Capillary electrophoresis of seed 2S albumins from Lupinus species

Two modes of capillary electrophoresis (CE)--free-solution capillary zone electrophoresis (CZE) and sodium dodecyl sulfate capillary electrophoresis (SDS-CE) using a non-gel sieving matrix--have been developed for comparative analysis of low-molecular-mass 2S albumin isoforms from lupins. The albumin fraction and 2S albumins were separated in uncoated fused-silica capillary by CZE with 0.02 M phosphate buffer, pH 7.3, containing the sodium salt of phytic acid. The use of phytic acid (0.025 M) as buffer modifier and ion-pairing agent improved migration reproducibility, peak shape and separation efficiency. The reduced 2S albumins were separated by SDS-CE using a high concentration (0.3-0.5 M) mixture of tris(hydroxymethyl)aminomethane and borate buffers in uncoated fused-silica capillary. Of the various polymers used as non-gel sieving matrix, SDS-CE with a 10% dextran solution was found to be suitable for separation of 2S albumin polypeptides with molecular masses of 4,000-7,000 and 8,000-11,000. The addition of glycerol or ethylene glycol to the SDS separating buffer improved the resolution of polypeptides. The examined Lupinus species showed species-specific CZE and SDS-CE migration profiles of the 2S albumins.     

Para-hydroxybenzoic acid as an indirect detection buffer in capillary zone electrophoresis

Summary Para-hydroxybenzoic acid (p-HBA) has been used as indirect UV detection buffer in capillary zone electrophoresis (CZE). Being an UV-absorbing dibasic acid, p-HBA provides both the necessary buffering for pH control over a wide range and UV absorbance for indirect detection. With sodium dodecyl sulfate (SDS) as a probe, a CZE method using p-HBA solution as running buffer was developed to analyze anions, especially ones with low electrophoretic mobilities. The method was used to separate homologous series of sulfonates, SDS in a formulation sample, and SDS in a standard.     

高效毛细管电泳,激光干涉检测快速分离二糖研究

首次报道一种高效毛细管电泳、激光干涉折射检测快速分离二糖的新方法。详细研究了四硼酸钠溶液中，ｐＨ值、四硼酸钠浓度及有机添加剂对二糖－硼酸络离子迁移行为的影响，发现在ｐＨ为９．７的０．１ｍｏｌ／Ｌ四硼酸钠溶液中，１０ｍｉｎ内４种二糖得到基线分离。采用自制激光干涉型折射指数检测器，不需对二糖衍生化处理，可直接进行在柱检测。     

毛细管区带电泳法测定卷烟中的生物碱

在磷酸缓冲体系中采用毛细管区带电泳法测定卷烟中的生物碱时,检测灵敏度低,分离度差。考察了卷烟中生物碱的 提取条件,分离缓冲溶液的类型、pH值和浓度,卷烟中生物碱测定方法的线性范围、检出限、重现性和回收率。结果发 现,当采用410 mmol/L的酒石酸溶液（pH 2.8）为缓冲体系时,卷烟中生物碱的检测灵敏度和分离度均有明显改善,烟碱 的线性范围为0.06~0.80 mg/L（其他生物碱为0.006~0.10 mg/L）,检出限为0.002~0.01 mg/L,相对标准偏差为2.2%~10%,回收率为87.6%~102%。     

Applications of a sulfonated-polymer wall-modified open-tubular fused-silica capillary in capillary zone electrophoretic separations

A fused-silica capillary that is wall-modified via chemically bonding a sulfonated polymer to the capillary wall has a uniform negative charge density on its surface and produces an electroosmotic flow (EOF) greater than 4 x 10(-4) cm2 V(-1) s(-1) The EOF is nearly independent of buffer pH over the pH range of 2 to 10 and is lower than the EOF obtained for the bare fused-silica capillary at the more basic pH but is higher at the more acidic buffer pH. Optimization of buffer pH can be based on analyte pKa values to improve the overall quality of the capillary zone electrophoresis (CZE) separation of complex mixtures of weak acid and base analytes. Because of the high EOF in an acidic buffer, the capillary is useful for the separation of weak organic bases which are in their cation forms in the acidic buffer. EOF for the sulfonic acid bonded phase capillary can be adjusted via buffer additives such as organic solvent, tetraalkylammonium salts, multivalent cations and alkylsulfonic acids. The advantages of utilizing buffer pH and the EOF buffer modifiers to enhance migration time, selectivity, and resolution in CZE separations with this capillary are illustrated using a series of test analyte mixtures of inorganic anions, carboxylic acids, alkylsulfonic acids, benzenesulfonic acids, sulfas, pyridines, anilines or small-chain peptides.     

