6-O-(Hydroxypropyltrimethylammonia)-β-cyclodextrin with Low Degree of Substitution: Convenient Preparation and its Application as a Chiral Selector in Capillary Electrophoresis

A cationic cyclodextrin derivative 6-O-（hydroxypropyltrimethylammonia）-β-cyclodextrin （GTA-β-CD） with low degree of substitution was prepared through a convenient method in solid phase. The product could be used as a valuable chiral selector in the capillary electrophoresis （CE） separation of some acidic drug enantiomers such as naproxen, ofloxacin, ibuprofen and warfarin.

Separation of Purine and Its Derivatives by Capillary Zone Electrophoresis

The separation of a group of 17 purine and its derivatives by capillary zone electrophoresis is presented. A systematic approach was used to study the effect of pH, buffer type, organic modifiers, applied potential, sodium dodecyl sulfate (SDS) and cyclodextrins on the separation of these purine derivatives. An ideal condition was found for their separation, which was 30 mmol/L sodium borate buffer (pH 9–9.5), 10%(V/V) methanol buffer modifier and 20 kV. Under this condition, the 17 purine derivatives were baseline separated and the linear correlation coefficient for adenine, uric acid and 2-thioxanthine was 0. 99 over two orders of magnitude. The variation of peak areas was less than 4. 6%(n=5) and that of migration times was in the range of 0%–3%, while the samples were injected hydrodynamically at a height of 15 cm and an injection time of 8–10 s. In addition, alcohol, 1-propanol, 1-butanol and acetonitrile were also effective additives in the separation. However, SDS and various β-cyclodextrin (β-CDs) were found to do no good to their separation.

Preparation of β-Cyclodextrin Modified FusedSilica Capillary and Its Application inCapillary Electrophoresis Enantiom eric Separation

A simple type of chiral selector immobilized capillaries was prepared and applied to the separation of some enantiomers by capillary electrophoresis(CE) without chiral selective reagents in a buffer solution. β Cyclodextrin (CD) was bonded to the inner wall of fused silica capillary with the aid of 3 (2 cyclooxypropoxyl) propyl trimethoxy silane or 3 aminopropyltriethoxyl silane as bridge. The synthesis conditions such as reaction temperature, reaction ratios, solvents were optimized. The stability and reproducibility of the CD modified capillaries were studied under different operation conditions. It is satisfactory to apply the capillary to the chiral separation of d,l adrenaline and the atracurium besilate diastereoisomers under the optimized conditions.

Method Development of Enantiomer Separations by Affinity Capillary Electrophoresis,Cyclodextrin Electrokinetic Chromatography and Capillary Electrophoresis-Mass Spectrometry

Capillary electrophoresis (CE) has become a powerful tool for enantiomer separations during the last decade. Since 1993, the author has investigated enantiomer separations by affinity capillary electrophoresis (affinity CE) with some proteins and by cyclodextrin electrokinetic chromatography (CDEKC) with some charged cyclodextrins (CDs). Many successful enantiomer separations are demonstrated from our study in this review article. In the enantiomer separations by affinity CE, the deterioration of detection sensitivity was observed under high concentration of the protein in running solutions. The partial filling technique was practically useful to solve the serious problem. It allowed operation at high protein concentrations, such as 500 μmol/L, without the detection problem. Charged CDs had several advantages for the enantiomer separations over neutral ones. Strong electrostatic interactions between a charged CD and oppositely charged analytes should be effective for the formation of the complex. A large difference in electrophoretic mobility between the free analyte and the inclusion complex should also enhance the enantiomeric resolution. In CE mass spectrometry (CE MS), the partial filling technique was applied to avoid the introduction of nonvolatile chiral selectors into the CE MS interface. By replacing the nonvolatile electrolytes in the running buffer by volatile ones, the separation conditions employed in CE with the UV detection method could be transferred to CE MS.

