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Sample records for capillary electrophoresis method

  1. Capillary electrophoresis systems and methods

    SciTech Connect

    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.

    2011-08-02

    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.

  2. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2000-01-01

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  3. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2004-06-15

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  4. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edwards; Kuhr, Werner G.

    1991-04-09

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  5. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edward S.; Kuhr, Werner G.

    1996-02-20

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  6. Kinetic methods in capillary electrophoresis and their applications

    NASA Astrophysics Data System (ADS)

    Berezovski, Maxim V.; Okhonin, Victor; Petrov, Alex; Krylov, Sergey N.

    2005-09-01

    In recent years, capillary electrophoresis (CE) has been one of rapidly growing analytical techniques to study affinity interactions. Quick analysis, high efficiency, high resolving power, low sample consumption, and wide range of possible analytes make CE an indispensable tool for studies of biomolecules and, in particular, studies of their interactions. In the article, we discuss kinetic methods in CE. The spectrum of proven applications of kinetic CE methods includes: (i) measuring equilibrium and rate constants of protein-ligand interaction from a single experiment, (ii) quantitative affinity analyses of proteins, (iii) measuring temperature in CE, (iv) studying thermochemistry of affinity interactions, and (v) kinetic selection of ligands from combinatorial libraries. We demonstrate that new kinetic CE method can serve as a "Swiss army knife" in the development and utilization of oligonucleotide aptamers. Uniquely, they can facilitate selection of smart aptamers - aptamers with pre-defined binding parameters. We believe that further development of kinetic CE methods will provide a variety of methodological schemes for high-throughput screening of combinatorial libraries for affinity probes and drug candidates using CE as a universal instrumental platform.

  7. Electrochemical methods in conjunction with capillary and microchip electrophoresis.

    PubMed

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

    2012-12-01

    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.

  8. Capillary electrophoresis as an orthogonal technique in HPLC method validation.

    PubMed

    Jimidar, M Ilias; De Smet, Maurits; Sneyers, Rudy; Van Ael, Willy; Janssens, Willy; Redlich, Dirk; Cockaerts, Paul

    2003-01-01

    High-performance liquid chromatography is usually used to assay the main compound and organic impurity content of drug substance and drug product during pharmaceutical development. A crucial validation parameter of these methods is specificity--the ability to unequivocally assess the analyte in the presence of component expected to be present. Typically, these include impurities, degradation products, and matrices. Besides adequate chromatographic separation with sufficient selectivity, additional 2- or 3-D spectroscopic or chromatographic tools are frequently necessary for this purpose. In our current practice, HPLC is used with ultraviolet photodiode array detection and on-line mass spectrometry (LC-UVDAD-MS) during the assessment of specificity. Although this approach is very powerful and can solve the majority of problems, separation of isomers of the main compound is still difficult. Since HPLC usually cannot offer the required selectivity and because of the similar molecular weights, structural isomers are not specifically detected using LC-MS. Capillary electrophoresis, on the other hand, offers high separation efficiency and can be applied as an adjunct to HPLC. Therefore, a set of highly selective CE methods is used orthogonally in the specificity assessment of HPLC methods.

  9. Capillary zone electrophoresis

    SciTech Connect

    Jorgenson, J.W.; Lukacs, K.D.

    1983-10-21

    Zone electrophoresis in capillaries is a technique complementary to electrophoresis in supporting media, and each approach has its own particular advantages. Efficient heat transfer from small-diameter capillaries permits use of unusually high voltages, resulting in both high resolution and rapid analysis. Capillaries also seem well suited for automation. Our present electromigration injection technique is relatively straightforward and should be simple to automate. Capillaries are reusable, which is an advantage over gels. On-line electronic detection permits good quantification, further enhancing possibilities for fully automatic operation. The greatest obstacle to further development and utilization of capillaries is the requirement of extremely sensitive detectors, and more types of detectors with higher sensitivity are greatly needed. A better understanding of capillary surface modification will also be important, both for improved capillary surface deactivation and for better control over electroosmotic flow. Capillaries should provide an ideal system in which to explore nonaqueous separation media. The prospects for nonaqueous media in electrophoresis are similar to those in electrochemistry, and capillaries should prove an excellent system in which to begin their study. 18 refs., 8 figs.

  10. Conformation-sensitive capillary electrophoresis.

    PubMed

    Ashton, Emma Jane

    2011-01-01

    Conformation-sensitive capillary electrophoresis (CSCE) is a rapid, high-throughput screening method that can be applied to any region of a genome for detection of sequence variants. Slab gel-based conformation-sensitive gel electrophoresis was first described by Ganguly et al., and the transfer from slab gels to capillaries for higher throughput was reported by Rozycka et al. CSCE is based on the principle that DNA homoduplexes and heteroduplexes migrate at different rates during electrophoresis under mildly denaturing conditions. Fragments showing an altered peak morphology compared to the wild type are then sequenced to determine the precise nature of the sequence variant detected.

  11. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Li, Q.; Lu, X.

    1998-04-21

    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.

  12. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Chang, H.T.; Fung, E.N.; Li, Q.; Lu, X.

    1996-12-10

    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.

  13. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Li, Qingbo; Lu, Xiandan

    1998-04-21

    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.

  14. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.; Li, Qingbo; Lu, Xiandan

    1996-12-10

    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.

  15. Microfabricated capillary electrophoresis chip and method for simultaneously detecting multiple redox labels

    DOEpatents

    Mathies, Richard A.; Singhal, Pankaj; Xie, Jin; Glazer, Alexander N.

    2002-01-01

    This invention relates to a microfabricated capillary electrophoresis chip for detecting multiple redox-active labels simultaneously using a matrix coding scheme and to a method of selectively labeling analytes for simultaneous electrochemical detection of multiple label-analyte conjugates after electrophoretic or chromatographic separation.

  16. Integrated multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Tan, Hongdong

    2002-05-14

    The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provided.

  17. Derivatization in Capillary Electrophoresis.

    PubMed

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    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). PMID:27645730

  18. Liposome behavior in capillary electrophoresis.

    PubMed

    Roberts, M A; Locascio-Brown, L; Maccrehan, W A; Durst, R A

    1996-10-01

    The behavior of liposomes in capillary electrophoresis is studied for the purpose of developing a potential method for characterizing liposomes prepared for use in industrial and analytical applications. This study characterizes the electrophoretic behavior of liposomes under various conditions to provide information about electrophoretic mobility and liposome-capillary surface interactions. The results of this method are compared with the results obtained using traditional laser light-scattering methods to obtain size information about liposome preparations. Additionally, reactions of liposomes and the surfactant n-octyl-β-d-glucopyranoside are performed off-line in bulk solution experiments and on-line in the capillary. Automated delivery of lysis agents by multiple electrokinetic injections is demonstrated as a general method for inducing on-capillary reactions between liposomes and other reagents. Furthermore, some preliminary evidence on the use of liposomes as a hydrophobic partitioning medium for analytical separations is presented.

  19. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    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.

  20. Capillary Electrophoresis in Metabolomics.

    PubMed

    Maier, Tanja Verena; Schmitt-Kopplin, Philippe

    2016-01-01

    Metabolomics is an analytical toolbox to describe (all) low-molecular-weight compounds in a biological system, as cells, tissues, urine, and feces, as well as in serum and plasma. To analyze such complex biological samples, high requirements on the analytical technique are needed due to the high variation in compound physico-chemistry (cholesterol derivatives, amino acids, fatty acids as SCFA, MCFA, or LCFA, or pathway-related metabolites belonging to each individual organism) and concentration dynamic range. All main separation techniques (LC-MS, GC-MS) are applied in routine to metabolomics hyphenated or not to mass spectrometry, and capillary electrophoresis is a powerful high-resolving technique but still underused in this field of complex samples. Metabolomics can be performed in the non-targeted way to gain an overview on metabolite profiles in biological samples. Targeted metabolomics is applied to analyze quantitatively pre-selected metabolites. This chapter reviews the use of capillary electrophoresis in the field of metabolomics and exemplifies solutions in metabolite profiling and analysis in urine and plasma. PMID:27645748

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

    SciTech Connect

    Garner, T.

    1993-07-01

    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.

  2. Multivariate optimization of capillary electrophoresis methods: a critical review.

    PubMed

    Orlandini, Serena; Gotti, Roberto; Furlanetto, Sandra

    2014-01-01

    In this article a review on the recent applications of multivariate techniques for optimization of electromigration methods, is presented. Papers published in the period from August 2007 to February 2013, have been taken into consideration. Upon a brief description of each of the involved CE operative modes, the characteristics of the chemometric strategies (type of design, factors and responses) applied to face a number of analytical challenges, are presented. Finally, a critical discussion, giving some practical advices and pointing out the most common issues involved in multivariate set-up of CE methods, is provided.

  3. Analysis of Small Ions with Capillary Electrophoresis.

    PubMed

    Aulakh, Jatinder Singh; Kaur, Ramandeep; Malik, Ashok Kumar

    2016-01-01

    Small inorganic ions are easily separated through capillary electrophoresis because they have a high charge-to-mass ratio and suffer little from some of the undesired phenomenon affecting higher molecular weight species like adsorption to the capillary wall, decomposition, and precipitation. This chapter is focused on the analysis of small ions other than metal ions using capillary electrophoresis. Methods are described for the determination of ions of nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, and iodine. PMID:27645739

  4. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

    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.

  5. Uniform Laser Excitation And Detection In Capillary Array Electrophoresis System And Method.

    DOEpatents

    Li, Qingbo; Zhou, Songsan; Liu, Changsheng

    2003-10-07

    A capillary electrophoresis system comprises capillaries positioned in parallel to each other forming a plane. The capillaries are configured to allow samples to migrate. A light source is configured to illuminate the capillaries and the samples therein. This causes the samples to emit light. A lens is configured to receive the light emitted by the samples and positioned directly over a first group of the capillaries and obliquely over a second group of the capillaries. The light source is further configured to illuminate the second group of capillaries more than the first group of the capillaries such that amount of light received by the lens from the first group of capillaries is substantially identical to amount of light received from the second group of capillaries when an identical amount of the samples is migrating through the first and second group capillaries.

  6. Determination of acidity constants by the capillary electrophoresis internal standard method. IV. Polyprotic compounds.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

    2013-03-01

    The IS-CE method is developed for pK(a) determination of polyprotic compounds. In this method, the internal standard (IS) and the polyprotic test compound are injected into the capillary electrophoresis (CE) system in buffers with appropriate pH. The pH of the buffers is not externally measured, but determined inside the capillary from the mobilities of the internal standards. Then the pK(a) values of the polyprotic compounds are obtained by fitting its mobilities to the in situ pH values. The method is faster than the classical CE method (a diprotic compound can be done in less than 15 min), and also than other methods like potentiometric and spectrophotometric titrations. The method has been successfully applied to 20 polyprotic test compounds of different chemical nature, including compounds with extreme or very close pK(a) values.

  7. Biomedical applications of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    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.

  8. Comparison of capillary electrophoresis with traditional methods to analyse bovine whey proteins.

    PubMed

    Kinghorn, N M; Norris, C S; Paterson, G R; Otter, D E

    1995-05-12

    The separation of the four major whey proteins by sodium dodecyl sulphate (SDS)-capillary gel electrophoresis (CGE) is described. Whilst commercially purified whey proteins could be analysed using the recommended protocol, the more complex nature of an acid whey and a reconstituted whey protein concentrate (WPC) powder necessitated considerable refinement of the CGE sample buffer. Individual whey proteins in the acid whey and WPC samples were then also separated and quantitated using capillary zone electrophoresis, polyacrylamide gel electrophoresis (PAGE) and HPLC methods and the results were compared. The values obtained for alpha-lactalbumin (alpha-Lac) and beta-lactoglobulin (beta-Lg) were consistent throughout the various methods, although size-exclusion HPLC, SDS-PAGE and SDS-CGE could not separate the two beta-Lg variants or the glycosylated form of alpha-Lac from the beta-Lg. There was considerable variation in the values for the bovine serum albumin and immunoglobulin determined by the different methods and it was concluded that none of the methods could satisfactorily quantitate all four whey proteins.

  9. Capillary electrophoresis in metallodrug development.

    PubMed

    Holtkamp, Hannah; Hartinger, Christian G

    2015-09-01

    Capillary electrophoresis (CE) is a separation method based on differential migration of analytes in electric fields. The compatibility with purely aqueous separation media makes it a versatile tool in metallodrug research. Many metallodrugs undergo ligand exchange reactions that can easily be followed with this method and the information gained can even be improved by coupling the CE to advanced detectors, such as mass spectrometers. This gives the method high potential to facilitate the development of metallodrugs, especially when combined with innovative method development and experimental design. PMID:26547417

  10. DNA typing by capillary electrophoresis

    SciTech Connect

    Zhang, N.

    1997-10-08

    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.

  11. Capillary Electrophoresis in Wine Science.

    PubMed

    Coelho, Christian; Bagala, Franck; Gougeon, Régis D; Schmitt-Kopplin, Philippe

    2016-01-01

    Capillary electrophoresis appeared to be a powerful and reliable technique to analyze the diversity of wine compounds. Wine presents a great variety of natural chemicals coming from the grape berry extraction and the fermentation processes. The first and more abundant after water, ethanol has been quantified in wines via capillary electrophoresis. Other families like organic acids, neutral and acid sugars, polyphenols, amines, thiols, vitamins, and soluble proteins are electrophoretically separated from the complex matrix.Here, we will focus on the different methodologies that have been employed to conduct properly capillary electrophoresis in wine analysis.Two examples informing on wine chemistry obtained by capillary electrophoresis will be detailed. They concern polyphenol analysis and protein profiling. The first category is a well-developed quantitative approach important for the quality and the antioxidant properties conferred to wine. The second aspect involves more research aspects dealing with microbiota infections in the vineyard or in the grape as well as enological practices. PMID:27645750

  12. Potentials and Method Improvements of Capillary Zone Electrophoresis for Use in Spelt Breeding Programs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Capillary zone electrophoresis (CZE) in acidic buffer systems is capable of separating cereal storage proteins based on similar separation principles as classical acidic polyacrylamide gel electrophoresis. However, it is faster, its resolution is distinctly higher and data evaluation is much simpler...

  13. Capillary electrophoresis methods for the analysis of antimalarials. Part I. Chiral separation methods.

    PubMed

    Amin, N'cho Christophe; Blanchin, Marie-Dominique; Aké, Michèle; Fabre, Huguette

    2012-11-16

    This paper presents an overview on the current status of enantiomeric and diastereomeric separations of chiral antimalarials and derivatives by capillary electrophoresis (CE). The wide variety of chiral selectors which have been employed to resolve successfully antimalarial enantiomers: oligosaccharides (cyclodextrins, oligomaltodextrins), neutral (amylose, dextrin and dextran) and charged (chondroitin sulfate, heparin, dextran sulfate) polysaccharides and proteins are reviewed. Cyclodextrins were the most employed. Chiral additives added to the background electrolyte often facilitated separations of quinine/quinidine and cinchonine/cinchonidine diastereomers. However, in a few cases, using micellar electrokinetic capillary chromatography or non aqueous CE, resolution of diastereomers could be achieved without additives. Quantitative applications of CE to the quality control of antimalarial drugs and their analysis in biological and food matrices are presented.

  14. [Quantitative determination of morphine in opium powder by addition and correlation method using capillary electrophoresis].

    PubMed

    Sun, Guo-xiang; Miao, Ju-ru; Wang, Yu; Sun, Yu-qing

    2002-01-01

    The morphine in opium powder has been quantitatively determined by addition and correlation method (ACM), in which capillary zone electrophoresis was applied, and the average recovery was 100.6%. The relative standard deviation (RSD) of migration time was not more than 2.4%, the RSD of relative migration time was not more than 1.1%, and the RSD of the relative area was not more than 0.51%. Meanwhile, the contrast test has been done by the calibration curve method with an internal standard correlation. The content of morphine in opium powder determined by ACM was the same as that by using the calibration curve method with an internal standard correlated. The study shows that ACM is simple, quick and accurate.

  15. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

    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

  16. The development and application of capillary electrophoresis methods for food analysis.

    PubMed

    Frazier, R A; Ames, J M; Nursten, H E

    1999-10-01

    Capillary electrophoresis (CE) offers the analyst a number of key advantages for the analysis of the components of foods. CE offers better resolution than, say, high-performance liquid chromatography (HPLC), and is more adept at the simultaneous separation of a number of components of different chemistries within a single matrix. In addition, CE requires less rigorous sample cleanup procedures than HPLC, while offering the same degree of automation. However, despite these advantages, CE remains under-utilized by food analysts. Therefore, this review consolidates and discusses the currently reported applications of CE that are relevant to the analysis of foods. Some discussion is also devoted to the development of these reported methods and to the advantages/disadvantages compared with the more usual methods for each particular analysis. It is the aim of this review to give practicing food analysts an overview of the current scope of CE.

  17. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species

    PubMed Central

    Jernigan, Alice; Hestekin, Christa

    2015-01-01

    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. PMID:26101693

  18. A simpler and faster capillary electrophoresis method for determination of mianserin enantiomers in human serum.

    PubMed

    Grodner, Błazej; Pachecka, Jan

    2006-01-01

    A stereospecific sample stacking capillary zone electrophoresis method is described for determination of S(+) and R(-) enantiomers of mianserin (1,2,3,4,10,14b-hexahydro-2-methyldibenzo[c,f]pyrazino[1,2-a]azepine) in human serum. The enantiomers of mianserin were extracted from human serum in one step extraction procedure using the mixture n-heptane:ethyl acetate (80:20, v/v). After separation of layers and freezing at -28 degrees C the organic layer was decanted and evaporated under a stream of nitrogen. The sample was dissolved in the mixture: water:methanol:acetonitrile (2:1:1, v/v/v). Separation was conducted in an aqueous solution of phosphoric acid (0.075M) adjusted to pH = 3.0 with concentrated triethylamine, and 2 mmole/L of 2-hydroxypropyl-beta-cyclodextrin. The analytes were measured by ultraviolet detection at 214 nm after separation on a Fused-Silica eCAP capillary. Clozapine was used as an internal standard. Recovery of the enantiomers from serum ranged from 82.94 to 90.37%. Total time of analysis was 49 minutes, whereas the other methods needed up to 100 minutes.

  19. [Selection of back-ground electrolyte in capillary zone electrophoresis by triangle and tetrahedron optimization methods].

    PubMed

    Sun, Guoxiang; Song, Wenjing; Lin, Ting

    2008-03-01

    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.

  20. Determination of the dissociation constants of sulfonated azo dyes by capillary zone electrophoresis and spectrophotometry methods.

    PubMed

    Pérez-Urquiza, M; Beltrán, J L

    2001-05-11

    The dissociation constants of 10 sulfonated azo dyes, six of the most common food colours used as additives (Food Yellow 4, Food Yellow 3, Food Red 9, Food Red 7, Food Red 17 and Food Blue 5), and four commonly used as textile dyes (Acid Orange 7, Acid Orange 12, Acid Red 26 and Acid Red 88), have been determined by two different systems, one by using capillary electrophoresis (CE) with diode array detection and the other by using UV-visible absorption spectrophotometry, which has been used as reference method to obtain the pKa values. The pKa values obtained by CE were determined in two ways, first on the basis of the electrophoretic mobilities (calculated from the migration times), and after we propose a new methodology, in which the dissociation constants are determined from the spectra corresponding to the maxima of electrophoretic peaks. The pKa values obtained by using these CE methods have been compared with those obtained by using the spectrophotometric method. The results show that the pKa values obtained by the CE proposed method are in general closer to the reference values than those obtained from the electrophoretic mobilities. Moreover, the proposed method retains the advantages of CE, as the possibility of working with small amounts of sample, despite its purity.

  1. A capillary electrophoresis method to study postmortem proteolysis in relation to pork tenderness.

    PubMed

    Kristensen, Lars; Therkildsen, Margrethe; Ertbjerg, Per

    2003-09-24

    Identification of factors that determine meat tenderness is of high priority. The aim of this work was to develop a method that can detect indicators of proteolysis in meat early postmortem. The method was validated on pork samples. A procedure to detect differences of extractable lower molecular weight compounds after a prerigor freeze/thaw cycle of meat was developed using capillary electrophoresis. The procedure was able to separate 39 peaks in the electropherograms. Eight of the peaks were correlated (P < 0.1) to Warner-Bratzler shear forces 1 day postmortem (WB1). A multiple linear regression model explained 69% of the variation in WB1 using the areas of four peaks. Several of the peaks used in modeling WB1 were related to the at-slaughter activity of the calpain system. The results presented show that the developed method is able to detect indicators of proteolysis and tenderness at an early time point after slaughter. The method is a new tool intended for studies regarding the mechanisms of postmortem proteolysis and tenderization.

  2. Capillary electrophoresis in food authenticity.

    PubMed

    Kvasnicka, Frantisek

    2005-06-01

    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.

  3. A Direct and Rapid Method to Determine Cyanide in Urine by Capillary Electrophoresis

    PubMed Central

    Zhang, Qiyang; Maddukuri, Naveen; Gong, Maojun

    2015-01-01

    Cyanides are poisonous chemicals that widely exist in nature and industrial processes as well as accidental fires. Rapid and accurate determination of cyanide exposure would facilitate forensic investigation, medical diagnosis, and chronic cyanide monitoring. Here, a rapid and direct method was developed for the determination of cyanide ions in urinary samples. This technique was based on an integrated capillary electrophoresis system coupled with laser-induced fluorescence (LIF) detection. Cyanide ions were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) and a primary amine (glycine) for LIF detection. Three separate reagents, NDA, glycine, and cyanide sample, were mixed online, which secured uniform conditions between samples for cyanide derivatization and reduced the risk of precipitation formation of mixtures. Conditions were optimized; the derivatization was completed in 2-4 minutes, and the separation was observed in 25 s. The limit of detection (LOD) was 4.0 nM at 3-fold signal-to-noise ratio for standard cyanide in buffer. The cyanide levels in urine samples from smokers and non-smokers were determined by using the method of standard addition, which demonstrated significant difference of cyanide levels in urinary samples from the two groups of people. The developed method was rapid and accurate, and is anticipated to be applicable to cyanide detection in waste water with appropriate modification. PMID:26342870

  4. Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food.

    PubMed

    Omar, Mei Musa Ali; Elbashir, Abdalla Ahmed; Schmitz, Oliver J

    2017-01-01

    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.

  5. A direct and rapid method to determine cyanide in urine by capillary electrophoresis.

    PubMed

    Zhang, Qiyang; Maddukuri, Naveen; Gong, Maojun

    2015-10-01

    Cyanides are poisonous chemicals that widely exist in nature and industrial processes as well as accidental fires. Rapid and accurate determination of cyanide exposure would facilitate forensic investigation, medical diagnosis, and chronic cyanide monitoring. Here, a rapid and direct method was developed for the determination of cyanide ions in urinary samples. This technique was based on an integrated capillary electrophoresis system coupled with laser-induced fluorescence (LIF) detection. Cyanide ions were derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) and a primary amine (glycine) for LIF detection. Three separate reagents, NDA, glycine, and cyanide sample, were mixed online, which secured uniform conditions between samples for cyanide derivatization and reduced the risk of precipitation formation of mixtures. Conditions were optimized; the derivatization was completed in 2-4min, and the separation was observed in 25s. The limit of detection (LOD) was 4.0nM at 3-fold signal-to-noise ratio for standard cyanide in buffer. The cyanide levels in urine samples from smokers and non-smokers were determined by using the method of standard addition, which demonstrated significant difference of cyanide levels in urinary samples from the two groups of people. The developed method was rapid and accurate, and is anticipated to be applicable to cyanide detection in waste water with appropriate modification.

  6. Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food.

    PubMed

    Omar, Mei Musa Ali; Elbashir, Abdalla Ahmed; Schmitz, Oliver J

    2017-01-01

    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. PMID:27507479

  7. A capillary electrophoresis method for studying apo, holo, recombinant, and subunit dissociated ferritins.

    PubMed

    Zhao, Z; Malik, A; Lee, M L; Watt, G D

    1994-04-01

    A capillary electrophoresis (CE) method is described for detecting and quantitating apo and holo ferritins from horse spleen (HoSF), rat liver (RLF), recombinant human light chain (rLF), recombinant human heavy chain (rHF), site-directed variants of human light chain, and Azotobacter vinelandii bacterial ferritin (AVBF). This procedure is carried out at pH 8.2, where the ferritin molecules are associated into their 24-mers. Protein mobilities as expressed as elution times were clearly resolved and could be used to distinguish one ferritin type from another, providing a means for detecting and quantitating various ferritin species in purified or partially purified states. Measurements of these and other ferritins were also conducted at pH 2.0, where dissociation into their respective subunits occurs. For HoSF and RLF, the individual L and H subunits were resolved and their relative concentrations were determined by integrating the areas of the elution peaks. HoSF gave 89.8% L and 10.2% H and RLF gave 70.7% L and 29.3% H, while rLF, rHF, and AVBF gave only a single subunit, all in agreement with reported values obtained by polyacrylamide gel electrophoresis. CE of HoSF, containing increasing amounts of iron in the interior, in general, showed that protein mobilities increased, reached a plateau, and then slowly decreased with increasing core size, although buffer effects altered this CE behavior to some extent. Such results indicate that species formed early during core formation have individual iron atoms present and differ from those formed later in which the oligomeric iron core has formed.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Capillary electrophoresis for drug analysis

    NASA Astrophysics Data System (ADS)

    Lurie, Ira S.