毛细管区带电泳法测定血浆中的苯妥英钠

 建立了以毛细管区带电泳测定血浆中苯妥英钠含量的方法。此法具有良好的重现性和线性关系 ,日内、日间的平均相对标准偏差分别为 3.1%和 4 .7% ,平均回收率大于 95 % ,标准曲线的相关系数为 0 9985 ,是一种简便、快速、准确、灵敏的测定方法 。     

毛细管区带电泳法拆分匹伐他汀钙对映体

建立了匹伐他汀钙对映体的毛细管区带电泳(CZE)拆分方法。分别考察了电泳电压,缓冲溶液种类、浓度及pH值,环糊精种类及浓度,添加剂种类及浓度等参数对实验结果的影响,从而确定了匹伐他汀钙对映体的最佳拆分条件: 电泳电压为18 kV;运行缓冲溶液为80 mmol/L的Tris-HCl缓冲体系,pH值为3.20,其中含有50 mmol/L HP-β-CD(羟丙基-β-环糊精)和5 mmol/L SDS(十二烷基磺酸钠);采用重力进样,进样高度17 cm,进样时间为2 s。在优化的实验条件下,匹伐他汀钙对映体得到了较好的分离,分离度可达2.17。实验结果表明该方法可用于匹伐他汀钙对映体的分离,具有快速、便捷、准确性好等优点。     

开管毛细管电色谱分析3种解热镇痛药物

针对生物体液样品开展药物的绿色高效毛细管电泳分离分析具有重要的研究意义。该研究以3种解热镇痛药（4-氨基安替比林、氨基比林及非那西汀）为研究对象,以嵌段聚合物为涂层,建立了药物的开管毛细管电色谱（OT-CEC）分析新策略。首先,采用活性/可控自由基可逆加成-断裂链转移聚合方法,合成制备得到了两亲性嵌段聚合物-聚（苯乙烯-甲基丙烯酸缩水甘油酯）（P（St-GMA））,并将其涂覆到毛细管内壁;其次,通过考察影响OT-CEC分离效率的关键因素,包括嵌段聚合物的聚合时间、涂覆毛细管嵌段聚合物的浓度、电泳运行缓冲液的种类和pH值、有机溶剂添加剂等,优化了3种解热镇痛药物的OT-CEC分离条件;最终发现,不需添加任何有机溶剂及表面活性剂,仅采用50.0 mmol/L乙酸钠-乙酸（pH 5.7）作为OT-CEC的缓冲溶液,就能实现3种解热镇痛药物的基线分离。在8.0~2.5×10³ μmol/L范围内,分析物峰面积与其对应的浓度呈现良好的线性关系,相关系数（R²）均大于0.995,检出限为1.0~2.5 μmol/L。结果表明：P（St-GMA）在溶液中自组装所形成的类表面活性剂胶团结构增强了两亲性嵌段聚合物与解热镇痛药物之间的相互作用,显著提升了解热镇痛药物的OT-CEC分离效率。该工作不仅为制备新型聚合物及调控嵌段聚合物的自组装行为提供了研究思路,也展示了两亲性嵌段聚合物在药物的绿色OT-CEC分析中的实际应用潜力。     

Evaluation of micellar liquid chromatography and capillary zone electrophoresis for dope control in sport

Micellar liquid chromatography (MLC) and capillary zone electrophoresis (CZE) have been evaluated for the analysis of twelve banned drugs in sport including diuretics and -blockers. In MLC, a sodium dodecylsulphate aqueous solution has been used as mobile phase using an octadecylsilica column. In CZE, a pH 8 buffer solution and a silica capillary have been employed. Parameters of retention and efficiency have been compared. Limits of detection with UV detection at 254 nm and relative standard deviations for atenolol, furosemide, nadolol, spironolactone and triamterene were established and compared in both techniques. Examples of direct urine injection into the separation systems are presented. Drugs overlapping in MLC are well resolved in CZE, while the opposite is true for a limited number of drugs. Some interferences from urine may arise in CZE. The selectivity of analysis would be greatly enhanced by using both techniques, which require only filtration as pre-treatment.     