Synthesis and Characterisation of Water-Soluble Carboxymethyl-Cyclodextrin Polymer as Capillary Electrophoresis Chiral Selector

The water-soluble carboxymethyl-cyclodextrin polymer (CM-CD polymer) was synthesized and used as capillary electrophoresis chiral selector. Verrapamil and thiopentorusodium were well separated using CM-CD polymer as chiral selector.

The Enantiomer Separations of Allethrone and Propargyllone Using Two Long Chain Acylated b-Cyclodextrin Derivatives as CGC Capillary Stationary Phases

Using two b-cyclodextrin derivatives (CDs) with long chain of acyl groups as chiral stationary phases (CSPs) of capillary gas chromatography (CGC), the enantiomers of racemic allethrone and propargyllone were well resolved after derived with acetyl chloride. The enantiomer excess values (e.e.%) of 1S-allethrone and 1S-propargyllone were also determined successfully using these CDs.

Chiral Separation of Esmolol and Terazosin by Cyclodextrinmodified Capillary Zone Electrophoresis

Cyclodextrin-modified CZE was applied to the chiral separation of two basic drugs, i.e., esmolol and terazosin. Selector screening and concentration optimization experiments were performed. Resolution 3.1 for esmolol, 1.2 for terazosin were achieved when using 60 mmol/L gamma-CD and 60 mmoL/L DM-P-CD, respectively, in 50 mmol/L pH 2.5 sodium phosphate buffer.

Synthesis of Amino Acid Derived β-Cyclodextrins Used in Chiral Separation by Capillary Electrophoresis

Six new kinds of amino acid derived β-cyclodextrins were synthesized to improve their water solubility and chiral separation properties. They are heptakis{2,6-di-O-[3-L-(1-isopropyl carboxyl methyl amino)-2-(hydroxy) propyl]}-β-cyclodextrin (i.e. L-Val-β-CD), heptakis{2,6-di-O-[3-L-(1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Phe-β-CD), heptakis{2,6-di-O-[3-(D, L-1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. D,L-Phe-β-CD), heptakis{2,6-di-O-[3-(L-1-hydroxymethyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Ser-β-CD), heptakis{2,6-di-O-[3-(L-1-carboxylmethyl carboxyl methyl amino)- 2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Asp-β-CD), heptakis{2,6-di-O-[3-(L-2-carboxyl tetramethylene amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Pro-β-CD). Their chemical structures were certified using FTIR and ()~1H NMR. Except for L-Phe-β-CD and D,L-Phe-β-CD, that are in soluble in water, the other amino acid derived β-CDs all have good water solubility. D,L-tyrosine and promethazine were baselinely separated by L-Val-β-CD in capillary electrophoresis.

Separation of chiral drugs with sulfobutylether-β-cyclodextrin bycapillary zone electrophoresis

Sulfobutylether－β－cyclodextrin（SBE－β－CD）was used as a chiral selector tor separatingten chlral drugs with resolution 1．2 by capillary zone electrophoresls（CZE）， The backgroundelectrolylc solution comprised of 120 mmol／L Britton－Robinson buffer（BRB） containing1 ～10mmol／L SBE－β－CD with the pH value adjusted from 5．0－6．8． Five of the drugs were better resolvedthan those previously reported with neutral CDs．

Determination Enantiomer Excess(e.e.%)of Chiral Sharpless Epoxides with β-Cyclodextrin Derivatives as Chiral Stationary Phases of Capillary Gas Chromatography

Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di- O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzyl -6-O- octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography （CGC）, the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values （e.e.%） of some chiral Sharpless epoxides were also determined successfully using these CDs.

Determination of Enantiomeric Purity of ν-Pyrrolidinyl Phenylpropanol by Capillary Electrophoresis Using β-Cyclodextrin Polymer as Chiral Selector

Enantiomer of n-pyrrolidinyl phenylpropanol was studied by capillary electrophoresis using b-cyclodextrin polymer as chiral selector. We determined the enantiomeric excess value of n-pyrrolidinyl phenylpropanol with RSD 0.48%.

