合物实现基线分离,同时还可实现酸性物质(邻羟基苯甲酸、苯甲酸、苯乳酸、扁桃酸)和碱性物质(苯胺、甲苯胺、乙酰基苯胺和N-甲基苯胺)的快速分离.     

混合固定相电中溶质的输运特征

 以离子交换和反相固定相构成的混合固定相电中 ,溶质迁移在受到疏水、离子交换作用的同时 ,对于带电溶质而言 ,还受到电泳迁移的影响。根据离子独立迁移原理 ,结合过程中的多种相互作用 ,得到了描述溶质表观迁移速率与其各形态迁移速率、各种相互作用之间相互关系的理论表达式 ;讨论了混合模式电中流动相的 pH及其中的有机调节剂浓度、混合固定相配比等对电渗流的影响及不同形态溶质在柱内的输运特征。结果表明 ,在电中采用混合固定相可以在较大的 pH和有机调节剂浓度范围内得到较强且稳定的电渗流。     

混合模式硅胶基质毛细管电色谱整体柱的制备及其电色谱性能研究

采用温和条件下的溶胶-凝胶技术,成功制备了阴离子交换-反相混合模式硅胶基质毛细管电色谱整体柱.通过调整反应液中不同前体的比例,优化了整体柱的制备条件.通过扫瞄电镜,对柱床进行了表征和分析.实验发现,所制备的整体柱电渗流的方向和大小可随流动相pH值的改变而改变,在酸性和中性条件下,具有从阴极流向阳极的电渗流;当流动相pH值升至约7.5时,电渗流方向发生了反转(由阳极流向阴极).在优化的实验条件下,用所制备的整体柱对所考察的酸性(中性)化合物实现了快速分离,并获得了高达160,000 N/m的柱效.     

Chiral separation of basic compounds on a cellulose 3,5-dimethylphenylcarbamate-coated zirconia monolithin basic eluents by capillary electrochromatography

Porous zirconia monolith (ZM) modified with cellulose 3,5-dimethylphenylcarbamate (CDMPC) was used as chiral stationary phase to separate basic chiral compounds in capillary electrochromatography. The electroosmotic flow behavior of bare and CDMPC-modified zirconia monolithic (CDMPC-ZM) column was studied in ACN/phosphate buffer eluents of pH ranging from 2 to 12. The CDMPC-ZM column was evaluated by investigating the influences of pH, the type and composition of organic modifier of the eluent on enantioseparation. CEC separations at pH 9 provided the best resolutions for the analytes studied, which are better than those observed on CDMPC-modified silica monolithic columns under similar chromatographic conditions. No appreciable decline in retention and resolution factors after over 200 injections, and run-to-run and day-to-day repeatabilities of the column of less than 3% indicate the stability of the zirconia monolithic column in basic media.     

Separation and determination of 10-hydroxy-2-decenoic acid in royal jelly by capillary electrophoresis

Summary The application of capillary electrophoresis (CE) to the separation and determination of the active ingredient, 10-hydroxy-2-decenoic acid, in royal jelly with direct on-column UV detection at 214 nm is described. Using a cathodic injection and anodic detection scheme, 10-hydroxy-2-decenoic acid (10-HDA) was separated and detected in less than 10 min in a fused silica capillary column with a phosphate buffer at pH 7.3 with an applied voltage of 20 KV followed by direct UV detection. The use of cetyltrimethylammonium bromide (CTAB) as electroosmotic flow modifier allows the rapid separation of 10-HDA from other constituents in royal jelly by reversing the direction of electroosmotic flow. The influence of organic solvents in the electrolyte on separation selectivity is also discussed.     

毛细管电泳法测定阿霉素脂质体药物中的微量硫酸根离子

建立了以硝酸钾作为背景电解质测定阿霉素脂质体药物中微量硫酸根离子的毛细管电泳分析法。考察了分离电压、背景电解质、电渗流改性剂浓度、pH值对分离测定的影响。结果表明,当毛细管长度为60 cm(有效长度51.5 cm)、分离电压为~15 kV、缓冲溶液采用20 mmol/L硝酸钾(pH 7.0)、电渗流改性剂采用0.4 mmol/L十六烷基三甲基氯化铵(CTAC)、检测波长为202 nm时,阿霉素脂质体破乳液中硫酸根离子和氯离子在3 min内得到了基线分离,硫酸根离子迁移时间和峰面积的相对标准偏差分别小于0.01%和1.0%,检出限为5 μg/L。用该方法对阿霉素脂质体样品中的微量硫酸根离子进行了分析测定,结果令人满意。     

Fast separations of chiral β-blockers on a cellulose tris(3,5-dimethylphenylcarbamate)-coated zirconia monolithic column by capillary electrochromatography

Cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) is an excellent chiral selector for enantioseparation of a wide variety of chiral compounds. The monolithic chiral columns are becoming popular in liquid chromatography and capillary electrochromatography. In this work, we present the fast separation of chiral β-blockers on a CDMPC-modified zirconia monolithic column by capillary electrochromatography (CEC). The porous zirconia monolithic capillary column was prepared by using the sol-gel technology and then zirconia surface modified with CDMPC. The enantioseparations were performed in reversed-phase (RP) eluents of a phosphate solution (pH 4.4) modified with acetonitrile or alcohol. The enantioseparations of a set of eight chiral β-blockers were achieved in less than one minute. Influences of the applied voltage, column temperature, concentration of acetonitrile and the type of alcohol as the organic modifier in the mobile phase, and sample injection time on enantioseparation were investigated. CEC separations at the applied voltage of 10 kV and 15 °C in the ACN-modified mobile phase provided the best resolutions for the analytes studied. Run-to-run and day-to-day repeatabilities of the column in the RP-CEC separation were less than 1 and 2%, respectively.     

