Sample records for capillary zone electrophoresis

  1. Capillaries modified by noncovalent anionic polymer adsorption for capillary zone electrophoresis, micellar electrokinetic capillary chromatography and capillary electrophoresis mass spectrometry

    DEFF Research Database (Denmark)

    Bendahl, L; Hansen, S H; Gammelgaard, Bente


    A simple coating procedure for generation of a high and pH-independent electroosmotic flow in capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) is described. The bilayer coating was formed by noncovalent adsorption of the ionic polymers Polybrene...

  2. The study of polyoxometalates formation using capillary zone electrophoresis. (United States)

    Zdanov, Artem A; Shuvaeva, Olga V


    The formation process of polyoxometalates [PMo12 O40 ](3-) and [PMo12 - x Vx O40 ](-3-x) has been studied in aqueous solutions of 0.1 M malonate buffer at pH 2.8-3.0 using CZE. Two different approaches, pre-capillary and in-capillary, were examined and compared. In precapillary mode, the reaction mixture of the reactants and reaction products was injected into the capillary followed by the separation procedure. In in-capillary mode, the sequential input of the reagents and running electrolyte into the capillary and the species separation occurs simultaneously. The optimal parameters of in-capillary separation were established as functions of applied voltage and the length of the intermediate buffer zone between the reagents in the capillary. As a result the best-compromise conditions for the separation of the mixtures containing the reactants, intermediates, and reaction products, in order to achieve the best efficiency, symmetry, and peak areas, were achieved at -18 kV and the input parameter of 900 mbar·s. It was also shown that in-capillary mode is more informative than pre-capillary mode for studying the complex compound formation process.

  3. Determination of Size Distribution of Nano-particles by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Yan XUE; Hai Ying YANG; Yong Tan YANG


    A new method was developed for the determination of the size distribution of nano-particles by capillary zone electrophoresis (CZE). Scattering effect of nanoparticles was studied. This method for the determination of size distribution was statistical.

  4. Quantification of Carbohydrates in Grape Tissues Using Capillary Zone Electrophoresis. (United States)

    Zhao, Lu; Chanon, Ann M; Chattopadhyay, Nabanita; Dami, Imed E; Blakeslee, Joshua J


    Soluble sugars play an important role in freezing tolerance in both herbaceous and woody plants, functioning in both the reduction of freezing-induced dehydration and the cryoprotection of cellular constituents. The quantification of soluble sugars in plant tissues is, therefore, essential in understanding freezing tolerance. While a number of analytical techniques and methods have been used to quantify sugars, most of these are expensive and time-consuming due to complex sample preparation procedures which require the derivatization of the carbohydrates being analyzed. Analysis of soluble sugars using capillary zone electrophoresis (CZE) under alkaline conditions with direct UV detection has previously been used to quantify simple sugars in fruit juices. However, it was unclear whether CZE-based methods could be successfully used to quantify the broader range of sugars present in complex plant extracts. Here, we present the development of an optimized CZE method capable of separating and quantifying mono-, di-, and tri-saccharides isolated from plant tissues. This optimized CZE method employs a column electrolyte buffer containing 130 mM NaOH, pH 13.0, creating a current of 185 μA when a separation voltage of 10 kV is employed. The optimized CZE method provides limits-of-detection (an average of 1.5 ng/μL) for individual carbohydrates comparable or superior to those obtained using gas chromatography-mass spectrometry, and allows resolution of non-structural sugars and cell wall components (structural sugars). The optimized CZE method was successfully used to quantify sugars from grape leaves and buds, and is a robust tool for the quantification of plant sugars found in vegetative and woody tissues. The increased analytical efficiency of this CZE method makes it ideal for use in high-throughput metabolomics studies designed to quantify plant sugars.

  5. Determination of Amino Acids in Single Human Lymphocytes after On-capillary Derivatization by Capillary Zone Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)


    Amino acids in individual human lymphocytes were determined by capillary zone electrophoresis with electrochemical detection after on-capillary derivatization. In order to inject cells easily, a cell injector was designed. Four amino acids (serine, alanine, taurine, and glycine) in single human lymphocytes have been identified. Quantitation has been accomplished through the use of calibration curves.

  6. Chiral Separation by Capillary Zone Electrophoresis Used Cyclodextrins and Their Derivatives as Chiral Selector

    Institute of Scientific and Technical Information of China (English)


    @@ Capillary zone electrophoresis (CZE) is a very pronising analytical technique for the optical isomer resolution of the compounds studied. The drawbacks of the techniques such as HPLC [1] were sophisticated stationary phases and/or the relatively high quantity of the chiral agent in the mobile phase, which do not exist in CZE. The capillary electrophoresis (CE) method can offer advantages on lower consumption of analyte and background electrolyte (BGE), shorter analysis time, and higher efficiencies [2-3

  7. Analysis of roller pen inks by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Pengcheng; WANG Yanji; XU Yuanyuan; YAO Lijuan


    The analysis of roller pen inks has become more and more important in fraudulent document examination because of the extensive use of roller pens in financial documents.Capillary electrophoresis with powerful resolution was applied for the analysis of roller pen inks.The experiment focused on the optimization of the separation of the extract from commercially available roller pen entries.A better separation electropherogram was obtained when a 20 mM borate buffer at pH 8.5 and a fused silica capillary with an inner diameter of 100 μm with a total length of 47 (40 cm to the detector window)were used.Five inks from roller pens of different manufacturers and countries were analyzed,and their electropherograms showed that most patterns are distinctly different from each other.Capillary with inner diameter of 100 μm increased the intensity of determination;therefore,color dyes were identified in the visible range and were able to provide more information for comparing types of roller pen inks.

  8. Evaluation of The Interaction between Netropsin and Double Stranded DNA by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    Capillary zone electrophoresis (CZE) was applied to study the interaction between netropsin and a 14mer double stranded DNA (dsDNA). The binding constant of this interaction calculated from Scatchard plot was (1.07±0.10)×105 (mol/L)-1. The binding stoichiometry was 1:1. The use of polyacrylamide coated capillary showed better effect in the analysis of DNA than noncoated capillary.

  9. Analysis of neuropeptides using capillary zone electrophoresis with multichannel fluorescence detection (United States)

    Sweedler, Jonathan V.; Shear, Jason B.; Fishman, Harvey A.; Zare, Richard N.; Scheller, Richard H.


    Capillary zone electrophoresis is fast becoming one of the most sensitive separation schemes for sampling complex microenvironments. A unique detection scheme is developed in which a charge-coupled device (CCD) detects laser induced fluorescence from an axially illuminated electrophoresis capillary. The fluorescence from an analyte band is measured over a several centimeter section of the capillary, greatly increasing the observation time of the fluorescently tagged band. The sensitivity of the system is in the 1-8 X 10-20 mol range for derivatized amino acids and peptides. Subattomole quantities of bag cell neuropeptides collected from the giant marine mollusk Aplysia californica can be measured.

  10. Assay of Histamine in Single Mast Cells by Capillary Zone Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)


    Capillary zone electrophoresis was employed for the analysis of histamine in single rat peritoneal mast cells using an amperometric detector. In this method, individual mast cells and then 0.02 mol/L NaOH as a lysing solution are injected into the front end of the separation capillary. A cell injector was constructed for easy injection of single cells. Histamine in single mast cells has been identified and quantified.

  11. Zone Broadening and Simulation of Migration Process of Peptides in Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    林炳承; 许旭; 罗国安


    The contributions of injection,detection,molecular diffusion and Joule heating to the zonebroadening in capillary zone electrophoresis (CZE) were evaluated theoretically.Approximate equations havebeen derived to calculate the total zone width in CZE.The theoretically calculated values from model formulaagree well with experimental ones.Based on the formula of the total variance,a mathematical expression tocalculate the column efficiency (the plate height) has been derived.The relationship between the column ef-ficiency and experimental conditions has been discussed.Combined in the method to estimate the migrationtime of peptides in CZE,the migration process of the peptides in the column of CZE has been simulated by the computer.


    Capillary zone electrophoresis (CZE) is a very convenient technique for the determination of ionization constants. The technique is rapid, precise, uses small quantities of solute, and the exact concentration of the compound is not needed. This work represents the first report on...

  13. Characterization of the Interaction between Bovine Serum Albumin and Lomefloxacin by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Ming GUO; Qing Sen YU; Jian Wei YAN; Fei TAN; Guo Zheng MA


    Three capillary zone electrophoresis (CZE) methods of the frontal analysis (FA), vacancy peak (VP) and simplified Hummel-Dreyer (SHD) were applied to investigate interaction between bovine serum albumin (BSA) and lomefloxacin, the experimental condition was established after a large number of tests. Based on the site-binding model, the binding parameters were measured according to the site model by Scatchard.

  14. Chiral Separation by Capillary Zone Electrophoresis Used Cyclodextrins and Their Derivatives as Chiral Selector

    Institute of Scientific and Technical Information of China (English)

    HOU; JingGuo


    Capillary zone electrophoresis (CZE) is a very pronising analytical technique for the optical isomer resolution of the compounds studied. The drawbacks of the techniques such as HPLC [1] were sophisticated stationary phases and/or the relatively high quantity of the chiral agent in the mobile phase, which do not exist in CZE. The capillary electrophoresis (CE) method can offer advantages on lower consumption of analyte and background electrolyte (BGE), shorter analysis time, and higher efficiencies [2-3]  ……

  15. Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection. (United States)

    Dickerson, Jane A; Ramsay, Lauren M; Dada, Oluwatosin O; Cermak, Nathan; Dovichi, Norman J


    CIEF and CZE are coupled with LIF detection to create an ultrasensitive 2-D separation method for proteins. In this method, two capillaries are joined through a buffer-filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first-dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second-dimension separation. A fraction was transferred to the second-dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125.

  16. Determination of Dissociation Constants of Complicated Compounds by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    YANG, Geng-Liang; WANG, De-Xian; SUN, Su-Fang; LIU, Hai-Xing; MA, Jian-Jun


    In this work,the whole theoretical metods forthe determinaion ofpKa1 and pKa2 of complicated complicated compounds are proposed by capillary zone electrophoresis.The pka values areachieved by non-linear regression analysis by takiny into consideration the effect of activity coefficient.This is the first report on determining the dissociation constants of gastrodin,magnolol,honkiol,puercetin,curcumin,diethylstilbestrol,diehylstilbestrol,4acetamidophenol,eugenol and paeonol.

  17. A Theoretical Analysis of the Influence of Electroosmosis on the Effective Ionic Mobility in Capillary Zone Electrophoresis (United States)

    Hijnen, Hens


    A theoretical description of the influence of electroosmosis on the effective mobility of simple ions in capillary zone electrophoresis is presented. The mathematical equations derived from the space-charge model contain the pK[subscript a] value and the density of the weak acid surface groups as parameters characterizing the capillary. It is…

  18. Studies of Active Ingredients in Cough Syrup by Capillary Zone Electrophoresis with Amperometric Detection

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tian-shu; WANG Ai-fang; WU Fang; SHI Guo-yue; FANG Yu-zhi


    The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0.9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.

  19. Chiral separation of benzothiazole derivatives of amino acids using capillary zone electrophoresis. (United States)

    Nováková, Zuzana; Pejchal, Vladimír; Fischer, Jan; Česla, Petr


    A method for the separation of enantiomers of leucine and phenylalanine benzothiazole derivatives as potential antimicrobial agents was developed using capillary zone electrophoresis with a dual cyclodextrin (CD) system. The best resolution of enantiomers was achieved in 100 mmol/L phosphate background electrolyte (pH 3.5) with the dual CD system consisting of 10 mmol/L of β-CD with 10 mmol/L of 2-hydroxypropyl-β-cyclodextrin for leucine derivative and 10 mmol/L of 2-hydroxypropyl-γ-cyclodextrin for phenylalanine derivative, respectively. Under the optimal conditions, the highest enantioresolution of 1.25 was achieved in a noncoated-fused silica capillary at 17°C and 24 kV applied voltage.

  20. Capillary zone electrophoresis analysis and detection of mid-spectrum biological warfare agents

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, C.A.; Townsley, C.


    DRE Suffield has initiated a research program to develop methods and equipment for field detection and laboratory identification of mid-spectrum agents, molecules of biological origin such as proteins, peptides and toxins. In this study, a highly efficient and reproducible capillary zone electrophoresis method was developed to separate and identify a series of nine peptides of defence interest: bradykinin, bradykinin fragment 1-5, substance P,ARG8-vasopressin, luteinizing hormone releasing hormone, bombesin, leucine enkephalin, methionine enkephalin, and oxytocin. Using a 50 micrometer x 47 cm capillary column, 22.5 kV separation voltage and a 100 mM pH 2.5 phosphate buffer, all nine peptide could separated in under 10 minutes. Three strategies, which could be used in a fully automated field detection and identification system, were demonstrated for the identification of unknown peptides: comparison of migration times, comparison of electrophoretic mobilities, and co-injection of multiple reference standards. These experiments demonstrate that a separation based analytical method such as capillary electrophoresis could form the basis of a generic detection system for mid-spectrum protein and peptide toxins.

  1. [Determination of chondroitin sulfate in food supplements by capillary zone electrophoresis]. (United States)

    Arianova, E A; Bogachuk, M N; Perederiaev, O I


    Chondroitin sulfate is widely used as an ingredient in food supplements. A method of capillary zone electrophoresis for qualitative and quantitative analysis of chondroitin sulfate in food supplements has been developed. The system of capillary electrophoresis Agilent 3D CE (USA) with diode array detector (spectral range 190-400 nm, 192 nm was used to quantity), quartz capillary Agilent with effective length 56 cm (USA) (internal diameter 50 microm, temperature 25 degrees C, 30 kV, negative polarity) and 50 mM phosphate buffer (pH 3.5) has been used. Quantity limit of this method was 0.5 g/kg. It was used for determination of content of chondroitin sulfate in 14 food supplements. The chondroitin sulfate was detected in all test samples with deviation from the declared content (25-600 mg per capsule or tablet) at the level of 1 to 9%. The applicability of the elaborated method for assessing of food supplements quality has been shown.

  2. Effective electrophoretic mobilities and charges of anti-VEGF proteins determined by capillary zone electrophoresis. (United States)

    Li, S Kevin; Liddell, Mark R; Wen, He


    Macromolecules such as therapeutic proteins currently serve an important role in the treatment of eye diseases such as wet age-related macular degeneration and diabetic retinopathy. Particularly, bevacizumab and ranibizumab have been shown to be effective in the treatment of these diseases. Iontophoresis can be employed to enhance ocular delivery of these macromolecules, but the lack of information on the properties of these macromolecules has hindered its development. The objectives of the present study were to determine the effective electrophoretic mobilities and charges of bevacizumab, ranibizumab, and model compound polystyrene sulfonate (PSS) using capillary zone electrophoresis. Salicylate, lidocaine, and bovine serum albumin (BSA), which have known electrophoretic mobilities in the literature, were also studied to validate the present technique. The hydrodynamic radii and diffusion coefficients of BSA, bevacizumab, ranibizumab, and PSS were measured by dynamic light scattering. The effective charges were calculated using the Einstein relation between diffusion coefficient and electrophoretic mobility and the Henry equation. The results show that bevacizumab and ranibizumab have low electrophoretic mobilities and are net negatively charged in phosphate buffered saline (PBS) of pH 7.4 and 0.16M ionic strength. PSS has high negative charge but the electrophoretic mobility in PBS is lower than that expected from the polymer structure. The present study demonstrated that capillary electrophoresis could be used to characterize the mobility and charge properties of drug candidates in the development of iontophoretic drug delivery.

  3. Simultaneous determination of phenylethanoid glycosides and aglycones by capillary zone electrophoresis with running buffer modifier. (United States)

    Dong, Shuqing; Gao, Ruibin; Yang, Yan; Guo, Mei; Ni, Jingman; Zhao, Liang


    Although the separation efficiency of capillary electrophoresis (CE) is much higher than that of other chromatographic methods, it is sometimes difficult to adequately separate the complex ingredients in biological samples. This article describes how one effective and simple way to develop the separation efficiency in CE is to add some modifiers to the running buffer. The suitable running buffer modifier β-cyclodextrin (β-CD) was explored to fast and completely separate four phenylethanoid glycosides and aglycones (homovanillyl alcohol, hydroxytyrosol, 3,4-dimethoxycinnamic acid, and caffeic acid) in Lamiophlomis rotata (Lr) and Cistanche by capillary zone electrophoresis with ultraviolet (UV) detection. It was found that when β-CD was used as running buffer modifier, a baseline separation of the four analytes could be accomplished in less than 20 min and the detection limits were as low as 10(-3) mg L(-1). Other factors affecting the CE separation, such as working potential, pH value and ionic strength of running buffer, separation voltage, and sample injection time, were investigated extensively. Under the optimal conditions, a successful practical application on the determination of Lr and Cistanche samples confirmed the validity and practicability of this method.

  4. p-Hydrazinobenzenesulfonic Acid Derivatives of Carbohydrates and Their Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    p-Hydrazinobenzenesulfonic acid is explored as a novel ultraviolet labeling reagent for capillary electrophoresis (CE) of mono- and disaccharides. The labeling reaction takes less than 10 minutes and introduces both of absorption and charge groups into the sugars.

  5. Separation and determination of cefotaxime enantiomers in injections by capillary zone electrophoresis. (United States)

    Wang, Rong; Jia, Zheng-Ping; Fan, Jun-Jie; Ma, Jun; Hua, Xie; Zhang, Qiang; Wang, Juan


    Cefotaxime enantiomers have specific effects on Gram-negative bacteria. For quality control of cefotaxime it was necessary to establish a method for enantioseparation by capillary zone electrophoresis (CZE) using cyclodextrin (CD) as a chiral selector. The effects of various parameters on enantioseparation were studied. A fused silica capillary (40 cm effective length x 75 microm ID) was used. The cefotaxime enantiomers were separated on the baseline under conditions of 0.5 mmol/L CM-beta-CD, 75 mmol/L NaH2PO4 buffer at pH 7.0 using UV detection at 280 nm. Applied voltage and capillary temperature were 20 kV and 25 degrees C, respectively. Under these conditions for enantioseparation, linear calibration curves were obtained in the range 2 approximately 160 microg/mL. The limit of detection for both isomers was less than 0.5 microg/mL. The method was used for analysis of pharmaceutical preparations (dosage forms) of cefotaxime from various factories. A simple and specific CZE method was successfully demonstrated for the separation of cefotaxime enantiomers. The enantioseparation method should be established and this method should be used to control the quality of cefotaxime.

  6. Simultaneous determination of cimetidine, famotidine, nizatidine, and ranitidine in tablets by capillary zone electrophoresis. (United States)

    Wu, S M; Ho, Y H; Wu, H L; Chen, S H; Ko, H S


    A simple capillary zone electrophoresis (CZE) method is described for the simultaneous determination of cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine (RAN). The analysis of these drugs was performed in a 100 mM phosphate buffer, pH 3.5. Several parameters were studied, including wavelength for detection, concentration and pH of phosphate buffer, and separation voltage. The quantitative ranges were 100-1,000 microM for each analyte. The intra- and interday relative standard deviations (n = 5) were all less than 4%. The detection limits were found to be about 10 microM for CIM, 20 microM for RAN, 20 microM for NIZ, and 10 microM for FAM (S/N = 3, injection 1 s) at 214 nm. All recoveries were greater than 92%. Applications of the method to the assay of these drugs in tablets proved to be feasible.

  7. Determination of ibuprofen and flurbiprofen in pharmaceuticals by capillary zone electrophoresis. (United States)

    Hamoudová, Rafifa; Pospísilová, Marie


    Capillary zone electrophoresis with spectrophotometric detection was used for the determination of ibuprofen (IB) and flurbiprofen (FL) in pharmaceuticals. The separation was carried out in a fused silica capillary (60 cm x 100 microm i.d. effective length 45 cm) at 30 kV with UV detection at 232 nm. The optimized background electrolyte was 20mM N-(2-acetamido)-2-aminoethanesulfonic acid (ACES) with 20mM imidazole and 10mM alpha-cyclodextrin of pH 7.3. 2-Naphthoxyacetic acid was used as internal standard. A single analysis took less than 5 min. Rectilinear calibration ranges were 2-500 mg l(-1) for IB and 1-60 mg l(-1) for FL. The relative standard deviations (R.S.D.) values (n=6) were 1.53% for IB and 1.29% for FL (for 200 mg l(-1) IB and 10 mg l(-1) FL). This validated method has been successfully applied for the routine analysis of 10 commercially available pharmaceutical preparations (syrup, tablets, cream and gel).

  8. [Improvement of carbohydrate deficient transferrin measurement by capillary zone electrophoresis using immunosubtraction of immunoglobulins and transferrin]. (United States)

    Baraud, J; Schellenberg, F; Pagès, J-C


    CDT (Carbohydrate Deficient Transferrin) is considered as the most efficient biomarker of alcohol abuse available for routine use. Among the various methods developed for its measurement, capillary zone electrophoresis (CZE) on the multicapillary analyzer Capillarys2 provides high quality results at high throughput. However, the non CDT specific measurement of protein absorbance at 200 nm may bring abnormal profiles in samples from patients with high polyclonal immunoglobulin level or monoclonal component. We evaluated the automated immunosubtraction procedure developed by the manufacturer in 48 samples with abnormal electrophoretic profiles that potentially could interfere with CZE measurement of CDT. Elimination of the serum immunoglobulins raised the number of interpretable profiles from 19 (40%) to 37 (77%). The immunosubtraction procedure failed in samples with a monoclonal component present at a concentration > 60 g/L and in some samples harbouring a partially degraded C3 fraction. Six samples identified as genetic BC transferrin variants were also included in the study and submitted to an automated transferrin subtraction procedure to ascertain whether the additional peak were actually transferrin glycoforms. After treatment, two samples were classified as homozygote C for transferrin due to the persistence of one of the supposed transferrin peak. In conclusion, immunoglobulin and transferrin subtraction allow a better CDT measurement in most samples with interfering monoclonal components and avoid misclassification of suspected transferrin BC or CD variants.

  9. On-Line Multichannel Raman Spectroscopic Detection System For Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    An on-line multichannel Raman spectroscopic detection system for capillary electrophoresis was established by using an Ar+ laser and a cryogenically cooled ICCD. Resonant excitation Raman spectra of methyl red and methyl orange were employed to test the system. The result shows that it could yield on-line electrophoretogram and time series of Raman spectra.

  10. Capillary zone electrophoresis for enumeration of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in yogurt. (United States)

    Lim, Orathai; Suntornsuk, Worapot; Suntornsuk, Leena


    Enumeration of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus is a priority due to their importance in yogurt production. Capillary electrophoresis (CE) of both bacteria could be achieved in 7.2 min with a resolution of 3.2 in the background electrolyte (BGE) containing 4.5mM Tris(hydroxymethyl) amminomethane (TRIS)-4.5 mM boric acid-0.1 mM ethylenediamine tetraacetate (EDTA) (TBE) buffer (pH 8.4) and 0.05% (v/v) polyethylene oxide (PEO), using a capillary of 47.5 cm (effective length) x 100 microm i.d., injection of 50 mbar x 3s followed by -5kV x 120s, a voltage and temperature of 20 kV and 25 degrees C, respectively. Appropriate amounts of PEO in the BGE, sample preparation (i.e. vortex) and introduction were key factors for their separation. A short hydrodynamic injection followed by applying reversed polarity voltage could compress the bacteria into narrow zones, which were detected as separated single peaks. Method linearity (r(2)>0.99), precision (%RSDsyogurt were not statistically different from those of the plate count method (P>0.05). The CE method can be used as an alternative for quantitation of L. delbrueckii subsp. bulgaricus and S. thermophilus in yogurt since it was reliable, simple, cost and labor effective and rapid, allowing the analysis of 3 samples/h (comparing to 2d/sample by plate count method).

  11. A rapid and simultaneous determination of several analgesic antiinflammatory agents by capillary zone electrophoresis. (United States)

    Makino, Kazutaka; Yano, Takahisa; Maiguma, Takayoshi; Teshima, Daisuke; Sendo, Toshiaki; Itoh, Yoshinori; Oishi, Ryozo


    A rapid and simultaneous determination of several analgesic antiinflammatory agents--ibuprofen, acetaminophen, indomethacin, and salicylic acid--in human serum was developed by using capillary zone electrophoresis (CZE) coupled with diode-array ultraviolet detection. After precipitation of serum protein with acetonitrile containing 3-isobutyl-1-methylxanthine as the internal standard, an aliquot of deproteinized samples was applied directly to the CZE system. It enabled us to measure all of these four agents within 6 min, and there were no peaks interfering with the assay of these agents or 3-isobutyl-1-methylxanthine. Both the separation and quantification of these agents in human serum were reproducible after repeated analysis within a day or day-to-day analysis. In addition, there was a good correlation for each drug (r = 0.997-0.999) between the values in serum determined by CZE analysis and those measured either by high-performance liquid chromatography with ultraviolet detection (ibuprofen and indomethacin) or by fluorescence polarization immunoassay (acetaminophen and salicylic acid). Therefore, the present CZE analysis could provide a simple, rapid, and efficient method for the identification as well as monitoring of analgesic antiinflammatory agents, particularly in serum of patients suffering from intoxication by overdosage of these agents.

  12. [Simultaneous separation and determination of vanillin and o-vanillin by capillary zone electrophoresis]. (United States)

    Chen, Xing; Guan, Jin; Wang, Huize; Li, Yun; Shi, Zhe


    A method for the simultaneous separation and determination of vanillin and o-vanillin by capillary zone electrophoresis (CZE) was developed. The influences of type, concentration and pH of running buffer, and applied voltage on separation were investigated. Under the conditions of 50 mmol/L borax-150 mmol/L disodium hydrogen phosphate (pH 7.5) and applied voltage of 15 kV, the vanillin and o-vanillin were separated in 6 min. The method was proved to be robust through verification of accuracy, precision and linearity. The calibration curves of vanillin and o-vanillin showed good linearity in the range of 10-240 mg/L, and the correlation coefficients were 0.999 9 and 0.999 7, respectively. The limits of detection for vanillin and o-vanillin were 1.0 mg/L (S/N = 3). The average recoveries at three spiked levels were 99.4%-101.2% with acceptable relative standard deviations of 0.19%-0.73%. The method has been successfully used for the determination of vanillin and o-vanillin in real samples, and the assay results are satisfactory.

  13. Determination of Four Active Ingredients in Vc Yinqiao Tablets by Capillary Zone Electrophoresis with Amperometric Detection

    Institute of Scientific and Technical Information of China (English)

    L(U),Jin; WANG,Qing-Jiang; CHENG,Xi; LIU,Hai-Yan; HE,Pin-Gang; FANG,Yu-Zhi


    A simple, reliable and reproducible method, based on capillary zone electrophoresis with amperometric detection (CZE-AD), has been developed for simultaneous determination of four active ingredients in Vc Yinqiao tablets including paracetamol, vitamin C, caffeic acid and chlorogenic acid. A carbon-disk electrode was used as working electrode and 0.95 V (versus SCE) was selected as detection potential. The optimal conditions of CZE experiment were 30 mmol·L-1 borate solution (pH 9.5) as running buffer, 14 kV as separation voltage and 8 s (14 kV) as electro-kinetic sampling time. Under the selected optimum conditions, paracetamol, vitamin C, caffeic acid and chlorogenic acid could be perfectly separated within 22 min, and their detection limits (S/N=3) ranged from 5 × 10-7 to 1×10-6 mol·L-1. This proposed method demonstrated good reproducibility with relative standard deviations of less than 3% for both migration time and peak current (n=7). The utility of this method was demonstrated by monitoring a kind of compound medicine named Vc Yinqiao tablets and the assay results were satisfactory.

  14. Determination of L-ascorbic acid in Lycopersicon fruits by capillary zone electrophoresis. (United States)

    Galiana-Balaguer, L; Roselló, S; Herrero-Martínez, J M; Maquieira, A; Nuez, F


    This study shows an improved method for the determination of L-ascorbic acid (l-AA) in fruits of Lycopersicon by capillary zone electrophoresis (CZE). Two backgrounds electrolytes (BGEs) have been tested: (i) 400 mM borate at pH 8.0 and 1 x 10(-2)% hexadimethrine bromide, for the separation of Eulycopersicon subgenus species; and (ii) as in BGE(i) but supplemented with 20% (v/v) acetonitrile, for the separation of species of the Eriopersicon subgenus. The present procedures were compared with two routine methods-enzymatic assay and potentiometric titration with 2,6-dichlorophenol-indophenol. While these routine methods presented some difficulties in quantifying l-AA in several Lycopersicon fruits, CZE was successfully applied in all the analyzed samples. The proposed CZE protocols give lower detection limits (<0.4 microg ml(-1)); are cheaper, quicker, and highly reproducible; and can be applied to analyze large series of samples (ca. 50 samples per day) which is utmost importance, not only in screening trials for internal quality and tomato breeding programs, but also in systematic and routine characterization of Lycopersicon fruits.

  15. Screening of chemokine receptor CCR4 antagonists by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Zhe Sun; Lin-Jie Tian; Qian Lin; Xiao-Mei Ling; Jun-Hai Xiao; Ying Wang


    Abstract CC chemokine receptor 4 (CCR4) is a kind of G-protein-coupled receptor, which plays a pivotal role in allergic inflammation. The interaction between 2-(2-(4-chloro-phenyl)-5-{[(naphthalen-1- ylmethyl)-carbamlyl]-methyl-4-oxo-thiazolidin-3-yl)-N-(3-morpholin-4-yl-propyi)-acetamide (S009) and the N-terminal extracellular tail (ML40) of CCR4 has been validated to be high affinity by capillary zone electrophoresis (CZE).The S009 is a known CCR4 antagonist. Now, a series of new thiourea derivatives have been synthesized. Compared with positive control S009, they were screened using ML40 as target by CZE to find some new drugs for allergic inflammation diseases. The synthesized compounds XJH-5, XJH-4, XJH-17 and XJH-1 displayed the interaction with ML40, but XJH-9, XJH-10, XJH-I 1, XJH-12, XJH-13, XJH-14, XJH-3, XJH-8, XJH-6, XJH-7, XJH-15, XJH-16 and XJH-2 did not bind to ML40. Both qualification and quantification characterizations of the binding were determined. The affinity of the four compounds was valued by the binding constant, which was similar with the results of chemotactic experiments. The established CEZ method is capable of sensitive and fast screening for a series of lactam analogs in the drug discovery for allergic inflammation diseases.

  16. [Selection of back-ground electrolyte in capillary zone electrophoresis by triangle and tetrahedron optimization methods]. (United States)

    Sun, Guoxiang; Song, Wenjing; Lin, Ting


    The triangle and tetrahedron optimization methods were developed for the selection of back-ground electrolyte (BGE) in capillary zone electrophoresis (CZE). Chromatographic fingerprint index F and chromatographic fingerprint relative index F(r) were used as the objective functions for the evaluation, and the extract of Saussurea involucrate by water was used as the sample. The BGE was composed of borax, boric acid, dibasic sodium phosphate and sodium dihydrogen phosphate solution with different concentrations using triangle and tetrahedron optimization methods. Re-optimization was carried out by adding organic modifier to the BGE and adjusting the pH value. In triangle method, when 50 mmol/L borax-150 mmol/L sodium dihydrogen phosphate (containing 3% acetonitrile) (1 : 1, v/v) was used as BGE, the isolation was considered to be satisfactory. In tetrahedron method, the best BGE was 50 mmol/L borax-150 mmol/L sodium dihydrogen phosphate-200 mmol/L boric acid (1 : 1 : 2, v/v/v; adjusting the pH value to 8.55 by 0.1 mol/L sodium hydroxide). There were 28 peaks and 25 peaks under the different conditions respectively. The results showed that the methods could be applied to the selection of BGE in CZE of the extract of traditional Chinese medicine by water or ethanol.

  17. [Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis]. (United States)

    Zhang, Yiding; Chang, Cuilan; Guo, Qilei; Cao, Hong; Bai, Yu; Liu, Huwei


    A novel analytical method for tartrazine aluminum lake and sunset yellow aluminum lake using capillary zone electrophoresis (CZE) was studied. The pigments contained in the color lakes were successfully separated from the aluminum matrix in the pre-treatment process, which included the following steps: dissolve the color lakes in 0.1 mol/L H2SO4, adjust the pH of the solution to 5.0, then mix it with the solution of EDTA x 2Na and heat it in a water bath, then use polyamide powder as the stationary phase of solid phase extraction to separate the pigments from the solution, and finally elute the pigments with 0.1 mol/L NaOH. The CZE conditions systematically optimized for tartrazine aluminum lake were: 48.50 cm of a fused silica capillary with 40.00 cm effective length and 50 microm i. d., the temperature controlled at 20.0 degrees C, 29.0 kV applied, HPO4(2-)-PO4(3-) (0.015 mol/L, pH 11.45) solution as running buffer, detection at 263 nm. The conditions for sunset yellow aluminum lake were: the same capillary and temperature, 25.0 kV applied, HPO4(2-)-PO4(3-) (0.025 mol/L, pH 11.45) solution as running buffer, detection at 240 nm. The limits of detection were 0.26 mg/L and 0.27 mg/L, and the linear ranges were 0.53-1.3 x 10(2) mg/L and 0.54-1.4 x 10(2) mg/L for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. The RSDs were 4.3% and 5.7% (run to run, n = 6), 5.6% and 6.0% (day to day, n = 6) for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. Further developments for this method could make it a routinely used method analyzing color lakes in foods.

  18. Capillary Zone Electrophoresis Investigation of Interactions between Granulocyte-colony Stimulating Factor and Dextran Sulfate / Carrageenan Oligosaccharide

    Institute of Scientific and Technical Information of China (English)

    Ai Ye LIANG; Yu Guang DU; Ke Yi WANG; Bing Cheng LIN


    The interactions between granulocyte-colony stimulating factor (G-CSF) and dextran sulfate / κ-carrageenan oligosa1ccharide were studied by capillary zone electrophoresis. Dextran sulfate could strongly interact with G-CSF and the complex was detected. The binding constant and stoichiometry were determined to be 1.2x106 (mol/L)-1 and 3:1, respectively. However, the interaction between κ-carrageenan oligosaccharide and G-CSF was not found.

  19. Evaluation of capillary zone electrophoresis for the determination of protein composition in therapeutic immunoglobulins and human albumins. (United States)

    Christians, Stefan; van Treel, Nadine Denise; Bieniara, Gabriele; Eulig-Wien, Annika; Hanschmann, Kay-Martin; Giess, Siegfried


    Capillary zone electrophoresis (CZE) provides an alternative means of separating native proteins on the basis of their inherent electrophoretic mobilities. The major advantage of CZE is the quantification by UV detection, circumventing the drawbacks of staining and densitometry in the case of gel electrophoresis methods. The data of this validation study showed that CZE is a reliable assay for the determination of protein composition in therapeutic preparations of human albumin and human polyclonal immunoglobulins. Data obtained by CZE are in line with "historical" data obtained by the compendial method, provided that peak integration is performed without time correction. The focus here was to establish a rapid and reliable test to substitute the current gel based zone electrophoresis techniques for the control of protein composition of human immunoglobulins or albumins in the European Pharmacopoeia. We believe that the more advanced and modern CZE method described here is a very good alternative to the procedures currently described in the relevant monographs.

  20. Derivatization in Capillary Electrophoresis. (United States)

    Marina, M Luisa; Castro-Puyana, María


    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS).

  1. Gold nanoparticles deposited capillaries for in-capillary microextraction capillary zone electrophoresis of monohydroxy-polycyclic aromatic hydrocarbons. (United States)

    Wang, Huiyong; Knobel, Gaston; Wilson, Walter B; Calimag-Williams, Korina; Campiglia, Andres D


    This article presents the first application of gold nanoparticles deposited capillaries as pre-concentration devices for in-capillary microextraction CZE and their use for the analysis of monohydroxy-polycyclic aromatic hydrocarbons in synthetic urine samples. The successful separation of 1-hydroxypyrene, 9-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene (3-OHbap), 4-hydroxybenzo[a]pyrene and 5-hydroxybenzo[a]pyrene under a single set of electrophoretic conditions is demonstrated as well as the feasibility to obtain competitive ultraviolet absorption LOD with commercial instrumentation. Enrichment factors ranging from 87 (9-OHphe) to 100 (3-OHbap) made it possible to obtain LOD ranging from 9 ng/mL (9-OHphe and 3-OHbap) to 14 ng/mL (4-hydroxybenzo[a]pyrene).

  2. Capillary zone electrophoresis analysis and detection of mid-spectrum biological warfare agents. Suffield memorandum No. 1463

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, C.A.


    Mid-spectrum biological warfare agents such as proteins, peptides, and toxins are often difficult to analyze and often require individually developed assay methods for detection and identification. In this regard, capillary electrophoresis is an important, emerging technique for separation and quantitation of peptides and proteins, providing separation efficiencies up to two orders of magnitude greater than high performance liquid chromatography. The technique can also analyze a broad range of compounds, has a simple instrument design which can be automated, and has low sample volume requirements. In this study, a highly efficient and reproducible capillary zone electrophoresis method was developed to separate and identify a series of nine peptides of defense interest including bradykinin, leucine enkephalin, and oxytocin. The paper demonstrates three strategies which could be used in a fully automated field detection and identification system for unknown peptides.

  3. Diagnosis of a rare double heterozygous Hb D Punjab/Hb Q India hemoglobinopathy using Sebia capillary zone electrophoresis

    Directory of Open Access Journals (Sweden)

    Sushama Parab


    Full Text Available In India, hemoglobinopathies constitute a major genetic disorder and hemoglobin variants such as Hb S, Hb D Punjab, and Hb E are the most common ones. Other variants include Hb Q India, Hb Lepore, Hb J Meerut, Hb D Iran, etc. These variants show heterozygous state along with beta thalassemia. However, compound heterozygosities among these variants are very rare. Ethylenediaminetetraacetic acid whole blood sample received for routine thalassemia screening was subjected to alkaline electrophoresis using automated capillary zone electrophoresis. Suspecting the presence of rare variants, further analysis was carried out using Bio-Rad D10 and Tosoh G8 high-performance liquid chromatography (HPLC systems. Capillary zone electrophoretograms showed the presence of peaks in zone Hb A, Hb D, a fused peak in Hb A2, and a small peak in Z1 zone. Bio-Rad and Tosoh chromatograms also indicated the presence of four peaks which are identified as Hb A, Hb D Punjab, Hb Q India, and hybrid of Hb D Punjab/Hb Q India. A peak in Hb D zone of capillary was due to co-migration of Hb D Punjab and Hb Q India variants. Small peak in Z1 zone indicated the presence of alpha chain variant Hb Q India. The findings were further confirmed by HPLC results and molecular genetic studies. The present study reports for the 1 st time a rare hemoglobinopathy of double heterozygosity for Hb D Punjab, Hb Q India on Capillarys 2 Flex Piercing analyzer and is forth reported case for this rare hemoglobinopathy.

  4. New electrolyte systems for capillary zone electrophoresis of metal cations and non-ionic organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y.


    Excellent separations of metal ions can be obtained very quickly by capillary electrophoresis provided a weak complexing reagent is incorporated into the electrolyte to alter the effective mobilities of the sample ions. Indirect photometric detection is possible by also adding a UV-sensitive ion to the electrolyte. Separations are described using phthalate, tartrate, lactate or hydroxyisobutyrate as the complexing reagent. A separation of twenty-seven metal ions was achieved in only 6 min using a lactate system. A mechanism for the separation of lanthanides is proposed for the hydroxyisobutyrate system.

  5. A comparative study of capillary zone electrophoresis and pH-potentiometry for determination of dissociation constants. (United States)

    Andrasi, Melinda; Buglyo, Peter; Zekany, Laszlo; Gaspar, Attila


    Acidity constants of six cephalosporin antibiotics, cefalexin, cefaclor, cefadroxil, cefotaxim, cefoperazon and cefoxitin are determined using capillary zone electrophoresis (CZE) and pH-potentiometric titrations. Since CZE is a separation method, it is not necessary for the samples to be of high purity and known concentration because only mobilities are measured. The effect on determination of dissociation constants of different matrices (serum, 0.9% NaCl, fermentation matrix) was examined. The advantages of CZE can be utilized in those fields where potentiometry has limitations (sample quantity, solubility, purity, simultaneous determinations), although pK(a) values that are close to each other can be determined by potentiometry with more accuracy.

  6. Characterization and stability of gold nanoparticles depending on their surface chemistry: Contribution of capillary zone electrophoresis to a quality control. (United States)

    Pallotta, Arnaud; Boudier, Ariane; Leroy, Pierre; Clarot, Igor


    Four kinds of gold nanoparticles (AuNP) quite similar in terms of gold core size (ca. 5nm) and shape (spherical) but differing by their surface chemistry (either negatively, or positively charged, or neutral) were synthesized. They were analyzed using both the classical physicochemical approach (spectrophotometry, dynamic light scattering coupled or not to electrophoresis and transmission electron microscopy) and capillary zone electrophoresis equipped with photodiode array detection. The results obtained by both methodologies (related to Surface Plasmon Band-maximal absorbance wavelength-, and zeta potential and electrophoretic mobilities) were well correlated. Moreover, taking advantage of the separation method, the sample heterogeneity was evaluated and an impurity profile was extracted. This allowed setting some specifications which were then applied on the one hand to a batch-to-batch survey to declare NP as conform or not after production and on the other hand to a stability study.

  7. Analysis of Phenolic Compounds in Coke Plant Wastewater by Capillary Zone Electrophoresis with Inhibited Chemiluminescence Detection

    Institute of Scientific and Technical Information of China (English)

    Xiang Dong XU; Yong Gang HU; Ze Yu YANG


    A capillary electrophoresis(CE) with on-line inhibited chemiluminescence (CL) detection was firstly used for the simultaneous analysis of benzenediol isomers and phenol. It is based on the quenching effect of benzenediol isomers and phenol on the chemiluminescence reaction of luminol with potassium ferricyanide in sodium hydroxide medium. Under the optimum conditions, the four phenols were baseline separated and detected in less than 10 min.The detection limits (S/N=3) for hydroquinone, resorcinol, catechol and phenol were 2.9×10-8mol/L, 3.7×10-7 mol/L, 8.4×10-8 mol/L and 4.4×10-6 mol/L, respectively. Finally, the presented method has been successfully applied to real sample.

  8. Separation of arginase isoforms by capillary zone electrophoresis and isoelectric focusing in density gradient column. (United States)

    Pedrosa, M M; Legaz, M E


    Four major arginase isoforms, I, II, III and IV, have been detected in Evernia prunastri thallus. They differ in terms of both physical and biochemical properties. The isoelectric point (pI) of these proteins has been determined by both isoelectric focusing in density gradient column and high-performance capillary electrophoresis (HPCE). Isoelectric focusing revealed charge microheterogeneity for isoforms II and IV whereas arginases I and II had the same pI value of 5.8. HPCE separation confirmed this charge microheterogeneity for isoform IV but not for isoform III, and provided evidence of microheterogeneity for isoforms I and II. The effect of various electrolyte buffers and running conditions on the HPCE separation of arginase isoform were investigated. Addition of 0.5 mM spermidine (SPD) to the running buffer reduced the electroosmotic flow (EOF) and permitted discriminating between the native proteins and protein fragments.

  9. Biomedical applications of capillary electrophoresis (United States)

    Kartsova, L. A.; Bessonova, E. A.


    The review deals with modern analytical approaches used in capillary electrophoresis for solving medical and biological problems: search for biomarkers of various diseases and rapid diagnosis based on characteristic profiles of biologically active compounds by capillary electrophoresis with mass spectrometric detection; monitoring of the residual drugs in biological fluids for evaluating the efficiency of drug therapy; testing of the enantiomeric purity of pharmaceutical products; the use of novel materials as components of stationary and pseudo-stationary phases in capillary electrophoresis and capillary electrochromatography to increase the selectivity of separation of components of complex matrices; and identification of various on-line preconcentration techniques to reduce the detection limits of biologically active analytes. A topical trend in capillary electrophoresis required in clinical practice, viz., the design of microfluidic systems, is discussed. The bibliography includes 173 references.

  10. Validated Method for the Determination of Piroxicam by Capillary Zone Electrophoresis and Its Application to Tablets

    Directory of Open Access Journals (Sweden)

    Arın Gül Dal


    piroxicam in tablets. The separation of piroxicam was conducted in a fused-silica capillary by using 10 mM borate buffer (pH 9.0 containing 10% (v/v methanol as background electrolyte. The optimum conditions determined were 25 kV for separation voltage and 1 s for injection time. Analysis was carried out with UV detection at 204 nm. Naproxen sodium was used as an internal standard. The method was linear over the range of 0.23–28.79 µg/mL. The accuracy and precision were found to be satisfied within the acceptable limits (<2%. The LOD and LOQ were found to be 0.07 and 0.19 µg/mL, respectively. The method described here was applied to tablet dosage forms and the content of a tablet was found in the limits of USP-24 suggestions. To compare the results of capillary electrophoretic method, UV spectrophotometric method was developed and the difference between two methods was found to be insignificant. The capillary zone electrophoretic method developed in this study is rapid, simple, and suitable for routine analysis of piroxicam in pharmaceutical tablets.

  11. Determination of amitrole and urazole in water samples by capillary zone electrophoresis using simultaneous UV and amperometrical detection. (United States)

    Chicharro, M; Moreno, M; Bermejo, E; Ongay, S; Zapardiel, A


    In this paper, capillary zone electrophoresis with amperometric detection (CZE-AD) was first applied to the simultaneous separation and determination of amitrole and urazole in water samples. A simple end-column electrochemical detector was used in combination with a commercially available capillary electrophoresis instrument with UV detection. The effects of several important factors were investigated to find optimum conditions. A carbon disk electrode was used as working electrode. Separation and determination of these compounds in water samples were performed in 0.030 mol l(-1) acetate buffers at pH 4.5, 25 kV as separation voltage and the samples were introduced by hydrodynamic mode for 1.5 s. Most of the studies realized showed that the direct electrochemical detection is more sensitive and selective than UV detection. Under the optimum conditions, excellent linearity was observed between peak amperometric signal and analyte concentrations in the range of 0.19-1.35 mg l(-1) for amitrole and 0.20-1.62 mg l(-1) for urazole. The detection limits were 63 and 68 microg l(-1) for amitrole and urazole, respectively. The utility of this method was demonstrated by monitoring water samples, and the assay results were satisfactory. The detection limits using a previous preconcentration step for amitrole and urazole in spiked mineral water samples were 0.6 and 1.0 microg l(-1) for amitrole and urazole, respectively.

  12. Enantioselective analysis of fluoxetine in pharmaceutical formulations by capillary zone electrophoresis

    Directory of Open Access Journals (Sweden)

    Melania Cârcu-Dobrin


    Full Text Available Fluoxetine is an antidepressant, a selective serotonin reuptake inhibitor (SSRI used primarily in the treatment of major depression, panic disorder and obsessive compulsive disorder. Chiral separation of racemic fluoxetine is necessary due to its enantioselective metabolism. In order to develop a suitable method for chiral separation of fluoxetine, cyclodextrin (CD modified capillary electrophoresis (CE was employed. A large number of native and derivatized, neutral and ionized CD derivatives were screened to find the optimal chiral selector. As a result of this process, heptakis(2,3,6-tri-O-methyl-β-CD (TRIMEB was selected for enantiomeric discrimination. A factorial analysis study was performed by orthogonal experimental design in which several factors are varied at the same time to optimize the separation method. The optimized method (50 mM phosphate buffer, pH = 5.0, 10 mM TRIMEB, 15 °C, + 20 kV, 50 mbar/1 s, detection at 230 nm was successful for baseline separation of fluoxetine enantiomers within 5 min. Our method was validated according to ICH guidelines and proved to be sensitive, linear, accurate and precise for the chiral separation of fluoxetine.

  13. DNA typing by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, N.


    Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

  14. Determination of Five Organic Acids in Radix Isatidis by Column Partition Chromatography and Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    CHAIYi-fen; JISong-gang; ZHANGGuo-qing; LIUChang-hai


    Aim To determine five organic acids in Radix lsatidis. Method The extraction method and the column partition chromatographic conditiom were studied. Then a capillary zone dectrophorefic method was set up for the determina-tion. Results The linear ranges of quinazolinone acid, n-anthranilic acid, benzoic acid, salicylic acid, and syringic acid were 5.52 - 92.0μg·mL-1 , 5.12 - 102μg·mL-1 , 2.28 - 84.4μg·mL-1, 4.78 - 159 μg·mL-1, and 1.74- 87.0μg·mL-1 respectively. Conclusion The established method is accurate and simple.

  15. Capillary zone electrophoresis for determination of vildagliptin (a DPP-4 inhibitor) in pharmaceutical formulation and comparative study with HPLC. (United States)

    Barden, A T; Piccoli, B L; Volpato, N M; Schapoval, E E S; Steppe, M


    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the determination of vildagliptin (VLG) in pharmaceutical dosage forms using ranitidine hydrochloride (RH) as internal standard. The CZE method was carried out in a fused silica capillary (64.5 cm total length and 56.0 cm effective length, 50 microm i.d.) by applying a potential of 25 kV (positive polarity), hydrodynamic injection by 50 mbar for 5 s and the temperature of the capillary cartridge was 25 degreesC. The selected background electrolyte (BGE) consisted of 25 mM potassium phosphate (pH 8.0) with UV/PDA detection at 207 nm. The electrophoretic separation was obtained within 6 min and was linear in the range of 50-200 microg/mL (r= 0.9994). The specificity and the stability-indicating capability were demonstrated through degradation studies, which also showed that there was no interference of the formulation excipients. The method was validated in accordance to ICH guidelines acceptance criteria for specificity, linearity, precision, accuracy, robustness and system suitability. The proposed method was compared with HPLC method previously validated for this drug, and statistical analysis showed no significant difference between the methods.

  16. Determination of synthetic dyes in food products by capillary zone electrophoresis in a hydrodynamically closed separation compartment. (United States)

    Masár, M; Kaniansky, D


    The application of capillary zone electrophoresis (CZE) in a hydrodynamically closed separation system to determine synthetic food colorants added to food products was investigated. The CZE separations were carried out in a 300-micron-i.d. capillary tube made of fluorinated ethylene-propylene copolymer. The inner diameter of the capillary tube made it possible to enhance sample loads (100-nL injection volumes) so that 10-300 ppb limits of detection (LOD) values could be achieved for the studied dyes by a photometric absorbance detector operating at a 254-nm detection wave-length. With the exception of erythrosine (which exhibited a residual adsorption), very good reproducibilities of the determination were typical for 4- and 32-ppm concentrations of the dyes. This rapid CZE procedure (migration times of the resolved analytes were between 2.5 and 10.5 min) provided good selectivities in the determination of the dyes in various food matrices (soft drink concentrates, liqueurs, and chewing gums). Simple sample preparation steps were effective for the sample matrices used in the investigation.

  17. Study of Interaction between Red-tide Toxin, Domoic Acid and Double -stranded DNA by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Da Zhi LI; Xin Ya HE; Hui WANG; Li SUN; Bing Cheng LIN


    The interactions between amnesic red-tide toxin, domoic acid (DA) and 14mer double-stranded DNA (dsDNA with three kinds of sequences) were studied by capillary zone electrophoresis (CZE). For the dsDNA with a sequence of 5'-CCCCCTATACCCGC-3', the amount of free dsDNA decreases with the increase of added DA; and the signal of DA-dsDNA complex was observed. Meanwhile, the other two dsDNAs, 5'-(C)12GC-3' and 5'-(AT)7-3', the existence of DA could not lead to the change of dsDNA signal and indicated that there is no interaction between DA and these two dsDNAs.

  18. Rapid differentiation of commercial juices and blends by using sugar profiles obtained by capillary zone electrophoresis with indirect UV detection. (United States)

    Navarro-Pascual-Ahuir, María; Lerma-García, María Jesús; Simó-Alfonso, Ernesto F; Herrero-Martínez, José Manuel


    A method for the determination of sugars in several fruit juices and nectars by capillary zone electrophoresis with indirect UV-vis detection has been developed. Under optimal conditions, commercial fruit juices and nectars from several fruits were analyzed, and the sugar and cyclamate contents were quantified in less than 6 min. A study for the detection of blends of high-value juices (orange and pineapple) with cheaper alternatives was also developed. For this purpose, different chemometric techniques, based on sugar content ratios, were applied. Linear discriminant analysis showed that fruit juices can be distinguished according to the fruit type, juice blends also being differentiated. Multiple linear regression models were also constructed to predict the adulteration of orange and pineapple juices with grape juice. This simple and reliable methodology provides a rapid analysis of fruit juices of economic importance, which is relevant for quality control purposes in food industries and regulatory agencies.

  19. Determination of the Acid-Base Dissociation Constant of Acid-Degradable Hexamethylenetetramine by Capillary Zone Electrophoresis. (United States)

    Takayanagi, Toshio; Shimakami, Natsumi; Kurashina, Masashi; Mizuguchi, Hitoshi; Yabutani, Tomoki


    The acid-base equilibrium of hexamethylenetetramine (hexamine) was analyzed with its effective electrophoretic mobility by capillary zone electrophoresis. Although hexamine is degradable in a weakly acidic aqueous solution, and the degraded products of ammonia and formaldehyde can be formed, the effective electrophoretic mobility of hexamine was measured in the pH range between 2.8 and 6.9. An acid-base dissociation equilibrium of the protonated hexamine was analyzed based on the mobility change, and an acid dissociation constant of pKa = 4.93 ± 0.01 (mean ± standard error, ionic strength: 0.020 mol dm(-3)) was determined. The monoprotic acid-base equilibrium of hexamine was confirmed through comparisons of its electrophoretic mobility with the N-ethylquinolinium ion and with the monocationic N-ethyl derivative of hexamine, as well as a slope analysis of the dissociation equilibrium.

  20. Simultaneous analysis of acidulants and preservatives in food samples by using capillary zone electrophoresis with indirect UV detection. (United States)

    Yoshikawa, Kenji; Saito, Shintaro; Sakuragawa, Akio


    Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of acidulants and preservatives in food samples. When a solution of tris (hydroxymethyl) aminomethane, trimellitic acid and poly (vinyl alcohol) was used as the background electrolyte, the nine acidulants and four preservatives listed in the Japanese Food Sanitation Law were detected within 8min. The calibration curves plotted from the peak height of each analyte were linear with a correlation coefficient of 0.99. The relative standard deviations (n=10) of the peak height ranged from 1.2% to 4.7%. The detection limits for these species ranged from 0.6 to 5.3mg/L at a signal-to-noise ratio of three. The method developed method was applied to the simultaneous analysis of acidulants and preservatives in a wide variety of food samples.

  1. Analysis of Amino Acids in a Single Human Red Blood Cell by Capillary Zone Electrophoresis with Intracellular NDA—derivatization and Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    QianDONG; XiaoLeiWANG; 等


    A novel method for determination of amino acids in individual red blood cells has been developed. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by electroporation. After completion of derivatization,the amino acids in a single cell is determined by capillary zone electrophoresis with end-column amperometric detection.

  2. Analysis of Amino Acids in a Single Human Red Blood Cell by Capillary Zone Electrophoresis with Intracellular NDA derivatization and Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)


    A novel method for detcrmination of amino acids in individual human red blood cells has been dcveloped. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by clcctroporation. After completion of derivatization, the amino acids in a single cell is determined by capillary zone electrophoresis with end-column ampcrometric detection.

  3. On-line capillary isotachophoresis-capillary zone electrophoresis analysis of bromate in drinking waters in an automated analyzer with coupled columns and photometric detection. (United States)

    Marák, Jozef; Staňová, Andrea; Vaváková, Veronika; Hrenáková, Martina; Kaniansky, Dušan


    A new, sensitive, and robust analytical method based on capillary zone electrophoresis with on-line capillary isotachophoresis sample pretreatment (ITP-CZE) using a column-coupling (CC) arrangement of automated capillary electrophoretic analyzer was developed for determination of bromate in different type of drinking water samples. Both columns were provided with contact-less conductivity detectors and in CZE step UV detection at 200 nm wavelength was used. Electroosmotic flow of the buffer solutions was suppressed with the addition of 0.1% or 0.05% (m/v) methylhydroxyethylcellulose into the leading and terminating electrolyte, respectively. Hydrodynamic and electroosmotic flows of the buffer solutions were successfully suppressed and therefore, only the electrophoretic transport of ions was significant. Limit of detection for bromate approaching 0.6 μg/L was achieved. Good repeatabilities of migration time (RSD less than 0.3%) and peak area (RSD less than 4.0%) at concentration level 1 μg/L were obtained. Robustness of proposed ITP-CZE method and validation parameters were evaluated. Developed automated ITP-CZE method was applied to the determination of bromate in drinking water samples with different content of inorganic macroconstituents without the need of further sample preparation.

  4. Capillary Zone Electrophoresis with Amperometric Detection for Composition Analysis of Laminarin

    Institute of Scientific and Technical Information of China (English)

    王清江; 丁飞; 李辉; 何品刚; 方禹之


    The composition of laminartn was firstly determined by analyz-ing its hydrolysis monosaccharides with capillary zone elec.lected opamum conditions, fucose, galactose, glucose, man-nose and xylose, which are hydrolysis products of iaminarin,could be perfectly separated within 20 min and showed signifi-cant current responses at copper electrodes. The linear ranges of fucose, galactose and glucose were from 1.0 × 10-6 to 2.0 ×10-4 mol·L-1, those of mannose and xylose were from 1.0×10-6 to 2.0× 10-4 mol·L-1, and their detect/on limits were at 10-7mol·L-1 level (S/N =3). The molar ratio of fucose,galactose,glucose,mannose and xylose in laminartn was 10.5:2.8:1.0:7.3:3.4 and the purity of this polysaccharide leached by the introduced leaching method was 95.7%. Compared to usual UV-vis and other spectrometric methods, analyzing polysaccharide by this method has some merit sof quickness,low-volume sampling,simple instrumentation,high sensitivity and high reproducibility.

  5. A High Voltage Power Supply That Mitigates Current Reversals in Capillary Zone Electrophoresis-Electrospray Mass Spectrometry (United States)

    Flaherty, Ryan J.; Sarver, Scott A.; Sun, Liangliang; Brownell, Greg A.; Go, David B.; Dovichi, Norman J.


    Capillary electrophoresis coupled with electrospray ionization typically employs two power supplies, one at each end of the capillary. One power supply is located at the proximal (injection) end of the capillary. The power supply located at the distal (detector) end of the capillary drives the electrospray. Electrophoresis is driven by the difference in potential between these power supplies. Separations that employ large capillary inner diameter, high conductivity background electrolyte, and high separation potentials generate higher current than that produced by the electrospray. Excess current flows through the electrospray power supply. Most power supplies are not designed to sink current, and the excess current will cause the electrospray voltage to deviate from its set point. We report a simple circuit to handle this excess current, allowing separations under a wide range of electrophoretic conditions.

  6. [Rapid determination of lactose, sucrose, glucose and fructose in foods by capillary zone electrophoresis with indirect ultraviolet detection]. (United States)

    Zhang, Huanhuan; Li, Jiang; Zhao, Shan; Ding, Xiaojing; Wang, Zhi


    A new and rapid method for the simultaneous determination of lactose, sucrose, glucose and fructose by capillary zone electrophoresis ( CZE) with indirect ultraviolet detection was developed. The separation was completed with an uncoated fused-silica capillary with 30.2 cm of total length (effective length of 20 cm) x 50 µm. The separation buffer consisted of 4 mmol/L potassium sorbate, 10 mmol/L sodium phosphate, 30 mmol/L NaOH (pH 12. 56) and 0. 5 mmol/L hexadecytrimethylammonium bromide (CTAB). The separation was performed at a voltage of -8 kV with the ultraviolet detection at 254 nm. The analysis of the four carbohydrates was completed within 10 min. The limits of detection (S/N= 3) for lactose, sucrose, glucose and fructose were 50, 75, 25 and 25 mg/L, and the limits of quantification (S/N = 10) were 150, 225, 75 and 75 mg/L, respectively. The average recoveries for the four carbohydrates were in the range of 87.0%-107.0% with the relative standard deviations of 1.2%-4.7%. No organic solvent was consumed throughout the whole process of the analysis. The method was used for the analysis of nine food samples and a quality control sample. The results demonstrated that the method is simple, rapid, accurate, and suitable for the routine analysis of the four carbohydrates in food samples.

  7. Capillary zone electrophoresis for analysis of phytochelatins and other thiol peptides in complex biological samples derivatized with monobromobimane. (United States)

    Perez-Rama, Mónica; Torres Vaamonde, Enrique; Abalde Alonso, Julio


    A new method to improve the analysis of phytochelatins and their precursors (cysteine, gamma-Glu-Cys, and glutathione) derivatized with monobromobimane (mBrB) in complex biological samples by capillary zone electrophoresis is described. The effects of the background electrolyte pH, concentration, and different organic additives (acetonitrile, methanol, and trifluoroethanol) on the separation were studied to achieve optimum resolution and number of theoretical plates of the analyzed compounds in the electropherograms. Optimum separation of the thiol peptides was obtained with 150 mM phosphate buffer at pH 1.60. Separation efficiency was improved when 2.5% v/v methanol was added to the background electrolyte. The electrophoretic conditions were 13 kV and capillary dimensions with 30 cm length from the inlet to the detector (38 cm total length) and 50 microm inner diameter. The injection was by pressure at 50 mbar for 17 s. Under these conditions, the separation between desglycyl-peptides and phytochelatins was also achieved. We also describe the optimum conditions for the derivatization of biological samples with mBrB to increase electrophoretic sensitivity and number of theoretical plates. The improved method was shown to be simple, reproducible, selective, and accurate in measuring thiol peptides in complex biological samples, the detection limit being 2.5 microM glutathione at a wavelength of 390 nm.

  8. Development and validation of a simple determination of urine metabolites (oxalate, citrate, uric acid and creatinine) by capillary zone electrophoresis. (United States)

    Muñoz, Jose A; López-Mesas, Montserrat; Valiente, Manuel


    Oxalate, citrate, uric acid and creatinine are important urine markers for the evaluation and treatment of urolithiasic patients. They have been traditionally analysed by enzymatic and chromatographic techniques which present practical drawbacks, mainly in the sample pre-treatment step. The purpose of this study was to evaluate those markers in urine samples, by an easy multi-analyte assay using capillary zone electrophoresis. The four urine metabolites were determined, at 25 degrees C, by using a 50 cm x 75 microm capillary in 50 mmol l(-1) phosphate buffer (pH 6.5), at constant voltage of -30 kV and UV detection at 195 nm (for oxalate and citrate) or 30 kV and 234 nm (for creatinine and uric acid). The sample pre-treatment was minimum, 5- and 20-fold dilution of the urine sample and acidification to pH 3-4. Validation parameters (linear range, sensitivity, accuracy, precision and detection limits) were statistically comparable to those obtained with the official methods normally used in the clinical practice. The effect of freezing as a conservation method of urine samples is also discussed in terms of recoveries of the analytes. The analytical method developed is highly useful as a diagnostic tool for detecting metabolic renal disorders due to its simplicity, time consuming, easy automation, cost efficiency and analytical effectiveness, accomplishing with the clinical requirements.