Chiral Separation of Chlorpheniramine by Capillary Electrophoresis *L

Aim To study the chiral separation of chlorpheniramine(Chp) by using a mixture of β CD and glutamate β CD as the chiral additive in CE. Methods Mixture of β cyclodextrin and glutamate β cyclodextrin was used as a chiral selector to the separation of chlorpheniramine. The effects of the concentrations of β cyclodextrin and glutamate β cyclodextrin, the voltage and the pH of buffers on the separation of chlorpheniramine were studied. Results The chiral recognization of the mixed chiral selector was better than that of a single selector. At pH below 4, the pH of buffers did not affect the separation and the separation of chlorpheniramine had good reproducibility. Conclusion Using a mixture of β CD and Glu β CD as chiral selector is useful for the enantioseparation of Chp in CE.

A NOVEL DERIVATIVE OF β-CYCLODEXTRIN AS CHIRAL SIATIONARY PHASE IN CAPILLARY GAS CHROMATOGRAPHY

A novel β-cyclodextrin derivative, 2, 6-di-O-butyl-3-O-acetyl-β-cyclodex- trin, was prepared and used as chiral stationary phase for capillary gas chromato- graphic resolution of enantiomers, lhe glass capillary columns with the derivative having low melting point and high thermal stability could produce more than 3000 plates per column meter and have proven to be good chlral columns to separate the enantiomers of some amino acids, derivatives of epoxy ethane and alkyl halide, etc.

Alkylated and silylated β-cyclodextrin for gas chromatographic chiral stationary phases

Three new chiral stationary phases, 2,6 di O heptyl 3 O trimethylsilyl β cyclodextrin(DHTBCD), 2,6 di O pentyl 3 O trimethylsilyl β cyclodextrin (DPTBCD) and 2,6 di O butyl 3 O trimethylsilyl β cyclodextrin (DBTBCD), were synthesized. Chromatographic properties such as column efficiency, thermal stability and column life span, were studied. The separations of enantiomers, such as ketone, esters, alcohols and olefines, were investigated on the alkylated and silylated β cyclodextrin stationary phases. The influence of diluent on chiral separation was studied. The experimental results indicate that the stationary phases show good chromatographic properties in separating enantiomers. It is observed that inclusion complexation and hydrogen bonding interaction hardly play a role in separating enantiomers.

Separation of chiral drugs with β-CD phosphate by capillary electrophoresis

β-Cyclodextrin phosphate (β-CD-phosphate) was used as a selector for separating chiral drugs by capillary electrophoresis (CE). A solution comprising of 120 mmol/L Britton Robinson buffer (BRB) containing 10 mmol/L 0-CD phosphate with the pH adjusted to 7.0 was used as the background electrolyte (BGE), and a small amount of analyte was injected (600v/1s). Triethylamine, diethylamine, triethanolamine, diethanolamine, Tris added as modifier were compared. Isoprenaline, methoxamine, oxprenolol, practolol were successfully resolved.

Carboxymethyl-β-Cyclodextrin for Chiral Separation of Basic Drugs by Capillary Elcctrophoresis

Four basic drugs were separated by capillary electrophoresis (CE) usingcarboxymethyl-β-yclodextrin (CM-0-CD) as chiral selector. The effects of CM-β-CDconmptration, applied voltage. operation temperature were investigated. Under the selectedconditions. norephedrine. ofloxacin. terbutaline and chlorpheniramine were enantiomerallybaieline-separated using H3PO4-triethanolamine buffer at PH 3 containing 10, 5.5, 2. 2mmol/LCM-β-CD respectively.