    1999-02-01

    Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

  9. A rapid sample screening method for authenticity control of whiskey using capillary electrophoresis with online preconcentration.

    PubMed

    Heller, Melina; Vitali, Luciano; Oliveira, Marcone Augusto Leal; Costa, Ana Carolina O; Micke, Gustavo Amadeu

    2011-07-13

    The present study aimed to develop a methodology using capillary electrophoresis for the determination of sinapaldehyde, syringaldehyde, coniferaldehyde, and vanillin in whiskey samples. The main objective was to obtain a screening method to differentiate authentic samples from seized samples suspected of being false using the phenolic aldehydes as chemical markers. The optimized background electrolyte was composed of 20 mmol L(-1) sodium tetraborate with 10% MeOH at pH 9.3. The study examined two kinds of sample stacking, using a long-end injection mode: normal sample stacking (NSM) and sample stacking with matrix removal (SWMR). In SWMR, the optimized injection time of the samples was 42 s (SWMR42); at this time, no matrix effects were observed. Values of r were >0.99 for the both methods. The LOD and LOQ were better than 100 and 330 mg mL(-1) for NSM and better than 22 and 73 mg L(-1) for SWMR. The CE-UV reliability in the aldehyde analysis in the real sample was compared statistically with LC-MS/MS methodology, and no significant differences were found, with a 95% confidence interval between the methodologies.

  10. A rapid sample screening method for authenticity control of whiskey using capillary electrophoresis with online preconcentration.

    PubMed

    Heller, Melina; Vitali, Luciano; Oliveira, Marcone Augusto Leal; Costa, Ana Carolina O; Micke, Gustavo Amadeu

    2011-07-13

    The present study aimed to develop a methodology using capillary electrophoresis for the determination of sinapaldehyde, syringaldehyde, coniferaldehyde, and vanillin in whiskey samples. The main objective was to obtain a screening method to differentiate authentic samples from seized samples suspected of being false using the phenolic aldehydes as chemical markers. The optimized background electrolyte was composed of 20 mmol L(-1) sodium tetraborate with 10% MeOH at pH 9.3. The study examined two kinds of sample stacking, using a long-end injection mode: normal sample stacking (NSM) and sample stacking with matrix removal (SWMR). In SWMR, the optimized injection time of the samples was 42 s (SWMR42); at this time, no matrix effects were observed. Values of r were >0.99 for the both methods. The LOD and LOQ were better than 100 and 330 mg mL(-1) for NSM and better than 22 and 73 mg L(-1) for SWMR. The CE-UV reliability in the aldehyde analysis in the real sample was compared statistically with LC-MS/MS methodology, and no significant differences were found, with a 95% confidence interval between the methodologies. PMID:21662238

  11. The method of single-nucleotide variations detection using capillary electrophoresis and molecular beacons.

    PubMed

    Wang, Jinhui; Wang, Wei; Liu, Yanhong; Duo, Libo; Huang, Lijuan; Jiang, Xiaofeng

    2009-09-01

    We demonstrate that single-nucleotide variations in a DNA sequence can be detected using capillary electrophoresis (CE) and molecular beacons (MBs). In this method, the region surrounding the site of a nucleotide variation was amplified in a polymerase chain reaction, then hybridize PCR products with each of MBs. The sequences of the PCR products are different at the site of 2,044 in exon of interleukin (IL)-13 which to be identified. Through denaturation, the PCR product became single strand and hybridized with the completely complementary MB. The MB-target duplexes were separated using CE and solution-based fluorescence techniques. The results show that in each reaction a fluorescent response was elicited from the molecular beacon which was perfectly complementary to the amplified DNA, but not from the other MB whose probe sequence mismatched the target sequence. The method of CE based on MBs is able to identify single-nucleotide variations in a DNA sequence and can discriminate the genotyping of the SNP between the homo- and heteroduplexes of DNA fragments.

  12. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  13. Ionic Liquids in Capillary Electrophoresis.

    PubMed

    Holzgrabe, Ulrike; Wahl, Joachim

    2016-01-01

    Recently, a great interest was drawn toward ionic liquids (ILs) in analytical separation techniques. ILs possess many properties making them excellent additives in capillary electrophoresis (CE) background electrolytes (BGE). The most important property is the charge of the dissolved ions in BGE enabling the cations to interact with deprotonated silanol groups on the capillary surface and thereby modifying the electroosmotic flow (EOF). Ionic and/or proton donor-acceptor interactions between analyte and IL are possible interactions facilitating new kinds of separation mechanisms in CE. Further advantages of ILs are the high conductivity, the environmentally friendliness, and the good solubility for organic and inorganic compounds. The most commonly used ILs in capillary electrophoresis are dialkylimidazolium-based ILs, whereas for enantioseparation a lot of innovative chiral cations and anions were investigated.ILs are reported to be additives to a normal CE background electrolyte or the sole electrolyte in CE, nonaqueous CE (NACE), micellar electrokinetic chromatography (MEKC), and in enantioseparation. An overview of applications and separation mechanisms reported in the literature is given here, in addition to the enantioseparation of pseudoephedrine using tetrabutylammonium chloride (TBAC) as IL additive to an ammonium formate buffer containing β-cyclodextrin (β-CD). PMID:27645735

  14. Enantiomer Separations by Capillary Electrophoresis.

    PubMed

    Scriba, Gerhard K E; Harnisch, Henrik; Zhu, Qingfu

    2016-01-01

    Capillary electrophoresis (CE) is a versatile and flexible technique for analytical enantioseparations. This is due to the large variety of chiral selectors as well as the different operation modes including electrokinetic chromatography, micellar electrokinetic chromatography, and microemulsion electrokinetic chromatography. The chiral selector, which is added to the background electrolyte, represents a pseudostationary phase with its own electrophoretic mobility allowing a variety of different separation protocols. The present chapter briefly addresses the basic fundamentals of CE enantioseparations as well as the most frequently applied chiral selectors and separation modes. The practical example illustrates the separation of the enantiomers of a positively charged analyte using native and charged cyclodextrin derivatives as chiral selectors. PMID:27645742

  15. Microfluidic flow counterbalanced capillary electrophoresis.

    PubMed

    Xia, Ling; Dutta, Debashis

    2013-04-01

    Flow counterbalanced capillary electrophoresis (FCCE) offers a powerful approach to realizing difficult charge based separations in compact microchip devices with application of relatively small electrical voltages. The need for dynamically controlling the pressure-gradient in the FCCE column however presents a significant challenge in implementing this technique on the microchip platform. In this article, we report the use of a simple on-chip pumping unit that allows precise introduction of a periodic pressure-driven backflow into a microfluidic separation channel enabling an FCCE analysis. The backflow in our device was produced by fabricating a shallow segment (0.5 μm deep) downstream of the analysis column (5 μm deep) and applying an electric field across it. A mismatch in the electroosmotic transport rate at the interface of this segment was shown to yield a pressure-gradient that could reverse the flow of the analyte bands without inverting the direction of the electric field. Although such a pressure-gradient also led to additional band broadening in the system, overall, the separation resolution of our device was observed to improve with an increasing number of back-and-forth sample passes through the analysis channel. For our current design, the corresponding improvement in the effective separation length was as much as 52% of the actual distance travelled by the chosen FITC-labeled amino acid samples. The reported device is well suited for further miniaturization of the FCCE method to the nanofluidic length scale which likely would improve its performance, and is easily integrable to other analytical procedures on the microchip platform for lab-on-a-chip applications. PMID:23420375

  16. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    PubMed

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

    The term nonaqueous capillary electrophoresis (NACE) commonly refers to capillary electrophoresis with purely nonaqueous background electrolytes (BGE). Main advantages of NACE are the possibility to analyze substances with very low solubility in aqueous media as well as separation selectivity that can be quite different in organic solvents (compared to water)-a property that can be employed for manipulation of separation selectivities. Mass spectrometry (MS) has become more and more popular as a detector in CE a fact that applies also for NACE. In the present chapter, the development of NACE-MS since 2004 is reviewed. Relevant parameters like composition of BGE and its influence on separation and detection in NACE as well as sheath liquid for NACE-MS are discussed. Finally, an overview of the papers published in the field of NACE-MS between 2004 and 2014 is given. Applications are grouped according to the field (analysis of natural products, biomedical analysis, food analysis, analysis of industrial products, and fundamental investigations). PMID:27645734

  17. Iohexol in serum determined by capillary electrophoresis.

    PubMed

    Shihabi, Z K; Constantinescu, M S

    1992-10-01

    Iohexol, a nonionic compound used as a contrast medium for angiography and as a measure of the glomerular filtration rate, was quantified in serum by capillary electrophoresis. Comparable results were obtained for serum samples deproteinized with acetonitrile or analyzed directly after 50-fold dilution with borate buffer. Serum samples were electrophoresed for 2.6 min at 12 kV in a borate buffer with detection at 254 nm and with 3-isobutyl-1-methylxanthine as internal standard. Acetonitrile deproteinization gave a greater sensitivity than did sample dilution. Between-run CVs were between 4.7% and 6.7%, and within-run CVs were between 2.5 and 3.2%. Analytical recoveries were 95-105%. Results of the method compared well with those by high-performance liquid chromatography (slope 0.96, intercept 0.005 g/L). This method demonstrates the potential of capillary electrophoresis for rapid and simple quantification of small molecules.

  18. Determination of binding constants by affinity capillary electrophoresis, electrospray ionization mass spectrometry and phase-distribution methods

    PubMed Central

    Chen, Zhi; Weber, Stephen G.

    2008-01-01

    Many methods for determining intermolecular interactions have been described in the literature in the past several decades. Chief among them are methods based on spectroscopic changes, particularly those based on absorption or nuclear magnetic resonance (NMR) [especially proton NMR (1H NMR)]. Recently, there have been put forward several new methods that are particularly adaptable, use very small quantities of material, and do not place severe requirements on the spectroscopic properties of the binding partners. This review covers new developments in affinity capillary electrophoresis, electrospray ionization mass spectrometry (ESI-MS) and phasetransfer methods. PMID:19802330

  19. Use of experimental design and effective mobility calculations to develop a method for the determination of antimicrobials by capillary electrophoresis.

    PubMed

    Mamani, Mónica Cecília Vargas; Amaya-Farfan, Jaime; Reyes, Felix Guillermo Reyes; Silva, José Alberto Fracassi da; Rath, Susanne

    2008-09-15

    A capillary zone electrophoresis (CZE) method for the determination of chloramphenicol (CLP), danofloxacin (DANO), ciprofloxacin (CIPRO), enrofloxacin (ENRO), sulfamethazine (SMZ), sulfaquinoxaline (SQX) and sulfamethoxazole (SMX) is described. For the development, the effective mobilities were estimated and a central composite design was performed. The method was in-house validated for CLP, CIPRO, ENRO and SMX determination in pharmaceuticals. In comparison with the HPLC method recommended by the United States Pharmacopoeia, this CZE method exhibited the same performance, with the advantage that seven different antimicrobials in pharmaceutical formulations could be simultaneously determined. PMID:18761147

  20. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Y.

    1994-07-27

    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 {mu}M 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.

  1. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    PubMed

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results. PMID:26402948

  2. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    PubMed

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results.

  3. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    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.

  4. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

  5. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  6. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

  7. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  8. Nonlinear waves in capillary electrophoresis

    PubMed Central

    Ghosal, Sandip; Chen, Zhen

    2011-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments. PMID:20238181

  9. Determination of nitrate and nitrite in Hanford defense waste(HDW) by reverse polarity capillary zone electrophoresis (RPCE)method

    SciTech Connect

    Metcalf, S.G.

    1998-06-10

    This paper describes the first application of reverse polarity capillary zone electrophoresis (RPCE) for rapid and accurate determination of nitrate and nitrite in Hanford Defense Waste (HDW). The method development was carried out by using Synthetic Hanford Waste (SHW), followed by the analysis of 4 real HDW samples. Hexamethonium bromide (HMB) was used as electroosmotic flow modifier in borate buffer at pH 9.2 to decrease the electroosmotic flow (EOF) in order to enhance the speed of analysis and the resolution of nitrate and nitrite in high ionic strength HDW samples. The application of this capillary zone electrophoresis method, when compared with ion chromatography for two major components of HDW, nitrate and nitrite slightly reduced analysis time, eliminated most pre-analysis handling of the highly radioactive sample, and cut analysis wastes by more than 2 orders of magnitude. The analysis of real HDW samples that were validated by using sample spikes showed a concentration range of 1.03 to 1.42 M for both nitrate. The migration times of the real HDW and the spiked HDW samples were within a precision of less than 3% relative standard deviation. The selectivity ratio test used for peak confirmation of the spiked samples was within 96% of the real sample. Method reliability was tested by spiking the matrix with 72.4 mM nitrate and nitrite. Recoveries for these spiked samples were 93-103%.

  10. A microdestructive capillary electrophoresis method for the analysis of blue-pen-ink strokes on office paper.

    PubMed

    Calcerrada, Matías; González-Herráez, Miguel; Garcia-Ruiz, Carmen

    2015-06-26

    This manuscript describes the development of a capillary electrophoresis (CE) method for the detection of acid and basic dyes and its application to real samples, blue-pen-ink strokes on office paper. First, a capillary zone electrophoresis (CZE) method was developed for the separation of basic and acid dyes, by studying the separation medium (buffer nature, pH and relative amount of additive) and instrumental parameters (temperature, voltage and capillary dimensions). The method performance was evaluated in terms of selectivity, resolution (above 5 and 2 for acid dyes and basic dyes, respectively, except for two basic dye standards), LOD (lower than 0.4 mg/L) and precision as intraday and interday RSD values of peak migration times (lower than 0.6%). The developed method was then applied to 34 blue pens from different technologies (rollerball, ballpoint, markers) and with different ink composition (gel, water-based, oil-based). A microdestructive sample treatment using a scalpel to scratch 0.3mg of ink stroke was performed. The entire electropherogram profile allowed the visual discrimination between different types of ink and brands, being not necessary a statistical treatment. A 100% of discrimination was achieved between pen technologies, brands, and models, although non-reproducible zones in the electropherograms were found for blue gel pen samples. The two different batches of blue oil-based pens were also differentiated. Thus, this method provides a simple, microdestructive, and rapid analysis of different blue pen technologies which may complement the current analysis of questioned documents performed by forensic laboratories. PMID:26003620

  11. Microfabricated polymer chip for capillary gel electrophoresis.

    PubMed

    Hong, J W; Hosokawa, K; Fujii, T; Seki, M; Endo, I

    2001-01-01

    A polymer (PDMS: poly(dimethylsiloxane)) microchip for capillary gel electrophoresis that can separate different sizes of DNA molecules in a small experimental scale is presented. This microchip can be easily produced by a simple PDMS molding method against a microfabricated master without the use of elaborate bonding processes. This PDMS microchip could be used as a single use device unlike conventional microchips made of glass, quartz or silicon. The capillary channel on the chip was partially filled with agarose gel that can enhance separation resolution of different sizes of DNA molecules and can shorten the channel length required for the separation of the sample compared to capillary electrophoresis in free-flow or polymer solution format. We discuss the optimal conditions for the gel preparation that could be used in the microchannel. DNA molecules were successfully driven by an electric field and separated to form bands in the range of 100 bp to 1 kbp in a 2.0% agarose-filled microchannel with 8 mm of effective separation length.

  12. Method development for the enantiomeric purity determination of low concentrations of adrenaline in local anaesthetic solutions by capillary electrophoresis.

    PubMed

    Sänger-van de Griend, Cari E; Ek, Anders G; Widahl-Näsman, Monica E; Andersson, E K Margareta

    2006-04-11

    L-adrenaline is often included in local anaesthetic (LA) solutions for injection to improve the quality of the anaesthetic block. The concentration of the LA is between 2.5 and 20 mg/ml and the concentration of adrenaline is typically < or = 0.1% of the LA concentration. In order to follow the racemization into d-adrenaline, not only is chiral separation needed but also sufficient resolution from the LA and other components of the injection solution. Furthermore, very high sensitivity is needed in order to be able to determine the d-enantiomer at very low concentrations, i.e. down to about 0.1 microg/ml. The development of a chiral capillary electrophoresis method that is able to determine the racemization of adrenaline is described, together with a limited validation. Samples are injected without pretreatment and analysed with a capillary electrophoresis buffer containing 40 mM heptakis(2,6-di-O-methyl)-beta-cyclodextrin, 0.10 M phosphoric acid and 0.05 M triethanolamine. The amounts of d-adrenaline found in the LA products tested were typically < 3% of the l-adrenaline concentration and < 0.003% of the LA concentration.

  13. Capillary zone electrophoresis in pharmaceutical analysis.

    PubMed

    Fanali, S; Cristalli, M; Nardi, A; Ossicini, L; Shukla, S K

    1990-06-01

    The paper presents a brief characterization of capillary zone electrophoresis, a modern analytical separation method with high expediency for practical applications, especially in pharmaceutical analysis. Basic theoretical considerations are presented and discussed to explain the effects of the operational parameters upon the separation efficiency and resolution of species. Descriptions of simple instrumentation and of the analytical procedure itself are given. Experimental examples are given of the separation of mixtures of pharmaceutically important compounds and of the effects of operational parameters, especially pH of BGE and voltage applied. Lastly, the practical application of CZE for analysis of isoxsuprine in commercial preparations is shown.

  14. Analytical biotechnology: Capillary electrophoresis and chromatography

    SciTech Connect

    Horvath, C.; Nikelly, J.G.

    1990-01-01

    The papers describe the separation, characterization, and equipment required for the electrophoresis or chromatography of cyclic nucleotides, pharmaceuticals, therapeutic proteins, recombinant DNA products, pheromones, peptides, and other biological materials. One paper, On-column radioisotope detection for capillary electrophoresis, has been indexed separately for inclusion on the data base.

  15. Internal standard capillary electrophoresis as a high-throughput method for pKa determination in drug discovery and development.

    PubMed

    Cabot, Joan M; Fuguet, Elisabet; Rosés, Martí

    2014-10-13

    A novel high-throughput method for determining acidity constants (pKa) by capillary electrophoresis (CE) is developed. The method, based on the use of an internal standard (IS-CE), is implemented as a routine method for accurate experimental pKa determination of drugs undergoing physicochemical measurements in drug discovery laboratories. Just two electropherograms at 2 different pH values are needed to calculate an acidity constant. Several ISs can be used in the same buffer and run to enhance precision. With 3 ISs, for example, the pKa of the test compound (TC) can be obtained in triplicate in less than 3 min of electrophoresis. It has been demonstrated that the IS-CE method eliminates some systematic errors, maintaining, or even increasing the precision of the results compared with other methods. Furthermore, pH buffer instability during electrophoretic runs is not a problem in the IS-CE method. It is also proved that after 16 h of electroseparation using the same buffer vial, pH may change by around one unit; but the pKa calculated by the IS-CE method remains constant. Thus, IS-CE is a powerful high-throughput method for pKa determination in drug discovery and development.

  16. Fast high-throughput method for the determination of acidity constants by capillary electrophoresis: I. Monoprotic weak acids and bases.

    PubMed

    Fuguet, Elisabet; Ràfols, Clara; Bosch, Elisabeth; Rosés, Martí

    2009-04-24

    A new and fast method to determine acidity constants of monoprotic weak acids and bases by capillary zone electrophoresis based on the use of an internal standard (compound of similar nature and acidity constant as the analyte) has been developed. This method requires only two electrophoretic runs for the determination of an acidity constant: a first one at a pH where both analyte and internal standard are totally ionized, and a second one at another pH where both are partially ionized. Furthermore, the method is not pH dependent, so an accurate measure of the pH of the buffer solutions is not needed. The acidity constants of several phenols and amines have been measured using internal standards of known pK(a), obtaining a mean deviation of 0.05 pH units compared to the literature values. PMID:19168179

  17. Fast high-throughput method for the determination of acidity constants by capillary electrophoresis: I. Monoprotic weak acids and bases.

    PubMed

    Fuguet, Elisabet; Ràfols, Clara; Bosch, Elisabeth; Rosés, Martí

    2009-04-24

    A new and fast method to determine acidity constants of monoprotic weak acids and bases by capillary zone electrophoresis based on the use of an internal standard (compound of similar nature and acidity constant as the analyte) has been developed. This method requires only two electrophoretic runs for the determination of an acidity constant: a first one at a pH where both analyte and internal standard are totally ionized, and a second one at another pH where both are partially ionized. Furthermore, the method is not pH dependent, so an accurate measure of the pH of the buffer solutions is not needed. The acidity constants of several phenols and amines have been measured using internal standards of known pK(a), obtaining a mean deviation of 0.05 pH units compared to the literature values.

  18. Simultaneous determination of galanthamine and lycorine in Lycoris radiata by a capillary electrophoresis with an electrochemiluminescence method.

    PubMed

    Wang, Yanchao; Zhu, Guimei; Li, Xia; Hao, Zaibin

    2014-10-01

    A novel capillary electrophoresis with electrochemiluminescence determination method was developed for the determination of two alkaloids based on the electrochemiluminescence signal enhancement effect of the tertiary amine group on tris(2,2'-bipyridyl)ruthenium(II). A linear relationship between the electrochemiluminescence peak area and concentrations of galanthamine and lycorine in the range of 0.07 ∼ 17 μg/mL and 0.07 ∼ 18 μg/mL was obtained and the detection limit was 0.008 and 0.002 μg/mL, respectively. The method is selective, simple, and convenient. It had been successfully applied to the analysis of galanthamine and lycorine in Lycoris radiata samples purchased from a local market. PMID:25082559

  19. Determination of somatropin charged variants by capillary zone electrophoresis - optimisation, verification and implementation of the European pharmacopoeia method.

    PubMed

    Storms, S M; Feltus, A; Barker, A R; Joly, M-A; Girard, M

    2009-03-01

    Measurement of somatropin charged variants by isoelectric focusing was replaced with capillary zone electrophoresis in the January 2006 European Pharmacopoeia Supplement 5.3, based on results from an interlaboratory collaborative study. Due to incompatibilities and method-robustness issues encountered prior to verification, a number of method parameters required optimisation. As the use of a diode array detector at 195 nm or 200 nm led to a loss of resolution, a variable wavelength detector using a 200 nm filter was employed. Improved injection repeatability was obtained by increasing the injection time and pressure, and changing the sample diluent from water to running buffer. Finally, definition of capillary pre-treatment and rinse procedures resulted in more consistent separations over time. Method verification data are presented demonstrating linearity, specificity, repeatability, intermediate precision, limit of quantitation, sample stability, solution stability, and robustness. Based on these experiments, several modifications to the current method have been recommended and incorporated into the European Pharmacopoeia to help improve method performance across laboratories globally.

  20. An on-line stacking capillary electrophoresis method for the analysis of Δ(9)-tetrahydrocannabinol and its metabolites.

    PubMed

    Cheng, Hui-Ling; Tsai, Yi-Hsuan; Hsu, Wan-Ling; Lin, Yi-Hui

    2015-12-24

    The objective of this study was to establish a practical and reliable analytical method for monitoring trace amounts of Δ(9)-tetrahydrocannabinol (THC) and its metabolites in biological samples. A novel on-line preconcentration capillary electrophoresis method combining large volume sample injection, anion selective exhaustive injection and sweeping was developed to enhance analytical sensitivity. A background buffer composed with 30mM phosphate buffer (pH 2.5) containing 40% methanol and 100mM SDS was used to suppress the electroosmotic flow of the uncoated fused silica capillary (40cm×50μm i.d.). High conductivity buffer (200mM phosphate, pH 2.5) was injected for analyte accumulation. The samples, prepared in phosphate buffer or Tris buffer, were introduced by hydrodynamic injection and electrokinetic injection. After sweeping, the separation was performed in micellar electrokinetic chromatography (MEKC) mode at -15kV. During the method validation, the coefficient of determination of the regression curve was measured at greater than 0.993, and the relative standard deviation and relative error were lower than 11.06% and 9.24%, respectively. Under optimized conditions, an improvement of up to 2000-fold higher sensitivity was achieved. This method was applied to the analysis of urine samples, indicating that it could be satisfactorily utilized in the toxicological and clinical monitoring of cannabis. PMID:26643722

  1. Application of a capillary electrophoresis method for simultaneous determination of preservatives in pharmaceutical formulations.

    PubMed

    Jaworska, Małgorzata; Szulińska, Zofia; Wilk, Małgorzata

    2005-02-01

    Preservatives are used to protect pharmaceutical formulations from microbial attack during the period of administration to the patient. Because of their biological activity, preservatives have to be identified and assayed according to the same rules as apply to active components. A number of methods for separation of preservatives are reported, to account for the heterogeneity of their chemical structures. A capillary electrophoretic method was devised for simple and simultaneous qualification and quantification of the preservatives most often included in pharmaceuticals, such as benzyl alcohol, parabens, phenol, m-cresol, chlorobutanol, thimerosal. After systematic method development, the electrophoretic conditions were defined as: 50 mM borate buffer pH 9.0 containing 20 mM SDS. Separations were performed at a temperature of 20 degrees C and with detection at 214 nm. Preservatives under examination can be analyzed within a 10 min run. The method was successfully validated and applied to the determination of preservatives in a number of pharmaceuticals. Results from the CE method were compared with those from reference methods.