  9. Determination of polyphenols in Spanish wines by capillary zone electrophoresis. Application to wine characterization by using chemometrics. (United States)

    Franquet-Griell, Helena; Checa, Antonio; Núñez, Oscar; Saurina, Javier; Hernández-Cassou, Santiago; Puignou, Lluis


    A capillary zone electrophoresis (CZE) method for the simultaneous determination of 20 polyphenols in wine was developed. The separation was performed using fused-silica capillaries of 75 μm i.d. and a 30 mM sodium tretraborate buffer solution at pH 9.2 with 5% isopropanol as a background electrolyte. A capillary voltage of +25 kV with pressure-assisted (3.5 kPa) separation from minute 18 was applied, thus achieving a total analysis time of 0.990), and run-to-run and day-to-day precisions (RSD values lower than 6.5 and 15.7%, respectively) were established. Three different calibration procedures were evaluated for polyphenol quantitation in wines: external calibration using standards prepared in Milli-Q water, standard addition, and pseudomatrix-matched calibration using wine as a matrix. For a 95% confidence level, no statistical differences were observed, in general, between the three calibration methods (p values between 0.11 and 0.84), whereas for some specific polyphenols, such as cinnamic acid, syringic acid, and gallic acid, results were not comparable when external calibration was used. The CZE method using pseudomatrix-matched calibration was then proposed and applied to the analysis of polyphenols in 49 Spanish wines, showing satisfactory results and a wide compositional variation between wines. Electrophoretic profiles and other compositional data (e.g., peak areas of selected peaks) were considered as fingerprints of wines to be used for characterization and classification purposes. The corresponding data were analyzed by principal component analysis (PCA) to extract information on the most significant features contributing to wine discrimination according to their origins. Results showed that a reasonable distribution of wines depending on the elaboration areas was found, tyrosol and gallic, protocatechuic, p-coumaric, and caffeic acids being some representative discriminant compounds.

  10. Hybrid phospholipid bilayer coatings for separations of cationic proteins in capillary zone electrophoresis. (United States)

    Gallagher, Elyssia S; Adem, Seid M; Bright, Leonard K; Calderon, Isen A C; Mansfield, Elisabeth; Aspinwall, Craig A


    Protein separations in CZE suffer from nonspecific adsorption of analytes to the capillary surface. Semipermanent phospholipid bilayers have been used to minimize adsorption, but must be regenerated regularly to ensure reproducibility. We investigated the formation, characterization, and use of hybrid phospholipid bilayers (HPBs) as more stable biosurfactant capillary coatings for CZE protein separations. HPBs are formed by covalently modifying a support with a hydrophobic monolayer onto which a self-assembled lipid monolayer is deposited. Monolayers prepared in capillaries using 3-cyanopropyldimethylchlorosilane (CPDCS) or n-octyldimethylchlorosilane (ODCS) yielded hydrophobic surfaces with lowered surface free energies of 6.0 ± 0.3 or 0.2 ± 0.1 mJ m(-2) , respectively, compared to 17 ± 1 mJ m(-2) for bare silica capillaries. HPBs were formed by subsequently fusing vesicles comprised of 1,2-dilauroyl-sn-glycero-3-phosphocholine or 1,2-dioleoyl-sn-glycero-3-phosphocholine to CPDCS- or ODCS-modified capillaries. The resultant HPB coatings shielded the capillary surface and yielded reduced electroosmotic mobility (1.3-1.9 × 10(-4) cm(2) V(-1) s(-1) ) compared to CPDCS- and ODCS-modified or bare capillaries (3.6 ± 0.2 × 10(-4) cm(2) V(-1) s(-1) , 4.8 ± 0.4 × 10(-4) cm(2) V(-1) s(-1) , and 6.0 ± 0.2 × 10(-4) cm(2) V(-1) s(-1) , respectively), with increased stability compared to phospholipid bilayer coatings. HPB-coated capillaries yielded reproducible protein migration times (RSD ≤ 3.6%, n ≥ 6) with separation efficiencies as high as 200 000 plates/m.

  11. Determination of Amino Acids in Panax notoginseng by Microwave Hydrolysis and Derivatization Coupled with Capillary Zone Electrophoresis Detection

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-tian; ZHAO Ya-jing; JIANG Cheng-fei; ZHANG Han-qi; YU Ai-min


    The microwave hydrolysis and derivatization coupled with capillary electrophoresis detection were developed for the separation and determination of the amino acids in Panax notoginseng.The experimental conditions for the microwave hydrolysis and derivatization were examined and optimized.Several parameters of capillary electrophoresis,such as pH value of background electrolyte,borate concentration and applied voltage were optimized.Under the selected conditions,11 amino acids were completely separated.The real sample was analyzed and the results were satisfactory.Compared with that of conventional heat hydrolysis and derivatization,the analytical time of this method was significantly shortened.

  12. Potential of capillary electrophoresis for the profiling of propolis

    NARCIS (Netherlands)

    Hilhorst, M.J; Somsen, G.W; de Jong, G.J.


    The usefulness of capillary electrophoresis (CE) with diode array detection for the profiling of Propolis, a hive product, is investigated. Water extracts of Propolis were analyzed with both capillary zone electrophoresis (CZE) at pH 7.0 and 9.3, and micellar electrokinetic chromatography (MEKC) wit

  13. Two-dimensional capillary electrophoresis using tangentially connected capillaries. (United States)

    Sahlin, Eskil


    A novel type of fused silica capillary system is described where channels with circular cross-sections are tangentially in contact with each other and connected through a small opening at the contact area. Since the channels are not crossing each other in the same plane, the capillaries can easily be filled with different solutions, i.e. different solutions will be in contact with each other at the contact point. The system has been used to perform different types of two-dimensional separations and the complete system is fully automated where a high voltage switch is used to control the location of the high voltage in the system. Using two model compounds it is demonstrated that a type of two-dimensional separation can be performed using capillary zone electrophoresis at two different pH values. It is also shown that a compound with acid/base properties can be concentrated using a dynamic pH junction mechanism when transferred from the first separation to the second separation. In addition, the system has been used to perform a comprehensive two-dimensional capillary electrophoresis separation of tryptic digest of bovine serum albumin using capillary zone electrophoresis followed by micellar electrokinetic chromatography.

  14. Pneumatic Microvalve-Based Hydrodynamic Sample Injection for High-Throughput, Quantitative Zone Electrophoresis in Capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Ryan T.; Wang, Chenchen; Rausch, Sarah J.; Lee, Cheng S.; Tang, Keqi


    A hybrid microchip/capillary CE system was developed to allow unbiased and lossless sample loading and high throughput repeated injections. This new hybrid CE system consists of a polydimethylsiloxane (PDMS) microchip sample injector featuring a pneumatic microvalve that separates a sample introduction channel from a short sample loading channel and a fused silica capillary separation column that connects seamlessly to the sample loading channel. The sample introduction channel is pressurized such that when the pneumatic microvalve opens briefly, a variable-volume sample plug is introduced into the loading channel. A high voltage for CE separation is continuously applied across the loading channel and the fused silica capillary separation column. Analytes are rapidly separated in the fused silica capillary with high resolution. High sensitivity MS detection after CE separation is accomplished via a sheathless CE/ESI-MS interface. The performance evaluation of the complete CE/ESI-MS platform demonstrated that reproducible sample injection with well controlled sample plug volumes could be achieved by using the PDMS microchip injector. The absence of band broadening from microchip to capillary indicated a minimum dead volume at the junction. The capabilities of the new CE/ESI-MS platform in performing high throughput and quantitative sample analyses were demonstrated by the repeated sample injection without interrupting an ongoing separation and a good linear dependence of the total analyte ion abundance on the sample plug volume using a mixture of peptide standards. The separation efficiency of the new platform was also evaluated systematically at different sample injection times, flow rates and CE separation voltages.

  15. Simultaneous determination of a pyridine-triphenylborane anti-fouling agent and its estimated degradation products using capillary zone electrophoresis. (United States)

    Fukushi, Keiichi; Yakushiji, Yuki; Okamura, Hideo; Hashimoto, Youichi; Saito, Keiitsu


    A commercial organoborane compound, pyridine-triphenylborane (PTPB), is often applied to ship hulls as an anti-fouling agent. We developed capillary zone electrophoresis (CZE) with direct UV detection for the simultaneous determination of PTPB and its estimated degradation products: diphenylborinic acid (DPB), phenylboronic acid (MPB), and phenol. The limits of detection (LODs) for PTPB, DPB, MPB, and phenol were, respectively, 25, 30, 50, and 29 microg/l at a signal-to-noise ratio of three. At concentrations of 0.5mg/l, values of the relative standard deviation (RSD, n=6, intra-day) of peak area were obtained, respectively, for PTPB, DPB, MPB, and phenol, as 4.1, 4.1, 4.7, and 3.4% for peak heights 3.6, 3.2, 1.7, and 1.4%, and for migration times 1.1, 1.1, 1.0, and 0.73%. The analytes were detected within 14 min. Simple photodegradation experiments were conducted to verify the usefulness of the proposed method for additional PTPB degradation investigations.

  16. Capillary zone electrophoresis for fatty acids with chemometrics for the determination of milk adulteration by whey addition. (United States)

    de Oliveira Mendes, Thiago; Porto, Brenda Lee Simas; Bell, Maria José Valenzuela; Perrone, Ítalo Tuler; de Oliveira, Marcone Augusto Leal


    Adulteration of milk with whey is difficult to detect because these two have similar physical and chemical characteristics. The traditional methodologies to monitor this fraud are based on the analysis of caseinomacropeptide. The present study proposes a new approach to detect and quantify this fraud using the fatty acid profiles of milk and whey. Fatty acids C14:0, C16:0, C18:0, C18:1, C18:2 and C18:3 were selected by gas chromatography associated with discriminant analysis to differentiate milk and whey, as they are present in quite different amounts. These six fatty acids were quantified within a short time by capillary zone electrophoresis in a set of adulterated milk samples. The correlation coefficient between the true values of whey addition and the experimental values obtained by this technique was 0.973. The technique is thus useful for the evaluation of milk adulteration with whey, contributing to the quality control of milk in the dairy industry.

  17. Clinical application of a rapid microbiological test based on capillary zone electrophoresis to assess local skin infection

    Directory of Open Access Journals (Sweden)

    Szeliga Jacek


    Full Text Available Abstract Background The basic clinical problem associated with infection treatment is the fact that classic, commonly and routinely used isolation and identification methods are based on long-term processes of a phenotypic analysis of microorganisms. Consequently sometimes, especially in small centres, rapid implementation of antibacterial treatment becomes delayed. The work presents the initial results of rapid microbiological identification based on an original method of capillary zone electrophoresis (CZE. The study involved the analysis of 78 biological samples from post-operative wounds and trophic ulcers. Results The attempt was made to identify individual bacterial species based on characteristic features of electropherograms achieved. Finally, G(+ cocci type bacteria and different G(- rods were identified with sensitivity of 88.1% and specificity of 100%. Conclusions Based on the clinical trials using an electrophoretic technique in the field of microbiological diagnostics of infected exudate from a post-operative wound it can be concluded that it is a rapid and relatively sensitive method for initial identification of infectious pathogens.

  18. Tris(2,2'-bipyridyl) ruthenium(II)-bisoprolol-based electrochemiluminescence coupled with capillary zone electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jingwu [Department of Chemistry, Nanchang University, Nanchang 330031 (China)], E-mail:; Zhang Xiaojun; Pi Fangfang [Department of Chemistry, Nanchang University, Nanchang 330031 (China); Wang Xiaoxia [Graduate School of Engineering, University of Fukui, Fukui 910-8507 (Japan); Yang Nianjun [Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Central 2-13, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)], E-mail:


    Capillary zone electrophoresis (CZE) coupled with tris(2,2'-bipyridyl) ruthenium(II)-based end-column electrogenerated chemiluminescence (ECL) has been utilized to detect bisoprolol in drugs and tablets after its separation from metoprolol. Tetrahydrofuran was used as an additive in the running buffer to obtain the absolute ECL peak of bisoprolol. Bisoprolol reacts as a co-reactant in tris(2,2'-bipyridyl) ruthenium(II) ECL system. Under the optimized experimental conditions, bisoprolol was separated successfully and efficiently from metoprolol and other co-existed materials in tablets and urine samples. The ECL intensity of tris(2,2'-bipyridyl) ruthenium(II)-bisoprolol-based system is linear with the concentration of bisoprolol from 1.5 {mu}M to 0.3 mM with a detection limit of 0.3 {mu}M. Relative standard derivations of the ECL intensity are 2.58% for the detection of 15 {mu}M bisoprolol. This method is a simple, rapid, selective, and sensitive. It was applied successfully for the monitoring of bisoprolol in market available tablets and human urine samples.

  19. Determination of eight illegal drugs in human urine by combination of magnetic solid-phase extraction with capillary zone electrophoresis. (United States)

    Chen, Ming-Luan; Suo, Li-Li; Gao, Qiang; Feng, Yu-Qi


    Using magnetite/silica/poly(methacrylic acid-co-ethylene glycol dimethacrylate) (Fe(3)O(4)/SiO(2)/poly(MAA-co-EDMA)) magnetic microspheres, a rapid and high-throughput magnetic solid-phase extraction coupled with capillary zone electrophoresis (MSPE-CZE) method was developed for the determination of illegal drugs (ketamine, amphetamines, opiates, and metabolites). The MSPE of target analytes could be completed within 2 min, and the eight target analytes could be baseline separated within 15 min by CZE with 30 mM phosphate buffer solution (PBS, pH 2.0) containing 15% v/v ACN as background electrolyte. Furthermore, hydrodynamic injection with field-amplified sample stacking (FASS) was employed to enhance the sensitivity of this MSPE-CZE method. Under such optimal conditions, the limits of detection for the eight target analytes ranged from 0.015 to 0.105 μg/mL. The application feasibility of MSPE-CZE in illegal drugs monitoring was demonstrated by analyzing urine samples, and the recoveries of target drugs for the spiked sample ranging from 85.4 to 110.1%. The method reproducibility was tested by evaluating the intra- and interday precisions, and relative standard deviations of <10.3 and 12.4%, respectively, were obtained. To increase throughput of the analysis, a home-made MSPE array that has potential application to the treatment of 96 samples simultaneously was used.

  20. Comparison of chiral recognition capabilities of cyclodextrins for the separation of basic drugs in capillary zone electrophoresis. (United States)

    Jin, L J; Li, S F


    The enantiomeric separation of some racemic anti-histamines and anti-malarials, namely (+/-)-pheniramine, (+/-)-brompheniramine, (+/-)-chlorpheniramine, (+/-)-doxylamine, and (+/-)-chloroquine, was investigated by capillary zone electrophoresis. The enantiomeric separation of five compounds was obtained by addition of approximately 7 mM (1%, w/v) sulfated-beta-cyclodextrin into the buffer as a chiral selector. The effects of sulfated-beta-cyclodextrin concentration and buffer pH on migration and resolution are discussed. Two other cyclodextrins, carboxyethylated-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin were also investigated. Four of the racemic compounds were resolved using 14 mM (2%, w/v) carboxyethylated-beta-cyclodextrin while 28 mM (4%, w/v) hydroxypropyl-beta-cyclodextrin resolved only two of them. It was found that the type of substituent and the degree of substitution on the rim of the CD structure played an important role in enhancing the chiral recognition. Cyclodextrins with negatively charged substituents and higher degree of substitution on the rim of the structure proved to give better resolution to the cationic racemic compounds compared with cyclodextrin with neutral substituents. This is due to the countercurrent mobility of the negatively charged cyclodextrin relative to the cationic analytes thus allowing for a smaller difference in interaction constants to achieve a successful resolution of enantiomers. Furthermore, lower concentrations of negatively charged cyclodextrins were necessary to achieve the equivalent resolutions as compared with the neutral ones.

  1. Separation and analysis of triazine herbcide residues by capillary electrophoresis. (United States)

    Elbashir, Abdalla A; Aboul-Enein, Hassan Y


    Triazines are widely used in agriculture around the world as selective pre- and post-emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized.

  2. Copolymers For Capillary Gel Electrophoresis (United States)

    Liu, Changsheng; Li, Qingbo


    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  3. Multidimensional capillary electrophoresis. (United States)

    Grochocki, Wojciech; Markuszewski, Michał J; Quirino, Joselito P


    Multidimensional separation where two or more orthogonal displacement mechanisms are combined is a promising approach to increase peak capacity in CE. The combinations allow dramatic improvement of analytical performance since the total peak capacity is given by a product of the peak capacities of all methods. The initial reports were concentrated on the construction of effective connections between capillaries for 2D analysis. Today, 2D and 3D CE systems are now able to separate real complex biological or environmental mixtures with good repeatability, improved resolution with minimal loss of sample. This review will present the developments in the field of multidimensional CE during the last 15 years. The endeavors in this specific field were on the development of interfaces, interface-free techniques including integrated separations, microdevices, and on-line sample concentration techniques to improve detection sensitivity.

  4. Comparison of hydrodynamically closed isotachophoresis-capillary zone electrophoresis with hydrodynamically open capillary zone electrophoresis hyphenated with tandem mass spectrometry in drug analysis: pheniramine, its metabolite and phenylephrine in human urine. (United States)

    Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Mikuš, Peter


    The advanced two dimensional isotachophoresis (ITP)-capillary zone electrophoresis (CZE) hyphenated with tandem mass spectrometry (MS/MS, here triple quadrupole, QqQ) was developed in this work to demonstrate analytical potentialities of this approach in the analysis of drugs in multicomponent ionic matrices. Pheniramine (PHM), phenylephrine (PHE), paracetamol (PCM) and their potential metabolic products were taken for the analysis by the ITP-CZE-ESI-QqQ technique working in hydrodynamically closed CE separation system and then a comparison with the conventional (hydrodynamically open) CZE-ESI-QqQ technique was made. The ITP-CZE-ESI-QqQ method was favorable in terms of obtainable selectivity (due to highly effective heart-cut analysis), concentration limits of detection (LOD at pgmL(-1) levels due to enhanced sample load capacity and ITP preconcentration), sample handling (on-line sample pretreatment, i.e. clean-up, preconcentration, preseparation), and, by that, possibilities for future automation and miniaturization. On the other hand, this experimental arrangement, in contrast to the CZE-ESI-QqQ arrangement supported by an electroosmotic flow, is principally limited to the analysis of uniformly (i.e. positively or negatively) charged analytes in one run without any possibilities to analyze neutral compounds (here, PCM and neutral or acidic metabolites of the drugs had to be excluded from the analysis). Hence, these general characteristics should be considered when choosing a proper analytical CE-MS approach for a given biomedical application. Here, the analytical potential of the ITP-CZE-ESI-QqQ method was demonstrated showing the real time profiles of excreted targeted drugs and metabolite (PHM, PHE, M-PHM) in human urine after the administration of one dose of Theraflu(®) to the volunteers.

  5. Capillary electrophoresis systems and methods (United States)

    Dorairaj, Rathissh; Keynton, Robert S.; Roussel, Thomas J.; Crain, Mark M.; Jackson, Douglas J.; Walsh, Kevin M.; Naber, John F.; Baldwin, Richard P.; Franco, Danielle B.


    An embodiment of the invention is directed to a capillary electrophoresis apparatus comprising a plurality of separation micro-channels. A sample loading channel communicates with each of the plurality of separation channels. A driver circuit comprising a plurality of electrodes is configured to induce an electric field across each of the plurality of separation channels sufficient to cause analytes in the samples to migrate along each of the channels. The system further comprises a plurality of detectors configured to detect the analytes.

  6. Capillary electrophoresis in food authenticity. (United States)

    Kvasnicka, Frantisek


    Food authenticity is a term which simply refers to whether the food purchased by the consumer matches its description. False description can occur in many forms, from the undeclared addition of water or other cheaper materials, or the wrong declaration of the amount of a particular ingredient in the product, to making false statements about the source of ingredients i.e., their geographic, plant, or animal origin. The aim of this review is to summarize applications of capillary electrophoresis in food authentication.

  7. Capillary Electrophoresis - Optical Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M. J.


    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  8. Non-Aqueous Capillary Electrophoresis (United States)

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  9. DNA Sequencing Using capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Barry Karger


    The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

  10. Lipid Characterization of White, Dark, and Milk Chocolates by FT-Raman Spectroscopy and Capillary Zone Electrophoresis. (United States)

    de Oliveira, Leandra Natália; de Jesus Coelho Castro, Renata; de Oliveira, Marcone Augusto Leal; de Oliveira, Luiz Fernando C


    There are few studies about different types of chocolate and their chemical characterization by Fourier transform (FT)-Raman spectroscopy and capillary zone electrophoresis (CZE). The aim of this study was to evaluate the lipid profile of different types of Brazilian chocolate through characterization by FT-Raman spectroscopy and identification and quantification of major fatty acids (FAs) by CZE to confirm FT-Raman spectrometry results. It was found that the main spectroscopic profile difference of the chocolate samples analyzed was related to the presence of saturated or unsaturated FAs. Well defined bands at approximately 1660, 1267, and 1274 cm(-1) corresponding to vibrational modes of unsaturated FAs (UnFAs) were found only in the spectra of samples with cocoa butter in their composition according to label specifications, mainly in dark chocolate samples. The FA identification and quantification by CZE found the presence of stearic (18:0) and palmitic (16:0) acids as the major saturated FAs in all chocolate samples. Dark chocolate samples showed the highest levels of oleic (cis-9 18:1) and linoleic (cis, cis -9,12 18:2) UnFAs monitored and the lowest levels of 14:0 in their chemical composition. Samples coded as 02 (with not only cocoa butter in their composition according to label) had the highest levels of 14:0 (FA not present in cocoa butter composition) corresponding to label information and inferring the presence of other fat sources, called cocoa butter substitutes, mainly for milk and white chocolate samples. This study suggests FT-Raman spectroscopy is a powerful technique that can be used to chemically characterize the chocolate lipid fraction, and CZE is a tool able to confirm Raman spectroscopy results and identify and quantify the major FAs in chocolate samples.

  11. Polymerized phospholipid bilayers as permanent coatings for small amine separations using mixed aqueous/organic capillary zone electrophoresis. (United States)

    Pei, Lei; Lucy, Charles A


    Phospholipid bilayer (SPB) coatings have been used in capillary electrophoresis to reduce the nonspecific adsorption between the capillary wall and cationic analytes. This paper describes the use of the polymerizable lipid 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (Diyne PC) as a permanent capillary coating. A supported phospholipid bilayer was formed on the capillary walls and polymerization was performed in situ using ultraviolet irradiation. The polymerization reaction was monitored by UV-visible absorbance spectroscopy and atomic force microscopy. The EOF of the polymerized Diyne PC coating was moderately suppressed (2.0×10(-4)cm(2)/Vs) compared to a non-polymerized Diyne PC bilayer (0.3×10(-4)cm(2)/Vs), but the stability was improved significantly. Separations of benzylamine, veratrylamine, phenylethylamine and tolyethylamine using a poly Diyne PC coated capillary yielded efficiency of 220,000-370,000 plates/m and peak asymmetry factor 0.48-1.18. Specifically, the poly(Diyne PC) coating provided improved separation resolution in NACE due to the reduced surface adsorption.

  12. Capillary electrophoresis theory and practice

    CERN Document Server

    Grossman, Paul D


    This book is designed to be a practical guide, used by wide audience, including those new to CE, those more experienced, routine users, those interested in technology development, and those involved with applications research. References have been emphasized to allow the reader to explore the detailed specifics and theoretical foundations.This book draws together the rapidly evolving, diverse, and multidisciplinary subject of capillary electrophoresis (CE). It is designed as a practical guide to be used by a wide audience, including those new to CE as well as more experienced users. T

  13. Electromigration dispersion in Capillary Electrophoresis

    CERN Document Server

    Chen, Zhen; 10.1007/s11538-011-9708-7


    In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010, vol. 72, pg. 2047) it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data.

  14. Simultaneous determination of six toxic alkaloids in human plasma and urine using capillary zone electrophoresis coupled to time-of-flight mass spectrometry. (United States)

    Yu, Zhuhong; Wu, Zhongping; Gong, Feijun; Wong, Rong; Liang, Chen; Zhang, Yurong; Yu, Yunqiu


    A novel capillary zone electrophoresis separation coupled to electro spray ionization time-of-flight mass spectrometry method was developed for the simultaneous analysis of six toxic alkaloids: brucine, strychnine, atropine sulfate, anisodamine hydrobromide, scopolamine hydrobromide and anisodine hydrobromide in human plasma and urine. To obtain optimal sensitivity, a solid-phase extraction method using Oasis MCX cartridges (1 mL, 30 mg; Waters, USA) for the pretreatment of samples was used. All compounds were separated by capillary zone electrophoresis at 25 kV within 12 min in an uncoated fused-silica capillary of 75 μm id × 100 cm and were detected by time-of-flight mass spectrometry. This method was validated with regard to precision, accuracy, sensitivity, linear range, limit of detection (LOD), and limit of quantification (LOQ). In the plasma and urine samples, the linear calibration curves were obtained over the range of 0.50-100 ng/mL. The LOD and LOQ were 0.2-0.5 ng/mL and 0.5-1.0 ng/mL, respectively. The intra- and interday precision was better than 12% and 13%, respectively. Electrophoretic peaks could be identified by mass analysis.

  15. One step physically adsorbed coating of silica capillary with excellent stability for the separation of basic proteins by capillary zone electrophoresis. (United States)

    Guo, Xiao-Feng; Guo, Xiao-Mei; Wang, Hong; Zhang, Hua-Shan


    The coating of capillary inner surface is considered to be an effective approach to suppress the adsorption of proteins on capillary inner surface in CE. However, most of coating materials reported are water-soluble, which may dissolve in BGE during the procedure of electrophoresis. In this study, a novel strategy for selection of physically coating materials has been illustrated to get coating layer with excellent stability using materials having poor solubility in commonly used solvents. Taking natural chitin as example (not hydrolyzed water soluble chitosan), a simple one step coating method using chitin solution in hexafluoroisopropanol was adopted within only 21 min with good coating reproducibility (RSDs of EOF for within-batch coated capillaries of 1.55% and between-batch coated capillaries of 2.31%), and a separation of four basic proteins on a chitin coated capillary was performed to evaluate the coating efficacy. Using chitin coating, the adsorption of proteins on capillary inner surface was successfully suppressed with reversed and stable EOF, and four basic proteins including lysozyme, cytochrome c, ribonuclease A and α-chymotrypsinogen A were baseline separated within 16 min with satisfied separation efficiency using 20 mM pH 2.0 H3PO4-Na2HPO4 as back ground electrolyte and 20 kV as separation voltage. What is more important, the chitin coating layer could be stable for more than two months during this study, which demonstrates that chitin is an ideal material for preparing semi-permanent coating on bare fused silica capillary inner wall and has hopeful potential in routine separation of proteins with CE.

  16. DNA Sequencing Using capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Barry Karger


    The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

  17. αS1-casein in goat milk: identification of genetic variants by Capillary Zone Electrophoresis compared to Isoelectric Focusing

    Directory of Open Access Journals (Sweden)

    G. Enne


    Full Text Available AlphaS1 casein fraction in caprine milk is characterized by an important polymorphism due to substitution, deletion of amino acids and post trascriptional modifications (Grosclaude et al., 1994; Ferranti et al., 1997. This structural polymorphism is associated to a quantitative variability in protein expression related to different milk quality and dairy properties (Pierre et al., 1998; Remeuf, 1993; Vassal et al., 1994. Classical electrophoretic methods were applied to characterize the phenotypic variants at αS1-casein fraction (Addeo et al., 1988; Russo et al., 1986. During the last ten years capillary electrophoresis became an analytical technique for rapid and automated analysis requiring small sample volume and small solvent waste. These characteristics, together with the high resolution and the chance to give quantitative results, made this technique a useful tool........

  18. Comparison of methanol and acetonitrile as solvents for the separation of sertindole and its major metabolites by capillary zone electrophoresis. (United States)

    Subirats, Xavier; Reinstadler, Sigrun; Porras, Simo P; Raggi, Maria Augusta; Kenndler, Ernst


    Sertindole (1-[2-[4-[5-chloro-1-(4-fluorophenyl)-1H-indol-3-yl]-1-piperidinyl]ethyl]-2-imidazolidinone), an atypical antipsychotic drug, was separated by capillary electrophoresis from its two main metabolites norsertindole and dehydrosertindole. The low solubility of the analytes in water (octanol-water partition coefficient is about 10(5)) is overcome by the use of methanol (MeOH) and acetonitrile (ACN) as solvents for the background electrolyte (BGE). Mobilities were measured in BGEs with defined pH in a broad range. It was found that in MeOH the mobility of the analytes is mainly governed by acid-base equilibria, whereas in ACN other reactions like ion pairing and homo-conjugation play a pronounced role and lead to a complex pattern of the mobility as function of the pH. However, separation can be obtained in less than 10 min in both solvent systems.

  19. Design of experiments for amino acid extraction from tobacco leaves and their subsequent determination by capillary zone electrophoresis. (United States)

    Hodek, Ondřej; Křížek, Tomáš; Coufal, Pavel; Ryšlavá, Helena


    In this study, we optimized a method for the determination of free amino acids in Nicotiana tabacum leaves. Capillary electrophoresis with contactless conductivity detector was used for the separation of 20 proteinogenic amino acids in acidic background electrolyte. Subsequently, the conditions of extraction with HCl were optimized for the highest extraction yield of the amino acids because sample treatment of plant materials brings some specific challenges. Central composite face-centered design with fractional factorial design was used in order to evaluate the significance of selected factors (HCl volume, HCl concentration, sonication, shaking) on the extraction process. In addition, the composite design helped us to find the optimal values for each factor using the response surface method. The limits of detection and limits of quantification for the 20 proteinogenic amino acids were found to be in the order of 10(-5) and 10(-4) mol l(-1), respectively. Addition of acetonitrile to the sample was tested as a method commonly used to decrease limits of detection. Ambiguous results of this experiment pointed out some features of plant extract samples, which often required specific approaches. Suitability of the method for metabolomic studies was tested by analysis of a real sample, in which all amino acids, except for L-methionine and L-cysteine, were successfully detected. The optimized extraction process together with the capillary electrophoresis method can be used for the determination of proteinogenic amino acids in plant materials. The resulting inexpensive, simple, and robust method is well suited for various metabolomic studies in plants. As such, the method represents a valuable tool for research and practical application in the fields of biology, biochemistry, and agriculture.

  20. Atomic Force Controlled Capillary Electrophoresis (United States)

    Lewis, Aaron; Yeshua, Talia; Palchan, Mila; Lovsky, Yulia; Taha, Hesham


    Lithography based on scanning probe microscopic techniques has considerable potential for accurate & localized deposition of material on the nanometer scale. Controlled deposition of metallic features with high purity and spatial accuracy is of great interest for circuit edit applications in the semiconductor industry, for plasmonics & nanophotonics and for basic research in surface enhanced Raman scattering & nanobiophysics. Within the context of metal deposition we will review the development of fountain pen nanochemistry and its most recent emulation Atomic Force Controlled Capillary Electrophoresis (ACCE). Using this latter development we will demonstrate achievement of unprecedented control of nanoparticle deposition using a three-electrode geometry. Three electrodes are attached: one on the outside of a metal coated glass probe, one on the inside of a hollow probe in a solution containing Au nanoparticles in the capillary, and a third on the surface where the writing takes place. The three electrodes provide electrical pulses for accurate control of deposition and retraction of the liquid from the surface overcoming the lack of control seen in both dip pen lithography & fountain pen nanochemistry when the tip contacts the surface. With this development, we demonstrate depositing a single 1.3 nm Au nanoparticle onto surfaces such as semiconductors.

  1. 20 Years of Fatty Acid Analysis by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Marcone Augusto Leal de Oliveira


    Full Text Available A review taking into account the literature reports covering 20 years of fatty acid analysis by capillary electrophoresis is presented. This paper describes the evolution of fatty acid analysis using different CE modes such as capillary zone electrophoresis, non-aqueous capillary electrophoresis, micellar electrokinetic capillary chromatography and microemulsion electrokinetic chromatography employing different detection systems, such as ultraviolet-visible, capacitively coupled contactless conductivity, laser-induced fluorescence and mass spectrometry. In summary, the present review signals that CE seems to be an interesting analytical separation technique that is very useful for screening analysis or quantification of the usual fatty acids present in different matrices, offering short analysis times and a simple sample preparation step as inherent advantages in comparison with the classical methodology, making it a separation technique that is very attractive for quality control in industry and government agencies.

  2. Simultaneous determination of the beta-blocker atenolol and several complementary antihypertensive agents in pharmaceutical formulations and urine by capillary zone electrophoresis. (United States)

    Maguregui, M I; Jiménez, R M; Alonso, R M


    A simple capillary zone electrophoresis method is developed for the quantitation of the beta-blocker atenolol and the complementary antihypertensive agents bendroflumethiazide, amiloride, and hydrochlorothiazide in human urine samples. The electrophoretic separation is performed using a 78-cm x 75-micron-i.d. (70-cm effective length) fused-silica capillary. A borate buffer (pH 9) is used as running electrolyte. The sample is hydrostatically introduced for 20 s, and the running voltage is 25 kV at the injector end of the capillary. The analysis of urine samples requires the optimization of solid-phase extraction methods, achieving recoveries > or = 61% for all the drugs and good separation from the urine matrix. The method is successfully applied to the determination of these compounds in pharmaceutical formulations and in urine samples collected after the intake of Neatenol Diu (100 mg atenolol-5 mg bendroflumethiazide) and Kalten (50 mg atenolol-25 mg hydrochlorothiazide-2.5 mg amiloride). The method is validated in terms of reproducibility, linearity, and accuracy.

  3. A New Conductivity Detector for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    A new conductivity detector for capillary electrophoresis consisting of an electrochemical cell and a conductive meter was developed. In the cell, the microelectrode and capillary were inserted through the cell wall and fixed by screws and sealing ring, the ends of microelectrode and capillary were located by a guide with two cross holes. LOD for K+ was 1.5×10-5 mol/L.

  4. Analysis of phenolic compounds in Spanish Albrariño and Portuguese Alvarinho and Loureiro wines by capillary zone electrophoresis and high-performance liquid chromatography. (United States)

    Andrade, P B; Oliveira, B M; Seabra, R M; Ferreira, M A; Ferreres, F; García-Viguera, C


    The concentration of different phenolic compounds was measured in Spanish Albariño and Portuguese Alvarinho and Loureiro white wines by capillary zone electrophoresis (CZE), in order to characterize them. Although all samples presented the same qualitative pattern (characterized by tyrosol; (-)-epicatechin; syringic acid; ferulic acid; p-coumaric acid; caffeic acid, gallic acid; 3,4-dihydroxybenzoic acid; cis-coumaroyl tartaric acid (COUTA); trans-COUTA; trans-caffeoyl tartaric acid (CAFTA), and hydroxycinnamic esters), some quantitative differences were observed. When samples were analyzed by high-performance liquid chromatography (HPLC), in order to compare the results obtained by both techniques, no significant qualitative or quantitative differences were obtained. Nevertheless, CZE proved to be a more convenient technique for the routinary analyses of these wines, due to better separation of the different compounds, better peak shapes, and higher speed than HPLC.

  5. Characterization of fruit products by capillary zone electrophoresis and liquid chromatography using the compositional profiles of polyphenols: application to authentication of natural extracts. (United States)

    Navarro, Meritxell; Núñez, Oscar; Saurina, Javier; Hernández-Cassou, Santiago; Puignou, Lluis


    Capillary zone electrophoresis (CZE) and high performance liquid chromatography (HPLC) were applied to the authentication of fruit products based on the compositional profiles of polyphenols. Various sample treatments were used to maximize the overall recovery of polyphenols or specific fractions, such as phenolic acids or anthocyanins. The resulting CZE and HPLC data were treated with Principal Component Analysis (PCA) showing that samples were mainly clustered according to the fruit of origin, with cranberry- and grape-based products clearly separated in groups. A possible adulterated cranberry extract was analyzed more deeply by high resolution mass spectrometry (HRMS) in order to identify the presence of A-type proanthocyanidins, which are characteristic and more abundant in cranberry-based products. In accordance with PCA interpretation, HRMS results indicated that the suspicious sample was not a cranberry-based product, allowing us to validate and demonstrate the suitability of both CZE- and HPLC-proposed methods for the characterization of fruit-based products.

  6. Simultaneous determination of histamine and polyamines by capillary zone electrophoresis with 4-fluor-7-nitro-2,1,3-benzoxadiazole derivatization and fluorescence detection. (United States)

    Zhang, Li-Yao; Tang, Xing-Chun; Sun, Meng-Xiang


    Capillary zone electrophoresis (CZE) with fluorescence detection was applied to the simultaneous determination of histamine and polyamines including spermine, spermidine, diaminopropane, putrescine, cadaverine, diaminohexane with 4-fluor-7-nitro-2,1,3-benzoxadiazole (NBD-F) as the fluorescent derivatization reagent. The seven NBD-F labeled amines was separated within 200 s using 85 mM phosphate running buffer at pH 3.0. The concentration limits of these amines ranged from 5.1 x 10(-8) M for spermine to 2.1 x 10(-8) M for histamine. The relative standard deviations for migration time and peak height were less than 1.5% and 6.0%, respectively. The method was successfully applied to the analysis of biogenic amines in the lysate of tobacco mesophyll protoplasts, and spermidine and putrescine were detected in the lysate with satisfying recovery.

  7. Capillary Electrophoresis in the Analysis of Polyunsaturated Fatty Acids

    Directory of Open Access Journals (Sweden)

    Gabriel Hancu


    Full Text Available The aim of this study to inventory the main electrophoretic methods for identification and quantitative determination of fatty acids from different biological matrices. Critical analysis of electrophoretic methods reported in the literature show that the determination of polyunsaturated fatty acids can be made by: capillary zone electrophoresis, micellar electrokinetic chromatography and microemulsion electrokinetic chromatography using different detection systems such as ultraviolet diode array detection, laser induced fluorescence or mass – spectrometry. Capillary electrophoresis is a fast, low-cost technique used for polyunsaturated fatty acids analysis although their determination is mostly based on gas chromatography.

  8. Development and optimization of a capillary zone electrophoresis technique for simultaneous determination of miconazole nitrate and hydrocortisone acetate in a cream pharmaceutical formulation. (United States)

    Korany, Mohamed A; Maher, Hadir M; Galal, Shereen M; Ragab, Marwa A A


    A simple, fast, inexpensive, and reliable capillary zone electrophoresis (CZE) method for the determination of a mixture of miconazole nitrate (MCZ) and hydrocortisone acetate (HCZ) in a cream formulation has been developed and validated. Optimum conditions were sodium dihydrogen phosphate buffer (50 mM, pH 4) and 30 kV applied voltage in a 85 cm x 75 pm id capillary. Direct UV detection at 230 nm led to adequate sensitivity without interference from the sample excipients. MCZ and HCZ migrated in approximately 165 and 415 s, respectively. The analytical curves had a coefficient of correlation, r, of 0.9999 and 0.9996 for MCZ and HCZ, respectively. The LOD and LOQ were 0.28 and 0.93 microg/mL for MCZ and 0.38 and 1.27 microg/mL for HCZ, respectively. Thus, excellent accuracy and precision were obtained. Recoveries varied from 98 to 102%, and intraday and interday precision, calculated as the RSD, were less than 2.0% for each drug. The proposed CZE method displayed advantageous performance characteristics and can be considered suitable for QC of the MCZ and HCZ cream formulation.

  9. On-Line Organic Solvent Field Enhanced Sample Injection in Capillary Zone Electrophoresis for Analysis of Quetiapine in Beagle Dog Plasma. (United States)

    Cao, Yuqing; Wen, Jun; Zhou, Tingting; Fan, Guorong


    A rapid and sensitive capillary zone electrophoresis (CZE) method with field enhanced sample injection (FESI) was developed and validated for the determination of quetiapine fumarate in beagle dog plasma, with a sample pretreatment by LLE in 96-well deep format plate. The optimum separation was carried out in an uncoated 31.2 cm × 75 μm fused-silica capillary with an applied voltage of 13 kV. The electrophoretic analysis was performed by 50 mM phosphate at pH 2.5. The detection wavelength was 210 nm. Under these optimized conditions, FESI with acetonitrile enhanced the sensitivity of quetiapine about 40-50 folds in total. The method was suitably validated with respect to stability, specificity, linearity, lower limit of quantitation, accuracy, precision and extraction recovery. Using mirtazapine as an internal standard (100 ng/mL), the response of quetiapine was linear over the range of 1-1000 ng/mL. The lower limit of quantification was 1 ng/mL. The intra- and inter-day precisions for the assay were within 4.8% and 12.7%, respectively. The method represents the first application of FESI-CZE to the analysis of quetiapine fumarate in beagle dog plasma after oral administration.

  10. Determination of marbofloxacin by high performance capillary zone electrophoresis%高效毛细管电泳法用于麻保沙星的测定

    Institute of Scientific and Technical Information of China (English)

    李志伟; 崔哲; 刘波; 赵云超


    建立了一种高效毛细管电泳法测定麻保沙星原料药含量的方法.采用未涂层石英毛细管柱,以15 mmol/L硼酸钠缓冲液(pH值为9.2)为电泳介质,分离电压为20 kV,采用高度差进样10s,检测波长为295 nm,麻保沙星在10~100μg/mL范围内线性良好,平均回收率为100.2%,RSD值为0.97%.%A high performance capillary zone electrophoresis method was established for the determination of marbofloxacin drug substance. An untreated fused-silica capillary was used with 15 mmol/L sodium borate buffer (pH 9.2) as running buffer at the detection wavelength of 295 nm, separation voltage of 20 kV and the injection volume of sample for 10 s. The calibration curve for marbofloxacin is linear in the concentration range of 10 ~ 100 μg/mL. The average recovery is 100. 2% with RSD of 0.97%.

  11. Sub-minute method for simultaneous determination of aspartame, cyclamate, acesulfame-K and saccharin in food and pharmaceutical samples by capillary zone electrophoresis. (United States)

    Vistuba, Jacqueline Pereira; Dolzan, Maressa Danielli; Vitali, Luciano; de Oliveira, Marcone Augusto Leal; Micke, Gustavo Amadeu


    This paper reports the development of a sub-minute separation method by capillary zone electrophoresis for the determination of aspartame, cyclamate, acesulfame-K and saccharin in food products and pharmaceutical samples. Separations were performed in a fused uncoated silica capillary with UV detection at 220nm. Samples and standards were injected hydrodynamically using the short-end injection procedure. The electrophoretic system was operated under constant voltage of -30kV. The background electrolyte was composed of 45mmolL(-1) 2-amino-2-(hydroxymethyl)-1,3-propanediol and 15mmolL(-1) benzoic acid at pH 8.4. The separation time for all analytes was less than 1min. Evaluation of analytical parameters of the method showed good linearity (r(2)>0.9972), limit of detection of 3.3-6.4mgL(-1), intermediate precision better than 9.75% (peak area of sample) and recovery in the range of 91-117%.

  12. On-Line Organic Solvent Field Enhanced Sample Injection in Capillary Zone Electrophoresis for Analysis of Quetiapine in Beagle Dog Plasma

    Directory of Open Access Journals (Sweden)

    Yuqing Cao


    Full Text Available A rapid and sensitive capillary zone electrophoresis (CZE method with field enhanced sample injection (FESI was developed and validated for the determination of quetiapine fumarate in beagle dog plasma, with a sample pretreatment by LLE in 96-well deep format plate. The optimum separation was carried out in an uncoated 31.2 cm × 75 μm fused-silica capillary with an applied voltage of 13 kV. The electrophoretic analysis was performed by 50 mM phosphate at pH 2.5. The detection wavelength was 210 nm. Under these optimized conditions, FESI with acetonitrile enhanced the sensitivity of quetiapine about 40–50 folds in total. The method was suitably validated with respect to stability, specificity, linearity, lower limit of quantitation, accuracy, precision and extraction recovery. Using mirtazapine as an internal standard (100 ng/mL, the response of quetiapine was linear over the range of 1–1000 ng/mL. The lower limit of quantification was 1 ng/mL. The intra- and inter-day precisions for the assay were within 4.8% and 12.7%, respectively. The method represents the first application of FESI-CZE to the analysis of quetiapine fumarate in beagle dog plasma after oral administration.

  13. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng


    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows

  14. Mecanismos de Separação em Eletroforese Capilar Separation Mechanisms in Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Marina F. M. Tavares


    Full Text Available Since its inception in the 80's, capillary electrophoresis has matured into a well established technique for the separation and analysis of complex samples. One of its strongest aspects is the ability to handle materials from a diversity of chemical classes, ranging from few to millions of Daltons. This is only possible because several modes of electrophoresis can be performed in a single capillary format. In this work, relevant aspects of capillary zone electrophoresis in its three modes (free solution, micellar and gel, capillary isoelectric focusing and capillary isotachophoresis are discussed and many representative applications are presented.

  15. Instrumental development of novel detection and separation methods for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Garner, T.


    After a general introduction, this thesis is divided into 3 parts: indirect fluorescence detection of sugars separated by capillary zone electrophoresis with visible laser excitation, absorption detection in capillary electrophoresis by fluorescence energy transfer, and increased selectivity for electrochromatography by dynamic ion exchange.

  16. Capillaries for use in a multiplexed capillary electrophoresis system (United States)

    Yeung, E.S.; Chang, H.T.; Fung, E.N.


    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  17. Capillary Electrophoresis Analysis of Conventional Splicing Assays

    DEFF Research Database (Denmark)

    de Garibay, Gorka Ruiz; Acedo, Alberto; García-Casado, Zaida;


    of these assays is often challenging. Here, we explore this issue by conducting splicing assays in 31 BRCA2 genetic variants. All variants were assessed by RT-PCR followed by capillary electrophoresis and direct sequencing. If assays did not produce clear-cut outputs (Class-2 or Class-5 according to analytical...

  18. Rapid quantitative analysis of phenazine-1-carboxylic acid and 2-hydroxyphenazine from fermentation culture of Pseudomonas chlororaphis GP72 by capillary zone electrophoresis. (United States)

    Liu, Hai-Ming; Zhang, Xue-Hong; Huang, Xian-Qing; Cao, Cheng-Xi; Xu, Yu-Quan


    Natural phenazines in secondary metabolites of bacteria have been receiving increasing attention in recent years due to their potential usage as antibiotics. In the present study, a rapid and reliable capillary zone electrophoresis (CZE) method was developed and validated for monitoring for the first time dynamic phenazine-1-carboxylic acid (PCA) and the 2-hydroxyphenazine (2-OH-PHZ) production of Pseudomonas chlororaphis GP72 during the entire fermentation cycle. The paper begins with the optimization of separate conditions for 2-OH-PHZ and PCA together with phenazine (PHZ), which is used as internal standard. The optimized conditions are: 10mM, pH 7.3 phosphate buffer, a fused-silica capillary with a total length of 49 cm x 75 microm ID, 375 microm OD with an effective length of 40 cm, 25 kV, 13 mbar 10s pressure sample injection and 25 degrees C air-cooling. The three compounds could be separated within 2 min under optimized conditions. The validation of the newly developed study shows the linear response of 2-OH-PHZ and PCA ranging from 10 to 250 microg mL(-1) with high correlation coefficient (r=0.9997 and 0.9993, n=7), low limits of detection (0.47 and 0.38 microg mL(-1)) and quantification (1.56 and 1.28 microg mL(-1)), respectively. Good precision values for intra- and inter-day detection and acceptable individual recovery ranges for 2-OH-PHZ and PCA are indicated. The newly developed method was also validated through monitoring dynamic PCA and 2-OH-PHZ production of P. chlororaphis GP72 during an 84 h growth cycle.

  19. Stability-indicating capillary zone electrophoresis method for the assessment of recombinant human interleukin-11 and its correlation with reversed-phase liquid chromatography and biossay. (United States)

    Souto, Ricardo Bizogne; Stamm, Fernanda Pavani; Schumacher, Jéssica Barbieri; Cardoso, Clovis Dervil Appratto; de Freitas, Guilherme Weber; Perobelli, Rafaela Ferreira; Dalmora, Sérgio Luiz


    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of recombinant human interleukin-11(rhIL-11) using rupatadine fumarate, as internal standard (IS). A fused-silica capillary, (50 µm i.d.; effective length, 40 cm) was used at 25°C; the applied voltage was 20 kV. The background electrolyte solution consisted of 50 mmol L(-1) sodium dihydrogen phosphate solution at pH 3.0. Injections were performed using a pressure mode at 50 mbar for 45 s, with detection by photodiode array detector set at 196 nm. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The method was linear over the concentration range of 1.0-300 µg mL(-1) (r(2)=0.9992) and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.2 µg mL(-1) and 1.0 µg mL(-1), respectively. The accuracy was 100.4% with bias lower than 1.1%. Moreover, the in vitro cytotoxicity test of the degraded products showed significant differences (pmethod was applied for the content/potency assessment of rhIL-11 in biopharmaceutical formulations, and the results were correlated to those of a validated reversed-phase LC method (RP-LC) and an TF-1 cell culture assay, showing non-significant differences (p>0.05). In addition the CZE and RP-LC methods were applied for the analysis of rhIL-11 in human plasma. Therefore, the proposed alternative method can be applied to monitor stability, to assure the batch-to-batch consistency and quality of the bulk and finished biotechnology-derived medicine.

  20. Optimisation for the separation of the oligosaccharide, sodium Pentosan Polysulfate by reverse polarity capillary zone electrophoresis using a central composite design. (United States)

    Prochazka, S; Mulholland, M; Lloyd-Jones, A


    The separation by reverse polarity capillary zone electrophoresis of the therapeutically developed sodium salt of Pentosan Polysulfate was optimised through the analysis of response surface methodologies, modeled using a central composite design. The optimisation investigated injection pressure, injection time and voltage and the effect of the conditions on retention times, peak areas, separation efficiency and the method sensitivity. The overall goal was to develop the most sensitive results with no decrease in separation efficiency. The following results were obtained: (1) retention times generally decreased as injection pressure, injection time and voltage increased, injection time having the least effect; (2) as expected peak areas increased as injection pressure and injection time increased but decreased as voltage increased; (3) separation efficiencies generally increased as injection pressure and injection time decreased, with voltage having almost no effect. For the optimum condition, the sample was introduced at the inlet vial at the cathode hydrodynamically, at optimal setting of 44 s at 35 mbar. The optimal voltage was -20 kV. In comparison with other methods, the optimum showed increased sensitivity, resolution and separation efficiency. Repeatability studies were performed on the optimum parameter conditions. Relative standard deviation values obtained were between 0.9 and 5.4%.

  1. Water-miscible cooling lubricants - determination of anorganic anions and carboxylic acids using capillary zone electrophoresis; Wassermischbare Kuehlschmierstoffe - Bestimmung von anorganischen Anionen und Carbonsaeuren mittels der Kapillarzonenelektrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, B.A. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Dengel, H.S. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Hohaus, E. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Maurer, W. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Riepe, W. [Fachbereich 13, Analytische Chemie, Universitaet-GH Paderborn (Germany)


    A procedure is presented which allows the quantitative determination for most of the essentiell inorganic anions besides several carbonic acids (oxalic-, citric-, malonic-, tartaric-, formic-, succinic- and adipinic acid) in concentrates and industrial application emulsions of watermiscible cooling lubricants either free of mineral oil or oleiferous. The method used is based on capillary zones electrophoresis (CZE) using indirect UV-detection. The quantification of these substances regarding a qualiy surveillance of lubricants for manufacturers and a control of possible toxicological infleunces in working places is easily performed in spite of the complex matrix of the lubricants. Only a simple dilution is necessary. Analytical chemcial parameters such as accuracy, precision and recovery rate for concentrates and emulsions in industrial use for 1995/96 reveal sufficient universal application of the presented method for general purpose analyzing cooling lubricants. (orig.) [Deutsch] Es wird ein Verfahren vorgestellt, mit dem in Konzentraten und Emulsionen von wassermischbaren mineraloelfreien und mineraloelhaltigen Kuehlschmierstoffen (KSS) neben den wesentlichen anorganischen Anionen (Thiosulfat, Bromid, Chlorid, Sulfat, Nitrit, Nitrat, Perchlorat, Chlorat, Phosphonat, Fluorid, Phosphat) Carbonsaeuren (Oxal-, Citronen-, Malon-, Wein-, Ameisen-, Bernstein- und Adipinsaeure) mit Hilfe der Kapillarzonenelektrophorese (CZE) und indirekter UV-Detektion quantitativ bestimmt werden koennen. Die Quantifizierung dieser Substanzen im Rahmen von Qualitaetssicherungs- und Arbeitsschutzmassnahmen in KSS ist trotz der komplexen Matrix der KSS ohne eine aufwendige Probenvorbereitung moeglich. Ein einfacher Verduennungsschritt der Proben genuegt. Die analytischen Verfahrenskenngroessen Richtigkeit, Praezision, Wiederfindung sowie die Untersuchungsergebnisse fuer KSS-Konzentrate einiger Hersteller aus den Produktionsjahren 1995/96 werden vorgestellt. (orig.)

  2. Determination of volatile and non-volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography. (United States)

    Ligor, Magdalena; Jarmalaviciene, Reda; Szumski, Michal; Maruska, Audrius; Buszewski, Boguslaw


    The aim of the investigations was to develop analytical methods for the determination of selected volatile and non-volatile organic compounds numbering among the final products of milk fermentation. The analyzed compounds were as follows: biacetyl and carboxylic acids (formic, acetic, citric, and lactic). The model yogurt was prepared under controlled conditions in our laboratory by addition of the selected bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) to the milk sample. The temperature, time, and stirring were controlled during the fermentation process. Factors considered in SPMPE-GC-FID method development included fiber exposure time, salt addition, temperature of extraction, and temperature of desorption. Various SPME fibers, for example with PDMS, CAR/PDMS, PA, and PDMS/DVB coatings, were tested to obtain the highest recovery of the investigated compounds extracted from yogurt samples. Based on these preliminary experiments, qualitative and quantitative analyses for the determination of biacetyl were performed by SPME-GC-FID. Moreover, a capillary zone electrophoresis method was developed for the determination of carboxylic acids in the yogurt samples. The buffer composition as well as deproteinization by acetonitrile were found to have a crucial effect on the analysis.

  3. Development and validation of a sub-minute capillary zone electrophoresis method for determination of nitrate and nitrite in baby foods. (United States)

    Della Betta, Fabiana; Vitali, Luciano; Fett, Roseane; Costa, Ana Carolina Oliveira


    This paper proposes an innovative sub-minute capillary zone electrophoresis method and a simple sample preparation procedure for simultaneous nitrate and nitrite determination. The novelty of the method is the simplicity of execution and the capacity to separate the analytes in less than 0.5 min. The BGE is composed of 10 mmol L(-1) perchloric acid and 40 mmol L(-1) β-alanine at pH 3.96. Thiocyanate was used as an internal standard. The method was validated following the Eurachem guidelines and applied to the analysis of 14 baby food samples. Of these samples, one had nitrate levels above that permitted by Brazilian legislation (250 mg kg(-1)) and for all samples the nitrite concentrations were under the limit of quantification. The good analytical performance verified for this method indicates that it is suitable for implementation in food laboratories for the routine determination of nitrate and nitrite as an alternative to the official method provided by the AOAC.

  4. Comparative binding of antitumor indazolium [trans-tetrachlorobis(1H-indazole)ruthenate(III)] to serum transport proteins assayed by capillary zone electrophoresis. (United States)

    Timerbaev, Andrei R; Rudnev, Alexander V; Semenova, Olga; Hartinger, Christian G; Keppler, Bernhard K


    The indazolium [trans-tetrachlorobis(1H-indazole)ruthenate(III)] coordination compound shows notable antiproliferative activity in different tumor models and has recently ended phase I clinical trials as a lead anticancer metallodrug candidate. Its approval could be greatly facilitated if more precise information was available on the rate and degree of the drug's transformation occurring upon interaction with serum transport proteins and on the stability of the adducts formed. With this objective, a new method has been developed for the determination of the protein-binding rate and association constants under simulated physiological conditions by capillary zone electrophoresis (CZE). These binding parameters were assessed by monitoring the time- and concentration-dependent changes in peak area responses of reaction components, constructing the corresponding binding curves, and conducting a mathematical analysis. Comparison of the apparent rate constants determined by CZE revealed that indazolium [trans-tetrachlorobis(1H-indazole)ruthenate(III)] binds to transferrin much faster than to albumin: k=39.5 x 10(-4) and 3.3 x 10(-4)s(-1), respectively. The corresponding association constants are indicative of moderate metal-protein coordination, with a somewhat higher affinity of the Ru complex toward albumin (9910 and 6460 M(-1), respectively). The results of our study confirm in a quantitative manner that, in real bloodstream circumstances, plasma albumin may serve as a reservoir and a natural carrier of the administered ruthenium drug and hence mediate its accumulation in tumors.

  5. Study of Competitive Chelating Reaction between Lanthanum and Tribromoarsenazo in the Medium of Weak Acid by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    胡涌刚; 周培疆; 邓延倬; 程介克


    Two kinds of metal chelates of rare earth elements reacted with tribrimoarsenazo formed under the condition of critic acid were observed by simultaneous technique of capillary electrophoresisphotothermal interference spectrometry. The tendency of the conversion between these chelates as functions of the mole ratio of the reagent and the metal, pH value and the elapsing time was investigated. Kinetic equation of competitive chelating reaction between the TBA-La (Ⅲ) and La (Ⅲ) -critic acid were established. It was found that the competitive chelating reaction follows secondorder kinetics, for this second-order reaction, k=5.55 L·mol-1·S-1.

  6. Cycloaliphatic epoxy resin coating for capillary electrophoresis. (United States)

    Shah, Roopa S; Wang, Qinggang; Lee, Milton L


    Coating the interior surface of a fused-silica capillary with a polymeric material has long been used in capillary electrophoresis (CE) to reduce or eliminate electroosmotic flow and suppress adsorption. A cycloaliphatic epoxide-based resin was bonded to silane treated capillaries and crosslinked with a curing agent. The epoxy resin coating significantly reduced electroosmotic flow over a pH range of 3-10. This coating was sufficiently hydrophilic to suppress protein adsorption. The epoxy resin coated capillary was used to separate several acidic and basic proteins and peptides. Separation efficiencies greater than 400,000 theoretical plates were achieved. The relative standard deviations in migration times for proteins were methods.

  7. Micro-injector for capillary electrophoresis. (United States)

    Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C


    A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 μm diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core.

  8. Ionic Liquid and HP-β-CD Modified Capillary Zone Electrophoresis to Separate Hyperoside, Luteolin and Chlorogenic Acid

    Institute of Scientific and Technical Information of China (English)

    Yue Ling WANG; Zhong Bo HU; Zhuo Bin YUAN


    Ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate, 1E-3MI-TFB) and HP-β-CD as modifier was added to the buffer to separate hyperoside, luteolin and chlorogenic acid.Experiments explored the effect of concentration of 1E-3MI-TFB and HP-β-CD on separation.The results indicated that 1.0 mmol/L HP-β-CD and 1‰ (v/v) 1E-3MI-TFB added to the buffer simultaneous y could achieve a good compromise of resolution and analysis time. Capillary experiments and UV spectra indicated that there was interaction between 1E-3MI-TFB and analytes.

  9. Monitoring Homovanillic Acid and Vanillylmandelic Acid in Human Urine by Capillary Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)


    A simple, rapid and low-cost method of separation and determination of homovanillic acid and vanillylmandelic acid in human urine was developed based on capillary zone electrophoresis / amperometric detection with high sensitivity and good resolution.

  10. Cobalt complexes as internal standards for capillary zone electrophoresis-mass spectrometry studies in biological inorganic chemistry. (United States)

    Holtkamp, Hannah U; Morrow, Stuart J; Kubanik, Mario; Hartinger, Christian G


    Run-by-run variations are very common in capillary electrophoretic (CE) separations and cause imprecision in both the migration times and the peak areas. This makes peak and kinetic trend identification difficult and error prone. With the aim to identify suitable standards for CE separations which are compatible with the common detectors UV, ESI-MS, and ICP-MS, the Co(III) complexes [Co(en)3]Cl3, [Co(acac)3] and K[Co(EDTA)] were evaluated as internal standards in the reaction of the anticancer drug cisplatin and guanosine 5'-monophosphate as an example of a classical biological inorganic chemistry experiment. These Co(III) chelate complexes were considered for their stability, accessibility, and the low detection limit for Co in ICP-MS. Furthermore, the Co(III) complexes are positively and negatively charged as well as neutral, allowing the detection in different areas of the electropherograms. The background electrolytes were chosen to cover a wide pH range. The compatibility to the separation conditions was dependent on the ligands attached to the Co(III) centers, with only the acetylacetonato (acac) complex being applicable in the pH range 2.8-9.0. Furthermore, because of being charge neutral, this compound could be used as an electroosmotic flow (EOF) marker. In general, employing Co complexes resulted in improved data sets, particularly with regard to the migration times and peak areas, which resulted, for example, in higher linear ranges for the quantification of cisplatin.

  11. Capillary Electrophoresis in the Presence of Fosfomycin

    Institute of Scientific and Technical Information of China (English)


    Fosfomyein, a sodim salt of cis-(3-methyloxiranyl) phosphonic acid, was used as electrolyte in binary methanol-water media for capillary electrophoresis. The variety of electroosmotic flow with pH*,methanol concentration and ionic strength was investigated. The migration behavior of nine bases was examined under various conditions, and the separation of thymine, cytosine, 5-flurouracil, 4,6-diamino-pyrimidine, purine was accomplished.

  12. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)


    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  13. In-line coupling of microextractions across polymer inclusion membranes to capillary zone electrophoresis for rapid determination of formate in blood samples. (United States)

    Pantůčková, Pavla; Kubáň, Pavel; Boček, Petr


    Polymer inclusion membranes (PIMs) have several important features, i.e., PIMs are dry and non-porous membranes, which can be prepared ahead of use and stored without noticeable deterioration in extraction performance. In this contribution, in-line coupling of microextractions across PIMs to a separation method for clinical purposes was demonstrated for the first time. Formate (the major metabolite in methanol poisoning) was determined in undiluted human serum and whole blood by capillary zone electrophoresis (CZE) with simultaneous capacitively coupled contactless conductivity detection (C(4)D) and UV-Vis detection. A purpose-made microextraction device with PIM was coupled to a commercial CZE instrument in order to ensure complete automation of the entire analytical procedure, i.e., of formate extraction, injection, CZE separation and quantification. PIMs for formate extractions consisted of 60% (w/w) cellulose triacetate as base polymer and 40% (w/w) Aliquat™ 336 as anion carrier. The method was characterized by good repeatability of peak areas (≤7.0%) and migration times (≤0.8%) and by good linearity of calibration curves (r(2) = 0.993-0.999). Limits of detection in various matrices ranged from 15 to 54 μM for C(4)D and from 200 to 635 μM for UV-Vis detection and were sufficiently low to clearly distinguish between endogenous and toxic levels of formate in healthy and methanol intoxicated individuals. In addition, PIMs proved that they may act as phase interfaces with excellent long-term stability since once prepared, they retained their extractions properties for, at least, two months of storage.