Separation Properties of a New Polysiloxane-Anchored β-Cyclodextrin Derivative as Gas Chromatography Stationary Phase

A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It exhibited separation abilities to disubstituted benzene isomers and some chiral solutes. It was also found that the polarity of CD derivatives can be lowered both by chemically bonding it to polysiloxane and by diluting it in polysiloxane. The separation abilities of the polysiloxane anchored CDs (SP CD) are higher than that of the unbonded CDs (S CD) and the diluted S CD at lower column temperature. Hydrosilylation reaction is one of the best methods to lower the operating temperature of CDs.

超声萃取-亲和毛细管电泳-激光诱导荧光法同时测定纺织品和食品塑料包装中16种多环芳烃的含量

通过优化背景电解液酸度及背景电解液中硼砂、羧甲基-β-环糊精(CM-β-CD)、二甲基-β-环糊精(DM-β-CD)的浓度,利用多环芳烃(PAHs)与CM-β-CD以及PAHs与DM-β-CD亲和力的差异,提出了提示方法。参考GB/T 28189-2011进行样品前处理,将样品剪成0.5 cm×0.2 cm的细条,分取1 g,加入50 mL环己烷,密封后于50℃超声提取1 h。冷却至室温,过滤,滤液用附激光诱导荧光检测器的高效毛细管电泳仪分析,背景电解液为含30 mmol·L^(-1)CM-β-CD、20 mmol·L^(-1)DM-β-CD和40 mmol·L^(-1)硼砂的混合溶液(pH 5.0),荧光检测波长为325 nm。结果显示:16种PAHs的质量浓度在0.01~0.5 mg·L^(-1)内与峰面积呈线性关系,检出限为0.002~0.040 mg·L^(-1);按照标准加入法进行回收试验,结果为91.4%~104%,测定值的相对标准偏差(n=5)为0.40%~6.3%。方法用于3种纺织品以及5种食品塑料包装的分析,8种样品均不同程度地检出了PAHs。

毛细管区带电泳法测定儿童药品中6种着色剂

建立羟丙基-β-环糊精修饰的毛细管区带电泳法测定儿童药品中6种着色剂的含量。选择未涂层石英毛细管柱(68.5 cm×75μm),分离缓冲液为10 mmol/L硼酸盐缓冲液(含20 mmol/L的聚乙二醇4000和20 mmol/L的羟丙基-β-环糊精,pH 8.0),检测波长为210 nm,电泳电压为20 kV,进样压力为5 kPa,进样时间为5 s。酸性橙7、诱惑红、酸性蓝74、苋菜红、柠檬黄、丽春红4R分离效果良好,其质量浓度在0.3~3.0 mg/L范围内与对应的电泳峰面积线性关系良好,线性相关系数均不小于0.9990,检出限为0.001~0.004 mg/L,定量限为0.003~0.013 mg/L,样品加标平均回收率为94.0%~99.9%,测定结果的相对标准偏差为0.7%~3.2%(n=6)。该方法操作简单、分析速度快、成本低、有实际应用价值,适用于儿童药品多种着色剂的同时分离和检测。

用于检测羧酸的基于高效毛细管电泳的微流控芯片

设计了一种可以进行高效毛细管电泳分析的微流控芯片,微流控芯片具有一个十字架结构的沟道,沟道横截面的尺寸为100μm×50μm。利用5-氨基甲基荧光素作为荧光探针,使用乙腈溶液与磷酸盐缓冲液作为流动相进行高效液相色谱分析,等量洗脱确认了丙酸到十八烷酸(C3~C18)的衍生物色谱图,并通过高效毛细管电泳分析将丙酸(C3)、己酸(C6)、癸酸(C10)进行分离,成功分离C3和C10,C3和C10的分离度为2.2,分离效果良好。此外,针对高效毛细管电泳分析出现的不稳定电渗现象而导致实验数据不稳定的情况,加入阳离子聚合物六甲溴铵和阴离子聚合物硫酸葡聚糖钠盐形成连续的多个离子聚合物涂层,使得微流控芯片对羧酸检测的稳定性大大提高。