  2. Using capillary electrophoresis to characterize polymeric particles.

    PubMed

    Riley, Kathryn R; Liu, Sophia; Yu, Guo; Libby, Kara; Cubicciotti, Roger; Colyer, Christa L

    2016-09-01

    Capillary electrophoresis (CE) was used for the characterization of a variety of polymeric micron and sub-micron particles based on size, surface functionality, and binding properties. First, a robust capillary zone electrophoresis (CZE) method was developed for the baseline separation and quantitation of commercially available polystyrene particles with various surface modifications (including amino, carboxylate, and sulfate functional groups) and various sizes (0.2, 0.5, 1.0, and 3.0μm). The separation of DNA-templated polyacrylamide particles from untemplated particles (as used for the Ion Torrent Personal Genome Machine) was demonstrated. Finally, using the 29-base thrombin aptamer and thrombin protein as a model system, a study was undertaken to determine dissociation constants for the aptamer and protein in free solution and when the aptamer was conjugated to a particle, with the goal of better understanding how the use of solid substrates, like particles, affects selection and binding processes. Dissociation constants were determined and were found to be approximately 5-fold higher for the aptamer conjugated to a particle relative to that in free solution. PMID:27543386

  3. Development of a capillary electrophoresis method for analyzing adenosine deaminase and purine nucleoside phosphorylase and its application in inhibitor screening.

    PubMed

    Qi, Yanfei; Li, Youxin; Bao, James J

    2016-08-01

    A novel capillary electrophoresis (CE) method was developed for simultaneous analysis of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) in red blood cells (RBCs). The developed method considered and took advantage of the natural conversion from the ADA product, inosine to hypoxanthine. The transformation ratio was introduced for ADA and PNP analysis to obtain more reliable results. After optimizing the enzymatic incubation and electrophoresis separation conditions, the determined activities of ADA and PNP in 12 human RBCs were 0.237-0.833 U/ml and 9.013-10.453 U/ml packed cells, respectively. The analysis of ADA in mice RBCs indicated that there was an apparent activity difference between healthy and hepatoma mice. In addition, the proposed method was also successfully applied in the inhibitor screening from nine traditional Chinese medicines, and data showed that ADA activities were strongly inhibited by Rhizoma Chuanxiong and Angelica sinensis. The inhibition effect of Angelica sinensis on ADA is first reported here and could also inhibit PNP activity. PMID:27173606

  4. Development and validation of a capillary electrophoresis method for the enantiomeric purity determination of RS86017 using experimental design.

    PubMed

    Liu, Meixia; Zheng, Yan; Ji, Yibing; Zhang, Can

    2011-04-28

    A selective capillary electrophoresis method for determination of enantiomeric purity of RS86017, a new antiarrhythmic agent with two chiral centers, was developed and validated using sulfobutyl ether-β-cyclodextrin as chiral selector. The concentration of the chiral selector and organic modifier, pH of background electrolyte (BGE), capillary temperature, and applied voltage were systematically optimized by using orthogonal design and concentration of chiral selector was further optimized. The optimal conditions included 25mM phosphate buffer at pH 8.0, containing 28mg/mL sulfobutyl ether-β-cyclodextrin and 20% acetonitrile as running buffer, an applied voltage of 22kV, and a temperature of 20°C. The detection wavelength was 206nm. The obtained method was capable of separating RS86017 from its potential chiral impurities, the S,R-enantiomer, the R,R-diastereomer and the S,S-diastereomer with a short analysis time of 10min. The separation was validated with respect to its selectivity, repeatability, linearity, precision, accuracy, limits of detection (LOD), limits of quantitation (LOQ) and robustness testing. The LODs and LOQs were 0.8μg/mL and 2.5μg/mL for all isomers of RS86017, respectively. Finally, the method was used to investigate the chiral purity of RS86017 in bulk samples.

  5. High-performance capillary electrophoresis of histones

    SciTech Connect

    Gurley, L.R.; London, J.E.; Valdez, J.G.

    1991-01-01

    A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

  6. Separation of Recombinant Therapeutic Proteins Using Capillary Gel Electrophoresis and Capillary Isoelectric Focusing.

    PubMed

    De Jong, Caitlyn A G; Risley, Jessica; Lee, Alexis K; Zhao, Shuai Sherry; Chen, David D Y

    2016-01-01

    Detailed step-by-step methods for protein separation techniques based on capillary electrophoresis (CE) are described in this chapter. Focus is placed on two techniques, capillary gel electrophoresis (CGE) and capillary isoelectric focusing (cIEF). CGE is essentially gel electrophoresis, performed in a capillary, where a hydrogel is used as a sieving matrix to separate proteins or peptides based on size. cIEF separates proteins or peptides based on their isoelectric point (pI), the pH at which the protein or peptide bears no charges. Detailed protocols and steps (including capillary preparation, sample preparation, CE separation conditions, and detection) for both CGE and cIEF presented so that readers can follow the described methods in their own labs. PMID:27473487

  7. Capillary electrophoresis for drug analysis in body fluids.

    PubMed

    Thormann, W; Zhang, C X; Schmutz, A

    1996-08-01

    Capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) represent attractive methods for the determination of drugs and metabolites in body fluids. In CZE, minute (nanoliter) quantities of samples are applied to the beginning of a fused-silica capillary filled with buffer. On application of a high-voltage DC field, charged solutes begin to separate and are swept through the capillary by the combined action of electrophoresis and electroosmotic bulk flow and are on-column detected toward the capillary end. In MECC, the buffer contains charged micelles (e.g., dodecyl sulfate micelles) and both uncharged and charged solutes separate based on differential partitioning between the micelles and the surrounding buffer and, if charged, also by differential charge effects, including electrophoresis. Based on validated MECC drug assays developed in our laboratory, key aspects of measuring drug levels by MECC, including sample preparation, solute detection and identification, quantitation, reproducibility, and quality assurance are discussed. Drug levels determined by MECC are shown to be in good agreement with those obtained by nonisotopic immunoassays and/or high-performance liquid chromatography (HPLC). Using on-column multi-wavelength detection, this technology is also well suited for toxicological drug screening and confirmation and for the exploration of drug metabolism. Compared with HPLC and gas chromatography, capillary electrophoresis has distinct advantages, including automation, small sample size, minimal sample preparation, use of very small amounts of organic solvents and inexpensive chemicals, ease of buffer change and method development, and low cost of capillary columns. Electrokinetic capillary assays are complementary to the widely employed immunoassays. The state of the art and the pros and cons of capillary electrophoresis for the determination of drugs in body fluids are discussed with the goal of encouraging

  8. Determination of enantiomeric excess by capillary electrophoresis.

    PubMed

    Blomberg, L G; Wan, H

    2000-06-01

    Capillary electrophoresis (CE) is becoming an established method for the determination of chiral trace impurities. This paper provides an overview of the state of the art of CE for such determinations. Detection limits of 0.1% impurity is widely accepted as a minimum requirement for chiral trace impurity determinations. This can be relatively easily achieved with CE. However, determination of lower concentrations requires careful optimization of the separation system. Four factors that are of particular significance for trace enantiomeric determinations: resolution, limit of detection, linear range and type of detection, are discussed. Further, the advantages and disadvantages of derivatization in this context are treated as well as the separation approach, ie., direct chiral separation or separation after the formation of diastereomers. It is concluded that the limit of impurity detection can be about 0.05% when UV detection is employed. Using laser-induced fluorescence detection, a quantitative determination at the 0.005% level is often possible.

  9. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

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

    1997-12-09

    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.

  10. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.

    1997-12-09

    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.

  11. In-vial liquid-liquid microextraction-capillary electrophoresis method for the determination of phenolic acids in vegetable oils.

    PubMed

    Abu Bakar, Nur Bahiyah; Makahleh, Ahmad; Saad, Bahruddin

    2012-09-12

    An in-vial liquid-liquid microextraction method was developed for the selective extraction of the phenolic acids (caffeic, gallic, cinnamic, ferulic, chlorogenic, syringic, vanillic, benzoic, p-hydroxybenzoic, 2,4-dihydroxybenzoic, o-coumaric, m-coumaric and p-coumaric) in vegetable oil samples. The optimised extraction conditions for 20 g sample were: volume of diluent (n-hexane), 2 mL; extractant, methanol: 5 mM sodium hydroxide (60:40; v/v); volume of extractant, 300 μL (twice); vortex, 1 min; centrifugation, 5 min. Recoveries for the studied phenolic acids were 80.1-119.5%. The simultaneous determination of the phenolic acid extracts was investigated by capillary electrophoresis (CE). Separations were carried out on a bare fused-silica capillary (50 μm i.d.× 40 cm length) involving 25 mM sodium tetraborate (pH 9.15) and 5% methanol as CE background electrolyte in the normal polarity mode, voltage of 30 kV, temperature of 25°C, injection time of 4s (50 mbar) and electropherograms were recorded at 200 nm. The phenolic acids were successfully separated in less than 10 min. The validated in-vial LLME-CE method was applied to the determination of phenolic acids in vegetable oil samples (extra virgin olive oil, virgin olive oil, pure olive oil, walnut oil and grapeseed oil). The developed method shows significant advantages over the current methods as lengthy evaporation step is not required. PMID:22884208

  12. Analysis of inorganic species in environmental samples by capillary electrophoresis.

    PubMed

    Valsecchi, S M; Polesello, S

    1999-02-26

    The use of capillary electrophoresis for the determination of inorganic species in environmental samples is reviewed. Topics covered include the separation of inorganic anions, inorganic cations, transition metal cations and organometals in different environmental matrices, such as atmospheric deposition, atmospheric aerosols, gases, natural waters, waste waters, soil, sediment and marine biological samples. Cited literature is gathered according to the type of matrix, so that the focus is on the discussion of matrix effects rather than on the method development for a single class of compounds. For each matrix, surveyed methods are tabulated in order to assist the method selection. Innovative applications of capillary electrophoresis to advanced environmental research are also emphasised.

  13. Determination of fumaric and maleic acids with stacking analytes by transient moving chemical reaction boundary method in capillary electrophoresis.

    PubMed

    He, Jian-Feng; Yang, Wei-Ying; Yao, Fu-Jun; Zhao, Hong; Li, Xiang-Jun; Yuan, Zhuo-Bin

    2011-06-17

    The paper presents an on-line transient moving chemical reaction boundary (MCRB) method for simply but efficiently stacking analytes in capillary electrophoresis (CE). The CE technique was developed for a rapid determination of fumaric and maleic acid. Based on the theory of MCRB, Effects of several important factors such as the pH and concentration of running buffer and the conditions of stacking analytes were investigated to acquire the optimum conditions. The optimized separations were carried out in a 20 mmol/L sulphate neutralized with ethylenediamine to pH 6.0 electrolytes using a capillary coated with poly (diallyldimethylammonium chloride) and direct UV detection at 214 nm. The optimized preconcentrations were carried out in 50 mmol/L borax (pH 9.0). The calibration curves were linear in the concentration range of 1.0×10⁻⁷-1.0×10⁻⁴ mol/L and 5.0×10⁻⁷-1.0×10⁻⁴ mol/L for fumaric and maleic acid with correlation coefficients higher than 0.9991. The detection limits were 5.34×10⁻⁸ mol/L for fumaric acid and 1.92×10⁻⁷ mol/L for maleic acid. This method was applied for determination of fumaric acid in apple juice and of fumaric and maleic acid in dl-malic, the recovery tests established for real samples were within the range 95-105%. This work provided a valid and simple approach to detect fumaric and maleic acid.

  14. Analysis of protein therapeutics by capillary electrophoresis: applications and challenges.

    PubMed

    Ma, S

    2005-01-01

    Capillary electrophoresis (CE) has been increasingly used for the analysis of recombinant protein therapeutics in the biotechnology industry over the past several years. In this paper, an overview of the major applications implemented at Genentech Inc. is presented. The applications highlighted in this article are divided into the following three general areas: (i) CE as a replacement for slab gel electrophoresis, particularly capillary electrophoresis-sodium dodecylsulphate and capillary isoelectric focusing; (ii) CE to monitor protein charge heterogeneity as an orthogonal technique to the traditional on-exchange chromatographic methods; and (iii) CE for carbohydrate analysis, including both oligosaccharide and monosaccharide analysis. Overall, the advantages of these CE-based methodologies include automation, ease of quantification, rapid analysis time, enhanced resolution, and robustness when compared to the traditional methods. There are, however, still some challenges in applying CE for protein analysis, particularly in the area of characterization due to the miniaturization nature of CE.

  15. Development and validation of a capillary electrophoresis method for the determination of codeine, diphenhydramine, ephedrine and noscapine in pharmaceuticals.

    PubMed

    Gomez, María R; Sombra, Lorena; Olsina, Roberto A; Martínez, Luis D; Silva, María F

    2005-01-01

    The present work describes a simple, accurate and rapid method for the separation and simultaneous determination of codeine, diphenhydramine, ephedrine and noscapine present in cough-cold syrup formulations by capillary zone electrophoresis. Factors affecting the separation were the buffer pH and concentration, applied voltage, and presence of additives. Separations were carried out in less than 10 min with a 20 mM sodium tetraborate buffer, pH 8.50. The carrier electrolyte gave baseline separation with good resolution, great reproducibility and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, the lower limits of detection being within the range 0.42-1.33 microg ml(-1). Detection was performed by UV absorbance at wavelengths of 205 and 250 nm. Quantification of the components in actual syrup formulations was calculated against the responses of freshly prepared external standard solutions. The method was validated and met all analysis requirements of quality assurance and quality control. The procedure was fast and reliable and commercial pharmaceuticals could be analyzed without prior sample clean-up procedure.

  16. A method for high-throughput, sensitive analysis of IgG Fc and Fab glycosylation by capillary electrophoresis

    PubMed Central

    Mahan, Alison E; Tedesco, Jacquelynne; Dionne, Kendall; Baruah, Kavitha; Cheng, Hao D.; De Jager, Philip L.; Barouch, Dan H.; Suscovich, Todd; Ackerman, Margaret; Cripsin, Max; Alter, Galit

    2016-01-01

    The N-glycan of the IgG constant region (Fc) plays a central role in tuning and directing multiple antibody functions in vivo, including antibody-dependent cellular cytotoxicity, complement deposition, and the regulation of inflammation, among others. However, traditional methods of N-glycan analysis, including HPLC and mass spectrometry, are technically challenging and ill suited to handle the large numbers of low concentration samples analyzed in clinical or animal studies of the N-glycosylation of polyclonal IgG. Here we describe a capillary electrophoresis-based technique to analyze plasma-derived polyclonal IgG-glycosylation quickly and accurately in a cost-effective, sensitive manner that is well suited for high-throughput analyses. Additionally, because a significant fraction of polyclonal IgG is glycosylated on both Fc and Fab domains, we developed an approach to separate and analyze domain-specific glycosylation in polyclonal human, rhesus and mouse IgGs. Overall, this protocol allows for the rapid, accurate, and sensitive analysis of Fc-specific IgG glycosylation, which is critical for population-level studies of how antibody glycosylation may vary in response to vaccination or infection, and across disease states ranging from autoimmunity to cancer in both clinical and animal studies. PMID:25523925

  17. An optimized capillary electrophoresis method for the simultaneous analysis of biomass degradation products in ionic liquid containing samples.

    PubMed

    Aid, Tiina; Paist, Loore; Lopp, Margus; Kaljurand, Mihkel; Vaher, Merike

    2016-05-20

    An indirect capillary electrophoresis method for a quantitative determination of mono-, di- and oligosaccharides was developed to investigate biomass degradation, the isomerization of glucose into fructose and conversion of fructose to 5-hydroxymethylfurfural (5-HMF) in ionic liquids (ILs). Three chromophores, namely 2,6-pyridinedicarboxylic acid (PDC), maleic acid and phthalic acid, were used to perform indirect detection. The electroosmotic flow (EOF) was reversed to reduce analysis time, using 1-tetradecyl-3-methylimidazolium chloride (C14MImCl). The simultaneous separation of the underivatized mono-, di- and oligosaccharides was performed using four cellodextrin oligomers (cellotriose, cellotetraose, cellopentaose, cellohexaose), eight carbohydrates (xylose, fructose, glucose, galactose, lactose, cellobiose, raffinose, sucrose), two organic acids (acetic acid, levulinic acid) and 5-HMF. The best performance was obtained using background electrolyte (BGE) composed of 138.2mM NaOH, 40mM maleic acid and 5mMC14MImCl, the applied voltage was -21.7kV. The linear ranges for analyzed compounds were following: organic acids, raffinose and sucrose from 0.20 to 7mM, cellodextrin oligomers from 0.25 to 5mM, other analyzed carbohydrates from 0.25 to 7mM and 5-HMF from 0.05 to 7mM. The relative standard deviations (RSD) of peak areas varied from 3.47 to 9.62% during a 5-day analysis period and 0.58-5.29% during one day. PMID:27095128

  18. Micro-injector for capillary electrophoresis.

    PubMed

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

    2015-08-01

    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.

  19. Optimization and validation of a rapid method to determine citrate and inorganic phosphate in milk by capillary electrophoresis.

    PubMed

    Izco, J M; Tormo, M; Harris, A; Tong, P S; Jimenez-Flores, R

    2003-01-01

    Quantification of phosphate and citrate compounds is very important because their distribution between soluble and colloidal phases of milk and their interactions with milk proteins influence the stability and some functional properties of dairy products. The aim of this work was to optimize and validate a capillary electrophoresis method for the rapid determination of these compounds in milk. Various parameters affecting analysis have been optimized, including type, composition, and pH of the electrolyte, and sample extraction. Ethanol, acetonitrile, sulfuric acid, water at 50 degrees C or at room temperature were tested as sample buffers (SB). Water at room temperature yielded the best overall results and was chosen for further validation. The extraction time was checked and could be shortened to less than 1 min. Also, sample preparation was simplified to pipet 12 microl of milk into 1 ml of water containing 20 ppm of tartaric acid as an internal standard. The linearity of the method was excellent (R2 > 0.999) with CV values of response factors <3%. The detection limits for phosphate and citrate were 5.1 and 2.4 nM, respectively. The accuracy of the method was calculated for each compound (103.2 and 100.3%). In addition, citrate and phosphate content of several commercial milk samples were analyzed by this method, and the results deviated less than 5% from values obtained when analyzing the samples by official methods. To study the versatility of the technique, other dairy productssuch as cream cheese, yogurt, or Cheddar cheese were analyzed and accuracy was similar to milk in all products tested. The procedure is rapid and offers a very fast and simple sample preparation. Once the sample has arrived at the laboratory, less than 5 min (including handling, preparation, running, integration, and quantification) are necessary to determine the concentration of citric acid and inorganic phosphate. Because of the speed and accuracy of this method, it is promising as an

  20. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Ghosal, Sandip

    2006-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care, and forensics. In capillary electrophoresis (which has evolved from its predecessor, slab-gel electrophoresis), the sample migrates through a single microcapillary instead of through the network of pores in a gel. A fundamental design problem is to minimize dispersion in the separation direction. Molecular diffusion is inevitable and sets a theoretical limit on the best separation that can be achieved. But in practice, there are a number of effects arising out of the interplay between fluid flow, chemistry, thermal effects, and electric fields that result in enhanced dispersion. This paper reviews the subject of fluid flow in such capillary microchannels and examines the various causes of enhanced dispersion that limit the efficiency of separation.

  1. Metal Ions Analysis with Capillary Zone Electrophoresis.

    PubMed

    Malik, Ashok Kumar; Aulakh, Jatinder Singh; Kaur, Varinder

    2016-01-01

    Capillary electrophoresis has recently attracted considerable attention as a promising analytical technique for metal ion separations. Significant advances that open new application areas for capillary electrophoresis in the analysis of metal species occurred based on various auxiliary separation principles. These are mainly due to complexation, ion pairing, solvation, and micellization interactions between metal analytes and electrolyte additives, which alter the separation selectivity in a broad range. Likewise, many separation studies for metal ions have been concentrated on the use of preelectrophoresis derivatization methodology. Approaches suitable for manipulation of selectivity for different metal species including metal cations, metal complexes, metal oxoanions, and organometallic compounds, are discussed, with special attention paid to the related electrophoretic system variables using illustrative examples. PMID:27645740

  2. Capillary Electrophoresis in Food and Foodomics.

    PubMed

    Ibáñez, Clara; Acunha, Tanize; Valdés, Alberto; García-Cañas, Virginia; Cifuentes, Alejandro; Simó, Carolina

    2016-01-01

    Quality and safety assessment as well as the evaluation of other nutritional and functional properties of foods imply the use of robust, efficient, sensitive, and cost-effective analytical methodologies. Among analytical technologies used in the fields of food analysis and foodomics, capillary electrophoresis (CE) has generated great interest for the analyses of a large number of compounds due to its high separation efficiency, extremely small sample and reagent requirements, and rapid analysis. The introductory section of this chapter provides an overview of the recent applications of capillary electrophoresis (CE) in food analysis and foodomics. Relevant reviews and research articles on these topics are tabulated including papers published in the period 2011-2014. In addition, to illustrate the great capabilities of CE in foodomics the chapter describes the main experimental points to be taken into consideration for a metabolomic study of the antiproliferative effect of carnosic acid (a natural diterpene found in rosemary) against HT-29 human colon cancer cells. PMID:27645749

  3. Rapid detection of bacteria in urine samples by the "three-plug-injection" method using capillary electrophoresis.

    PubMed

    Song, Lin; Li, Wanchen; Li, Guoxia; Wei, Dianjun; Ge, Peng; Li, Guizhen; Zheng, Fang; Sun, Xuguo

    2013-09-15

    This study explored a method that can rapidly detect bacteria in urine samples for the auxiliary determination of urinary tract infections (UTIs). Urine samples from patients with UTIs (230 cases) were obtained using aseptic technique. The urine biochemical assay was then carried out using an automated urine analyzer for all the urine samples. Bacterial species were identified by a combination of bacterial culture technique, morphological observation and the BACT-IST microbial identification/susceptibility analysis system. The most common seven species of bacteria in the study included Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter cloacae, Enterococcus faecalis, Staphylococcus aureus and Staphylococcus epidermidis. Bacterial samples were suspended in sample buffer solutions and separated by the "three-plug-injection" method using capillary electrophoresis (CE). Each species of bacteria appeared as a bacterial peak. The mixture of the seven species also provided only one peak. Further analysis showed that the concentration limit for the "three-plug-injection" method is 10(6) colony forming units (CFU)/mL, and there is a good linear relationship between the peak height and bacterial concentration (R(2)=0.99). The effect of urine composition on CE results was also investigated. The results showed that urine composition, i.e., proteins, white blood cells (WBCs) and red blood cells (RBCs), affected the peak retention time but could not affect the separation of bacteria. The results demonstrated that the bacteria in urine samples can be detected within 10min by the "three-plug-injection" method using CE. The "three-plug-injection" method is therefore suitable for the rapid detection of organisms in clinical urine samples from UTIs.

  4. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D'Silva, Arthur

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

  5. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D`Silva, A.

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

  6. [2012 annual review of capillary electrophoresis technology].

    PubMed

    Qu, Feng; Zhao, Xinying; Wang, Yong

    2012-12-01

    This paper reviews the capillary electrophoresis (CE) in 2012. Four international and three national conferences are included and the important reports are introduced briefly. Literatures searched from ISI Web of Science ranged in 2012.1.1 - 2012.12.1 are classified and introduced based on the biology and medicine applications as well as the use of detectors and the important analytical chemical journals.

  7. A sensitive non-aqueous capillary electrophoresis-mass spectrometric method for multiresidue analyses of beta-agonists in pork.

    PubMed

    Anurukvorakun, Oraphan; Buchberger, Wolfgang; Himmelsbach, Markus; Klampel, Christian W; Suntornsuk, Leena

    2010-06-01

    Non-aqueous capillary electrophoresis-mass spectrometry (NACE-MS) was developed for trace analyses of beta-agonists (i.e. clenbuterol, salbutamol and terbutaline) in pork. The NACE was in 18 mM ammonium acetate in methanol-acetonitrile-glacial acetic acid (66 : 33 : 1, v/v/v) using a voltage of 28 kV. The hyphenation of CE with a time-of-flight MS was performed by electrospray ionization interface employing 5 mM ammonium acetate in methanol-water (80 : 20, v/v) as the sheath liquid at a flow rate of 2 microL/min. Method sensitivity was enhanced by a co-injection technique (combination of hydrodynamic and electrokinetic injection) using a pressure of 50 mbar and a voltage of 10 kV for 12 s. The method was validated in comparison with HPLC-MS-MS. The NACE-MS procedure provided excellent detection limits of 0.3 ppb for all analytes. Method linearity was good (r(2) > 0.999, in a range of 0.8-1000 ppb for all analytes). Precision showed %RSDs of <17.7%. Sample pre-treatment was carried out by solid-phase extraction using mixed mode reversed phase/cation exchange cartridges yielding recoveries between 69 and 80%. The NACE-MS could be successfully used for the analysis of beta-agonists in pork samples and results showed no statistical differences from the values reported by the Ministry of Public Health, Thailand using HPLC-MS-MS method.