Analysis of selected mycotoxins by capillary electrophoresis

Summary The separation of the mycotoxins ochratoxin A, ochratoxin B, zearalenone and moniliformin by standard capillary zone electrophoresis (CZE) and cyclodextrins modified CE is described. In addition, reversed electroosmotic flow (EOF) conditions via quarternary ammonium running buffer additives have been briefly examined. Parameters influencing selectivity and mobility as well as spectroscopic properties of the analytes have also been investigated. Separations performed at pH values from 5 to 11 show a marked pH dependency of the mobilities accompanied by pronounced shifts of the UV/VIS and/or fluorescence spectra of the compounds. In general, the on-line recording of spectra by diodearray detection (DAD), proved to be highly versatile for peak tracking simultaneously with the structure elucidation and thus for the optimization of sample introduction, peak resolution and detection conditions.     

高效液相色谱法和毛细管电泳法测定甘草制品中甘草酸的含量

分别用高效液相色谱法（ＨＰＬＣ）、毛细管区带电泳法（ＣＺＥ）、胶束电动毛细管色谱法（ＭＥＣＣ）测定了甘草制品中甘草酸的含量。对ＨＰＬＣ,ＣＺＥ,ＭＥＣＣ的分析条件作了一些选择实验,结果表明ＭＥＣＣ法与ＨＰＬＣ法分析数据接近、比较准确,而且前者比ＨＰＬＣ法分离效率高、溶剂用量少,是一种很有发展潜力的分析方法。     

Wall deactivation with fluorosurfactants for capillary electrophoretic analysis of biomolecules

This paper describes the use of fluorosurfactants as buffer additives for capillary electrophoretic separation of proteins and peptides. Due to fluorosurfactant bilayer formation at the capillary inner wall, the surface charge can be adjusted and even reversed. If the running buffer pH is kept at a level where the proteins have the same sign of charge as the wall, electrostatic repulsion will be obtained. The protein wall adsorption can therefore be reduced and the separation performance can be noticeably increased. The separation performance can also be further improved by including mixtures of different types of fluorosurfactants in the running buffer. The buffer system can accordingly be adapted for a certain separation problem. Mechanisms for the use of fluorosurfactants for wall deactivation in capillary electrophoretic protein separations is discussed in the present work and some examples of applications are also presented.     

碱性蛋白质毛细管电泳分离研究

碱性蛋白质毛细管电泳分离研究任吉存，邓延倬，程介克（武汉大学化学系分析测试科学系，武汉，４３００７２）关键词毛细管电泳，碱性蛋白质，吸附，精氨酸，赖氨酸蛋白质的吸附作用严重影响了毛细管电泳分离蛋白质的重现性［１］．为此，人们寻找各种途径来克服蛋白质的...     

Cross-linked poly(vinyl alcohol) as permanent hydrophilic column coating for capillary electrophoresis.

A fast method for the generation of permanent hydrophilic capillary coatings for capillary electrophoresis (CE) is presented. Such interior coating is effected by treating the surface to be coated with a solution of glutaraldehyde as cross-linking agent followed by a solution of poly(vinyl alcohol) (PVA), which results in an immobilization of the polymer on the capillary surface. Applied for capillary zone electrophoresis (CZE) such capillaries coated with cross-linked PVA exhibit excellent separation performance of adsorptive analytes like basic proteins due to the reduction of analyte-wall interactions. The long-term stability of cross-linked PVA coatings could be proved in very long series of CZE separations. More than 1000 repetitive CE separations of basic proteins were performed with stable absolute migration times relative standard deviation (RSD > 1.2%) and without loss of separation efficiency. Cross-linked PVA coatings exhibit a suppressed electroosmotic flow and excellent stability over a wide pH range.     

Separation of N2-ethyl-2'-deoxyguanosine-5'-monophosphate and four native deoxyribonucleoside monophosphates using capillary zone electrophoresis with polyethylene glycol as buffer additive

We investigated the separation of five deoxyribonucleoside monophosphates: 2'-deoxyguanosine-5'-monophosphate (dGMP), 2'-deoxyadenosine-5'-monophosphate (dAMP), 2'-deoxycytosine-5'-monophosphate (dCMP), 2'-deoxythymidine-5'-monophosphate (dTMP) and a dGMP adduct possessing N2-ethyl-guanine, which has been noted in relation to mutagenesis of alcohol, using capillary zone electrophoresis (CZE). The concentration of polyethylene glycol (PEG) as a modifier and the pH of the running solutions can efficiently control the observed separation. Interaction of PEG with analytes was quantitatively evaluated. PEG worked effectively as a hydrophobic selector in these separations. The values of pKa of the acidic-NH-groups in the base moieties of dGMP, dTMP, and the dGMP adduct are close to that of boric acid used as buffer of the running solutions. The control of their charge was facilitated, enabling improved separations. A more sufficient and fast separation was achieved by both optimization of pH of the running solutions and PEG concentration compared with that obtained by pH control alone. On-line concentration using a stacking method followed by the PEG-assisted CZE was briefly studied.     