  14. Selective enrichment and ultrasensitive identification of trace peptides in proteome analysis using transient capillary isotachophoresis/zone electrophoresis coupled with nano-ESI-MS. (United States)

    An, Yanming; Cooper, Jonathan W; Balgley, Brian M; Lee, Cheng S


    Besides the complexity in protein samples of biological origin, probably the greatest challenge presently facing comprehensive proteome analysis is related to the large variation of protein relative abundances (>6 orders of magnitude), having potential biological significance in mammalian systems. As demonstrated in this work, transient capillary ITP/zone electrophoresis (CITP/CZE) provides selective analyte enrichment through electrokinetic stacking and extremely high resolving power toward protein and peptide mixtures. The result of the CITP process is that major components may be diluted, but trace compounds are concentrated. The on-column transition of CITP to CZE minimizes additional band broadening while providing superior analyte resolution. Online coupling of transient CITP/CZE with nano-ESI-MS allows ultrasensitive detection of trace peptides at levels of subnanomolar concentration or subfemtomole mass in complex peptide mixtures. More importantly, selective enrichment of trace peptides enables the identification and sequence analysis of low-abundance peptides co-migrated with highly abundant species at a concentration ratio of 1:500,000. The combined CITP/CZE-nano-ESI-MS system is demonstrated to be at least one to two orders of magnitude more sensitive than that attained in conventional electrophoretic and chromatographic-based proteome technologies over a wide dynamic concentration range, potentially allowing comprehensive analysis of protein profiles within a small cell population and limited tissue samples using conventional mass spectrometers. Furthermore, the speed of CITP/CZE separation and the lack of column equilibration in CITP/CZE not only improve the throughput of proteome analysis, but also facilitate its seamless integration with other separation technologies in a multidimensional protein identification platform.

  15. Solid-phase extraction and field-amplified sample injection-capillary zone electrophoresis for the analysis of benzophenone UV filters in environmental water samples. (United States)

    Purrà, Miquel; Cinca, Roser; Legaz, Jessica; Núñez, Oscar


    A field-amplified sample injection-capillary zone electrophoresis (FASI-CZE) method for the analysis of benzophenone (BP) UV filters in environmental water samples was developed, allowing the separation of all compounds in less than 8 min. A 9- to 25-fold sensitivity enhancement was obtained with FASI-CZE, achieving limits of detection down to 21-59 μg/L for most of the analyzed BPs, with acceptable run-to-run and day-to-day precisions (relative standard deviations lower than 17%). In order to remove water sample salinity and to enhance FASI sensitivity, an off-line solid-phase extraction (SPE) procedure using a Strata X polymeric reversed-phase sorbent was used and afforded recoveries up to 72-90% for most BPs. With the combination of off-line SPE and FASI-CZE, limits of detection in the range 0.06-0.6 μg/L in a river water matrix, representing a 2,400- to 6,500-fold enhancement, were obtained. Method performance was evaluated by quantifying a blank river water sample spiked at 1 μg/L. For a 95% confidence level, no statistical differences were observed between found concentrations and spiked concentrations (probability at the confidence level, p value, of 0.60), showing that the proposed off-line SPE-FASI-CZE method is suitable for the analysis of BP UV filters in environmental water samples at low microgram per liter levels. The method was successfully applied to the analysis of BPs in river water samples collected up- and downstream of industrialized and urban areas, and in some drinking water samples.

  16. Usage of Capillary Electrophoresis for screening common Hemoglobinopathies

    Directory of Open Access Journals (Sweden)


    Full Text Available Hemoglobinopathies are most common inherited disorders in the world approximately 7 percent of the worldwide population and 5-6 percent of population of Iran are carriers. For control of this inherited hemoglobin disorders need to accurate screening by more advanced and more accurate methods. This study explains features of current Iran hemoglobin disorders, nominates the accessible methods for screening them and introduces the capillary zone electrophoresis as a rapid & more accurate method. The required data were extracted of various articles and then for good explanation, current Iran hemoglobinopathies properties were showed in the tables and electropherograms of important hemoglobin disorders in Iran population were provided for help to interpretation results of blood tests by capillary zone electrophoresis method. Hemoglobin disorders are including thalassemias & hemoglobin variants Disruption in the production and malfunction of globin chains cause types of hemoglobin disorders. We cannot introduce one of clinical laboratory tests as critical and basic method for screening and distinguishing types of inherited hemoglobin disorders as alone. For distinguishing the types of them must be prepared enough information and data of the hemoglobin disorders and for more accurate analysis must be used simultaneously different methods as Gel electrophoresis, High performance liquid chromatography, Isoelectric focusing, Capillary zone electrophoresis or molecular tests. The capillary electrophoresis is an accurate and rapid method for screening types of the hemoglobin disorders. Other side this method cannot analyze all of them, so must be used biochemical, biophysical and molecular methods for confirmation the results. This review showed we can use the capillary electrophoresis and HPLC as two complementary methods for hemoglobinopathies screening. We can analyze by the methods more hemoglobin disorders and decrease more laboratory errors. Moreover

  17. Classification of Spanish white wines using their electrophoretic profiles obtained by capillary zone electrophoresis with amperometric detection. (United States)

    Arribas, Alberto Sánchez; Martínez-Fernández, Marta; Moreno, Mónica; Bermejo, Esperanza; Zapardiel, Antonio; Chicharro, Manuel


    A method was developed for the simultaneous detection of eight polyphenols (t-resveratrol, (+)-catechin, quercetin and p-coumaric, caffeic, sinapic, ferulic, and gallic acids) by CZE with electrochemical detection. Separation of these polyphenols was achieved within 25 min using a 200 mM borate buffer (pH 9.4) containing 10% methanol as separation electrolyte. Amperometric detection of polyphenols was carried out with a glassy carbon electrode (GCE) modified with a multiwalled carbon nanotubes (CNT) layer obtained from a dispersion of CNT in polyethylenimine. The excellent electrochemical properties of this modified electrode allowed the detection and quantification of the selected polyphenols in white wines without any pretreatment step, showing remarkable signal stability despite the presence of potential fouling substances in wine. The electrophoretic profiles of white wines, obtained using this methodology, have proven to be useful for the classification of these wines by means of chemometric multivariate techniques. Principal component analysis and discriminant analysis allowed accurate classification of wine samples on the basis of their grape varietal (verdejo and airén) using the information contained in selected zones of the electropherogram. The utility of the proposed CZE methodology based on the electrochemical response of CNT-modified electrodes appears to be promising in the field of wine industry and it is expected to be successfully extended to classification of a wider range of wines made of other grape varietals.

  18. Capillary electrophoresis in a fused-silica capillary with surface roughness gradient. (United States)

    Horká, Marie; Šlais, Karel; Karásek, Pavel; Růžička, Filip; Šalplachta, Jiří; Šesták, Jozef; Kahle, Vladislav; Roth, Michal


    The electro-osmotic flow, a significant factor in capillary electrophoretic separations, is very sensitive to small changes in structure and surface roughness of the inner surface of fused silica capillary. Besides a number of negative effects, the electro-osmotic flow can also have a positive effect on the separation. An example could be fused silica capillaries with homogenous surface roughness along their entire separation length as produced by etching with supercritical water. Different strains of methicillin-resistant and methicillin-susceptible Staphylococcus aureus were separated on that type of capillaries. In the present study, fused-silica capillaries with a gradient of surface roughness were prepared and their basic behavior was studied in capillary zone electrophoresis with UV-visible detection. First the influence of the electro-osmotic flow on the peak shape of a marker of electro-osmotic flow, thiourea, has been discussed. An antifungal agent, hydrophobic amphotericin B, and a protein marker, albumin, have been used as model analytes. A significant narrowing of the detected zones of the examined analytes was achieved in supercritical-water-treated capillaries as compared to the electrophoretic separation in smooth capillaries. Minimum detectable amounts of 5 ng/mL amphotericin B and 5 μg/mL albumin were reached with this method.

  19. Sheathless interface for coupling capillary electrophoresis with mass spectrometry (United States)

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.


    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  20. Capillary electrophoresis-mass spectrometry of carbohydrates. (United States)

    Zaia, Joseph


    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust, and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This chapter summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins, and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications.

  1. Improving the sensitivity in chiral capillary electrophoresis. (United States)

    Sánchez-López, Elena; Marina, María Luisa; Crego, Antonio L


    CE is known for being one of the most powerful analytical techniques when performing enantioseparations due to its numerous advantages such as excellent separation efficiency and extremely low solvents and reagents consumption, all of them derived from the capillary small dimensions. Moreover, it is worth highlighting that unlike in chromatographic techniques, in CE the chiral selector is generally within the separation medium instead of being attached to the separation column which makes the method optimization a more versatile task. Despite its numerous advantages, when using UV-Vis detection, CE lacks of sensitivity detection due to its short optical path length derived from the narrow separation capillary. This issue can be overcome by means of different approaches, either by sample treatment procedures or by in-capillary preconcentration techniques or even by employing detection systems more sensitive than UV-Vis, such as LIF or MS. The present review assembles the latest contributions regarding improvements of sensitivity in chiral CE published from June 2013 until May 2015, which follows the works included in a previous review reported by Sánchez-Hernández et al. [Electrophoresis 2014, 35, 12-27].

  2. Capillary electrophoresis with laser-induced fluorescence: environmental applications. (United States)

    Riddick, Lee; Brumley, William C


    Capillary electrophoresis (CE), especially free-zone CE, offers a relatively simple separation with moderate selectivity based on the mobility of ions in solution. Laser-induced fluorescence (LIF) detection, an extremely sensitive technique, can be coupled with a variety of separation conditions to achieve sensitive and quantitative results. When these techniques are combined, CE/LIF provides the sensitivity and increased selectivity that makes trace level environmental analysis of fluorescent compounds possible at or below levels typical for gas chromatography (GC)/mass spectrometry (MS). We offer a panoramic review of the role of these tools in solving environmental and related analytical problems before providing a detailed experimental protocol.

  3. Method for analysing glycoprotein isoforms by capillary electrophoresis


    Frutos, Mercedes de; Díez-Masa, José Carlos; Morales-Cid, Gabriel


    [EN] The present invention relates to a new method for the purification, concentration, separation and determination of the isoforms of alpha-1-acid glycoprotein (AGP) in human blood serum samples using capillary electrophoresis. The new method is based on the immunocapture and preconcentration of the sample within the separation capillary by using an immunoadsorbent phase magnetically immobilized within the electrophoresis capillary and the subsequent desorption and separation of the glycopr...

  4. On-line cation-exchange preconcentration and capillary electrophoresis coupled by tee joint interface. (United States)

    Zhang, Zhao-Xiang; He, You-Zhao


    An on-line preconcentration method based on ion exchange solid phase extraction was developed for the determination of cationic analytes in capillary electrophoresis (CE). The preconcentration-separation system consisted of a preconcentration capillary bonded with carboxyl cation-exchange stationary phase, a separation capillary for zone electrophoresis and a tee joint interface of the capillaries. Two capillaries were connected closely inside a 0.3 mm i.d. polytetrafluoroethylene tube with a side opening and fixed together by the interface. The preparations of the preconcentration capillaries and interface were described in detail in this paper. The on-line preconcentration and separation procedure of the analysis system included washing and conditioning the capillaries, loading analytes, filling with buffer solution, eluting analytes and separating by capillary zone electrophoresis (CZE). Several analysis parameters, including sample loading flow rate and time, eluting solution and volume, inner diameter and length of preconcentration capillary etc., were investigated. The proposed method enhanced the detection sensitivity of CE-UV about 5000 times for propranolol and metoprolol compared with normally electrokinetic injection. The detection limits of propranolol and metoprolol were 0.02 and 0.1 microg/L with the proposed method respectively, whereas those were 0.1 and 0.5 mg/L with conventional electrokinetic injection. The experiment results demonstrate that the proposed technique can increase the preconcentration factor evidently.

  5. Fabricating PFPE Membranes for Capillary Electrophoresis (United States)

    Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason


    A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

  6. Nitromethane as solvent in capillary electrophoresis. (United States)

    Subirats, Xavier; Porras, Simo P; Rosés, Martí; Kenndler, Ernst


    Nitromethane has several properties that make it an interesting solvent for capillary electrophoresis especially for lipophilic analytes that are not sufficiently soluble in water: freezing and boiling points are suitable for laboratory conditions, low viscosity leads to favourable electrophoretic mobilities, or an intermediate dielectric constant enables dissolution of electrolytes. In the present work we investigate the change of electrophoretically relevant analyte properties - mobilities and pKa values - in nitromethane in dependence on the most important experimental conditions determined by the background electrolyte: the ionic strength, I, and the pH. It was found that the mobility decreases with increasing ionic strength (by, e.g. up to 30% from I = 0 to 50 mmol/L) according to theory. An appropriate pH scale is established by the aid of applying different concentration ratios of a buffer acid with known pKa and its conjugate base. The mobility of the anionic analytes (from weak neutral acids) depends on the pH with the typical sigmoidal curve in accordance with theory. The pKa of neutral acids derived from these curves is shifted by as much as 14 pK units in nitromethane compared to water. Both findings confirm the agreement of the electrophoretic behaviour of the analytes with theories of electrolyte solutions. Separation of several neutral analytes was demonstrated upon formation of charged complexes due to heteroconjugation with chloride as ionic constituent of the background electrolyte.

  7. Monitoring of enzymatic reactions using capillary electrophoresis with conductivity detection



    Capillary electrophoresis combined with contactless conductivity detection allows to separate and detect the ionic species, which are neither UV absorbing nor fluorescent. This thesis focuses on the applications of this method on enzymatic reactions in different analytical tasks. First, the non-ionic species ethanol, glucose, ethyl acetate and ethyl butyrate were made accessible for analysis by capillary electrophoresis via charged products or byproducts obtained in enzymati...

  8. Techniques For Focusing In Zone Electrophoresis (United States)

    Sharnez, Rizwan; Twitty, Garland E.; Sammons, David W.


    In two techniques for focusing in zone electrophoresis, force of applied electrical field in each charged particle balanced by restoring force of electro-osmosis. Two techniques: velocity-gradient focusing (VGF), suitable for rectangular electrophoresis chambers; and field-gradient focusing (FGF), suitable for step-shaped electrophoresis chambers.

  9. [Determination of glutamic acid in biological material by capillary electrophoresis]. (United States)

    Narezhnaya, E; Krukier, I; Avrutskaya, V; Degtyareva, A; Igumnova, E A


    The conditions for the identification and determination of Glutamic acid by capillary zone electrophoresis without their preliminary derivatization have been optimized. The effect of concentration of buffer electrolyte and pH on determination of Glutamic acid has been investigated. It is shown that the 5 Mm borate buffer concentration and a pH 9.15 are optimal. Quantitative determination of glutamic acid has been carried out using a linear dependence between the concentration of the analyte and the area of the peak. The accuracy and reproducibility of the determination are confirmed by the method "introduced - found". Glutamic acid has been determined in the placenta homogenate. The duration of analysis doesn't exceed 30 minutes. The results showed a decrease in the level of glutamic acid in cases of pregnancy complicated by placental insufficiency compared with the physiological, and this fact allows to consider the level of glutamic acid as a possible marker of complicated pregnancy.

  10. Separation of cold medicine ingredients by capillary electrophoresis. (United States)

    Suntornsuk, L


    This study demonstrates the separation of cold medicine ingredients (e.g., phenylpropanolamine, dextromethorphan, chlorpheniramine maleate, and paracetamol) by capillary zone electrophoresis and micellar electrokinetic chromatography. Factors affecting their separations were the buffer pH and the concentrations of buffer, surfactant and organic modifiers. Optimum results were obtained with a 10 mM sodium dihydrogen-phosphate-sodium tetraborate buffer containing 50 mM sodium dodecyl sulfate (SDS) and 5% methanol (MeOH), pH 9.0. The carrier electrolyte gave a baseline separation of phenylpropanolamine, dextromethorphan, chlorpheniramine maleate, and paracetamol with a resolution of 1.2, and the total migration time was 11.38 min.

  11. Affinity capillary electrophoresis: the theory of electromigration. (United States)

    Dubský, Pavel; Dvořák, Martin; Ansorge, Martin


    We focus on the state-of-the-art theory of electromigration under single and multiple complexation equilibrium. Only 1:1 complexation stoichiometry is discussed because of its unique status in the field of affinity capillary electrophoresis (ACE). First, we summarize the formulas for the effective mobility in various ACE systems as they appeared since the pioneering days in 1992 up to the most recent theories till 2015. Disturbing phenomena that do not alter the mobility of the analyte directly but cause an unexpected peak broadening have been studied only recently and are also discussed in this paper. Second, we turn our attention to the viscosity effects in ACE. Change in the background electrolyte viscosity is unavoidable in ACE but numerous observations scattered throughout the literature have not been reviewed previously. This leads to an uncritical employment of correction factors that may or may not be appropriate in practice. Finally, we consider the ionic strength effects in ACE, too. Limitations of the current theories are also discussed and the tasks identified where open problems still prevail. Graphical Abstract A weak base (A) undergoes an acidic-basic equilibria (in blue) and migrates with an electrophoretic mobility of [Formula: see text]. Simultaneously, it interacts with a selector (sel) while the analyte-selector complex migrates with an electrophoretic mobility of [Formula: see text]. The strength of the interaction (in orange) is governed by the binding constant, K A , and the concentration of the selector, c sel . This all gives the analyte an effective mobility of [Formula: see text] and moves it out of the zero position (EOF; right top insert). The interaction of the positively charged analyte with the neutral selector slows down the analyte with increasing selector concentration (right bottom insert).

  12. Fluid mechanics of electroosmotic flow and its effect on band broadening in capillary electrophoresis. (United States)

    Ghosal, Sandip


    Electroosmotic flow (EOF) usually accompanies electrophoretic migration of charged species in capillary electrophoresis unless special precautions are taken to suppress it. The presence of the EOF provides certain advantages in separations. It is an alternative to mechanical pumps, which are inefficient and difficult to build at small scales, for transporting reagents and analytes on microfluidic chips. The downside is that any imperfection that distorts the EOF profile reduces the separation efficiency. In this paper, the basic facts about EOF are reviewed from the perspective of fluid mechanics and its effect on separations in free solution capillary zone electrophoresis is discussed in the light of recent advances.

  13. Stability-indicating capillary zone electrophoresis method for the assessment of recombinant human granulocyte-macrophage colony-stimulating factor and its correlation with reversed-phase liquid chromatography method and bioassay. (United States)

    Dalmora, Sergio Luiz; Butzge, Cairo dos Santos; Machado, Francine Trevisan; Walter, Maurício Elesbão; Dalmora, Maria Elisabeth de Ávila; Souto, Ricardo Bizogne


    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of granulocyte-macrophage colony-stimulating factor (rhGM-CSF) using leuprorelin acetate (LA), as internal standard (IS). A fused-silica capillary (75 μm i.d.; effective length, 72 cm) was used at 25 °C; the applied voltage was 12 kV. The background electrolyte solution consisted of 50mM di-sodium hydrogen phosphate solution at pH 8.8. Injections were performed using a pressure mode at 50 mbar for 9s, with detection by photodiode array detector set at 200 nm. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The method was linear over the concentration range of 2.5-200 μg mL(-1) (r(2)=0.9995) and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.79 μg mL(-1) and 2.5 μg mL(-1), respectively. The accuracy was 99.14% with bias lower than 1.40%. The method was applied to the quantitative analysis of biopharmaceutical formulations, and the results were correlated to those of a validated reversed-phase LC method (RP-LC), and an in vitro bioassay, showing non-significant differences (p>0.05).

  14. Enantiomeric resolution of multiple chiral centres racemates by capillary electrophoresis. (United States)

    Ali, Imran; Suhail, Mohd; Al-Othman, Zeid A; Alwarthan, Abdulrahman; Aboul-Enein, Hassan Y


    Enantiomeric resolution of multichiral centre racemates is an important area as some multichiral centre racemates are of great medicinal importance. However, enantioseparation of such types of racemates is a challenging task. Amongst many analytical techniques, capillary electrophoresis is a powerful technique and may be used to resolve such racemates. Only few papers are available describing enantiomeric resolution of such racemates. Therefore, efforts have been made to describe the enantiomeric resolution of multichiral centre racemates by capillary electrophoresis. This article discusses the importance of multichiral racemates, the need for capillary electrophoresis in enantiomeric resolution and chiral resolution of multichiral centre racemates using various chiral selectors. Further, attempts have been made to discuss the future challenges and prospects of enantiomeric resolution of multichiral racemates. The various chiral selectors used for the purpose are chiral crown ether, cyclodextrins, polysaccharides, macrocyclic glycopeptide antibiotics and ligand exchange.

  15. Bundled capillary electrophoresis using microstructured fibres. (United States)

    Rogers, Benjamin; Gibson, Graham T T; Oleschuk, Richard D


    Joule heating, arising from the electric current passing through the capillary, causes many undesired effects in CE that ultimately result in band broadening. The use of narrow-bore capillaries helps to solve this problem as smaller cross-sectional area results in decreased Joule heating and the rate of heat dissipation is increased by the larger surface-to-volume ratio. Issues arising from such small capillaries, such as poor detection sensitivity, low loading capacity and high flow-induced backpressure (complicating capillary loading) can be avoided by using a bundle of small capillaries operating simultaneously that share buffer reservoirs. Microstructured fibres, originally designed as waveguides in the telecommunication industry, are essentially a bundle of parallel ∼5 μm id channels that extend the length of a fibre having otherwise similar dimensions to conventional CE capillaries. This work presents the use of microstructured fibres for CZE, taking advantage of their relatively high surface-to-volume ratio and the small individual size of each channel to effect highly efficient separations, particularly for dye-labelled peptides.

  16. Optimized photonic crystal fibers supporting efficient capillary electrophoresis (United States)

    Calcerrada, M.; García-Ruiz, C.; Roy, P.; Gonzalez-Herraez, M.


    In this paper we present preliminary results on the use of Photonic Crystal Fibers (PCFs) in a conventional capillary electrophoresis system to separate and detect fluorescent species. PCFs show interesting advantages over conventional capillaries for this application, including larger surface-to-volume ratio and potential for higher resolution with comparable sensitivity. Our results illustrate some of these advantages, and we point out the need for stringent tolerances in the fabrication of specific PCFs for this application.

  17. Separation and quantification of cellulases and hemicellulases by capillary electrophoresis

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Kutter, Jörg Peter; Olsson, Lisbeth


    . Current methods are limited in their ability to quantify all of these enzymes when all are present simultaneously in a mixture. Five different cellulases (two cellobiohydrolases and three endoglucanases) and one hemicellulase (endoxylanase) were separated using capillary electrophoresis (CE) in a fused...

  18. Capillary electrophoresis application in metal speciation and complexation characterization (United States)

    Capillary electrophoresis is amenable to the separation of metal ionic species and the characterization of metal-ligand interactions. This book chapter reviews and discusses three representative case studies in applications of CE technology in speciation and reactions of metal with organic molecules...

  19. Study of Oxidation of Glutathione by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    A capillary electrophoresis method for the separation and quantification of reduced glutathione (GSH) and oxidized glutathione (GSSG) was developed. A baseline separation was achieved within five minutes. The effects of time and the concentrations of hydrogen peroxide (H2O2) on the oxidation of GSH were investigated.

  20. Recent advances in combination of capillary electrophoresis with mass spectrometry: methodology and theory. (United States)

    Klepárník, Karel


    This review focuses on the latest development of microseparation electromigration methods in capillaries and microfluidic devices with MS detection and identification. A wide selection of 183 relevant articles covers the literature published from June 2012 till May 2014 as a continuation of the review article on the same topic by Kleparnik [Electrophoresis 2013, 34, 70-86]. Special attention is paid to the new improvements in the theory of instrumentation and methodology of MS interfacing with capillary versions of zone electrophoresis, ITP, and IEF. Ionization methods in MS include ESI, MALDI, and ICP. Although the main attention is paid to the development of instrumentation and methodology, representative examples illustrate also applications in the proteomics, glycomics, metabolomics, biomarker research, forensics, pharmacology, food analysis, and single-cell analysis. The combinations of MS with capillary versions of electrochromatography and micellar electrokinetic chromatography are not included.

  1. Novel cationic polyelectrolyte coatings for capillary electrophoresis. (United States)

    Duša, Filip; Witos, Joanna; Karjalainen, Erno; Viitala, Tapani; Tenhu, Heikki; Wiedmer, Susanne K


    The use of bare fused silica capillary in CE can sometimes be inconvenient due to undesirable effects including adsorption of sample or instability of the EOF. This can often be avoided by coating the inner surface of the capillary. In this work, we present and characterize two novel polyelectrolyte coatings (PECs) poly(2-(methacryloyloxy)ethyl trimethylammonium iodide) (PMOTAI) and poly(3-methyl-1-(4-vinylbenzyl)-imidazolium chloride) (PIL-1) for CE. The coated capillaries were studied using a series of aqueous buffers of varying pH, ionic strength, and composition. Our results show that the investigated polyelectrolytes are usable as semi-permanent (physically adsorbed) coatings with at least five runs stability before a short coating regeneration is necessary. Both PECs showed a considerably decreased stability at pH 11.0. The EOF was higher using Good's buffers than with sodium phosphate buffer at the same pH and ionic strength. The thickness of the PEC layers studied by quartz crystal microbalance was 0.83 and 0.52 nm for PMOTAI and PIL-1, respectively. The hydrophobicity of the PEC layers was determined by analysis of a homologous series of alkyl benzoates and expressed as the distribution constants. Our result demonstrates that both PECs had comparable hydrophobicity, which enabled separation of compounds with log Po/w > 2. The ability to separate cationic drugs was shown with β-blockers, compounds often misused in doping. Both coatings were also able to separate hydrolysis products of the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene acetate at highly acidic conditions, where bare fused silica capillaries failed to accomplish the separation.

  2. Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes. (United States)

    Zhang, Zhenbin; Yan, Xiaojing; Sun, Liangliang; Zhu, Guijie; Dovichi, Norman J


    A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.

  3. Applicability of chemically modified capillaries in chiral capillary electrophoresis for methamphetamine profiling. (United States)

    Iwata, Yuko T; Mikuma, Toshiyasu; Kuwayama, Kenji; Tsujikawa, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Inoue, Hiroyuki


    We examined the applicability of chemically modified capillaries on the chiral capillary electrophoresis of essential compounds for methamphetamine (MA) profiling (MA, amphetamine, ephedrine, pseudoephedrine, norephedrine, and norpseudoephedrine) using highly sulfated γ-cyclodextrin as a chiral selector. Four types of chemically modified capillaries, namely, FunCap-CE/Type D (possessing diol groups), Type A (amino groups), Type C (carboxyl groups), and Type S (sulfate groups), were evaluated. Repeatability, speed, and good chiral resolution sufficient for routine MA profiling were achieved with the Type S capillary.

  4. Simultaneous determination of pyridine-triphenylborane anti-fouling agent and its degradation products in paint-waste samples using capillary zone electrophoresis with field-amplified sample injection. (United States)

    Kaewchuay, Netnapit; Fukushi, Keiichi; Tsuboi, Ai; Okamura, Hideo; Saito, Keiitsu; Hirokawa, Takeshi


    We proposed a capillary zone electrophoresis (CZE) procedure using field-amplified sample injection (FASI) for the simultaneous determination of pyridine-triphenylborane (PTPB) and its degradation products: diphenylborinic acid (DPB), phenylboronic acid (MPB), and phenol. The LODs for PTPB, DPB, MPB, and phenol were, respectively, 0.85, 0.88, 44, and 28 μg L(-1). The RSDs (n = 4) for the analytes listed above were in respective ranges of 6.2 - 14, 5.9 - 10, and 0.49 - 0.62% for the peak area, peak height, and migration time. The compounds were extracted from paint-waste samples collected from shipyards using a siliga-gel column. The extract was dissolved with acetonitrile containing 1% (v/v) pyridine. The samples were then analyzed using CZE, revealing respective concentrations of 0.076 - 0.53, 0.015 - 0.36, 1.7 - 22, and 1.2 - 13 μg g(-1). The proposed FASI-CZE method is a simple and promising procedure that is expected to be useful for the determination of PTPB and its degradation products in paint wastes.

  5. Analysis of polyphenols in wines: correlation between total polyphenolic content and antioxidant potential from photometric measurements. Prediction of cultivars and vintage from capillary zone electrophoresis fingerprints using artificial neural network. (United States)

    Pazourek, J; Gajdosová, D; Spanilá, M; Farková, M; Novotná, K; Havel, J


    The polyphenols (some of them are also called phytoalexins, flavonols, flavanons, flavanonols, flavons, flavanols, and anthocyanines) are usually marked as potent antioxidants or radical scavengers which assist the body cells against oxidation. Polyphenols in wine are also considered to explain so called French paradox (long life aging and low number of coronary diseases despite of high alcohol and fat consumption). The total polyphenolic content (TPC) and total antioxidant potential (TAP) were determined by photometry and found strongly correlated. This finding suggests that the determination of TAP can be replaced by a more simple procedure of TPC determination. Capillary zone electrophoresis (CZE) with preconcentration by solid phase extraction (SPE) was applied for some polyphenols determination and for obtaining electropherograms of the SPE extracts (fingerprints). From mathematical evaluation of the fingerprints, prediction of cultivars and vintage using artificial neural networks (ANN) was done with more than 90% correct prediction. The study was performed on a set of 47 samples of young wines (vintage 1999-2002) from south Moravia (Czech Republic) and New South Wales (Australia).

  6. Capillary electrophoresis using core-based hyperbranched polyethyleneimine (CHPEI) static-coated capillaries. (United States)

    Boonyakong, Cheerapa; Tucker, Sheryl A


    With unique 3-D architecture, the application of core-based hyperbranched polyethyleneimine (CHPEI), as a capillary coating in capillary electrophoresis, is demonstrated by manipulation of the electroosmotic mobility (EOF). CHPEI coatings (CHPEI5, M(w) approximately 5000 and CHPEI25, M(w) approximately 25,000) were physically adsorbed onto the inner surface of bare fused-silica capillary (BFS) via electrostatic interaction of the oppositely charged molecules by rinsing the capillaries with different CHPEI aqueous solutions. The EOF values of the coated capillaries were measured over the pH range of 4.0-9.0. At higher pH (pH >6) the coated capillary surface possesses excess negative charges, which causes the reversal of the EOF. The magnitudes of the EOF obtained from the coated capillaries were three-fold lower than that of BFS capillary. Desirable reproducibility of the EOF with % RSD (n = 5) capillaries were successfully utilized to separate phenolic compounds, B vitamins, as well as basic drugs and related compounds with reasonable analysis time (capillary and capillary).

  7. Determination of Cordycepin in Cordyceps kyushuensis by Capillary Electrophoresis and its Antitumour Activity

    Institute of Scientific and Technical Information of China (English)


    A simple, rapid and low-cost method of determination for cordycepin in Cordyceps kyushuensis by capillary zone electrophoresis (CZE) was developed. Based on the finding that there is a high concentration of cordycepin in both natural and cultured Cordyceps kyushuensis, the in vitro antitumor activity of cordycepin and the water extracts of Cordyceps kyushuensis has been investigated. This is the first report about the antitumor effect of Cordyceps kyushuensis.

  8. Enantiomeric resolution of galanthamine and related drugs used in anti-Alzheimer therapy by means of capillary zone electrophoresis employing derivatized cyclodextrin selectors. (United States)

    Rizzi, A; Schuh, R; Brückner, A; Cvitkovich, B; Kremser, L; Jordis, U; Fröhlich, J; Küenburg, B; Czollner, L


    An analytical assay is presented for the determination of the enantiomeric composition of galanthamine and related synthetic and natural compounds. (-)-Galanthamine is isolated from Galanthus nivalis and is used in this optical pure form in the therapy of Alzheimer's disease. Recent efforts for a total synthesis of unichiral (-)-galanthamine is connected with the need for a fast and reliable assay for the determination of the optical purity of the end product, as well as for optimizing and controlling the final steps in total synthesis particularly the asymmetric transformation of narwedine. In this paper the enantiomeric resolution of these compounds is reported employing a capillary electrophoretic system with beta-cyclodextrin derived chiral selectors. With the proposed system a number of galanthamine and narwedine derived analogous compounds could be separated, including 1-bromo- and N-alkyl-substituted compounds.

  9. Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography. (United States)

    Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang


    Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed.

  10. Capillary electrophoresis and the clinical laboratory. (United States)

    Jabeen, Rukhsana; Payne, Deborah; Wiktorowicz, John; Mohammad, Amin; Petersen, John


    Over the past 15 years, CE as an analytical tool has shown great promise in replacing many conventional clinical laboratory methods, such as electrophoresis and HPLC. CE's appeal was that it was fast, used very small amounts of sample and reagents, was extremely versatile, and was able to separate large and small analytes, whether neutral or charged. Because of this versatility, numerous methods have been developed for analytes that are of clinical interest. Other than molecular diagnostic and forensic laboratories CE has not been able to make a major impact in the United States. In contrast, in Europe and Japan an increasing number of clinical laboratories are using CE. Now that automated multicapillary instruments are commercially available along with cost-effective test kits, CE may yet be accepted as an instrument that will be routinely used in the clinical laboratories. This review will focus on areas where CE has the potential to have the greatest impact on the clinical laboratory. These include analyses of proteins found in serum and urine, hemoglobin (A1c and variants), carbohydrate-deficient transferrin, forensic and therapeutic drug screening, and molecular diagnostics.

  11. Precise small volume sample handling for capillary electrophoresis. (United States)

    Mozafari, Mona; Nachbar, Markus; Deeb, Sami El


    Capillary electrophoresis is one of the most important analytical techniques. Although the injected sample volume in capillary electrophoresis is only in the nanoliter range, most commercial CE-instruments need approximately 50 μL of the sample in the injection vial to perform the analysis. Hence, in order to fully profit from the low injection volumes, smaller vial volumes are required. Thus experiments were performed using silicone oil which has higher density than water (1.09 g/mL) to replace sample dead volume in the vial. The results were compared to those performed without using the silicone oil in the sample vial. As an example five standard proteins namely beta-lactoglobulin, BSA, HSA, Myoglobin and Ovalbumin, and one of the coagulation cascade involved proteins called vitonectin were investigated using capillary electrophoresis. Mobility ratios and peak areas were compared. However no significant changes were observed (RSDs% for mobility ratios and peak areas were better than 0.9% and 5.8% respectively). Afterwards an affinity capillary electrophoresis method was used to investigate the interactions of two proteins, namely HSA and vitronectin, with three ligands namely enoxaparin sodium, unfractionated heparin and pentosan polysulfate sodium (PPS). Mobility shift precision results showed that the employment of the filling has no noticeable effect on any of the protein-ligand interactions. Using a commercial PrinCE instrument and an autosampler the required sample volume is reduced down to 10 μL, and almost this complete volume can be subsequently injected during repeated experiments. This article is protected by copyright. All rights reserved.

  12. Simultaneous quantification of sialyloligosaccharides from human milk by capillary electrophoresis



    The acidic oligosaccharides of human milk are predominantly sialyloligosaccharides. Pathogens that bind sialic acid-containing glycans on their host mucosal surfaces may be inhibited by human milk sialyloligosaccharides, but testing this hypothesis requires their reliable quantification in milk. Sialyloligosaccharides have been quantified by anion exchange HPLC, reverse or normal phase HPLC, and capillary electrophoresis (CE) of fluorescent derivatives; in milk, these oligosaccharides have be...

  13. Attempt to run urinary protein electrophoresis using capillary technique. (United States)

    Falcone, Michele


    The study of urinary protein has a predominant place in the diagnosis of kidney disease. The most common technique is agarose gel electrophoresis (AGE). For several years, the technique of choice applied to the analysis of serum proteins has been CE, a system that uses capillary fused silica, subjected to high voltage to separate and measure serum proteins. The purpose of this paper was to perform capillary electrophoresis on urinary proteins which, at present, are not interpretable due to the many nonspecific peaks visible when using gel electrophoresis. In order to carry out our research, we used a capillary V8 analyzer together with an agarose gel system from the same company. AGE was taken as the reference method, for which urine was used without any pretreatment. For the V8 system, urine was subjected to purification on granular-activated carbon and then inserted into the V8 analyzer, selecting a program suitable for liquids with low protein content. We examined 19 urine samples collected over 24 hrs from both hospitalized and external patients with different types of proteinuria plus a serum diluted 1/61 considered as a control to recognize the bands. Both methods showed the same protein fractions and classified the proteinuria in a similar way.

  14. Analysis of the Content of Stevia Sweeteners by Capillary Zone Electrophoresis%利用毛细管电泳法分析甜菊糖苷的含量

    Institute of Scientific and Technical Information of China (English)

    邵寒娟; 胡涌刚; 丁亮; 沈明山; 陈睦传; 张向红


    This paper introduced an effect capillary zone electrophoresis method for screening of stevia mutation. According to the experimental results, the optimum separation conditions were selected as: 60 mmol/L Tris-tetraborate buffer of pH 8.0, 30 ℃ and 25 KV. Under optimum conditions, the R.S.D. of stevioside migration time for 15 runs was 0.45%. The detector response for stevioside was linear over the range of 7.45×10-5~1.74×10-2 mol/L (r=0.9994). Stevia main sweeteners cound be separated effectively in less than five minutes. This method was applied for determining the variation of stevia main sweeteners after low-energy ions implantation.%本文介绍了一种用毛细管区带电泳法筛选甜菊糖苷突变体的有效方法。根据实验结果,优化的电泳条件为:60 mmol/L Tris-硼酸缓冲液(pH 8.0),柱温30 ℃,工作电压25 kV。优化条件下,甜菊苷(Stevioside)迁移时间的R.S.D为0.45%(15次),且在7.45×10-5~1.74×10-2 mol/L的浓度范围内存在良好的线性关系(r=0.9994),甜菊主要糖苷在5 min内均可实现分离。在优化条件下,本实验研究了低能离子注入后甜菊主要糖苷含量变化,结果令人满意。

  15. The multi-concentration and two-dimensional capillary electrophoresis method for the analysis of drugs in urine samples

    Institute of Scientific and Technical Information of China (English)


    A novel method has been developed by integration of multi-concentration and two-dimensional(2D) capillary electrophoresis(CE) for simultaneous enhancement of detection sensitivity and separation power in complex samples.Capillary zone electrophoresis(CZE) was used as the first dimension separation according to mobilities,from which the effluent fractions were further analyzed by micellar electrokinetic capillary chromatography(MEKC) acting as the second dimension.Cation-selective exhaustive injection(CSEI) preconcentration method was used to introduce more analytes into the capillary.Furthermore,pH junction and sweeping dual concentration strategies were employed to avoid sample zone diffusion at the interface.The resulting electrophoregram was quite different from that of either CZE or MEKC separation.Up to(0.5-1.2) ×104 fold improvements in sensitivity were obtained relative to the conventional electrokinetic injection method.The proposed method was successfully applied to the determination of drugs in human urine.

  16. 毛细管电泳法检测随机尿中香草扁桃酸和肌酐含量%Determination of Vanillylmandelic and Creatinine in Random Urine Using Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    吴惠毅; 杨晋; 孙召东; 李伟; 赵绍林


    Determination of vanillylmandelic(VMA) and Creatinine(CR) in random urine was performed by capillary zone electrophoresis. The effets of some important factors including the running buffer, the separation voltage and the inner diameter of capillary on the separation were investigated. Under the optimum conditions, vanillylmandelic and Creatinine was separated and detected in 13 min. The linear ranges of VMA and CR were 0~500 and 0~4 000 μmol/L, and the detection limits were 1.0 μmol/L for VMA and 50.0 μmol/L for CR. The relative standard deviations(n=10) of migration time and peak atea of VMA and CR were 0. 57%、0. 45% and 3.78% 、2.78%, respectively. No obvious interference caused by other compounds in human urine such as catecholamines, 5-hydroxytryptamine and albumen was observed. The method was applied to the determination of VMA and CR in random urine with satisfactory results.%采用毛细管区带电泳(CZE)对随机尿中香草扁桃酸(Vanillylmandelic Acid,VMA)、肌酐(Creatinine,CR)进行测定.实验优化了缓冲介质、分离电压、毛细管内径等参数.结果表明:在优化条件下,VMA和CR在13 min内可以实现分离检测,VMA和CR分别在0~500 μmol/L和0~4 000 μmol/L范围内与峰面积呈良好的线性关系,检出限(S/N=3)分别为1.0 μmol/L和50.0 μmol/L.VMA和CR迁移时间和峰面积的相对标准偏差(RSD)分别为0.57%、0.45%和3.78%、2.78%,回收率分别为98.36%和98.85%.高香草酸(HVA)、儿茶酚胺、5-羟色胺和清蛋白等对测定结果无干扰.该法用于尿液中VMA和CR检测,取得了满意的结果.

  17. Double-layer poly(vinyl alcohol)-coated capillary for highly sensitive and stable capillary electrophoresis and capillary electrophoresis with mass spectrometry glycan analysis. (United States)

    Zhang, Yi-Wei; Zhao, Ming-Zhe; Liu, Jing-Xin; Zhou, Ying-Lin; Zhang, Xin-Xiang


    Glycosylation plays an important role in protein conformations and functions as well as many biological activities. Capillary electrophoresis combined with various detection methods provided remarkable developments for high-sensitivity glycan profiling. The coating of the capillary is needed for highly polar molecules from complex biosamples. A poly(vinyl alcohol)-coated capillary is commonly utilized in the capillary electrophoresis separation of saccharides sample due to the high-hydrophilicity properties. A modified facile coating workflow was carried out to acquire a novel multiple-layer poly(vinyl alcohol)-coated capillary for highly sensitive and stable analysis of glycans. The migration time fluctuation was used as index in the optimization of layers and a double layer was finally chosen, considering both the effects and simplicity in fabrication. With migration time relative standard deviation less than 1% and theoretical plates kept stable during 100 consecutive separations, the method was presented to be suitable for the analysis of glycosylation with wide linear dynamic range and good reproducibility. The glycan profiling of enzymatically released N-glycans from human serum was obtained by the presented capillary electrophoresis method combined with mass spectrometry detection with acceptable results.

  18. In-capillary detection of fast antibody-peptide binding using fluorescence coupled capillary electrophoresis. (United States)

    Qin, Yuqin; Qiu, Lin; Qin, Haifang; Ding, Shumin; Liu, Li; Teng, Yiwan; Chen, Yao; Wang, Cheli; Li, Jinchen; Wang, Jianhao; Jiang, Pengju


    Herein, we report a technique for detecting the fast binding of antibody-peptide inside a capillary. Anti-HA was mixed and interacted with FAM-labeled HA tag (FAM-E4 ) inside the capillary. Fluorescence coupled capillary electrophoresis (CE-FL) was employed to measure and record the binding process. The efficiency of the antibody-peptide binding on in-capillary assays was found to be affected by the molar ratio. Furthermore, the stability of anti-HA-FAM-E4 complex was investigated as well. The results indicated that E4 YPYDVPDYA (E4) or TAMRA-E4 YPYDVPDYA (TAMRA-E4) had the same binding priorities with anti-HA. The addition of excess E4 or TAMRA-E4 could lead to partial dissociation of the complex and take a two-step mechanism including dissociation and association. This method can be applied to detect a wide range of biomolecular interactions.

  19. Preparation approaches of the coated capillaries with liposomes in capillary electrophoresis. (United States)

    Mei, Jie; Tian, Yan-Ping; He, Wen; Xiao, Yu-Xiu; Wei, Juan; Feng, Yu-Qi


    The use of liposomes as coating materials in capillary electrophoresis has recently emerged as an important and popular research area. There are three preparation methods that are commonly used for coating capillaries with liposomes, namely physical adsorption, avidin-biotin binding and covalent coupling. Herein, the three different coating methods were compared, and the liposome-coated capillaries prepared by these methods were evaluated by studying systematically their EOF characterization and performance (repeatability, reproducibility and lifetime). The amount of immobilized phospholipids and the interactions between liposome or phospholipid membrane and neutral compounds for the liposome-coated capillaries prepared by these methods were also investigated in detail. Finally, the merits and disadvantages for each coating method were reviewed.

  20. Design and evaluation of capillary electrophoresis in dynamically coated capillaries coupled with chemiluminescence detection. (United States)

    Liu, Haiyan; Han, Ning; Zhang, Lingyi; Du, Yiping; Zhang, Weibing


    A dynamic coating capillary electrophoresis coupled with a simplified on-line chemiluminescence detection system was designed and evaluated. In the proposed system, poly-vinylpyrrolidone was used as dynamic coating substance in the separation buffer to reduce the unwanted protein non-specific adsorption, which was first applied in capillary electrophoresis coupling with on-line chemiluminescence detection. In order to avoid complex processing, an ordinary plastic cuvette was modified as a three-way joint. The chemiluminescence reaction conditions and capillary electrophoresis separation conditions were investigated in detail. The results showed that the coated capillary can be injected protein samples at least 30 times continuously with good repeatability. Under optimal conditions, the chemiluminescence relative intensity was linear with the concentration of hemoglobin in the range of 4-1850 μg mL(-1) and the detection limit was 2.0 μg mL(-1) (S/N=3). The relative standard deviation of migration times and peak heights for 40 μg mL(-1) hemoglobin were 2.5% and 4.1% (n=11) respectively. Interference of matrix effects was overcome by the calibration according to standard addition methods. Afterwards, the method was validated successfully and was applied to detect the concentration of hemoglobin in the serum of haemolytic patients.

  1. Penicillin G as a novel chiral selector in capillary electrophoresis. (United States)

    Dixit, Shuchi; Park, Jung Hag


    The penicillin sub-class of β-lactam antibiotics has not been examined for its enantiodiscriminating abilities in capillary electrophoresis (CE) until date. The present work was therefore designed to evaluate penicillin G potassium salt (PenG) as an ion-pair chiral selector (CS) using CE for its several attributes, namely, high solubility in water and lower alcohols, structure allowing multiple interactions with analytes and cost-effectiveness. Systematic experiments were performed to investigate the effect of composition of background electrolyte, applied voltage and capillary temperature on chiral separation. Baseline resolutions of enantiomers of five basic chiral drugs (namely, darifenacin, citalopram, sertraline, propranolol and metoprolol) were attained using a background electrolyte composed of water:methanol (90:10, v/v) and consisting of 10.7 or 16.1mM CS at 20°C using an applied voltage of 5kV.

  2. Separation of Aminobenzoic Acids by Gold Nanoparticle modified Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    YAN,Hongtao; LI,Tuo; GUO,Yanli


    A novel method for the separation of aminobenzoic acids by capillary electrophoresis was developed.The capillary was modified with gold nanoparticles.The effect of gold nanoparticles on the resolution and selectivity of separation was investigated.The influence of separation voltage,pH and buffer concentration on the separation of aminobenzoic acids was also examined.It was found that the presence of gold nanoparticles improved the precision of the analysis and increased the separation efficiency.Under the optimized experiment conditions,aminobenzoic acids were separated and determined.Linearity was established over the concentration range 0.5-40 μg·mL-1 with correlation coefficients of 0.9978-0.9992.The detection limits (S/N = 3) were from 0.1 to 0.5 μg·mL-1.

  3. Photosensitive diazotized poly(ethylene glycol) covalent capillary coatings for analysis of proteins by capillary electrophoresis. (United States)

    Yu, Bing; Chen, Xin; Cong, Hailin; Shu, Xi; Peng, Qiaohong


    A new method for the fabrication of covalently cross-linked capillary coatings of poly(ethylene glycol) (PEG) is described using diazotized PEG (diazo-PEG) as a new photosensitive coating agent. The film of diazo-PEG depends on ionic bonding and was first prepared on the inner surface of capillary by self-assembly, and ionic bonding was converted into covalent bonding after reaction of ultraviolet light with diazo groups through unique photochemical reaction. The covalently bonded coating impedance adsorption of protein on the central surface of capillary and hence the four proteins ribonuclease A, cytochrome c, bovine serum albumin, and lysosome can be baseline separated by using capillary electrophoresis (CE). The covalently cross-linked diazo-PEG capillary column coatings not only improved the CE separation performance for proteins compared to non-covalently cross-linked coatings or bare capillary but also showed a remarkable chemical solidity and repeatability. Because photosensitive diazo-PEG took the place of the highly noxious and silane moisture-sensitive coating reagents in the fabrication of covalent coating, this technique shows the advantage of being environment-friendly and having a high efficiency for CE to make the covalently bonded capillaries.

  4. Characterization and Study of Transgenic Cultivars by Capillary and Microchip Electrophoresis

    Directory of Open Access Journals (Sweden)

    Elena Domínguez Vega


    Full Text Available Advances in biotechnology have increased the demand for suitable analytical techniques for the analysis of genetically modified organisms. Study of the substantial equivalence, discrimination between transgenic and non-transgenic cultivars, study of the unintended effects caused by a genetic modification or their response to diverse situations or stress conditions (e.g., environmental, climatic, infections are some of the concerns that need to be addressed. Capillary electrophoresis (CE is emerging as an alternative to conventional techniques for the study and characterization of genetically modified organisms. This article reviews the most recent applications of CE for the analysis and characterization of transgenic cultivars in the last five years. Different strategies have been described depending on the level analyzed (DNA, proteins or metabolites. Capillary gel electrophoresis (CGE has shown to be particularly useful for the analysis of DNA fragments amplified by PCR. Metabolites and proteins have been mainly separated using capillary zone electrophoresis (CZE using UV and MS detection. Electrophoretic chips have also proven their ability in the analysis of transgenic cultivars and a section describing the new applications is also included.

  5. Subtracting Technique of Baselines for Capillary Electrophoresis Signals

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; MO Jin-yuan; CHEN Zuan-guang; GAO Yan


    The drifting baselines of capillary electrophoresis affect the veracity of analysis greatly. This paper presents Threshold Fitting Technique(TFT) so as to subtract the baselines from the original signals and emendate the signals. In TFT, wav elet and curve fitting technique are applied synthetically, thresholds are decided by the computer automatically. Many experiments of signal processing indicate that TFT is simple for being used, there are few man-induced factors, and the results are satisfactory. TFT can be applied for noisy signals without any pre-processing.

  6. Capillary electrophoresis-electrochemical detection microchip device and supporting circuits (United States)

    Jackson, Douglas J.; Roussel, Jr., Thomas J.; Crain, Mark M.; Baldwin, Richard P.; Keynton, Robert S.; Naber, John F.; Walsh, Kevin M.; Edelen, John. G.


    The present invention is a capillary electrophoresis device, comprising a substrate; a first channel in the substrate, and having a buffer arm and a detection arm; a second channel in the substrate intersecting the first channel, and having a sample arm and a waste arm; a buffer reservoir in fluid communication with the buffer arm; a waste reservoir in fluid communication with the waste arm; a sample reservoir in fluid communication with the sample arm; and a detection reservoir in fluid communication with the detection arm. The detection arm and the buffer arm are of substantially equal length.

  7. Challenges of glycoprotein analysis by microchip capillary gel electrophoresis. (United States)

    Engel, Nicole; Weiss, Victor U; Wenz, Christian; Rüfer, Andreas; Kratzmeier, Martin; Glück, Susanne; Marchetti-Deschmann, Martina; Allmaier, Günter


    Glycosylations severely influence a protein's biological and physicochemical properties. Five exemplary proteins with varying glycan moieties were chosen to establish molecular weight (MW) determination (sizing), quantitation, and sensitivity of detection for microchip capillary gel electrophoresis (MCGE). Although sizing showed increasing deviations from literature values (SDS-PAGE or MALDI-MS) with a concomitant higher degree of analyte glycosylation, the reproducibility of MW determination and accuracy of quantitation with high sensitivity and reliability were demonstrated. Additionally, speed of analysis together with the low level of analyte consumption render MCGE attractive as an alternative to conventional SDS-PAGE.

  8. Capillary electrophoresis coupled with electrochemiluminescence for determination of cloperastine hydrochloride

    Institute of Scientific and Technical Information of China (English)


    Objective To investigate the electrochemiluminescence (ECL) behavior of cloperastine hydrochloride. Methods ECL intensity of tris (2,2′-bipyridyl) rutheniumo(Ⅱ) was enhanced, the method for the determination of cloperastine hydrochloride was established using capillary electrophoresis (CE) coupled with electrochemilumolinescence (ECL) detection. Results Under the optimum conditions, ECL intensity varied linearly with cloperastine hydrochloride concentration from 7.0×10-6g/mL to 1.0×10-4g/mL. The detection l...

  9. A New Denoising Technique for Capillary Electrophoresis Signals

    Institute of Scientific and Technical Information of China (English)

    王瑛; 莫金垣


    Capillary electrophoresis(CE) is a powerful analytical tool in chemistry,Thus,it is valuable to solve the denoising of CE signals.A new denoising method called MWDA which emplosy Mexican Hat wavelet is presented ,It is an efficient chemometrics technique and has been applied successfully in processing CE signals ,Useful information can be extractred even from signals of S/N=1 .After denoising,the peak positions are unchanged and the relative errors of peak height are less than 3%.


    Energy Technology Data Exchange (ETDEWEB)

    Cong, Yongzheng; Rausch, Sarah J.; Geng, Tao; Jambovane, Sachin R.; Kelly, Ryan T.


    Here we show that a closed pneumatic microvalve on a PDMS chip can serve as a semipermeable membrane under an applied potential, enabling current to pass through while blocking the passage of charged analytes. Enrichment of both anionic and cationic species has been demonstrated, and concentration factors of ~70 have been achieved in just 8 s. Once analytes are concentrated, the valve is briefly opened and the sample is hydrodynamically injected onto an integrated microchip or capillary electrophoresis (CE) column. In contrast to existing preconcentration approaches, the membrane-based method described here enables both rapid analyte concentration as well as high resolution separations.

  11. Enantiomeric Separation of Meptazinol Hydrochloride by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    YUYun-qiu; CHENYan; LINi; QIUZhui-bai


    Aim To establish a capillary electrophoresis method for enantiomerie separation of meptazinol hydrochloride. Methods The separation conditions such as cyclodextrin(CD)type, buffer pH, concentration of 2,3,6-O-triInethyl-β-cyclodextrin and organic additives were optimized. An optimum concentration was 30 mmol·L-1 phosphate (pH 7.02)with 10% (W/V) TM-β-CD and 2% acetonitrile. Results Basehne resolution of the enantiomer was readily achieved using 2,3,6-O-trimethyl-β-cyclodextrin. Conclusion This is a convenient method for fast enantiomeric resolution of meptazinol hydrochloride.


    Institute of Scientific and Technical Information of China (English)

    WangMing; LiWei; 等


    Using a standard photolithographical procedure,chenmical wet etching and thermal diffusion bonding technology,a chemical analysis device for Capillary Electrophoresis(CE) has been microfabricated on a planar glass substrate with a cross-column geometry.The channels on the microchip substrate are about 50um deep and 150um wide.By employing amino acids derived from 2,4-DiNitroFluoroBenzen(DNFB) on CE chip channels,the sample manipulating system is studied based on the principle of electrodynamics.


    Institute of Scientific and Technical Information of China (English)

    Wang Ming; Li Wei; Han Jinghong; Cui Dafu


    Using a standard photolithographical procedure, chemical wet etching and thermal diffusion bonding technology, a chemical analysis device for Capillary Electrophoresis(CE) has been microfabricated on a planar glass substrate with a cross-column geometry. The channels on the microchip substrate are about 50μm deep and 150μm wide. By employing amino acids derived from 2,4-DiNitroFluoroBenzen (DNFB) on CE chip channels, the sample manipulating system is studied based on the principle of electrodynamics.

  14. Separation and determination of some carboxylic acids by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Sladkov, V.; Fourest, B


    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  15. A universal concept for stacking neutral analytes in micellar capillary electrophoresis. (United States)

    Palmer, J; Munro, N J; Landers, J P


    Unlike recent studies that have depended on manipulation of separation buffer parameters to facilitate stacking of neutral analytes in micellar capillary electrophoresis (MCE) mode, we have developed a method of stacking based simply on manipulation of the sample matrix. Many solutions for sample stacking in MCE are based on strict control of pH, micelle type, electroosmotic flow (EOF) rate, and separation-mode polarity. However, a universal solution to sample stacking in MCE should allow for free manipulation of separation buffer parameters without substantially affecting separation of analytes. Analogous to sample stacking in capillary zone electrophoresis by invoking field amplification of charged analytes in a low-conductivity sample matrix, the proposed method utilizes a high-conductivity sample matrix to transfer field amplification from the sample zone to the separation buffer. This causes the micellar carrier in the separation buffer to stack before it enters the sample zone. Neutral analytes moving out of the sample zone with EOF are efficiently concentrated at the micelle front. Micelle stacking is induced by simply adding salt to the sample matrix to increase the conductivity 2-3-fold higher than the separation buffer. This solution allows free optimization of separation buffer parameters such as micelle concentration, organic modifiers, and pH, providing a method that may complement virtually any existing MCE protocol without restricting the separation method.

  16. Environmental screening of acidic compounds based on capillary zone electrophoresis/laser-induced fluorescence detection with identification by gas chromatography/mass spectrometry and gas chromatography/high-resolution mass spectrometry. (United States)

    Brumley, W C; Grange, A H; Kelliher, V; Patterson, D B; Montcalm, A; Glassman, J; Farley, J W


    This paper describes the application of capillary zone electrophoresis/laser-induced fluorescence detection (CZE/LIF) to the discovery of acidic compounds in environmental matrixes or the screening of extracts for acidic components. Published studies indicate that coal-derived materials contain a significant fraction of acidic compounds relative to materials derived from petroleum and shales. Such compounds may be useful as marker compounds for site assessment and source apportionment issues, and their identification may be important in toxicological and other health issues. We used deep-UV light from the frequency-doubled Ar ion laser at 244 and 257 nm to study extracts of samples. The CZE/LIF technique possesses good sensitivity and therefore overcomes one of the limitations of CZE with UV detection. The present work depends on high pressure/temperature solvent extraction of polynuclear aromatic hydrocarbon (PNA)-contaminated soil, followed by separation using CZE. The anionic analytes were separated by using borate or phosphate buffer (pH 9.2-12.3) after a chemical class separation. Samples were also characterized by gas chromatography/mass spectrometry (GC/MS) using full scans at low resolution, and elemental compositions were determined unequivocally by GC/high-resolution MS (GC/HRMS) using mass peak profiling (MPP). The similarity of low-resolution electron ionization mass spectra for a standard, 1-hydroxypyrene, and for a series of compounds in a contaminated-soil extract suggested that several types of phenolic and hydroxy-PNAs were present, including hydroxylated derivatives of fluorenes, fluoranthenes, and pyrenes. GC/HRMS using MPP confirmed the elemental compositions of the hydroxyfluorenes and hydroxypyrenes (and presumably hydroxyfluoranthenes) as [C13H10O] and [C16H10O], respectively. A new version of the MPP software was written for the Finnigan-MAT 900S-Trap and was similar to that developed previously for the VG 250SE. Inclusion of a calibration

  17. Online comprehensive two-dimensional ion chromatography × capillary electrophoresis. (United States)

    Ranjbar, Leila; Gaudry, Adam J; Breadmore, Michael C; Shellie, Robert A


    A comprehensively coupled online two-dimensional ion chromatography-capillary electrophoresis (IC × CE) system for quantitative analysis of inorganic anions and organic acids in water is introduced. The system employs an in-house built sequential injection-capillary electrophoresis instrument and a nonfocusing modulation interface comprising a tee-piece and a six-port two-position injection valve that allows comprehensive sampling of the IC effluent. High field strength (+2 kV/cm) enables rapid second-dimension separations in which each peak eluted from the first-dimension separation column is analyzed at least three times in the second dimension. The IC × CE approach has been successfully used to resolve a suite of haloacetic acids, dalapon, and common inorganic anions. Two-dimensional peak capacity for IC × CE was 498 with a peak production rate of 9 peaks/min. Linear calibration curves were obtained for all analytes from 5 to 225 ng/mL (except dibromoacetic acid (10-225 ng/mL) and tribromoacetic acid (25-225 ng/mL)). The developed approach was used to analyze a spiked tap water sample, with good measured recoveries (69-119%).

  18. Monitoring compliance to therapy during addiction treatments by means of hair analysis for drugs and drug metabolites using capillary zone electrophoresis coupled to time-of-flight mass spectrometry. (United States)

    Gottardo, Rossella; Fanigliulo, Ameriga; Sorio, Daniela; Liotta, Eloisa; Bortolotti, Federica; Tagliaro, Franco


    Capillary electrophoresis coupled to time-of-flight mass spectrometry was used in the present work for the determination of therapeutic and abused drugs and their metabolites in the hair of subjects undergoing addiction treatments, in order to monitor their compliance to therapy. For this purpose a rapid, qualitative drug screening method was adopted based on capillary electrophoresis hyphenated with time-of-flight mass spectrometry, which had earlier been developed and validated for the forensic-toxicological analysis of hair, limitedly to illicit/abused drugs [1]. Sampling of hair was carried out in order to refer to a time window of about two months from the date of sampling (i.e. 2cm ca. from cortex). A single extraction procedure was applied, allowing the determination in the hair matrix of "drugs of abuse" referred to the past abuses, and therapeutic drugs prescribed in the detoxification program as well as their metabolites. Analyte identification was based on accurate mass measurements and comparison of isotope patterns, providing the most likely matching between accurate mass value and elemental formula. Small molecules (forensic and toxicological interest could be identified unambiguously using mass spectrometric conditions tailored to meet a mass accuracy ≤5ppm. In the present study, the proposed approach proved suitable for the rapid broad spectrum screening of hair samples, although needing further confirmation of results by using fragmentation mass spectrometry.

  19. In-capillary derivatization and capillary electrophoresis separation of amino acid neurotransmitters from brain microdialysis samples. (United States)

    Denoroy, Luc; Parrot, Sandrine; Renaud, Louis; Renaud, Bernard; Zimmer, Luc


    A new in-capillary derivatization method with naphtalene-2,3-dicarboxyaldehyde (NDA)/CN(-) has been developed for capillary electrophoresis with laser-induced fluorescence detection of brain microdialysate amino acids. Samples are sandwiched between two plugs of reagent mixture at the capillary inlet and subsequently separated. Highest derivatization yields are obtained by using a reagent to sample plug length ratio equal to 4, performing a first electrophoretic mixing followed by a zero potential amplification step before applying the separation voltage and using a NaCN to NDA concentration ratio equal to 1. This new single-step methodology allows the analysis of amino acid neurotransmitters in rat brain microdialysis samples.