毛细管硅胶基质整体柱的制备及其电色谱性能研究

采用热引发一步法制备了毛细管电色谱硅胶基质整体柱。通过使用表面活性剂(十二烷基磺酸钠)增加了反应液中两相之间的相互溶解,使得反应液最终成为均相溶液,实现了硅胶整体柱的均相聚合制备。所制备的均相硅胶整体柱内部结构更加均匀,大大提高了分离度。评价了该整体柱的电色谱性能,深入探讨了有机溶剂比例、pH值、电压以及温度等电色谱操作条件对电渗流、保留机理和柱效的影响。在该均相硅胶基质整体柱上成功地分离了9种中性物质(硫脲、苯、甲苯、乙基苯、正丙苯、萘、正丁基苯、芴和蒽)以及7种中性、酸性和碱性物质(硫脲、邻氨基酚、苯酚、苯、邻甲苯胺、α-萘胺和2,4-二氯苯胺)。该柱对硫脲的柱效超过110000塔板/m。     

十二烷基键合氧化锆填充电色谱柱的研究

以十二烷基键合氧化锆(C12-ZrO2)作为固定相,制备了填充毛细管电色谱(CEC)柱,较为系统地研究了流动相条件对电渗流的影响、填充CEC柱的稳定性、碱性与中性化合物的保留与流动相pH值和有机溶剂含量的关系。C12-ZrO2固定相填充CEC柱在pH3～11．7范围内具有极好的稳定性;利用磷酸盐与氧化锆表面之间较强的相互作用,能够有效解决传统硅胶键合烷基固定相在有机溶剂含量低的流动相条件下不稳定的问题;同时吸附磷酸盐的固定相表面使得在更宽的流动相pH值范围内CEC柱有足够的电渗流,进一步拓宽CEC的应用领域。     

爆炸残留物的毛细管电泳检测

1引言爆炸是恐怖袭击的常用手段。对痕量爆炸残留物进行高效检测,从而准确判断炸药的成分和种类,能够为侦破案件提供重要的线索和证据[1,2]。近年来,毛细管电泳技术初步显示了其在爆炸物检验方面的巨大潜力[3～6]。本实验基于毛细管电泳间接紫外吸收检测[7,8]和胶束电动色谱[9],建立了痕量爆炸残余物的系统分析检验方法,通过对爆炸瞬间产生的痕量     

Influence of mobile phase composition on electroosmotic flow velocity, solute retention and column efficiency in open-tubular reversed-phase capillary electrochromatography

The effects of some experimental parameters, such as the volume fraction and type of organic modifier in the mobile phase, and the concentration, type and pH of the buffer on the electroosmotic flow velocity, the retention behavior of test solutes, and the column efficiency have been investigated in capillary electrochromatography (CEC) using an open-tubular column of 9.60 microm I.D. with a porous silica layer chemically modified with C18 as stationary phase. The retention of a group of polycyclic aromatic hydrocarbons (PAHs) used as a test mixture varied significantly by changing the organic modifier content in the hydroorganic mobile phase according to the reversed-phase-like selectivity of the stationary phase. In addition, an increase in the percentage of organic modifier resulted in a slight increase in the linear velocity of the EOF. On the other hand, when the phosphate buffer concentration was increased over the range 1-50 mM, the electroosmotic mobility fell dramatically, the retention of the solutes decreased steadily, and the plate height showed a significant increase. The results obtained with phosphate, trishydroxymethylaminomethane or 2-morpholinoethanesulfonic acid as buffers were similar when pH remained constant. Optimization in CEC was essential to achieve further enhancement of separation performance, because the analysis time and separation resolution are essentially affected when varying operating parameters. Separations of seven PAHs with more than 100000 plates are presented within 4 min analysis time.     

Capillary Electrochromatography with Monolithic Poly(styrene‐co‐divinylbenzene‐co‐methacrylic acid) as the Stationary Phase

A new kind of monolithic capillary electrochromatography column with poly(styrene‐co‐divinylbenzene‐co‐methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically. The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed‐phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.     

Separation of Hydroxybenzoic Acid Isomers by Capillary Zone Electrophoresis

Abstract

Capillary zone electrophoresis is a highly efficient analytical technique that has been shown to be particularly useful for the analysis of isomers. Using a cathodic injection and anodic detection scheme, ortho-, meta- and para-hydroxybenzoic acids were separated in a fused-silica capillary column with a phosphate buffer at pH 10.3 (25.0 mmol/1 phosphate + 0.20 mmol/1 cetyltrimethylammonium bromide (CTAB) + 10% (v/v) 1-propanol with an applied voltage of 10 KV followed by direct UV detection. The use of CTAB as electroosmotic flow modifier allows the rapid separation of the three isomers by reversing the direction of electro-osmotic flow. The influence of pH, CTAB concentration and organic solvents on the migration behaviour of the solutes were also studied.