Separation of naturally occurring triterpenoidal saponins by capillary zone electrophoresis.

A high-performance capillary electrophoresis (HPCE) was successfully applied to the separation and quantitation of naturally occurring oleanene triterpenoidal saponins. The HPCE adapted to the separation of two pairs of disteriomeric saponins (1-2) or (3-4), obtained from Trifolium alexandrinum seeds, was based on capillary zone electrophoresis (CZE) in borate buffer with UV detection at 195 nm. An usual technique for isolation and group separation of saponins was developed as an appropriate purification step prior to determination of individual saponins by CZE. The separation parameters such as borate concentration, pH and applied voltage were varied in order to find the best compromise that complied with demands for high separation, short duration and sufficiently high detector response. The optimum running conditions were found to be 60 mM borate buffer, pH 10 and 12 kV. Under the alkaline borate electrolyte, no resolution was achieved for the saponins (1 and 3) or (2 and 4) in a single mixture, except when 20 mM beta-cyclodextrin was added to the running electrolyte. With the combined techniques of group separation, purification and CZE, a rapid and efficient method for the determination of naturally occurring diasteriomeric saponins is now available.     

Separation and determination of enkephalin-related peptides using capillary electrophoresis

CZE with UV-absorption detection has been used for the separation and determination of enkephalin-related peptides. The experimental conditions, such as pH and concentration of running buffer, applied voltage, injection method, and time, were investigated in detail. Excellent separation efficiency could be obtained for ten enkephalin-related peptides with a 50 microm (ID) x 58 cm capillary using sodium dihydrogen phosphate as the running buffer (pH 3.11) when 20 kV of applied voltage was used. The concentration detection limits were found to be in the range of 0.31-1.94 microg/mL (defined as S/N = 3). The proposed method has been applied to analyze the spiked cerebrospinal fluid (CSF) sample, and the results showed that CZE is a powerful technique for separation and detection of the above biological peptides.     

Determination of preservatives by integrative coupling method of headspace liquid-phase microextraction and capillary zone electrophoresis

An integrative coupling method of headspace liquid-phase microextraction (HS-LPME) and capillary zone electrophoresis (CZE) was proposed in this paper. In the method, a separation capillary was used to create a microextraction droplet of the running buffer solution of CZE, hold the droplet at the capillary inlet, extract analytes of sample solutions in the headspace of a sample vial, inject concentrated analytes into the capillary and separate the analytes by CZE. The proposed method was applied to determine the preservatives of benzoic acid and sorbic acid in soy sauce and soft drink samples, in which the running buffer solution of 50 mmol/L tetraborate (pH 9.2) was directly used to form the acceptor droplet at the capillary inlet by pressure, and the preservatives in a 6-mL sample solution containing 0.25 g/mL NaCl were extracted at 90°C for 30 min in the headspace of a 14-mL sample vial. Then the concentrated preservatives were injected into the capillary at 10 cm height difference for 20 s and separated by CZE. The enrichment factors of benzoic acid and sorbic acid achieved 266 and 404, and the limits of detection (LODs) were 0.03 and 0.01 μg/mL (S/N=3), respectively. The recoveries were in the range of 88.7-105%. The integrative coupling method of HS-LPME and CZE was simple, convenient, reliable and suitable for concentrating volatile and semi-volatile organic acids and eliminating matrix interferences of real samples.     

Separation of phospholipids by capillary zone electrophoresis with indirect ultraviolet detection

A simple method for separation of different anionic and zwitterionic phospholipid classes by capillary zone electrophoresis (CZE), using indirect UV detection with adenosine monophosphate (AMP) as background electrolyte and the UV-absorbing additive, was successfully developed in this study. The separation conditions including apparent pH (pH*) of running buffer, concentration of AMP, organic solvent, applied voltage and capillary temperature were systematically optimized. The application of this method to human blood sample was also briefly examined.     

Influence of ring opening-closure equilibrium of oxanine, a novel damaged nucleobase, on migration behavior in capillary electrophoresis

Oxanine (Oxa) is a novel damaged nucleobase which is generated from guanine by HNO2 or NO. As a fundamental study for detection of Oxa formed in vivo, capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) have been tested by changing the pH of the running buffer. At pH 7, CZE did not separate Oxa from seven other nucleobases, and MEKC separated Oxa but their peaks migrated close together. In both the techniques, an extreme peak broadening occurred for Oxa around pH 9 and a good peak separation was achieved at pH 12. The behavior of the Oxa peak is discussed in relation to the unique multistep acid-base equilibria of Oxa.