  20. 生物碱样品中有效成分的CZE法分离与测定%Separation and Determination of Effective Compounds in Alkaloidal Samples by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    高苏亚; 王黎; 王树春; 李华


    建立了一种简单的同时分离测定生物碱样品中咖啡因、可可碱和茶碱3种有效成分的区带毛细管电泳法.采用未涂层石英毛细管(75 μm i.d.×60 cm,有效长度50 cm),以20 mmol·L-1硼砂-4 mmol·L-1β-CD (pH 9.0)为运行缓冲液,压力(0.5 psi)进样5 s,运行电压16 kV,检测波长273 nm,温度25℃.在优化的实验条件下,3种生物碱的电泳谱图峰面积与其质量浓度在0.036~0.288 g·L-1呈良好线性关系(r≥0.9984);方法的精密度、重复性和稳定性良好,其峰面积的RSD均不大于3.2%,其检出限均不大于2.7mg·L-1;加标回收率为97%~ 104%.该方法简单、快速、试剂消耗少,可用于生物碱样品中咖啡因、可可碱和茶碱的分离与测定.%A capillary zone electrophoresis(CZE) method was established for the separation and determination of three effective compounds such as caffeine, theobromine and theophylline in alkaloidal samples. The sample was separated on an uncoated silica capillary (75 μm i. d.×60 cm, effective length; 50 cm) using pH 9. 0 20 mmol . L-1 borate containing 4 mmol . L-1 beta-cyclodextrin (β-CD) as running buffer. The pressure of injection was set at 0. 5 psi and the time was set 5 s. The detection wavelength was 273 run. A voltage of 16 kV was applied at 25 ℃. Under the optimal conditions, good linear relationships were observed between peak areas and alkaloidal concentrations in the range of 0. 036 -0. 288 g . L-1, with correlation coefficients not less than 0. 998 4. The RSDs of the peak area were not more than 3. 2% . The limits of detection ( LODs) were not more than 2. 7 mg . L-1. The average recoveries were in the range of 97% - 104% . This method is simple, quick and less reagent-consuming, and is suitable for the separation and determination of the three alkaloids in real samples.

  1. 毛细管区带电泳法分析不同来源血竭中龙血素A和龙血素B%Determination of loureirin A and loureirin B in dragon's blood by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    杨雪滢; 胡旭芳; 李菲; 王兴红; 曹秋娥


    A capillary zone electrophoresis method (CZE) for the simultaneous determination of loureirin A and loureirin B was developed based on the optimized conditions of the pH, composition and concentration of the running buffer solution. Loureirin A and loureirin B were separated and determined effectively within 15 min in a running buffer solution of 20 mmol/L Na2B4O7(pH 9. 98 adjusted with NaOH solution) containing 10.0% (v/v) acetonitrile, 5.0% (v/v) ethylene glycol and 1.0% (v/v) butanol, with the applied voltage of 20 kV, capillary temperature of 25℃, detection wavelength of 211 nm, and injection of 5 s at 3 447 Pa. The linear ranges for the determination of loureirin A and loureirin B were 1. 00 - 100 mg/L and 0. 50-100 mg/L, respectively. The determination of loureirin A and loureirin B in dragon' s blood from natural and artificial inoculation was performed by the proposed method. The relative standard deviations for the determination of the two constituents in samples were from 0. 6% to 3. 8%, and the recoveries ranged between 95. 1% and 105. 8%. The method is simple, rapid and possesses higher reproducibility and efficiency. It can be used for the determination of loureirin A and loureirin B in dragon' s blood.%在系统优化了电解质溶液的pH、组成、浓度及仪器条件的基础上,建立了一种测定不同来源血竭中龙血素A和龙血素B的毛细管区带电泳(CZE)方法.采用20 kV的分离电压,25℃的毛细管柱温,211 nm的检测波长以及5s的压力(3447 Pa)进样时间,在20 mmol/L的Na2B4O7缓冲溶液(用NaOH调节pH到9.98,含有10%(v/v,下同)乙腈、5.0%乙二醇和1.0%正丁醇)中,龙血素A和龙血素B在15 min内得到了有效分离与检测.方法的线性范围对于龙血素A和龙血素B分别为1.0~100.0mg/L和0.5~100.0 mg/L.将该方法用于天然血竭及人工诱导血竭中龙血素A和龙血素B的测定,相对标准偏差在0.6% ~ 3.8%之间,加标回收率在95.1%~105.8%之间.

  2. Analytical characterization of wine and its precursors by capillary electrophoresis. (United States)

    Gomez, Federico J V; Monasterio, Romina P; Vargas, Verónica Carolina Soto; Silva, María F


    The accurate determination of marker chemical species in grape, musts, and wines presents a unique analytical challenge with high impact on diverse areas of knowledge such as health, plant physiology, and economy. Capillary electromigration techniques have emerged as a powerful tool, allowing the separation and identification of highly polar compounds that cannot be easily separated by traditional HPLC methods, providing complementary information and permitting the simultaneous analysis of analytes with different nature in a single run. The main advantage of CE over traditional methods for wine analysis is that in most cases samples require no treatment other than filtration. The purpose of this article is to present a revision on capillary electromigration methods applied to the analysis of wine and its precursors over the last decade. The current state of the art of the topic is evaluated, with special emphasis on the natural compounds that have allowed wine to be considered as a functional food. The most representative revised compounds are phenolic compounds, amino acids, proteins, elemental species, mycotoxins, and organic acids. Finally, a discussion on future trends of the role of capillary electrophoresis in the field of analytical characterization of wines for routine analysis, wine classification, as well as multidisciplinary aspects of the so-called "from soil to glass" chain is presented.

  3. Recent developments in capillary and chip electrophoresis of bioparticles: Viruses, organelles, and cells. (United States)

    Subirats, Xavier; Blaas, Dieter; Kenndler, Ernst


    In appropriate aqueous buffer solutions, biological particles usually exhibit a particular electric surface charge due to exposed charged or chargeable functional groups (amino acid residues, acidic carbohydrate moieties, etc.). Consequently, these bioparticles can migrate in solution under the influence of an electric field allowing separation according to their electrophoretic mobilities or their pI values. Based on these properties, electromigration methods are of eminent interest for the characterization, separation, and detection of such particles. The present review discusses the research papers published between 2008 and 2010 dealing with isoelectric focusing and zone electrophoresis of viruses, organelles and microorganisms (bacteria and yeast cells) in the capillary and the chip format.

  4. Use of Capillary Electrophoresis in the Study of Interaction between dsDNA and Drug Molecules

    Institute of Scientific and Technical Information of China (English)


    Two 17-mer dsDNA with different sequence characteristics were designed to investigate the binding characteristics of berberine, an anticancer drug with uncertain binding mode, and Hoechst 33258, a model DNA minor groove binder, with dsDNA, respectively by the capillary zone electrophoresis (CZE). Kenndler model analysis revealed that Hoechst 33258 exhibited intermediate affinity with dsDNA, while there was only low affinity and some weak binding preference for AATT-containing to GGCC-containing dsDNA for berberine.

  5. Capillary electrophoresis-mass spectrometry using noncovalently coated capillaries for the analysis of biopharmaceuticals. (United States)

    Haselberg, R; Brinks, V; Hawe, A; de Jong, G J; Somsen, G W


    In this work, the usefulness of capillary electrophoresis-electrospray ionization time-of-flight-mass spectrometry for the analysis of biopharmaceuticals was studied. Noncovalently bound capillary coatings consisting of Polybrene-poly(vinyl sulfonic acid) or Polybrene-dextran sulfate-Polybrene were used to minimize protein and peptide adsorption, and achieve good separation efficiencies. The potential of the capillary electrophoresis-mass spectrometry (CE-MS) system to characterize degradation products was investigated by analyzing samples of the drugs, recombinant human growth hormone (rhGH) and oxytocin, which had been subjected to prolonged storage, heat exposure, and/or different pH values. Modifications could be assigned based on accurate masses as obtained with time-of-flight-mass spectrometry (TOF-MS) and migration times with respect to the parent compound. For heat-exposed rhGH, oxidations, sulfonate formation, and deamidations were observed. Oxytocin showed strong deamidation (up to 40%) upon heat exposure at low pH, whereas at medium and high pH, mainly dimer (>10%) and trisulfide formation (6-7%) occurred. Recombinant human interferon-β-1a (rhIFN-β) was used to evaluate the capability of the CE-MS method to assess glycan heterogeneity of pharmaceutical proteins. Analysis of this N-glycosylated protein revealed a cluster of resolved peaks which appeared to be caused by at least ten glycoforms differing merely in sialic acid and hexose N-acetylhexosamine composition. Based on the relative peak area (assuming an equimolar response per glycoform), a quantitative profile could be derived with the disialytated biantennary glycoform as most abundant (52%). Such a profile may be useful for in-process and quality control of rhIFN-β batches. It is concluded that the separation power provided by combined capillary electrophoresis and TOF-MS allows discrimination of highly related protein species.

  6. Carbon Fiber-gold/mercury Dual-electrode Detection for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    A carbon fiber-gold/mercury dual-electrode for capillary electrophoresis is constructed. Cysteine, glutathione, ascorbic acid and uric acid can be detected simultaneously and selectively at the dual-electrode, respectively. The capillary electrophoresis / dual-electrode detection system has been used to determine these compounds in human blood samples.

  7. Determination of Enantiomeric Excess of Glutamic Acids by Lab-made Capillary Array Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Jun WANG; Kai Ying LIU; Li WANG; Ji Ling BAI


    Simulated enantiomeric excess of glutamic acid was determined by a lab-made sixteen-channel capillary array electrophoresis with confocal fluorescent rotary scanner. The experimental results indicated that the capillary array electrophoresis method can accurately determine the enantiomeric excess of glutamic acid and can be used for high-throughput screening system for combinatorial asymmetric catalysis.

  8. Gene analysis of multiple oral bacteria by the polymerase chain reaction coupled with capillary polymer electrophoresis. (United States)

    Liu, Chenchen; Yamaguchi, Yoshinori; Sekine, Shinichi; Ni, Yi; Li, Zhenqing; Zhu, Xifang; Dou, Xiaoming


    Capillary polymer electrophoresis is identified as a promising technology for the analysis of DNA from bacteria, virus and cell samples. In this paper, we propose an innovative capillary polymer electrophoresis protocol for the quantification of polymerase chain reaction products. The internal standard method was modified and applied to capillary polymer electrophoresis. The precision of our modified internal standard protocol was evaluated by measuring the relative standard deviation of intermediate capillary polymer electrophoresis experiments. Results showed that the relative standard deviation was reduced from 12.4-15.1 to 0.6-2.3%. Linear regression tests were also implemented to validate our protocol. The modified internal standard method showed good linearity and robust properties. Finally, the ease of our method was illustrated by analyzing a real clinical oral sample using a one-run capillary polymer electrophoresis experiment.

  9. Cutting-edge capillary electrophoresis characterization of monoclonal antibodies and related products. (United States)

    Gahoual, Rabah; Beck, Alain; Leize-Wagner, Emmanuelle; François, Yannis-Nicolas


    Out of all categories, monoclonal antibodies (mAbs), biosimilar, antibody-drug conjugates (ADCs) and Fc-fusion proteins attract the most interest due to their strong therapeutic potency and specificity. Because of their intrinsic complexity due to a large number of micro-heterogeneities, there is a crucial need of analytical methods to provide comprehensive in-depth characterization of these molecules. CE presents some obvious benefits as high resolution separation and miniaturized format to be widely applied to the analysis of biopharmaceuticals. CE is an effective method for the separation of proteins at different levels. capillary gel electrophoresis (CGE), capillary isoelectric focusing (cIEF) and capillary zone electrophoresis (CZE) have been particularly relevant for the characterization of size and charge variants of intact and reduced mAbs, while CE-MS appears to be a promising analytical tool to assess the primary structure of mAbs and related products. This review will be dedicated to detail the current and state-of-the-art CE-based methods for the characterization of mAbs and related products.

  10. Analysis of serotonin in brain microdialysates using capillary electrophoresis and native laser-induced fluorescence detection. (United States)

    Benturquia, Nadia; Couderc, François; Sauvinet, Valérie; Orset, Cyrille; Parrot, Sandrine; Bayle, Christophe; Renaud, Bernard; Denoroy, Luc


    Serotonin or 5-hydroxytryptamine (5-HT) is a major neurotransmitter in the central nervous system. In this work, a method for analyzing 5-HT in brain microdialysis samples using a commercially available capillary electrophoresis (CE) system has been developed. A pH-mediated in-capillary preconcentration of samples was performed, and after separation by capillary zone electrophoresis, native fluorescence of 5-HT was detected by a 266 nm solid-state laser. The separation conditions for the analysis of 5-HT in standard solutions and microdialysates have been optimized, and this method has been validated on both pharmacological and analytical bases. Separation of 5-HT was performed using a 80 mmol/L citrate buffer, pH 2.5, containing 20 mmol/L hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and +30 kV voltage. The detection limit was 2.5 x 10(-10) mol/L. This method allows the in vivo brain monitoring of 5-HT using a simple, accurate CE measurement in underivatized microdialysis samples.

  11. Separation of enantiomers by capillary electrophoresis using pentosan polysulfate. (United States)

    Wang, X; Lee, J T; Armstrong, D W


    Pentosan polysulfate, a semisynthetic polysaccharide, was employed as a chiral run buffer additive in capillary electrophoresis. Twenty-eight racemic analytes were resolved. The separations were successful only at low pH when the analytes were significantly protonated. This suggests that ionic interactions were the dominant associative interactions between the anionic pentosan polysulfate and the positively charged analytes. Compared to other linear, carbohydrate-based chiral selectors (i.e., chondroitin sulfates, heparin and dextran sulfate) pentosan polysulfate has some characteristics common of anionic polysaccharides; yet it has several differences in its structure and properties which account for its unusual enantioselectivity. The effects of pH, concentration of phosphate buffer, concentration of pentosan polysulfate and the type and concentration of organic modifier on the enantiomeric separations were investigated. The optimization of these separations were dependent on the nature of the analytes and could be achieved by the proper choice of experimental conditions.

  12. The new approach of standardization of capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    LI; Hua; WANG; Kang; JOSEF; Havel


    In this paper, we develope the new standardization methods to eliminate the influence in capillary electrophoresis (CE). The markers were used to determine the basis position and then correct the data of sample by the migration time of standard sample, and make the migration time of samples consistent with the standard sample by the criterion of the marker. The problem of time transition was corrected in this way. Then according to the peak height or peak area of the marker in the sample (peak height was used here) compared with the standard sample, the sample data was zoomed appropriately. The absorbance error was made to be correct.The wavelet de-noise method was also used to make the data smooth and get a good baseline.

  13. Cyclodextrins in capillary electrophoresis: recent developments and new trends. (United States)

    Escuder-Gilabert, L; Martín-Biosca, Y; Medina-Hernández, M J; Sagrado, S


    Despite the fact that extensive research in the field of separations by capillary electrophoresis (CE) has been carried out and many reviews have been published in the last years, a specific review on the use and future potential of cyclodextrins (CDs) in CE is not available. This review focuses the attention in the CD-CE topic over the January 2013-February 2014 period (not covered by previous more general CE-reviews). Recent contributions (reviews and research articles) including practical uses (e.g. solute-CD binding constant estimation and further potentials; 19% of publications), developments and applications (mainly chiral and achiral analysis; 38 and 24% of publications, respectively) are summarized in nine comprehensive tables and are commented. Statistics and predictions related to the CD-CE publications are highlighted in order to infer the current and expected research interests. Finally, trends and initiatives on CD-CE attending to real needs or practical criteria are outlined.

  14. Separation of ions in acidic solution by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, M.


    Capillary electrophoresis (CE) is an effective method for separating ionic species according to differences in their electrophoretic mobilities. CE separations of amino acids by direct detection are difficult due to their similar electrophoretic mobilities and low absorbances. However, native amino acids can be separated by CE as cations at a low pH by adding an alkanesulfonic acid to the electrolyte carrier which imparts selectivity to the system. Derivatization is unnecessary when direct UV detection is used at 185 nm. Simultaneous speciation of metal cations such as vanadium (IV) and vanadium (V) can easily be performed without complexation prior to analysis. An indirect UV detection scheme for acidic conditions was also developed using guanidine as the background carrier electrolyte (BCE) for the indirect detection of metal cations. Three chapters have been removed for separate processing. This report contains introductory material, references, and general conclusions. 80 refs.

  15. Recent developments in electrochemical detection for microchip capillary electrophoresis. (United States)

    Vandaveer, Walter R; Pasas-Farmer, Stephanie A; Fischer, David J; Frankenfeld, Celeste N; Lunte, Susan M


    Significant progress in the development of miniaturized microfluidic systems has occurred since their inception over a decade ago. This is primarily due to the numerous advantages of microchip analysis, including the ability to analyze minute samples, speed of analysis, reduced cost and waste, and portability. This review focuses on recent developments in integrating electrochemical (EC) detection with microchip capillary electrophoresis (CE). These detection modes include amperometry, conductimetry, and potentiometry. EC detection is ideal for use with microchip CE systems because it can be easily miniaturized with no diminution in analytical performance. Advances in microchip format, electrode material and design, decoupling of the detector from the separation field, and integration of sample preparation, separation, and detection on-chip are discussed. Microchip CEEC applications for enzyme/immunoassays, clinical and environmental assays, as well as the detection of neurotransmitters are also described.

  16. Microchip capillary electrophoresis based electroanalysis of triazine herbicides. (United States)

    Islam, Kamrul; Chand, Rohit; Han, Dawoon; Kim, Yong-Sang


    The number of pesticides used in agriculture is increasing steadily, leading to contamination of soil and drinking water. Herein, we present a microfluidic platform to detect the extent of contamination in soil samples. A microchip capillary electrophoresis system with in-channel electrodes was fabricated for label-free electroanalytical detection of triazine herbicides. The sample mixture contained three representative triazines: simazine, atrazine and ametryn. The electropherogram for each individual injection of simazine, atrazine and ametryn showed peaks at 58, 66 and 72 s whereas a mixture of them showed distinct peaks at 59, 67 and 71 s respectively. The technique as such may prove to be a useful qualitative and quantitative tool for the similar environmental pollutants.

  17. Analysis of anions in ambient aerosols by microchip capillary electrophoresis. (United States)

    Liu, Yan; MacDonald, David A; Yu, Xiao-Ying; Hering, Susanne V; Collett, Jeffrey L; Henry, Charles S


    We describe a microchip capillary electrophoresis method for the analysis of nitrate and sulfate in ambient aerosols. Investigating the chemical composition of ambient aerosol particles is essential for understanding their sources and effects. Significant progress has been made towards developing mass spectrometry-based instrumentation for rapid qualitative analysis of aerosols. Alternative methods for rapid quantification of selected high abundance compounds are needed to augment the capacity for widespread routine analysis. Such methods could provide much higher temporal and spatial resolution than can be achieved currently. Inorganic anions comprise a large percentage of particulate mass, with nitrate and sulfate among the most abundant species. While ion chromatography has proven very useful for analyzing extracts of time-integrated ambient aerosol samples collected on filters and for semi-continuous, on-line particle composition measurements, there is a growing need for development of new compact, inexpensive approaches to routine on-line aerosol ion analysis for deployment in spatially dense, atmospheric measurement networks. Microchip capillary electrophoresis provides the necessary speed and portability to address this need. In this report, on-column contact conductivity detection is used with hydrodynamic injection to create a simple microchip instrument for analysis of nitrate and sulfate. On-column contact conductivity detection was achieved using a Pd decoupler placed upstream from the working electrodes. Microchips containing two Au or Pd working electrodes showed a good linear range (5-500 microM) and low limits-of-detection for sulfate and nitrate, with Au providing the lowest detection limits (1 microM) for both ions. The completed microchip system was used to analyze ambient aerosol filter samples. Nitrate and sulfate concentrations measured by the microchip matched the concentrations measured by ion chromatography.

  18. Affinity capillary electrophoresis method for investigation of bile salts complexation with sulfobutyl ether-ß-cyclodextrin

    DEFF Research Database (Denmark)

    Østergaard, Jesper; Jensen, Henrik; Holm, Rene


    an influence on the ionic strength of the background electrolyte when the cyclodextrin is used in capillary electrophoresis. Mobility-shift affinity capillary methods for investigation of the complexation of taurocholate and taurochenodeoxycholate with the negatively charged cyclodextrin derivative applying...... constant power and ionic strength conditions as well as constant voltage and varying ionic strength were investigated. A new approach for the correction of background electrolyte ionic strength was developed. Mobility-shift affinity capillary electrophoresis experiments obtained at constant voltage...

  19. Determination of acidity constants of enolisable compounds by capillary electrophoresis. (United States)

    Mofaddel, N; Bar, N; Villemin, D; Desbène, P L


    Research on the structure-activity relationships of molecules with acidic carbon atoms led us to undertake a feasibility study on the determination of their acidity constants by capillary electrophoresis (CE). The studied molecules had diverse structures and were tetronic acid, acetylacetone, diethylmalonate, Meldrum's acid, 3-methylrhodanine, nitroacetic acid ethyl ester, pyrimidine-2,4,6-trione, 3-oxo-3-phenylpropionic acid ethyl ester, 1-phenylbutan-1,3-dione, 5,5-dimethylcyclohexan-1,3-dione and homophthalic anhydride. The p Ka range explored by CE was therefore very large (from 3 to 12) and p Ka values near 12 were evaluated by mathematical extrapolations. The analyses were carried out in CZE mode using a fused silica capillary grafted (or not) with hexadimethrine. Owing to the electrophoretic behaviour of these compounds according to the pH, their acidity constants could be evaluated and appeared in perfect agreement with the literature data obtained, a few decades ago, by means of potentiometry, spectrometry or conductimetry. The p Ka of homophthalic anhydride and 3-methylrhodanine were evaluated for the first time.

  20. A new post-column reactor-laser induced fluorescence detector for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Liling


    Capillary zone electrophoresis (CZE), a powerful separation method based on the differential migration of charged species under the influence of an electric field, has been widely used for separations covering from small ions to big biomolecules. Chapter 1 describes the method, then discusses detection of the separated analytes by laser induced fluorescence and by chemical derivatization, and the use of O-phthaldialdehyde (OPA) as a post-column reagent. Chapter 2 describes a post-column reactor which uses two narrow bore capillaries connected coaxially. This reactor differs from other coaxial reactors in terms of capillary dimensions, reagent flow control, ease of construction and most importantly, better limits of detection. The derivatization reagent is electroosmotically driven into the reaction capillary and the reagent flow rate is independently controlled by a high voltage power supply. Amino acids, amines and proteins, derivatized by OPA/2-mercaptoethanol using this post-column reactor coupled with LIF detection, show low attomole mass limits of detection, and for the first time, the authors demonstrate single cell capability with a post-column derivatization scheme. The single cell capability shows that this reactor could find applications in assaying non-fluorescent or electrochemically inactive components in individual biological cells in the future.

  1. Application of capillary electrophoresis to the simultaneous determination and stability study of four extensively used penicillin derivatives

    Directory of Open Access Journals (Sweden)

    Brigitta Simon


    Full Text Available The applicability of capillary electrophoresis for the analysis of four extensively used penicillin derivatives (benzylpenicillin, ampicillin, amoxicillin, oxacilllin has been studied. Because of structural similarities, the electrophoretic behavior of these derivatives is very similar; consequently an efficient separation using the conventional capillary zone electrophoresis is hard to be achieved. Their simultaneous separation was solved by using micellar electrokinetic capillary chromatography, the separation being based on the differential partition of the analytes between the micellar and aqueous phase. Using a buffer solution containing 25 mM sodium tetraborate and 100 mM sodium dodecyl sulfate as surfactant, at a pH of 9.3, applying a voltage of + 25 kV at a temperature of 25 °C, we achieved the simultaneous separation of the studied penicillin derivatives in less then 5 minutes. The separation conditions were optimized and the analytical performance of the method was evaluated in terms of precision, linearity, limit of detection, and quantification. Also, a simple capillary zone electrophoresis method was applied to study the stability of the studied penicillin derivatives in water at different temperatures, using ciprofloxacin hydrochloride as internal standard. It was observed that the extent of the hydrolysis of penicillins in water is highly dependent on the time and also temperature.

  2. Impact of capillary conditioning and background electrolyte composition on capillary electrophoresis analysis of prostate specific antigen isoforms. (United States)

    Farina-Gomez, Noemi; Puerta, Angel; Gonzalez, Monica; Diez-Masa, Jose Carlos; de Frutos, Mercedes


    Glycoproteins expressed in the human body can experience modifications as result of pathological situations. Detection of those changes can be useful as disease biomarkers. As a result of these modifications, size and/or electrical charge of the glycoprotein can be altered. Migration in capillary zone electrophoresis (CZE) is governed by the size to charge ratio of the analyte and therefore this separation technique can be used to monitor those modifications. At its turn, the alteration of the electrophoretical pattern of a given glycoprotein could be used as disease biomarker. To this aim, high repeatability for separation of a large number of peaks for a given glycoprotein is desirable. For prostate cancer, new markers are needed to decrease the high number of false positive results provided by the biomarkers currently used in clinics. In this sense, CZE methods for analysis of the several prostate specific antigen (PSA) peaks which this glycoprotein exhibit, called isoforms and containing one or more glycoforms, could be useful to study the PSA pattern as prostate cancer marker. In this study two complementary strategies to achieve both lot-to-lot capillary repeatability and high resolution of a large number of PSA isoforms are developed. Better performance and precision have been obtained for capillaries conditioned with HCl than for those conditioned with NaOH. Optimization of the background electrolyte (BGE) pH value to 8.0 and inclusion of 3M urea on its composition were the two factors of highest impact for enhancing resolution of the highest number of PSA peaks. Under the optimized conditions for capillary conditioning and BGE pH and composition, long-term resolution of 10 isoforms of PSA was achieved. Inter-day (n=3) %RSD was 0.55 for the ratio tm/tEOF, 1.15 for μeff, and 5.02 for % Acorr of the PSA peaks.

  3. Rapid determination of cyclamate in foods by capillary zone electrophoresis with indirect ultraviolet detection%毛细管区带电泳-间接紫外法快速测定食品中的甜蜜素

    Institute of Scientific and Technical Information of China (English)

    陈桐; 丁晓静; 李一正; 赵旭东; 赵珊


    建立了毛细管区带电泳-间接紫外法快速测定食品中甜蜜素的新方法。液体样品用超纯水稀释后直接进样;固体样品经粉碎或剪碎后用超纯水超声提取后离心,上清液直接进样或用水稀释后进样。以未涂敷石英毛细管(80 cm×75μm,有效长度:70 cm)为分离柱,以2 mmol / L 苯甲酸钠+10 mmol / L 碳酸钠+0.5 mmol / L 十六烷基三甲基溴化铵为分离缓冲液;于200 nm 波长处检测。检出限为8.9 mg / kg(S / N =3),定量限为26.7 mg / kg(S / N =9)。低、中、高添加水平的加标回收率分别为93.4%、100.3%及101.9%,相应的 RSD 分别为6.7%、2.0%及2.2%(n =5)。日内及日间精密度分别为2.6%和4.5%。整个分析过程无需有机溶剂。在能力验证样品的分析结果与国家标准方法的结果相吻合的基础上,分析了7件食品样品,获满意结果。%A new method for the rapid determination of cyclamate in foods by capillary zone electrophoresis( CZE)with indirect ultraviolet detection was developed. The separation was carried out with an uncoated fused-silica capillary(75 μm i. d.,total length 80 cm,effective length 70 cm). The separation buffer consisted of 2 mmol / L sodium benzoate,10 mmol / L sodi-um carbonate and 0. 5 mmol / L hexadecyl trimethyl ammonium bromide. The separation voltage was -30 kV and the detection wavelength was 200 nm. The liquid samples could be directly injected after dilution with ultrapure water. The solid samples were first grounded or cut into pieces,and then extracted with ultrapure water. Then,the mixed solution was centrifuged. The supernatant was directly injected or injected after dilution with ultrapure water. The analytes were determined by external calibration. The limits of detection( S / N = 3)and the limits of quantification( S / N = 9 ) were 8. 9 mg / kg and 26. 7 mg / kg,respectively. The linear range between the corrected peak area and the

  4. Dual-channel capillary electrophoresis for simultaneous determination of cations and anions. (United States)

    Opekar, František; Tůma, Petr


    An original electrophoresis apparatus for simultaneous rapid determination of cations and anions has been designed and tested. The separation part of the apparatus consists of two identical fused-silica capillaries, each with a length of 10.5cm and inner diameter of 25μm. The injection space is formed by the crossing of four channels in a plexiglass cross-piece. The capillaries pass through two opposing channels and their injection ends are located opposite one another at a distance of approx. 0.5mm in the centre of the crossing point. The exit ends of the capillaries are placed in vessels containing the background electrolyte in which are immersed the electrodes of a high-voltage source. Contactless conductivity detectors with semi-cylindrical electrodes are located 2cm from the exit ends of the capillaries. The injection part of the apparatus consists of two piezoelectric micro-pumps bringing the solution through another channel in the cross-piece to the injection ends of the capillary. During the injection, the sample is brought through one of them and is injected electrokinetically for a defined time. Then the sample zone is forced out of the injection space by a stream of background electrolyte from the second micro-pump. The timing of the injection process is computer-controlled. Thus the equipment can be considered to constitute electrophoresis in one capillary with injection into its centre. The use of short capillaries and miniature micro-pumps without other mechanical components enabled the construction of the apparatus on a board with dimensions of 20×25cm. The proposed equipment was used to test simultaneous separation of a mixture of cations and anions, NH4(+), K(+), Ca(2+), Mg(2+), Sr(2+), Ba(2+), Cl(-), NO3(-), SO4(2-), ClO3(-) and F(-), in BGE with composition 500mM HAc+20mM Tris+2mM 18-crown-6 (pH 3.3). Baseline separation of all the components was achieved in time less than 1min. Quantification of the content of nitrate nitrogen (determined as

  5. Determination of herbicides paraquat, glyphosate, and aminomethylphosphonic acid in marijuana samples by capillary electrophoresis. (United States)

    Lanaro, Rafael; Costa, José L; Cazenave, Silvia O S; Zanolli-Filho, Luiz A; Tavares, Marina F M; Chasin, Alice A M


    In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15-0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user.

  6. Capillary electrophoresis methods for microRNAs assays: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Eunmi; Song, Eun Joo, E-mail:


    Highlights: • A review of CE analysis of miRNAs. • Summary of developments and applications of CE systems in miRNA studies. • Applications and development of microchip-based CE for rapid analysis of miRNA. - Abstract: MicroRNAs (miRNAs) are short noncoding RNAs that conduct important roles in many cellular processes such as development, proliferation, differentiation, and apoptosis. In particular, circulating miRNAs have been proposed as biomarkers for cancer, diabetes, cardiovascular disease, and other illnesses. Therefore, determination of miRNA expression levels in various biofluids is important for the investigation of biological processes in health and disease and for discovering their potential as new biomarkers and drug targets. Capillary electrophoresis (CE) is emerging as a useful analytical tool for analyzing miRNA because of its simple sample preparation steps and efficient resolution of a diverse size range of compounds. In particular, CE with laser-induced fluorescence detection is a promising and relatively rapidly developing tool with the potential to provide high sensitivity and specificity in the analysis of miRNAs. This paper covers a short overview of the recent developments and applications of CE systems in miRNA studies in biological and biomedical areas.

  7. Quantification of sugars in breakfast cereals using capillary electrophoresis. (United States)

    Toutounji, Michelle R; Van Leeuwen, Matthew P; Oliver, James D; Shrestha, Ashok K; Castignolles, Patrice; Gaborieau, Marianne


    About 80% of the Australian population consumes breakfast cereal (BC) at least five days a week. With high prevalence rates of obesity and other diet-related diseases, improved methods for monitoring sugar levels in breakfast cereals would be useful in nutrition research. The heterogeneity of the complex matrix of BCs can make carbohydrate analysis challenging or necessitate tedious sample preparation leading to potential sugar loss or starch degradation into sugars. A recently established, simple and robust free solution capillary electrophoresis (CE) method was used in a new application to 13 BCs (in Australia) and compared with several established methods for quantification of carbohydrates. Carbohydrates identified in BCs by CE included sucrose, maltose, glucose and fructose. The CE method is simple requiring no sample preparation or derivatization and carbohydrates are detected by direct UV detection. CE was shown to be a more robust and accurate method for measuring carbohydrates than Fehling method, DNS (3,5-dinitrosalicylic acid) assay and HPLC (high performance liquid chromatography).

  8. Capillary electrophoresis-chemiluminescence determination of norfloxacin and prulifloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhongju; Wang Xiaoli [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Qin Weidong [College of Chemistry, Beijing Normal University, Beijing 100875 (China)], E-mail:; Zhao Huichun [College of Chemistry, Beijing Normal University, Beijing 100875 (China)], E-mail:


    A capillary electrophoresis (CE)-chemiluminescence (CL) method for determining norfloxacin (NFLX) and prulifloxacin (PFLX) was developed based on the enhanced CL intensity of the cerium(IV)-sulfite-fluoroquinolone (FQ) reaction sensitized by terbium(III). The separation was conducted in buffer composed of 20 mM sodium citrate, 4 mM citric acid and 10 mM sodium sulfite at pH 6.1. The CL reagent solution consisted of 2 mM cerium(IV), 4 mM terbium(III) and 1.1 mM hydrochloric acid. NFLX and PFLX were baseline separated within 11 min with detection limits (S/N = 3) of 0.057 and 0.084 {mu}g mL{sup -1}, respectively. The maximum intra- and inter-day relative standard deviations (R.S.D.s) of migration time of the analytes were less than 4.0% and 4.2%, respectively. The proposed method was applied to detect NFLX and PFLX in fortified urine sample and the results were comparable to high-performance liquid chromatography (HPLC)-UV method. Moreover, the high selectivity of the CL detection and the high-separation efficiency of CE render the method the potential of quick analyzing fluoroquinolones in real complex matrix.

  9. Electrochemical methods in conjunction with capillary and microchip electrophoresis. (United States)

    Mark, Jonas J P; Scholz, Rebekka; Matysik, Frank-Michael


    Electromigrative techniques such as capillary and microchip electrophoresis (CE and MCE) are inherently associated with various electrochemical phenomena. The electrolytic processes occurring in the buffer reservoirs have to be considered for a proper design of miniaturized electrophoretic systems and a suitable selection of buffer composition. In addition, the control of the electroosmotic flow plays a crucial role for the optimization of CE/MCE separations. Electroanalytical methods have significant importance in the field of detection in conjunction with CE/MCE. At present, amperometric detection and contactless conductivity detection are the predominating electrochemical detection methods for CE/MCE. This paper reviews the most recent trends in the field of electrochemical detection coupled to CE/MCE. The emphasis is on methodical developments and new applications that have been published over the past five years. A rather new way for the implementation of electrochemical methods into CE systems is the concept of electrochemically assisted injection which involves the electrochemical conversions of analytes during the injection step. This approach is particularly attractive in hyphenation to mass spectrometry (MS) as it widens the range of CE-MS applications. An overview of recent developments of electrochemically assisted injection coupled to CE is presented.

  10. Simultaneous quantification of sialyloligosaccharides from human milk by capillary electrophoresis. (United States)

    Bao, Yuanwu; Zhu, Libin; Newburg, David S


    The acidic oligosaccharides of human milk are predominantly sialyloligosaccharides. Pathogens that bind sialic acid-containing glycans on their host mucosal surfaces may be inhibited by human milk sialyloligosaccharides, but testing this hypothesis requires their reliable quantification in milk. Sialyloligosaccharides have been quantified by anion exchange high-performance liquid chromatography (HPLC), reverse- or normal-phase HPLC, and capillary electrophoresis (CE) of fluorescent derivatives; in milk, these oligosaccharides have been analyzed by high pH anion exchange chromatography with pulsed amperometric detection and, in our laboratory, by CE with detection at 205nm. The novel method described here uses a running buffer of aqueous 200mM NaH2PO4 (pH 7.05) containing 100mM sodium dodecyl sulfate (SDS) mixed with 45% (v/v) methanol to baseline resolve 5 oligosaccharides and separate all 12. This allows automated simultaneous quantification of the 12 major sialyloligosaccharides of human milk in a single 35-min run. This method revealed differences in sialyloligosaccharide concentrations between less and more mature milk from the same donors. Individual donors also varied in expression of sialyloligosaccharides in their milk. Thus, the facile quantification of sialyloligosaccharides by this method is suitable for measuring variation in expression of specific sialyloligosaccharides in milk and their relationship to decreased risk of specific diseases in infants.

  11. Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Heidi Adler


    Full Text Available The research was performed to study the simultaneous detection of a homologous series of α, ω-dicarboxylic acids (C2–C10, oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50 μL. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m3.

  12. Synthesis and Characterization of Water-Soluble Carboxymethyl-Cyclodextrin Polymer as Capillary Electrophoresis Chiral Selector

    Institute of Scientific and Technical Information of China (English)


    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.

  13. Applications of on-line weak affinity interactions in free solution capillary electrophoresis

    DEFF Research Database (Denmark)

    Heegaard, Niels H H; Nissen, Mogens H; Chen, David D Y


    The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary...... enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On......-line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities....


    The generic method described here involves typical capillary electrophoresis (CE) techniques, with the addition of cyclodextrin chiral selectors to the electrolyte for enantiomer separation and also, in the case of neutral analytes, the further addition of a micelle forming comp...

  15. Trace analysis of organic ions in ice samples by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Huber, T. [Bern Univ. (Switzerland); Schwikowski, M.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    Capillary electrophoresis was tested as a new analytical method for ice samples. Comparisons to ion chromatography were made concerning accuracy, detection limits, reproducibility, necessary sample volume and time consumption. (author) 1 fig., 3 refs.

  16. DNA sequencing with capillary electrophoresis and single cell analysis with mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Fung, N.


    Since the first demonstration of the laser in the 1960`s, lasers have found numerous applications in analytical chemistry. In this work, two different applications are described, namely, DNA sequencing with capillary gel electrophoresis and single cell analysis with mass spectrometry. Two projects are described in which high-speed DNA separations with capillary gel electrophoresis were demonstrated. In the third project, flow cytometry and mass spectrometry were coupled via a laser vaporization/ionization interface and individual mammalian cells were analyzed. First, DNA Sanger fragments were separated by capillary gel electrophoresis. A separation speed of 20 basepairs per minute was demonstrated with a mixed poly(ethylene oxide) (PEO) sieving solution. In addition, a new capillary wall treatment protocol was developed in which bare (or uncoated) capillaries can be used in DNA sequencing. Second, a temperature programming scheme was used to separate DNA Sanger fragments. Third, flow cytometry and mass spectrometry were coupled with a laser vaporization/ionization interface.

  17. Affinity Probe Capillary Electrophoresis Evaluation of Aptamer Binding to Campylobacter jejuni Bacteria (United States)


    Affinity Probe Capillary Electrophoresis Evaluation of Aptamer Binding to Campylobacter jejuni Bacteria by Dimitra N. Stratis-Cullum, Sun...Aptamer Binding to Campylobacter jejuni Bacteria Dimitra N. Stratis-Cullum, Sun McMasters, and Paul M. Pellegrino Sensors and Electron Devices...To) 2007–2008 4. TITLE AND SUBTITLE Affinity Probe Capillary Electrophoresis Evaluation of Aptamer Binding to Campylobacter jejuni Bacteria 5a

  18. Role of capillary electrophoresis in the fight against doping in sports. (United States)

    Harrison, Christopher R


    At present the role of capillary electrophoresis in the detection of doping agents in athletes is, for the most part, nonexistent. More traditional techniques, namely gas and liquid chromatography with mass spectrometric detection, remain the gold standard of antidoping tests. This Feature will investigate the in-roads that capillary electrophoresis has made, the limitations that the technique suffers from, and where the technique may grow into being a key tool for antidoping analysis.

  19. Zone electrophoresis in an inner-cooling wide-bore electrophoresis system with UV detection. (United States)

    Guo, Yugao; Liu, Danning; Wang, Huaifeng; Yuan, Ruijuan; Bao, James Jianmin


    A novel, high-performance wide-bore electrophoresis (WE) system with inner-cooling has been developed. By introducing the mode of a shell and tube heat exchanger into this system to remove Joule heat generated during electrophoresis, it is feasible to extend electrophoresis from the conventional capillary (i.d. tube (i.d. >1000 microm). The wide tube allows the loading of over 1.0 microL of the sample with an LOD of 3.0 x 10(-4) mg/mL (signal-to-noise ratio, 3:1). Satisfactory separations of model compounds have been achieved on the WE system.

  20. Interactions of helquats with chiral acidic aromatic analytes investigated by partial-filling affinity capillary electrophoresis. (United States)

    Růžička, Martin; Koval, Dušan; Vávra, Jan; Reyes-Gutiérrez, Paul E; Teplý, Filip; Kašička, Václav


    Noncovalent molecular interactions between helquats, a new class of dicationic helical extended diquats, and several chiral acidic aromatic drugs and catalysts have been investigated using partial-filling affinity capillary electrophoresis (PF-ACE). Helquats dissolved at 1mM concentration in the aqueous background electrolyte (40mM Tris, 20mM acetic acid, pH 8.1) were introduced as ligand zones of variable length (0-130mm) into the hydroxypropylcellulose coated fused silica capillary whereas 0.1mM solutions of negatively charged chiral drugs or catalysts (warfarin, ibuprofen, mandelic acid, etodolac, binaphthyl phosphate and 11 other acidic aromatic compounds) were applied as a short analyte zone at the injection capillary end. After application of electric field, analyte and ligand migrated against each other and in case of their interactions, migration time of the analyte was increasing with increasing length of the ligand zone. From the tested compounds, only isomers of those exhibiting helical chirality and/or possessing conjugated aromatic systems were enantioselectively separated through their differential interactions with helquats. Some compounds with conjugated aromatic groups interacted with helquats moderately strongly but non-enantiospecifically. Small compounds with single benzene ring exhibited no or very weak non-enantiospecific interactions. PF-ACE method allowed to determine binding constants of the analyte-helquat complexes from the changes of migration times of the analytes. Binding constants of the weakest complexes of the analytes with helquats were less than 50L/mol, whereas binding constants of the strongest complexes were in the range 1 000-1 400L/mol.

  1. Capillary Electrophoresis Analysis of Cations in Water Samples: An Experiment for the Introductory Laboratory (United States)

    Pursell, Christopher J.; Chandler, Bert; Bushey, Michelle M.


    Capillary electrophoresis is gradually working its way into the undergraduate laboratory curriculum. Typically, experiments utilizing this newer technology have been introduced into analytical or instrumental courses. The authors of this article have introduced an experiment into the introductory laboratory that utilizes capillary electrophoresis…

  2. Capillary electrophoresis as a versatile tool for the bioanalysis of drugs - a review

    NARCIS (Netherlands)

    Boone, CM; Waterval, JCM; Lingeman, H; Ensing, K; Underberg, WJM


    This review article presents an overview of current research on the use of capillary electrophoretic techniques for the analysis of drugs in biological matrices. The principles of capillary electrophoresis and its various separation and detection modes are briefly discussed. Sample pretreatment meth


    Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cmX50 mu m uncoated fused-silica capillary and a 5 mM ammonium a...

  4. Capillary electrophoresis as a tool for the characterization of pentosan nanoparticles. (United States)

    Abdel-Haq, Hanin; Bossù, Elena


    Because capillary zone electrophoresis (CZE) showed higher resolution for highly charged large carbohydrates and complex structures when compared to other chromatographic separation methods, it was chosen for the characterization of nanoparticles (NPs) of pentosan polysulfate (PPS). Thus, using the CZE technique, we developed a reliable, sensitive and rapid protocol that allowed the detection and characterization of PPS NPs. This protocol was able to determine the profile of both the NPs and the species of PPS entrapped into them, and to quantify free and bound PPS showing high reproducibility, acceptable accuracy and a good degree of precision. Moreover, it allowed the evaluation of the size and charge of the NPs. This protocol might be suitable for the characterization of other kinds of NPs also.

  5. Simple determination of a strongly aromatic compound, sotolon, by capillary electrophoresis. (United States)

    Taga, Atsushi; Sato, Atsushi; Suzuki, Kentaro; Takeda, Manami; Kodama, Shuji


    A strongly aromatic compound, sotolon, was assessed by capillary zone electrophoresis within 9 min without specific pre-sample treatment. The calibration curve comprised a straight line with good linearity (R = 0.997) over a relatively wide range of 3.13 to 100 ppm. The precision of this system was excellent with relative standard deviations of 1.39% for migration time and 2.96 % for peak response over 10 repetitions at a concentration of 12.5 ppm. The limit of quantitation and limit of detection values were 3.13 ppm (S/N = 9) and 0.781 ppm (S/N = 3), respectively. Using this system, sotolon was clearly detected from a maple-flavored food additive.

  6. Potential of polyE-323 coated capillaries for capillary electrophoresis of lipids. (United States)

    Martma, Kert; Lindenburg, Petrus W; Habicht, Kaia-Liisa; Vulla, Kaspar; Resik, Kristiin; Kuut, Gunnar; Shimmo, Ruth


    In this note the feasibility of a polyamine-based capillary coating, polyE-323, for capillary electrophoresis (CE) of lipids is explored. PolyE-323 has previously been demonstrated to be suitable to suppress analyte-wall interaction of proteins in CE. However, the full applicability range of polyE-323 has not been exploited yet and it might be useful in the analysis of hydrophobic analytes, such as lipids. In this study, the stability of polyE-323 when using highly organic background electrolytes (BGEs), which are needed to solubilize the lipid analytes, was studied. For this, we used three different lipid samples: sphingomyelin, cardiolipin and a lipid extract from a cell culture. The highly organic BGEs that were used in this study consisted of 94.5% of organic solvents and 5.5% of an aqueous buffer. First, the influence of pure acetonitrile, methanol, propylene carbonate, isopropanol and chloroform on the polyE-323 coating was investigated. Then BGEs were developed and tested, using sphingomyelin and cardiolipin as test analytes in CE-UV experiments. After establishing the best BGEs (in terms of analysis time and repeatability) by CE-UV, sphingomyelin was used as a test analyte to demonstrate that method was also suitable for CE with mass-spectrometry detection (CE-MS). The LOD of sphingomyelin was estimated to be 100 nM and its migration time repeatability was 1.3%. The CE-MS analysis was further applied on a lipid extract obtained from human glioblastoma cells, which resulted in the separation and detection of a multitude of putative lipids. The results of our feasibility study indicate that CE systems based on polyE-323 coated capillaries and highly organic BGEs are promising for fast electromigration-based analysis of lipids.

  7. Optimization of affinity capillary electrophoresis for routine investigations of protein-metal ion interactions. (United States)

    Alhazmi, Hassan A; Deeb, Sami El; Nachbar, Markus; Redweik, Sabine; Albishri, Hassan M; El-Hady, Deia Abd; Wätzig, Hermann


    To facilitate the implementation of affinity capillary electrophoresis into routine binding screening studies of proteins with metal ions, method acceleration, transfer and precision improvement were investigated. Affinity capillary electrophoresis was accelerated by using shorter capillaries, employing lower sample concentrations and smaller injection volumes. Intra- and inter-instrument method transfers were investigated considering the temperature setting of the capillary cooling system. For intra-instrument method transfer, similar results were obtained when transferring a method from a long (62 cm) to a short (31 cm) capillary. The analysis time was reduced from 9 to 4 min. In case of inter-instrument method transfer, interaction results showed small variation on the capillary electrophoresis instrument with inefficient capillary cooling system. Binding measurement precision was enhanced by slightly pushing the sample above the beginning of the capillary. Changing the buffer vials after each 30 runs and employing extra flushing after each 60 subsequent runs further enhanced the precision. The use of 0.1 molar ethylenediaminetetraacetic acid in the rinsing solution successfully desorbs the remaining metal ions from the capillary wall. Excellent precision for apparent mobility ratio measurements was achieved for different protein-metal ion interactions (relative standard deviation of 0.16-0.89%, 15 series, 12 runs for each).

  8. Wheat cultivar discrimination by capillary electrophoresis of gliadins in isoelectric buffers. (United States)

    Capelli, L; Forlani, F; Perini, F; Guerrieri, N; Cerletti, P; Righetti, P G


    A modified method is reported for screening of wheat cultivars: capillary zone electrophoresis of gliadins in isoelectric buffers. Previously published procedures recommended a 100 mM phosphate buffer, supplemented with 0.05% hydroxypropylmethylcellulose and 20% acetonitrile, in uncoated capillaries. Due to the very high conductivity of such a buffer (4.7 mmhos at 25 degrees C) high speed separations (10-12 min analysis time at 800 V/cm) could only be elicited in 20 microm internal diameter (ID) capillaries, at the expense of sensitivity. In the present report, we optimized the background electrolyte as follows: 40 mM aspartic acid (pH=pI=2.77) in the presence of 7 M urea and 0.5% short-chain hydroxyethylcellulose (Mn 27000 Da; apparent pH 3.9 in 7 M urea). As an alternative recipe, the same isoelectric buffer can be supplemented with a mixed organic solvent composed of 4 M urea and 20% acetonitrile (apparent pH 3.66). Due to the much lower conductivity (0.7 mmhos), separations can be carried out at 1000 V/cm in only 10 min, but in larger bore capillaries (50 microm ID), ensuring a five-times higher sensitivity. The gliadin patterns thus obtained are species-specific and allow easy identification of all cultivars tested of both durum and bread wheat. No adsorption of proteins to the silica wall seems to occur and high reproducibility in peak areas and transit times is obtained.

  9. An axial approach to detection in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.


    Our approach involves on-axis illumination of the compounds inside the capillary detection region and is applied to absorbance and fluorescence detection. Absorbance measurements were made by focussing an incident laser beam into one capillary end; by using signals collected over the entire length of analyte band, this enhances the analytical path length of conventional absorbance detection 60x. This instrument offers a 15x improvement in detection limits. Three fluorescence detection experiments are discussed, all of which involve insertion of an optical fiber into capillary. The first uses a high refractive index liquid phase to obtain total internal reflectance along capillary axis, this reducing light scatter. The second uses a charge-coupled device camera for simultaneous imaging of a capillary array (this may be useful in genome sequencing, etc.). The third is a study of fluid motion inside the capillary under pressure-driven and electroosmotic flow. The thesis is divided into four parts. Figs, tabs.

  10. Recent advances in amino acid analysis by capillary electrophoresis. (United States)

    Poinsot, Véréna; Carpéné, Marie-Anne; Bouajila, Jalloul; Gavard, Pierre; Feurer, Bernard; Couderc, François


    This paper describes the most important articles that have been published on amino acid analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138) and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223; Electrophoresis 2010, 31, 105-121). We present new developments in amino acid analysis with CE, which are reported describing the use of lasers or light emitting diodes for fluorescence detection, conductimetry electrochemiluminescence detectors, mass spectrometry applications, and lab-on-a-chip applications using CE. In addition, we describe articles concerning clinical studies and neurochemical applications of these techniques.

  11. Capillary electrophoresis with noncovalently bilayer-coated capillaries for stability study of allergenic proteins in simulated gastrointestinal fluids. (United States)

    Zheng, Chang; Liu, Youping; Zhou, Qiuhong; Di, Xin


    A novel noncovalently bilayer-coated capillary using cationic polymer polybrene (PB) and anionic polymer (sodium 4-styrenesulfonate) (PSS) as coatings was prepared. This PB-PSS coating showed good migration-time reproducibility for proteins and high stability in the range of pH 2-10 and in the presence of 1M NaOH, acetonitrile and methanol. Capillary electrophoresis with PB-PSS coated capillaries was successfully applied to quantitatively investigate the stability of bovine serum albumin, ovomucoid, β-lactoglobulin and lysozyme in simulated gastrointestinal fluids. β-lactoglobulin A and β-lactoglobulin B were both stable in simulated gastric fluid with degradation percentages of 34.3% and 17.2% after 60min of incubation, respectively. Bovine serum albumin, ovomucoid and lysozyme were stable in simulated intestinal fluid with degradation percentages of 17.7%, 23.4% and 22.8% after 60min of incubation, respectively. The superiority of the proposed method over sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and capillary electrophoresis with untreated fused silica capillaries was demonstrated and emphasized.

  12. Simultaneous Determination of FOur Arsenic Additives in Animal Feed by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    BaoguoSun; MiroslavMacka; 等


    Four additives,[4-hydroxy-3-nitrophenylarsonic acid(Roxarsone),4-nitrophenylarsonic acid(4-NPAA),phenylarsonic acid (PAA) and p-aminophenylarsonic acid (p-ASA)] in chicken feed were simultaneously determinated by capillary zone electrophoresis(CZE) with on -line UV-detection.Based on our previous research,the sample extraction,cleanup and detection condition were discussed and optimised,Analytes were extracted with acidic 20% acetonitrile and the cleaned up with C18 SPE before the detection.20mM Carbonate buffer at pH10 was used as electrolyte,A fused silica capillary(48.5cm x75um),18kV working voltage and 200nm detection wavelength were applied for CE detection.Acetonitrile functioned as a modifier to reduce the conductivity of the sample soulution during the CE separation.The sensityvity of the method is sufficient for the routine inspection of Roxarsone in animal feed,The recoveries for all analytes were reasonably good but the precision of the method was poorer than HPLC.

  13. 毛细管区带电泳法同时测定饮料中16种食品添加剂%Determination of sixteen food additives in beverage by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    龙巍然; 岑怡红; 王兴益; 白玉; 刘虎威


    建立了毛细管区带电泳法测定饮料中酸性红92、专利蓝V、荧光素二钠、酸性红1、靛蓝胭脂红、亮黑、丽春红6R、日落黄、苋菜红、柠檬黄等10种人工合成色素和苯甲酸、山梨酸、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯等6种防腐剂的分析方法.考察了缓冲溶液种类、浓度、pH值及运行电压、温度等对分离的影响,确定最佳电泳条件为:未涂层弹性石英毛细管柱(46 cm×50 μm),缓冲溶液为70 mmol/L硼酸(pH=9.5)(含体积分数为4%的乙腈),检测波长220 nm,电泳电压30 kV,进样时间5s,电泳温度25℃.该法用于测定市售饮料样品得到满意结果:在1 ~ 250 mg/L范围内线性关系良好,相关系数不小于0.993 8,回收率在95.8%与108.7%之间.该法简便、准确,能够满足食品添加剂的常规检测要求.%A capillary zone electrophoretic (CZE) method for the separation of ten synthetic colorants such as acid red 92, patent blue V, uranine, acid red 1, indigo carmine, black BN, ponceau 6R, quinoline, amaranth, lemon yellow, and six preservatives including benzoic acid, sorbic acid, methyl paraben, ethyl paraben, propyl paraben, butyl paraben in beverages was developed. The effects of separation voltage, capillary temperature, pH and concentration of running buffer on the separation were investigated. A 46 cm x 50μm uncoated fused silica capillary was used with 70 mmol/L boric acid (pH 9. 5) containing 4% (v/v) acetonitrile as background electrolyte solution. The detection wavelength was set at 220 nm, and the run voltage was 30 kV. The injection time was 5 s at 500 mPa and the temperature was 25℃. The linear relationship between the mass concentration and peak area for each of these analytes was obtained in the concentration range of 1 -250 mg/L, with a correlation coefficient not less than 0. 993 8. The recoveries were between 95. 8% and 108. 7%. The method has

  14. Rapid, Simple and Ultrasensitive Analysis of Paraquat in Drinking Water by Field-Amplified Sample Injection Combined with Pressure-Assisted Capillary Zone Electrophoresis%场放大样品进样-压力辅助毛细管区带电泳测定饮用水中的百草枯

    Institute of Scientific and Technical Information of China (English)

    王明明; 沈菁; 宋婷; 李胜清; 陈浩


    Field-amplified sample injection (FASI) combined with pressure-assisted capillary zone electrophoresis (CZE) was developed for the determination of paraquat in drinking water. High reproducibility in FASI-CZE process could be attained with constant pressure applied at both ends of capillary. Compared with conventional hydrodynamic injection, the enrichment factor of 1174 was achieved for paraquat by FASI. Several parameters including length of water plug, injection time and composition of sample solution were systematically optimized. Linearity, sensitivity, precision and accuracy were investigated to validate the proposed method. The result showed that the calibration curve was linear at the concentration of 1.0 100 (ig/L with a correlation coefficient of 0. 9975. The limit of detection was 0. 039 ng/L (S/N=3). Mean recovery of paraquat was ranged from 78. 4% to 94. 5% with relative standard deviation ranging from 3. 0% to 10. 4%. Finally, the method proposed was applied for the determination of paraquat in real drinking water.

  15. 杜仲炮制前后绿原酸含量的毛细管区带电泳研究%Chlorogenic Acid Content in Crude and Processed Eucommia Ulmoides Oliv. by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    张英; 王淑敏


    Objective To study the content of chlorogenic acid in crude and processed Eucommia ulmoides Oliv. Methods The content was measured by the capillary zone electrophoretic ( CIE ) method. The detection wavelength was set at 327 nm with the separation volt-age of 25 kV,30 mmol/L sodium borate solution(pH=9. 0) was used as the background electrolyte. Results Chlorogenic acid was separated within 12 min. The sample size of chlorogenic acid in the range of 0. 06-0. 30 g/L showed the good linear relation with the peak area. The average recovery rate was 99. 90%,RSD=2. 25%. The content of chlorogenic acid was significantly increased after pro-cessing of Eucommia ulmoides Oliv. Conclusion The processing of Eucommia ulmoides Oliv. has important significance.%目的:对杜仲炮制前后绿原酸成分含量变化进行研究。方法采用高效毛细管电泳法,紫外检测波长327 nm,分离电压25 kV,背景电解质为30 mmol/L硼砂缓冲溶液(pH=9.0)。结果在12 min内绿原酸得到了良好分离,质量浓度在0.06~0.30 g/L范围内与峰面积线性关系良好,平均回收率为99.90%,RSD为2.25%。杜仲炮制后,绿原酸的含量显著增加。结论杜仲炮制具有重要意义。

  16. Determination of preservatives in soft drinks by capillary electrophoresis with ionic liquids as the electrolyte additives. (United States)

    Sun, Bingbing; Qi, Li; Wang, Minglin


    A capillary electrophoresis method for separating preservatives with various ionic liquids as the electrolyte additives has been developed. The performances for separation of the preservatives using five ionic liquids with different anions and different substituted group numbers on imidazole ring were studied. After investigating the influence of the key parameters on the separation (the concentration of ionic liquids, pH, and the concentration of borax), it has been found that the separation efficiency could be improved obviously using the ionic liquids as the electrolyte additives and tested preservatives were baseline separated. The proposed capillary electrophoresis method exhibited favorable quantitative analysis property of the preservatives with good linearity (r(2) = 0.998), repeatability (relative standard deviations ≤ 3.3%) and high recovery (79.4-117.5%). Furthermore, this feasible and efficient capillary electrophoresis method was applied in detecting the preservatives in soft drinks, introducing a new way for assaying the preservatives in food products.

  17. An integrated multiple capillary array electrophoresis system for high-throughput DNA sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Lu, X.


    A capillary array electrophoresis system was chosen to perform DNA sequencing because of several advantages such as rapid heat dissipation, multiplexing capabilities, gel matrix filling simplicity, and the mature nature of the associated manufacturing technologies. There are two major concerns for the multiple capillary systems. One concern is inter-capillary cross-talk, and the other concern is excitation and detection efficiency. Cross-talk is eliminated through proper optical coupling, good focusing and immersing capillary array into index matching fluid. A side-entry excitation scheme with orthogonal detection was established for large capillary array. Two 100 capillary array formats were used for DNA sequencing. One format is cylindrical capillary with 150 {micro}m o.d., 75 {micro}m i.d and the other format is square capillary with 300 {micro}m out edge and 75 {micro}m inner edge. This project is focused on the development of excitation and detection of DNA as well as performing DNA sequencing. The DNA injection schemes are discussed for the cases of single and bundled capillaries. An individual sampling device was designed. The base-calling was performed for a capillary from the capillary array with the accuracy of 98%.

  18. A New Dual-electrode and Multi-channel Electrochemical DetectionSystem for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Bing Yi YANG; Jin Yuan MO; Rong LAI


    A new type of dual-electrode and multi-channel electrochemical detection technology for capillary electrophoresis is described in this paper. Two detectors(the amperometric detector and the conductometric detector)or two conductometric detectors are connected to the same capillary electrophoresis system. The whole system possesses the advantages of the two electrochemical detectors including sparing time,improving the analytical speed and expanding the sample range.The working electrode and detector cell are handled easily.The system was applied to sample detection with satisfactory results.

  19. Congophilicity (Congo red affinity) of different beta2-microglobulin conformations characterized by dye affinity capillary electrophoresis

    DEFF Research Database (Denmark)

    Heegaard, N H; Sen, J W; Nissen, Mogens Holst


    The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red-affinities of......The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red...

  20. Quantitative, small-scale, fluorophore-assisted carbohydrate electrophoresis implemented on a capillary electrophoresis-based DNA sequence analyzer. (United States)

    Murray, Sarah; McKenzie, Marian; Butler, Ruth; Baldwin, Samantha; Sutton, Kevin; Batey, Ian; Timmerman-Vaughan, Gail M


    Fluorophore-assisted carbohydrate electrophoresis (FACE) is an analytical method for characterizing carbohydrate chain length that has been applied to neutral, charged, and N-linked oligosaccharides and that has been implemented using diverse separation platforms, including polyacrylamide gel electrophoresis and capillary electrophoresis. In this article, we describe three substantial improvements to FACE: (i) reducing the amount of starch and APTS required in labeling reactions and systematically analyzing the effect of altering the starch and 8-amino-1,3,6-pyrenetrisulfonic acid (APTS) concentrations on the reproducibility of the FACE peak area distributions; (ii) implementing FACE on a multiple capillary DNA sequencer (an ABI 3130xl), enabling higher throughput than is possible on other separation platforms; and (iii) developing a protocol for producing quantitative output of peak heights and areas using genetic marker analysis software. The results of a designed experiment to determine the effect of decreasing both the starch and fluorophore concentrations on the sensitivity and reproducibility of FACE electrophoregrams are presented. Analysis of the peak area distributions of the FACE electrophoregrams identified the labeling reaction conditions that resulted in the smallest variances in the peak area distributions while retaining strong fluorescence signals from the capillary-based DNA sequencer.

  1. Design and operation of a portable scanner for high performance microchip capillary array electrophoresis. (United States)

    Scherer, James R; Liu, Peng; Mathies, Richard A


    We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ~20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex(®) 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

  2. Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites. (United States)

    Pelcová, Marta; Langmajerová, Monika; Cvingráfová, Eliška; Juřica, Jan; Glatz, Zdeněk


    This study deals with the nonaqueous capillary electrophoretic separation of dextromethorphan and its metabolites using a methanolic background electrolyte. The optimization of separation conditions was performed in terms of the resolution of dextromethorphan and dextrorphan and the effect of separation temperature, voltage, and the characteristics of the background electrolyte were studied. Complete separation of all analytes was achieved in 40 mM ammonium acetate dissolved in methanol. Hydrodynamic injection was performed at 3 kPa for 4 s. The separation voltage was 20 kV accompanied by a low electric current. The ultraviolet detection was performed at 214 nm, the temperature of the capillary was 25°C. These conditions enabled the separation of four analytes plus the internal standard within 9 min. Further, the developed method was validated in terms of linearity, sensitivity, and repeatability. Rat liver perfusate samples were subjected to the nonaqueous capillary electrophoretic method to illustrate its applicability.