  8. Application of capillary electrophoresis in agricultural and soil chemistry research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a modern analytical technique, capillary electrophoresis (CE) has become an attractive method for characterizing molecules wit high structural complexity and a wide range of molecular weights. CE can be used to analyze many natural chemical components such as acids, biogenic amines, peptides, pro...

  9. Recent advances in amino acid analysis by capillary electrophoresis.

    PubMed

    Prata, C; Bonnafous, P; Fraysse, N; Treilhou, M; Poinsot, V; Couderc, F

    2001-11-01

    Amino acids are studied extensively using capillary electrophoresis. In this review we will report the different researchs which have been done in the literature since 1998. We will describe the developments of, detection methods, separations of enantiomers, the new medical applications, and amino acids in food and plants.

  10. Development of a capillary electrophoresis method for the characterization of "palo azul" (Eysenhardtia polystachya).

    PubMed

    Salinas-Hernández, Pastora; López-Bermúdez, Francisco J; Rodríguez-Barrientos, Damaris; Ramírez-Silva, María Teresa; Romero-Romo, Mario A; Morales-Anzures, Fernando; Rojas-Hernández, Alberto

    2008-03-01

    The tree Eysenhardtia polystachya (Ortega) Sarg. has quite a wide popular use within the traditional Mexican medicine as herbal remedy. Popular practices constitute a relevant enough basis to design optimum analytical methods in order to determine basic principles of diverse medicinal plants. This has become one of the essentials needed to characterize such products, for which it is fundamentally important to develop an efficient and reliable separation method. This work presents the results concerning the development and optimization of a novel CE method for the separation of components from water/etanol (1:1) extracts of E. polystachya, using the following conditions, considered the best obtained: phosphate buffer 10 mM, 20 kV voltage, and pH 8.1 at 214 nm and 50 mM, 12.5 kV voltage with pH 8.1 at 426 nm. The optimization takes into account the parameters associated in the resulting electropherograms, such as number of peaks, migration times, and the Deltat(m) of the neighboring peaks. Under optimal conditions the separation intended was attained within 15 and 20 min for 214 and 426 nm, respectively. The characterization method developed was applied to the analysis of diverse extracts of E. polystachya.

  11. Capillary electrophoresis coupled to biosensor detection.

    PubMed

    Bossi, A; Piletsky, S A; Righetti, P G; Turner, A P

    2000-09-15

    The present review highlights some modern aspects of biosensor revelation, a detection method which has already found a large number of applications in healthcare, food industry and environmental analysis. First, the concept of bio-recognition, which is at the heart of biosensor technology, is discussed, with emphasis on host-guest-like recognition mechanisms. This detection device has been successfully coupled, in its first applications, to chromatographic columns, which allow a high resolution of complex mixtures of analytes prior to interaction with the biosensing unit. The properties of the transducing elements, which should generate a signal (e.g., electrochemical, thermal, acoustic, optical) of proper intensity and of relative fast rise, are additionally evaluated and discussed. The review then focuses on potential applications of biosensing units in capillary electrophoresis (CE) devices. CE appears to be an excellent separation methodology to be coupled to biosensor detection, since it is based on miniaturized electrophoretic chambers, fast analysis times, complete automation in sample handling and data treatment and requires extremely small sample volumes. Although only a few applications of CE-based biosensors have been described up to the present, it is anticipated that this hyphenated technique could have a considerable expansion in the coming years.

  12. A capillary electrophoresis method to explore the self-assembly of a novel polypeptide ligand with quantum dots.

    PubMed

    Wang, Jianhao; Zhang, Chencheng; Liu, Li; Kalesh, Karunakaran A; Qiu, Lin; Ding, Shumin; Fu, Minli; Gao, Li-Qian; Jiang, Pengju

    2016-08-01

    Polyhistidine peptides are effective ligands to coat quantum dots (QDs). It is known that both the number of histidine (His) residues repeats and their structural arrangements in a peptide ligand play important roles in the assembly of the peptide onto CdSe/ZnS QDs. However, due to steric hindrance, a peptide sequence with more than six His residue tandem repeats would hardly coordinate well with Zn(2+) in the QD shell to further enhance the binding affinity. To solve this problem, a His-containing peptide ligand, ATTO 590-E2 G (NH)6 (ATTO-NH), was specifically designed and synthesized for assembly with QDs. With sequential injection of QDs and ATTO-NH into the capillary electrophoresis with fluorescence detection, strong Förster resonance energy transfer phenomenon between the QDs and the ATTO 590 dye was observed, indicating efficient self-assembly of the novel peptide onto the QDs to form ATTO-NH capped QDs inside the capillary. The binding stability of the ligand onto the QD was then systematically investigated by titrating with imidazole, His, and a his-tag containing competitive peptide. It is believed that this new in-capillary assay significantly reduced the sample consumption and the analysis time. By functionalizing QDs with certain metal cation-specific group fused peptide ligand, the QD-based probes could be even extended to the online detection of metal cations for monitoring environment in the future. PMID:27334251

  13. Separation of Peptides by Capillary Electrophoresis.

    PubMed

    Scriba, Gerhard K E

    2016-01-01

    Peptides are an important class of analytes in chemistry, biochemistry, food chemistry, as well as medical and pharmaceutical sciences including biomarker analysis in peptidomics and proteomics. As a high-resolution technique, capillary electrophoresis (CE) is well suited for the analysis of polar compounds such as peptides. In addition, CE is orthogonal to high-performance liquid chromatography (HPLC) as both techniques are based on different physicochemical separation principles. For the successful development of peptide separations by CE, operational parameters including puffer pH, buffer concentration and buffer type, applied voltage, capillary dimensions, as well as background electrolyte additives such as detergents, ion-pairing reagents, cyclodextrins, (poly)amines, and soluble polymers have to be considered and optimized. PMID:27645745

  14. Using capillary electrophoresis for failure analysis

    SciTech Connect

    Kelly, R.G.; Scully, H.S.; Stoner, G.E. . Center for Electrochemical Science and Engineering)

    1993-07-01

    Capillary electrophoresis (CE), an advanced solution analysis technique, can be used for failure analysis of corroded components. It has high sensitivity (concentrations as low as parts-per-trillion) and can detect quantitatively a large number of ionic species. CE determined the vapor-phase attack by organic acids, mainly acetic acid, on an electrical equipment enclosure. These acids most likely originated from the seasoning of the oak pallets used to transport the manufactured items, accumulating inside the shrink-wrap film used to bind packages to the pallet.

  15. Integrated chip-based capillary electrophoresis.

    PubMed

    Effenhauser, C S; Bruin, G J; Paulus, A

    1997-11-01

    Integrated capillary electrophoresis (ICE) is emerging as a new analytical tool allowing fast, automated, miniaturized and multiplexed assays, thus meeting the needs of the pharmaceutical industry in drug development. The current state-of-the-art of ICE is described with an emphasis on the choice of the support material (glass or polymeric materials), electrokinetic fluid handling, and injection and detection issues. Strategies and chip designs for pre- or post-column derivatization, DNA sequencing, on-line PCR analysis, on-chip enzymatic sample digestion, fraction isolation, and immunoassays are presented. The review concludes with a brief outlook.

  16. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect

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

    2014-06-17

    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.

  17. Pressure-assisted electrokinetic injection for on-line enrichment in capillary electrophoresis-mass spectrometry: a sensitive method for measurement of ten haloacetic acids in drinking water.

    PubMed

    Zhang, Huijuan; Zhu, Jiping; Aranda-Rodriguez, Rocio; Feng, Yong-Lai

    2011-11-01

    Haloacetic acids (HAAs) are by-products of the chlorination of drinking water containing natural organic matter and bromide. A simple and sensitive method has been developed for determination of ten HAAs in drinking water. The pressure-assisted electrokinetic injection (PAEKI), an on-line enrichment technique, was employed to introduce the sample into a capillary electrophoresis (CE)-electrospray ionization-tandem mass spectrometry system (ESI-MS/MS). HAAs were monitored in selected reaction monitoring mode. With 3 min of PAEKI time, the ten major HAAs (HAA10) in drinking water were enriched up to 20,000-fold into the capillary without compromising resolution. A simple solid phase clean-up method has been developed to eliminate the influence of ionic matrices from drinking water on PAEKI. Under conditions optimized for mass spectrometry, PAEKI and capillary electrophoresis, detection limits defined as three times ratio of signal to noise have been achieved in a range of 0.013-0.12 μg L(-1) for ten HAAs in water sample. The overall recoveries for all ten HAAs in drinking water samples were between 76 and 125%. Six HAAs including monochloro- (MCAA), dichloro- (DCAA), trichloro- (TCAA), monobromo- (MBAA), bromochloro- (BCAA), and bromodichloroacetic acids (BDCAA) were found in tap water samples collected.

  18. [Determination of serum proteins by high performance capillary zone electrophoresis].

    PubMed

    Zhang, N; Tang, Y; Hao, D M; Zheng, L; Qiu, G B

    1999-11-01

    The separation method of serum proteins was established with an untreared 50 microns i.d. x 47 cm (40 cm to detector) capillary and detection of absorbance at 200 nm. Analysis was performed by pressure injectction 17.23 kPa.s and by applying 23 kV in the constant voltage mode. Serum samples were diluted 40-folds with assay buffer (12.5 mmol/L sodium borate, 1 mmol/L calcium lactate, 0.7 mmol/L magnesium sulfate, 1 mmol/L EDTA were mixed). A normal control serum protein was separated into 6 fractions. In pregnant serum, the alpha 0 was an additionally unknown fraction. Comparison of capillary electrophoresis with conventional cellulose acetate electrophoresis for analysis of serum proteins from normal control, pregnant women multiple myeloma and tonic rachitis patients indicates that capillary clectrophoresis is a new technique for the analysis of serum proteins because of its high efficiency, on-line data processing and automation. Capillary electrophoresis is the reliable technique for clinical diagnosis of serum protein abnormalities.

  19. Microchip capillary electrophoresis of nitrite and nitrate in cerebrospinal fluid.

    PubMed

    Masár, Marián; Bodor, Róbert; Troška, Peter

    2015-01-01

    Microchip capillary electrophoresis (MCE) is a relatively new analytical method requiring only small sample amounts, which is very favorable for the analysis of volume-limited biofluids. The practical use of MCE in bioanalysis is still restricted in terms of requirements for simplifying and/or concentrating sample pretreatment techniques. Here, we describe an MCE method for trace analysis of nitrite and nitrate, indicators of various neurological diseases, in cerebrospinal fluid (CSF). The complex CSF samples were simplified by solid-phase microextraction prior to an online combination of isotachophoresis with capillary zone electrophoresis performed on a microchip with coupled channels and a high-volume sample injection channel (9.9 μL). The method is suitable for rapid (total analysis time lasted 20 min), reproducible (0.6-2.4 % RSD for migration time), and sensitive (3-9 nM limits of detection) determinations of nitrite and nitrate in 15-50 times diluted CSF samples. PMID:25673480

  20. Microchip capillary electrophoresis of nitrite and nitrate in cerebrospinal fluid.

    PubMed

    Masár, Marián; Bodor, Róbert; Troška, Peter

    2015-01-01

    Microchip capillary electrophoresis (MCE) is a relatively new analytical method requiring only small sample amounts, which is very favorable for the analysis of volume-limited biofluids. The practical use of MCE in bioanalysis is still restricted in terms of requirements for simplifying and/or concentrating sample pretreatment techniques. Here, we describe an MCE method for trace analysis of nitrite and nitrate, indicators of various neurological diseases, in cerebrospinal fluid (CSF). The complex CSF samples were simplified by solid-phase microextraction prior to an online combination of isotachophoresis with capillary zone electrophoresis performed on a microchip with coupled channels and a high-volume sample injection channel (9.9 μL). The method is suitable for rapid (total analysis time lasted 20 min), reproducible (0.6-2.4 % RSD for migration time), and sensitive (3-9 nM limits of detection) determinations of nitrite and nitrate in 15-50 times diluted CSF samples.

  1. Determination of synthetic food dyes by capillary electrophoresis.

    PubMed

    Suzuki, S; Shirao, M; Aizawa, M; Nakazawa, H; Sasa, K; Sasagawa, H

    1994-10-01

    A method for the determination of synthetic tar dyes used as food additives using capillary electrophoresis with photodiode-array detection was investigated. The dyes Erythrosine (R-3), Phloxine (R-104), Rose Bengal (R-105), Acid Red (R-106), Amaranth (R-2), New Coccine (R-102) and Allura Red AC (R-40) were separated on a capillary column (50 cm x 75 microns I.D.) and identified from the absorbance spectra of each peak. The electrophoresis buffer used was a mixture of 25 mM sodium phosphate buffer and 25 mM sodium borate buffer (1:1) (pH 8.0) containing 10 mM sodium dodecyl sulfate (SDS). Substitution of beta-cyclodextrin for SDS in the electrolyte buffer was effective for the separation of R-2 and R-102. This modified method could be employed as an additional assay method for these two dyes.

  2. Gene analysis of multiple oral bacteria by the polymerase chain reaction coupled with capillary polymer electrophoresis.

    PubMed

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

    2016-03-01

    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. PMID:26648455

  3. Identification of chiral drug isomers by capillary electrophoresis.

    PubMed

    Fanali, S

    1996-05-31

    Separation of optical isomers of compounds of pharmaceutical interest by capillary electrophoretic techniques is reviewed. The direct and indirect separation method, as well as the main resolution mechanisms and the parameters influencing the stereoselectivity are discussed considering capillary zone electrophoresis, micellar electrokinetic chromatography, isotachophoresis and electrochromatography. Several chiral selectors have been successfully used in CE for chiral separation, including cyclodextrins and their derivatives, modified crown-ethers, proteins, antibiotics, linear saccharides and chiral surfactants. Only applications in the pharmaceutical field with the most important experimental conditions are summarised in the Tables reported in this paper. The chiral analyses of drugs in real samples like biological fluids or pharmaceutical formulations are also reported.

  4. Lambda-carrageenan: a novel chiral selector for capillary electrophoresis.

    PubMed

    Beck, G M; Neau, S H

    1996-01-01

    Lambda-carrageenan, a linear high molecular weight sulfated polysaccharide, has been employed as a chiral selector in capillary electrophoresis for the separation of enantiomers of weakly basic pharmaceutical compounds. The racemic compounds that were enantioresolved included propranolol, pindolol, tryptophanol, laudanosine and laudanosoline. In addition, the diastereomeric pair of cinchonine and cinchonidine were also resolved. Method conditions such as buffer pH, electrolyte concentration, column temperature, and chiral selector concentration were found to be important for improvement of enantioselectivity.

  5. Fast methods for analysis of neurotransmitters from single cell and monitoring their releases in central nervous system by capillary electrophoresis, fluorescence microscopy and luminescence imaging

    SciTech Connect

    Wang, Ziqiang

    1999-12-10

    Fast methods for separation and detection of important neurotransmitters and the releases in central nervous system (CNS) were developed. Enzyme based immunoassay combined with capillary electrophoresis was used to analyze the contents of amino acid neurotransmitters from single neuron cells. The release of amino acid neurotransmitters from neuron cultures was monitored by laser induced fluorescence imaging method. The release and signal transduction of adenosine triphosphate (ATP) in CNS was studied with sensitive luminescence imaging method. A new dual-enzyme on-column reaction method combined with capillary electrophoresis has been developed for determining the glutamate content in single cells. Detection was based on monitoring the laser-induced fluorescence of the reaction product NADH, and the measured fluorescence intensity was related to the concentration of glutamate in each cell. The detection limit of glutamate is down to 10{sup {minus}8} M level, which is 1 order of magnitude lower than the previously reported detection limit based on similar detection methods. The mass detection limit of a few attomoles is far superior to that of any other reports. Selectivity for glutamate is excellent over most of amino acids. The glutamate content in single human erythrocyte and baby rat brain neurons were determined with this method and results agreed well with literature values.

  6. Capillary Electrophoresis of Mono- and Oligosaccharides.

    PubMed

    Toppazzini, Mila; Coslovi, Anna; Rossi, Marco; Flamigni, Anna; Baiutti, Edi; Campa, Cristiana

    2016-01-01

    This chapter reports an overview of the recent advances in the analysis of mono- and oligosaccharides by capillary electrophoresis (CE); furthermore, relevant reviews and research articles recently published in the field are tabulated. Additionally, pretreatments and procedures applied to uncharged and acidic carbohydrates (i.e., monosaccharides and lower oligosaccharides carrying carboxylate, sulfate, or phosphate groups) are described.Representative examples of such procedures are reported in detail, upon describing robust methodologies for the study of (1) neutral oligosaccharides derivatized by reductive amination and by formation of glycosylamines; (2) sialic acid derivatized with 2-aminoacridone, released from human serum immunoglobulin G; (3) anomeric couples of neutral glycosides separated using borate-based buffers; (4) unsaturated, underivatized oligosaccharides from lyase-treated alginate. PMID:27645743

  7. Dating silk by capillary electrophoresis mass spectrometry.

    PubMed

    Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

    2011-10-01

    A new capillary electrophoresis mass spectrometry (CE-MS) technique is introduced for age estimation of silk textiles based on amino acid racemization rates. With an L to D conversion half-life of ~2500 years for silk (B. mori) aspartic acid, the technique is capable of dating silk textiles ranging in age from several decades to a few-thousand-years-old. Analysis required only ~100 μg or less of silk fiber. Except for a 2 h acid hydrolysis at 110 °C, no other sample preparation is required. The CE-MS analysis takes ~20 min, consumes only nanoliters of the amino acid mixture, and provides both amino acid composition profiles and D/L ratios for ~11 amino acids.

  8. Applications of capillary electrophoresis in biotechnology.

    PubMed

    Lagu, A L

    1999-10-01

    Capillary electrophoresis (CE)-related techniques are increasingly being used as a matter of routine practice in the biotechnology discipline. Since recombinant DNA-derived proteins and the antisense oligonucleotides constitute a large portion of the applications of these techniques, they have been emphasized in this review. Analyses by CE of Escherichia coli-derived proteins and glycosylated proteins derived from mammalian cell cultures are summarized, as well as those of the carbohydrate chains that have been enzymatically removed from the protein. Applications of CE in the analysis of the antisense oligonucleotides for the determination of purity and the analytical studies on the metabolism of these modified oligonucleotides, by CE are reviewed. The literature mainly covers the period from 1996. PMID:10596822

  9. High resolution detection system of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Wang, Li Qiang; Shi, Yan; Zheng, Hua; Lu, Zu Kang

    2007-12-01

    The capillary electrophoresis (CE) with laser induced fluorescence detection (LIFD) system was founded according to confocal theory. The 3-D adjustment of the exciting and collecting optical paths was realized. The photomultiplier tube (PMT) is used and the signals are processed by a software designed by ourselves. Under computer control, high voltage is applied to appropriate reservoirs and to inject and separate DNA samples respectively. Two fluorescent dyes Thiazole Orange (TO) and SYBR Green I were contrasted. With both of the dyes, high signals-to-noise images were obtained with the CE-LIFD system. The single-bases can be distinguished from the electrophoretogram and high resolution of DNA sample separation was obtained.

  10. Differentiation of enantiomers by capillary electrophoresis.

    PubMed

    Scriba, Gerhard K E

    2013-01-01

    Capillary electrophoresis (CE) has matured to one of the major liquid phase enantiodifferentiation techniques since the first report in 1985. This can be primarily attributed to the flexibility as well as the various modes available including electrokinetic chromatography (EKC), micellar electrokinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC). In contrast to chromatographic techniques, the chiral selector is mobile in the background electrolyte. Furthermore, a large variety of chiral selectors are available that can be easily combined in the same separation system. In addition, the migration order of the enantiomers can be adjusted by a number of approaches. In CE enantiodifferentiations the separation principle is comparable to chromatography while the principle of the movement of the analytes in the capillary is based on electrophoretic phenomena. The present chapter will focus on mechanistic aspects of CE enantioseparations including enantiomer migration order and the current understanding of selector-selectand structures. Selected examples of the basic enantioseparation modes EKC, MEKC, and MEEKC will be discussed. PMID:23666080

  11. Validation of STR typing by capillary electrophoresis.

    PubMed

    Moretti, T R; Baumstark, A L; Defenbaugh, D A; Keys, K M; Brown, A L; Budowle, B

    2001-05-01

    With the use of capillary electrophoresis (CE), high-resolution electrophoretic separation of short tandem repeat (STR) loci can be achieved in a semiautomated fashion. Laser-induced detection of fluorescently labeled PCR products and multicolor analysis enable the rapid generation of multilocus DNA profiles. In this study, conditions for typing PCR-amplified STR loci by capillary electrophoresis were investigated using the ABI Prism 310 Genetic Analyzer (Applied Biosystems). An internal size standard was used with each run to effectively normalize mobility differences among injections. Alleles were designated by comparison to allelic ladders that were run with each sample set. Multiple runs of allelic ladders and of amplified samples demonstrate that allele sizes were reproducible, with standard deviations typically less than 0.12 bases for fragments up to 317 bases in length (largest allele analyzed) separated in a 47 cm capillary. Therefore, 99.7% of all alleles that are the same length should fall within the measurement error window of +/- 0.36 bases. Microvariants of the tetranucleotide repeats were also accurately typed by the analytical software. Alleles differing in size by one base could be resolved in two-donor DNA mixtures in which the minor component comprised > or = 5% of the total DNA. Furthermore, the quantitative data format (i.e., peak amplitude) can in some instances assist in determining individual STR profiles in mixed samples. DNA samples from previously typed cases (typed for RFLP, AmpliType PM+DQA1, and/or D1S80) were amplified using AmpFlSTR Profiler Plus and COfiler and were evaluated using the ABI Prism 310. Most samples yielded typable results. Compared with previously determined results for other loci, there were no discrepancies as to the inclusion or exclusion of suspects or victims. CE thus provides efficient separation, resolution, sensitivity and precision, and the analytical software provides reliable genotyping of STR loci. The

  12. Determination of benzylpenicillin in pharmaceuticals by capillary zone electrophoresis

    SciTech Connect

    Hoyt, A.M. Jr. ); Sepaniak, M.J. )

    1989-04-01

    A rapid and direct method is described for the determination of benzylpenicillin (penicillin G) in pharmaceutical preparations. The method involves very little sample preparation and total analysis time for duplicate results is less 30 minutes per sample. The method takes advantage of the speed and separating power of capillary zone electrophoresis (CZE). Detection of penicillin is by absorption at 228 nm. An internal standard is employed to reduce sample injection error. The method was applied successfully to both tablets and injectable preparations. 14 refs., 5 figs., 3 tabs.

  13. Response surface methodology in the development of a stacking-sensitive capillary electrophoresis method for the analysis of tricyclic antidepressants in human serum.

    PubMed

    Galeano-Díaz, Teresa; Acedo-Valenzuela, María-Isabel; Mora-Díez, Nielene; Silva-Rodríguez, Antonio

    2005-09-01

    Stacking methods are very important in overcoming the poor detection limits in capillary electrophoresis (CE). In this paper, the separation and determination of several tricyclic antidepressants by a stacking method is described. The inclusion of acetonitrile (ACN) in the sample causes stacking (transient pseudoisotachophoresis) especially in presence of sodium chloride. An experimental design (central composite design) together with the response surface methodology has been used to find the optimum composition of the separation buffer and the optimal stacking conditions in few experiments. The response functions used are the product of the total resolution by the number of peaks, for the optimization of the separation buffer, and the product of the total resolution by the mean of the peak heights, for the optimization of the stacking conditions. About 28% of the capillary volume is loaded with sample. The calibration curves are linear over the working range (50-300 ng/mL). With a bubble capillary, the limits of detection (LODs) are in the order of 5 ng/mL. For the analysis of serum samples, enrichment with sodium chloride and the protein precipitation with ACN are enough to avoid interferences and to get stacking. Recoveries between 91.6 and 104% and RSD between 0.6 and 12% are obtained in the analysis of samples of lyophilized human serum and non-lyophilized human serum, spiked with the drugs.

  14. Analysis of venlafaxine by capillary zone electrophoresis.

    PubMed

    Fanali, S; Cotichini, V; Porrà, R

    1997-01-01

    Capillary electrophoresis has been used for the separation of venlafaxine and two of its impurities deriving from the synthesis process. The electrophoretic experiments were performed using background electrolytes at different pHs in the 2.5-9.2 range in order to study the effective mobilities and resolution of the three examined compounds. The optimum experimental conditions for the baseline resolution of the three analytes was found at pH 6.5. Very good repeatability for both migration time and corrected peak areas was achieved. The calibration curve was studied for venlafaxine (concentration range 26-224 micrograms/mL), and the plot of the peak area ratio (sample/internal standard [IS]) versus venlafaxine concentration was linear with a correlation coefficient of 0.9991. The effect of different cyclodextrins (CDs), namely, gamma-cyclodextrin (gamma-CD), hydroxypropyl-beta-CD (HP-beta-CD), and alpha-cyclodextrin (alpha-CD), on effective mobility and enantiomeric resolution (R) of venlafaxine (Wy45030) and its impurities (imp1 and imp2) was studied at different pHs, and the best results were obtained at pH 9.2. Venlafaxine was baseline resolved in its enantiomers using gamma-CD or HP-beta-CD, while imp1 (Wy45494) was baseline resolved using alpha-CD.