  3. Optimization strategies for separation of sulfadiazines using Box-Behnken design by liquid chromatography and capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    GONG Wen-jun; ZHANG Yu-ping; ZHANG Yi-Jun; XU Guang-ri; WEI Xin-jun; LEE Kwang-pill


    Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35 ℃ and 1.0 mL/min, respectively.Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.

  4. A prototypic system of parallel electrophoresis in multiple capillaries coupled with microwell arrays. (United States)

    Su, Jing; Ren, Kangning; Dai, Wen; Zhao, Yihua; Zhou, Jianhua; Wu, Hongkai


    We present a microfluidic system that can be directly coupled with microwell array and perform parallel electrophoresis in multiple capillaries simultaneously. The system is based on an array of glass capillaries, fixed in a polydimethylsiloxane (PDMS) microfluidic scaffold, with one end open for interfacing with microwells. In this capillary array, every two adjacent capillaries act as a pair to be coupled with one microwell; samples in the microwells are introduced and separated by simply applying voltage between two electrodes that are placed at the other ends of capillaries; thus no complicated circuit design is required. We evaluate the performance of this system and perform multiple CE with direct sample introduction from microwell array. Also with this system, we demonstrate the analysis of cellular contents of cells lysed in a microwell array. Our results show that this prototypic system is a promising platform for high-throughput analysis of samples in microwell arrays.

  5. Toward high-throughput monitoring of metallodrug-protein interaction using capillary electrophoresis in chemically modified capillaries. (United States)

    Shmykov, Alexei Y; Filippov, Vladimir N; Foteeva, Lidia S; Keppler, Bernhard K; Timerbaev, Andrei R


    The performance of capillary electrophoresis (CE) operating with a sulfonated capillary for the separation of protein adducts of anticancer ruthenium(III)-based drugs was evaluated. The coated capillary was shown to yield improved resolution of albumin- and transferrin-bound species of ruthenium compared with that attained with the bare fused-silica capillary. The coating also showed an increased reproducibility of migration times and peak areas and allowed reasonably high efficiency separation of analytes (up to 1300 theoretical plates per meter), which display high affinity toward a fused-silica surface. In addition, due to rather high electroosmotic flow (EOF, > 45 x 10(-5)cm(2)V(-1)s(-1)) in the coated capillary, it enabled fast counter-EOF monitoring of albumin and transferrin adducts. This benefit, together with requiring only a short flush with the background electrolyte to have migration times reproducible (at capillary holding promise for CE examination of fast reactions such as those accompanying protein-drug interactions and biotransformations associated with drug delivery via protein binding.

  6. Improving the reproducibility in capillary electrophoresis by incorporating current drift in mobility and peak area calculations

    DEFF Research Database (Denmark)

    Petersen, Nickolaj J.; Hansen, Steen H


    The traditional way of calculating mobility and peak areas in capillary electrophoresis does not take into account the changes in the buffer viscosity at different thermostatic control and that the analytes may accelerate during the individual runs due to Joule heating effects. We present a method...

  7. Study of Oxidation of Glutathione Treated with Hypochlorous Acid by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    Capillary electrophoresis (CE) method was developed for the separation and quantification of reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione sulphonic acid (GSO3H). Baseline separation was obtained within five minutes. The effects of reaction time and molar ratio of hypochlorous acid (HOCI) to GSH on the oxidation of GSH were investigated.


    An analytical method was developed to determine simultaneously, the inorganic anion CrO2-4, and organic aromatic compounds including benzoate, 2-Cl-benzoate, phenol, m-cresol and o-/p-cresol by capillary electrophoresis (CE). Chromate and the aromatics were separated in a relativ...

  9. Disposable pen-shaped capillary gel electrophoresis cartridge for fluorescence detection of bio-molecules (United States)

    Amirkhanian, Varoujan; Tsai, Shou-Kuan


    We introduce a novel and cost-effective capillary gel electrophoresis (CGE) system utilizing disposable pen-shaped gelcartridges for highly efficient, high speed, high throughput fluorescence detection of bio-molecules. The CGE system has been integrated with dual excitation and emission optical-fibers with micro-ball end design for fluorescence detection of bio-molecules separated and detected in a disposable pen-shaped capillary gel electrophoresis cartridge. The high-performance capillary gel electrophoresis (CGE) analyzer has been optimized for glycoprotein analysis type applications. Using commercially available labeling agent such as ANTS (8-aminonapthalene-1,3,6- trisulfonate) as an indicator, the capillary gel electrophoresis-based glycan analyzer provides high detection sensitivity and high resolving power in 2-5 minutes of separations. The system can hold total of 96 samples, which can be automatically analyzed within 4-5 hours. This affordable fiber optic based fluorescence detection system provides fast run times (4 minutes vs. 20 minutes with other CE systems), provides improved peak resolution, good linear dynamic range and reproducible migration times, that can be used in laboratories for high speed glycan (N-glycan) profiling applications. The CGE-based glycan analyzer will significantly increase the pace at which glycoprotein research is performed in the labs, saving hours of preparation time and assuring accurate, consistent and economical results.

  10. Optical sensing in microchip capillary electrophoresis by femtosecond laser written waveguides

    NARCIS (Netherlands)

    Martinez-Vázquez, R.; Osellame, R.; Cretich, M.; Dongre, C.; Hoekstra, H.J.W.M.; Vlekkert, van den H.; Ramponi, R.; Pollnau, M.; Chiari, M.; Cerullo, G.


    Capillary electrophoresis separation in an on-chip integrated microfluidic channel is typically monitored with bulky, bench-top optical excitation/detection instrumentation. Optical waveguides allow confinement and transport of light in the chip directing it to a small volume of the microfluidic cha

  11. Urine Metabolite Profiling of Human Colorectal Cancer by Capillary Electrophoresis Mass Spectrometry Based on MRB

    Directory of Open Access Journals (Sweden)

    Jin-Lian Chen


    (P<0.05. Conclusion. The technique of capillary electrophoresis mass spectrometry based on MRB could reveal the significant metabolic alterations during progression of colorectal cancer, and the method is feasible and may be useful for the early diagnosis of colorectal cancer.

  12. Capillary electrophoresis with laser-induced fluorescence detection for fast and reliable apolipoprotein E genotyping

    NARCIS (Netherlands)

    Somsen, GW; Welten, HTME; Mulder, FP; Swart, CW; Kema, IP; de Jong, GJ


    The use of capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection for the rapid determination of apolipoprotein E (apoE) genotypes was studied. High resolution and sensitive detection of the concerned DNA restriction fragments was achieved using CE buffers with hydroxypropylm

  13. Gold Nanoparticles Enhanced Microchip Capillary Electrophoresis for Detection of Serum Lipoprotein

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; WANG DaXin; CAO Li; CHEN Xia


    @@ We describe here the use of gold nanoparticles (AuNPs) in conjunction with chip-based capillary electrophoresis (CE) to improve the selectivity between lipoprotein fractions and increase the efficiency of the separation.AuNPs were added into the running buffer to manipulate solution and control the electroosmotic flow (EOF).

  14. Feasibility of nonvolatile buffers in capillary electrophoresis-electrospray ionization-mass spectrometry of proteins

    NARCIS (Netherlands)

    Eriksson, Jonas H.C.; Mol, Roelof; Somsen, Govert W.; Hinrichs, Wouter L.J.; Frijlink, Henderik W.; de Jong, Gerhardus J.


    The combination of capillary electrophoresis (CE) and electrospray ionization-mass spectrometry (ESI-MS) via a triaxial interface was studied as a potential means for the characterization of intact proteins. To evaluate the possibility to use a nonvolatile electrolyte for CE, the effect of sodium ph

  15. Capillary electrophoresis of FITC labeled amino acids with laser-induced fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    党福全; 陈义


    FITC labeled amino acids have been separated using a home-huilt capillary electrophoresis with a laserinduced fluorescence detection (CE-LIF) system. Seventeen peaks can now be generated from the twenty common amino acids. The key conditions lie in the optimization of pH, buffer electrolytes and buffer additives.


    The positive ion electrospray mass spectra of the quaternary ammonium salt herbicides paraquat and diquat are examined by on-line separation with capillary electrophoresis (CE) and by direct infusion of the analytes. The analytes are separated by CE in 7-10 min at pH 3.9 in 50% m...

  17. Analysis of recombinant human growth hormone by capillary electrophoresis with bilayer-coated capillaries using UV and MS detection. (United States)

    Catai, Jonatan R; Sastre Toraño, Javier; Jongen, Peter M J M; de Jong, Gerhardus J; Somsen, Govert W


    The characterization of recombinant human growth hormone (rhGH; somatropin) by capillary electrophoresis (CE) with UV-absorbance and mass spectrometric (MS) detection using capillaries noncovalently coated with polybrene (PB) and poly(vinyl sulfonic acid) (PVS) is demonstrated. Compared with bare fused-silica capillaries, PB-PVS coated capillaries yielded more favorable migration-time reproducibilities and higher separation efficiencies. Optimal separation conditions for the bilayer-coated capillaries comprised a background electrolyte (BGE) of 400 mM Tris phosphate (pH 8.5) yielding migration-time R.S.D.s of less than 1.0% and plate numbers above 300,000 for intact rhGH. The protein was also analyzed using the CE method described in the European Pharmacopoeia (Ph. Eur.) monograph. The pharmacopoeial method gave much longer analysis times (22 min versus 8 min), lower resolution and plate numbers, and consecutive shifts in migration time for rhGH, indicating possible interactions between the protein and the inner capillary wall. Due to stable migration times obtained with the coated capillaries, reliable profiling and quantification of rhGH and its byproducts in time was possible. Analysis of thermally degraded rhGH revealed the formation of two main degradation products. CE-mass spectrometry (MS) of this sample, using a PB-PVS coated capillary and a BGE of 75 mM ammonium formate (pH 8.5), suggests that these products are desamido forms of rhGH. Analyses of expired rhGH preparations with CE-UV and CE-MS indicated the presence of both deamidation and oxidation products.

  18. A forensic laboratory tests the Berkeley microfabricated capillary array electrophoresis device. (United States)

    Greenspoon, Susan A; Yeung, Stephanie H I; Johnson, Kelly R; Chu, Wai K; Rhee, Han N; McGuckian, Amy B; Crouse, Cecelia A; Chiesl, Thomas N; Barron, Annelise E; Scherer, James R; Ban, Jeffrey D; Mathies, Richard A


    Miniaturization of capillary electrophoresis onto a microchip for forensic short tandem repeat analysis is the initial step in the process of producing a fully integrated and automated analysis system. A prototype of the Berkeley microfabricated capillary array electrophoresis device was installed at the Virginia Department of Forensic Science for testing. Instrument performance was verified by PowerPlex 16 System profiling of single source, sensitivity series, mixture, and casework samples. Mock sexual assault samples were successfully analyzed using the PowerPlex Y System. Resolution was assessed using the TH01, CSF1PO, TPOX, and Amelogenin loci and demonstrated to be comparable with commercial systems along with the instrument precision. Successful replacement of the Hjerten capillary coating method with a dynamic coating polymer was performed. The accurate and rapid typing of forensic samples demonstrates the successful technology transfer of this device into a practitioner laboratory and its potential for advancing high-throughput forensic typing.

  19. Device for Horizontal Zone Electrophoresis in Free Electrolyte

    CERN Document Server

    Priemyshev, A N; Bozhikov, G A; Alikov, B A; Salamatin, A V; Furyaev, T A; Maslov, O D; Milanov, M V; Dmitriev, S N


    With expansion of area of application of an electromigration method the necessity of modernization of installation for horizontal zone electrophoresis in free electrolyte has appeared. A number of the basic modules was essentially advanced, that has allowed considerably increase reliability and accuracy of received results. The device is completely automated.

  20. A New Denoising Technique for Capillary Electrophoresis Signals

    Institute of Scientific and Technical Information of China (English)

    WANG,Ying(王瑛); MO,Jin-Yuan(莫金垣)


    Capillary electrophorsis (CE) is a powerful analytical tool in chemistry. Thus, it is valuable to solve the denoising of CE signals. A new denoising method called MWDA which employs Mexican Hat wavelet is presented. It is an efficient chemometrics technique and has been applied successfully in processing CE signals. Useful information can be extracted even from signals of S/N = 1. After denoising, the peak positions are unchanged and the relative errors of peak height are less than 3%.

  1. Analytical potential of mid-infrared detection in capillary electrophoresis and liquid chromatography: A review

    Energy Technology Data Exchange (ETDEWEB)

    Kuligowski, Julia; Quintas, Guillermo; Guardia, Miguel de la [Department of Analytical Chemistry, Universitat de Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot (Spain); Lendl, Bernhard, E-mail: [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9-164, A-1060 Vienna (Austria)


    Literature published in the last decade concerning the use of mid-infrared spectrometry as a detection system in separation techniques employing a liquid mobile phase is reviewed. In addition to the continued use of isocratic liquid chromatographic (LC) techniques, advances in chemometric data evaluation techniques now allow the use of gradient techniques on a routine basis, thus significantly broadening the range of possible applications of LC-IR. The general trend towards miniaturized separation systems was also followed for mid-IR detection where two key developments are of special importance. Firstly, concerning on-line detection the advent of micro-fabricated flow-cells with inner volumes of only a few nL for transmission as well as attenuated total reflection measurements enabled on-line mid-IR detection in capillary LC and opened the path for the first successful realization of on-line mid-IR detection in capillary zone electrophoresis as well as micellar electrokinetic chromatography. Secondly, concerning off-line detection the use of micro-flow through dispensers now enables to concentrate eluting analytes on dried spots sized a few tens of micrometers, thus matching the dimensions for sensitive detection by mid-IR microscopy. Finally in an attempt to increase detection sensitivity of on-line mid-IR detection, mid-IR quantum cascade lasers have been used. Applications cover the field of food analysis, environmental analysis and the characterization of explosives among others. Best detection sensitivities for on-line and off-line detection have been achieved in miniaturized systems and are in the order of 50 ng and 2 ng on column, respectively.

  2. Automation and integration of multiplexed on-line sample preparation with capillary electrophoresis for DNA sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Tan, H.


    The purpose of this research is to develop a multiplexed sample processing system in conjunction with multiplexed capillary electrophoresis for high-throughput DNA sequencing. The concept from DNA template to called bases was first demonstrated with a manually operated single capillary system. Later, an automated microfluidic system with 8 channels based on the same principle was successfully constructed. The instrument automatically processes 8 templates through reaction, purification, denaturation, pre-concentration, injection, separation and detection in a parallel fashion. A multiplexed freeze/thaw switching principle and a distribution network were implemented to manage flow direction and sample transportation. Dye-labeled terminator cycle-sequencing reactions are performed in an 8-capillary array in a hot air thermal cycler. Subsequently, the sequencing ladders are directly loaded into a corresponding size-exclusion chromatographic column operated at {approximately} 60 C for purification. On-line denaturation and stacking injection for capillary electrophoresis is simultaneously accomplished at a cross assembly set at {approximately} 70 C. Not only the separation capillary array but also the reaction capillary array and purification columns can be regenerated after every run. DNA sequencing data from this system allow base calling up to 460 bases with accuracy of 98%.

  3. Simultaneous analysis of saturated and unsaturated fatty acids present in pequi fruits by capillary electrophoresis

    Directory of Open Access Journals (Sweden)

    Patrícia M. de Castro Barra


    Full Text Available In the current study, an alternative method has been proposed for simultaneous analysis of palmitic, stearic, oleic, linoleic, and linolenic acids by capillary zone electrophoresis (CZE using indirect detection. The background electrolyte (BGE used for the analysis of these fatty acids (FAs consisted of 15.0 mmol L−1 NaH2PO4/Na2HPO4 at pH 6.86, 4.0 mmol L−1 SDBS, 8.3 mmol L−1 Brij 35, 45% v/v acetonitrile (can, and 2.1% n-octanol. The FAs quantification of FAs was performed using a response factor approach, which provided a high analytical throughput for the real sample. The CZE method, which was applied successfully for the analysis of pequi pulp, has advantages such as short analysis time, absence of lipid fraction extraction and derivatization steps, and no significant difference in the 95% confidence intervals for FA quantification results, compared to the gas chromatography official method (AOCS Ce 1h-05.

  4. Fast analysis of glibenclamide and its impurities: quality by design framework in capillary electrophoresis method development. (United States)

    Furlanetto, Sandra; Orlandini, Serena; Pasquini, Benedetta; Caprini, Claudia; Mura, Paola; Pinzauti, Sergio


    A fast capillary zone electrophoresis method for the simultaneous analysis of glibenclamide and its impurities (I(A) and I(B)) in pharmaceutical dosage forms was fully developed within a quality by design framework. Critical quality attributes were represented by I(A) peak efficiency, critical resolution between glibenclamide and I(B), and analysis time. Experimental design was efficiently used for rapid and systematic method optimization. A 3(5)//16 symmetric screening matrix was chosen for investigation of the five selected critical process parameters throughout the knowledge space, and the results obtained were the basis for the planning of the subsequent response surface study. A Box-Behnken design for three factors allowed the contour plots to be drawn and the design space to be identified by introduction of the concept of probability. The design space corresponded to the multidimensional region where all the critical quality attributes reached the desired values with a degree of probability π ≥ 90%. Under the selected working conditions, the full separation of the analytes was obtained in less than 2 min. A full factorial design simultaneously allowed the design space to be validated and method robustness to be tested. A control strategy was finally implemented by means of a system suitability test. The method was fully validated and was applied to real samples of glibenclamide tablets.

  5. In-capillary approach to eliminate SDS interferences in antibody analysis by capillary electrophoresis coupled to mass spectrometry. (United States)

    Sánchez-Hernández, Laura; Montealegre, Cristina; Kiessig, Steffen; Moritz, Bernd; Neusüß, Christian


    Capillary electrophoresis is an important technique for the characterization of monoclonal antibodies (mAbs), especially in the pharmaceutical context. However, identification is difficult as upscaling and hyphenation of used methods directly to mass spectrometry is often not possible due to separation medium components that are incompatible with MS detection. Here a CE-MS method for the analysis of mAbs is presented analyzing SDS-complexed samples. To obtain narrow and intensive peaks of SDS-treated antibodies, an in-capillary strategy was developed based on the co-injection of positively charged surfactants and methanol as organic solvent. For samples containing 0.2% (v/v) of SDS, recovered MS peak intensities up to 97 and 95% were achieved using cetyltrimethylammonium bromide or benzalkonium chloride, respectively. Successful removal of SDS was shown in neutral coated capillaries but also in a capillary with a positively charged coating applying reversed polarity. The usefulness of this in-capillary strategy was demonstrated also for other proteins and for antibodies dissolved in up to 10% v/v SDS solution, and in other SDS-containing matrices, including the sieving matrix used in a standard CE-SDS method and gel-buffers applied in SDS-PAGE methods. The developed CE-MS approaches enable fast and reproducible characterization of SDS-complexed antibodies.

  6. Development of a capillary electrophoresis-mass spectrometry method using polymer capillaries for metabolomic analysis of yeast. (United States)

    Tanaka, Yoshihide; Higashi, Tetsuji; Rakwal, Randeep; Wakida, Shin-ichi; Iwahashi, Hitoshi


    Metabolomics is an emerging field in analytical biochemistry, and the development of such a method for comprehensive and quantitative analysis of organic acids, carbohydrates, and nucleotides is a necessity in the era of functional genomics. When a concentrated yeast extract was analyzed by CE-MS using a successive multiple ionic-polymer layer (SMIL)-coated capillary, the adsorption of the contaminants on the capillary wall caused severe problems such as no elution, band-broadening, and asymmetric peaks. Therefore, an analytical method for the analysis of anionic metabolites in yeast was developed by pressure-assisted CE using an inert polymer capillary made from poly(ether etherketone) (PEEK) and PTFE. We preferred to use the PEEK over the PTFE capillary in CE-MS due to the easy-to-use PEEK capillary and its high durability. The separation of anionic metabolites was successfully achieved with ammonium hydrogencarbonate/formate buffer (pH 6.0) as the electrolyte solution. The use of 2-propanol washing after every electrophoresis run not only eliminated wall-adsorption phenomena, but allowed for good repeatability to be obtained for migration times in the metabolomic analysis.

  7. A Novel Polybrene/Chondroitin Sulfate C Double Coated Capillary and Its Application in Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    DU,Ying-Xiang(杜迎翔); HONDA,Susumu; TAGA,Atsushi; LIU,Wen-Ying(刘文英); SUZUKI,Shigeo


    A new capillary coated by double polymer, polybrene/chondroitin sulfate C (P/CC), was developed using a simple procedure. The P/CC double coated capillary showed long lifetime,strong chemical stability and good reproducibility. It endured during more than 100 replicated analyses and was also tolerant to HCl (1 mol/L), NaOH (0.01 mol/L), CH3OH and CH3CN. The P/CC double coated capillary can be applied to basic drug analyses. The adsorption of basic drugs to the capillary wall was suppressed and the peak tailing greatly decreased. The use of the P/CC double coated capillary allowed excelent separation of the enantiomers of some basic drugs by using chondroitin sulfate C as the chiral selector, ami the peak symmetry of basic drugs was further improved under these conditions.

  8. Comparison of three modifications of fused-silica capillaries and untreated capillaries for protein profiling of maize extracts by capillary electrophoresis. (United States)

    Pobozy, Ewa; Sentkowska, Aleksandra; Piskor, Anna


    In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused-silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω-iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated. It was found that for zeins separation, the most stable and efficient was the capillary coated with polyacrylamide. Finally, the usefulness of these methods was studied for the differentiation of zein fraction in transgenic and nontransgenic maize. Zeins extracted from maize standards containing 0 and 5% m/m genetic modification were successfully separated, but slight differences were observed in terms of the zein content. Albumin and globulin fractions were analyzed with the use of unmodified fused-silica capillary with borate buffer pH 9 and the capillary coated with polyacrylamide with phosphate buffer pH 3. In the albumin fraction, additional peaks were found in genetically modified samples.

  9. Capillary electrophoresis: Biotechnology for separation of DNA and chromosomes (United States)

    Williams, George O., Jr.


    Electrophoresis has been used for the separation of particles, ions, and molecules for a number of years. The technology for separation and detection of the results has many applications in the life sciences. One of the major goals of the scientific community is to separate DNA molecules and intact chromosomes based upon their different lengths or number of base pairs. This may be achieved by using some of the commercially available and widely used methods, but these processes require a considerable amount of time. The challenge is to achieve separation of intact chromosomes in a short time, preferably in a matter of minutes.

  10. Self-assembly of cellulose nanoparticles as electrolyte additive for capillary electrophoresis separation. (United States)

    Huang, Dihui; Yang, Qin; Jin, Shanxia; Deng, Qianchun; Zhou, Ping


    In this work, a new cellulose derivative, octadecyl modified quaternized cellulose (ODMQC), was synthesized and used as additive in the background electrolyte for capillary electrophoresis. The derivative bearing hydrophobic groups and hydrophilic groups can self-assemble into a stable nano-scaled micelle structure in aqueous solution. When ODMQC was added in running buffer, the capillaries were shown to generate applicable anodal EOF over the investigated range of pH 3.0-12.0. Due to the lack of UV active groups, the ODMQC did not disturb the UV detection. It is shown that ODMQC-added capillaries allow the separation of basic proteins by reducing their adsorption onto the capillary wall. Also, the addition of ODMQC provides adequate separation of aromatic acids with low pKa values and improved separation of sulfa drugs. Moreover, it is demonstrated that the addition of ODMQC can incorporate an additional reversed-phase mechanism that improves the separation of neutral analytes.

  11. Application of capillary electrophoresis to the development and evaluation of aptamer affinity probes (United States)

    Sooter, Letha J.; McMasters, Sun; Stratis-Cullum, Dimitra N.


    Nucleic acid aptamers can exhibit high binding affinities for a wide variety of targets and have received much attention as molecular recognition elements for enhanced biosensor performance. These aptamers recognize target molecules through a combination of conformational dependent non-covalent interactions in aqueous media which can be investigated using capillary electrophoresis-based methods. In this paper we report on the results of our studies of the relative binding affinity of Campylobacter jejuni aptamers using a capillary electrophoretic immunoassay. Our results show preferential binding to C. jejuni over other common food pathogen bacteria. Capillary electrophoresis can also be used to develop new aptamer recognition elements using an in vitro selection process known as systematic evolution of ligand by exponential enrichment (SELEX). Recently, this process has been adapted to use capillary electrophoresis in an attempt to shorten the overall selection process. This smart selection of nucleic acid aptamers from a large diversity of a combinatorial DNA library is under optimization for the development of aptamers which bind to Army-relevant targets. This paper will include a discussion of the establishment of CE-SELEX methods for the future development of smart aptamer probes.

  12. Evaluation of interactions between RAW264.7 macrophages and small molecules by capillary electrophoresis. (United States)

    Wang, Feng-Qin; Li, Qiao-Qiao; Zhang, Qian; Wang, Yin-Zhen; Hu, Yuan-Jia; Li, Peng; Wan, Jian-Bo; Yang, Feng-Qing; Xia, Zhi-Ning


    In this study, the affinity interactions between RAW 264.7 macrophages and three small molecules including naringin, oleuropein and paeoniflorin were evaluated by affinity capillary electrophoresis (ACE), partial filling affinity capillary electrophoresis (PFACE) and frontal analysis capillary electrophoresis (FACE), respectively. The result indicated that ACE (varying concentrations of cell suspension were filled in the capillary as receptor) may not be suitable for the evaluation of interactions between cell and small molecules due to the high viscosity of cell suspension; PFACE can qualitatively evaluate the interaction, but the difference in viscosity between RAW264.7 suspension and buffer effects on the liner relationship between filling length and injection time, which makes the calculation of binding constant difficult. Furthermore, based on the PFACE results, naringin showed stronger interaction with macrophages than the other two molecules; taking advantage of the aggregation phenomenon of cell induced by electric field, FACE was successfully used to determine the stoichiometry (n = 5×10(9) ) and binding constant (Kb = 1×10(4) L/mol) of the interaction between RAW264.7 and naringin.

  13. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis. (United States)

    Creamer, Jessica S; Oborny, Nathan J; Lunte, Susan M


    The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis.

  14. Analytical study of Joule heating effects on electrokinetic transportation in capillary electrophoresis. (United States)

    Xuan, Xiangchun; Li, Dongqing


    Electric fields are often used to transport fluids (by electroosmosis) and separate charged samples (by electrophoresis) in microfluidic devices. However, there exists inevitable Joule heating when electric currents are passing through electrolyte solutions. Joule heating not only increases the fluid temperature, but also produces temperature gradients in cross-stream and axial directions. These temperature effects make fluid properties non-uniform, and hence alter the applied electric potential field and the flow field. The mass species transport is also influenced. In this paper we develop an analytical model to study Joule heating effects on the transport of heat, electricity, momentum and mass species in capillary-based electrophoresis. Close-form formulae are derived for the temperature, applied electrical potential, velocity, and pressure fields at steady state, and the transient concentration field as well. Also available are the compact formulae for the electric current and the volume flow rate through the capillary. It is shown that, due to the thermal end effect, sharp temperature drops appear close to capillary ends, where sharp rises of electric field are required to meet the current continuity. In order to satisfy the mass continuity, pressure gradients have to be induced along the capillary. The resultant curved fluid velocity profile and the increase of molecular diffusion both contribute to the dispersion of samples. However, Joule heating effects enhance the sample transport velocity, reducing the analysis time in capillary electrophoretic separations.

  15. Application of plasma-polymerized films for isoelectric focusing of proteins in a capillary electrophoresis chip. (United States)

    Tsai, Shuo-Wen; Loughran, Michael; Hiratsuka, Atsunori; Yano, Kazuyoshi; Karube, Isao


    The first use of plasma polymerization technique to modify the surface of a glass chip for capillary isoelectric focusing (cIEF) of different proteins is reported. The electrophoresis separation channel was machined in Tempax glass chips with length 70 mm, 300 microm width and 100 microm depth. Acetonitrile and hexamethyldisiloxane monomers were used for plasma polymerization. In each case 100 nm plasma polymer films were coated onto the chip surface to reduce protein wall adsorption and minimize the electroosmotic flow. Applied voltages of 1000 V, 2000 V and 3000 V were used to separate mixtures of cytochrome c (pI 9.6), hemoglobin (pI 7.0) and phycocyanin (pI 4.65). Reproducible isoelectric focusing of each pI marker protein was observed in different coated capillaries at increasing concentration 2.22-5 microg microL(-1). Modification of the glass capillary with hydrophobic HMDS plasma polymerized films enabled rapid cIEF within 3 min. The separation efficiency of cytochrome c and phycocyanin in both acrylamide and HMDS coated capillaries corresponded to a plate number of 19600 which compares favourably with capillary electrophoresis of neurotransmitters with amperometric detection.

  16. Evaluation of migration behaviour of therapeutic peptide hormones in capillary electrophoresis using polybrene-coated capillaries. (United States)

    Aptisa, Ghiulendan; Benavente, Fernando; Sanz-Nebot, Victoria; Chirila, Elisabeta; Barbosa, José


    Modelling electrophoretic mobility as a function of pH can be simultaneously used for determination of ionization constants and for rapid selection of the optimum pH for separation of mixtures of the modelled compounds. In this work, equations describing the effect of pH on electrophoretic behaviour were used to investigate migration of a series of polyprotic amphoteric peptide hormones between pH 2 and 12 in polybrene-coated capillaries. Polybrene (hexadimethrin bromide) is a polymer composed of quaternary amines that is strongly adsorbed by the fused-silica inner surface, preventing undesired interactions between the peptides and the inner capillary wall. In polybrene-coated capillaries the separation voltage must be reversed, because of the anodic electroosmotic flow promoted by the polycationic polymer attached to the inner capillary wall. The possibility of using polybrene-coated capillaries for determination of accurate ionization constants has been evaluated and the optimum pH for separation of a mixture of the peptide hormones studied has been selected. Advantages and disadvantages of using bare fused-silica and polybrene-coated capillaries for these purposes are discussed.

  17. Determination of aggregation thresholds of UV absorbing anionic surfactants by frontal analysis continuous capillary electrophoresis. (United States)

    Le Saux, Thomas; Varenne, Anne; Gareil, Pierre


    Aggregation of anionic surfactants was investigated by frontal analysis continuous capillary electrophoresis (FACCE), a method involving the continuous electrokinetic introduction of the surfactant sample into the separation capillary. This process results in a partial separation of the monomeric and aggregated forms without perturbing the monomer-aggregate equilibrium. The critical micelle concentration (CMC) can then be easily derived from the height of the firstly detected migration front, corresponding to the monomeric form. This approach is exemplified with octyl and dodecylbenzenesulfonates and compared with conductimetry and surface tension measurements. FACCE turns out to be an effective method for the determination of CMC and intermediate aggregation phenomena with very small sample and short time requirements.

  18. Optimizing separation conditions of 19 polycyclic aromatic hydrocarbons by cyclodextrin-modified capillary electrophoresis and applications to edible oils. (United States)

    Ferey, Ludivine; Delaunay, Nathalie; Rutledge, Douglas N; Cordella, Christophe B Y; This, Hervé; Huertas, Alain; Raoul, Yann; Gareil, Pierre


    For the first time, the separation of 19 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants in environmental and food samples by the United States Environmental Protection Agency (US-EPA) and the European Food Safety Authority was developed in cyclodextrin (CD)-modified capillary zone electrophoresis with laser-induced fluorescence detection (excitation wavelength: 325 nm). The use of a dual CD system, involving a mixture of one neutral CD and one anionic CD, enabled to reach unique selectivity. As solutes were separated based on their differential partitioning between the two CDs, the CD relative concentrations were investigated to optimize selectivity. Separation of 19 PAHs with enhanced resolutions as compared with previous studies on the 16 US-EPA PAHs and efficiencies superior to 1.5 × 10(5) were achieved in 15 min using 10mM sulfobutyl ether-β-CD and 20mM methyl-β-CD. The use of an internal standard (umbelliferone) with appropriate electrolyte and sample compositions, rinse sequences and sample vial material resulted in a significant improvement in method repeatability. Typical RSD variations for 6 successive experiments were between 0.8% and 1.7% for peak migration times and between 1.2% and 4.9% for normalized corrected peak areas. LOQs in the low µg/L range were obtained. For the first time in capillary electrophoresis, applications to real vegetable oil extracts were successfully carried out using the separation method developed here.

  19. Characterization of in vitro modified human very low-density lipoprotein particles and phospholipids by capillary electrophoresis. (United States)

    Liu, Yi-Ning; Shu, Ting-Yu; Xie, Huai-Guang; Lai, Wei-Ting; Liao, Yi-Han; Su, Mei-Yu; Lin, You-Sian; Chen, Yen-Yi; Lin, Yi-Jyun; Chong, Chin-Pong; Liu, Mine-Yine


    A simple capillary zone electrophoresis (CZE) method was used to characterize human very low-density lipoprotein (VLDL) particles for four healthy donors. One major peak was observed for native, in vitro oxidized and glycated VLDL particles. The effective mobilities and peak areas of the capillary electrophoresis (CE) profiles showed good reproducibility and precision. The mobility of the oxidized VLDL peak was higher than that of the native VLDL. The mobility of the glycated VLDL peak was similar to that of the native VLDL. Phospholipids isolated from VLDL particles were analyzed by our recently developed micellar electrokinetic chromatography (MEKC) with a high-salt stacking method. At absorbance 200 nm, the native VLDL phospholipids showed a major peak and a minor peak for each donor. For oxidized VLDL phospholipids, the area of the major peak reduced for three donors, possibly due to phospholipid decomposition. For glycated VLDL phospholipids, the peak mobilities were more positive than native VLDL phospholipids for two donors, possibly due to phospholipid-linked advanced glycation end products (AGEs). Very interestingly, at absorbance 234 nm, the major peak of oxidized VLDL phospholipids was resolved as two peaks for each donor, possibly due to conjugated dienes formed upon oxidation.

  20. Characterization of in Vitro Modified Human Very Low-Density Lipoprotein Particles and Phospholipids by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Chin-Pong Chong


    Full Text Available A simple capillary zone electrophoresis (CZE method was used to characterize human very low-density lipoprotein (VLDL particles for four healthy donors. One major peak was observed for native, in vitro oxidized and glycated VLDL particles. The effective mobilities and peak areas of the capillary electrophoresis (CE profiles showed good reproducibility and precision. The mobility of the oxidized VLDL peak was higher than that of the native VLDL. The mobility of the glycated VLDL peak was similar to that of the native VLDL. Phospholipids isolated from VLDL particles were analyzed by our recently developed micellar electrokinetic chromatography (MEKC with a high-salt stacking method. At absorbance 200 nm, the native VLDL phospholipids showed a major peak and a minor peak for each donor. For oxidized VLDL phospholipids, the area of the major peak reduced for three donors, possibly due to phospholipid decomposition. For glycated VLDL phospholipids, the peak mobilities were more positive than native VLDL phospholipids for two donors, possibly due to phospholipid-linked advanced glycation end products (AGEs. Very interestingly, at absorbance 234 nm, the major peak of oxidized VLDL phospholipids was resolved as two peaks for each donor, possibly due to conjugated dienes formed upon oxidation.

  1. Single-strand conformation polymorphism analysis using capillary array electrophoresis for large-scale mutation detection. (United States)

    Larsen, Lars Allan; Jespersgaard, Cathrine; Andersen, Paal Skytt


    This protocol describes capillary array electrophoresis single-strand conformation polymorphism (CAE-SSCP), a screening method for detection of unknown and previously identified mutations. The method detects 98% of mutations in a sample material and can be applied to any organism where the goal is to determine genetic variation. This protocol describes how to screen for mutations in 192 singleplex or up to 768 multiplex samples over 3 days. The protocol is based on the principle of sequence-specific mobility of single-stranded DNA in a native polymer, and covers all stages in the procedure, from initial DNA purification to final CAE-SSCP data analysis, as follows: DNA is purified, followed by PCR amplification using fluorescent primers. After PCR amplification, double-stranded DNA is heat-denatured to separate the strands and subsequently cooled on ice to avoid reannealing. Finally, samples are analyzed by capillary electrophoresis and appropriate analysis software.

  2. A New Immunoassay Method by Capillary Electrophoresis with Enhanced Chemiluminescence Detection

    Institute of Scientific and Technical Information of China (English)

    Jiao Ning WANG; Ji Cun REN


    This paper described a new immunoassay method by capillary electrophoresis with enhanced chemiluminescence (CL) detection system based on luminol-hydrogen peroxide reaction catalyzed by horseradish peroxides (HRP). Using para-iodophenol as a CL enhancer, the detection limit of about 1×10-12 mol/L for HRP was achieved, which corresponded to 1.32×10-5U/mL. In optimal conditions, the free HRP-labeled CA125 antibody (Ab*) and the bound enzyme-labeled complex (Ab*-Ag) were well separated by capillary electrophoresis within 4 min.The assay was successfully used to determine the contents of CA125 in human sera, which were associated with ovarian cancer, and the recoveries of the standard addition experiments were 96 to109 %.

  3. Ultrafast Capillary Electrophoresis Isolation of DNA Aptamer for the PCR Amplification-Based Small Analyte Sensing (United States)

    Fiore, Emmanuelle; Dausse, Eric; Dubouchaud, Hervé; Peyrin, Eric; Ravelet, Corinne


    Here, we report a new homogeneous DNA amplification-based aptamer assay for small analyte sensing. The aptamer of adenosine chosen as the model analyte was split into two fragments able to assemble in the presence of target. Primers were introduced at extremities of one fragment in order to generate the amplifiable DNA component. The amount of amplifiable fragment was quantifiable by Real-Time Polymerase Chain Reaction (RT-PCR) amplification and directly reliable on adenosine concentration. This approach combines the very high separation efficiency and the homogeneous format (without immobilization) of capillary electrophoresis and the sensitivity of real time PCR amplification. An ultrafast isolation of target-bound split aptamer (60 s) was developed by designing a capillary electrophoresis input/ouput scheme. Such method was successfully applied to the determination of adenosine with a LOD of 1 µM.

  4. Demonstrating Chemical and Analytical Concepts in the Undergraduate Laboratory Using Capillary Electrophoresis and Micellar Electrokinetic Chromatography (United States)

    Palmer, Christopher P.


    This paper describes instrumental analysis laboratory exercises that utilize capillary electrophoresis and micellar electrokinetic chromatography to demonstrate several analytical and chemical principles. Alkyl parabens (4-hydroxy alkyl benzoates), which are common ingredients in cosmetic formulations, are separated by capillary electrophoresis. The electrophoretic mobilities of the parabens can be explained on the basis of their relative size. 3-Hydroxy ethylbenzoate is also separated to demonstrate the effect of substituent position on the acid dissociation constant and the effect this has on electrophoretic mobility. Homologous series of alkyl benzoates and alkyl phthalates (common plasticizers) are separated by micellar electrokinetic chromatography at four surfactant concentrations. This exercise demonstrates the separation mechanism of micellar electrokinetic chromatography, the concept of chromatographic phase ratio, and the concepts of micelle formation. A photodiode array detector is used in both exercises to demonstrate the advantages and limitations of the detector and to demonstrate the effect of pH and substituent position on the spectra of the analytes.

  5. Nonaqueous capillary electrophoresis of imatinib mesylate and related substances. (United States)

    Ye, Lei; Huang, Yifei; Li, Jian; Xiang, Guangya; Xu, Li


    In the present study, nonaqueous capillary electrophoretic separation of imatinib mesylate (IM) and related substances, N-(5-amino-2-methylphenyl)-4-(3-pyridyl)-2-pyrimidinamine (PYA), N-(4-methyl-3-(4-(pyridin-3-yl)pyrimidin-2-ylamino)phenyl)-4-((piperazin-1-yl)methyl) benzamide (NDI) and 4-chloromethyl-N-(4-methyl-3-((4-(pyridin-3-yl) pyrimidin-2-yl) amino) phenyl) benzamide (CPB) was developed. The influential factors affecting separation, including type and concentration of the electrolyte, applied voltage, and buffer modifier were investigated. Baseline separation of the studied analytes was obtained using a buffer of 50 mM Tris and 50 mM methanesulfonic acid in methanol at a apparent pH (pH*) of 1.65. To enhance the sensitivity, large-volume sample stacking was employed for online concentration. The strongest analytical signal with a suitable separation was achieved when the injection time was 100 s. The linearity ranges of PYA and NDI were 0.100-2.50 μg mL(-1), and that of CPB was 0.125-2.50 μg mL(-1), with good coefficients (r(2) > 0.9948). The relative standard deviations of intra- and interday were satisfactory. Under the optimized conditions, seven batches of the synthesized samples were analyzed and CPB was detected in two batches. Owing to its simplicity, effectiveness, and low price, the developed method is promising for quality control of IM.

  6. Chiral Separation of Ibuprofen and Terbutaline by Nonaqueous Capillary Electrophoresis with Conductance Detection

    Institute of Scientific and Technical Information of China (English)


    In the nonaqueous N,N-dimethylformamide medium, the chiral drugs ibuprofen and terbutaline were successfully separated with sulfonyl-β-cyclodextrin(s-β-CD) as the chiral selector by capillary electrophoresis with conductance detection. The comparison of the effects of three CDS(β-CD, diethylic-β-CD, sulfonyl-β-CD) on the chiral separation was made and the resolution mechanism was proposed.

  7. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis (United States)

    Jung, Wooseok; Barrett, Matthew; Brooks, Carla; Rivera, Andrew; Birdsell, Dawn N.; Wagner, David M.; Zenhausern, Frederic


    We present a new elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis. The valve functions include metering to capture a designated volume of biological sample into a polymerase chain reaction (PCR) chamber, sealing to preserve the sample during PCR cycling, and transfer of the PCR-products and on-chip formamide post-processing for the analysis of DNA fragments by capillary gel electrophoresis. This new valve differs from prior art polydimethylsiloxane (PDMS) valves in that the valve is not actuated externally by air-pressure or vacuum so that it simplifies a DNA analysis system by eliminating the need for an air-pressure or vacuum source, and off-cartridge solenoid valves, control circuit boards and software. Instead, the new valve is actuated by a thermal cycling peltier assembly integrated within the hardware instrument that tightly comes in contact with a microfluidic cartridge for thermal activation during PCR, so that it spontaneously closes the valve without an additional actuator system. The valve has bumps in the designated locations so that it has a self-alignment that does not require precise alignment of a valve actuator. Moreover, the thickness of the new valve is around 600 μm with an additional bump height of 400 μm so that it is easy to handle and very feasible to fabricate by injection molding compared to other PDMS valves whose thicknesses are around 30-100 μm. The new valve provided over 95% of metering performance in filling the fixed volume of the PCR chamber, preserved over 97% of the sample volume during PCR, and showed very comparable capillary electrophoresis peak heights to the benchtop assay tube controls with very consistent transfer volume of the PCR-product and on-chip formamide. The new valve can perform a core function for integrated nucleic acid analysis by capillary electrophoresis.

  8. Capillary electrophoresis and mass spectrometry for screening of metabolic disorders in newborns. (United States)

    Senk, Petr; Kozák, Libor; Foret, Frantisek


    Clinical analyses always represent a challenge for the sensitivity and selectivity of the analytical techniques. Of the most critical are the techniques required for the quick determination of the disease state and application of the proper treatment in newborns. This short critical review overviews the present state of the art of the use of mass spectrometry and capillary electrophoresis for screening of metabolic disorders in newborns.

  9. DNA Separation by Capillary Electrophoresis with Ultraviolet Detection using Mixed Synthetic Polymers

    Institute of Scientific and Technical Information of China (English)

    Qian WANG; Xu XU


    The mixtures of two polymers, poly (N,N-dimethylacrylamide) (PDMA) and polyvinylpyrrolidone (PVP) were synthesized and used as the separation medium for double-stranded and single-stranded DNA fragments by capillary electrophoresis with UV detector. On optimal conditions, 2%w/v PDMA ( 2%w/v PVP can be used to separate the doublet 123/124bp in pBR322/Hae III Markers.

  10. Characterization of Nanoparticles by Capillary Electrophoresis and Trapping of Nanoparticles in Microfluidics Device (United States)


    from Sigma-Aldrich Canada Ltd. (Oakville, ON). 2-(N-Morpholino)ethane sulphonic acid (MES) was from ICN Biomedical Inc. (Aurora, OH). BODIPY 493/503...sized biological detection systems. To this end the physico-chemical properties of a variety of NPs were examined using capillary electrophoresis...valuable tool in NP research. The physico-chemical properties of NPs have critical effects on their behaviour in bio-analytical devices. Thus NPs

  11. A covalent modified hydrophilic capillary for enhanced capillary electrophoresis of biopolymers

    Institute of Scientific and Technical Information of China (English)

    Lian Guo Shan; Xue Yu; Yin Mao Wei; Xiao Hui Zheng; Jian Bin Zheng


    δ-Gluconolactone was covalently coupled to aminopropyl derivatized capillary,which created hydrophilic brushes on the inner wall of the capillary.The coated capillary was shown to generate a stable electroosmotic flow(EOF)in the investigated pH range of 2.0-9.0 and to suppress effectively the adsorption of proteins.And it enabled separation of some biopolymer mixtures including basic proteins,DNA and tryptic digested bovine serum albumin(BSA)within 15 min with efficiencies up to 450,000 plates/m.The intra-and inter-day reproducibility of the coating referring to the retention times of proteins were satisfactory with mean relative standard deviations(R.S.D.)of 0.8 and 1.7%,respectively.

  12. Determination of Enantiomeric Purity of n-Pyrrolidinyl Phenylpropanol by Capillary Electrophoresis Using b-Cyclodextrin Polymer as Chiral Selector

    Institute of Scientific and Technical Information of China (English)


    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%.

  13. A Novel Protocol to Analyze Short- and Long-Chain Fatty Acids Using Nonaqueous Microchip Capillary Electrophoresis (United States)

    Cable, M. L.; Stockton, A. M.; Mora, Maria F; Willis, P. A.


    We propose a new protocol to identify and quantify both short- and long-chain saturated fatty acids in samples of astrobiological interest using non-aqueous microchip capillary electrophoresis (micronNACE) with laser induced fluorescence (LIF).


    The instability of sulfonylureas in solution in methanol has led us to a kinetic study of methanolysis of two sulfonylureas using capillary electrophoresis. In a preliminary experiment solutions of the seven compounds, bensulfuron methyl, sulfometuron methyl, nicosulfuron, chlori...

  15. Steroid determination in fish plasma using capillary electrophoresis (United States)

    Bykova, L.; Archer-Hartmann, S. A.; Holland, L.A.; Iwanowicz, L.R.; Blazer, V.S.


    A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone, estrone, 11-ketotestosterone, ethynyl estradiol, and 17β-estradiol. Based on screening of plasma, the performance of the analytical method was determined for 17α,20β-dihydroxypregn-4-en-3-one, testosterone, 11-ketotestosterone, and 17β-estradiol. The within-day reproducibility in migration time for these four steroids in aqueous samples was ≤2%. Steroid quantification was accomplished using a calibration curve obtained with external standards. Plasma samples from fish collected from the Choptank and Severn Rivers, Maryland, USA, stored for up to one year were extracted with ethyl acetate and then further processed with anion exchange and hydrophobic solid phase extraction cartridges. The recovery of testosterone and 17β-estradiol from yellow perch plasma was 84 and 85%, respectively. Endogenous levels of testosterone ranged from 0.9 to 44 ng/ml, and when detected 17α,20β-dihydroxypregn-4-en-3-one ranged from 5 to 34 ng/ml. The reported values for testosterone correlated well with the immunoassay technique. Endogenous concentrations of 17β-estradiol were ≤1.7 ng/ml. 11-Ketotestosterone was not quantified because of a suspected interferant. Higher levels of 17α,20β-dihydroxypregn-4-en-3-one were found in male and female fish in which 17β-estradiol was not detected. Monitoring multiple steroids can provide insight into hormonal fluctuations in fish.

  16. Charge Effect on the Quantum Dots-Peptide Self-Assembly Using Fluorescence Coupled Capillary Electrophoresis. (United States)

    Wang, Jianhao; Li, Jingyan; Teng, Yiwan; Bi, Yanhua; Hu, Wei; Li, Jinchen; Wang, Cheli; Qiu, Lin; Jiang, Pengju


    We present a molecular characterization of metal-affinity driven self-assembly between CdSe-ZnS quantum dots and a series of hexahistidine peptides with different charges. In particular, we uti- lized fluorescence coupled capillary electrophoresis to test the self-assembly process of quantum dots with peptides in solution. Four peptides with different charges can be efficiently separated by fluorescence coupled capillary electrophoresis. The migration time appeared to be influenced by the charges of the peptide. In addition, the kinetics of self-assembly process of quantum dots with one of the peptides manifested a bi-phasic kinetics followed by a saturating stage. This work revealed that there exist two types of binding sites on the surface of quantum dots for peptide 1: one type termed "high priority" binding site and a "low priority" site which is occupied after the first binding sites are fully occupied. The total self-assembly process finishes in solution within 80 s. Our work represents the systematic investigation of the details of self-assembly kinetics utilizing high-resolution fluorescence coupled capillary electrophoresis. The charge effect of peptide coating quantum dots provides a new way of preparing bioprobes.

  17. Development of novel separation techniques for biological samples in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Huan -Tsung [Iowa State Univ., Ames, IA (United States)


    This dissertation includes three different topics: general introduction of capillary electrophoresis (CE); gradient in CE and CE in biological separations; and capillary gel electrophoresis (CGE) for DNA separation. Factors such as temperature, viscosity, pH, and the surface of capillary walls affecting the separation performance are demonstrated. A pH gradient between 3.0 and 5.2 is useful to improve the resolution among eight different organic acids. A flow gradient due to the change in the concentration of surfactant, which is able to coat to the capillary wall to change the flow rate and its direction, is also shown as a good way to improve the resolution for organic compounds. A temperature gradient caused by joule heat is shown by voltage programming to enhance the resolution and shorten the separation time for several phenolic compounds. The author also shows that self-regulating dynamic control of electroosmotic flow in CE by simply running separation in different concentrations of surfactant has less matrix effect on the separation performance. One of the most important demonstrations in this dissertation is that the author proposes on-column reaction which gives several advantages including the use of a small amount of sample, low risk of contamination, and time saving and kinetic features. The author uses this idea with laser induced fluorescence (LIF) as a detection mode to detect an on-column digestion of sub-ng of protein. This technique also is applied to single cell analysis in the group.

  18. Restriction Enzyme Pattern Analysis of Mycobacteria DNA by Capillary Electrophoresis with Laser-induced Fluorescence Detection

    Institute of Scientific and Technical Information of China (English)

    Li Yuanqian; Wang Guoqing; Mi Jianping; Zhou Ying; Zeng Hongyan; Zhang Chaowu


    A new method for rapidly detecting restriction enzyme patterns of Mycobacterium DNA using capillary electrophoresis with laser-induced fluorescence detection (CE-LIFD)was developed.Polymerase chain reaction was used to amplify a 439-bp fragment of a 65,000-kDa(Mr)heat shock protein gene(hsp65)of Mycobacterium.After digesting amplification products by BstEII and HaeIII,patterns of enzyme cleavage products were detected by both CE-LIFD and agarose gel electrophoresis(AGE),respectively.Experimental parameters of CE were optimized.Restriction enzyme patterns of Mycobacterium DNA were detected in optimum electrophoresis conditions:a coated capillary column with a length of 50 cm and an internal diameter of 100 μm,an electrophoresis buffer of 45 mmol/1 Tris-boric acid-ethylenediaminetetraacetic acid,and a running voltage of 11 kV.The restriction enzyme patterns for eight species of mycobacteria were studied.Relative standard deviations of the relative migration times of DNA segments were<3.6%.Compared with AGE,CE is more outstanding in resolution and detection time,and it can be applied as a more effective means to DNA restriction enzyme pattern analysis.

  19. On-capillary derivatisation as an approach to enhancing sensitivity in capillary electrophoresis. (United States)

    Glatz, Zdeněk


    Separation technologies play an important role in revealing biological processes at various omic levels, in pharmacological and clinical research. In this context, CE is a strong candidate for analyses of samples with rapidly increasing complexity. Even though CE is well known for its many advantages in this regard, the sensitivity of CE analyses is insufficient for many applications. Accordingly, there are generally three main options for enhancing the sensitivity of CE analyses - using special detection techniques, using sample pre-concentration and derivatisation. Derivatisation is often the method of choice for many laboratories, since it is simple and provides several advantages such as small sample volume demand and the possibility of automation. Although it can be performed in different ways depending on where the reaction takes place, this article reviews one of the simplest and at the same time most useful approaches on-capillary derivatisation. Even if in many cases the use of on-capillary derivatisation alone is enough to improve the detection sensitivity, on other occasions it needs to be employed in combination with the other above-mentioned strategies. After a simple discussion of derivatisation in general, special attention is focused on the on-capillary approach and methodologies available for on-capillary reactant mixing. Its applications in various fields are also described.

  20. Application of isotachophoresis in commercial capillary electrophoresis instrument using C(4) D and UV detection. (United States)

    Koczka, Péter I; Bodor, Róbert; Masár, Marián; Gáspár, Attila


    In this work, we tested the applicability of a commercial CE instrument (Agilent) for capillary ITP (CITP). The fused silica capillaries were flushed with PVP solution before each sample injection to suppress the EOF. As a dual-detection mode, commercial capacitively coupled contactless conductivity detection and ultraviolet detectors were applied. The experiments showed that the detection gap of the capacitively coupled contactless conductivity detection limits the achievable LOD and the separation resolution when the analyte CITP zones are very narrow, therefore long (120 cm) CE capillary was used and it was largely filled with the sample solution. CITP analyses of several real samples (leather extract, red wine, juice, and fizzy drink) have been demonstrated. In peak mode of CITP when the zone of a chromophore analyte is positioned between nonchromophore zones, excellent sensitivity (in submicromolar concentration range) could be achieved by ultraviolet detection. The hazardous chromate in low concentration was determined in the aqueous extract of tanned leather.

  1. Very fast capillary electrophoresis with electrochemical detection for high-throughput analysis using short, vertically aligned capillaries. (United States)

    Mark, Jonas Josef Peter; Piccinelli, Paolo; Matysik, Frank-Michael


    A method for conducting fast and efficient capillary electrophoresis (CE) based on short separation capillaries in vertical alignment was developed. The strategy enables for high-throughput analysis from small sample vials (low microliter to nanoliter range). The system consists of a lab-made miniaturized autosampling unit and an amperometric end-column detection (AD) cell. The device enables a throughput of up to 200 separations per hour. CE-AD separations of a dye model system in capillaries of only 4 to 7.5 cm length with inner diameters (ID) of 10 or 15 μm were carried out under conditions of very high electric field strengths (up to 3.0 kV/cm) with high separation efficiency (half peak widths below 0.2 s) in less than 3.5 s migration time. A non-aqueous background electrolyte, consisting of 10 mM ammonium acetate and 1 M acetic acid in acetonitrile, was used. The practical suitability of the system was evaluated by applying it to the determination of dyes in overhead projector pens.

  2. Determination of Aniline and Its Derivatives in Environmental Water by Capillary Electrophoresis with On-Line Concentration

    Directory of Open Access Journals (Sweden)

    Jianzhi Sun


    Full Text Available This paper describes a simple, sensitive and environmentally benign method for the direct determination of aniline and its derivatives in environmental water samples by capillary zone electrophoresis (CZE with field-enhanced sample injection. The parameters that influenced the enhancement and separation efficiencies were investigated. Surprisingly, under the optimized conditions, two linear ranges for the calibration plot, 1–50 ng/mL and 50–1000 ng/mL (R > 0.998, were obtained. The detection limit was in the range of 0.29–0.43 ng/mL. To eliminate the effect of the real sample matrix on the stacking efficiency, the standard addition method was applied to the analysis of water samples from local rivers.

  3. Critical aspects of analysis of Micrococcus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary electrophoresis. (United States)

    Hoerr, Verena; Stich, August; Holzgrabe, Ulrike


    Within the frame of our study we investigated Microccocus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary zone electrophoresis (CZE). They form chains and clusters on a different scale, which can be reflected in the electropherograms. A low buffer concentration of Tris-borate and Na2EDTA containing a polymeric matrix of 0.0125% poly(ethylene) oxide (PEO) was used. Key factors were the standardization and optimization of CE conditions, buffer solution, and pretreatment of bacterial samples, which are not transferable to different bacterial strains, in general. The different compositions of the cell wall of on the one hand Gram-positive (M. luteus) and Gram-negative (N. cinerea) cocci and on the other hand Gram-negative, rod-shaped bacteria (P. fluorescens), are probably responsible for the different pretreatment conditions.

  4. Capillary electrophoresis of intact basic proteins using noncovalently triple-layer coated capillaries. (United States)

    Haselberg, Rob; de Jong, Gerhardus J; Somsen, Govert W


    The usefulness of a noncovalent, positively charged capillary coating for the efficient analysis of intact basic proteins with CE was studied. Capillaries were coated by subsequent flushing with solutions of 10% w/v Polybrene (PB), 3% w/v dextran sulfate (DS), and again 10% w/v PB. Coating characterization studies showed that stable coatings could be produced which exhibited a pH-independent and highly reproducible EOF. The PB-DS-PB coating was evaluated with Tris phosphate BGEs of various pH using the four basic model proteins: alpha-chymotrypsinogen A, ribonuclease A, cytochrome c, and lysozyme. Typical migration time RSDs for the proteins were less than 0.85%, and apparent plate numbers were above 125,000 using a capillary length of 40 cm. The high separation efficiency allowed detection of several minor impurities in the model proteins. Using a BGE of medium pH, the CE system with triple-layer coating appeared to be useful for the repeatable profiling of recombinant humanized mouse monoclonal immunoglobulin G(1) showing a characteristic pattern of glycoforms. The CE system was also applied to the characterization of two llama antibodies, which were produced in Saccharomyces cerevisiae, revealing the presence of a side product in one of the antibodies. The high migration time stability allowed the reliable determination of antibody-antigen binding by monitoring migration time shifts. Finally, the feasibility of using the PB-DS-PB coated capillaries for CE with mass spectrometric detection was shown by the characterization of the impure llama antibody sample.

  5. A novel covalent coupling method for coating of capillaries with liposomes in capillary electrophoresis. (United States)

    Mei, Jie; Xu, Jian-Rong; Xiao, Yu-Xiu; Liao, Xiao-Yan; Qiu, Guo-Fu; Feng, Yu-Qi


    A novel covalent coupling method for coating of capillaries with liposomes has been developed, which includes three steps: (i) epoxy-diol coating, (ii) activation with 2,2,2-trifluoroethanesulfonyl chloride, and (iii) liposome coupling. The coating conditions, such as the reaction time and temperature of liposome coupling, the content of dimyristoylphosphatidylethanolamine in liposomes, were optimized. Vesicles were visualized on the inner silica wall as confirmed by atomic force microscopy. The effectiveness of the coating was demonstrated by investigating the effect of pH of BGE on EOF and separating neutral compounds. The intra- and inter-capillary variations in EOF are 4.02% RSD (n=30) and 6.72% RSD (n=4) respectively, and the coated capillaries can be used to perform analysis at least for one month without any performance deterioration when stored at 4 degrees C. A set of drugs with diverse structures was applied into the developed liposome-coated CE. The normalized capacity factor (K) was introduced to quantitatively evaluate drug-membrane interactions. The relationship between log K and the fraction dose absorbed in humans (Fa%) shows that the liposome-coated CE can be utilized for in vitro prediction of Fa% of drugs that follow the transcellular passive transport route.

  6. A semipermanent coating for preventing protein adsorption at physiological pH in kinetic capillary electrophoresis. (United States)

    de Jong, Stephanie; Epelbaum, Nicolas; Liyanage, Ruchi; Krylov, Sergey N


    Protein adsorption to the inner capillary wall hinders the use of kinetic capillary electrophoresis (KCE) when studying noncovalent protein-ligand interactions. Permanent and dynamic capillary coatings have been previously reported to alleviate much of the problems associated with protein adsorption. The characteristic limitations associated with permanent and dynamic coatings motivated us to look at a third type of coating - semipermanent. Here, we demonstrate that a semipermanent capillary coating, designed by Lucy and co-workers, comprised of dioctadecyldimethylammonium bromide (DODAB) and polyoxyethylene (POE) stearate, greatly reduces protein adsorption at physiological pH - a necessary requirement for KCE. The coating (i) does not inhibit protein-DNA complex formation, (ii) prevents the adsorption of the analytes, and (iii) supports an electoosmotic flow required for many applications of KCE. The coating was tested in three physiological buffers using a well-known DNA aptamer and four proteins that severely bind to bare silica capillaries as standards. For every protein, a condition was found under which the semipermanent coating effectively suppresses protein adhesion. While no coating can completely prevent the adsorption of all proteins, our findings suggest that the DODAB/POE stearate coating can have a broad impact on CE at large, as it prevents the absorption of several well studied, highly adhesive proteins at physiological pH.

  7. Optimization of capillary array electrophoresis single-strand conformation polymorphism analysis for routine molecular diagnostics. (United States)

    Jespersgaard, Cathrine; Larsen, Lars Allan; Baba, Shingo; Kukita, Yoji; Tahira, Tomoko; Christiansen, Michael; Vuust, Jens; Hayashi, Kenshi; Andersen, Paal Skytt


    Mutation screening is widely used for molecular diagnostics of inherited disorders. Furthermore, it is anticipated that the present and future identification of genetic risk factors for complex disorders will increase the need for high-throughput mutation screening technologies. Capillary array electrophoresis (CAE) SSCP analysis is a low-cost, automated method with a high throughput and high reproducibility. Thus, the method fulfills many of the demands to be met for application in routine molecular diagnostics. However, the need for performing the electrophoresis at three temperatures between 18 degrees C and 35 degrees C for achievement of high sensitivity is a disadvantage of the method. Using a panel of 185 mutant samples, we have analyzed the effect of sample purification, sample medium and separation matrix on the sensitivity of CAE-SSCP analysis to optimize the method for molecular diagnostic use. We observed different effects from sample purification and sample medium at different electrophoresis temperatures, probably reflecting the complex interplay between sequence composition, electrophoresis conditions and sensitivity in SSCP analysis. The effect on assay sensitivity from three different polymers was tested using a single electrophoresis temperature of 27 degrees C. The data suggest that a sensitivity of 98-99% can be obtained using a 10% long chain poly-N,N-dimethylacrylamide polymer.