  15. Fabricating PFPE Membranes for Capillary Electrophoresis

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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).

  16. Simultaneous determination of saccharin and aspartame in commercial noncaloric sweeteners using the PLS-2 multivariate calibration method and validation by capillary electrophoresis.

    PubMed

    Cantarelli, Miguel A; Pellerano, Roberto G; Marchevsky, Eduardo J; Camiña, José M

    2008-10-22

    A new method to determine a mixture for sweetener sodium saccharin and aspartame in commercial noncaloric sweeteners is proposed. A classical full factorial design for standards was used in the calibration step to build the partial least-squares (PLS-2) model. Instrumental data were obtained by means of UV-visible spectrophotometry. Salicylic acid was used as an internal standard to evaluate the adjustment of the real samples to the PLS model. The concentration of analytes in the commercial samples was evaluated using the obtained model by UV spectral data. The PLS-2 method was validated by capillary zone electrophoresis (CZE), finding in all cases a relative error of less than 11% between the PLS-2 and the CZE methods. The proposed procedure was applied successfully to the determination of saccharin and aspartame in noncaloric commercial sweeteners.

  17. Use of capillary electrophoresis to study methylation patterns in DNA

    NASA Astrophysics Data System (ADS)

    Voss, Karl; Roos, Pieter; Zhang, Jian Z.; Dovichi, Norman J.

    1996-04-01

    A four-color multiple capillary DNA sequencer is used to determine the methylation pattern of double stranded DNA. The DNA sample is treated with bisulfite under conditions that convert cytosine to uracil. Methyl-cytosine is inert under these reaction conditions. After PCR amplification, the reaction products are subjected to a four-color fluorescent Sanger sequencing reaction. The sequence is then determined by use of capillary electrophoresis. Comparison of the sequence obtained after bisulfite treatment with the original sequence reveals that certain of the Cs in the original sequence are converted to Ts. This conversion occurs only if the original C was not methylated. Those Cs that are common to both sequences were methylated in the original sequence. Methylation patterns have been implicated in aging, developmental biology, and cancer; however, there has been no simple and rapid method for determining the methylation pattern in genomic DNA. The method described in this paper is quick, simple, and accurate, and demonstrates an exciting application of capillary electrophoresis DNA sequencing.

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

    PubMed

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

    2016-09-01

    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. PMID:27475442

  19. ANALYSIS OF THE ENANTIOMERS OF CHIRAL PESTICIDES AND OTHER POLLUTANTS IN ENVIRONMENTAL SAMPLES BY CAPILLARY ELECTROPHORESIS

    EPA Science Inventory

    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...

  20. Capillary Electrophoresis Profiles and Fluorophore Components of Humic Acids in Nebraska Corn and Philippine Rice Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As humic substances represent relatively high molecular mass polyelectrolytes containing aromatic, aliphatic and heterocyclic subunits, capillary electrophoresis (CE) has become an attractive method for “finger-print” characterization of humic acids. In addition, fluorescence excitation-emission ma...

  1. [Annual review of capillary electrophoresis technology in 2015].

    PubMed

    Wang, Xiaoqian; Zhao, Xinying; Liu, Pinduo; Wei, Qiang; Qu, Feng

    2016-02-01

    This paper reviews the capillary electrophoresis (CE) in 2015. The literatures searched from ISI Web of Science ranged in 2015. 1. 1-2015. 12. 31 are classified and introduced based on CE-MS method, methodology research, detection and enrichment, chiral separation and basic applications of CE. Six international and two national conferences are included and the important reports are introduced briefly. In the end, the standards of CE method for the analyses of monoclonal antibodies, water, wines and food approved in China and some other countries are listed. PMID:27382715

  2. A green capillary zone electrophoresis method for the simultaneous determination of piperacillin, tazobactam and cefepime in pharmaceutical formulations and human plasma.

    PubMed

    Al-Attas, Amirah; Nasr, Jenny Jeehan; El-Enany, Nahed; Belal, Fathalla

    2015-12-01

    A green, novel, rapid, accurate and reliable capillary zone electrophoresis method was developed and validated for the simultaneous determination of piperacillin, tazobactam and cefepime in pharmaceutical preparations. Separation was carried out using fused silica capillary (50 µm i.d. × 48.6 cm and 40.2 cm detection length) and applied potential of 20 kV (positive polarity) and a running buffer containing 15 m m sodium borate buffer adjusted to pH 9.3 with UV detection at 215 nm. Amoxicillin was used as an internal standard. The method was suitably validated according to International Conference on Harmonization guidelines. The method showed good linearity in the ranges of 10-100, 20-400 and 10-400 µg/mL with limits of quantitation of 1.87, 3.17 and 6.97 µg/mL and limits of detection of 0.56, 0.95 and 2.09 µg/mL for tazobactam, piperacillin and cefepime, respectively. The proposed method was successfully applied for the analysis of these drugs in their synthetic mixtures and co-formulated injection vials. The method was extended to the in vitro determination of the two drugs in spiked human plasma. It is considered a 'green' method as it consumes no organic solvents. PMID:26058453

  3. Capillary zone electrophoresis and capillary electrophoresis-mass spectrometry for analyzing qualitative and quantitative variations in therapeutic albumin.

    PubMed

    Marie, Anne-Lise; Przybylski, Cédric; Gonnet, Florence; Daniel, Régis; Urbain, Rémi; Chevreux, Guillaume; Jorieux, Sylvie; Taverna, Myriam

    2013-10-24

    The present study describes a reproducible and quantitative capillary zone electrophoresis (CZE) method, which leads to the separation of nine forms (native, oxidized and glycated) of human serum albumin (HSA). In an attempt to identify the different species separated by this CZE method, the capillary electrophoresis was coupled to mass spectrometry using a sheath liquid interface, an optimized capillary coating and a suitable CE running buffer. CE-MS analyses confirmed the heterogeneity of albumin preparation and revealed new truncated and modified forms such as Advanced Glycation End products (AGEs). Assignment of the CZE peaks was carried out using specific antibodies, carboxypeptidase A or sample reduction before or during the CE separation. Thus, five HSA forms were unambiguously identified. Using this CZE method several albumin batches produced by slightly different fractionation ways could be discriminated. Furthermore, analyses of HSA preparations marketed by five pharmaceutical industries revealed that two therapeutic albumins, including that marketed by LFB, contained the highest proportion of native form and lower levels of oxidized forms. PMID:24120174

  4. Capillary zone electrophoresis-mass spectrometry of peptides and proteins

    SciTech Connect

    Loo, J.A.; Udseth, H.R.; Smith, R.D.

    1989-05-01

    Capillary zone electrophoresis (CZE) is attracting extensive attention as a fast, high resolution analytical and micro-preparative separations technique for systems of biological interest. In zone electrophoresis, a column is filled with a single electrolyte having a specific conductivity. The mixture of substances to be separated is applied as a narrow band to the head of a buffer filled column in a band whose width is much less than the length of the column and at a concentration too low to affect the buffer conductivity. An electric field is then applied across the length of the column and the individual substances migrate and separate according to their net electrophoretic velocities. Zone electrophoresis carried out in small diameter (<100 ..mu..m) fused silica capillaries is a relatively new approach to the high resolution separation of aqueous samples. Very small volume samples (picoliter range) with separation efficiencies on the order of 10/sup 6/ theoretical plates for amino acids have been achieved. The method can be further enhanced by the dynamic combination of detection sensitivity and selectivity offered by mass spectrometry (MS). The on-line marriage of mass spectrometry to CZE is accomplished by an atmospheric pressure electrospray ionization source interface. Our research efforts have demonstrated that proteins with MW's greater than 100 kDa can be analyzed using a conventional quadrupole mass spectrometer with an upper m/z limit of only 1700. 6 refs.

  5. Capillary array electrophoresis using laser-excited confocal fluorescence detection

    SciTech Connect

    Huang, X.C.; Quesada, M.A.; Mathies, R.A.

    1992-04-15

    Capillary electrophoresis (CE) has found widespread application in analytical and biomedical research, and the scope and sophistication of CE is still rapidly advancing. Gel-filled capillaries have been employed for the rapid separation and analysis of synthetic polynucleotides, DNA sequencing fragments, and DNA restriction fragments. Open-tube capillary electrophoresis has attained subattomole detection levels in amino acid separations 14 and proven its utility for the separation of proteins, viruses, and bacteria. Separation of the optical isomers of dansyl amino acids has also been successfully demonstrated. Micellar electrokinetic capillary chromatography, isoelectric focusing, and on-column derivatization can all be performed on CE columns, demonstrating the utility of capillary electrophoresis as an analytical and micropreparative tool. 29 refs., 6 figs., 1 tab.

  6. PNEUMATIC MICROVALVE FOR ELECTROKINETIC SAMPLE PRECONCENTRATION AND CAPILLARY ELECTROPHORESIS INJECTION

    SciTech Connect

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

    2014-10-27

    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.

  7. Enantioselective determination by capillary electrophoresis with cyclodextrins as chiral selectors.

    PubMed

    Fanali, S

    2000-04-14

    This review surveys the separation of enantiomers by capillary electrophoresis using cyclodextrins as chiral selector. Cyclodextrins or their derivatives have been widely employed for the direct chiral resolution of a wide number of enantiomers, mainly of pharmaceutical interest, selected examples are reported in the tables. For method optimisation, several parameters influencing the enantioresolution, e.g., cyclodextrin type and concentration, buffer pH and composition, presence of organic solvents or complexing additives in the buffer were considered and discussed. Finally, selected applications to real samples such as pharmaceutical formulations, biological and medical samples are also discussed.

  8. Direct methods for dynamic monitoring of secretions from single cells by capillary electrophoresis and microscopy with laser-induced native fluorescence detection

    SciTech Connect

    Tong, W.

    1997-10-08

    Microscale separation and detection methods for real-time monitoring of dynamic cellular processes (e.g., secretion) by capillary electrophoresis (CE) and microscopic imaging were developed. Ultraviolet laser-induced native fluorescence (LINF) provides simple, sensitive and direct detection of neurotransmitters and proteins without any derivatization. An on-column CE-LINF protocol for quantification of the release from single cell was demonstrated. Quantitative measurements of both the amount of insulin released from and the amount remaining in the cell ({beta}TC3) were achieved simultaneously. Secretion of catecholamines (norepinephrine (NE) and epinephrine (E)) from individual bovine adrenal chromaffin cells was determined using the on-column CE-LINF. Direct visualization of the secretion process of individual bovine adrenal chromaffin cells was achieved by LINF imaging microscopy with high temporal and spatial resolution. The secretion of serotonin from individual leech Retzius neurons was directly characterized by LINF microscopy with high spatial resolution.

  9. Metabolomic profiling of anionic metabolites by capillary electrophoresis mass spectrometry.

    PubMed

    Soga, Tomoyoshi; Igarashi, Kaori; Ito, Chiharu; Mizobuchi, Katsuo; Zimmermann, Hans-Peter; Tomita, Masaru

    2009-08-01

    We describe a sheath flow capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) method in the negative mode using a platinum electrospray ionization (ESI) spray needle, which allows the comprehensive analysis of anionic metabolites. The material of the spray needle had significant effect on the measurement of anions. A stainless steel spray needle was oxidized and corroded at the anodic electrode due to electrolysis. The precipitation of iron oxides (rust) plugged the capillary outlet, resulting in shortened capillary lifetime. Many anionic metabolites also formed complexes with the iron oxides or migrating nickel ion, which was also generated by electrolysis and moved toward the cathode (the capillary inlet). The metal-anion complex formation significantly reduced detection sensitivity of the anionic compounds. The use of a platinum ESI needle prevented both oxidation of the metals and needle corrosion. Sensitivity using the platinum needle increased from several- to 63-fold, with the largest improvements for anions exhibiting high metal chelating properties such as carboxylic acids, nucleotides, and coenzyme A compounds. The detection limits for most anions were between 0.03 and 0.87 micromol/L (0.8 and 24 fmol) at a signal-to-noise ratio of 3. This method is quantitative, sensitive, and robust, and its utility was demonstrated by the analysis of the metabolites in the central metabolic pathways extracted from mouse liver. PMID:19522513

  10. A new electrode chamber for stable performance in capillary electrophoresis.

    PubMed

    Desiderio, C; Fanali, S; Bocek, P

    1999-03-01

    Prerequisite to running automated sequences of analyses in capillary electrophoresis is a stable performance of the system. The products of the electrode reaction with the running background electrolyte (BGE) may play an important role, since even the neutral products may be driven into the capillary by electroosmosis and may severely deteriorate the stability of the baseline. Here, a simple, inexpensive, and fast procedure is described for improving the stability of the performance of capillary electrophoresis using a modified vial serving as the electrode chamber for the running BGE. The modification is based on creating two separate rooms in the vial, one for the electrode and a second one for the capillary. These two rooms are connected by a cotton plug. When both rooms are filled with the running BGE, the electrolytic connection between the electrode and the capillary is ensured; however, the convective transport of the electrode reaction products into the capillary is practically eliminated.

  11. Enzymophoresis of nucleic acids by tandem capillary enzyme reactor-capillary zone electrophoresis.

    PubMed

    Nashabeh, W; el Rassi, Z

    1992-04-10

    Enzymophoresis with coupled heterogeneous capillary enzyme reactor-capillary zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular capillary enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in capillary zone electrophoresis. The capillary enzyme reactors coupled in series with capillary zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantities of oligonucleotides.

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

    PubMed

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

    2015-05-29

    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%. PMID:25895731

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

    PubMed

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

    2015-05-29

    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%.

  14. In-capillary derivatization and capillary electrophoresis separation of amino acid neurotransmitters from brain microdialysis samples.

    PubMed

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

    2008-09-26

    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.

  15. A fast and sensitive method for the determination of nitrite in human plasma by capillary electrophoresis with fluorescence detection.

    PubMed

    Wang, Xu; Adams, Erwin; Van Schepdael, Ann

    2012-08-15

    Analysis of nitrite, the indicator of nitric oxide (NO) generation in vivo, provides a useful tool to study NO synthesis in vivo. A fast and sensitive fluorometric CE method was developed for determination of nitrite in human plasma through its derivatization with 2,3-diaminonaphthalene (DAN). Nitrite in human plasma was easily reacted with DAN under acid conditions to yield the highly fluorescent 2,3-naphthotriazole (NAT). Fluorescence detection was optimized to achieve subnanomolar detection which allows a direct analysis of plasma samples unlike most CE-UV methods using sample stacking. Acetonitrile was used to remove the protein. Short-end injection and a high voltage (-30 kV) were used to shorten the analysis time. The good separation was achieved with 20 mM borate buffer at pH 9.23. The separation of NAT was obtained within 1.4 min. The deproteinized plasma sample was injected hydrodynamically for 5s at -50 mbar into a 60 cm × 75 μm internal diameter uncoated fused-silica capillary. Excitation wavelength was selected with a broad-band filter (240-400 nm), and the emitted light was measured at 418 nm by the use of a cutoff filter. A good linearity (R(2)=0.9975) was obtained in the range from 2 to 500 nM. The detection limit of nitrite was 0.6 nM in original plasma samples, which is 750 times lower than our previous CE-UV method. The developed fluorometric CE method offers the advantages of more simple system and lower cost compared with the current fluorometric HPLC methods without losing sensitivity. The detected mean nitrite concentration in human plasma by this method was consistent with the most frequently reported values. PMID:22841058

  16. Integration of amperometric sensors for microchip capillary electrophoresis application

    NASA Astrophysics Data System (ADS)

    Dicorato, F.; Moore, E.; Glennon, J.

    2011-08-01

    Capillary electrophoresis is a technique for the separation and analysis of chemical compounds. Techniques adopted from the microchip technology knowledge have led to recent developments of electrophoresis system with integration on microchip. Microchip Capillary Electrophoresis (μCE) systems offer a series of advantages as easy integration for Lab-on-a-chip applications, high performance, portability, speed, minimal solvent and sample requirements. A new technological challenge aims at the development of an economic modular microchip capillary electrophoresis systems using separable and independent units concerning the sensor. In this project we worked on the development of an interchangeable amperometric sensor in order to provide a solution to such electrode passivation and facilitating the use of tailored sensors for specific analyte detection besides. Fluidic chips have been machined from cyclic olefin polymer pallets (Zeonor®) using a micro-injection molding machine.

  17. Capillary electrophoresis-electrochemiluminescence detection method for the analysis of ibandronate in drug formulations and human urine.

    PubMed

    Huang, Yu-Shan; Chen, Shun-Niang; Whang, Chen-Wen

    2011-08-01

    A simple, rapid and sensitive CE method coupled with electrochemiluminescence (ECL) detection for direct analysis of ibandronate (IBAN) has been developed. Using a buffer solution of 20 mM sodium phosphate (pH 9.0) and a voltage of 13.5 kV, separation of IBAN in a 30-cm length capillary was achieved in 3 min. ECL detection was performed with an indium tin oxide working electrode bias at 1.6 V (versus a Pt wire reference) in a 200-mM sodium phosphate buffer (pH 8.0) containing 3.5 mM Ru(bpy)(3)(2+) (where bpy=2,2'-bipyridyl). Derivatization of IBAN prior to CE-ECL analysis was not needed. Linear correlation (r=0.9992, n=7) between ECL intensity and analyte concentration was obtained in the range of 0.25-50 μM IBAN. The LOD of IBAN in water was 0.08 μM. The developed method was applied to the analysis of IBAN in a drug formulation and human urine sample. SPE using magnetic Fe(3)O(4)@Al(2)O(3) nanoparticles as the extraction phase was employed to pretreat the urine sample before CE-ECL analysis. The linear range was 0.2-12.0 μM IBAN in human urine (r=0.9974, n=6). The LOD of IBAN in urine was 0.06 μM. Total analysis time including sample preparation was <1 h. PMID:21793001

  18. Recent Developments in Instrumentation for Capillary Electrophoresis and Microchip-Capillary Electrophoresis

    PubMed Central

    Felhofer, Jessica L.; Blanes, Lucas; Garcia, Carlos D.

    2010-01-01

    Over the last years there has been an explosion in the number of developments and applications of capillary electrophoresis (CE) and microchip-CE. In part, this growth has been the direct consequence of recent developments in instrumentation associated with CE. This review, which is focused on contributions published in the last five years, is intended to complement the papers presented in this special issue dedicated to Instrumentation and to provide an overview on the general trend and some of the most remarkable developments published in the areas of high voltage power supplies, detectors, auxiliary components, and compact systems. It also includes few examples of alternative uses of and modifications to traditional CE instruments. PMID:20665910

  19. Analytical characterization of wine and its precursors by capillary electrophoresis.

    PubMed

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

    2012-08-01

    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.

  20. Use of cyclodextrins in capillary electrophoresis: resolution of tramadol enantiomers.

    PubMed

    Rudaz, S; Veuthey, J L; Desiderio, C; Fanali, S

    1998-11-01

    Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol. Both uncoated and polyacrylamide-coated capillaries were tested for method optimization using either negatively charged or native cyclodextrins (CD) added to the background electrolyte (BGE). The resolution was strongly influenced by the CD type and concentration as well as by the pH and the concentration of the BGE. Among the CDs tested, carboxymethylated-beta-cyclodextrin allowed the baseline separation of tramadol enantiomers. After the method was optimized, it was validated in a coated capillary for enantiomeric analysis of tramadol enantiomers in pharmaceutical formulation, including specificity and elution order, linearity, accuracy and precision, determination of limit of detection (LOD) and quantification (LOQ), enantiomeric purity linearity, freedom from interference, and stability of sample solutions. Precision at the target concentration was less than 2%, with an accuracy higher than 99%. Furthermore, the method was able to detect 0.3% and to quantify 1% of the minor enantiomer in the presence of the major one at the target value.

  1. Rapid Determination of Diclofenac in Pharmaceutical Formulations by Capillary Zone Electrophoresis

    PubMed Central

    Lachmann, Bodo; Kratzel, Martin; Noe, Christian R.

    2012-01-01

    Capillary electrophoresis is competitive to HPLC and other chromatographic methods, predominantly when charged analytes have to be separated. The time of analysis can be reduced by the use of very short capillaries applying a high voltage. In most instruments which are commercially available the so-called ‘short end’ of the capillary can be used for separation, leading to very rapid separations. In this contribution we want to demonstrate this approach by using Diclofenac Sodium as an analyte. PMID:22896818

  2. Chiral Separation of Indapamide Enantiomers by Capillary Electrophoresis

    PubMed Central

    Tero-Vescan, Amelia; Hancu, Gabriel; Oroian, Mihaela; Cârje, Anca

    2014-01-01

    Purpose: Indapamide is probably the most frequently prescribed diuretic drug, generally being used for the treatment of hypertension. It contains a chiral center in its molecule; is marketed as a racemic mixture; but there are rather few studies regarding the pharmacokinetic and the pharmacological effect differences of the two enantiomers. Our aim was the development of a simple, rapid and precise analytical procedure for the chiral separation of indapamide enantiomers. Methods: In this study capillary zone electrophoresis was used for the enantiomeric separation of indapamide using a systematic screening approach involving different native and derivatized; neutral and charged cyclodextrines as chiral selectors. The effects of pH value and composition of the background electrolyte, capillary temperature, running voltage and injection parameters have been investigated. Results: After preliminary analysis a charged derivatized CD, sulfobuthyl ether- β-CD, proved to be the optimum chiral selector for the enantioseparation. Using a buffer solution containing 25 mM disodium hydrogenophosphate – 25 mM sodium didydrogenophosphate and 5 mM sulfobuthyl ether- β-CD as chiral selector at a pH - 7, a voltage of + 25 kV, temperature 15°C and UV detection at 242 nm, we succeeded in the separation of the two enantiomers in approximately 6 minutes, with a resolution of 4.30 and a separation factor of 1.08. Conclusion: Capillary zone electrophoresis using cyclodextrines as chiral selectors proved to be a suitable method for the enantioseparation of indapamide. Our method is rapid, specific, reliable, and cost-effective and can be proposed for laboratories performing indapamide routine analysis. PMID:24754011

  3. An absorption detection approach for multiplexed capillary electrophoresis using a linear photodiode array.

    PubMed

    Gong, X; Yeung, E S

    1999-11-01

    A novel absorption detection method for highly multiplexed capillary electrophoresis is presented for zone electrophoresis and for micellar electrokinetic chromatography. The approach involves the use of a linear photodiode array on which a capillary array is imaged by a camera lens. Either a tungsten lamp or a mercury lamp can be used as the light source such that all common wavelengths for absorption detection are accessible by simply interchanging narrow-band filters. Each capillary spans several diodes in the photodiode array for absorption measurements. Over 100 densely packed capillaries can be monitored by a single photodiode array element with 1024 diodes. The detection limit for rhodamine 6G for each capillary in the multiplexed array is ∼1.8 × 10(-)(8) M injected (S/N = 2). The cross-talk between adjacent capillaries is less than 0.2%. Simultaneous analysis of 96 samples is demonstrated. PMID:21662842

  4. A novel capillary electrophoresis method with pressure assisted field amplified sample injection in determination of thiol collectors in flotation process waters.

    PubMed

    Sihvonen, T; Aaltonen, A; Leppinen, J; Hiltunen, S; Sirén, H

    2014-01-17

    A new capillary electrophoresis method was developed for the quantification of diisobutyldithiophosphate (DTP), diisobutyldithiophosphinate (DTPI) and ethyl and isobutyl xanthates (EX, IBX) all of which are used as thiol collectors in froth flotation. This method uses pressure assisted field amplified sample injection (PA-FASI) to concentrate the analytes at the capillary inlet. The background electrolyte in electrophoretic separation was 60millimolar (mM) from 3-(cyclohexylamino)propane-1-sulfonic acid (CAPS) in 40mM NaOH solution. The similar CAPS electrolyte solution has earlier been used for screening for diuretics that contained sulphonamide and/or carboxylic groups. In this study, the functional groups are xanthate, phosphate and phosphinate. The method was developed using actual flotation process waters. The results showed that the water delivered from the plant did not contain significant amount of collectors; therefore, method development was accomplished by spiking analytes in these waters. Separation of analytes was achieved in 15min. The range of quantification was 0.27-66.6mg/L (R(2) 0.9991-0.9999) for all analytes other than ethyl xanthate, for which the range was 0.09-66.6mg/L (R(2) 0.9999). LOD (S/N=3) and LOQ (S/N=10) values for DTP, DTPI, IBX and EX were 0.05, 0.07, 0.06 and 0.01mg/L and 0.16, 0.25, 0.21 and 0.04mg/L, respectively. No interference from the matrices was observed, when the method was tested at a gold concentrator plant.

  5. Fast and sensitive method to determine parabens by capillary electrophoresis using automatic reverse electrode polarity stacking mode: application to hair samples.