  8. Developments in coupled solid-phase extraction-capillary electrophoresis 2013-2015. (United States)

    Ramautar, Rawi; Somsen, Govert W; de Jong, Gerhardus J


    An overview of the design and application of coupled solid-phase extraction-capillary electrophoresis (SPE-CE) systems reported in the literature between July 2013 and June 2015 is provided in this paper. The present article is a continuation of our previous review papers on this topic which covered the time period 2000-2013 (Electrophoresis 2008, 29, 108-128; Electrophoresis 2010, 31, 44-54; Electrophoresis 2012, 33, 243-250; Electrophoresis 2014, 35, 128-137). The use of in-line and on-line SPE-CE approaches is treated and outlined in this review. Recent advancements, such as, for example, the use of aptamers as affinity material for in-line SPE-CE, the use of a bead string design for in-line fritless SPE-CE, and new interfacing techniques for the on-line coupling of SPE to CE, are outlined. Selected examples demonstrate the applicability of the coupled SPE-CE systems for biomedical, pharmaceutical, environmental, and food studies. A complete overview of the recent SPE-CE studies is given in table format, providing information on sample type, SPE sorbent, coupling mode, detection mode, and LOD. Finally, some general conclusions and perspectives are provided.

  9. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2014-2016). (United States)

    Breadmore, Michael C; Wuethrich, Alain; Li, Feng; Phung, Sui Ching; Kalsoom, Umme; Cabot, Joan M; Tehranirokh, Masoomeh; Shallan, Aliaa I; Abdul Keyon, Aemi S; See, Hong Heng; Dawod, Mohamed; Quirino, Joselito P


    One of the most cited limitations of capillary (and microchip) electrophoresis is the poor sensitivity. This review continues to update this series of biennial reviews, first published in Electrophoresis in 2007, on developments in the field of on-line/in-line concentration methods in capillaries and microchips, covering the period July 2014-June 2016. It includes developments in the field of stacking, covering all methods from field amplified sample stacking and large volume sample stacking, through to isotachophoresis, dynamic pH junction, and sweeping. Attention is also given to on-line or in-line extraction methods that have been used for electrophoresis.

  10. Free zone electrophoresis simulation of static column electrophoresis in microgravity on shuttle flight STS-3 (United States)

    Todd, P. W.; Hjerten, S.


    Experiments were designed to replicate, as closely as possible in 1-G, the conditions of the STS-3 red blood cell (RBC) experiments. Free zone electrophoresis was the method of choice, since it minimizes the role of gravity in cell migration. The physical conditions of the STS-3 experiments were used, and human and rabbit RBC's fixed by the same method were the test particles. The effects of cell concentration, electroosmotic mobility, and sample composition were tested in order to seek explanations for the STS-3 results and to provide data on cell concentration effects for future zero-G separation on the continuous-flow zero-G electrophoretics separator.

  11. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    DEFF Research Database (Denmark)

    Franzen, Ulrik; Østergaard, Jesper


    Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary...... electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability...... of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization...

  12. Raman spectroscopy and capillary electrophoresis applied to forensic colour inkjet printer inks analysis. (United States)

    Król, Małgorzata; Karoly, Agnes; Kościelniak, Paweł


    Forensic laboratories are increasingly engaged in the examination of fraudulent documents, and what is important, in many cases these are inkjet-printed documents. That is why systematic approaches to inkjet printer inks comparison and identification have been carried out by both non-destructive and destructive methods. In this study, micro-Raman spectroscopy and capillary electrophoresis (CE) were applied to the analysis of colour inkjet printer inks. Micro-Raman spectroscopy was used to study the chemical composition of colour inks in situ on a paper surface. It helps to characterize and differentiate inkjet inks, and can be used to create a spectra database of inks taken from different cartridge brands and cartridge numbers. Capillary electrophoresis in micellar electrophoretic capillary chromatography mode was applied to separate colour and colourless components of inks, enabling group identification of those components which occur in a sufficient concentration (giving intensive peaks). Finally, on the basis of the obtained results, differentiation of the analysed inks was performed. Twenty-three samples of inkjet printer inks were examined and the discriminating power (DP) values for both presented methods were established in the routine work of experts during the result interpretation step. DP was found to be 94.0% (Raman) and 95.6% (CE) when all the analysed ink samples were taken into account, and it was 96.7% (Raman) and 98.4% (CE), when only cartridges with different index numbers were considered.

  13. Chiral separation of benzoporphyrin derivative mono- and diacids by laser induced fluorescence-capillary electrophoresis. (United States)

    Peng, Xuejun; Sternberg, Ethan; Dolphin, David


    A method for the separation of benzoporphyrin derivative mono- and diacid (BPDMA, BPDDA) enantiomers by laser induced fluorescence-capillary electrophoresis (LIF-CE) has been developed. By using 300 mM borate buffer, pH 9.2, 25 mM sodium cholate and 10% acetronitrile as electrolyte, +10 kV electrokinetic sampling injection of 2 s and an applied +20 kV voltage across the ends of a 37 cm capillary (30 cm to the detector, 50 microm ID), all six BPD stereoisomers were baseline-separated within 20 min. Formation constants, free electrophoretic and complexation mobilities with borate and cholate were determined based on dynamic complexation capillary electrophoresis theory. The BPD enantiomers can be quantitatively determined in the range of 10(-2)-10(-5) mg mL(-1). The correlation coefficients (r2) of the least-squares linear regression analysis of the BPD enantiomers are in the range of 0.9914-0.9997. Their limits of detection are 2.18-3.5 x 10(-3) mg mL(-1). The relative standard deviations for the separation were 2.90-4.64% (n = 10). In comparison with high-performance liquid chromatography (HPLC), CE has better resolution and efficiency. This separation method was successfully applied to the BPD enantiomers obtained from a matrix of bovine serum and from liposomally formulated material as well as from studies with rat, dog and human microsomes.

  14. Quantitative on-line concentration for capillary electrophoresis with inkjet sample introduction technique. (United States)

    Rang, Ying; Zeng, Hulie; Nakajima, Hizuru; Kato, Shungo; Uchiyama, Katsumi


    A quantitative sample introduction method based upon inkjet injection was applied to capillary electrophoresis coupled with stacking and sweeping on-line concentration techniques. Methylxanthines were used as model compounds for the proof-of-concept of the method. The volume of injected sample could be easily manipulated by controlling the number of ejected droplets in the injection procedure. Under optimized conditions, a linear relationship between the ejected droplet number and peak area was obtained when the droplet number introduced into the capillary was less than 100. Under optimized quantitative on-line concentration conditions, the limits of detection for theobromine, caffeine, and theophylline were 1.0, 2.0, and 1.0 μM, respectively. The inkjet injection system was evaluated by comparing it with conventional injection methods. The electropherogram of the inkjet injection mode was the same as that for hydrodynamic injection mode, and no sample discrimination was observed compared with the electrokinetic injection mode. The established method was applied to the determination of methylxanthines in bottled green tea. The recoveries of theobromine, caffeine, and theophylline were 94.1, 110.6, and 86.8%, respectively. We conclude that proposed method can be used for quantitative concentration for capillary electrophoresis, thus resulting in an improved accuracy.

  15. Two-dimensional separation of ionic species by hyphenation of capillary ion chromatography × capillary electrophoresis-mass spectrometry. (United States)

    Beutner, Andrea; Kochmann, Sven; Mark, Jonas Josef Peter; Matysik, Frank-Michael


    The separation of complex mixtures such as biological or environmental samples requires high peak capacities, which cannot be established with a single separation technique. Therefore, multidimensional systems are in demand. In this work, we present the hyphenation of the two most important (orthogonal) techniques in ion analysis, namely, ion chromatography (IC) and capillary electrophoresis (CE), in combination with mass spectrometry. A modulator was developed ensuring a well-controlled coupling of IC and CE separations. Proof-of-concept measurements were performed using a model system consisting of nucleotides and cyclic nucleotides. The data are presented in a multidimensional contour plot. Analyte stacking in the CE separation could be exploited on the basis of the fact that the suppressed IC effluent is pure water.

  16. Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis%食品中柠檬黄铝色淀和日落黄铝色淀的毛细管区带电泳分析

    Institute of Scientific and Technical Information of China (English)

    张一丁; 常翠兰; 郭启雷; 曹红; 白玉; 刘虎威


    A novel analytical method for tartrazine aluminum lake and sunset yellow aluminum lake using capillary zone electrophoresis(CZE)was studied. The pigments contained in the col-or lakes were successfully separated from the aluminum matrix in the pre-treatment process, which included the following steps:dissolve the color lakes in 0. 1 mol / LH2 SO4 ,adjust the pH of the solution to 5. 0,then mix it with the solution of EDTA·2Na and heat it in a water bath, then use polyamide powder as the stationary phase of solid phase extraction to separate the pig-ments from the solution,and finally elute the pigments with 0. 1 mol / L NaOH. The CZE condi-tions systematically optimized for tartrazine aluminum lake were:48. 50cm of a fused silica capillary with 40. 00cm effective length and 50 μm i. d.,the temperature controlled at 20. 0 ℃ , 29. 0kV applied,HPO 2-4 -PO 3-4(0. 015 mol / L,pH 11. 45)solution as running buffer,detection at 263 nm. The conditions for sunset yellow aluminum lake were:the same capillary and tempera-ture,25. 0kV applied,HPO 2-4 -PO 3-4(0. 025mol / L,pH 11. 45)solution as running buffer,detec-tion at 240 nm. The limits of detection were 0. 26 mg / L and 0. 27mg / L,and the linear ranges were 0. 53 - 1. 3 × 102 mg / L and 0. 54 - 1. 4 × 102mg / L for tartrazine aluminum lake and sunset yellow aluminum lake,respectively. The RSDs were 4. 3% and 5. 7%(run to run,n = 6),5. 6%and 6. 0%(day to day,n = 6)for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. Further developments for this method could make it a routinely used method ana-lyzing color lakes in foods.%发展了一种新的采用毛细管区带电泳分析柠檬黄铝色淀和日落黄铝色淀的方法。通过前处理步骤成功实现了铝色淀中铝基质与色素的分离。利用石英毛细管柱(48.50 cm(有效长度40.00 cm)×50μm),分别针对柠檬黄铝色淀和日落黄铝色淀进行了电泳条件的优化,并得到最优分离结果。所建

  17. High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Gang [Iowa State Univ., Ames, IA (United States)


    The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations (RSD) after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. The authors further improved the fluorescence detection by step laser scanning. A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluorescein is 3 x 10-11 M (S/N = 3) for 5-mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  18. High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Gang Xue


    The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations (RSD) after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. The authors further improved the fluorescence detection by step laser scanning. A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluorescein is 3 x 10{sup -11} M (S/N = 3) for 5-mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  19. Optimization of separation and detection schemes for DNA with pulsed field slab gel and capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, D.A.


    The purpose of the Human Genome Project is outlined followed by a discussion of electrophoresis in slab gels and capillaries and its application to deoxyribonucleic acid (DNA). Techniques used to modify electroosmotic flow in capillaries are addressed. Several separation and detection schemes for DNA via gel and capillary electrophoresis are described. Emphasis is placed on the elucidation of DNA fragment size in real time and shortening separation times to approximate real time monitoring. The migration of DNA fragment bands through a slab gel can be monitored by UV absorption at 254 nm and imaged by a charge coupled device (CCD) camera. Background correction and immediate viewing of band positions to interactively change the field program in pulsed-field gel electrophoresis are possible throughout the separation. The use of absorption removes the need for staining or radioisotope labeling thereby simplifying sample preparation and reducing hazardous waste generation. This leaves the DNA in its native state and further analysis can be performed without de-staining. The optimization of several parameters considerably reduces total analysis time. DNA from 2 kb to 850 kb can be separated in 3 hours on a 7 cm gel with interactive control of the pulse time, which is 10 times faster than the use of a constant field program. The separation of {Phi}X174RF DNA-HaeIII fragments is studied in a 0.5% methyl cellulose polymer solution as a function of temperature and applied voltage. The migration times decreased with both increasing temperature and increasing field strength, as expected. The relative migration rates of the fragments do not change with temperature but are affected by the applied field. Conditions were established for the separation of the 271/281 bp fragments, even without the addition of intercalating agents. At 700 V/cm and 20{degrees}C, all fragments are separated in less than 4 minutes with an average plate number of 2.5 million per meter.

  20. Automated dual capillary electrophoresis system with hydrodynamic injection for the concurrent determination of cations and anions

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Thi Thanh Thuy; Mai, Thanh Duc [University of Basel, Department of Chemistry, Spitalstrasse 51, Basel 4056 (Switzerland); Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Nguyen, Thanh Dam [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Sáiz, Jorge [Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering – University of Alcalá, Ctra. Madrid-Barcelona km 33.6, Alcalá de Henares, Madrid 28871 (Spain); Pham, Hung Viet, E-mail: [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Hauser, Peter C., E-mail: [University of Basel, Department of Chemistry, Spitalstrasse 51, Basel 4056 (Switzerland)


    Highlights: • Concurrent determination of cations and anions was carried out by electrophoretic separation. • Optimized conditions for each class of analystes was possible by using separate capillaries. • Simultaneous hydrodynamic injection was carried out. • Pneumatic actuation was used for flushing and sample handling. • The denitrification of drinking water was successfully demonstrated. - Abstract: The capillary electrophoresis instrument developed for the concurrent determination of cations and anions features two separate capillaries and individual detectors to allow independent optimization for each group of ions. The capillaries are joined in a common injector block. The sample is drawn into the injector with a small membrane pump and automated simultaneous injection into both capillaries is achieved by pressurization of the fluid with compressed air. Flushing of the injector and of the capillaries with the background electrolyte is also carried out automatically by the same means. The buffer consisted of 12 mM histidine and 2 mM 18-crown-6 adjusted to pH 4 with acetic acid and was suitable for the contactless conductivity detection employed. The system was optimized for the determination of cationic NH{sub 4}{sup +} and anionic NO{sub 3}{sup −} and NO{sub 2}{sup −}, and linear calibration curves from about 20 μM up to about 1.5 mM were obtained for these ions. In a test run over 8 h, the reproducibility for the peak areas was within ±7%. For demonstration, the instrument was successfully applied to the concurrent monitoring of the concentrations of the three ions during the biological removal of ammonium from contaminated groundwater in a sequencing batch reactor, where NO{sub 3}{sup −} and NO{sub 2}{sup −} are formed as intermediate products.

  1. Recent advances on the use of cyclodextrins in the chiral analysis of drugs by capillary electrophoresis. (United States)

    Saz, J M; Marina, M L


    The most recent advances on the use of cyclodextrins as chiral selectors in capillary electrophoresis for the enantioseparation of drugs are reviewed in this article. The types of cyclodextrins employed and the resolutions achieved are discussed. The use of dual chiral systems, modified capillaries, non-aqueous media or microfluidic devices is also included and the mechanisms for enantioseparation of drugs and the inversion of the enantiomer migration order are studied. The most relevant applications developed to carry out the quantitation of chiral drugs, to assess the enantiomeric purity of pharmaceutical formulations, to study their metabolism or to achieve criminalistic or forensic investigations are described. Articles published in the last six years (period from 2010 to 2015) are considered.

  2. 12-Channel Peltier array temperature control unit for single molecule enzymology studies using capillary electrophoresis. (United States)

    Craig, Douglas B; Reinfelds, Gundars; Henderson, Anna


    Capillary electrophoresis has been used to demonstrate that individual molecules of a given enzyme support different catalytic rates. In order to determine how rate varies with temperature, and determine activation energies for individual β-galactosidase molecules, a 12-channel Peltier array temperature control device was constructed where the temperature of each cell was separately controlled. This array was used to control the temperature of the central 30 cm of a 50 cm long capillary, producing a temperature gradient along its length. Continuous flow single β-galactosidase molecule assays were performed allowing measurement of the catalytic rates at different temperatures. Arrhenius plots were produced and the distribution of activation energies for individual β-galactosidase molecules was found to be 56 ± 10 kJ/mol with a range of 34-72 kJ/mol.

  3. Effect of polyamines on the separation of ovalbumin glycoforms by capillary electrophoresis. (United States)

    Legaz, M E; Pedrosa, M M


    The successful separation of ovalbumin (M(r) 45,000; pI 4.7) glycoforms by capillary electrophoresis in an uncoated fused-silica capillary with different buffer additives is reported. The optimum conditions for obtaining the resolution of glycoforms were 25 mM borate (pH 9.0) containing 0.87 mM spermidine or 0.14 mM spermine. The effects of different concentrations of putrescine, cadaverine, spermidine, spermine and some monoamines or diamines are compared in terms of selectivity factors of ovalbumin peaks. Addition of sodium dodecyl sulfate at a concentration below the critical micelle concentration increased the resolution between the three main peaks of ovalbumin but did not permit their microheterogeneity to be expressed.

  4. Separation and characterisation of detonation nanodiamond by capillary zone electrophoresis. (United States)

    Duffy, Emer; Mitev, Dimitar P; Nesterenko, Pavel N; Kazarian, Artaches A; Paull, Brett


    A new method for the characterisation of purified detonation nanodiamond (DND) using CZE has been developed. The influence of BGE conditions on electrophoretic mobility, peak shape and particle aggregation was investigated, with resultant observations supported by zeta potential approximations and particle size measurements. Sodium tetraborate (pH 9.3), Tris (pH 9.3) and sodium phosphate (pH 7) were used in studying the BGE concentration effect on a commercial source of chemically stabilised DND. The BGE concentration had a strong effect on the stability of DND in suspension. The formation of aggregates of various sizes was observed as BGE concentration increased. The effect of pH on the electromigration of DND was examined using sodium phosphate (pH 8 and 10). The CZE method was subsequently applied to four different DND samples, which had undergone different routes of purification following detonation synthesis. Each sample produced a unique electrophoretic peak or profile in sodium tetraborate buffer (pH 9.3), such that the actual separation of DND samples from different sources could be achieved.

  5. Sensitive Method for Enantioseparation of Rivastigmine with Highly Sulfated Cyclodextrin as Chiral Selector by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-Yan; XU Xing-Xiang; HU Zhi-De; KANG Jing-Wu


    A sensitive method for enantioseparation of a basic drug rivastigmine and determination of its optical impurity by capillary electrophoresis with highly sulfatedβ-cyclodextrin (HS-β-CD) as the chiral selector is described. In general, enantioseparation of basic chiral compounds is carried out in acidic condition (pH 2.5) to prevent analytes from adsorption on the capillary wall. However, in the case of rivastigmine, the detection sensitivity was too limited to determine the optical impurity of S-rivastigmine lower than 1% when buffer pH was 2.5. It was found that the detection sensitivity was improved 1.6 times just by raising the buffer pH value from 2.5 to 5.8. The poor column efficiency due to the adsorption of the analytes on the capillary wall was resolved by using dynamical coating of the capillary wall with the linear polyacrylamide solution. The experimental parameters such as the concentration of HS-β-CD, buffer pH and buffer ionic strength were optimized, respectively. The method was validated in terms of repeatability, linearity, limit of detection (LOD) and limit of quantitation (LOQ). Using the present method, the optical purity of nonracemic rivastigmine with the enantiomeric excess (ee) value of 99.14% was determined.

  6. Enantioseparation of citalopram analogues with sulfated β-cyclodextrin by capillary electrophoresis. (United States)

    Wang, Yadi; Zhang, Shusheng; Breitbach, Zachary S; Petersen, Hans; Ellegaard, Peter; Armstrong, Daniel W


    Capillary electrophoresis methods were developed for the enantiomeric separation of 27 citalopram analogues. Sulfated β-cyclodextrin was the most broadly selective and useful chiral selector. The separations of most of the citalopram analogue compounds reported in this work have not been reported previously. Excellent enantiomeric separations were obtained for 26 out of 27 compounds, and most of the separations were achieved within 10 min. The effects of chemical parameters such as chiral selector types, buffer types, chiral selector and buffer concentrations, buffer pH and organic modifiers on the separation were investigated. The influence of analyte structure on separation also was examined and discussed.

  7. Optimized Separation of Pharmacologically Active Xanthones from Secuidaca inappendiculata by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    TaoBO; XueDongYANG; 等


    A capillary electrophoresis (CE) method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically optimized with respect to pH, concentration of running buffers,addition of sulfated β-CD,applied voltage and column temperature.Baseline separation was achieved for the nine xanthones in less than 15 minutes using a background electrolyte consisting of 200 mmol/L borate (pH9.5) and 10 mmol/L sulfated β-CD.

  8. A new injection method for soil nutrient analysis in capillary electrophoresis (United States)

    Smolka, M.; Puchberger-Enengl, D.; Bipoun, M.; Fercher, G.; Klasa, A.; Krutzler, C.; Keplinger, F.; Vellekoop, M. J.


    We present a new method for the direct injection of liquid sample into a capillary electrophoresis (CE) device. Instead of a double-T injection mechanism, a single inlet provided with a membrane filter is used. From a reservoir on top of this inlet, the liquid directly enters the separation channel through the membrane. The driving force is a short electrical pulse. This avoids an additional sample channel, so that the chip needs only three microfluidic connects and no mechanical sample pumping is demanded. The high injection reproducibility and the comparatively simple setup open up the way for mobile application of soil analysis.

  9. Determination of diastereoisomeric alkaloids in urine by capillary electrophoresis with electrochemiluminescence detection

    Institute of Scientific and Technical Information of China (English)

    Yan Ming Liu; Long Fei Peng; Lin Mei; Li Juan Liu


    A new and simple capillary electrophoresis with electrochemiluminescence detection was developed for the separation and the quantification of a pair of diastereoisomeric alkaloids (ephedrine and pseudoephedrine). The limits of detection (S/N = 3) were 4.5 × 10-8 mol/L for ephedrine and 5.2×10-8 mol/L for pseudoephedrine, respectively. The RSDs of migration time and peak area were less than 1.3 and 2.5% (n = 5), respectively. The applicability of the propose method was illustrated in the determination of ephedrine and pseudoephedrine in human urine, ephedrine in nasal drops, and the monitoring of pharmacokinetics for pseudoephedrine.

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

    Institute of Scientific and Technical Information of China (English)


    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 β -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.

  11. Separation of multiply charged anions by capillary electrophoresis using alkyl phosphonium pairing agents. (United States)

    Feng, Qing; Wanigasekara, Eranda; Breitbach, Zachary S; Armstrong, Daniel W


    Two newly developed UV transparent phosphonium-based cationic reagents were evaluated as background electrolyte additives for capillary electrophoresis for the separation of multiply charged anions, including several complex anions. These cationic reagents showed moderate suppression of the electroosmotic flow, interacted with the analytes to improve their separation and often improved the peak shape. The effects of the additives and their concentration on the separation were studied, as well as the buffer type, pH, and voltage. The dicationic reagent effectively separated eight divalent anions within 17 min and the tetracationic reagent best separated nine trivalent anions, as well as a mixture of all the anions.

  12. Study on Rhizoma Chuanxiong based on capillary electrophoresis with amperometric detection

    Institute of Scientific and Technical Information of China (English)


    A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum con...

  13. Capillary electrophoresis with inhibited electrochemiluminescent detection for the trace analysis of epinephrine and dopamine

    Institute of Scientific and Technical Information of China (English)


    In this paper,a novel electrochemiluminescent (ECL) detection approach was developed for highly sensitive detection of ECL inhibitors based on the ECL inhibition of Ru(bpy)32+/2-(Dibutylamino)ethanol (DBAE) system. A microfluidic ECL detection cell was fabricated to couple with the capillary electrophoresis system,the electrochemical system and the postcolumn injection system. Both Ru(bpy)32+ and DBAE solutions were injected directly to the working electrode surface by a micro-infusion system to obtain a hi...

  14. Separation and determination of four active anthraquinones in Chinese herbal preparations by flow injection-capillary electrophoresis. (United States)

    Liu, Lihong; Fan, Liuyin; Chen, Hongli; Chen, Xingguo; Hu, Zhide


    A simple, rapid, and accurate method for the separation and determination of physcion, chrysophanol, aloe-emodin, and emodin in Rhubarb, Juemingzi, and Chinese herbal preparations was developed by combination of flow injection-capillary zone electrophoresis for the first time. The analysis was carried out using an unmodified fused-silica capillary (75 mm x 50 microm ID x 375 microm OD, effective separation length of 48 mm) and direct ultraviolet detection at 254 nm. By a series of optimization, the sample solvent consisted of NaOH (100 mmol/L) and ACN (1:1 v/v), and a running buffer composed of 15 mmol/L sodium borate - 12.5 mmol/L sodium dihydrogen phosphate - 42% v/v ACN (pH 10.1) was applied for the separation of the four anthraquinones. The separation was rapid and highly reproducible, with complete resolution of all four compounds within 6 min. The sample throughput rate could reach up to 12 per h. The repeatability (defined as relative standard deviation) was 4.45, 4.44, 4.34, 0.61% with peak height evaluation and 1.62, 0.89, 2.49, 2.19% with peak area evaluation for physcion, chrysophanol, aloe-emodin, and emodin, respectively.

  15. Capillary electrophoresis for the assay of fixed-dose combination tablets of artesunate and amodiaquine

    Directory of Open Access Journals (Sweden)

    Amin N’Cho


    Full Text Available Abstract Background Quality control of drugs in formulations is still a major challenge in developing countries. For the quality control of artesunate and amodiaquine tablets in fixed-dose combination, only liquid chromatographic methods have been proposed in the literature. There are no capillary electrophoretic methods reported for the determination of these active substances, although this technique presents several advantages over liquid chromatography (long lifetime, low price of the capillary, low volumes of electrolyte consumption in addition to simplicity. In this paper, a reliable capillary electrophoresis method has been developed and validated for the quality control of these drugs in commercial fixed-dose combination tablets. Methods Artesunate and amodiaquine hydrochloride in bilayer tablets were determined by micellar electrokinetic capillary chromatography (MEKC. Analytes were extracted from tablets by sonication with a solvent mixture phosphate buffer pH 7.0-acetonitrile containing benzoic acid as internal standard. Separation was carried out on Beckman capillary electrophoresis system equipped with fused silica capillary, 30 cm long (20 cm to detector × 50 μm internal diameter, using a 25 mM borate buffer pH 9.2 containing 30 mM sodium dodecyl sulfate as background electrolyte, a 500 V cm−1 electric field and a detection wavelength of 214 nm. Results Artesunate, amodiaquine and benzoic acid were separated in 6 min. The method was found to be reliable with respect to specificity,linearity of the calibration line (r2 > 0.995, recovery from synthetic tablets (in the range 98–102%, repeatability (RSD 2–3%, n = 7 analytical procedures. Application to four batches of commercial formulations with different dosages gave content in good agreement with the declared content. Conclusion The MEKC method proposed is reliable for the determination of artesunate and amodiaquine hydrochloride in fixed

  16. Aplicación de electroforesis capilar para la caracterización de gliadinas de trigos argentinos Use of capillary electrophoresis for characterization of Argentinean wheat gliadins

    Directory of Open Access Journals (Sweden)

    A. Colombo


    quality was assessed and wheat gliadins were extracted and analyzed by capillary electrophoresis. The results obtained corroborate the potential of free zone capillary electrophoresis for wheat gliadin separation. Additionally, only small amounts of sample are required and sample preparation is simple. Moreover, this technique involves straightforward protocols for capillary column cleaning and maintenance. These factors enable many of sample analyses in a relatively short time. Suitability of free zone capillary electrophoresis for cultivar discrimination based on gliadin profile was demonstrated, since both qualitative and quantitative differences among protein electrophoresis patterns were found. These distinctions allowed differentiation among several genotypes.

  17. Angiotensin-converting enzyme inhibition studies by natural leech inhibitors by capillary electrophoresis and competition assay. (United States)

    Deloffre, Laurence; Sautiere, Pierre-Eric; Huybrechts, Roger; Hens, Korneel; Vieau, Didier; Salzet, Michel


    A protocol to follow the processing of angiotensin I into angiotensin II by rabbit angiotensin-converting enzyme (ACE) and its inhibition by a novel natural antagonist, the leech osmoregulator factor (LORF) using capillary zonal electrophoresis is described. The experiment was carried out using the Beckman PACE system and steps were taken to determine (a) the migration profiles of angiotensin and its yielded peptides, (b) the minimal amount of angiotensin II detected, (c) the use of different electrolytes and (d) the concentration of inhibitor. We demonstrated that LORF (IPEPYVWD), a neuropeptide previously found in leech brain, is able to inhibit rabbit ACE with an IC(50) of 19.8 micro m. Interestingly, its cleavage product, IPEP exhibits an IC(50) of 11.5 micro m. A competition assay using p-benzoylglycylglycylglycine and insect ACE established that LORF and IPEP fragments are natural inhibitors for invertebrate ACE. Fifty-four percent of insect ACE activity is inhibited with 50 micro m IPEP and 35% inhibition with LORF (25 mm). Extending the peptide at both N- and C-terminus (GWEIPEPYVWDES) and the cleavage of IPEP in IP abolished the inhibitory activity of both peptides. Immunocytochemical data obtained with antisera raised against LORF and leech ACE showed a colocalization between the enzyme and its inhibitor in the same neurons. These results showed that capillary zonal electrophoresis is a useful technique for following enzymatic processes with small amounts of products and constitutes the first evidence of a natural ACE inhibitor in invertebrates.

  18. Heteroduplex analysis by capillary array electrophoresis for rapid mutation detection in large multiexon genes. (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Pérez-Cabornero, Lucía; Sanz, David J; Esteban-Cardeñosa, Eva; Miner, Cristina


    Heteroduplex analysis (HA) has proven to be a robust tool for mutation detection. HA by capillary array electrophoresis (HA-CAE) was developed to increase throughput and allow the scanning of large multiexon genes in multicapillary DNA sequencers. HA-CAE is a straightforward and high-throughput technique to detect both known and novel DNA variants with a high level of sensitivity and specificity. It consists of only three steps: multiplex-PCR using fluorescently labeled primers, heteroduplex formation and electrophoresis in a multicapillary DNA sequencer. It allows, e.g., the complete coding and flanking intronic sequences of BRCA1 and BRCA2 genes from two patients (approximately 25 kb each) to be scanned in a single run of a 16-capillary sequencer, and has enabled us to detect 150 different mutations to date (both single nucleotide substitutions, or SNSs, and small insertions/deletions). Here, we describe the protocol developed in our laboratory to scan BRCA1, BRCA2, MLH1, MSH2 and MSH6 genes using an ABI3130XL sequencer. This protocol could be adapted to other instruments or to the study of other large multiexon genes and can be completed in 7-8 h.

  19. Rapid identification and quantitation for oral bacteria based on short-end capillary electrophoresis. (United States)

    Chen, Jin; Ni, Yi; Liu, Chenchen; Yamaguchi, Yoshinori; Chen, Qinmiao; Sekine, Shinichi; Zhu, Xifang; Dou, Xiaoming


    High-speed capillary electrophoresis (HSCE) is a promising technology applied in ultra-rapid and high-performance analysis of biomolecules (such as nucleic acids, protein). In present study, the short-end capillary electrophoresis coupled with one novel space domain internal standard method (SDIS) was employed for the rapid and simultaneous analysis of specific genes from three oral bacteria (Porphyromonas gingivalis (P.g), Treponema denticola (T.d) and Tannerela forsythia (T.f)). The reliability, reproducibility and accuracy properties of above mentioned SDIS method were investigated in detail. The results showed the target gene fragments of P.g, T.d and T.f could be precisely, fast identified and quantitated within 95s via present short-end CE system. The analyte concentration and the ratio of space domain signals (between target sample and internal standard sample) featured a well linear relationship calculated via SDIS method. And the correlation coefficients R(2) and detection limits for P.g, T.d, T.f genes were 0.9855, 0.9896, 0.9969 and 0.077, 0.114 and 0.098ng/μl, respectively.

  20. Determination of ephedrine and pseudoephedrine by field-amplified sample injection capillary electrophoresis. (United States)

    Deng, Dongli; Deng, Hao; Zhang, Lichun; Su, Yingying


    A simple and rapid capillary electrophoresis method was developed for the separation and determination of ephedrine (E) and pseudoephedrine (PE) in a buffer solution containing 80 mM of NaH2PO4 (pH 3.0), 15 mM of β-cyclodextrin and 0.3% of hydroxypropyl methylcellulose. The field-amplified sample injection (FASI) technique was applied to the online concentration of the alkaloids. With FASI in the presence of a low conductivity solvent plug (water), an approximately 1,000-fold improvement in sensitivity was achieved without any loss of separation efficiency when compared to conventional sample injection. Under these optimized conditions, a baseline separation of the two analytes was achieved within 16 min and the detection limits for E and PE were 0.7 and 0.6 µg/L, respectively. Without expensive instruments or labeling of the compounds, the limits of detection for E and PE obtained by the proposed method are comparable with (or even lower than) those obtained by capillary electrophoresis laser-induced fluorescence, liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. The method was validated in terms of precision, linearity and accuracy, and successfully applied for the determination of the two alkaloids in Ephedra herbs.

  1. Determination of artificial sweeteners by capillary electrophoresis with contactless conductivity detection optimized by hydrodynamic pumping. (United States)

    Stojkovic, Marko; Mai, Thanh Duc; Hauser, Peter C


    The common sweeteners aspartame, cyclamate, saccharin and acesulfame K were determined by capillary electrophoresis with contactless conductivity detection. In order to obtain the best compromise between separation efficiency and analysis time hydrodynamic pumping was imposed during the electrophoresis run employing a sequential injection manifold based on a syringe pump. Band broadening was avoided by using capillaries of a narrow 10 μm internal diameter. The analyses were carried out in an aqueous running buffer consisting of 150 mM 2-(cyclohexylamino)ethanesulfonic acid and 400 mM tris(hydroxymethyl)aminomethane at pH 9.1 in order to render all analytes in the fully deprotonated anionic form. The use of surface modification to eliminate or reverse the electroosmotic flow was not necessary due to the superimposed bulk flow. The use of hydrodynamic pumping allowed easy optimization, either for fast separations (80s) or low detection limits (6.5 μmol L(-1), 5.0 μmol L(-1), 4.0 μmol L(-1) and 3.8 μmol L(-1) for aspartame, cyclamate, saccharin and acesulfame K respectively, at a separation time of 190 s). The conditions for fast separations not only led to higher limits of detection but also to a narrower dynamic range. However, the settings can be changed readily between separations if needed. The four compounds were determined successfully in food samples.

  2. Non-aqueous capillary electrophoresis of drugs: properties and application of selected solvents. (United States)

    Tjørnelund, J; Hansen, S H


    The electrophoretic mobility of selected acidic and basic test solutes have been determined in non-aqueous media prepared by adding various combinations of ammonium acetate, sodium acetate, methane sulphonic acid and acetic acid to acetonitrile, propylene carbonate, methanol, formamide, N-methylformamide, N,N-dimethylformamide and dimethylsulphoxide, respectively. The apparent pH (pH*) of these non-aqueous media have been measured and it was found that pH* is an important factor for the separations in non-aqueous capillary electrophoresis. However, in some solvents the concentration of sodium acetate has a strong influence on the mobility despite very small changes in pH*. Due to the fact that a change in one parameter influences a number of other parameters it is very difficult to conduct systematic studies in non-aqueous media and to compare the migration of the species at fixed pH* values from one solvent to another. Thus pH* is only of value for comparison when used with a specific solvent or solvent mixture. The viscosity of the above-mentioned solvents were measured at various temperatures and means to adjust the viscosity of the non-aqueous media used for capillary electrophoresis are discussed and the separation of ibuprofen and its major metabolites in urine is used as an example.

  3. 毛细管区带电泳-间接紫外检测法快速测定食品中乳糖、蔗糖、葡萄糖和果糖%Rapid determination of lactose,sucrose,glucose and fructose in foods by capillary zone electrophoresis with indirect ultraviolet detection

    Institute of Scientific and Technical Information of China (English)

    张欢欢; 李疆; 赵珊; 丁晓静; 王志


    A new and rapid method for the simultaneous determination of lactose,sucrose, glucose and fructose by capillary zone electrophoresis( CZE)with indirect ultraviolet detection was developed. The separation was completed with an uncoated fused-silica capillary with 30.2 cm of total length( effective length of 20 cm)× 50 μm. The separation buffer consisted of 4 mmol/L potassium sorbate,10 mmol/L sodium phosphate,30 mmol/L NaOH( pH 12. 56)and 0. 5 mmol/L hexadecytrimethylammonium bromide( CTAB). The separation was performed at a voltage of -8 kV with the ultraviolet detection at 254 nm. The analysis of the four carbohydrates was completed within 10 min. The limits of detection( S/N=3)for lactose,sucrose,glucose and fructose were 50,75,25 and 25 mg/L,and the limits of quantification( S/N=10)were 150,225,75 and 75 mg/L,respectively. The average recoveries for the four carbohydrates were in the range of 87. 0%-107. 0% with the relative standard deviations of 1. 2%-4. 7%. No organic solvent was consumed throughout the whole process of the analysis. The method was used for the analysis of nine food samples and a quality control sample. The results demonstrated that the method is simple,rapid,accurate,and suitable for the routine analysis of the four carbohy-drates in food samples.%建立了毛细管区带电泳-间接紫外检测快速测定食品中乳糖、蔗糖、葡萄糖和果糖的方法。以水或5 mmol/L醋酸为样品提取液,未涂层熔融石英毛细管(30.2 cm(有效长度20 cm)×50μm)为分离柱,4 mmol/L 山梨酸钾+10 mmol/L磷酸钠+30 mmol/L NaOH(pH 12.56)+0.5 mmol/L 十六烷基三甲基溴化铵(CTAB)为分离缓冲液,在-8 kV下分离,于254 nm波长下检测,10 min内实现了食品中上述4种糖的同时分离与测定。乳糖、蔗糖、葡萄糖和果糖的检出限( S/N=3)分别为50、75、25和25 mg/L,定量限( S/N=10)分别为150、225、75和75 mg/L,回收率在87.0%~107.0

  4. Determination of ephedrine and pseudoephedrine in Herba Ephedrae and Maxing Shigan Tang by capillary zone electrophoresis%毛细管区带电泳法测定麻黄及麻杏石甘汤中麻黄碱和伪麻黄碱的含量

    Institute of Scientific and Technical Information of China (English)

    景浩然; 郭怀忠; 王子君; 王敏; 张斌


    目的:采用毛细管区带电泳法测定麻黄及麻杏石甘汤中麻黄碱和伪麻黄碱.方法:电泳缓冲液为50 mmol·L~(-1)硼砂/20 mmol·L~(-1)苏氨酸缓冲溶液(1 mol·L~(-1) NaOH溶液调pH至9.27);紫外检测波长210 nm,分离电压15 kV;以苯巴比妥为内标物,采用压力进样(10 cm×20 s),柱温室温.结果:麻黄碱与伪麻黄碱的线性范围分别为21.3~213,8.4~84 mg·L~(-1),相关系数分别为0.999 6,0.999 5,检测限分别为1.45,1.48 mg·L~(-1),定量限分别为4.81,4.93 mg·L~(-1).将该法用于麻黄中麻黄碱与伪麻黄碱的含量测定,平均回收率分别为97.5,98.6%.结论:本法操作简便、快速、经济、灵敏度高,麻黄及麻杏石甘汤中麻黄碱及伪麻黄碱可获得满意的分离,可作为麻黄和麻杏石甘汤中麻黄碱和伪麻黄碱的含量测定方法.%Objective: To establish a method for the determination of ephedrine and pseudoephedrine in Herba Ephedrae and Maxing Shigan Tang by capillary zone electrophoresis. Method: The conditions of the experiment were optimized with a fused-silica capillary of 60 cm ×50 μm (50 cm effective length) in a running buffer of 50 mmol·L~(-1) borax-20 mmol·L~(-1) threonine (pH 9.27) and an applied voltage of 15 kV (room temperature). Samples were introduced by hydrodynamic injections (10 cm ×20 s)and determined with on-column UV monitoring at 210 nm. Phenobarbital was chosen as the internal standard. Result: Ephedrine and pseudoephedrine are separated successfully within 8 min. The linear responses covered the ranges from 21.3 to 213 mg·L~(-1) (r = 0.999 6) for ephedrine and from 8. 4 to 84 mg·L~(-1) ( r = 0. 999 5 ) for pseudoephedrine. The detection limits ( S/N = 3 ) of ephedrine and pseudoephedrine were shown to be 1.45 and 1.48 μg·mL~(-1) , respectively, The quantitation limits (S/N = 10) of ephedrine and pseudoephedrine were shown to be 4.81 and 4.93 mg·L~(-1) , respectively. The average recoveries for ephedrine and

  5. Surface initiated polymerization of a cationic monomer on inner surfaces of silica capillaries: analyte separation by capillary electrophoresis versus polyelectrolyte behavior. (United States)

    Witos, Joanna; Karesoja, Mikko; Karjalainen, Erno; Tenhu, Heikki; Riekkola, Marja-Liisa


    [2-(Methacryloyl)oxyethyl]trimethylammonium chloride was successfully polymerized by surface-initiated atom transfer radical polymerization method on the inner surface of fused-silica capillaries resulting in a covalently bound poly([2-(methacryloyl)oxyethyl]trimethylammonium chloride) coating. The coated capillaries provided in capillary electrophoresis an excellent run-to-run repeatability, capillary-to-capillary and day-to-day reproducibility. The capillaries worked reliably over 1 month with EOF repeatability below 0.5%. The positively charged coated capillaries were successfully applied to the capillary electrophoretic separation of three standard proteins and five β-blockers with the separation efficiencies ranging from 132,000 to 303,000 plates/m, and from 82,000 to 189,000 plates/m, respectively. In addition, challenging high- and low-density lipoprotein particles could be separated. The hydrodynamic sizes of free polymer chains in buffers used in the capillary electrophoretic experiments were measured for the characterization of the coatings.

  6. Combining ligation reaction and capillary gel electrophoresis to obtain reliable long DNA probes. (United States)

    García-Cañas, Virginia; Mondello, Monica; Cifuentes, Alejandro


    New DNA amplification methods are continuously developed for sensitive detection and quantification of specific DNA target sequences for, e.g. clinical, environmental or food applications. These new applications often require the use of long DNA oligonucleotides as probes for target sequences hybridization. Depending on the molecular technique, the length of DNA probes ranges from 40 to 450 nucleotides, solid-phase chemical synthesis being the strategy generally used for their production. However, the fidelity of chemical synthesis of DNA decreases for larger DNA probes. Defects in the oligonucleotide sequence result in the loss of hybridization efficiency, affecting the sensitivity and selectivity of the amplification method. In this work, an enzymatic procedure has been developed as an alternative to solid-phase chemical synthesis for the production of long oligonucleotides. The enzymatic procedure for probe production was based on ligation of short DNA sequences. Long DNA probes were obtained from smaller oligonucleotides together with a short sequence that acts as bridge stabilizing the molecular complex for DNA ligation. The ligation reactions were monitored by capillary gel electrophoresis with laser-induced fluorescence detection (CGE-LIF) using a bare fused-silica capillary. The capillary gel electrophoresis-LIF method demonstrated to be very useful and informative for the characterization of the ligation reaction, providing important information about the nature of some impurities, as well as for the fine optimization of the ligation conditions (i.e. ligation cycles, oligonucleotide and enzyme concentration). As a result, the yield and quality of the ligation product were highly improved. The in-lab prepared DNA probes were used in a novel multiplex ligation-dependent genome amplification (MLGA) method for the detection of genetically modified maize in samples. The great possibilities of the whole approach were demonstrated by the specific and sensitive

  7. Determination of biogenic amines in beer and wine by capillary electrophoresis-tandem mass spectrometry. (United States)

    Daniel, Daniela; Dos Santos, Vagner Bezerra; Vidal, Denis Tadeu Rajh; do Lago, Claudimir Lucio


    A capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) method for the simultaneous assessment of nine biogenic amines (spermine, spermidine, putrescine, cadaverine, histamine, phenylethylamine, tryptamine, tyramine, and urocanic acid) in commercial samples of beer and wine is introduced. The samples were submitted to a simple clean-up step with poly(vinylpolypyrrolidone) followed by filtration. Electrophoretic separation in a polyvinyl alcohol (PVA)-coated capillary using 0.5 mol L(-1) acetic acid (pH 2.5) as background electrolyte and detection by electrospray-tandem mass spectrometry was employed. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.996-0.999, and the limits of detection and limits of quantification were in the range of 1-2 μg L(-1) and 3-8 μg L(-1), respectively. The recovery values for samples spiked at three concentration levels (0.2, 0.5, and 1.0 mg L(-1)) ranged from 87 to 113% with standard deviation not greater than 5.8%. The use of a PVA-coated silica capillary allows suppressing the electroosmotic flow and, consequently, increasing of the separation efficiency. The method was successfully used to determine biogenic amines in commercial samples of beer and wine.

  8. Determination of impurities in heparin by capillary electrophoresis using high molarity phosphate buffers. (United States)

    Wielgos, Todd; Havel, Karalyn; Ivanova, Nadia; Weinberger, Robert


    Oversulfated chondroitin sulfate (OSCS), an impurity found in some porcine intestinal heparin samples was separated from intact heparin by capillary electrophoresis (CE) using a 600mM phosphate buffer, pH 3.5 as the background electrolyte in a 56cm x 25microm i.d. capillary. This method was confirmed in two separate labs, was shown to be linear, reproducible, robust, easy to use and provided the highest resolution and superior limits of detection compared to other available CE methods. Glycosoaminoglycans such as dermatan sulfate and heparan sulfate were separated and quantified as well during a single run. The heparin peak area response correlated well to values obtained using the official assay for biological activity. A high speed, high resolution version of the method was developed using 600mM lithium phosphate, pH 2.8 in a 21.5cm x 25microm i.d. capillary which provided limits of detection for OSCS that were below 0.1%.

  9. Quality criterion to optimize separations in capillary electrophoresis: Application to the analysis of harmala alkaloids. (United States)

    Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G


    In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model.

  10. High-Throughput Genetic Analysis and Combinatorial Chiral Separations Based on Capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Wenwan Zhong


    Capillary electrophoresis (CE) offers many advantages over conventional analytical methods, such as speed, simplicity, high resolution, low cost, and small sample consumption, especially for the separation of enantiomers. However, chiral method developments still can be time consuming and tedious. They designed a comprehensive enantioseparation protocol employing neutral and sulfated cyclodextrins as chiral selectors for common basic, neutral, and acidic compounds with a 96-capillary array system. By using only four judiciously chosen separation buffers, successful enantioseparations were achieved for 49 out of 54 test compounds spanning a large variety of pKs and structures. Therefore, unknown compounds can be screened in this manner to identify optimal enantioselective conditions in just one rn. In addition to superior separation efficiency for small molecules, CE is also the most powerful technique for DNA separations. Using the same multiplexed capillary system with UV absorption detection, the sequence of a short DNA template can be acquired without any dye-labels. Two internal standards were utilized to adjust the migration time variations among capillaries, so that the four electropherograms for the A, T, C, G Sanger reactions can be aligned and base calling can be completed with a high level of confidence. the CE separation of DNA can be applied to study differential gene expression as well. Combined with pattern recognition techniques, small variations among electropherograms obtained by the separation of cDNA fragments produced from the total RNA samples of different human tissues can be revealed. These variations reflect the differences in total RNA expression among tissues. Thus, this Ce-based approach can serve as an alternative to the DNA array techniques in gene expression analysis.

  11. Capillary electrophoresis of heparin and other glycosaminoglycans using a polyamine running electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Loegel, Thomas N.; Trombley, John D.; Taylor, Richard T. [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States); Danielson, Neil D., E-mail: [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States)


    Highlights: Black-Right-Pointing-Pointer Ethylenediamine is likely acting as an ion-pairing agent. Black-Right-Pointing-Pointer Oversulfated chondroitin sulfate is last peak instead of first peak. Black-Right-Pointing-Pointer There is about a factor of five improved detectability with a 12.5 min analysis time. Black-Right-Pointing-Pointer Use of a 50 {mu}m ID capillary is possible. - Abstract: This study involves the use of polyamines as potential resolving agents for the capillary electrophoresis (CE) of glycosaminoglycans (GAGs), specifically heparin, dermatan sulfate, chondroitin sulfate, over-sulfated chondroitin sulfate (OSCS), and hyaluronan. All of the compounds can be separated from each other with the exception of chondroitin sulfate and hyaluronan. Using optimization software, the final run conditions are found to be 200 mM ethylenediamine and 45.5 mM phosphate as the electrolyte with -14 V applied across a 50 {mu}m ID Multiplication-Sign 24.5 cm fused silica capillary at 15 Degree-Sign C. The ion migration order, with OSCS as the last instead of the first peak, is in contrast to previous reports using either a high molarity TRIS or lithium phosphate run buffer with narrower bore capillaries. Total analysis time is 12. 5 min and the relative standard deviation of the heparin migration time is about 2.5% (n = 5). The interaction mechanism between selected polyamines and heparin is explored using conductivity measurements in addition to CE experiments to show that an ion-pairing mechanism is likely.

  12. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2012-2014). (United States)

    Breadmore, Michael C; Tubaon, Ria Marni; Shallan, Aliaa I; Phung, Sui Ching; Abdul Keyon, Aemi S; Gstoettenmayr, Daniel; Prapatpong, Pornpan; Alhusban, Ala A; Ranjbar, Leila; See, Hong Heng; Dawod, Mohamed; Quirino, Joselito P


    One of the most cited limitations of capillary (and microchip) electrophoresis is the poor sensitivity. This review continues to update this series of biannual reviews, first published in Electrophoresis in 2007, on developments in the field of on-line/in-line concentration methods, covering the period July 2012-July 2014. It includes developments in the field of stacking, covering all methods from field-amplified sample stacking and large-volume sample stacking, through to ITP, dynamic pH junction, and sweeping. Attention is also given to on-line or in-line extraction methods that have been used for electrophoresis.

  13. Simultaneous determination of creatinine and acetate by capillary electrophoresis with contactless conductivity detector as a feasible approach for urinary tract infection diagnosis. (United States)

    Grochocki, Wojciech; Markuszewski, Michał J; Quirino, Joselito P


    Urinary tract infection (UTI) is one of the most common bacterial infection in human but its diagnosis is difficult. Metabolomic studies with nuclear magnetic resonance of urine have shown that acetic acid/creatinine ratio may be used for early UTI diagnosis. Here, a method for simultaneous determination of acetate and creatinine by capillary zone electrophoresis with contactless conductivity detector was developed for the first time. The separation was with 40mM MES and 20mM l-histidine as a background solution. The total time of a single run, including capillary conditioning, was less than 12min. The method was successfully demonstrated for analysis of actual and fortified human urine samples after methanol dilution. Analytical figures of merit such as linearity, LOQ, and repeatability (intraday and interday) were studied.

  14. Ultrasound-assisted emulsification microextraction for the determination of ephedrines in human urine by capillary electrophoresis with direct injection. Comparison with dispersive liquid-liquid microextraction. (United States)

    Alshana, Usama; Göğer, Nilgün G; Ertaş, Nusret


    Ultrasound-assisted emulsification microextraction and dispersive liquid-liquid microextraction were compared for extraction of ephedrine, norephedrine, and pseudoephedrine from human urine samples prior to their determination by capillary electrophoresis. Formation of a microemulsion of the organic extract with an aqueous solution (at pH 3.2) containing 10% methanol facilitated the direct injection of the final extract into the capillary. Influential parameters affecting extraction efficiency were systematically studied and optimized. In order to enhance the sensitivity further, field-amplified sample injection was applied. Under optimum extraction and stacking conditions, enrichment factors of up to 140 and 1750 as compared to conventional capillary zone electrophoresis were obtained resulting in limits of detection of 12-33 μg/L and 1.0-2.8 μg/L with dispersive liquid-liquid microextraction and ultrasound-assisted emulsification microextraction when combined with field-amplified sample injection. Calibration graphs showed good linearity for urine samples by both methods with coefficients of determination higher than 0.9973 and percent relative standard deviations of the analyses in the range of 3.4-8.2% for (n = 5). The results showed that the use of ultrasound to assist microextraction provided higher extraction efficiencies than disperser solvents, regarding the hydrophilic nature of the investigated analytes.

  15. Determination of Magnolol and Honokiol by Non-aqueous Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)


    Two active principles in traditional Chinese medicine Magnolia officinalis, magnolol and honokiol, were successfully separated by means of nonaqueous capillary electrophoresis. The effect of the composition of a nonaqueous buffer on column efficiency and resolution, and the effect of acid additives on peak shapes were researched. The separation was conducted with a running buffer in a mixture of methanol/acetonitrile/formamide (volume ratio: 1: 2: 2), in which the concentrations of Tris, acetic acid, and water were 60 mmol/L, 0. 04 mmol/L and 5% (volume fration),respectively, and the pH * (apperent pH) of the running buffer was 8. 96. Magnolol and honokiol were separated on baseline within 20 min. The relative standard deviation of the analytes' concentrations in the sample is 1.32% for magnolol and 1.60% for honokiol, and the recoveries of the spiked sample are 98.4% for magnolol and 98.0% for honokiol, respectively.

  16. Forensic ancestry analysis with two capillary electrophoresis ancestry informative marker (AIM) panels

    DEFF Research Database (Denmark)

    Santos, C; Fondevila, M; Ballard, D


    There is increasing interest in forensic ancestry tests, which are part of a growing number of DNA analyses that can enhance routine profiling by obtaining additional genetic information about unidentified DNA donors. Nearly all ancestry tests use single nucleotide polymorphisms (SNPs), but these......There is increasing interest in forensic ancestry tests, which are part of a growing number of DNA analyses that can enhance routine profiling by obtaining additional genetic information about unidentified DNA donors. Nearly all ancestry tests use single nucleotide polymorphisms (SNPs......), but these currently rely on SNaPshot single base extension chemistry that can fail to detect mixed DNA. Insertion-deletion polymorphism (Indel) tests have been developed using dye-labeled primers that allow direct capillary electrophoresis detection of PCR products (PCR-to-CE). PCR-to-CE maintains the direct...

  17. A multiscale products technique for denoising of DNA capillary electrophoresis signals (United States)

    Gao, Qingwei; Lu, Yixiang; Sun, Dong; Zhang, Dexiang


    Since noise degrades the accuracy and precision of DNA capillary electrophoresis (CE) analysis, signal denoising is thus important to facilitate the postprocessing of CE data. In this paper, a new denoising algorithm based on dyadic wavelet transform using multiscale products is applied for the removal of the noise in the DNA CE signal. The adjacent scale wavelet coefficients are first multiplied to amplify the significant features of the CE signal while diluting noise. Then, noise is suppressed by applying a multiscale threshold to the multiscale products instead of directly to the wavelet coefficients. Finally, the noise-free CE signal is recovered from the thresholded coefficients by using inverse dyadic wavelet transform. We compare the performance of the proposed algorithm with other denoising methods applied to the synthetic CE and real CE signals. Experimental results show that the new scheme achieves better removal of noise while preserving the shape of peaks corresponding to the analytes in the sample.

  18. Hydrogel plug for independent sample and buffer handling in continuous microchip capillary electrophoresis (United States)

    Puchberger-Enengl, Dietmar; Bipoun, Mireille; Smolka, Martin; Krutzler, Christian; Keplinger, Franz; Vellekoop, Michael J.


    In microchip capillary electrophoresis most frequently electrokinetic sample injection is utilized, which does not allow pressure driven sample handling and is sensitive for pressure drops due to different reservoir levels. For efficient field tests a multitude of samples have to be processed with the least amount of external equipment. We present the use of a hydrogel plug to separate the sample from clean buffer to enable independent sample change and buffer refreshment. In-situ polymerization of the gel does away with complex membrane fabrication techniques. The sample is electrokinetically injected through the gel and subsequently separated by a voltage between the second gel inlet and the buffer outlet. By blocking of disturbing flows by the gel barrier a well-defined ion plug is obtained. After each experiment, the sample and the separation channel can be flushed independently, allowing for a continuous operation mode in order to process multiple samples.

  19. Detection of Elevated Signaling Amino Acids in Human Diabetic Vitreous by Rapid Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Miao-Jen Lu


    Full Text Available Elevated glutamate is implicated in the pathology of PDR. The ability to rapidly assess the glutamate and amino acid content of vitreous provides a more complete picture of the chemical changes occurring at the diabetic retina and may lead to a better understanding of the pathology of PDR. Vitreous humor was collected following vitrectomies of patients with PDR and control conditions of macular hole or epiretinal membrane. A capillary electrophoresis method was developed to quantify glutamate and arginine. The analysis is relatively fast (<6 minutes and utilizes a poly(ethyleneoxide and sodium dodecylsulfate run buffer. Both amino acid levels show significant increases in PDR patients versus controls and are comparable to other reports. The levels of vitreal glutamate vary inversely with the degree of observed hemorrhage. The results demonstrate a rapid method for assessment of a number of amino acids to characterize the chemical changes at the diabetic retina to better understand tissue changes and potentially identify new treatments.

  20. Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Po-Ling Chang


    Full Text Available Nowadays, owing to the increasing population and the attempts to satisfy its needs, pesticides are widely applied to control the quantity and quality of agricultural products. However, the presence of pesticide residues and their metabolites in environmental samples is hazardous to the health of humans and all other living organisms. Thus, monitoring these compounds is extremely important to ensure that only permitted levels of pesticide are consumed. To this end, fast, reliable, and environmentally friendly methods that can accurately analyze dilute, complex samples containing both parent substances and their metabolites are required. Focusing primarily on research published since 2010, this review summarizes the use of various sample pretreatment techniques to extract pesticides from various matrices, combined with on-line preconcentration strategies for sensitivity improvement, and subsequent capillary electrophoresis analysis.

  1. Analysis of Glutamic Acid in Cerebrospinal Fluid by Capillary Electrophoresis with High Frequency Conductivity Detection

    Institute of Scientific and Technical Information of China (English)

    Hai Yun ZHAI; Jun Mei WANG; Xiao Li YAO; Xue Cai TAN; Pei Xiang CAI; Zuan Guang CHEN


    A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillary electrophoresis with high frequency conductivity detection (contactless conductivity detection) was described. The CSF sample was pretreated with silver cation resin to remove high concentration of Cl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8 mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of 5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used for analysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.

  2. Quantification of Fumaria officinalis isoquinoline alkaloids by nonaqueous capillary electrophoresis-electrospray ion trap mass spectrometry. (United States)

    Sturm, Sonja; Strasser, Eva-Maria; Stuppner, Hermann


    A capillary electrophoresis (CE) method using non-aqueous (NA) separation solutions combined with an ion trap mass spectrometer (MS and MS/MS) as detection device is presented for the separation, identification and quantification of isoquinoline alkaloids from Fumaria officinalis. The best results were obtained with a mixture of acetonitrile-methanol (9:1, v/v) containing 60mM ammonium acetate and 2.2M acetic acid as running electrolyte and an applied voltage of 30 kV. Electrospray MS measurements were performed in the positive ionization mode with isopropanol-water (1:1, v/v) as sheath liquid at a flow rate of 3 microl/min. Alkaloids were detected as [M+H](+)-ions and showed typical fragmentation patterns in MS/MS experiments. The developed assay was used for the quantification of seven isoquinoline alkaloids representing different structural subtypes in Fumariae herba extracts and F. herba containing phytopharmaceuticals.

  3. Electrostatic interaction mechanism on the separation of phenols by non-aqueous capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    WEI WeiLi; YIN YongGuang; XIA ZhiNing; CHEN ZhiTao; LIU WeiQi


    The electrostatic interaction between additive and analyte is of great importance to non-aqueous capillary electrophoresis (NACE) separation. Three tetraalkylammonium bromides and acetonitrile were applied as additives and running solvent respectively. The effect of alkyl chain length and concentration of additive on electrostatic interactions was investigated by the separation of phenols. The separation ability was found to increase with decreasing alkyl chain length of the additive, and the resolution values were increased with increasing additive concentration. The separation was seriously deteriorated after a little amount of water was added in the running solution. Furthermore, the electrostatic interaction is strong under the conditions of low electron cloud density, weak steric hindrance and multi-interaction sites. Thus, the separation result can be predicted by theoretical analysis, which is helpful for the separation of other substances in NACE based on electrostatic interaction.

  4. Development of a liquid-junction/low-flow interface for phosphate buffer capillary electrophoresis mass spectrometry. (United States)

    Li, Fu-An; Huang, Ju-Li; Shen, Shang-Yu; Wang, Che-Wei; Her, Guor-Rong


    To alleviate ion suppression from phosphate buffer and to preserve separation integrity, a new capillary electrophoresis mass spectrometry (CE-MS) interface was developed. The interface consisted of a low-flow interface and a liquid junction. In this design, both the inlet reservoir and the liquid-junction reservoir were filled with phosphate running buffer. Because the phosphate anions in the column migrated toward the inlet reservoir (away from the electrospray ionization (ESI) source) the problem of ion suppression in ESI was avoided. The liquid junction was incorporated to eliminate issues of degraded separation observed when sheath liquid interfaces use different buffers for separation and MS analysis attributed to differences in anion velocity. The utility of the interface was demonstrated by the analysis of antihistamines at pH 3.5 and the analysis of perfluorocarboxylic acid at pH 9.5.

  5. Capillary electrophoresis of miniSTR markers to genotype highly degraded DNA samples. (United States)

    Coble, Michael D


    The amplification of short tandem repeat (STR) markers throughout the human nuclear DNA genome are used to associate crime scene evidence to the perpetrator's profile in criminal investigations. For highly challenged or compromised materials such as stains exposed to the elements, skeletal remains from missing persons cases, or fragmented and degraded samples from mass disasters, obtaining a full STR profile may be difficult if not impossible. With the introduction of short amplicon STR or "miniSTR" typing, it is possible to obtain STR genetic information from highly challenged samples without the need to sequence the hypervariable regions of the mitochondrial DNA (mtDNA) genome. Non-Combined DNA Index System (CODIS) STR markers have been developed to obtain information beyond the core CODIS loci. This chapter will focus on the steps necessary to prepare and use one of the non-CODIS (NC) multiplexes, NC01 (Coble and Butler 2005), for analysis on capillary electrophoresis instrumentation.

  6. High throughput DNA sequence variant detection by conformation sensitive capillary electrophoresis and automated peak comparison. (United States)

    Davies, Helen; Dicks, Ed; Stephens, Philip; Cox, Charles; Teague, Jon; Greenman, Chris; Bignell, Graham; O'meara, Sarah; Edkins, Sarah; Parker, Adrian; Stevens, Claire; Menzies, Andrew; Blow, Matt; Bottomley, Bill; Dronsfield, Mark; Futreal, P Andrew; Stratton, Michael R; Wooster, Richard


    We report the development of a heteroduplex-based mutation detection method using multicapillary automated sequencers, known as conformation-sensitive capillary electrophoresis (CSCE). Our optimized CSCE protocol detected 93 of 95 known base substitution sequence variants. Since the optimization of the method, we have analyzed 215 Mb of DNA and identified 3397 unique variants. An analysis of this data set indicates that the sensitivity of CSCE is above 95% in the central 56% of the average PCR product. To fully exploit the mutation detection capacity of this method, we have developed software, canplot, which automatically compares normal and test results to prioritize samples that are most likely to contain variants. Using multiple fluorescent dyes, CSCE has the capacity to screen over 2.2 Mb on one ABI3730 each day. Therefore this technique is suitable for projects where a rapid and sensitive DNA mutation detection system is required.