    PubMed

    Sako, Alysson V F; Dolzan, Maressa D; Micke, Gustavo Amadeu

    2015-09-01

    This paper describes a fast and sensitive method for the determination of methyl, ethyl, propyl, and butylparaben in hair samples by capillary electrophoresis using automatic reverse electrode polarity stacking mode. In the proposed method, solutions are injected using the flush command of the analysis software (940 mbar) and the polarity switching is carried out automatically immediately after the sample injection. The advantages compared with conventional stacking methods are the increased analytical frequency, repeatability, and inter-day precision. All analyses were performed in a fused silica capillary (50 cm, 41.5 cm in effective length, 50 μm i.d.), and the background electrolyte was composed of 20 mmol L(-1) sodium tetraborate in 10 % of methanol, pH 9.3. For the reverse polarity, -25 kV/35 s was applied followed by application of +30 kV for the electrophoretic run. Temperature was set at 20 °C, and all analytes were monitored at 297 nm. The method showed acceptable linearity (r (2) > 0.997) in the studied range of 0.1-5.0 mg L(-1), limits of detection below 0.017 mg L(-1), and inter-day, intra-day, and instrumental precision better than 6.2, 3.6, and 4.6 %, respectively. Considering parabens is widely used as a preservative in many products and the reported possibility of damage to the hair and also to human health caused by these compounds, the proposed method was applied to evaluate the adsorption of parabens in hair samples. The results indicate that there is a greater adsorption of methylparaben compared to the other parabens tested and also dyed hairs had a greater adsorption capacity for parabens than natural hairs.

  6. Simultaneous determination of iridoid glycosides and flavanoids in Lamionphlomis rotate and its herbal preparation by a simple and rapid capillary zone electrophoresis method.

    PubMed

    Lü, Wenjuan; Li, Maoxing; Chen, Yonglei; Chen, Hongli; Chen, Xingguo

    2012-02-01

    Iridoid glycosides and flavanoids are two main effective components of Lamiophlomis rotata (Benth.) kudo. However, there is no method for simultaneous analysis of iridoid glycosides and flavanoids in L. rotata and its pharmaceutical preparations. A simple and rapid capillary zone electrophoresis (CZE) method was developed and validated for simultaneous determination of two iridoid glycosides (8-O-acetylshanzhiside methylester and 8-deoxyshanzhiside) and three flavanoids (apigenin, quercetin and luteolin) in L. rotata. Operational variables, such as the voltage, buffer concentration and pH were optimized, the final optimum separation condition was 10 mM sodium tetraborate-20 mM NaH(2) PO(4) (pH 8.5)-15% (v/v) methanol, 238 nm UV detection, 18 kV applied voltage. The linearity and the recovery of the proposed method were very satisfactory (correlation coefficients were 0.9994-0.9998 and the recoveries were 94.5-108.8% for the analytes) and the method allowed analytes in real samples to be determined within 9 min. The proposed CZE method can be used for quality control of iridoid glycosides and flavanoids in L. rotata and its herbal preparation.

  7. Examination of black inkjet printing inks by capillary electrophoresis.

    PubMed

    Król, Małgorzata; Kula, Agnieszka; Wietecha-Posłuszny, Renata; Woźniakiewicz, Michał; Kościelniak, Paweł

    2012-07-15

    Counterfeiting of documents is a common phenomenon in the modern world. A large proportion of forgeries relates to inkjet printed documents. Hence there is an evident need to develop an effective and reliable method for the differentiation and identification of inkjet inks on questioned documents. The aim of the presented study was to investigate the possibility of applying micellar electrokinetic capillary chromatography (MECC) to forensic analysis of inkjet inks extracted from black and white printouts. In order to achieve the above aim, a capillary electrophoresis system equipped with a diode array detector was used. The separation was performed using a fused silica capillary (60/50cm total/effective length, 75μm i.d.) with a background electrolyte composed of 40mM sodium borate, 20mM SDS and 10% (v/v) acetonitrile (pH 9.5) at 25°C and 30kV. Ink samples were extracted from black inkjet printouts with the use of dimethyl sulphoxide (DMSO). Differentiation of inks was based on the number of significant peaks at different wavelengths, the relative migration times and the characteristic UV-Vis spectra. The electropherograms of the inks extracted from paper showed patterns which in most cases were distinctly different from each other. The greatest diversity of electrophoretic profiles was revealed for documents printed by Hewlett-Packard inkjet technology. A database of electrophoretic separation results of inks has been constructed for further forensic use.

  8. Enantiomeric resolution of multiple chiral centres racemates by capillary electrophoresis.

    PubMed

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

    2016-05-01

    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.

  9. Analysis of Common Household Cleaner-Disinfectants by Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Gardner, William P.; Girard, James E.

    2000-10-01

    The use of capillary electrophoresis (CE) as an analytical technique in research, industrial, and commercial laboratories is growing rapidly. It is therefore very important to expose undergraduate instrumental analysis students to capillary electrophoresis. In this report we describe the CE analysis for benzalkonium compounds in common household cleaners and disinfectants. The surfactant nature of the benzalkonium compounds is the key consideration in performing the analysis, and modifications to the CE running buffer must be performed in order to successfully analyze the products. This experiment also illustrates the importance of (i) using peak areas corrected for variations in migration time to improve accuracy and (ii) using internal standards to improve the precision of capillary electrophoresis results.

  10. A rapid and simple capillary electrophoresis method for indirect determination of the biocide 2,2-dibromo-3-nitrilo-propionamide (DBNPA) in cooling waters.

    PubMed

    Shiroma, Letícia S; Marques, Thaís T; Jesus, Dosil P

    2015-01-01

    A capillary zone electrophoresis (CE) method was developed for the determination of the biocide 2,2-dibromo-3-nitrilo-propionamide (DBNPA) in water used in cooling systems. The biocide is indirectly determined by CE measurement of the concentration of bromide ions produced by the reaction between the DBNPA and bisulfite. The relationship between the bromide peak areas and the DBNPA concentrations showed a good linearity and a coefficient of determination (R²) of 0.9997 in the evaluated concentration range of 0-75 μmol L⁻¹. The detection and quantification limits for DBNPA were 0.23 and 0.75 μmol L⁻¹, respectively. The proposed CE method was successfully applied for the analysis of samples of tap water and cooling water spiked with DBNPA. The intra-day and inter-day (intermediary) precisions were lower than 2.8 and 6.2%, respectively. The DBNPA concentrations measured by the CE method were compared to the values obtained by a spectrophotometric method and were found to agree well.

  11. Development of a method for the analysis of drugs of abuse in vitreous humor by capillary electrophoresis with diode array detection (CE-DAD).

    PubMed

    Costa, Jose Luiz; Morrone, Andre Ribeiro; Resende, Rodrigo Ribeiro; Chasin, Alice Aparecida da Matta; Tavares, Marina Franco Maggi

    2014-01-15

    This work presents the development of an analytical method based on capillary electrophoresis with diode array detection for the analysis of drugs of abuse and biotransformation products in vitreous humor. Composition of the background electrolyte, implementation of an online pre-concentration strategy and sample preparation procedures were objects of study. The complete electrophoretic separation of 12 analytes (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), ketamine, cocaine, cocaethylene, lidocaine, morphine, 6-monoacetylmorphine and heroin) and the internal standard N-methyl-1-(3,4-methylenedioxyphenyl)-2-butamine (MBDB) was obtained within 13min of run. The method was validated presenting good linearity (r(2)>0.99), recovery ≥90%, precision better than 12% RSD and acceptable accuracy in the range of 86-118% at three concentration levels (50, 100 and 500ng/mL). LODs and LOQs in the order of 1-5ng/mL and 5-10ng/mL, respectively, were obtained. After validation, the method was applied to eighty-seven vitreous humor samples and the results were compared to those obtained by a liquid chromatography tandem mass spectrometry (LC-MS/MS) screening method, routinely used by the forensic toxicology laboratory of the Sao Paulo State Police, Brazil. Cocaine was detected in 7.1%, cocaethylene in 3.6%, lidocaine in 2.4% and ketamine in 1.2% of the total number of analyzed samples. PMID:24325829

  12. Capillary electrophoresis immunoassay using magnetic beads.

    PubMed

    Chen, Hong-Xu; Busnel, Jean-Marc; Gassner, Anne-Laure; Peltre, Gabriel; Zhang, Xin-Xiang; Girault, Hubert H

    2008-08-01

    Protein A-coated magnetic beads (0.3 mum) have been trapped in a small portion of a neutrally coated capillary (50 mum id). Anti-beta-lactoglobulin (beta-LG) antibodies have then been immobilized on the beads through strong affinity with protein A to subsequently capture beta-LG from model or real samples. Once the immunocomplexes formed at physiological pH, a discontinuous buffer system has been used to release the partners and preconcentrate them by transient ITP. The antigens and antibodies have finally been separated by CZE and detected by UV absorbance. An LOQ of 55 nM has been achieved. This methodology has been applied to quantify native beta-LG in pasteurized and ultra-high-temperature-treated bovine milk. All the described procedures, including immunosorbent preparation, sample extraction, cleanup, preconcentration, and separation are completely automated on a commercial CE instrument. As this CE immunoassay method is simple, rapid, selective, and sensitive, it should be a practical and attractive technology for the analysis of complicated biological samples. PMID:18651703

  13. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles.

    PubMed

    Qu, Haiou; Mudalige, Thilak K; Linder, Sean W

    2016-01-15

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg(-1) of silver nanoparticles and 0.03 μg kg(-1) of ionic silver. Nanoparticles of varied sizes (10-110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low.

  14. Development and Validation of a Micellar Capillary Electrophoresis Method for Determination of IFNβ-1b in Lyophilized Formulation of a Biosimilar Product.

    PubMed

    Dadgarnejad, Manuchehr; Rastegar, Hosein; Ilka, Hooshmand; Shekarchi, Maryam; Adib, Nooshin; Alebouyeh, Mahmood; Keypour, Nadia; Shoeibi, Shahram; Kobarfard, Farzad; Fazeli, Mohammad Reza

    2015-01-01

    Human interferons (IFNs) are key cytokines secreted by immune system. They have several effects such as antiviral and anti tumors activity, activating immune cells and healing of multiple sclerosis. The type IFNs present in humans are α ,β and Υ. IFN β is a polypeptide, normally produced by fibroblasts and seems to be more species-specific than IFN. Structural properties of IFNs are important for their biologic effects. There are a few analytical techniques for separation, identification and determination of IFNs in its formulations such as mass spectroscopy, RP-HPLC and capillary electrophoresis (CE). In this study we used Micellar Electrokinetic Chromatography (MEKC) as a unique mode of CE because of its capability to separate neutral as well as charged solutes. We used sodium tetraborate (Borax) as buffer without any modifier and sodium dodecyl sulfate (SDS) as surfactant. The optimum MECK running buffer consisted of Borate 50 Mm; SDS 20 mM pH =9.6. The validated method was used for determination of the IFN β-1b formulation which is manufactured in Iran. From 9 collected different batches, all of them had acceptable potency as claimed on their label with average 102.25 ±10.030 %. This is the first time that a MEKC method is introduced for quantification of IFN β-1b in its pharmaceutical dosage forms. The method is reliable safe, rapid and accurate. PMID:26330863

  15. Experimental design-based development and single laboratory validation of a capillary zone electrophoresis method for the determination of the artificial sweetener sucralose in food matrices.

    PubMed

    McCourt, Josephine; Stroka, Joerg; Anklam, Elke

    2005-07-01

    A capillary zone electrophoresis (CZE) method, optimised chemometrically, underwent a complete in-house validation protocol for the qualification and quantification of sucralose in various foodstuffs. Separation from matrix components was obtained in a dinitrobenzoic acid (3 mM)/sodium hydroxide (20 mM) background electrolyte with a pH of 12.1, a potential of 0.11 kV cm(-1) and a temperature of 22 degrees C. Detection was achieved at 238 nm by indirect UV. Screening, optimisation and robustness testing were all carried out with the aid of experimental design. Using standard addition calibration, the CZE method has been applied to still, carbonated and alcoholic beverages, yoghurts and hard-boiled candy. The method allows the detection of sucralose at >30 mg kg(-1), with a linearity range of 50-500 mg kg(-1), making it suitable for implementation of the recently amended "Sweeteners for use in foodstuffs" Directive (European Parliament and Council (2003) Off J L237:3-12), which set maximum usable doses of sucralose for many foodstuffs, most ranging from 200 mg kg(-1) to 450 mg kg(-1).

  16. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles

    PubMed Central

    Qu, Haiou; Mudalige, Thilak K.; Linder, Sean W.

    2016-01-01

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg−1 of silver nanoparticles and 0.03 μg kg−1 of ionic silver. Nanoparticles of varied sizes (10–110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low. PMID:26724893

  17. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles.

    PubMed

    Qu, Haiou; Mudalige, Thilak K; Linder, Sean W

    2016-01-15

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg(-1) of silver nanoparticles and 0.03 μg kg(-1) of ionic silver. Nanoparticles of varied sizes (10-110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low. PMID:26724893

  18. Determining eight colorants in milk beverages by capillary electrophoresis.

    PubMed

    Huang, Hsi-Ya; Shih, Ying-Chieh; Chen, Yun-Chieh

    2002-06-14

    Milk beverages are popular because of their high nutritional value, and milk products that are enhanced with various fruit flavors are especially in high demand in Asia. Colorants are usually added to fruit flavored milk in order to increase its attraction and appearance, therefore, the detection and measurement of colorants in this type of beverage are relatively important for health issue reasons. Carminic acid, a natural colorant, along with tartrazine, Fast green FCF, Brilliant blue FCF, Allura Red AC, Indigo carmine, Sunset yellow FCF, and New coccine, which are seven different synthetic food colorants, are commonly used as food additives, therefore, this study would focus on the development of an analytical method for the detection of these common colorants in milk beverages. A high efficiency capillary electrophoresis separation method was finished by a pH 10.0 running buffer containing 7.0 mM beta-cyclodextrin, and the eight colorants were separated with baseline resolution within 9 min. In order to reduce the matrix interference resulting from the constituents of milk, a suitable polyamide column solid-phase extraction (SPE) was also investigated for milk sample pretreatment. The combination of the simple SPE pretreatment and the fast separation method of capillary electrophoresis, was able to determine successfully without matrix interference the content of these colorant additives in commercial milk beverages. The recoveries of the eight food colorants in milk beverages were better than 85% and the detection limits were also lower than 0.5 microg/ml by the developed method. PMID:12141558

  19. Capillary electrophoresis-fourier transform ion cyclotron resonance mass spectrometry for the identification of cationic metabolites via a pH-mediated stacking-transient isotachophoretic method.

    PubMed

    Baidoo, Edward E K; Benke, Peter I; Neusüss, Christian; Pelzing, Matthias; Kruppa, Gary; Leary, Julie A; Keasling, Jay D

    2008-05-01

    Capillary electrophoresis-mass spectrometry (CE-MS) is still widely regarded as an emerging tool in the field of metabolomics and metabolite profiling. A major reason for this is a reported lack of sensitivity of CE-MS when compared to gas chromatography-mass spectrometry GC/MS and liquid chromatography-mass spectrometry. The problems caused by the lack of sensitivity are exacerbated when CE is coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), due to the relatively low data acquisition rate of FT-ICR MS. Here, we demonstrate the use of an online CE sample preconcentration method that uses a combination of pH-mediated stacking and transient isotachophoresis, coupled with FT-ICR MS to improve the overall detection of cationic metabolites in the bacterium Desulfovibrio vulgaris Hildenborough. This method showed a significant increase in signal-to-noise ratio when compared to CE normal sample stacking, while providing good separation efficiency, reproducibility, and linearity. Detection limits for selected amino acids were between 0.1 and 2 microM. Furthermore, FT-ICR MS detection consistently demonstrated good mass resolution and sub-ppm mass accuracy.

  20. Internal standard method for the measurement of doxorubicin and daunorubicin by capillary electrophoresis with in-column double optical-fiber LED-induced fluorescence detection.

    PubMed

    Yang, Xiupei; Gao, Huanhuan; Qian, Fan; Zhao, Chuan; Liao, Xiangjun

    2016-01-01

    An internal standard method has been developed for the simultaneous determination of anthracycline antibiotics, doxorubicin (DOX) and daunorubicin (DAN), in rabbit plasma using capillary electrophoresis (CE) with in-column double optical-fiber LED-induced fluorescence detection (CE-ICDOF-LED-FLD). Rhodamine B (RhB) was selected as an internal standard because its emission wavelength is similar to that of the anthracycline antibiotics. Parameters including buffer pH, buffer concentration, organic solvents and separation voltage have been investigated to explore the sensitivity and separation efficiency of DOX and DAN. The optimal electrophoretic separation conditions were a borate buffer (15 mM, pH 9.0) containing 50% acetonitrile (v/v), 10 s hydrodynamic injection at a height of 20 cm and a separation voltage of 15 kV. The developed CE-ICDOF-LED-FLD method provides limits of detection of 18 and 13 ng/mL for DOX and DAN in rabbit plasma samples, respectively. The recoveries ranging from 93.7 to 104.8% and the relative standard deviations at 1.1-1.7% were achieved for DOX and DAN in spiked rabbit plasma samples. PMID:26350558

  1. Capillary zone electrophoresis: an additional technique for the identification of hemoglobin variants.

    PubMed

    Lin, C; Cotton, F; Fontaine, B; Gulbis, B; Janssens, J; Vertongen, F

    1999-05-01

    Two capillary zone electrophoresis kits (Hb A2 and Hb A1c) were tested for confirmation and identification of hemoglobin variants. The capillary zone electrophoresis experiments were performed at pH 4.7 (Hb A1c kit) and 8.7 (Hb A2 kit) in a 24 cm uncoated fused silica capillary tube (25 microm I.D.). Normal hemoglobins and common hemoglobin variants, including Hbs S, D-Punjab, C, E, O-Arab, and G-Philadelphia, were successfully separated by both methods within a few minutes. Both systems provided completely different elution profiles of normal and abnormal hemoglobin fractions tested and were complementary. The inter-assay coefficient of variations of the migration times of hemoglobin variants were less than 1.0 and 1.3% by the Hb A2 and Hb A1c, respectively. This permits a higher resolution of some hemoglobin variants in low concentrations, like Hb S in newborns, compared with conventional electrophoresis methods. The present capillary zone electrophoresis methods are sensitive, rapid, not labor intensive, and highly selective for the separation of hemoglobin variants. Combination of both methods with some conventional methods, such as isoelectrofocusing, allows identification of Hbs C, E, O-Arab, S, and D-Punjab, as well as their quantification. We have demonstrated that the conventional electrophoresis methods (electrophoresis at pH 6.5 in citrate agar gel and electrophoresis at pH 8.6 on cellulose acetate) can be advantageously replaced by the present capillary zone electrophoresis methods in a clinical laboratory practice for the detection and quantification of hemoglobin variants. PMID:10335978

  2. Determination of thioglycolic acid in cosmetics by capillary electrophoresis.

    PubMed

    Xie, Na; Ding, Xiaojing; Wang, Xinyu; Wang, Ping; Zhao, Shan; Wang, Zhi

    2014-01-01

    A new and simple method for the accurate determination of thioglycolic acid (TGA) in cosmetics was developed using capillary electrophoresis (CE) with diode array detection at 236nm. The CE separation was performed on an uncoated fused silica capillary with a separation buffer solution containing 300mmolL(-1) tri-sodium phosphate and 0.5mmolL(-1) cetyltrimethylammonium bromide at a voltage of -5kV. Both the intra- and inter-day precisions of the method were 1.4%. The calibration curve between the corrected peak areas and the concentrations of the TGA was linear within the concentration range of 0.006-1.0mgmL(-1) with a correlation coefficient (r) of 0.9998. The limit of detection and limit of quantitation were 0.002mgmL(-1) (S/N=3) and 0.006mgmL(-1) (S/N=10), respectively. The average recoveries at the spiked levels of 0.125, 0.250 and 0.500mgmL(-1) were 96.9%, 102.3% and 94.0% with the relative standard derivations of 2.1%, 3.9% and 2.2%, respectively. The method was cross-validated by both high performance liquid chromatographic and ion chromatographic method. Eighty-five commercial depilatory creams and hair-treatment products were analyzed with satisfactory results.

  3. Analysis of Anions in Ambient Aerosols by Microchip Capillary Electrophoresis

    SciTech Connect

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

    2006-10-01

    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 µM) and low limits-of-detection for sulfate and nitrate with Au providing the lowest detection limits (1 µM) 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.

  4. Controlling enantioselectivity in chiral capillary electrophoresis with inclusion-complexation.

    PubMed

    Fanali, S

    1997-12-19

    The separation of chiral compounds is of key importance in different fields of application, e.g., pharmaceutical, industrial, forensic, biological, clinical etc. Capillary electrophoresis (CE) is a powerful analytical method applied in chiral analysis and inclusion-complexation is one of the most frequently used mechanism to improve the selectivity of the enantiomeric separation. Cyclodextrins and their derivatives or modified crown-ethers have been successfully applied in CE for the enantiomeric separation of a wide number of analytes. This review surveys the separation of enantiomers by CE when chiral selectors, forming inclusion-complexation, are used. The control of enantioselectivity can be done carefully by considering several experimental parameters such as chiral selector type and concentration, pH, ionic strength and concentration of the background electrolyte, electroosmotic flow, organic modifier etc. The review presents a list of the latest separation of enantiomers by CE where inclusion-complexation plays a key role in the stereoselective separation mechanism.

  5. Separation of ions in acidic solution by capillary electrophoresis

    SciTech Connect

    Thornton, M.

    1997-10-08

    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.

  6. [Determination of glutamic acid in biological material by capillary electrophoresis].

    PubMed

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

    2015-01-01

    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.

  7. [Application of capillary electrophoresis in analysis of intact mammalian cells].

    PubMed

    Zhang, Lu; Qu, Feng; Lou, Beilei

    2012-02-01

    Cell is the basic structural and functional unit of human body. The research of cells' structure, function and behavior is very important. Capillary electrophoresis (CE) is a powerful tool for the separation and analysis, the application of which in cell analysis has progressed significantly. In this paper, the developments of CE applied in the intact mammalian cell analysis are reviewed, which consist of cell population and single cell analysis. The erythrocyte, boar sperm, HeLa cells, SH-SY5Y cells, Caco-2 cells, K562 cells and rat cerebellar granule cells are involved in this review. The methods and conditions for the intact mammalian cell analysis are summarized. In addition, the problems caused by the breakage, aggregation, sedimentation, adsorption and electrophoretic heterogeneity of the cell in the intact mammalian cell analysis by CE are discussed, and the corresponding solutions are introduced. Also, the future research trends are presented. Forty nine papers in all are reviewed.

  8. Capillary electrophoresis of conidia from cultivated microscopic filamentous fungi.

    PubMed

    Horká, Marie; Růzicka, Filip; Kubesová, Anna; Holá, Veronika; Slais, Karel

    2009-05-15

    In immunocompromised people fungal agents are able to cause serious infections with high mortality rate. An early diagnosis can increase the chances of survival of the affected patients. Simultaneously, the fungi produce toxins and they are frequent cause of allergy. Currently, various methods are used for detection and identification of these pathogens. They use microscopic examination and growth characteristic of the fungi. New methods are based on the analysis of structural elements of the target microorganisms such as proteins, polysaccharides, glycoproteins, nucleic acids, etc. for the construction of antibodies, probes, and primers for detection. The above-mentioned methods are time-consuming and elaborate. Here hydrophobic conidia from the cultures of different strains of the filamentous fungi were focused and separated by capillary zone electrophoresis and capillary isoelectric focusing. The detection was optimized by dynamic modifying of conidia by the nonionogenic tenside on the basis of pyrenebutanoate. Down to 10 labeled conidia of the fungal strains were fluorometrically detected, and isoelectric points of conidia were determined. The observed isoelectric points were compared with those obtained from the separation of the cultured clinical samples, and they were found to be not host-specific.

  9. Comparative Study of Three Methods for Affinity Measurements: Capillary Electrophoresis Coupled with UV Detection and Mass Spectrometry, and Direct Infusion Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Mironov, Gleb G.; Logie, Jennifer; Okhonin, Victor; Renaud, Justin B.; Mayer, Paul M.; Berezovski, Maxim V.

    2012-07-01

    We present affinity capillary electrophoresis and mass spectrometry (ACE-MS) as a comprehensive separation technique for label-free solution-based affinity analysis. The application of ACE-MS for measuring affinity constants between eight small molecule drugs [ibuprofen, s-flurbiprofen, diclofenac, phenylbutazone, naproxen, folic acid, resveratrol, and 4,4'-(propane-1,3-diyl) dibenzoic acid] and β-cyclodextrin is described. We couple on-line ACE with MS to combine the separation and kinetic capability of ACE together with the molecular weight and structural elucidation of MS in one system. To understand the full potential of ACE-MS, we compare it with two other methods: Direct infusion mass spectrometry (DIMS) and ACE with UV detection (ACE-UV). After the evaluation, DIMS provides less reliable equilibrium dissociation constants than separation-based ACE-UV and ACE-MS, and cannot be used solely for the study of noncovalent interactions. ACE-MS determines apparent dissociation constants for all reacting small molecules in a mixture, even in cases when drugs overlap with each other during separation. The ability of ACE-MS to interact, separate, and rapidly scan through m/z can facilitate the simultaneous affinity analysis of multiple interacting pairs, potentially leading to the high-throughput screening of drug candidates.

  10. Screening method of carbohydrate-binding proteins in biological sources by capillary affinity electrophoresis and its application to determination of Tulipa gesneriana agglutinin in tulip bulbs.

    PubMed

    Nakajima, Kazuki; Kinoshita, Mitsuhiro; Oda, Yasuo; Masuko, Takashi; Kaku, Hanae; Shibuya, Naoto; Kakehi, Kazuaki

    2004-09-01

    We developed capillary affinity electrophoresis (CAE) to analyze the molecular interaction between carbohydrate chains and proteins in solution state. A mixture of oligosaccharides derived from a glycoprotein was labeled with 8-aminopyrene-1,3,6-trisulfonate (APTS), and used as glycan library without isolation. Interaction of a carbohydrate-binding protein with each oligosaccharide in the mixture could be simultaneously observed, and relative affinities of oligosaccharides toward the protein were accurately determined. In this study, we applied CAE to detect the presence of lectins in some plants (Japanese elderberry bark and tulip bulb). In the crude extract of the elderberry bark, binding activity toward sialo-carbohydrate chains could be easily detected. We also examined the presence of lectins in the crude extract of tulip bulbs and determined the detailed carbohydrate-binding specificity of Tulipa gesneriana agglutinin (TGA), one of the lectins from tulip bulbs. Kinetic studies demonstrated that TGA showed novel carbohydrate-binding specificity and preferentially recognized triantennary oligosaccharides with Gal residues at nonreducing termini and a Fuc residue linked through alpha(1-6) linkage at chitobiose portion of the reducing termini but not tetraantennary carbohydrates. The results described here indicate that CAE will be a valuable method for both screening of lectins in natural sources and determination of their detailed carbohydrate-binding specificities.

  11. Multivariate optimization and validation of a capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromur, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate in a pharmaceutical preparation using response surface methodology.

    PubMed

    Palabiyik, I Murat; Onur, Feyyaz

    2010-01-01

    A fast, accurate, precise and sensitive capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromide, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate has been developed. Response surface methodology with a central composite design was used for optimization of the concentration of the buffer, pH of the buffer and applied voltage. Therefore, working with Na(2)HPO(4) buffer (pH 8.00, 0.01 M) at 20 kV as an applied voltage in the capillary electrophoresis method were found to be suitable; under these optimal conditions, these four active ingredients were separated in about 7 min. This developed method was validated and successfully applied to a pharmaceutical preparation, sugar-coated tablet, and the results were compared with a high-performance liquid chromatographic method developed by us.

  12. An Inexpensive Device for Capillary Electrophoresis with Fluorescence Detection

    ERIC Educational Resources Information Center

    Anderson, Greg; Thompson, Jonathan E.; Shurrush, Khriesto

    2006-01-01

    We describe an inexpensive device for performing capillary electrophoresis (CE) separations with fluorescence detection. As a demonstration of the device's utility we have determined the mass of riboflavin in a commercially available dietary supplement. The device allows for separation of riboflavin in [asymptotically equivalent to] 100 s with a…

  13. CAPILLARY ELECTROPHORESIS IMMUNOASSAY FOR 2,4-DICHLOROPHENOXYACETIC ACID

    EPA Science Inventory

    A capillary electrophoresis (CE) immunoassay format for 2,4-dichlorophenoxyacetic acid (2,4-D) is demonstrated. A fluorescent labeled 2,4-D analog competes with the analyte of interest for a finite number of binding sites provided by anti-2,4-D monoclonal antibodies. CE then pr...

  14. An aluminum heat sink and radiator for electrophoresis capillaries.

    PubMed

    Rapp, T L; Morris, M D

    1996-12-15

    An aluminum heat sink and radiator are used with forced air cooling of an electrophoresis capillary. Theoretical analyses of the operating limits and heat dissipation characteristics are presented. A system designed for power dissipation as high as 5 W is shown to dissipate heat efficiently and to operate without arcing at voltages higher than 30 kV.

  15. Capillary electrophoresis application in metal speciation and complexation characterization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. Capillary zone electrophoresis of inorganic anions with conductivity detection.

    PubMed

    Kaniansky, D; Zelenská, V; Baluchová, D

    1996-12-01

    A carrier electrolyte system for capillary zone electrophoresis (CZE) resolving chloride, bromide, iodide, fluoride, nitrite, nitrate, sulfate, and phosphate in a hydrodynamically closed separation compartment is described. The carrier electrolyte combines the effects of pH, polyvinylpyrrolidone (PVP) and the counterionic constituent on the effective mobilities of the anions. In 300 microns ID capillary tubes made of fluorinated ethylene-propylene copolymer (FEP), and with detection of analytes with the aid of an alternating current conductivity detector, detection limits in the range of 3-10 ppb could be achieved for 200 nL sample volumes. The separation efficiencies were in the range of 1.5-2.5 x 10(5) theoretical plates per meter for an adequate sample load. The reproducibility was evaluated for two concentration levels. For concentrations close to the limits of quantitation (50-120 ppb), the RSD values ranged from 1.5-12.6%, with the highest scatter for fluoride and phosphate. The RSD values were in the range of 0.4-1.5% for 300-1200 ppb concentrations of the anions. Typical analysis times were 2-5 min, depending on the anion species. A series of water samples (drinking, river, rain) was used to assess the practical applicability of the CZE method. The method is a suitable alternative for the determination of both anionic macro- and microconstituents in water with a good overall selectivity.

  17. Capillary electrophoresis of seed 2S albumins from Lupinus species.

    PubMed

    Salmanowicz, B P

    2000-10-13

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

  18. Determination of preservatives in soft drinks by capillary electrophoresis with ionic liquids as the electrolyte additives.

    PubMed

    Sun, Bingbing; Qi, Li; Wang, Minglin

    2014-08-01

    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.

  19. Determination of preservatives in soft drinks by capillary electrophoresis with ionic liquids as the electrolyte additives.

    PubMed

    Sun, Bingbing; Qi, Li; Wang, Minglin

    2014-08-01

    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. PMID:24910409

  20. Acupuncture Sample Injection for Microchip Capillary Electrophoresis and Electrokinetic Chromatography.

    PubMed

    Ha, Ji Won; Hahn, Jong Hoon

    2016-05-01

    A simple nanoliter-scale injection technique was developed for polydimethylsiloxane (PDMS) microfluidic devices to form the well-defined sample plugs in microfluidic channels. Sample injection was achieved by performing acupuncture on a channel with a needle and applying external pressure to a syringe. This technique allowed us to achieve reproducible injection of a 3-nL segment into a microchannel for PDMS microchip-based capillary electrophoresis (CE). Capillary zone electrophoresis (CZE) and capillary electrochromatography (CEC) with bead packing were successfully performed by applying a single potential in the most simplified straight channel. The advantages of this acupuncture injection over the electrokinetic injection in microchip CE include capability of minimizing sample loss and voltage control hardware, capability of serial injections of different sample solutions into a same microchannel, capability of injecting sample plugs into any position of a microchannel, independence on sample solutions during the loading step, and ease in making microchips due to the straight channel, etc. PMID:27056036

  1. Imaging Catalytic Surfaces by Multiplexed Capillary Electrophoresis With Absorption Detection

    SciTech Connect

    Michael Christodoulou

    2002-08-27

    A new technique for in situ imaging and screening heterogeneous catalysts by using multiplexed capillary electrophoresis with absorption detection was developed. By bundling the inlets of a large number of capillaries, an imaging probe can be created that can be used to sample products formed directly from a catalytic surface with high spatial resolution. In this work, they used surfaces made of platinum, iron or gold wires as model catalytic surfaces for imaging. Various shapes were recorded including squares and triangles. Model catalytic surfaces consisting of both iron and platinum wires in the shape of a cross were also imaged successfully. Each of the two wires produced a different electrochemical product that was separated by capillary electrophoresis. Based on the collected data they were able to distinguish the products from each wire in the reconstructed image.

  2. Examination of colour inkjet printing inks by capillary electrophoresis.

    PubMed

    Szafarska, Małgorzata; Wietecha-Posłuszny, Renata; Woźniakiewicz, Michał; Kościelniak, Paweł

    2011-06-15

    The possibility of comparing inkjet printing inks by micellar electrokinetic capillary electrophoresis (MECC) with diode array detection was studied. An analytical procedure was designed and successfully applied to discriminate between the electrophoretic profiles of inks (extracted from paper) produced by five well-known manufacturers. The separation process was conducted in a polyimide-coated fused silica capillary (ID 50 μm, 60 cm total/50 cm effective length) with +30 kV high voltage applied. Background electrolyte was used of the following optimum composition: 40 mM sodium borate buffer, 20mM sodium dodecyl sulphate(IV) (SDS) and 10% (v/v) acetonitrile (pH 9.56). The experimental conditions were adjusted in terms of resolution and analysis time. The best results were obtained at 10 and 25°C storage and capillary temperature, respectively, using 25 dots (ø 0.8mm) cut from printouts as the sample and BGE diluted with water (1:99, v/v) as the injecting solution. The MECC separation of main printing ink components by the proposed method showed excellent precision - the RSD value of the migration time calculated for each of the investigated peaks did not exceed 3.3%. The optimized method was applied to group identification and differentiation of: (a) three colours of printing inks, (b) inks from different manufacturers (Hewlett-Packard, Epson, Brother, Lexmark and Canon) and (c) inks from different printer models. In all these cases, inks were successfully differentiated on the basis of position (migration time) and shape of their characteristic peaks.

  3. Capillary zone electrophoresis for separation and quantitative determination of mexiletine and its main phase I metabolites.

    PubMed

    Bruno, Claudio; Cavalluzzi, Maria Maddalena; Carocci, Alessia; Catalano, Alessia; Franchini, Carlo; Lentini, Giovanni

    2013-03-01

    The simultaneous separation and quantification of the analytes within the minimum analysis time and the maximum resolution and efficiency are the main objectives in the development of a capillary electrophoretic method for the determination of solutes. In this paper we describe a specific, sensitive and robust method, using capillary zone electrophoresis with internal standard and UV detection, for the separation and quantification of the anti-arrhythmic drug mexiletine, its main phase I metabolites, and its main nitrogenous degradation product. PMID:23826880

  4. An integrated quality by design and mixture-process variable approach in the development of a capillary electrophoresis method for the analysis of almotriptan and its impurities.

    PubMed

    Orlandini, S; Pasquini, B; Stocchero, M; Pinzauti, S; Furlanetto, S

    2014-04-25

    The development of a capillary electrophoresis (CE) method for the assay of almotriptan (ALM) and its main impurities using an integrated Quality by Design and mixture-process variable (MPV) approach is described. A scouting phase was initially carried out by evaluating different CE operative modes, including the addition of pseudostationary phases and additives to the background electrolyte, in order to approach the analytical target profile. This step made it possible to select normal polarity microemulsion electrokinetic chromatography (MEEKC) as operative mode, which allowed a good selectivity to be achieved in a low analysis time. On the basis of a general Ishikawa diagram for MEEKC methods, a screening asymmetric matrix was applied in order to screen the effects of the process variables (PVs) voltage, temperature, buffer concentration and buffer pH, on critical quality attributes (CQAs), represented by critical separation values and analysis time. A response surface study was then carried out considering all the critical process parameters, including both the PVs and the mixture components (MCs) of the microemulsion (borate buffer, n-heptane as oil, sodium dodecyl sulphate/n-butanol as surfactant/cosurfactant). The values of PVs and MCs were simultaneously changed in a MPV study, making it possible to find significant interaction effects. The design space (DS) was defined as the multidimensional combination of PVs and MCs where the probability for the different considered CQAs to be acceptable was higher than a quality level π=90%. DS was identified by risk of failure maps, which were drawn on the basis of Monte-Carlo simulations, and verification points spanning the design space were tested. Robustness testing of the method, performed by a D-optimal design, and system suitability criteria allowed a control strategy to be designed. The optimized method was validated following ICH Guideline Q2(R1) and was applied to a real sample of ALM coated tablets.

  5. Capillary electrophoresis procedures for serum protein analysis: comparison with established techniques.

    PubMed

    Jenkins, M A; Guerin, M D

    1997-10-10

    Methods using automated capillary electrophoresis (CE) instrumentation are available for serum protein electrophoresis with monoclonal band quantitation, isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis separations. The advantages of CE over previous gel methods relate to the time and labour saved by the automated instrumentation. High pI monoclonal bands and cryoglobulin specimens can be successfully analysed by CE. However, if the CE application uses a standard company supplied kit, then the cost savings are often negated by the high cost of the kit. Improvements such as the inclusion of both a UV-Vis as well as a fluorescence detector as standard within the one commercial instrument, the production of coated IEF capillaries with a useful life of at least 100 samples, and the introduction of a capillary array into all commercial instrumentation would ensure greater use of CE within both the clinical and other protein laboratories.

  6. Method development and validation for the simultaneous determination of cinnarizine and co-formulated drugs in pharmaceutical preparations by capillary electrophoresis.

    PubMed

    Abdelal, A A; Kitagawa, S; Ohtani, H; El-Enany, N; Belal, F; Walash, M I

    2008-02-13

    Rapid and simple capillary electrophoresis (CE) methods were developed for the simultaneous determinations of cinnarizine and domperidone (CN/DOM) and cinnarizine and nicergoline (CN/NIC) in their co-formulated tablets. The optimized CE conditions were as follows: running buffer, methanol-acetate buffer (pH 3.0, 10 mM) (80:20 and 85:15 (v/v) for CN/DOM and CN/NIC, respectively); applied voltage, 20 kV; UV detection wavelengths, 215 and 227 nm for CN/DOM and CN/NIC, respectively; hydrodynamic injection was performed at a height of 25 mm for 30 s. Quinine hydrochloride and nicardipine hydrochloride were used as internal standards for the determination of CN/DOM and CN/NIC, respectively. Calibration curves were linear over the ranges 0.25-20/0.375-15 microg/ml (CN/DOM) and 0.25-25/0.4-10 microg/ml (CN/NIC) in each optimized condition. Detection limits were 0.074/0.119 microg/ml and 0.072/0.116 microg/ml for CN/DOM and CN/NIC, respectively. The proposed methods were successfully applied for the simultaneous determination of both CN/DOM and CN/NIC in their co-formulated tablets without interfering peaks due to the excipients present in the pharmaceutical tablets. The estimated amounts of CN/DOM and CN/NIC were almost identical with the certified values, and their percentage relative standard deviation values (%R.S.D.) were found to be < or =2.34% (n=3). PMID:18164891

  7. Development and validation of a capillary electrophoresis method for determination of enantiomeric purity and related substances of esomeprazole in raw material and pellets.

    PubMed

    Estevez, Pablo; Flor, Sabrina; Boscolo, Oriana; Tripodi, Valeria; Lucangioli, Silvia

    2014-03-01

    A capillary electrophoresis method using CDs for quality control of esomeprazole (ESO) in terms of enantiomeric purity and related substances in raw material and pellets was developed. ESO is the S-enantiomer of omeprazole (OMZ). Several parameters were evaluated, including type and concentration of buffer and CD, concentration of additives and electrolyte pH. Resolution between the enantiomers of OMZ obtained for each parameter tested was calculated and the presence of the main related substance such as OMZ sulfone was carefully monitored. The optimized system consisted of 100 mM Tris-phosphate buffer pH 2.5 with 20 mM 2-hydroxypropyl-β-CD, 1 mM sodium dithionite, temperature at 15°C, voltage at 28 kV, and UV detection at 301 nm. Once optimized, the electrophoretic system was validated according to ICH guidelines. The limits of detection and quantification for R-OMZ were 0.6 μg/mL (0.06% w/w of ESO) and 2.0 μg/mL (0.2% w/w of ESO), respectively. A mean concentration of R-OMZ <0.2% limit established by the United States Pharmacopeia (USP) was found in the raw material and six-pellet samples of ESO. No other impurities were found in the samples under these conditions. Therefore, the developed method was found to be appropriate not only for enantiomeric quality control of ESO but also for the analysis of ESO and the main related substance in raw material and pharmaceutical formulations as well as for stability indicating studies. PMID:24258683

  8. Development and validation of a capillary electrophoresis method for determination of enantiomeric purity and related substances of esomeprazole in raw material and pellets.

    PubMed

    Estevez, Pablo; Flor, Sabrina; Boscolo, Oriana; Tripodi, Valeria; Lucangioli, Silvia

    2014-03-01

    A capillary electrophoresis method using CDs for quality control of esomeprazole (ESO) in terms of enantiomeric purity and related substances in raw material and pellets was developed. ESO is the S-enantiomer of omeprazole (OMZ). Several parameters were evaluated, including type and concentration of buffer and CD, concentration of additives and electrolyte pH. Resolution between the enantiomers of OMZ obtained for each parameter tested was calculated and the presence of the main related substance such as OMZ sulfone was carefully monitored. The optimized system consisted of 100 mM Tris-phosphate buffer pH 2.5 with 20 mM 2-hydroxypropyl-β-CD, 1 mM sodium dithionite, temperature at 15°C, voltage at 28 kV, and UV detection at 301 nm. Once optimized, the electrophoretic system was validated according to ICH guidelines. The limits of detection and quantification for R-OMZ were 0.6 μg/mL (0.06% w/w of ESO) and 2.0 μg/mL (0.2% w/w of ESO), respectively. A mean concentration of R-OMZ <0.2% limit established by the United States Pharmacopeia (USP) was found in the raw material and six-pellet samples of ESO. No other impurities were found in the samples under these conditions. Therefore, the developed method was found to be appropriate not only for enantiomeric quality control of ESO but also for the analysis of ESO and the main related substance in raw material and pharmaceutical formulations as well as for stability indicating studies.

  9. Fast high-throughput method for the determination of acidity constants by capillary electrophoresis. II. Acidic internal standards.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

    2010-12-24

    A fast method for the determination of acidity constants by CZE has been recently developed. This method is based on the use of an internal standard of pK(a) similar to that of the analyte. In this paper we establish the reference pK(a) values of a set of 24 monoprotic neutral acids of varied structure that we propose as internal standards. These compounds cover the most usual working pH range in CZE and facilitate the selection of adequate internal standards for a given determination. The reference pK(a) values of the acids have been established by the own internal standard method, i.e. from the mobility differences between different acids of similar pK(a) in the same pH buffers. The determined pK(a) values have been contrasted to the literature pK(a) values and confirmed by determination of the pK(a) values of some acids of the set by the classical CE method. Some systematic deviations of mobilities have been observed in NaOH buffer in reference to the other used buffers, overcoming the use of NaOH in the classical CE method. However, the deviations affect in a similar degree to the test compounds and internal standards allowing thus, the use of NaOH buffer in the internal standard method. This fact demonstrates the better performance of the internal standard method over the classical method to correct mobility deviations, which together with its fastness makes it an interesting method for the routine determination of accurate pK(a) values of new pharmaceutical drugs and drug precursors.

  10. Implementation of USP antibody standard for system suitability in capillary electrophoresis sodium dodecyl sulfate (CE-SDS) for release and stability methods.

    PubMed

    Esterman, Abbie L; Katiyar, Amit; Krishnamurthy, Girija

    2016-09-01

    Capillary electrophoresis sodium dodecyl sulfate (CE-SDS) is widely used for purity analysis of monoclonal antibody therapeutics for release and stability to demonstrate product consistency and shelf life during the manufacturing and life cycle of the product. CE-SDS method development is focused on exploring the method capability to provide the information about the product purity and product related degradants (fragmentation, aggregation etc.). In order to establish the functionality of the instrumentation, software, and sample preparation; system suitability criteria need to be defined for analytical methods using a well characterized reference standard run under the same protocol and analysis as the test articles. Typically the reference standard is produced using a manufacturing process representative of the clinical material. The qualification, control, and maintenance of in-house reference standards are established through rigorous quality and regulatory guidelines. The U.S. Pharmacopeia (USP) has developed a monoclonal IgG System Suitability Reference Standard to be utilized for assessment of system suitability in CE-SDS methods. In this communication, we evaluate the system suitability acceptance criteria performance of the USP IgG standard using two methods, the recommended USP protocol provided in monograph <129> and a molecule specific Bristol-Myers Squibb (BMS) CE-SDS method. The results from USP IgG standard were compared with two in-house monoclonal antibody reference standards. The data suggest that the USP CE-SDS method may not be suitable for CE-SDS analysis for release and stability of monoclonal antibody therapeutics due to the high level of method induced partial reduction observed for all molecules tested. This high level of fragmentation observed utilizing the USP method will result in reporting lower purity levels, which will impact the overall quality assessment of the molecule. The system suitability criteria recommended by the USP method

  11. Determination of acidity constants of sparingly soluble drugs in aqueous solution by the internal standard capillary electrophoresis method.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Rosés, Martí

    2014-12-01

    A set of 33 drugs with different solubilities, ranging from soluble to very insoluble, has been chosen in order to evaluate the performance of the internal standard CE method to determine acidity constants of compounds with limited solubility. The set of drugs tested in this work has been chosen as a function of their intrinsic solubility. For the most insoluble compounds, several analytical conditions to overcome the insolubility in aqueous buffers have been tested. This paper assesses the compound solubility limits for the IS-CE method in aqueous pKa determinations, and also compares the determined pKa s with the results from the literature data obtained by other methods. It is proved that IS-CE method determines acidity constants of sparingly soluble drugs in aqueous media (compounds with logS down to around -6), whereas other reference methods require the use of aqueous-organic solvent buffers and extrapolation procedures to obtain the aqueous pKa for the same compounds.

  12. Liquid chromatographic method for determination of water in soils and the optimization of anion separations by capillary zone electrophoresis

    SciTech Connect

    Benz, N.

    1994-10-01

    A liquid chromatographic method for the determination of water in soil or clay samples is presented. In a separate study, the optimization of electrophoretic separation of alkylated phenolate ions was optimized by varying the pH and acetonitrile concentration of the buffer solutions.

  13. Differentiation of opium and poppy straw using capillary electrophoresis and pattern recognition techniques.

    PubMed

    Reid, Raymond G; Durham, David G; Boyle, Susanne P; Low, Ann S; Wangboonskul, Jinda

    2007-12-12

    Opium samples from four different locations and poppy straw from different plant varieties have been assayed using micellar capillary electrophoresis incorporating a sweeping technique. Individual alkaloids (morphine, codeine, papaverine, noscapine, thebaine, oripavine, reticuline and narceine) were quantitatively determined in the different samples by a validated capillary electrophoresis method. Unsupervised pattern recognition of the opium samples and the poppy straw samples using hierarchical cluster analysis (HCA) and principal component analysis (PCA), showed distinct clusters. Supervised pattern recognition using soft independent modelling of class analogy (SIMCA) was performed to show individual groupings and allow unknown samples to be classified according to the models built using the CZE assay results.

  14. Differentiation of opium and poppy straw using capillary electrophoresis and pattern recognition techniques.

    PubMed

    Reid, Raymond G; Durham, David G; Boyle, Susanne P; Low, Ann S; Wangboonskul, Jinda

    2007-12-12

    Opium samples from four different locations and poppy straw from different plant varieties have been assayed using micellar capillary electrophoresis incorporating a sweeping technique. Individual alkaloids (morphine, codeine, papaverine, noscapine, thebaine, oripavine, reticuline and narceine) were quantitatively determined in the different samples by a validated capillary electrophoresis method. Unsupervised pattern recognition of the opium samples and the poppy straw samples using hierarchical cluster analysis (HCA) and principal component analysis (PCA), showed distinct clusters. Supervised pattern recognition using soft independent modelling of class analogy (SIMCA) was performed to show individual groupings and allow unknown samples to be classified according to the models built using the CZE assay results. PMID:18022406

  15. "Getting the best sensitivity from on-capillary fluorescence detection in capillary electrophoresis" - A tutorial.

    PubMed

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2016-09-01

    Capillary electrophoresis with Laser-Induced Fluorescence (CE-LIF) detection is being applied to new analytical problems which challenge both the power of CE separation and the sensitivity of LIF detection. On-capillary LIF detection is much more practical than post-capillary detection in a sheath-flow cell. Therefore, commercial CE instruments utilize solely on-capillary CE-LIF detection with a Limit of Detection (LOD) in the nM range, while there are multiple applications of CE-LIF that require pM or lower LODs. This tutorial analyzes all aspects of on-capillary LIF detection in CE in an attempt to identify means for improving LOD of CE-LIF with on-capillary detection. We consider principles of signal enhancement and noise reduction, as well as relevant areas of fluorophore photochemistry and fluorescent microscopy. PMID:27543015

  16. Determination of the specific activities of methionine sulfoxide reductase A and B by capillary electrophoresis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capillary electrophoresis (CE) method for the determination of methionine sulfoxide reductase A and methionine sulfoxide reductase B activities in mouse liver is described. The method is based on detection of the 4-(dimethylamino)azobenzene-4’-sulfonyl derivative of L-methionine (dabsyl Met), the ...

  17. Novel solid phase extraction method for the analysis of 5-nitroimidazoles and metabolites in milk samples by capillary electrophoresis.