  7. Application of 2,3-Naphthalenediamine in Labeling Natural Carbohydrates for Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Jim-Min Fang


    Full Text Available Neutral and acidic monosaccharide components in Ganoderma lucidum polysaccharide are readily labeled with 2,3-naphthalenediamine, and the resulting saccharide-naphthimidazole (NAIM derivatives are quantified by capillary electrophoresis (CE in borate buffer. Using sulfated-α-cyclodextrin as the chiral selector, enantiomers of monosaccharide-NAIMs are resolved on CE in phosphate buffer, allowing a simultaneous determination of the absolute configuration and sugar composition in the mucilage polysaccharide of a medicinal herb Dendrobium huoshanense. Together with the specific enzymatic reactions of various glycoside hydrolases on the NAIM derivatives of glycans, the structures of natural glycans can be deduced from the digestion products identified by CE analysis. Though heparin dissachrides could be successfully derived with the NAIM-labeling method, the heparin derivatives with the same degree of sulfation could not be separated by CE.

  8. Capillary electrophoresis with electrochemiluminescence detection for the analysis of quinolone drugs and pharmacokinetics study

    Institute of Scientific and Technical Information of China (English)

    Yan Ming Liu; Jun Tao Cao; Hui Wang


    A novel method for the determination of two quinolone drugs norfloxacin (NOR) and levofloxacin (LVX) was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship (r ≥ 0.9991) between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection (LOD, S/N = 3) in standard solution are 4.8 × 10-7 mol/L for NOR and 6.4 × 10-7 mol/L for LVX, respectively. The limits of quantitation (LOQ, S/N = 10) in real human urine samples are 1.2 × 10-6 mol/L for NOR and 1.4 × 10-6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the study of pharmacokinetics of NOR.

  9. Pulsed-field capillary electrophoresis: optimizing separation parameters with model mixtures of sulfonated polystyrenes. (United States)

    Sudor, J; Novotny, M V


    The electrophoretic transport of high molecular weight charged solutes, both flexible and stiff polymers, has been studied by capillary electrophoresis under constant-field and pulsed-field conditions. Sulfonated polystyrenes were used as model solutes in different entangled polymer solutions. First, changes of the end-to-end distance vectors of flexible polymers were examined through the mobility/potential-gradient curves. Under pulsed-field conditions, the influence of different pulse shapes, frequencies, and amplitudes of forward and backward pulses on the electrophoretic mobilities of model solutes was studied. Resolution of the mixture components was strongly affected by changes in frequency of both sine-wave and square-wave pulses. The experimental results obtained under pulse-field conditions are roughly in agreement with the existing theories of electrophoretic transport.

  10. The selective determination of sulfates, sulfonates, and phosphates in urine by capillary electrophoresis/mass spectrometry. (United States)

    Bunz, Svenja-Catharina; Neusüß, Christian


    Metabolite identification and metabolite profiling are of major importance in the pharmaceutical and clinical context. However, anions of biological relevance such as sulfates, sulfonates, and phosphates are rarely included in common techniques for metabolite studies. In this protocol, we demonstrate a unique method to selectively determine these anions. The method comprises a capillary electrophoresis separation using an acidic background electrolyte (pH ≤ 2) and anodic detection by mass spectrometry via negative electrospray ionization. In this way, only anions of strong acids like sulfates are determined. The selectivity for sulfur-containing species is proved based on the specific isotopic ratios. In conjunction with the accurate mass from the time-of-flight mass spectrometer, the presented method is well suited for clinical and pharmaceutical applications to identify possible metabolites and to quantify known metabolites.

  11. Ceramic capillary electrophoresis chip for the measurement of inorganic ions in water samples. (United States)

    Fercher, Georg; Haller, Anna; Smetana, Walter; Vellekoop, Michael J


    We present a microchip capillary electrophoresis (CE) device build-up in low temperature co-fired ceramics (LTCC) multilayer technology for the analysis of major inorganic ions in water samples in less than 80 s. Contactless conductivity measurement is employed as a robust alternative to direct-contact conductivity detection schemes. The measurement electrodes are placed in a planar way at the top side of the CE chip and are realized by screen printing. Laser-cutting of channel and double-T injector structures is used to minimize irregularities and wall defects, elevating plate numbers per meter up to values of 110,000. Lowest limit of detection is 6 microM. The cost efficient LTCC module is attractive particularly for portable instruments in environmental applications because of its chemical inertness, hermeticity and easy three-dimensional integration capabilities of fluidic, electrical and mechanical components.

  12. Determination of flunixin in equine urine and serum by capillary electrophoresis. (United States)

    Gu, X; Meleka-Boules, M; Chen, C L; Ceska, D M; Tiffany, D M


    A capillary electrophoresis (CE) and a solid-phase extraction method was developed for the determination of flunixin in equine urine and serum. The suitable CE run conditions were described. The factors affecting flunixin recovery rates were investigated and optimum solid-phase extraction conditions for flunixin in equine urine and serum were established. Limits of detection and quantitation were 3.4 and 5.6 ng/ml for serum and 16.9 and 33.1 ng/ml for urine, respectively. The recoveries exceeded 96% for urine and 79% for serum. Urine samples from race horses and urine and serum samples from a mare administrated with flunixin were analyzed with this procedure.

  13. Signal Detection of Multi-Channel Capillary Electrophoresis Chip Based on CCD (United States)

    Lv, Hongfeng; Yan, Weiping; Yang, Xiaobo; Li, Jiechao; Zhu, Jieying


    A kind of multi-channel capillary electrophoresis (CE) chip signal detection system based on CCD was developed. The output signal of the CCD sensor was processed by a series of pre-processing circuits and ADC, and then it was collected by the Field Programmable Gate Array (FPGA) chip which communicated with a host computer. The core in FPGA was designed to control the signal flow of the CCD and transfer the data to PC based on a Nios II embedded soft-processor. The application of PC was used to store the data and demonstrate the curve. The measurement of the fluorescent signals for different concentration Rhodamine B dyes is presented and the comparison with other detection systems is also discussed.

  14. Investigation of interaction between the drug and cell membrane by capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)


    By introducing cell membrane into electrophoretic buffer as pseudo-stationary phase,a novel capillary electrophoresis method was established to explore the interaction between drugs and cell membrane,where the interaction between citalopram and rabbit red blood cell membrane was used as an example. A series of concentrations of cell membrane were suspended into the running buffer by peak-shift method. The binding constant of citalopram to rabbit red blood cell membrane of 0.977 g-1·L was obtained after treatment of Scatchard plot. This method could provide not only a new way for the investigation on the interactions between drugs and cell membrane,but also a new approach for high throughput screening of the drug membrane permeability,biological activity,and evaluating drugs in vivo.

  15. Extraction of rutin from buckwheat (Fagopyrum esculentumMoench) seeds and determination by capillary electrophoresis. (United States)

    Kreft, S; Knapp, M; Kreft, I


    The content of the flavonoid rutin was determined in different milling fractions of buckwheat seeds and in buckwheat stems, leaves, and flowers. The extraction was performed by using a solvent containing 60% of ethanol and 5% of ammonia in water. The extracts were analyzed by capillary electrophoresis (running buffer of 50 mM borate (pH 9.3), 100 mM sodium dodecyl sulfate; determination at 380 nm). In bran fractions the concentration of rutin was 131-476 ppm, and in flour fractions 19-168 ppm. On average, about 300, 1000, and 46000 ppm of rutin were found in leaves, stems, and flowers, respectively. The results indicate that buckwheat could be an important nutritional source of flavonoids, especially in countries with a low mean daily flavonoid intake.

  16. Stability and Determination of Metamizole Sodium by Capillary Electrophoresis Analysis Combined with Infra-red Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    XIANG Qian; NIU Gang; WU Xian-hua; CHEN Gang


    Metamizole sodium was chosen as a representative of unstable analytes for investigation by discusing the effects of oxygen and solvent on its degradation reaction using the capillary electrophoresis technique. A possible degradation mechanism was deduced from the observed behavior and was confirmed by infra-red spectroscopic study. The degradation reaction could be inhibited obviously by methanol instead of water as the solvent of analyte. Under the optimized conditions: separation voltage of 20 kV, and 5 mmol/L disodium hydrogen phosphate and 5 mmol/L borax with 10% methanol(pH 9. 12) as the running buffer, the standard curve of metamizole sodium was linear in a range of 3.77-74.07 mg/L. A satisfactory result was achieved when the technique was used to detect metamizole sodium in tablet.

  17. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species

    Directory of Open Access Journals (Sweden)

    Alice Jernigan


    Full Text Available Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green and eukaryotic (green and brown algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis, five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata, and one brown algae (Ectocarpus sp. were examined and CE-SSCP electropherogram “fingerprints” were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred.

  18. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species. (United States)

    Jernigan, Alice; Hestekin, Christa


    Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP) was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green) and eukaryotic (green and brown) algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis), five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata), and one brown algae (Ectocarpus sp.) were examined and CE-SSCP electropherogram "fingerprints" were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred.

  19. Automatic Combination of Microfluidic Nanoliter-Scale Droplet Array with High-Speed Capillary Electrophoresis (United States)

    Li, Q.; Zhu, Y.; Zhang, N.-Q.; Fang, Q.


    In this paper, we developed a novel approach for interfacing a microfluidic two-dimensional droplet array to a high-speed capillary electrophoresis (HSCE) system. Picoliter-scale sample injection (ca. 200 pL) from a nanoliter-scale droplet array covered by nonvolatile oil was automatically achieved using the spontaneous injection mode, without the interference from the cover oil and the need of special droplet extraction interface as in previously reported systems. The system was applied in consecutive separations of 25 different samples of amino acids with a whole separation time less than 15 min, as well as on-line monitoring of in-droplet derivatizing reaction of amino acids by fluorescein isothiocyanate (FITC) over 3 hours. High separation speed (up to 100 samples per hour) and high separation efficiency (up to 9.22 × 105 N/m) were achieved.

  20. Applications of capillary electrophoresis with chemiluminescence detection in clinical, environmental and food analysis. A review

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Francisco J.; Airado-Rodríguez, Diego; Moreno-González, David; Huertas-Pérez, José F.; García-Campaña, Ana M., E-mail:


    This paper reviews the latest developments and analytical applications of chemiluminescence detection coupled to capillary electrophoresis (CE-CL). Different sections considering the most common CL systems have been included, such as the tris(2,2′-bipyridine)ruthenium(II) system, the luminol and acridinium derivative reactions, the peroxyoxalate CL or direct oxidations. Improvements in instrumental designs, new strategies for improving both resolution and sensitivity, and applications in different fields such as clinical, pharmaceutical, environmental and food analysis have been included. This review covers the literature from 2010 to 2015. - Highlights: • An up-to-date critical review about the evolution of CE-CL is presented. • Tris(2,2′-bipyridine)ruthenium(II) and luminol as the most used CL systems. • Instrumental designs and strategies for improving resolution and sensitivity. • Applications in clinical, pharmaceutical, environmental and food analysis.

  1. Correlation between Molecular Structures and Relative Electrophoretic Mobility in Capillary Electrophoresis: Alkylpyridines

    Institute of Scientific and Technical Information of China (English)

    YAO, Xiao-Jun; FAN, Bo-Tao; DOUCET, J. P.; PANAYE, A.; LIU, Man-Cang; ZHANG, Rui-Sheng; HU, Zhi-De


    The quantitative relationship between relative electrophoretic mobility in capillary electrophoresis for a series of 31 closely related alkylpyridines and their molecular structures was studied by using CODESSA. According to the t-test on the results, we found that the three most important descriptors affecting the mobility are the relative number of rings (NR), Min e-n attraction for a C-N bond (MEN) and average complementary information index (ACIC). With these structure descriptors a good three-parameter linear model was developed to correlate the mobility of these compounds with their structures. This model can not only correctly predict the migration behavior of these compounds, but also find the structural factors which are responsible for the migration behavior of these compounds,thus can help to explain the separation mechanism of these compounds. The method used in this work can also be extended to the mobility-structure relationship research of other compounds.

  2. Development of a capillary electrophoresis method for the simultaneous determination of cephalosporins

    Directory of Open Access Journals (Sweden)

    Hancu Gabriel


    Full Text Available A rapid and simple capillary electrophoresis method has been developed for the simultaneous determination of six extensively used cephalosporin antibiotics (cefaclor, cefadroxil, cefalexin, cefuroxim, ceftazidim, ceftriaxon. The determination of cephalosporins was performed at a pH 6.8, using a 25 mM phospate - 25 mM borate mixed buffer, + 25 kV voltage at a temperature of 25 °C. We achieved a baseline separation in approximately 10 minutes. The separation resolution was increased by addition of an anionic surfactant, 50 mM sodium dodecyl sulfate, to the buffer solution. The proposed separation was evaluated on the basis of detection and quantification limits, effective electrophoretic mobility and relative standard deviation for migration times and peak areas.

  3. Analysis of Soft Drinks: UV Spectrophotometry, Liquid Chromatography, and Capillary Electrophoresis (United States)

    McDevitt, Valerie L.; Rodriguez, Alejandra; Williams, Kathryn R.


    Instrumental analysis students analyze commercial soft drinks in three successive laboratory experiments. First, UV multicomponent analysis is used to determine caffeine and benzoic acid in Mello YelloTM using the spectrophotometer's software and manually by the simultaneous equations method. The following week, caffeine, benzoic acid and aspartame are determined in a variety of soft drinks by reversed-phase liquid chromatography using 45% methanol/55% aqueous phosphate, pH 3.0, as the mobile phase. In the third experiment, the same samples are analyzed by capillary electrophoresis using a pH 9.4 borate buffer. Students also determine the minimum detection limits for all three compounds by both LC and CE. The experiments demonstrate the analytical use and limitations of the three instruments. The reports and prelab quizzes also stress the importance of the chemistry of the three compounds, especially the relationships of acid/base behavior and polarity to the LC and CE separations.

  4. Capillary electrophoresis-electrochemistry microfluidic system for the determination of organic peroxides (United States)

    Wang, Joseph; Escarpa, Alberto; Pumera, Martin; Feldman, Jason; Svehla, D. (Principal Investigator)


    A microfluidic analytical system for the separation and detection of organic peroxides, based on a microchip capillary electrophoresis device with an integrated amperometric detector, was developed. The new microsystem relies on the reductive detection of both organic acid peroxides and hydroperoxides at -700 mV (vs. Ag wire/AgCl). Factors influencing the separation and detection processes were examined and optimized. The integrated microsystem offers rapid measurements (within 130 s) of these organic-peroxide compounds, down to micromolar levels. A highly stable response for repetitive injections (RSD 0.35-3.12%; n = 12) reflects the negligible electrode passivation. Such a "lab-on-a-chip" device should be attractive for on-site analysis of organic peroxides, as desired for environmental screening and industrial monitoring.

  5. Protein A Detection Based on Quantum Dots-Antibody Bioprobe Using Fluorescence Coupled Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Lin Qiu


    Full Text Available In this report, fluorescence detection coupled capillary electrophoresis (CE-FL was used to detect Protein A. Antibody was first labeled with Cy5 and then mixed with quantum dots (QDs to form QDs-antibody bioprobe. Further, we observed fluorescence resonance energy transfer (FRET from QDs donor to Cy5 acceptor. The bioprobe was formed and brought QDs and Cy5 close enough to allow FRET to occur. After adding protein A, the FRET system was broken and caused the FRET signal to decrease. Thus, a new method for the determination of protein A was proposed based on the FRET signal changes. This study provides a new trail of thought for the detection of protein.

  6. Determination of metoprolol in rabbit blood using capillary electrophoresis with laser-induced fluorescence detection

    Institute of Scientific and Technical Information of China (English)

    Yu Yun Chen; Wei Ping Yang; Zhu Jun Zhang


    This work described a sensitive method for determination of metoprolol in rabbit plasma. The method involved purification by ultrafiltration, derivatization with fluorescein isothiocyanate, determination by capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detector. Other components in plasma including a variety of amino acids and proteins did not interfere with the determination of metoprolol in experimental condition. The assay had a wide range (2.0-500 ng/mL) of linearity and a detection limit of 0.8 ng/mL. The intra-and inter-day precisions were satisfactory with relative standard deviation (RSD) less than 10.0% and accuracy within 10.0%. This method was successfully applied to pharmacokinetic study of metoprolol in rabbit blood. (c) 2010 Yu Yun Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  7. Using Capillary Electrophoresis to Determine the Purity of Acetylsalicylic Acid Synthesized in the Undergraduate Laboratory (United States)

    Welder, Frank; Colyer, Christa L.


    Capillary electrophoresis (CE), although a powerful analytical tool, has found only limited application in undergraduate laboratory study. In an effort to expose freshman and sophomore chemistry students to this technique, thereby giving them practical instrumental experience early in their careers, we propose to use CE in the analysis of student-synthesized acetylsalicylic acid (ASA). The synthesis of ASA from salicylic acid (SA) is a routine undergraduate laboratory, although students rarely have the opportunity to test the purity of their product. The CE method described herein provides students with a method to test purity and yield of their product and to determine the effect of aging on their sample. CE can accomplish this in a short period of time, with minimal disruption to the regular laboratory curriculum. Optimized separation conditions, limits of detection, and linear range for ASA and SA are also given.

  8. Single strand conformation polymorphism analysis of candidate genes for reliable identification of alleles by capillary array electrophoresis. (United States)

    We investigated the reliability of capillary array electrophoresis-SSCP to determine if it can be used to identify novel alleles of candidate genes in a germplasm collection. Both strands of three different size fragments (160 bp, 245 pb and 437 bp) that differed by one or more nucleotides in sequen...

  9. Separation and identification of neuropeptide Y, two of its fragments and their degradation products using capillary electrophoresis mass spectrometry

    NARCIS (Netherlands)

    Ensing, K; de Boer, Theo; Schreuder, N; de Zeeuw, RA


    This paper describes the development of an analytical method for the separation and identification of neuropeptide Y (NPY) and two important NPY fragments by capillary electrophoresis (CE) arid mass spectrometry (MS). A satisfactory separation and the highest sensitivity were obtained with formic ac

  10. Fluorescence- and capillary electrophoresis (CE)-based SSR DNA fingerprinting and a molecular identity database for the Louisiana sugarcane industry (United States)

    A database of Louisiana sugarcane molecular identity has been constructed and is being updated annually using FAM or HEX or NED fluorescence- and capillary electrophoresis (CE)-based microsatellite (SSR) fingerprinting information. The fingerprints are PCR-amplified from leaf DNA samples of current ...

  11. Determination of Roxithromycin Tablets by Capillary Electrophoresis Employing Non-aqueous Media with Square-wave Amperometric Detection

    Institute of Scientific and Technical Information of China (English)


    A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.

  12. Electrochemical Detection of Alkaline Phosphatase in BALB/c Mouse Fetal Liver Stromal Cells with Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Xue Mei SUN; Dong LI; Zeng Liang BAI; Wen Rui JIN


    A method for determination of alkaline phosphatase (ALP) in BALB/c mouse fetal liver stromal cells has been described based on the catalytic reaction. After the cell extract is incubated with the substrate disodium phenyl phosphate, the reaction product phenol generated by ALP is determined by capillary electrophoresis with electrochemical detection.

  13. Structural and conformational variants of human beta2-microglobulin characterized by capillary electrophoresis and complementary separation methods

    DEFF Research Database (Denmark)

    Heegaard, Niels H H; Rovatti, Luca; Nissen, Mogens H;


    The small (Mr = 11729) serum protein beta2-microglobulin is prone to precipitate as amyloid in a protein conformational disorder (PCD) that occurs in a significant number of patients on chronic hemodialysis. Analyses by capillary electrophoresis (CE) were undertaken to study beta2-microglobulin...

  14. DNA Sequencing by Capillary Electrophoresis Using Quasi-inter penetrating Network Formed by Polyacrylamide and Poly(N-hydroxymethylacrylamide)

    Institute of Scientific and Technical Information of China (English)

    Wen Long ZHANG; Yan Mei WANG


    Quasi-interpenetrating network formed by polyacrylamide and poly (N-hydroxymethylacrylamide) was designed, synthesized, and tested for DNA sequencing by capillary electrophoresis. The performance of quasi-IPN on DNA sequencing was determined by the acrylamide to N-hydroxymethylacrylamide molar ratio and sequencing temperature.

  15. A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian-Bo, E-mail:; Cui, Ting; Zhang, Wen-Wen; Deng, Ning


    Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products.

  16. Determination of the enantiomeric purity of (-) terbutaline by capillary electrophoresis using cyclodextrins as chiral selectors in a polyethylene glycol gel

    NARCIS (Netherlands)

    de Boer, Theo; Ensing, K


    A method was developed for determination of the enantiomeric purity of the therapeutic-pharmacological active (-)-enantiomer of terbutaline using cyclodextrins as a chiral selector dissolved in a removable liquid polyethylene glycol gel by use of capillary electrophoresis. The effect of temperature,

  17. Powder-blasting technology as an alternative tool for microfabrication of capillary electrophoresis chips with integrated conductivity sensors

    NARCIS (Netherlands)

    Schlautmann, Stefan; Wensink, Henk; Schasfoort, Richard; Elwenspoek, Miko; Berg, van den Albert


    The fabrication and characterization of a microfluidic device for capillary electrophoresis applications is presented. The device consists of a glass chip which contains a single separation channel as well as an integrated conductivity detection cell. In contrast to most microfluidic glass devices t

  18. Tuning of the selectivity in capillary electrophoresis by cyclodextrins illustrated by the separation of some structurally related phenothiazine

    NARCIS (Netherlands)

    de Boer, T; Bijma, R; Ensing, K


    Cyclodextrins were used to affect the selectivity of the capillary electrophoresis system in the separation of 10 widely used phenothiazines. It was shown that the addition of cyclodextrins substantially improved the selectivity. The effect of temperature and cyclodextrin concentration was studied o

  19. Screening for the presence of drugs in serum and urine using different separation modes of capillary electrophoresis

    NARCIS (Netherlands)

    Boone, C.M; Douma, J.W; Franke, J.P.; de Zeeuw, R.A; Ensing, K


    Capillary electrophoresis (CE) is a modern separation technique that has some distinct advantages for toxicological analysis, such as a high efficiency, fast analysis, flexibility, and complementary separation mechanisms to chromatographic methods. CE can be applied in various modes, which each have

  20. Rapid mutation detection in complex genes by heteroduplex analysis with capillary array electrophoresis. (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Esteban-Cardeñosa, Eva; Lastra, Enrique; García-Girón, Carlos; Miner, Cristina


    Mutational analysis of large multiexon genes without prevalent mutations is a laborious undertaking that requires the use of a high-throughput scanning technique. The Human Genome Project has enabled the development of powerful techniques for mutation detection in large multiexon genes. We have transferred heteroduplex analysis (HA) by conformation-sensitive gel electrophoresis of the two major breast cancer (BC) predisposing genes, BRCA1 and BRCA2, to a multicapillary DNA sequencer in order to increase the throughput of this technique. This new method that we have called heteroduplex analysis by capillary array electrophoresis (HA-CAE) is based on the use of multiplex-polymerase chain reaction (PCR), different fluorescent labels and HA in a 16-capillary DNA sequencer. To date, a total of 114 different DNA sequence variants (19 insertions/deletions and 95 single-nucleotide substitutions - SNS) of BRCA1 and BRCA2 from 431 unrelated BC families have been successfully detected by HA-CAE. In addition, we have optimized the multiplex-PCR conditions for the colorectal cancer genes MLH1 and MSH2 in order to analyze them by HA-CAE. Both genes have been amplified in 13 multiplex groups, which contain the 35 exons, and their corresponding flanking intronic sequences. MLH1 and MSH2 have been analyzed in nine hereditary nonpolyposis colorectal cancer patients, and we have found six different DNA changes: one complex deletion/insertion mutation in MLH1 exon 19 and another five SNS. Only the complex mutation and one SNS may be classified as cancer-prone mutations. Our experience has revealed that HA-CAE is a simple, fast, reproducible and sensitive method to scan the sequences of complex genes.

  1. Characterisation of Crevice and Pit Solution Chemistries Using Capillary Electrophoresis with Contactless Conductivity Detector

    Directory of Open Access Journals (Sweden)

    Robert J.K. Wood


    Full Text Available The ability to predict structural degradation in-service is often limited by a lack of understanding of the evolving chemical species occurring within a range of different microenvironments associated with corrosion sites. Capillary electrophoresis (CE is capable of analysing nanolitre solution volumes with widely disparate concentrations of ionic species, thereby producing accurate and reliable results for the analysis of the chemical compositions found within microenvironment corrosion solutions, such as those found at crevice and pit corrosion sites. In this study, CE with contactless conductivity detection (CCD has been used to characterize pitting and crevice corrosion solution chemistries for the first time. By using the capillary electrophoresis with contactless conductivity detection (CE-CCD system, direct and simultaneous detection of seven metal cations (Cu2+, Ni2+, Fe3+, Fe2+, Cr3+, Mn2+, and Al3+ and chloride anions was achieved with a buffer solution of 10 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium hydroxide at pH 4 using a pre-column complexation method. The detection limits obtained for the metal cations and chloride anions were 100 and 10 ppb, respectively. The CE-CCD methodology has been demonstrated to be a versatile technique capable of speciation and quantifying the ionic species generated within artificial pit (a pencil electrode and crevice corrosion geometries for carbon steels and nickel-aluminium bronze, thus allowing the evolution of the solution chemistry to be assessed with time and the identification of the key corrosion analyte targets for structural health monitoring.

  2. Self-assembled and covalently linked capillary coating of diazoresin and cyclodextrin-derived dendrimer for analysis of proteins by capillary electrophoresis. (United States)

    Yu, Bing; Chi, Ming; Han, Yuxing; Cong, Hailin; Tang, Jianbin; Peng, Qiaohong


    Self-assembled and covalently linked capillary coatings of cyclodextrin-derived (CD) dendrimer were prepared using photosensitive diazoresin (DR) as a coupling agent. Layer by layer (LBL) self-assembled DR/CD-dendrimer coatings based on ionic bonding was fabricated first on the inner surface of capillary, and subsequently converted into covalent bonding after treatment with UV light through a unique photochemistry reaction of DR. Protein adsorption on the inner surface of capillary was suppressed by the DR/CD-dendrimer coating, and thus a baseline separation of lysozyme (Lys), myoglobin (Mb), bovine serum albumin (BSA) and ribonuclease A (RNase A) was achieved using capillary electrophoresis (CE). Compared with the bare capillary, the DR/CD-dendrimer covalently linked capillary coatings showed excellent protein separation performance with good stability and repeatability. Because of the replacement of highly toxic and moisture sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide an environmentally friendly and simple way to prepare the covalently coated capillaries for CE.

  3. A robust method for iodine status determination in epidemiological studies by capillary electrophoresis. (United States)

    de Macedo, Adriana Nori; Teo, Koon; Mente, Andrew; McQueen, Matthew J; Zeidler, Johannes; Poirier, Paul; Lear, Scott A; Wielgosz, Andy; Britz-McKibbin, Philip


    Iodine deficiency is the most common preventable cause of intellectual disabilities in children. Global health initiatives to ensure optimum nutrition thus require continuous monitoring of population-wide iodine intake as determined by urinary excretion of iodide. Current methods to analyze urinary iodide are limited by complicated sample pretreatment, costly infrastructure, and/or poor selectivity, posing restrictions to large-scale epidemiological studies. We describe a simple yet selective method to analyze iodide in volume-restricted human urine specimens stored in biorepositories by capillary electrophoresis (CE) with UV detection. Excellent selectivity is achieved when using an acidic background electrolyte in conjunction with dynamic complexation via α-cyclodextrin in an unmodified fused-silica capillary under reversed polarity. Sample self-stacking is developed as a novel online sample preconcentration method to boost sensitivity with submicromolar detection limits for iodide (S/N ≈ 3, 0.06 μM) directly in urine. This assay also allows for simultaneous analysis of environmental iodide uptake inhibitors, including thiocyanate and nitrate. Rigorous method validation confirmed good linearity (R(2) = 0.9998), dynamic range (0.20 to 4.0 μM), accuracy (average recovery of 93% at three concentration levels) and precision for reliable iodide determination in pooled urine specimens over 29 days of analysis (RSD = 11%, n = 87).

  4. Tudy on drug displacement interactions by capillary electrophoresis-frontal analysis

    Institute of Scientific and Technical Information of China (English)

    Zhou Dawei; Li Famei


    The interaction between 18-methyl norethindrone and ketoprofen,including the displacement of ketoprofen from human serum albumin binding sites,was investigated by the capillary electrophoresis-frontal analysis method (CE-FA)at room temperature.A very large sample plug was introduced hydrostatically into the capillary(65 cm x 50 μm i.d.;effective length of 35 cm)over 80 s at a height difference of 11 cm.The working conditions for CE-FA separation are as follows:operating voltage,10 kV;running buffer,67 mmol.L-1 phosphate,pH 7.4.The unbound ketoprofen concentration was directly measured from the height of the frontal peak.When the concentration of 18-methyl norethindrone was increased from 0 to 200 μmol/L,the unbound ketoprofen concentration was found to increase from 22.4 to 26.4 μmol/L at 100 μmol/L total ketoprofen concentration and from 82.1 to 106.2 μmol/L at 200 μmol/L total ketoprofen concentration.From these data,it may be deduced that the administration of high concentration of 18-methyl norethindrone can displace ketoprofen from its secondary binding site.

  5. Capillary electrophoresis in the evaluation of ischemic injury: simultaneous determination of purine compounds and glutathione. (United States)

    Carlucci, F; Tabucchi, A; Biagioli, B; Sani, G; Lisi, G; Maccherini, M; Rosi, F; Marinello, E


    An understanding of tissue energy metabolism and antioxidant status is of major interest in the field of organ preservation for transplantation. Nucleotide and glutathione are indicators of cell damage occurring during ischemia and reperfusion. A high performance capillary electrophoresis (HPCE) method with UV detection (185 nm) for the simultaneous analysis of intracellular free ribonucleotides, nucleosides, bases and glutathione (oxidized and reduced form) in myocardial tissues is described. The method does not involve thiol derivatization. The separations were carried out in an uncoated fused-silica capillary, 60 cm long, 52.5 cm to detector, 75 microm ID, with 20 mM Na-borate buffer, pH 10.00, at 20 kV voltage and reading at 185 nm. Injection was hydrostatic for 12 s and total analysis time was 20 min. The technique enables optimum separation of all the compounds examined and has a resolution similar to that of HPLC analysis, with the advantage of fast simultaneous measurement of cell nucleotide metabolism and redox state, not possible with HPLC.

  6. Analyses of Phytohormones in Coconut (Cocos Nucifera L. Water Using Capillary Electrophoresis-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Swee Ngin Tan


    Full Text Available Capillary electrophoresis (CE coupled with mass spectrometry (MS or tandem mass spectrometry (MS/MS is reported as an alternative and potentially useful method for the simultaneous analysis of various classes of phytohormones with diversified structures, including indole-3-acetic acid (IAA, indole-3-butyric acid (IBA, abscisic acid (ABA, gibberellic acid (GA, zeatin (Z, N6-benzyladenine (BA, α-naphthaleneacetic acid (NAA and 2,4-dichlorophenoxyacetic acid (2,4-D. The key to the CE-MS/MS analysis was based on electroosmotic flow reversal using a cationic polymer-coated capillary. Under optimum conditions, a baseline separation of eight phytohormones was accomplished within 30 min using 60 mM ammonium formate/formic acid buffer of pH 3.8 with −20 kV as the separation voltage. The accessibility of MS/MS together with the characterization by migration properties obtained by CE allows for the development of CE-MS/MS as an emerging potential method for the analysis of different classes of phytohormones in a single run. The utility of the CE-MS/MS method was demonstrated by the comprehensive screening of phytohormones in coconut (Cocos nucifera L. water after pre-concentration and purification through solid-phase extraction (SPE cartridge. IAA, ABA, GA and Z were detected and quantified in the purified coconut water extract sample.

  7. Multiresidue analysis of phenylurea herbicides in environmental waters by capillary electrophoresis using electrochemical detection. (United States)

    Chicharro, M; Bermejo, E; Sánchez, A; Zapardiel, A; Fernandez-Gutierrez, A; Arraez, D


    A rapid multiresidue method has been developed for the analysis of seven phenylurea herbicides in the presence of two s-triazines in environmental waters. A simple end-column electrochemical detector was used in combination with a commercially-available capillary electrophoresis instrument with UV detection. The determination of phenylurea pesticides using micellar electrokinetic capillary chromatography with electrochemical detection represents the first such determination that has been reported. In both detection systems, linear ranges were obtained for the seven phenylurea herbicides at concentrations lower than 2.0x10(-5) mol l(-1), in 0.020 mol l(-1) phosphoric acid at pH 7.0 and containing 0.020 mol l(-1) of sodium dodecylsulfate, in order to obtain selectivity in the additional separation by a micellar distribution process. Under these conditions a detection limit lower than 5.0x10(-6) mol l(-1) (0.25 pmol of pesticide) was achieved for most of them. The pesticides were resolved in less than 30 min.

  8. Direct determination of amino acids and carbohydrates by high-performance capillary electrophoresis with refractometric detection. (United States)

    Ivano, A R; Nazimov, I V; Lobazov, A P; Popkovich, G B


    This is an initial report to propose a novel approach in high-performance capillary electrophoresis (HPCE) for the direct detection of compounds without natural absorbance in the UV and visible spectral range, such as amino acids and carbohydrates. A refractometry detector with the 2 nl cell (Applied Systems, Minsk, Belarus) was employed to identify amino acids and carbohydrates without derivatization. The first results are provided on separation of seven free amino acids in the phosphate running buffer and three free carbohydrates in the borate-sodium dodecyl sulfate running buffer and detection by refractometer. Fused capillaries of 50 or 75 microm internal diameter and separation voltage (10-23 kV) were applied. Detection limits ranged typically from 10 to 100 fmol and the response was linear over two orders of magnitude for most of the amino acids and carbohydrates. The HPCE system demonstrated good long-term stability and reproducibility with a relative standard deviation, less than 5% for the migration time (n=10).

  9. Analysis of anionic metallized azo and formazan dyes by capillary electrophoresis-mass spectrometry. (United States)

    Poiger, T; Richardson, S D; Baughman, G L


    Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cm x 50 microm uncoated fused-silica capillary and a 5 mM ammonium acetate buffer (pH 9) containing 40% acetonitrile. Excellent separation efficiencies (N = 500,000 plates/column) and low detection limits of 20-50 pg (selected ion monitoring, S/N = 10) were achieved. Mass spectra were acquired at different cone voltages. At low cone voltages (low collision energies), sensitivity was maximized and the mass spectra contained only signals of the (multiply charged) molecular ions and low levels of sodium ion and proton adducts. At higher cone voltages, the 2:1 (ligand:metal) chromium and cobalt dyes showed losses of one of the two dye ligands, accompanied by a reduction of the metal. The copper dyes showed signals due to loss of SO2 and SO3-, but no release of metal. Azo cleavage, otherwise typical of azo dyes, was not observed with the metallized dyes.

  10. Monitoring exocytosis and release from individual mast cells by capillary electrophoresis and UV imaging microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yeung, E.S. [Ames Lab., IA (United States)]|[Iowa State Univ., Ames, IA (United States); Lillard, S.J. [Stanford Univ., CA (United States); McCloskey, M.A. [Iowa State Univ., Ames, IA (United States)


    The complex temporal evolution of on-column exocytotic release of serotonin from individual peritoneal mast cells (RPMCs) was monitored by using capillary electrophoresis and UV imaging microscopy. Laser-induced native fluorescence detection with 275-nm excitation was used, and a detection limit of 1.7 amol (S/N = 3; rms) was obtained for serotonin. A physiological running buffer was used to ensure that the cell remained viable throughout. The secretagogue was polymyxin B sulfate (Pmx). Following the injection of a single mast cell into the capillary, electromigration of Pmx toward and past the cell induced degranulation and release of serotonin. The time course of release was registered in the electropherograms with subsecond resolution. Subsequent introduction of SDS caused the cell to lyse completely and allowed the residual serotonin to be quantified. The average amount of serotonin observed per RPMC was 1.6 {+-} 0.6 fmol; the average percentage of serotonin released was 28 {+-} 14%. Events that are consistent with released serontonin from single submicron granules (250 aL each) were evident, each of which contained an average amount of 5.9 {+-} 3 amol. Alternatively, UV movies can be taken of the entire event to provide temporal and spatial information.

  11. Capillary electrophoresis separation of neutral organic compounds, pharmaceutical drugs, proteins and peptides, enantiomers, and anions

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wei -Liang [Iowa State Univ., Ames, IA (United States)


    Addition of a novel anionic surfactant, namely lauryl polyoxyethylene sulfate, to an aqueous-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the association between analytes and the surfactant. Highly hydrophobic compounds such as polyaromatic hydrocarbons are well separated by this new surfactant. Migration times of analytes can be readily changed over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. Several examples are given, including the separation of four methylbenz[a]anthracene isomers and the separation of normal and deuterated acetophenone. The effect of adding this new surfactant to the acidic electrolyte was also investigated. Incorporation of cetyltrimethylammonium bromide in the electrolyte is shown to dynamically coat the capillary and reverse electroosmotic flow. Chiral recognition mechanism is studied using novel synthetic surfactants as chiral selectors, which are made from amino acids reacting with alkyl chloroformates. A satisfactory separation of both inorganic and organic anions is obtained using electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. The effect of various salts on electrophoretic and electroosmotic mobility is further discussed. Several examples are given under high-salt conditions.

  12. Capillary electrophoresis micro X-ray fluorescence: a tool for benchtop elemental analysis. (United States)

    Miller, Thomasin C; Joseph, Martha R; Havrilla, George J; Lewis, Cris; Majidi, Vahid


    A new tool was developed for separation and elemental detection by interfacing a simple capillary electrophoresis (CE) apparatus, constructed using a thin-walled fused-silica capillary, with a benchtop energy-dispersive micro X-ray fluorescence (MXRF) system. X-ray excitation and detection of the separated analytes was done using an EDAX Eagle II micro X-ray fluorescence system equipped with a polycapillary Rh target excitation source and a SiLi detector. It was demonstrated that this prototype system could be used for the separation and detection of species containing two different metals from one another, specifically Cu and Co. Free Co could also be separated from Co bound to cyanocobalamin (vitamin B-12). Two organic compounds were also separated from one another, a large biological protein, ferritin, from a small biological organic, cyanocobalamin. Preliminary average detection limits obtained on this system were on the order of 10(-)(4) M and compared favorably to those reported for the similar technique of CE-synchrotron XRF. CEMXRF allows for nondestructive, simultaneous, on-line, benchtop elemental analysis for chemical speciation applications.

  13. Capillary electrophoresis methods for the determination of covalent polyphenol-protein complexes. (United States)

    Trombley, John D; Loegel, Thomas N; Danielson, Neil D; Hagerman, Ann E


    The bioactivities and bioavailability of plant polyphenols including proanthocyanidins and other catechin derivatives may be affected by covalent reaction between polyphenol and proteins. Both processing conditions and gastrointestinal conditions may promote formation of covalent complexes for polyphenol-rich foods and beverages such as wine. Little is known about covalent reactions between proteins and tannin, because suitable methods for quantitating covalent complexes have not been developed. We established capillary electrophoresis methods that can be used to distinguish free protein from covalently bound protein-polyphenol complexes and to monitor polyphenol oxidation products. The methods are developed using the model protein bovine serum albumin and the representative polyphenol (-)epigallocatechin gallate. By pairing capillaries with different diameters with appropriate alkaline borate buffers, we are able to optimize resolution of either the protein-polyphenol complexes or the polyphenol oxidation products. This analytical method, coupled with purification of the covalent complexes by diethylaminoethyl cellulose chromatography, should facilitate characterization of covalent complexes in polyphenol-rich foods and beverages such as wine.

  14. Multi-Site N-glycan mapping study 1: Capillary electrophoresis – laser induced fluorescence (United States)

    Szekrényes, Ákos; Park, SungAe Suhr; Santos, Marcia; Lew, Clarence; Jones, Aled; Haxo, Ted; Kimzey, Michael; Pourkaveh, Shiva; Szabó, Zoltán; Sosic, Zoran; Feng, Peng; Váradi, Csaba; de l'Escaille, François; Falmagne, Jean-Bernard; Sejwal, Preeti; Niedringhaus, Thomas; Michels, David; Freckleton, Gordon; Hamm, Melissa; Manuilov, Anastasiya; Schwartz, Melissa; Luo, Jiann-Kae; van Dyck, Jonathan; Leung, Pui-King; Olajos, Marcell; Gu, Yingmei; Gao, Kai; Wang, Wenbo; Wegstein, Jo; Tep, Samnang; Guttman, András


    An international team that included 20 independent laboratories from biopharmaceutical companies, universities, analytical contract laboratories and national authorities in the United States, Europe and Asia was formed to evaluate the reproducibility of sample preparation and analysis of N-glycans using capillary electrophoresis of 8-aminopyrene-1,3,6-trisulfonic acid (APTS)-labeled glycans with laser induced fluorescence (CE-LIF) detection (16 sites) and ultra high-performance liquid chromatography (UHPLC, 12 sites; results to be reported in a subsequent publication). All participants used the same lot of chemicals, samples, reagents, and columns/capillaries to run their assays. Migration time, peak area and peak area percent values were determined for all peaks with >0.1% peak area. Our results demonstrated low variability and high reproducibility, both, within any given site as well across all sites, which indicates that a standard N-glycan analysis platform appropriate for general use (clone selection, process development, lot release, etc.) within the industry can be established. PMID:26466659

  15. Analysis of neutral surfactants by non-aqueous capillary electrophoresis using an electroosmotic flow reversal. (United States)

    Desbène, A M; Geulin, L; Morin, C J; Desbène, P L


    The separation of KM 20, that is in fact a mixture of non-ionic surfactants, was carried out by non-aqueous capillary electrophoresis. This complex mixture resulting from the condensation of ethylene oxide with fatty alcohols does not have chromophoric moieties. So, we analysed it after derivatization by means of 3,5-dinitrobenzoyl chloride. The proposed approach is based both on the formation of complexes with alkaline or ammonium cations in methanol and on the utilisation of a positively charged capillary. From a comparative study on the capillary treatment procedure, we used hexadimethrine bromide as electroosmotic flow reverser in order to obtain both repeatable analyses and good resolutions of the largest KM 20 oligomers. Then, among the five cations used to form complexes with KM 20, we pointed out that ammonium cation led to the best resolutions. Moreover, we evidenced that the counter-ion of this cation had a great influence on resolution because it modified the magnitude of electroosmotic flow. Ion pair formation that is more or less strong between ammonium and its counter-ion was involved in this variation of electroosmotic flow. So, we calculated the association constants for various ammonium salts in methanol. Then, using ammonium chloride as background electrolyte, we optimised the concentration of this salt, in methanol, in order to reach the optimal separation of KM 20 oligomers. Thus, a baseline separation was obtained by using 6 x 10(-2) mol/L NH4Cl as running electrolyte. In these conditions, we separated, in about 30 min, more than 30 oligomers of KM 20. The distribution of these oligomers that was determined from the optimal separation, appeared consistent with that obtained from HPLC analyses. Indeed, we determined that the mean ethoxylation number was equal to 18 while its real value is equal to 20.

  16. Determination of Drugs of Abuse in Saliva by Dispersive Liquid-Liquid Microextraction Coupled with Capillary Zone Electrophoresis%分散液相微萃取-毛细管电泳法同时检测唾液中的8种毒品

    Institute of Scientific and Technical Information of China (English)

    孟梁; 王燕燕; 孟品佳; 王彦吉; 张强


    A novel method was developed for the pre-concentration and determination of eight drugs in saliva by dispersive liquid-liquid microextraction (DLLME) coupled with capillary zone electrophoresis with photo diode array detection (CE-PDA). Parameters affecting extraction efficiency were investigated and optimized. In the method, 0. 5 mL isopropyl alcohol containing 41. 0 μL chloroform was rapidly injected into a 5. 0-mL saliva sample. After centrifugation at 4000 r/min for 5 min, the sedimented phase was transferred into a small volume CE auto-sampler vial and evaporated to dryness.The residue was reconstituted in lidocaine hydrochloride (internal standard) aqueous solution and introduced by electrokinetic injection into CE. Under the optimum conditions, linearity of the method was observed for all target analytes in the range from 0. 15 to 6000 μg/L with the correlation coefficient (r) ranging from 0. 9986 to 0. 9994. The LODs (S/N=3) were estimated to be in the range from 0. 055 to 0. 135 μg/L. Excellent repeatability of the extraction (RSD≤4.0%, n=5) was achieved. As high as 555 to 631 fold enrichment factors were achieved. The feasibility of this method was demonstrated by determination of drugs in saliva samples with spiked recoveries in the range of 85. 6~ 99. 4 % (RSD≤5. 1% , n=5). The method was proven to be simple and environmental benign with high enrichment factor and low cost.%建立了分散液相微萃取与毛细管电泳光电二极管阵列检测法检测唾液中的阿片类、苯丙胺类及氯胺酮等8种毒品的新方法.对影响萃取富集效率的因素进行优化:将0.5 mL含有41 μL三氯甲烷的异丙醇混合溶液快速注入到5.0 mL样品溶液中,分散混匀后,以4000 r/min离心 5 min,移取萃取溶剂并以氮气吹干;再用含有内标物的水溶液溶解后供毛细管电泳分析.在优化条件下,富集倍数达555~631倍;各药物在0.15~6000 μg/L浓度范围内存在良好的线性关系,r为0

  17. Protein analysis by membrane preconcentration-capillary electrophoresis: systematic evaluation of parameters affecting preconcentration and separation. (United States)

    Rohde, E; Tomlinson, A J; Johnson, D H; Naylor, S


    Fast and efficient analysis of proteins in physiological fluids is of great interest to researchers and clinicians alike. Capillary electrophoresis (CE) has proven to be a potentially valuable tool for the separation of proteins in specimens. However, a generally acknowledged drawback of this technique is the limited sample volumes which can be loaded onto the CE capillary which results in a poor concentration limit of detection. In addition, matrix components in samples may also interfere with separation and detection of analytes. Membrane preconcentration-CE (mPC-CE) has proved to be effective in overcoming these problems. In this report, we describe the systematic evaluation of parameters affecting on-line preconcentration/clean-up and separation of protein mixtures by mPC-CE. Method development was carried out with a standard mixture of proteins (lysozyme, myoglobin, carbonic anhydrase, and human serum albumin). First, using MALDI-TOF-MS, membrane materials with cation-exchange (R-SO3H) or hydrophobic (C2, C8, C18, SDB) characteristics were evaluated for their potential to retain proteins in mPC cartridges. Hydrophobic membranes were found most suitable for this application. Next, all mPC-CE analysis of protein samples were performed in polybrene coated capillaries and parameters affecting sample loading, washing and elution, such as the composition and volume of the elution solvent were investigated. Furthermore, to achieve optimal mPC-CE performance for the separation of protein mixtures parameters affecting postelution focusing and electrophoresis, including the composition of the background electrolyte and a trailing stacking buffer were varied. Optimal conditions for mPC-CE analysis of proteins using a C2 impregnated membrane preconcentration (mPC) cartridge were achieved with a background electrolyte of 5% acetic acid and 2 mM ammonium acetate, 60 nl of 80% acetonitrile in H2O as an elution solvent, and 60 nl of 0.5% ammonium hydroxide as a trailing

  18. A liquid core waveguide fluorescence detector for multicapillary electrophoresis applied to DNA sequencing in a 91-capillary array. (United States)

    Hanning, A; Westberg, J; Roeraade, J


    A new laser-induced fluorescence (LIF) detector for multicapillary electrophoresis is presented. The detection principle is based on waveguiding of the emitted fluorescence from the point of illumination to the capillary ends by total internal reflection (TIR) and imaging of the capillary ends. The capillaries themselves thus act as liquid core waveguides (LCWs). At the illumination point, the capillaries are arranged in a planar array, which allows clean and efficient illumination with a line-focused laser beam. The capillary ends are rearranged into a small, densely packed two-dimensional array, which is imaged end-on with high light collection efficiency and excellent image quality. Wavelength dispersion is obtained with a single prism. Intercapillary optical crosstalk is less than 0.5%, and rejection of stray light is very efficient. The detector is applied to four-color DNA sequencing by gel electrophoresis in a 91-capillary array, with simple fluorescein and rhodamine dyes as fluorophores. Since the imaged two-dimensional array is so compact, the detector has a high potential for very large-scale multiplexing.

  19. Simultaneous Determination of Levodopa and Its Metabolite in Human Blood by Capillary Electrophoresis with Laser-induced Fluorescence Detection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying-Xue; ZHANG Zhu-Jun; YANG Feng


    A rapid, sensitive and reproducible method is described for the analysis of levodopa and its metabolite dopamine (DA) in human blood. The influence of carbidopa as the inhibitor againist the decarboxylase activity on the metabolism has been also studied. After derivatization in a dark pulsator for 12 h at room temperature, the fluorescein isothiocyanate (FITC) derivative of levodopa and other components were separated by capillary zone electrophoresis (CZE) within 13 min and detected with laser-induced fluorescence (LIF). Under the optimum analysis conditions, the linear range is 3.0×10-8-4.0×10-6 mol/L and 1.0×10-8-2.0×10-6 mol/L for levodopa and DA,respectively. The detection limits of levodopa and DA were 7.8×10-9 mol/L (39.0 amol) and 3.1×10-9 mol/L(15.5 amol), respectively. The method was successfully applied to monitoring the levodopa and DA in human blood after one took tablets orally.

  20. Self-assembled covalent capillary coating of diazoresin/carboxyl fullerene for analysis of proteins by capillary electrophoresis and a comparison with diazoresin/graphene oxide coating. (United States)

    Yu, Bing; Shu, Xi; Cong, Hailin; Chen, Xin; Liu, Huwei; Yuan, Hua; Chi, Ming


    Self-assembled and covalently linked capillary coatings of carboxyl fullerenes (C60-COOH) were prepared using photosensitive diazoresin (DR) as a coupling agent. Layer by layer (LBL) self-assembled DR/C60-COOH coatings based on ionic bonding was fabricated first on the inner surface of silica capillary, and subsequently converted into covalent bonding after treatment with UV light through a unique photochemistry reaction of DR. The covalently bonded coatings had the ability of suppressing protein adsorption on the inner surface of silica capillary, and thus the baseline separation of lysozyme (Lys), cytochrome c (Cyt-c), bovine serum albumin (BSA) and myoglobin (Mb) was achieved within 13min by using capillary electrophoresis (CE). The covalently linked DR/C60-COOH capillary coatings presented good chemical stability and repeatability. The reproducibility of the separation of proteins was less than 1%, 2.5%, and 3.5%, respectively, for run-to-run, day-to-day, capillary-to-capillary, respectively; and the RSD of migration time for the proteins are all less than 2.5% after a continuous 100 times running in a coating column. Compared with DR/graphene oxide (GO) coatings prepared by the same method, the DR/C60-COOH capillary coatings showed excellent protein separation performance due to a self-lubrication based anti-fouling mechanism. Because of the replacement of highly toxic and moisture sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide an environmentally friendly and simple way to prepare the covalently coated capillaries for CE.

  1. Improvement on Simultaneous Determination of Cr(III) and Cr(VI) by Capillary Electrophoresis and Chemiluminescence Detection

    Institute of Scientific and Technical Information of China (English)


    A sensitive method for the simultaneous determination of Cr(III) and Cr(VI) using in-capillary reaction capillary electrophoresis separation and chemiluminescence detection was developed. The procedures were designed as follows: The sample, hydrochloric acid and sodium hydrogen sulfite solution segments were injected sequentially into the capillary. The reaction of Cr(VI) reduced to Cr(III) by HSO3- occurred inside the capillary after applying the running voltage. According to the migration time difference of both Cr(III) ions moving towards to the cathode (detection end), they could be separated and determined. The limits of detection for chromium(III) and chromium(VI) (S/N = 3) were 6.0(10-13 mol/L (12 zmol) and 1.9(10-11 mol/L (380 zmol), respectively.

  2. Automation and integration of polymerase chain reaction with capillary electrophoresis for high throughput genotyping and disease diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, N.


    Genotyping is to detect specific loci in the human genome. These loci provide important information for forensic testing, construction of genetic linkage maps, gene related disease diagnosis and pharmacogenetic research. Genotyping is becoming more and more popular after these loci can be easily amplified by polymerase chain reaction (PCR). Capillary electrophoresis has its unique advantages for DNA analysis due to its fast heat dissipation and ease of automation. Four projects are described in which genotyping is performed by capillary electrophoresis emphasizing different aspects. First, the author demonstrates a principle to determine the genotype based on capillary electrophoresis system. VNTR polymorphism in the human D1S80 locus was studied. Second, the separation of four short tandem repeat (STR) loci vWF, THO1, TPOX and CSF1PO (CTTv) by using poly(ethylene oxide) (PEO) was studied in achieving high resolution and preventing rehybridization of the DNA fragments. Separation under denaturing, non-denaturing conditions and at elevated temperature was discussed. Third, a 250 {micro}m i.d., 365 {micro}m o.d. fused silica capillary was used as the microreactor for PCR. Fourth, direct PCR from blood was studied to simplify the sample preparation for genotyping to minimum.

  3. Affinity in electrophoresis. (United States)

    Heegaard, Niels H H


    The journal Electrophoresis has greatly influenced my approaches to biomolecular affinity studies. The methods that I have chosen as my main tools to study interacting biomolecules--native gel and later capillary zone electrophoresis--have been the topic of numerous articles in Electrophoresis. Below, the role of the journal in the development and dissemination of these techniques and applications reviewed. Many exhaustive reviews on affinity electrophoresis and affinity CE have been published in the last few years and are not in any way replaced by the present deliberations that are focused on papers published by the journal.

  4. Screening for urinary amphetamine and analogs by capillary electrophoretic immunoassays and confirmation by capillary electrophoresis with on-column multiwavelength absorbance detection. (United States)

    Ramseier, A; Caslavska, J; Thormann, W


    This paper characterizes competitive binding, electrokinetic capillary-based immunoassays for screening of urinary amphetamine (A) and analogs using reagents which were commercialized for a fluorescence polarization immunoassay (FPIA). After incubation of 25 microL urine with the reactants, a small aliquot of the mixture is applied onto a fused-silica capillary and unbound fluorescein-labeled tracer compounds are monitored by capillary electrophoresis with on-column laser-induced fluorescence detection. Configurations in presence and absence of micelles were investigated and found to be capable of recognizing urinary D-(+)-amphetamine at concentrations > about 80 ng/mL. Similar responses were obtained for racemic methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA). The electrokinetic immunoassay data suggest that the FPIA reagent kit includes two immunoassay systems (two antibodies and two tracer molecules), one that recognizes MA and MDMA, and one that is geared towards monitoring of A. For confirmation analysis of urinary amphetamines and ephedrines, capillary electrophoresis in a pH 9.2 buffer and multiwavelength UV detection was employed. The suitability of the electrokinetic methods for screening and confirmation is demonstrated via analysis of patient and external quality control urines.

  5. Simplified universal method for determining electrolyte temperatures in a capillary electrophoresis instrument with forced-air cooling. (United States)

    Patel, Kevin H; Evenhuis, Christopher J; Cherney, Leonid T; Krylov, Sergey N


    Temperature increase due to resistive electrical heating is an inherent limitation of capillary electrophoresis (CE). Active cooling systems are used to decrease the temperature of the capillary, but their capacity is limited; and in addition, they leave "hot spots" at the detection interface and at the capillary ends. Until recently, the matter was complicated by the lack of a fast and generic method for temperature determination in efficiently and inefficiently cooled regions of the capillary. Our group recently introduced such a method, termed "Universal Method for determining Electrolyte Temperatures" (UMET). UMET is a probe-less approach that requires only measuring current versus voltage for different voltages and processing the data using an iterative algorithm. Here, we apply UMET to develop a Simplified Universal Method of Temperature Determination (SUMET) for a CE instrument with a forced-air cooling system using an Agilent 7100 CE instrument (Agilent Technologies, Saint Laurent, Quebec, Canada) as an example. We collected a wide set of empirical voltage-current data for a variety of buffers and capillary diameters. We further constructed empirical equations for temperature calculation in efficiently and inefficiently cooled parts of the capillary that require only the data from a single 1-min voltage-current measurement. The equations are specific for the Agilent 7100 CE instrument (Agilent Technologies) but can be applied to all kinds of capillaries and buffers. Similar SUMET approaches can be developed for other CE instruments with forced-air cooling using our approach.

  6. Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry (United States)

    Moini, Mehdi; Rollman, Christopher M.


    We introduce a battery operated capillary electrophoresis electrospray ionization (CE/ESI) source for mass spectrometry with optical isomer separation capability. The source fits in front of low or high resolution mass spectrometers similar to a nanospray source with about the same weight and size. The source has two high voltage power supplies (±25 kV HVPS) capable of operating in forward or reverse polarity modes and powered by a 12 V rechargeable lithium ion battery with operation time of ~10 h. In ultrafast CE mode, in which short narrow capillaries (≤15 μm i.d., 15-25 cm long) and field gradients ≥1000 V/cm are used, peak widths at the base are <1 s wide. Under these conditions, the source provides high resolution separation, including optical isomer resolution in ~1 min. Using a low resolution mass spectrometer (LTQ Velos) with a scan time of 0.07 s/scan, baseline separation of amino acids and their optical isomers were achieved in ~1 min. Moreover, bovine serum albumin (BSA) was analyzed in ~1 min with 56% coverage using the data-dependent MS/MS. Using a high resolution mass spectrometer (Thermo Orbitrap Elite) with 15,000 resolution, the fastest scan time achieved was 0.15 s, which was adequate for CE-MS analysis when optical isomer separation is not required or when the optical isomers were well separated. Figures of merit including a detection limit of 2 fmol and linear dynamic range of two orders of magnitude were achieved for amino acids.

  7. Analysis of Trinitrophenylated Adenosine and Inosine by Capillary Electrophoresis and γ-Cyclodextrin-Enhanced Fluorescence Detection. (United States)

    Stephen, Terilyn K L; Guillemette, Katherine L; Green, Thomas K


    Monitoring molecules such as adenosine (Ado) and inosine (Ino) in the central nervous system has enabled the field of neuroscience to correlate molecular concentrations dynamics to neurological function, behavior, and disease. In vivo sampling techniques are commonly used to monitor these dynamics; however, many techniques are limited by the sensitivity and sample volume requirements of currently available detection methods. Here, we present a novel capillary electrophoresis-laser-induced fluorescence detection (CE-LIF) method that analyzes Ado and Ino by derivatization with 2,4,6-trinitrobenzenesulfonic acid to form fluorescent trinitrophenylated complexes of Ado (TNP-Ado) and Ino (TNP-Ino). These complexes exhibit ∼25-fold fluorescence enhancement upon the formation of inclusion complexes with γ-cyclodextrin (γ-CD). Association constants were determined as 4600 M(-1) for Ado and 1000 M(-1) for Ino by CE-LIF. The structure of the TNP-Ado:γ-CD complex was determined by 2D nuclear magnetic resonance (NMR) spectroscopy. Optimal trinitrophenylation reaction conditions and CE-LIF parameters were determined and resulted in the limit of detection of 1.6 μM for Ado and 4 μM for Ino. Ado and Ino were simultaneously quantified in homogenized rat forebrain samples to illustrate application of the technique. Simulated biological samples, desalted by ultrafiltration in the presence γ-CD, were concentrated on-capillary by large-volume sample stacking (LVSS) to achieve detection limits of 32 and 38 nM for TNP-Ado and TNP-Ino, respectively.

  8. Influence of neutral cyclodextrin concentration on plate numbers in capillary electrophoresis. (United States)

    Seals, T H; Sheng, C; Davis, J M


    A quantitative theory of plate number N in capillary electrophoresis was developed for buffers containing neutral cyclodextrins (CDs) capable of forming inclusion complexes. In the theory, N was modeled by longitudinal diffusion, injection extent, width of the detection window, and the detector time constant. The apparent mobility was modeled as a weighted sum of the mobilities of the free-solution analyte and the inclusion complex. The apparent diffusion coefficient was modeled as a similarly weighted sum. Both the apparent mobility and diffusion coefficient were corrected by functions that compensated for increases of buffer temperature caused by Joule heat. The experimental N's and apparent mobilities of neutral thiourea and of the anions, dansyl D- and L-leucine, dansyl D- and L-aspartic acid, benzoate, and 4-nitrophenolate, were determined in buffers containing from 0 to 15 mM beta-CD. The binding constants, and mobilities and diffusion coefficients of the free-solution analyte and inclusion complex, were calculated as regression coefficients by fitting theory to these determinations. The regression coefficients were shown to have physicochemical meaning, as assessed by literature values, independent measurements, and theoretical predictions. The assessment showed the Nernst-Einstein equation does not relate mobilities and diffusion coefficients at the electrolyte concentration used. The interdependence of mobilities, diffusion coefficients, binding constants, and other dispersion sources was interpreted to evaluate the factors affecting the variation of N with CD concentration. From the interpretation, an approximate equation for N in low-concentration CD buffers was derived. The equation depends on free-solution and inclusion-complex mobilities and diffusion coefficients, the binding constant, the potential difference over the effective capillary length, and the number of plates in a CD-free buffer.

  9. [Determination of gambogic acid in Gamboge by non-aqueous capillary electrophoresis]. (United States)

    Ou, Wanlu; Li, Yujuan; Shi, Dongdong; Qu, Feng


    Gambogic acid (GA), a kind of caged xanthones, has low solubility in water. A non-aqueous capillary electrophoresis (NACE) was established for the determination of GA in Gamboge based on the optimized conditions. The effect of 20% - 60% methanol or acetonitrile spiked in running solution was investigated. The effects of compositions, concentration, pH, additives like β-cyclodextrin in running buffer were thoroughly studied. Applied voltage and applied temperature were also observed. Optimal electrophoretic conditions were as follows: 20 mmol/L sodium borohydride solution (pH 9. 86) containing 40% (v/v) acetonitrile, 10 mmol/L β-cyclodextrin as running buffer, applied voltage of 10 kV, capillary temperature of 30 °C and detection wavelength of 280 nm. The calibration curve had good linearity in the range of 2-2 000 mg/L with the correlation coefficient of 0. 999 6. The limit of quantification (S/N= 3) of the method was 2 mg/L. The quantifications of GA in Gamboge from different producing places including Vietnam, Thailand, Burma, India were 1. 67-472.40 mg/g with the RSD (n= 3) of 1.12% -2.60%. The content of Gamboge from Vietnam is obviously low while the others are high. The recoveries of GA spiked in real samples ranged from 95. 2% to 105. 6%. The method of NACE is simple, efficient and of good reproducibility, can be served as a novel reference to identify and control the quality of Gamboge.

  10. Identification of inorganic improvised explosive devices using sequential injection capillary electrophoresis and contactless conductivity detection. (United States)

    Blanco, Gustavo A; Nai, Yi H; Hilder, Emily F; Shellie, Robert A; Dicinoski, Greg W; Haddad, Paul R; Breadmore, Michael C


    A simple sequential injection capillary electrophoresis (SI-CE) instrument with capacitively coupled contactless conductivity detection (C(4)D) has been developed for the rapid separation of anions relevant to the identification of inorganic improvised explosive devices (IEDs). Four of the most common explosive tracer ions, nitrate, perchlorate, chlorate, and azide, and the most common background ions, chloride, sulfate, thiocyanate, fluoride, phosphate, and carbonate, were chosen for investigation. Using a separation electrolyte comprising 50 mM tris(hydroxymethyl)aminomethane, 50 mM cyclohexyl-2-aminoethanesulfonic acid, pH 8.9 and 0.05% poly(ethyleneimine) (PEI) in a hexadimethrine bromide (HDMB)-coated capillary it was possible to partially separate all 10 ions within 90 s. The combination of two cationic polymer additives (PEI and HDMB) was necessary to achieve adequate selectivity with a sufficiently stable electroosmotic flow (EOF), which was not possible with only one polymer. Careful optimization of variables affecting the speed of separation and injection timing allowed a further reduction of separation time to 55 s while maintaining adequate efficiency and resolution. Software control makes high sample throughput possible (60 samples/h), with very high repeatability of migration times [0.63-2.07% relative standard deviation (RSD) for 240 injections]. The separation speed does not compromise sensitivity, with limits of detection ranging from 23 to 50 μg·L(-1) for all the explosive residues considered, which is 10× lower than those achieved by indirect absorbance detection and 2× lower than those achieved by C(4)D using portable benchtop instrumentation. The combination of automation, high sample throughput, high confidence of peak identification, and low limits of detection makes this methodology ideal for the rapid identification of inorganic IED residues.

  11. CEval: All-in-one software for data processing and statistical evaluations in affinity capillary electrophoresis. (United States)

    Dubský, Pavel; Ördögová, Magda; Malý, Michal; Riesová, Martina


    We introduce CEval software (downloadable for free at that was developed for quicker and easier electrophoregram evaluation and further data processing in (affinity) capillary electrophoresis. This software allows for automatic peak detection and evaluation of common peak parameters, such as its migration time, area, width etc. Additionally, the software includes a nonlinear regression engine that performs peak fitting with the Haarhoff-van der Linde (HVL) function, including automated initial guess of the HVL function parameters. HVL is a fundamental peak-shape function in electrophoresis, based on which the correct effective mobility of the analyte represented by the peak is evaluated. Effective mobilities of an analyte at various concentrations of a selector can be further stored and plotted in an affinity CE mode. Consequently, the mobility of the free analyte, μA, mobility of the analyte-selector complex, μAS, and the apparent complexation constant, K('), are first guessed automatically from the linearized data plots and subsequently estimated by the means of nonlinear regression. An option that allows two complexation dependencies to be fitted at once is especially convenient for enantioseparations. Statistical processing of these data is also included, which allowed us to: i) express the 95% confidence intervals for the μA, μAS and K(') least-squares estimates, ii) do hypothesis testing on the estimated parameters for the first time. We demonstrate the benefits of the CEval software by inspecting complexation of tryptophan methyl ester with two cyclodextrins, neutral heptakis(2,6-di-O-methyl)-β-CD and charged heptakis(6-O-sulfo)-β-CD.

  12. Functionalization and characterization of persistent luminescence nanoparticles by dynamic light scattering, laser Doppler and capillary electrophoresis. (United States)

    Ramírez-García, Gonzalo; d'Orlyé, Fanny; Gutiérrez-Granados, Silvia; Martínez-Alfaro, Minerva; Mignet, Nathalie; Richard, Cyrille; Varenne, Anne


    Zinc gallate nanoparticles doped with chromium (III) (ZnGa1.995O4:Cr0.005) are innovative persistent luminescence materials with particular optical properties allowing their use for in vivo imaging. They can be excited in the tissue transparency window by visible photons and emit light for hours after the end of the excitation. This allows to observe the probe without any time constraints and without autofluorescence signals produced by biological tissues. Modification of the surface of these nanoparticles is essential to be colloidally stable not only for cell targeting applications but also for proper distribution in living organisms. The use of different methods for controlling and characterizing the functionalization process is imperative to better understand the subsequent interactions with biological elements. This work explores for the first time the characterization and optimization of a classic functionalization sequence, starting with hydroxyl groups (ZGO-OH) at the nanoparticle surface, followed by an aminosilane-functionalization intermediate stage (ZGO-NH2) before PEGylation (ZGO-PEG). Dynamic light scattering and laser doppler electrophoresis were used in combination with capillary electrophoresis to characterize the nanoparticle functionalization processes and control their colloidal and chemical stability. The hydrodynamic diameter, zeta potential, electrophoretic mobility, stability over time and aggregation state of persistent luminescence nanoparticles under physiological-based solution conditions have been studied for each functional state. Additionally, a new protocol to improve ZGO-NH2 stability based on a thermal treatment to complete covalent binding of (3-aminopropyl) triethoxysilane onto the particle surface has been optimized. This thorough control increases our knowledge on these nanoparticles for subsequent toxicological studies and ultimately medical application.

  13. Is pulsed electric field still effective for RNA separation in capillary electrophoresis? (United States)

    Li, Zhenqing; Dou, Xiaoming; Ni, Yi; Chen, Qinmiao; Cheng, Shuyi; Yamaguchi, Yoshinori


    Pulsed field capillary electrophoresis (PFCE) is a predominant technique to cope with difficulties in resolving large DNA strands, yet it is still unclear whether pulsed electric field is effective for the separation of higher mass RNA. In this paper we focused on the role of pulsed electric field in large RNA fragments analysis by comparing RNA separation performance in PFCE with that in constant field CE. Separation performance in terms of migration mobility, plate numbers, resolution, and selectivity has been tested for the analysis of RNA from 0.1 to 10.0 kilo nucleotide (knt) under different electrophoretic conditions. Denaturation, important to obtain uniform and identifiable peaks, was accomplished by heating the sample in 4.0M urea prior to analysis and the presence of 4.0M urea in the electrophoresis buffer. Results demonstrate that unlike DNA in PFCE, the pulsed electric field mainly affects the separation performance of RNA between 0.4 and 2.0 knt. The migration mobility of long RNA fragments is not a strong function of modulation depth and pulsed frequency. Moreover, the logarithm of RNA mobility is almost inversely proportional to the logarithm of molecule size up to 6.0 knt with correlation coefficient higher than 0.99 in all the polymer concentrations measured here. Resonance frequency of RNA in PFCE was also observed. While these initial experiments show no distinct advantages of using PFCE for RNA separation, they do take further step toward characterizing the migration behavior of RNA under pulsed field conditions.


    anodically with generally better resolution than is evident for the cathodically-migrating components. Salivary amylase , a troublesome factor in the starch -gel electrophoresis of saliva proteins, does not attack acrylamide gel.

  15. Human neutrophil elastase inhibition studied by capillary electrophoresis with laser induced fluorescence detection and microscale thermophoresis. (United States)

    Syntia, Fayad; Nehmé, Reine; Claude, Bérengère; Morin, Philippe


    Capillary electrophoresis-laser induced fluorescence (CZE-LIF) and microscale thermophoresis (MST) were used for the first time to study the inhibition of human neutrophil elastase (HNE). We recently studied HNE kinetics (Km and Vmax) by developing an in-capillary CZE-LIF assay based on transverse diffusion of laminar flow profiles (TDLFP) for reactant mixing. In this work, the former assay was adapted to monitor HNE inhibition. Two natural well known HNE inhibitors from the triterpene family, ursolic acid and oleanolic acid, were tested to validate the developed assay. Since the solubility of pentacyclic triterpenes in aqueous media where the enzymatic reaction will take place is limited, the effect of DMSO and ethanol on HNE was studied using microscale thermophoresis (MST). An agglomeration of the enzyme was revealed when preparing the inhibitor in 5% (v/v) DMSO. This phenomenon did not occur in the presence of ethanol. Therefore, ethanol was used as inhibitor solvent, at a limited percentage of 20% (v/v). In these conditions and after optimization of the TDLFP approach, the repeatability (RSD on migration times and peak-areas inferior to 2.2%) of the CZE-LIF assay and the sensitivity (LOQ of few nM) were found to be satisfactory for conducting inhibition assays. IC50 values for ursolic and oleanolic acid were successfully determined. They were respectively equal to 5.62±0.10μM (r(2)=0.9807; n=3) and to 8.21±0.23μM (r(2)=0.9887; n=3). Excellent agreement was found between the results obtained by CE and those reported in literature which validates the developed method. Particularly, the CE-based assay is able to rank HNE inhibitors relative to each other. Furthermore, MST technique was used for evaluating HNE interaction with the ursolic acid. Up to 16 capillaries were automatically processed to obtain in one titration experiment the dissociation constant for the HNE-ursolic acid complex. Ki was found to be 2.72±0.66μM (n=3) which is in excellent agreement

  16. Semi-crosslinked polyacrylamides as high-resolution and dynamic self-coating sieving matrices for protein capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin; XU JianDong; XIE Yao; QU Feng; DENG YuLin; GENG LiNa


    This paper describes non-gel capillary sieving electrophoresis employing semi-crosslinked poly-acrylamide as a high performance and low viscous replaceable separation matrix for separation of non-denatured protein separation. Arising from the fine sieving and dynamic coating ability of this polymer, a mixture of basic proteins lysozyme, cytochrome C, ribonuclease A, and trypsin was resolved with excellent reproducibility. Mixing different semi-crosslinked polyacrylamides together further im-proves the separation. The separtion mechanism was analyzed. With network structure developed to an intermediate state between crosslinked gel and linear polymer solutions, these semi-crosslinked polyacrylamide polymers demonstrate a promise as a new class of size sieving separation medium, not only in capillary electrophoresis, but also in microfluidic chip separation schemes.

  17. Separation of iron-free and iron-saturated forms of transferrin and lactoferrin via capillary electrophoresis performed in fused-silica and neutral capillaries. (United States)

    Nowak, Paweł; Śpiewak, Klaudyna; Brindell, Małgorzata; Woźniakiewicz, Michał; Stochel, Grażyna; Kościelniak, Paweł


    A capillary electrophoresis-based method for the cost-effective and high efficient separation of iron-free and iron-saturated forms of two members of transferrin family: transferrin and lactoferrin has been developed. The proposed qualitative method relying on the SDS application allowed us to separate iron-free and iron-saturated forms of these proteins, as well as human serum albumin, used as an internal standard. Owing to the distinct migration times under established conditions, the combination of transferrin and lactoferrin assays within a single analytical procedure was feasible. The performance of the method using a fused-silica capillary has been compared with the results obtained using the same method but performed with the use of a neutral capillary of the same dimensions. Neutral capillary has been used as an alternative, since the comparable resolution has been achieved with a concomitant reduction of the electroosmotic flow. Despite of this fact, the migration of analytes occurred with similar velocity but in opposite order, due to the reverse polarity application. A quantitative method employing fused-silica capillary for iron saturation study has been also developed, to evaluate the iron saturation in commercial preparations of lactoferrin.

  18. Continuous fractionation of a two-component mixture by zone electrophoresis. (United States)

    Zalewski, Dawid R; Gardeniers, Han J G E


    Synchronized continuous-flow zone electrophoresis is a recently demonstrated tool for performing electrophoretic fractionation of a complex sample. The method resembles free flow electrophoresis, but unlike in that technique, no mechanical fluid pumping is required. Instead, fast electrokinetic flow switching is used to produce complex stream patterns, which results in lateral separation of components in a separation chamber. Here a solution is presented which allows for simultaneous collection of two fractions in synchronized continuous-flow zone electrophoresis. The method is demonstrated on a model mixture, with subsequent evaluation of the collected fractions purity by MCE. The necessary theoretical background is provided including both steering schemes and calculations of optimum operating points.

  19. Capillary electrophoresis single-strand conformation polymorphism for the monitoring of gastrointestinal microbiota of chicken flocks. (United States)

    Pissavin, C; Burel, C; Gabriel, I; Beven, V; Mallet, S; Maurice, R; Queguiner, M; Lessire, M; Fravalo, P


    The objective of the present study was to evaluate the capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) to characterize poultry gut microbiota and the ability of this molecular method to detect modifications related to rearing conditions to be used as an epidemiological tool. The V3 region of the 16S rRNA gene was selected as the PCR target. Our results showed that this method provides reproducible data. The microbiota analysis of individuals showed that variability between individual fingerprints was higher for ileum and cloaca than for ceca. However, pooling the samples decreased this variability. To estimate the variability within and between farms, we compared molecular gut patterns of animals from the same hatchery reared under similar conditions and fed the same diet in 2 separate farms. Total aerobic bacteria, coliforms, and lactic acid bacteria were enumerated using conventional bacteriological methods. A significant difference was observed for coliforms present in the ceca and the cloaca depending on the farm. Ileal contents fingerprints were more closely related to those of cloacal contents than to those of ceca contents. When comparing samples from the 2 farms, a specific microbiota was highlighted for each farm. For each gut compartment, the microbiota fingerprints were joined in clusters according to the farm. Thus, this rapid and potentially high-throughput method to obtain gut flora fingerprints is sensitive enough to detect a "farm effect" on the balance of poultry gut microbiota despite the birds being fed the same regimens and reared under similar conditions.

  20. Identification and differentiation of Cryptosporidium species by capillary electrophoresis single-strand conformation polymorphism. (United States)

    Power, Michelle L; Holley, Marita; Ryan, Una M; Worden, Paul; Gillings, Michael R


    Cryptosporidium species generally lack distinguishing morphological traits, and consequently, molecular methods are commonly used for parasite identification. Various methods for Cryptosporidium identification have been proposed, each with their advantages and disadvantages. In this study, we show that capillary electrophoresis coupled with single-strand conformation polymorphism (CE-SSCP) is a rapid, simple and cost-effective method for the identification of Cryptosporidium species and genotypes. Species could be readily differentiated based on the SSCP mobility of amplified 18S rRNA gene molecules. Clones that differed by single-nucleotide polymorphisms could be distinguished on CE-SSCP mobility. Profiles of species known to have heterogenic copies of 18S rRNA gene contained multiple peaks. Cloning and sequencing of Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium fayeri and Cryptosporidium possum genotype 18S rRNA gene amplicons confirmed that these multiple peaks represented type A and type B 18S rRNA gene copies. CE-SSCP provides a reliable and sensitive analysis for epidemiological studies, environmental detection and diversity screening.

  1. High-speed DNA genotyping using microfabricated capillary array electrophoresis chips

    Energy Technology Data Exchange (ETDEWEB)

    Woolley, A.T.; Sensabaugh, G.F.; Mathies, R.A. [Univ. of California, Berkeley, CA (United States)


    Capillary array electrophoresis (CAE) chips have been designed and fabricated with the capacity to rapidly (<160 s) analyze 12 different samples in parallel. Detection of all lanes with 0.3 s temporal resolution was achieved using a laser-excited confocal-fluorescence scanner. The operation and capabilities of these CAE microdevices were first determined by performing electrophoretic separations of pBR322 MspI DNA samples. Genotyping of HLA-H, a candidate gene for the diagnosis of hereditary hemochromatosis, was then performed to demonstrate the rapid analysis of biologically relevant samples. Two-color multiplex fluorescence detection of HLA-H genotypes was accomplished by prelabeling the standard pBR322 MspI DNA ladder with a red emitting bisintercalation dye (butyl TOTIN) and on-column labeling of the HLA-H DNA with thiazole orange. This work establishes the feasibility of using CAE chips for high-speed, high-throughput genotyping. 44 refs., 7 figs.

  2. Principles, Practice, and Evolution of Capillary Electrophoresis as a Tool for Forensic DNA Analysis. (United States)

    Shewale, J G; Qi, L; Calandro, L M


    Capillary electrophoresis (CE) is a versatile and widely used analysis platform with application in diverse areas such as analytical chemistry, chiral separations, clinical, forensics, molecular biology, natural products, organic chemistry, and the pharmaceutical industry. Forensic applications of CE include fragment analysis, DNA sequencing, SNP typing, and analysis of gunshot residues, explosive residues, and drugs. Fragment analysis is a widely used method for short tandem repeat (STR) profiling for human identification (HID) due to the single-base resolution capability of CE. This approach circumvents the tedious and expensive approach of DNA sequencing for STR typing. The high sizing precision, ability to detect fluorescence emitted from multiple dyes, automated electrophoretic runs, and data collection software are key factors in the worldwide adoption of CE as the preferred platform for forensic DNA analysis. The most common CE systems used in forensic DNA analysis include the ABI PRISM® 310, 3100, 3100 Avant, 3130, 3130xl, 3500, and 3500xL Genetic Analyzers (GAs). The 3500 series GAs are developed with features useful for forensic scientists, including a normalization feature for analysis of the data designed to reduce the variation in peak height from instrument to instrument and injection to injection. Other hardware and software features include improved temperature control, radio frequency identification (RFID) tags for monitoring instrument consumables, HID-focused software features, and security and maintenance.

  3. [Determination of penicillin intermediate and three penicillins in milk by high performance capillary electrophoresis]. (United States)

    Tian, Chunqiu; Tan, Huarong; Gao, Liping; Shen, Huqin; Qi, Kezong


    A high performance capillary electrophoresis (HPCE) method was developed for the simultaneous determination of penicillin intermediate and penicillins in milk, including 6-amino-penicillanic acid (6-APA), penicillin G (PEN), ampicillin (AMP) and amoxicillin (AMO). The main parameters including the ion concentration and pH value of running buffer, separation voltage and column temperature were optimized systematically by orthogonal test. The four penicillins (PENs) were baseline separated within 4.5 min with the running buffer of 40 mmol/L potassium dihydrogen phosphate-20 mmol/L borax solution (pH 7.8), separation voltage of 28 kV and column temperature of 30 degrees C. The calibration curves showed good linearity in the range of 1.56 - 100 mg/L, and the correlation coefficients (r2) were between 0.9979 and 0.9998. The average recoveries at three spiked levels were in the range of 84.91% - 96.72% with acceptable relative standard deviations (RSDs) of 1.11% - 9.11%. The method is simple, fast, accurate and suitable for the determination of penicillins in real samples.

  4. Alignment of capillary electrophoresis-mass spectrometry datasets using accurate mass information. (United States)

    Nevedomskaya, Ekaterina; Derks, Rico; Deelder, André M; Mayboroda, Oleg A; Palmblad, Magnus


    Capillary electrophoresis-mass spectrometry (CE-MS) is a powerful technique for the analysis of small soluble compounds in biological fluids. A major drawback of CE is the poor migration time reproducibility, which makes it difficult to combine data from different experiments and correctly assign compounds. A number of alignment algorithms have been developed but not all of them can cope with large and irregular time shifts between CE-MS runs. Here we present a genetic algorithm designed for alignment of CE-MS data using accurate mass information. The utility of the algorithm was demonstrated on real data, and the results were compared with one of the existing packages. The new algorithm showed a significant reduction of elution time variation in the aligned datasets. The importance of mass accuracy for the performance of the algorithm was also demonstrated by comparing alignments of datasets from a standard time-of-flight (TOF) instrument with those from the new ultrahigh resolution TOF maXis (Bruker Daltonics).

  5. Chiral resolution of basic drugs by capillary electrophoresis with new glycosaminoglycans. (United States)

    Tsukamoto, T; Ushio, T; Haginaka, J


    New glycosaminoglycans, fucose-containing glycosaminoglycan (FGAG) and depolymerized holothurian glycosaminoglycan (DHG), were investigated as chiral additives for the separation of drug enantiomers by capillary electrophoresis. The average molecular masses of FGAG and DHG were estimated to be about 59,000 and 14,000, respectively. A variety of basic drug enantiomers were resolved using 10 mM phosphate buffer, pH 5.0, containing 3% FGAG or DHG. Since chiral recognition properties of FGAG and DHG are different, some drug enantiomers were only separated by using FGAG or DHG. With regard to comparison of chiral recognition abilities of FGAG and DHG with other chiral selectors, tolperisone and eperisone enantiomers were not separated with alpha- or beta-cyclodextrin, or heparin as the chiral additives, but were separated with FGAG and DHG. The results obtained reveal that FGAG and DHG are useful as the chiral selectors for separations of drug enantiomers by CE, and that they could be complementarily used with other chiral additives.

  6. Methoxypropylamino β-cyclodextrin clicked AC regioisomer for enantioseparations in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jie; Wang, Yiying; Liu, Yun; Tang, Jian; Tang, Weihua, E-mail:


    Highlights: In this paper, we demonstrate: • The click synthesis of a AC regioisomer cationic cyclodextrin (CD) as chiral selector. • The good enantioselectivities (chiral resolution over 5) for acidic racemates. • The strong chiral recognition of new CD by NMR study. • Baseline enantioseparation of some acidic racemates at CD of 0.5 mM. - Abstract: In this work, a novel methoxypropylamino β-cyclodextrin (β-CD) clicked AC regioisomer, 6{sup A}-4-hydroxyethyl-1,2,3-triazolyl-6{sup C}-3-methoxypropylamino β-cyclodextrin (HETz-MPrAMCD), was synthesized via nucleophilic addition and click chemistry. The chiral separation ability of this AC regioisomer cationic CD was evaluated toward 7 ampholytic and 13 acidic racemates by capillary electrophoresis. Dependence of enantioselectivity and resolution on buffer pH (5.5–8.0) and chiral selector concentration (0.5–7.5 mM) was investigated. Enantioselectivities (α ≥ 1.05) could be achieved for most analytes under optimal conditions except dansyl-DL-noreleucine and dansyl-DL-serine. The highest resolutions for 2-chloromandelic acid p-hydroxymandelic acid were 15.6 and 9.7 respectively. The inclusion complexation between HETz-MPrAMCD and each 3-phenyllactic acid enantiomer was also revealed with nuclear magnetic resonance study.

  7. Review on the development of truly portable and in-situ capillary electrophoresis systems (United States)

    Lewis, A. P.; Cranny, A.; Harris, N. R.; Green, N. G.; Wharton, J. A.; Wood, R. J. K.; Stokes, K. R.


    Capillary electrophoresis (CE) is a technique which uses an electric field to separate a mixed sample into its constituents. Portable CE systems enable this powerful analysis technique to be used in the field. Many of the challenges for portable systems are similar to those of autonomous in-situ analysis and therefore portable systems may be considered a stepping stone towards autonomous in-situ analysis. CE is widely used for biological and chemical analysis and example applications include: water quality analysis; drug development and quality control; proteomics and DNA analysis; counter-terrorism (explosive material identification) and corrosion monitoring. The technique is often limited to laboratory use, since it requires large electric fields, sensitive detection systems and fluidic control systems. All of these place restrictions in terms of: size, weight, cost, choice of operating solutions, choice of fabrication materials, electrical power and lifetime. In this review we bring together and critique the work by researchers addressing these issues. We emphasize the importance of a holistic approach for portable and in-situ CE systems and discuss all the aspects of the design. We identify gaps in the literature which require attention for the realization of both truly portable and in-situ CE systems.

  8. Microfluidic-based metal enhanced fluorescence for capillary electrophoresis by Ag nanorod arrays (United States)

    Xiao, Chenyu; Cao, Zhen; Deng, Junhong; Huang, Zhifeng; Xu, Zheng; Fu, Junxue; Yobas, Levent


    As metal nanorods show much higher metal enhanced fluorescence (MEF) than metal nanospheres, microfluidic-based MEF is first explored with Ag nanorod (ND) arrays made by oblique angle deposition. By measuring the fluorescein isothiocyanate (FITC) solution sandwiched between the Ag NDs and a piece of cover slip, the enhancement factors (EFs) are found as 3.7 ± 0.64 and 6.74 ± 2.04, for a solution thickness at 20.8 μm and 10 μm, respectively. Because of the strong plasmonic coupling between the adjacent Ag NDs, only the emission of the fluorophores present in the three-dimensional NDs array gets enhanced. Thus, the corresponding effective enhancement factors (EEFs) are revealed to be relatively close, 259 ± 92 and 340 ± 102, respectively. To demonstrate the application of MEF in microfluidic systems, a multilayer of SiO2 NDs/Ag NDs is integrated with a capillary electrophoresis device. At a microchannel depth of 10 μm, an enhancement of 6.5 fold is obtained for amino acids separation detection. These results are very encouraging and open the possibility of MEF applications for the Ag ND arrays decorated microchannels. With the miniaturization of microfluidic devices, microfluidic-based MEF by Ag ND arrays will likely find more applications with further enhancement.

  9. Identification of primary amines in Titan tholins using microchip nonaqueous capillary electrophoresis (United States)

    Cable, M. L.; Hörst, S. M.; He, C.; Stockton, A. M.; Mora, M. F.; Tolbert, M. A.; Smith, M. A.; Willis, P. A.


    Titan, the moon of Saturn with a thick atmosphere and an active hydrocarbon-based weather cycle, is considered the best target in the solar system for the study of organic chemistry on a planetary scale. Microfluidic devices that employ liquid phase techniques such as capillary electrophoresis with ultrasensitive laser-induced fluorescence detection offer a unique solution for in situ analysis of complex organics on Titan. We previously reported a protocol for nonaqueous microfluidic analysis of primary aliphatic amines in ethanol, and demonstrated separations of short- and long-chain amines down to -20 °C. We have optimized this protocol further, and used it to analyze Titan aerosol analogues (tholins) generated in two separate laboratories under a variety of different conditions. Ethylamine was a major product in all samples, though significant differences in amine content were observed, in particular for long-chain amines (C12-C27). This work validates microfluidic chemical analysis of complex organics with relevance to Titan, and represents a significant first step in understanding tholin composition via targeted functional group analysis.

  10. Nonionic surfactant enhanced semipermanent coatings for capillary electrophoresis of inorganic anions without use of organic additives. (United States)

    Yao, Lihua; Liu, Qian; Li, Yi; Yao, Shouzhuo


    Separation of inorganic anions by capillary electrophoresis (CE) is usually conducted in co-electroosmotic mode due to the large electrophoretic mobilities of inorganic anions. Semipermanent surfactant coatings have been shown to be effective for CE of inorganic anions due to their strong capability of electroosmotic flow (EOF) manipulation. However, semipermanent coatings often suffer from their unsatisfactory stability. In addition, organic solvent additives are usually required to adjust the selectivity, which also aggravate the degradation of coating. In this work, a novel semipermanent coating consisting of cationic Gemini surfactant 18-10-18 and nonionic surfactant Tween 20 was developed to separate inorganic anions in CE. This coating is easy to prepare and more stable than pure Gemini coating. The introduction of nonionic surfactant in the coating not only suppresses the reversed EOF but can also adjust the selectivity of separation. Good separations of six model anions were achieved, the separation efficiency was as high as 65040-169700 plates/m and the RSDs of the migration times were less than 0.5 and 2.5% for run-to-run and day-to-day assays, respectively. Calibration curves were linear in the range of 0.05-5.0 mM; the detection limits ranged from 20 to 50 μM. More importantly, no organic solvents are required in the background buffer to achieve the satisfactory separations. This guarantees the coating stability and makes the method greener than most of other methods for CE of inorganic anions.

  11. Capillary electrophoresis fingerprinting and spectrophotometric determination of antioxidant potential for classification of Mentha products. (United States)

    Roblová, Vendula; Bittová, Miroslava; Kubáň, Petr; Kubáň, Vlastimil


    In this work aqueous infusions from ten Mentha herbal samples (four different Mentha species and six hybrids of Mentha x piperita) and 20 different peppermint teas were screened by capillary electrophoresis with UV detection. The fingerprint separation was accomplished in a 25 mM borate background electrolyte with 10% methanol at pH 9.3. The total polyphenolic content in the extracts was determined spectrophotometrically at 765 nm by a Folin-Ciocalteu phenol assay. Total antioxidant activity was determined by scavenging of 2,2-diphenyl-1-picrylhydrazyl radical at 515 nm. The peak areas of 12 dominant peaks from CE analysis, present in all samples, and the value of total polyphenolic content and total antioxidant activity obtained by spectrophotometry was combined into a single data matrix and principal component analysis was applied. The obtained principal component analysis model resulted in distinct clusters of Mentha and peppermint tea samples distinguishing the samples according to their potential protective antioxidant effect. Principal component analysis, using a non-targeted approach with no need for compound identification, was found as a new promising tool for the screening of herbal tea products.

  12. Probing the interactions between boronic acids and cis-diol-containing biomolecules by affinity capillary electrophoresis. (United States)

    Lü, Chenchen; Li, Hengye; Wang, Heye; Liu, Zhen


    The affinity of boronic acids to cis-diol-containing biomolecules has found wide applications in many fields, such as sensing, separation, drug delivery, and functional materials. A sound understanding of the binding interactions will greatly facilitate exquisite applications of this chemistry. Although a few analytical tools have been available for the characterization of the interactions, these techniques are associated with some apparent drawbacks, so they are only applicable to a limited range of boronic acids and cis-diol-containing biomolecules. Therefore, a widely applicable method is still greatly needed. In this work, an affinity capillary electrophoresis (ACE) method was established and validated to probe the interactions between boronic acids and cis-diol-containing biomolecules. The method was proven to be applicable to almost all types of cis-diol-containing biomolecules and boronic acids. Based on this method, a quantitative, comparative study on the interactions between 14 boronic acids that have important potentials for application with 5 typical monosaccharides of biological importance was carried out. The findings provided new insights into boronate affinity interactions, particularly the relationship between the binding strength with the molecular structures of the binding species. Besides, effects of pH and temperature on the binding strength were also investigated. This method exhibited several significant advantages, including (1) possibility of simultaneous study of multiple interactions, (2) low requirement on the purity of the binding species, (3) wide applicability, and (4) high accuracy and precision.

  13. Capillary electrophoresis to determine entrapment efficiency of a nanostructured lipid carrier loaded with piroxicam

    Institute of Scientific and Technical Information of China (English)

    Jessica Otarola; Adriana Guillermina Lista; Beatriz Fernández Band; Mariano Garrido


    A simple and fast capillary electrophoresis method has been developed to determine the amount of piroxicam loaded in a drug delivery system based on nanostructured lipid carriers (NLCs). The entrapment efficiency of the nanostructured lipid carrier was estimated by measuring the concentration of drug not entrapped in a suspension of NLC. The influence of different parameters on migration times, peak symmetry, efficiency and resolution was studied; these parameters included the pH of the electrophoretic buffer solution and the applied voltage. The piroxicam peak was obtained with a satisfactory resolution. The separation was carried out using a running buffer composed of 50 mM ammonium acetate and 13.75 mM ammonia at pH 9. The optimal voltage was 20 kV and the cartridge temperature was 20 1C. The corresponding calibration curve was linear over the range of 2.7–5.4 mg/mL of NLC suspension. The reproducibility of migration time and peak area were investigated, and the obtained RSD% values (n ¼ 5) were 0.99 and 2.13, respectively.

  14. Capillary electrophoresis to determine entrapment efficiency of a nanostructured lipid carrier loaded with piroxicam

    Directory of Open Access Journals (Sweden)

    Jessica Otarola


    Full Text Available A simple and fast capillary electrophoresis method has been developed to determine the amount of piroxicam loaded in a drug delivery system based on nanostructured lipid carriers (NLCs. The entrapment efficiency of the nanostructured lipid carrier was estimated by measuring the concentration of drug not entrapped in a suspension of NLC. The influence of different parameters on migration times, peak symmetry, efficiency and resolution was studied; these parameters included the pH of the electrophoretic buffer solution and the applied voltage. The piroxicam peak was obtained with a satisfactory resolution. The separation was carried out using a running buffer composed of 50 mM ammonium acetate and 13.75 mM ammonia at pH 9. The optimal voltage was 20 kV and the cartridge temperature was 20 °C. The corresponding calibration curve was linear over the range of 2.7–5.4 µg/mL of NLC suspension. The reproducibility of migration time and peak area were investigated, and the obtained RSD% values (n=5 were 0.99 and 2.13, respectively.

  15. Quality Analysis of Herbal Medicine Products Prepared from Herba Sarcandrae by Capillary Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-guang; SUN Jin-ying; ZHU De-rong; YUAN Bai-qing; YOU Tian-yan


    A capillary electrophoresis with electrochemical detection(CE-ED)method was developed for the quality analysis of herbal medicine products prepared from the sanle herb of Herba Sarcandrae:Fufang Caoshanhu tablets,Qingrexiaoyanning capsules,and Xuekang oral liquids.Under the optimal analysis conditions,the low detection limit[1.0×10-7mol/L(S/N=3)]and the wide linear range(1.0×10-7-1.0×10-4 mol/L)were obtained for quality standard compound of isofraxidin.The precisions of the peak current and the migration time(as RSDs)for the real sample analysis were 2.0%-2.6%,and 1.2%-1.8%for isofraxidin,respectively.The contents of isofraxidin detected were 15.77 μg/tablet,0.48 mg/capsule,1.2 mg/ampoule(Jiangxi),and 0.44 mg/ampoule(Dalian)for Fufang Canshanhu tablets,Qingrexiao yanning capsules,and Xuekang oral liquids from different manufacturers,respectively.Quality estimate Was conducted by comparing the contents of isofraxidin in the herbal medicine products with the demanded values of Chinese pharmacopeia.In addition,based on their own unique CE-ED profiles(namely,CE-ED electropherograrns)the Xuekang oral liquids from the different manufacturers could be easily identified.

  16. Determination of Nicotine in Tobacco by Capillary Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    SUN Jin-ying; XU Xiao-yu; YU Huan; YOU Tian-yan


    A sensitive,simple and low-cost method based on capillary electrophoresis(CE) with electrochemical(EC) detection at a carbon fiber microdisk electrode(CFE) was developed for the determination of nicotine.Effects of detection potential,concentration and pH value of the phosphate buffer,and injection time as well as separation voltage were investigated.Under the optimized conditions:a detection potential of 1.20 V,40 mmol/L phosphate buffer(pH 2.0),a sample injection time of 10 s at 10 kV and a separation voltage of 16 kV,the linear range obtained was from 5.0× 10 7 mol/L to 1.0× 10-4 mol/L with a correlation coefficient of 0.9989 and the limit of detection(LOD,S/N=3)obtained was 5.0× 10-8 mol/L.The method was also used to determine the nicotine in cigarettes.Nicotine amount ranged from 0.211 mg/g to 0.583 mg/g in the pipe tobacco of seven brands of cigarette and the amount in one cigarette varied from 0.136 mg/cigarette to 0.428 mg/cigarette.

  17. Analysis of ecstasy tablets using capillary electrophoresis with capacitively coupled contactless conductivity detection. (United States)

    Porto, Suely K S S; Nogueira, Thiago; Blanes, Lucas; Doble, Philip; Sabino, Bruno D; do Lago, Claudimir L; Angnes, Lúcio


    A method for the identification of 3,4-methylenedioxymethamphetamine (MDMA) and meta-chlorophenylpiperazine (mCPP) was developed employing capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C(4) D). Sample extraction, separation, and detection of "Ecstasy" tablets were performed in <10 min without sample derivatization. The separation electrolyte was 20 mm TAPS/Lithium, pH 8.7. Average minimal detectable amounts for MDMA and mCPP were 0.04 mg/tablet, several orders of magnitude lower than the minimum amount encountered in a tablet. Seven different Ecstasy tablets seized in Rio de Janeiro, Brazil, were analyzed by CE-C(4) D and compared against routine gas chromatography-mass spectrometry (GC-MS). The CE method demonstrated sufficient selectivity to discriminate the two target drugs, MDMA and mCPP, from the other drugs present in seizures, namely amphepramone, fenproporex, caffeine, lidocaine, and cocaine. Separation was performed in <90 sec. The advantages of using C(4) D instead of traditional CE-UV methods for in-field analysis are also discussed.

  18. Capillary electrophoresis-based immobilized enzyme reactor using particle-packing technique. (United States)

    Liu, Lina; Zhang, Bo; Zhang, Qian; Shi, Yanhong; Guo, Liping; Yang, Li


    A novel method using particle-packing technique to fabricate capillary electrophoresis (CE)-based immobilized enzyme reactor (IMER) was accomplished by utilizing perfusive silica single particles as the frits and large-pore beads as the enzyme supports. The fabrication procedure is rapid and simple; the length and enzyme loading amount of the CE-IMERs could be easily adjusted. Performance and feasibility of the CE-IMERs were investigated using on-line trypsin digestion as the model enzyme reaction. High reproducible on-line enzyme assay was demonstrated with RSD less than 4.1% and 3.8% for peak area and migration time of the substrate and product over 100 consecutive runs, respectively. The enzyme can still maintain the activity for at least 10 days, indicating remarkably stability of the CE-IMERs. The CE-IMERs were successfully applied for accurate analysis of trypsin inhibition as well as on-line digestion of standard proteins (myoglobin and BSA). The present method provides a new interesting alternative to open-tubular and monolithic CE-IMERs, thus expands the application of the CE technique for on-line enzyme assay and analysis and characterization of peptides and proteins.

  19. [Determination of amino acids in honey by capillary electrophoresis with indirect ultraviolet detection]. (United States)

    Zhou, Xianjing; Shi, Yanping


    A method of capillary electrophoresis with indirect ultraviolet (UV) detection was developed for the separation and determination of nine amino acids such as lysine, tryptophan, glutamic acid, etc. The effects of sodium dihydrogen phosphates concentration, pH of buffer and sample injection type and time on the reproducibility and efficiency were investigated. The optimum injection time was 5 s at 5 kPa. The optimum electrophoretic conditions were as follow: 10 mmol/L sodium dihydrogen phosphates (pH 10. 2) containing 0. 5 mmol/L cetrimonium bromide, 20 mmol/L nicotinic acid and 10% (v/v) methanol as running buffer, applied voltage of - 15 kV, detection wavelength of 220 nm. The base line separation of the nine amino acids was achieved successfully within 11 min. The lowest detection limit was 0. 3 mg/L. All of the nine analytes showed good linearities within 1. 0 - 1000 mg/L. The relative standard deviations of migration time and peak area were 0. 64% - 5. 83%. The recoveries of the eight amino acids spiked in a real sample were between 60. 00% and 118.37%. The method was applied in the determination of the amino acids in honey samples from different nectar plants and origins. Prolin, serine and aspartic acid were found in five honey samples, and tryptophan was only found in a litchi honey sample. This method can provide good reference to the evaluation of the quality and nectar origin of honey.

  20. Determination of ranitidine in urine by capillary electrophoresis-electrochemiluminescent detection. (United States)

    Gao, Ying; Tian, Yiling; Sun, Xiuhua; Yin, Xue-Bo; Xiang, Qian; Ma, Ge; Wang, Erkang


    The fast analysis of ranitidine is of clinical importance in understanding its efficiency and a patient's treatment history. In this paper, a novel determination method for ranitidine based on capillary electrophoresis-electrochemiluminescence detection is described. The conditions affecting separation and detection were investigated in detail. End-column detection of ranitidine in 5 mM Ru(bpy)(3)(2+) solution at applied voltage of 1.20 V was performed. Favorable ECL intensity with higher column efficiency was achieved by electrokinetic injection for 10s at 10 kV. The R.S.D. values of ECL intensity and migration time were 6.38 and 1.84% for 10(-4) M and 6.01 and 0.60% for 10(-5) M, respectively. A detection limit of 7 x 10(-8) M (S/N=3) was achieved. The proposed method was applied satisfactorily to the determination of ranitidine in urine in 6 min.

  1. Metabolomics, peptidomics and proteomics applications of capillary electrophoresis-mass spectrometry in Foodomics: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ibáñez, Clara; Simó, Carolina; García-Cañas, Virginia; Cifuentes, Alejandro, E-mail:; Castro-Puyana, María


    Graphical abstract: -- Highlights: •Foodomics allows studying food and nutrition through the application of advanced omics approaches. •CE-MS plays a crucial role as analytical platform to carry out omics studies. •CE-MS applications for food metabolomics, proteomics and peptidomics are presented. -- Abstract: In the current post-genomic era, Foodomics has been defined as a discipline that studies food and nutrition through the application of advanced omics approaches. Foodomics involves the use of genomics, transcriptomics, epigenetics, proteomics, peptidomics, and/or metabolomics to investigate food quality, safety, traceability and bioactivity. In this context, capillary electrophoresis-mass spectrometry (CE-MS) has been applied mainly in food proteomics, peptidomics and metabolomics. The aim of this review work is to present an overview of the most recent developments and applications of CE-MS as analytical platform for Foodomics, covering the relevant works published from 2008 to 2012. The review provides also information about the integration of several omics approaches in the new Foodomics field.

  2. Rapid simultaneous determination of organic acids, free amino acids, and lactose in cheese by capillary electrophoresis. (United States)

    Izco, J M; Tormo, M; Jiménez-Flores, R


    A capillary electrophoresis (CE) method for the simultaneous separation of 11 metabolically important organic acids (oxalic, formic, citric, succinic, orotic, uric, acetic, pyruvic, propionic, lactic, and butyric), 10 amino acids (Asp, Glu, Tyr, Gly, Ala, Ser, Leu, Phe, Lys, and Trp), and lactose has been optimized, validated, and tested in dairy products. Repeatability and linearity were calculated for each compound, with detection limit values as low as 0.2 x 10(-2) mM for citric acid and Gly. The method was applied to analyze yogurt and different varieties of commercial cheeses. This method yielded specific CE patterns for different varieties of cheese. Also, it has been shown to be sensitive enough to measure small changes in composition of some of those compounds in fresh cheese stored under accelerated ripening conditions for 2 d at 32 degrees C (e.g., from 1728.3 +/- 45.0 to 1166.7 +/- 4.5 mg/100 g of DM in the case of lactose, or from 23.5 +/- 0.6 to 76.8 +/- 16.7 mg/100 g of DM in the case of acetic acid).

  3. Capillary Electrophoresis-Mass Spectrometry for the Analysis of Heparin Oligosaccharides and Low Molecular Weight Heparin. (United States)

    Sun, Xiaojun; Lin, Lei; Liu, Xinyue; Zhang, Fuming; Chi, Lianli; Xia, Qiangwei; Linhardt, Robert J


    Heparins, highly sulfated, linear polysaccharides also known as glycosaminoglycans, are among the most challenging biopolymers to analyze. Hyphenated techniques in conjunction with mass spectrometry (MS) offer rapid analysis of complex glycosaminoglycan mixtures, providing detailed structural and quantitative data. Previous analytical approaches have often relied on liquid chromatography (LC)-MS, and some have limitations including long separation times, low resolution of oligosaccharide mixtures, incompatibility of eluents, and often require oligosaccharide derivatization. This study examines the analysis of glycosaminoglycan oligosaccharides using a novel electrokinetic pump-based capillary electrophoresis (CE)-MS interface. CE separation and electrospray were optimized using a volatile ammonium bicarbonate electrolyte and a methanol-formic acid sheath fluid. The online analyses of highly sulfated heparin oligosaccharides, ranging from disaccharides to low molecular weight heparins, were performed within a 10 min time frame, offering an opportunity for higher-throughput analysis. Disaccharide compositional analysis as well as top-down analysis of low molecular weight heparin was demonstrated. Using normal polarity CE separation and positive-ion electrospray ionization MS, excellent run-to-run reproducibility (relative standard deviation of 3.6-5.1% for peak area and 0.2-0.4% for peak migration time) and sensitivity (limit of quantification of 2.0-5.9 ng/mL and limit of detection of 0.6-1.8 ng/mL) could be achieved.

  4. Analysis of Trace Ingredients in Green Tea by Capillary Electrophoresis with Amperometric Detection

    Institute of Scientific and Technical Information of China (English)

    LI Ping; DONG Shu-Qing; WANG Qing-Jiang; FANG Yu-Zhi


    In this paper, four trace ingredients (rutin, gallic acid, quercetin, chlorogenic acid) in green tea were simultaneously determined by capillary electrophoresis coupled with amperometric detection (CE-AD). Effects of several important factors such as the pH and concentration of running buffer, separation voltage, injection time and detection potential were investigated to acquire the optimum conditions. Under the optimum conditions, the analytes could be separated within 20 min at a separation voltage of 18 kV in a 60 mmol/L borate buffer (pH 8.7). A 300 μmdiameter carbon disk electrode generated good responses at 950 mV (vs. SCE) for all analytes. The relationship between the peak currents and concentrations of the analytes was linear over about three orders of magnitude with demonstrated long-term stability and reproducibility with relative standard deviations less than 3% for both migration time and peak current (n=7), which could be successfully used for the determination of the analytes in green tea with satisfactory assay results.

  5. Poly(ethylene glycol)-functionalized polymeric microchips for capillary electrophoresis. (United States)

    Sun, Xuefei; Li, Dan; Lee, Milton L


    Recently, we reported the synthesis, fabrication, and preliminary evaluation of poly(ethylene glycol) (PEG)-functionalized polymeric microchips that are inherently resistant to protein adsorption without surface modification in capillary electrophoresis (CE). In this study, we investigated the impact of cross-linker purity and addition of methyl methacrylate (MMA) as a comonomer on CE performance. Impure poly(ethylene glycol) diacrylate (PEGDA) induced electroosmotic flow (EOF) and increased the separation time, while the addition of MMA decreased the separation efficiency to approximately 25% of that obtained using microchips fabricated without MMA. Resultant improved microchips were evaluated for the separation of fluorescent dyes, amino acids, peptides, and proteins. A CE efficiency of 4.2 x 10(4) plates for aspartic acid in a 3.5 cm long microchannel was obtained. Chiral separation of 10 different D,L-amino acid pairs was obtained with addition of a chiral selector (i.e., beta-cyclodextrin) in the running buffer. Selectivity (alpha) and resolution (R(s)) for D,L-leucine were 1.16 and 1.64, respectively. Good reproducibility was an added advantage of these PEG-functionalized microchips.

  6. Integrating Internal Standards into Disposable Capillary Electrophoresis Devices To Improve Quantification (United States)


    To improve point-of-care quantification using microchip capillary electrophoresis (MCE), the chip-to-chip variabilities inherent in disposable, single-use devices must be addressed. This work proposes to integrate an internal standard (ISTD) into the microchip by adding it to the background electrolyte (BGE) instead of the sample—thus eliminating the need for additional sample manipulation, microchip redesigns, and/or system expansions required for traditional ISTD usage. Cs and Li ions were added as integrated ISTDs to the BGE, and their effects on the reproducibility of Na quantification were explored. Results were then compared to the conclusions of our previous publication which used Cs and Li as traditional ISTDs. The in-house fabricated microchips, electrophoretic protocols, and solution matrixes were kept constant, allowing the proposed method to be reliably compared to the traditional method. Using the integrated ISTDs, both Cs and Li improved the Na peak area reproducibility approximately 2-fold, to final RSD values of 2.2–4.7% (n = 900). In contrast (to previous work), Cs as a traditional ISTD resulted in final RSDs of 2.5–8.8%, while the traditional Li ISTD performed poorly with RSDs of 6.3–14.2%. These findings suggest integrated ISTDs are a viable method to improve the precision of disposable MCE devices—giving matched or superior results to the traditional method in this study while neither increasing system cost nor complexity. PMID:28192985

  7. Simultaneous electrochemiluminescence determination of sulpiride and tiapride by capillary electrophoresis with cyclodextrin additives. (United States)

    Li, Jianguo; Zhao, Fengjuan; Ju, Huangxian


    Sulpiride and tiapride are often used in the treatment of depression, schizophrenia and psychopathology of senescence, gastric or duodenal ulcers and are also partly excreted by kidney. This work developed a simple and sensitive method for their simultaneous monitoring in human urine based on capillary electrophoresis coupled with electrochemiluminescence detection by end-column mode. beta-Cyclodextrin (beta-CD) was used as an additive to the running buffer to obtain the absolute separation of sulpiride and tiapride. Under optimized conditions the proposed method displayed a linear range from 1.0 x 10(-7) to 1.0 x 10(-4) M for both sulpiride and tiapride with the correlation coefficients more than 0.995 (n = 6). Their limits of detection were 1.0 x 10(-8) M (45 amol) and 1.5 x 10(-8) M (68 amol) at a signal to noise ratio of 3, respectively. The relative standard deviations for six determinations of 2.0 microM sulpiride and 3.0 microM tiapride were 1.8 and 2.5%, respectively. For practical application an extract step with ethyl acetate at pH 11 was performed to eliminate the influence of ionic strength in sample. The recoveries of sulpiride and tiapride at different levels in human urine were between 84 and 95%, which showed that the method was valuable in clinical and biochemical laboratories for monitoring sulpiride and tiapride for various purposes.

  8. Synthesis of ino Acid Derived β-Cyclodextrins Used in Chiral Separation by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    戴荣继; 佟斌; 魏征; 顾峻岭; 邓玉林; 李明愉; 傅若农


    Six new kinds of ino 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 ino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Val-β-CD), heptakis{2,6-di-O-[3-L-(1-benzyl carboxyl methyl ino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Phe-β-CD), heptakis{2,6-di-O-[3-(D, L-1-benzyl carboxyl methyl ino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. D,L-Phe-β-CD), heptakis{2,6-di-O-[3-(L-1-hydroxymethyl carboxyl methyl ino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Ser-β-CD), heptakis{2,6-di-O-[3-(L-1-carboxylmethyl carboxyl methyl ino)- 2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Asp-β-CD), heptakis{2,6-di-O-[3-(L-2-carboxyl tetrethylene ino)-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 ino 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.

  9. Determination of phycobiliproteins by capillary electrophoresis with laser-induced fluorescence detection. (United States)

    Viskari, P J; Kinkade, C S; Colyer, C L


    Phycobiliproteins are derived from the photosynthetic apparatus of cyanobacteria and eukaryotic algae. They are composed of a protein backbone to which linear tetrapyrrole chromophores are covalently bound. Furthermore, they are water-soluble highly fluorescent, and relatively stable at room temperature and neutral pH. For this reason, capillary electrophoresis-laser induced fluorescence (CE-LIF) seems the idea method for determination of these important proteins. The effects of buffer additives such as sodium dodecyl sulfate (SDS)and putrescine on the separation of the three major phycobiliprotein types, namely allophycocyanin, phycocyanin, and phycoerythrin, with excitation and emission maxima at 652/660, 615/647, and 565(494)/575 nm, respectively, are considered. Detection limits for these proteins by CE-LIF are some 60-500 times better than by absorbance detection. The development of a fast and sensitive CE-LIF assay such as this is of potential significance to our understand ing of chemical and biological oceanographic processes.

  10. Precise, fast, and flexible determination of protein interactions by affinity capillary electrophoresis: part 3: anions. (United States)

    Xu, Yuanhong; Redweik, Sabine; El-Hady, Deia Abd; Albishri, Hassan M; Preu, Lutz; Wätzig, Hermann


    The binding of physiologically anionic species or negatively charged drug molecules to proteins is of great importance in biochemistry and medicine. Since affinity capillary electrophoresis (ACE) has already proven to be a suitable analytical tool to study the influence of ions on proteins, this technique was applied here for comprehensively studying the influence of various anions on proteins of BSA, β-lactoglobulin, ovalbumin, myoglobin, and lysozyme. The analysis was performed using different selected anions of succinate, glutamate, phosphate, acetate, nitrate, iodide, thiocyanate, and pharmaceuticals (salicylic acid, aspirin, and ibuprofen) that exist in the anionic form at physiological pH 7.4. Due to the excellent repeatability and precision of the ACE measurements, not necessarily strong but significant influences of the anions on the proteins were found in many cases. Different influences in the observed bindings indicated change of charge, mass, or conformational changes of the proteins due to the binding with the studied anions. Combining the mobility-shift and pre-equilibrium ACE modes, rapidity and reversibility of the protein-anion bindings were discussed. Further, circular dichroism has been used as an orthogonal approach to characterize the interactions between the studied proteins and anions to confirm the ACE results. Since phosphate and various anions from amino acids and small organic acids such as succinate or acetate are present in very high concentrations in the cellular environment, even weak influences are certainly relevant as well.

  11. Digitally synchronized LCD projector for multi-color fluorescence excitation in parallel capillary electrophoresis detection. (United States)

    Lin, Shi-Wei; Chang, Chih-Hang; Wu, Dai-Yang; Lin, Che-Hsin


    A simple method is proposed for modulating the excitation light used for multi-color fluorescence detection in a single capillary electrophoresis (CE) channel. In the proposed approach, a low-cost commercial liquid crystal device (LCD) projector with digitally-modulated LCD switches is used to provide the illumination light source and the fluorescence emitted from the CE chip is synchronously detected using an ultraviolet-visible-near infrared (UV-vis-NIR) spectrometer. The modulated light source enables the detection of multiple fluorescence signals within a single CE channel without the need of mechanically switching optical components. In order to enhance the sensing performance of the proposed system, two short-pass filters and one band-pass filter are inserted into the LCD projector to modify the wavelength spectra for fluorescence excitation. With this simple approach, the signal-to-noise (SN) ratio of the fluorescence detection signals is greatly improved by a factor of approximately 22 when detecting Atto647N fluorescent dye. The feasibility of the proposed multi-color CE detection approach is demonstrated by detecting two different samples including a mixed sample comprising FITC, Rhodamine B and Atto647N fluorescent dyes and a bio-sample composed of two ssDNAs labeled with FITC and Cy3, respectively. Results confirm that the digitally-modulated excitation system proposed in this study has significant potential for the parallel analysis of fluorescently-labeled bio-samples using a multi-color detection scheme.

  12. Chemometrics optimization of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection. (United States)

    Zhu, Derong; Li, Xia; Sun, Jinying; You, Tianyan


    This work expanded the knowledge of the use of chemometric experimental design in optimizing of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection. Specially, central composite design was employed for optimizing the three critical electrophoretic variables (Tris-H(3)PO(4) buffer concentration, buffer pH value and separation voltage) using the chromatography resolution statistic function (CRS function) as the response variable. The optimum conditions were established from empirical model: 24.2mM Tris-H(3)PO(4) buffer (pH 2.7) with separation voltage of 15.9 kV. Applying theses conditions, the six antihistamines (carbinoxamine, chlorpheniramine, cyproheptadine, doxylamine, diphenhydramine and ephedrine) could be simultaneous separated in less than 22 min. Our results indicate that the chemometrics optimization method can greatly simplify the optimization procedure for multi-component analysis. The proposed method was also validated for linearity, repeatability and sensitivity, and was successfully applied to determine these antihistamine drugs in urine.

  13. Determination of Active Ingredients of Hawthorn by Capillary Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    TANG Zhu-Xing; ZENG Yi-Kun; ZHOU Yun; ZANG Shu-Liang; HE Pin-Gang; FANG Yu-Zhi


    A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, kaempferol, chlorogenic acid, 4-hydroxybenzoic acid, quercetin and protocatechuic acid in hawthorn for the first time. The effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated. Under the optimum conditions,the analytes could be separated in a 60 mmol·L-1 borate buffer (pH 8.7) within 21 min. A 300 μm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 3×10-8 to2×10-7 g·mL-1 for the analytes. The method has been successfully applied to the analysis of real sample, with satisfactory results.

  14. Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food. (United States)

    Omar, Mei Musa Ali; Elbashir, Abdalla Ahmed; Schmitz, Oliver J


    Simple and inexpensive capillary electrophoresis with UV-detection method (CE-UV) was optimized and validated for determination of six amino acids namely (alanine, asparagine, glutamine, proline, serine and valine) for Sudanese food. Amino acids in the samples were derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-UV analysis. Labeling reaction conditions (100mM borate buffer at pH 8.5, labeling reaction time 60min, temperature 70°C and NBD-Cl concentration 40mM) were systematically investigated. The optimal conditions for the separation were 100mM borate buffer at pH 9.7 and detected at 475nm. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) (RSD%) and accuracy (recovery). Good linearity was achieved for all amino acids (r(2)>0.9981) in the concentration range of 2.5-40mg/L. The LODs in the range of 0.32-0.56mg/L were obtained. Recoveries of amino acids ranging from 85% to 108%, (n=3) were obtained. The validated method was successfully applied for the determination of amino acids for Sudanese food samples.

  15. Enantiodifferentiation of chiral baclofen by β-cyclodextrin using capillary electrophoresis: A molecular modeling approach (United States)

    Suliman, FakhrEldin O.; Elbashir, Abdalla A.


    Using capillary electrophoresis baclofen (BF) enantiomers were separated only in the presence of β-cyclodextrin (βCD) as a chiral selector when added to the background electrolyte. Proton nuclear magnetic resonance and electrospray ionization mass spectrometry (ESI-MS) techniques were used to determine the structure of the BF-βCD inclusion complexes. From the MS data BF was found to form a 1:1 complex with α- and βCD, while the NMR data suggest location of the aromatic ring of BF into the cyclodextrin cavity. A molecular modeling study, using the semiempirical PM6 calculations was used to investigate the mechanism of enantiodifferentiation of BF with cyclodextrins. Optimization of the structures of the complexes by PM6 method indicated that separation is obtained in the presence of β-CD due to a large binding energy difference (ΔΔE) of 46.8 kJ mol-1 between S-BF-βCD and R-BF-βCD complexes. In the case of αCD complexes ΔΔE was 1.3 kJ mol-1 indicating poor resolution between the two enantiomers. Furthermore, molecular dynamic simulations show that the formation of more stable S-BF-βCD complex compared to R-BF-β-CD complex is primarily due to differences in intermolecular hydrogen bonding.

  16. Characterization of microconcentric nebulizer uptake rates for capillary electrophoresis inductively coupled plasma mass spectrometry (United States)

    Yanes, Enrique G.; Miller-Ihli, Nancy J.


    There is demonstrated interest in combining capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICP-MS) for speciation determinations. When self-aspirating nebulizers are used for this application, it is important to offset the suction effect to avoid degradation of the separation. In this study, sample uptake rates for three microconcentric nebulizers of the same model, in combination with a cyclonic spray chamber, were characterized and compared for future utilization in CE-ICP-MS interfaces. The specific model studied was a MicroMist with a nominal uptake rate of 100 μl/min at 1 l/min argon gas flow rate per the manufacturer's specifications. Sample uptake rates at various nebulizer gas flows were measured by aspirating water from a weighed container and calculating the uptake rate in microliter per minute. The nebulizers studied provided good reproducibility from day to day, but a comparison of the different nebulizers reflected a significant difference in performance. A characteristic observed during the study was that uptake rates decreased with increasing nebulizer gas flow. This can be used for sample introduction for CE-ICP-MS. Interestingly, very different performance was observed when comparing the three different nebulizers of the same model. Uptake rates showed strong dependence on argon gas flow rates and the dimensions of the sample uptake tubing.

  17. Determination of gibberellins in soybean using tertiary amine labeling and capillary electrophoresis coupled with electrochemiluminescence detection. (United States)

    Zhu, Guimei; Long, Shihua; Sun, Hao; Luo, Wen; Li, Xia; Hao, Zaibin


    A novel sensitive method based on tertiary amine labeling for the analysis of gibberellins (GAs) by capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection was proposed. GA3 was tagged with 2-(2-aminoethyl)-1-methylpyrrolidine (AEMP) using N, N'-dicyclohexylcarbodiimide (DCC) and 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (HOOBt) as coupling agents in acetonitrile to produce GA3-AEMP-derivative. The GA3-AEMP-derivative was injected into CE by electrokinetic injection and detected by Ru(bpy)3(2+)-based ECL. The parameters affecting derivatization, detection and separation such as concentration of reactants, detection potential, pH and concentration of separation buffer, were investigated in detail. Under optimum conditions, the linear concentration range for GA3 was from 2.0×10(-7) to 1.28×10(-4)M with a correlation coefficient of 0.9997. The detection limit was 8×10(-8)M (S/N=3). The relative standard deviations of migration time, peak intensity and peak area for nine continuous injections of 2.0×10(-5)M GA3-AEMP-derivative were 1.0%, 2.1% and 4.2%, respectively. The developed approach was successfully applied to the determination of total GAs in the stem, leaf and seed of soybean (Glycine max [L.] Merr.) with recoveries in the range from 89.6% to 99.3%.

  18. Capillary electrophoresis with electrochemiluminescent detection for highly sensitive assay of genetically modified organisms. (United States)

    Guo, Longhua; Yang, Huanghao; Qiu, Bin; Xiao, Xueyang; Xue, Linlin; Kim, Donghwan; Chen, Guonan


    A capillary electrophoresis coupled with electrochemiluminescent detection system (CE-ECL) was developed for the detection of polymerase chain reaction (PCR) amplicons. The ECL luminophore, tris(1,10-phenanthroline) ruthenium(II) (Ru(phen)(3)(2+)), was labeled to the PCR primers before amplification. Ru(phen)(3)(2+) was then introduced to PCR amplicons by PCR amplification. Eventually, the PCR amplicons were separated and detected by the homemade CE-ECL system. The detection of a typical genetically modified organism (GMO), Roundup Ready Soy (RRS), was shown as an example to demonstrate the reliability of the proposed approach. Four pairs of primers were amplified by multiple PCR (MPCR) simultaneously, three of which were targeted on the specific sequence of exogenous genes of RRS, and another was targeted on the endogenous reference gene of soybean. Both the conditions for PCR amplification and CE-ECL separation and detection were investigated in detail. Results showed that, under the optimal conditions, the proposed method can accurately identifying RRS. The corresponding limit of detection (LOD) was below 0.01% with 35 PCR cycles.

  19. Simultaneous Detection of Genetically Modified Organisms in a Mixture by Multiplex PCR-Chip Capillary Electrophoresis. (United States)

    Patwardhan, Supriya; Dasari, Srikanth; Bhagavatula, Krishna; Mueller, Steffen; Deepak, Saligrama Adavigowda; Ghosh, Sudip; Basak, Sanjay


    An efficient PCR-based method to trace genetically modified food and feed products is in demand due to regulatory requirements and contaminant issues in India. However, post-PCR detection with conventional methods has limited sensitivity in amplicon separation that is crucial in multiplexing. The study aimed to develop a sensitive post-PCR detection method by using PCR-chip capillary electrophoresis (PCR-CCE) to detect and identify specific genetically modified organisms in their genomic DNA mixture by targeting event-specific nucleotide sequences. Using the PCR-CCE approach, novel multiplex methods were developed to detect MON531 cotton, EH 92-527-1 potato, Bt176 maize, GT73 canola, or GA21 maize simultaneously when their genomic DNAs in mixtures were amplified using their primer mixture. The repeatability RSD (RSDr) of the peak migration time was 0.06 and 3.88% for the MON531 and Bt176, respectively. The RSD (RSDR) of the Cry1Ac peak ranged from 0.12 to 0.40% in multiplex methods. The method was sensitive in resolving amplicon of size difference up to 4 bp. The PCR-CCE method is suitable to detect multiple genetically modified events in a composite DNA sample by tagging their event specific sequences.

  20. On-line concentration of trace genistein by acid barrage stacking in capillary electrophoresis with UV detection

    Institute of Scientific and Technical Information of China (English)

    Hai Yan Feng; Xiang Jun Li; Shu Rong Hou; Na Zheng; Zhong Bo Hu; Zhuo Bin Yuan


    A capillary electrophoresis method with UV detection was developed for high sensitively determining genistein. In this method, the online acid barrage stacking was applied. Four key factors influencing the stacking efficiency were systematically optimized. Genistein can be detected within 5 rain at the concentration of 10 nmol/L, which was 300 times lower than that from conventional hydrodynamic injection. The repeatability, linear range, and limit of detection of the method were investigated with satisfactory result.