    PubMed

    Hernández-Mesa, Maykel; García-Campaña, Ana M; Cruces-Blanco, Carmen

    2014-02-15

    A new sample treatment has been developed for the extraction of 5-nitroimidazole (5-NDZ) drugs in milk samples previous to their determination by micellar electrokinetic chromatography (MEKC). Fat removing and protein precipitation were simultaneously carried out by the addition of trichloroacetic acid (TCA) and subsequent centrifugation. Clean-up and off-line concentration were achieved by a novel solid-phase extraction (SPE) method employing mixed cation exchange (MCX) cartridges, obtaining an off-line concentration factor of 18. Analyses were performed in less than 18 min employing 20mM phosphate buffer (pH 6.5) and 150 mM SDS as background electrolyte (BGE). During the separation procedure a temperature of 20 °C and a voltage of 25 kV (normal mode) were applied. Due to sweeping effects, an on-line concentration was achieved for all the studied compounds and detection limits lower than 1.8 μg L(-1) were obtained. This method has been successfully applied to milk samples of different origins, including raw ewe milk.

  18. A validated method for the determination of nucleotides in infant formulas by capillary electrophoresis coupled to mass spectrometry.

    PubMed

    Rodríguez-Gonzalo, Encarnación; Domínguez-Álvarez, Javier; Mateos-Vivas, María; García-Gómez, Diego; Carabias-Martínez, Rita

    2014-06-01

    In this work CE-ESI-MS is proposed for the identification and simultaneous quantification of several ribonucleotide 5'-monophosphates in infant formula (IF) samples. The target compounds were adenosine 5'-monophosphate, cytidine 5'-monophosphate, guanosine 5'-monophosphate, uridine 5'-monophosphate, and inosine 5'-monophosphate. To our knowledge, the application of CE for the determination of these bioactive compounds in IFs has not yet been described. Optimization of the composition of the electrophoretic separation buffer and -mainly- the injection medium was carried out with a view to obtaining the best sensitivity and separation efficiency for the CE-MS coupling. Different sample treatments were assayed and one based on centrifugal ultrafiltration proved to be the simplest and most compatible with CE separation of the analytes and their ionization by the electrospray source. The whole optimized method (centrifugal ultrafiltration treatment prior to CE-MS) was validated according to the 2002/657/EC decision, obtaining a reliable and robust CE-MS method to determine these compounds in IF samples, with LODs between 0.8 and 1.8 μg/g (S/N = 3) and recoveries in the 90-106% range.

  19. Quantification of sugars in breakfast cereals using capillary electrophoresis.

    PubMed

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

    2015-05-18

    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).

  20. Contactless conductivity detector for microchip capillary electrophoresis

    NASA Technical Reports Server (NTRS)

    Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelinek, Ivan; Feldman, Jason; Lowe, Holger; Hardt, Steffen; Svehla, D. (Principal Investigator)

    2002-01-01

    A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

  1. Microchip Non-Aqueous Capillary Electrophoresis (MicronNACE) Method to Analyze Long-Chain Primary Amines

    NASA Technical Reports Server (NTRS)

    Willis, Peter A.; Mora, Maria; Cable, Morgan L.; Stockton, Amanda M.

    2012-01-01

    A protocol was developed as a first step in analyzing the complex organic aerosols present on Saturn's moon Titan, as well as the analogues of these aerosols (tholins) made on Earth. Labeling of primary amines using Pacific Blue succinimidyl ester is effected in ethanol with 25 mM triethylamine to maintain basic conditions. This reaction is allowed to equilibrate for at least one hour. Separation of the labeled primary amines is performed in ethanol with 1.05 M acetic acid, and 50 mM ammonium acetate in a commercial two-layer glass device with a standard crossmicrochannel measuring 50 microns wide by 20 microns deep. Injection potentials are optimized at 2 kV from the sample (negative) to the waste well (positive), with slight bias applied to the other two wells ( 0.4 and 0.8 V) to pinch the injection plug for the 30-s injection. Separation is performed at a potential of 5 kV along the channel, which has an effective separation distance of 7 cm. The use of ethanol in this method means that long-chain primary amines can be dissolved. Due to the low pH of the separation buffer, electro-osmotic flow (EOF) is minimized to allow for separation of both short-chain and longchain amines. As the freezing point of ethanol is much lower than water, this protocol can perform separations at temperatures lower than 0 C, which would not be possible in aqueous phase. This is of particular importance when considering in situ sampling of Titan aerosols, where unnecessary heating of the sample (even to room temperature) would lead to decomposition or unpredictable side reactions, which would make it difficult to characterize the sample appropriately.

  2. A capillary electrophoresis assay for recombinant Bacillus subtilis protoporphyrinogen oxidase.

    PubMed

    Tan, Ying; Sun, Lu; Xi, Zhen; Yang, Guang-Fu; Jiang, Dong-Qing; Yan, Xiu-Ping; Yang, Xing; Li, He-Yang

    2008-12-15

    Protoporphyrinogen oxidase (PPO) is a flavin adenine dinucleotide (FAD)-containing enzyme in the tetrapyrrole biosynthetic pathway that leads to the formation of both heme and chlorophylls, which has been identified as one of the most important action targets of commercial herbicides. The literature reports gave different PPO-catalytic kinetic parameters for the substrate protoporphyrinogen IX (K(m) of 0.1 to 10.4 miocroM) with different sources of PPO using fluorescent or HPLC methods. Herein we assayed the enzymatic activity of recombinant Bacillus subtilis PPO by using capillary electrophoresis (CE), a method with high separation efficiency, easy automation, and low sample consumption. The Michaelis constant and maximum reaction velocity were determined as 7.0+/-0.6 miocroM and 0.38+/-0.02 miocromol min(-1)miocrog(-1), respectively. The interaction between PPO and acifluorfen, a commercial PPO-inhibiting herbicide, was measured as the inhibition constant 186.9+/-9.3 miocroM EM, Cyrillic. The relationship between cofactor FAD and PPO activity can also be quantitatively studied by this CE method. The CE method used here should also be a convenient, reliable method for PPO study.

  3. Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

    PubMed

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

    2014-08-29

    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.

  4. Bioanalytical Application of Amino Acid Detection by Capillary Electrophoresis.

    PubMed

    Fico, Daniela; Pennetta, Antonio; De Benedetto, Giuseppe E

    2016-01-01

    This chapter illustrates the usefulness of capillary electrophoresis (CE) for the analysis of amino acids, and both normal and chiral separations are covered. In order to provide a general description of the main results and challenges in the biomedical field, some relevant applications and reviews on CE of amino acids are tabulated. Furthermore, some detailed experimental procedures are shown, regarding the CE analysis of amino acids in body fluids, in microdialysate, and released upon hydrolysis of proteins. In particular, the protocols will deal with the following compounds: (1) underivatized aminoacids in blood; (2) γ-Aminobutyric acid, glutamate, and L-Aspartate derivatized with Naphthalene-2,3-dicarboxaldehyde; (3) hydrolysate from bovine serum albumine derivatized with phenylisothiocyanate. By examining these applications on real matrices, the capillary electrophoresis efficiency as tool for Amino Acid analysis can be ascertained. PMID:27645741

  5. Microchip Capillary Electrophoresis with Electrochemical Detection for Monitoring Environmental Pollutants

    SciTech Connect

    Chen, Gang; Lin, Yuehe; Wang, Joseph

    2006-01-15

    This invited paper reviews recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered include the fabrication of microfluidic chips, sample pretreatments, ECD, typical applications of microchip CE with ECD in environmental analysis, and future prospects. It is expected that microchip CE-ECD will become a powerful tool in the environmental field and will lead to the creation of truly portable devices.

  6. Development of a capillary electrophoresis method for the analysis in alkaline media as polyoxoanions of two strategic metals: Niobium and tantalum.

    PubMed

    Deblonde, Gauthier J-P; Chagnes, Alexandre; Cote, Gérard; Vial, Jérôme; Rivals, Isabelle; Delaunay, Nathalie

    2016-03-11

    Tantalum (Ta) and niobium (Nb) are two strategic metals essential to several key sectors, like the aerospace, gas and oil, nuclear and electronic industries, but their separation is really difficult due to their almost identical chemical properties. Whereas they are currently produced by hydrometallurgical processes using fluoride-based solutions, efforts are being made to develop cleaner processes by replacing the fluoride media by alkaline ones. However, methods to analyze Nb and Ta simultaneously in alkaline samples are lacking. In this work, we developed a capillary zone electrophoresis (CE) method able to separate and quantify Nb and Ta directly in alkaline media. This method takes advantage of the hexaniobate and hexatantalate ions which are naturally formed at pH>9 and absorb in the UV domain. First, the detection conditions, the background electrolyte (BGE) pH, the nature of the BGE co-ion and the internal standard (IS) were optimized by a systematic approach. As the BGE counter-ion nature modified the speciation of both ions, sodium- and lithium-based BGE were tested. For each alkaline cation, the BGE ionic strength and separation temperature were optimized using experimental designs. Since changes in the migration order of IS, Nb and Ta were observed within the experimental domain, the resolution was not a monotonic function of ionic strength and separation temperature. This forced us to develop an original data treatment for the prediction of the optimum separation conditions. Depending on the consideration of either peak widths or peak symmetries, with or without additional robustness constraints, four optima were predicted for each tested alkaline cation. The eight predicted optima were tested experimentally and the best experimental optimum was selected considering analysis time, resolution and robustness. The best separation was obtained at 31.0°C and in a BGE containing 10mM LiOH and 35mM LiCH3COO.The separation voltage was finally optimized

  7. Development of a capillary electrophoresis method for the analysis in alkaline media as polyoxoanions of two strategic metals: Niobium and tantalum.

    PubMed

    Deblonde, Gauthier J-P; Chagnes, Alexandre; Cote, Gérard; Vial, Jérôme; Rivals, Isabelle; Delaunay, Nathalie

    2016-03-11

    Tantalum (Ta) and niobium (Nb) are two strategic metals essential to several key sectors, like the aerospace, gas and oil, nuclear and electronic industries, but their separation is really difficult due to their almost identical chemical properties. Whereas they are currently produced by hydrometallurgical processes using fluoride-based solutions, efforts are being made to develop cleaner processes by replacing the fluoride media by alkaline ones. However, methods to analyze Nb and Ta simultaneously in alkaline samples are lacking. In this work, we developed a capillary zone electrophoresis (CE) method able to separate and quantify Nb and Ta directly in alkaline media. This method takes advantage of the hexaniobate and hexatantalate ions which are naturally formed at pH>9 and absorb in the UV domain. First, the detection conditions, the background electrolyte (BGE) pH, the nature of the BGE co-ion and the internal standard (IS) were optimized by a systematic approach. As the BGE counter-ion nature modified the speciation of both ions, sodium- and lithium-based BGE were tested. For each alkaline cation, the BGE ionic strength and separation temperature were optimized using experimental designs. Since changes in the migration order of IS, Nb and Ta were observed within the experimental domain, the resolution was not a monotonic function of ionic strength and separation temperature. This forced us to develop an original data treatment for the prediction of the optimum separation conditions. Depending on the consideration of either peak widths or peak symmetries, with or without additional robustness constraints, four optima were predicted for each tested alkaline cation. The eight predicted optima were tested experimentally and the best experimental optimum was selected considering analysis time, resolution and robustness. The best separation was obtained at 31.0°C and in a BGE containing 10mM LiOH and 35mM LiCH3COO.The separation voltage was finally optimized

  8. Development of a hollow fibre liquid-phase micro extraction method coupled with capillary electrophoresis/mass spectrometry for determining nitrophenolic compounds from atmospheric particles

    NASA Astrophysics Data System (ADS)

    Teich, Monique; van Pinxteren, Dominik; Herrmann, Hartmut

    2014-05-01

    Nitrophenolic compounds present in the atmosphere gained a lot of attention as they are known for their negative effect on human health as well as for their phytotoxity being a cause for forest decline. Moreover, nitrophenols have the ability to absorb light in the range of near ultra violet to visible light, thus they are also contributing to the so-called brown carbon. Most of the available methods for determining nitrophenols in particulate matter are using organic solvents for extraction. Those methods are not applicable if one wants to focus only on the water-soluble fraction. Therefore, a method using a three-phase hollow fibre liquid-phase micro extraction (HF-LPME) was developed to enrich nine nitrophenolic compounds (2-Nitrophenol, 3-Nitrophenol, 4-Nitrophenol, 2-Methyl-4-nitrophenol, 3-Methyl-4-nitrophenol, 4-Nitrocatechol, 2,6-Dimethyl-4-nitrophenol, 2,4-Dinitrophenol, 3,4-Dinitrophenol) from aqueous extracts of atmospheric particles. Analysis was performed by capillary electrophoresis coupled with electrospray ionisation mass spectrometry (CE-ESI-MS). The background electrolyte composition was optimised to a 20 mM ammonium acetate buffer at pH 9.7 containing 15% methanol (v/v). Persistent peak tailing during electrophoretic separation was observed for 4-Nitrocatechol. Flushing the capillary with Ethylenediaminetetraacetic acid (EDTA) prior sample injection strongly improved the peak shape. Four extraction parameters (composition of organic liquid membrane, pH of acceptor phase, salting out effect, extraction time) and their effect on the analyte recoveries were examined. The HF-LPME consisted of 1.8 mL sample solution kept at pH 2 as donor phase and 15 µl 100 mM aqueous ammonia solution as acceptor phase inserted into a hollow fibre. Dihexyl ether was used to form a supported liquid membrane inside the pores of the hollow fibre. As a result low detection limits in the range of nmol L-1 were achieved and the developed method was found to be competitive

  9. [Determination of glyoxalate and oxalate by capillary zone electrophoresis].

    PubMed

    Guan, Jin; Wang, Huize; Ren, Liyan; Niu, Qiuling

    2012-01-01

    A method for the simultaneous determination of glyoxalate and oxalate by capillary zone electrophoresis (CZE) was developed. The influences of type, concentration and pH of the running buffer, and the applied voltage on separation were investigated. Glyoxalate and oxalate were separated within 11 min under the conditions of 20 mmol/L borax-5.5 mmol/L potassium hydrogen phthalate (pH 9.0), applied voltage of 20 kV, and detected wavelength of 212 nm. The calibration curves of glyoxalate and oxalate showed good linearity in the ranges of 0.8 -20 g/L and 1.2-20 g/L, respectively. The correlation coefficients were 0.999 3 and 0.997 5, respectively. The limits of detection for glyoxalate and oxalate were 0.2 and 0.4 g/L (S/N = 3), respectively. The average recoveries at three spiked levels were 98.3%-102.5% with acceptable relative standard deviations of 0.35%-0.61%. This method is simple, low cost and high performance. The method was successfully used for the determination of glyoxalate and oxalate in real samples, and the assay results were satisfactory. PMID:22667103

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

    PubMed Central

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

    2007-01-01

    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 been analyzed by high pH anion exchange chromatography with pulsed amperometric detection, and, in our laboratory, by CE with detection at 205 nm. The novel method described herein uses a running buffer of aqueous 200 mM NaH2PO4 at pH 7.05 containing 100 mM SDS made 45% (v/v) with methanol to baseline resolve five oligosaccharides, and separate all 12. This allows automated simultaneous quantification of the 12 major sialyloligosaccharides of human milk in a single 35-minute 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. PMID:17761135

  11. SIMULTANEOUS DTERMINATION OF CHROMATE AND AROMATIC HYDROCARBONS IN ENVIRONMENTAL SAMPLES BY CAPILLARY ELECTROPHORESIS

    EPA Science Inventory

    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...

  12. Determination of counter-ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis.

    PubMed

    Mrozik, Wojciech; Markowska, Aleksandra; Guzik, Lukasz; Kraska, Bartłomiej; Kamysz, Wojciech

    2012-03-01

    The utility of three various analytical techniques [ion chromatography (IC), capillary electrophoresis (CE) and isotachophoresis (ITP)] was tested in the determination of counter-ions in synthetic peptides. The analyzed ions were acetates, trifluoroacetates and chlorides. IC provided the best results; CE, except limit of detection and limit of quantification, exhibited the comparable results. ITP was classified as the less useful because of the problem with the determination of the chloride ions. Nevertheless, all the three techniques were able to analyze trifluoroacetates and acetates ions with satisfactory results. Except analytical methods, three procedures using hydrochloric acid (HCl) (at two different concentrations) and acetic acid as sample solvents processed by lyophilization were tested. It has been found that the lyophilization not only by HCl but also by acetic acid is a simple and cheap procedure for removal of toxic trifluoroacetic counter-ions from peptides on satisfactory levels.

  13. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, Richard P.; Udseth, Harold R.; Olivares, Jose A.

    1989-01-01

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

  14. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, Richard D.; Udseth, Harold R.; Olivares, Jose A.

    1994-10-18

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

  15. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, R.D.; Udseth, H.R.; Olivares, J.A.

    1994-10-18

    A system and method for analyzing molecular constituents of a composition sample include: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g.,{+-}2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

  16. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, R.P.; Udseth, H.R.; Olivares, J.A.

    1989-12-05

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., [+-]2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

  17. Capillary electrophoresis separation of the desamino degradation products of oxytocin

    PubMed Central

    Creamer, Jessica S.; Krauss, Shannon T.; Lunte, Susan M.

    2014-01-01

    Oxytocin is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid capillary electrophoresis method using UV detection at 214 nm for the determination of the deamidation products of oxytocin. Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from oxytocin, 11 mM sulfobutyl ether β-cyclodextrin and 10% v/v MeOH were added to a background electrolyte of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5-100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat-stress degradation of oxytocin at 70°C, where all seven desamino species were observed over a 96 h period. PMID:24166826

  18. Detection of salmonellae in chicken feces by a combination of tetrathionate broth enrichment, capillary PCR, and capillary gel electrophoresis.

    PubMed

    Carli, K T; Unal, C B; Caner, V; Eyigor, A

    2001-05-01

    This report describes a rapid detection procedure for salmonellae from chicken feces by the combination of tetrathionate primary enrichment (preenrichment [PE])-bacterial lysis-capillary PCR and capillary gel electrophoresis. Pure Salmonella enterica serovar Enteritidis 64K was reisolated and detected by capillary PCR after buffered peptone water and nutrient broth, tetrathionate broth base Hajna (TTBH), and tetrathionate broth (TTB) preenrichments. When the same culture was mixed with intestinal homogenate, bacteriological reisolation and capillary PCR detection was achieved only by TTBH and TTB preenrichments. Capillary gel electrophoresis revealed that a Salmonella genus-specific 281-bp PCR product was detected when Salmonella strains but not non-Salmonella strains were tested. The detection limit of capillary PCR with whole-cell DNA extracted from pure Salmonella enterica serovars Enteritidis 64K, Typhimurium LT2-CIP60-62, and Gallinarum 64K was 3, 3, and 9 CFU ml(-1), respectively. The detection limit of capillary PCR from whole-cell DNA extracted from intestinal homogenate artificially contaminated with the same three strains was 3, 3, and 7 CFU ml(-1), respectively. We compared the results of the capillary PCR and bacteriological examination from the natural samples. Thirty-five of 53 naturally contaminated samples produced a specific PCR product. In 9 of the 35 PCR-positive samples, Salmonella could not be detected bacteriologically either by PE or a primary and delayed secondary enrichment (DSE) combination. In the 18 PCR-negative samples, 4 samples were found to harbor Salmonella by both PE and DSE and 14 samples were positive after DSE. Fifty-three additional intestinal homogenate samples, which were negative by their PE and DSE in bacteriological examination, were found to be also negative by their PCRs. The total time required to detect Salmonella with the capillary PCR method we used was approximately 20 h. If samples are from clinically diseased

  19. [Applications of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia].

    PubMed

    Leng, Xin; Li, Ling-Di; Li, Jin-Lan; Huang, Xiao-Jun; Ruan, Guo-Rui

    2014-02-01

    The purpose of the present study was to compare the reliability of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia. The FLT3-ITD mutation in the genomic DNA samples from 214 untreated AML patients were separately detected by PCR-microchip electrophoresis and PCR-capillary electrophoresis, then the DNA direct sequencing analysis was carried out. The results from PCR-microchip electrophoresis showed that there were 151 FLT3-ITD mutation negative, 58 FLT3-ITD mutation positive (58/214, 27.1%) and 5 FLT3-ITD mutation doubtful positive (5/214, 2.3%), while the outcomes from PCR-capillary electrophoresis displayed that there were 147 FLT3-ITD mutation negative and 67 FLT3-ITD mutation positive (67/214, 31.3%) without doubtful positive. In the 67 FLT3-ITD mutation positive samples detected by using PCR-capillary electrophoresis, 4 samples were detected as the negative while 5 samples were measured as the doubtful positive by using PCR-microchip electrophoresis. The followed sequencing analysis demonstrated that the above 9 samples were all FLT3-ITD mutation positive, indicating that PCR-capillary electrophoresis was more accurate and sensitive in screening the FLT3-ITD mutation, although statistic analysis showed that there were no significant differences in the detected results between PCR-microchip electrophoresis and PCR-capillary electrophoresis groups (Pearson Chi-squared Test, P > 0.05). It is concluded that both PCR-microchip electrophoresis and PCR-capillary electrophoresis were convenient and fast for screening FLT3-ITD mutation, but the accuracy of PCR-microchip electrophoresis awaits further improvement.

  20. Design and performance of a sheathless capillary electrophoresis/mass spectrometry interface by combining fused-silica capillaries with gold-coated nanoelectrospray tips.

    PubMed

    Kele, Zoltán; Ferenc, Györgyi; Klement, Eva; Tóth, Gábor K; Janáky, Tamás

    2005-01-01

    A simple sheathless capillary electrophoresis (CE)/mass spectrometry (MS) interface was constructed by combining widely used nanospray needles with fused-silica capillaries and it was successfully applied for the separation of peptides. The end of the CE capillary was pulled to a taper, etched and then fitted into the metal-coated nanospray borosilicate capillary. The nanospray needle can be used for several CE runs, but it can be easily and rapidly changed in the case of accidental breakage or evaporation of the coating. A fast capillary electrochromatographic method was also developed for MS analysis of peptides containing numerous basic amino acids. PMID:15724233

  1. Stacking in a continuous sample flow interface in capillary electrophoresis.

    PubMed

    Gstoettenmayr, Daniel; Quirino, Joselito; Ivory, Cornelius F; Breadmore, Michael

    2015-08-21

    Using a tee connector in a commercial capillary electrophoresis instrument, the effect of field amplified sample injection from both flowing and static sample volumes was investigated. It is shown that under identical conditions (40min electrokinetic injection at 5kV from a sample volume of 295μL) the limit of detection using the continuous sample flow interface is 4 times lower than from a static vial. The relationship between different flow rates and injection voltages on the injected sample amount was also investigated using a 2D axisymmetric simulation (COMSOL 4.3b) and verified experimentally, confirming conditions under which there is near-quantitative injection of the sample target ions. Using electrokinetic injection at 30kV and a flow rate of 558nL/s the same enhancement from an even smaller volume of 184μL could be achieved in 5.5min than could be achieved from 295μL and a 40min injection. This sensitivity enhancement factor corresponded to four orders of magnitude improvement compared to a hydrodynamic injection. This is the first report showing that a continuous sample flow interface combined with stacking methods under conditions approaching quantitative injection from the entire sample volume has the potential to be more sensitive than a static system. PMID:26189205

  2. A Contactless Capacitance Detection System for Microchip Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Wu, Peter

    2008-05-01

    The design, construction and operation of a simple, inexpensive and compact high voltage power supply for use in conjunction with a simple cross, capillary electrophoresis microchip is presented. The detection system utilizes a single high voltage power supply (15 kV), a voltage divider network for obtaining the required voltages for enabling a gated injection valve, and two high voltage relays for switching between the open and closed gate sequences of the injection. The system is used to determine sodium monofluoroacetate (MFA) concentration in diluted fruit juices and tap water. A separation buffer consisting of 20 mM citric acid and histidine at pH 3.5 enabled the detection of the anion in diluted apple juice, cranberry juice, and orange juice without lengthy sample pretreatments. Limit of detection in diluted juices and tap water were determined to be 125, 167, 138, and 173 mg/L for tap water, apple juice, cranberry juice, and orange juice, respectively, based upon an S/N of 3:1. The total analysis time for detecting the MFA anion in fruit juices was less than 5 min, which represents a considerable reduction in analysis time compared to other analytical methods currently used in food analysis.

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

    PubMed Central

    Adler, Heidi; Sirén, Heli

    2014-01-01

    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. PMID:24729915

  4. Quantification of Carbohydrates in Grape Tissues Using Capillary Zone Electrophoresis

    PubMed Central

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

    2016-01-01

    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. PMID:27379118

  5. Quantification of Carbohydrates in Grape Tissues Using Capillary Zone Electrophoresis.

    PubMed

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

    2016-01-01

    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.

  6. Application of cyclodextrins in chiral capillary electrophoresis.

    PubMed

    Rezanka, Pavel; Navrátilová, Klára; Rezanka, Michal; Král, Vladimír; Sýkora, David

    2014-10-01

    CE represents a very powerful separation tool in the area of chiral separations. CD-mediated chiral CE is a continuously flourishing technique within the frame of the electromigration methods. In this review, a brief overview of the synthetic procedures leading to modified CDs is provided first. Next, selected aspects related to the utilization of CDs in chiral CE are discussed specifically in the view of recently published data. Advantages of CDs and basic principles of chiral CE are remained. The topic of the determination of binding constants is touched. Particular attention is paid to the effort aiming at better understanding of the molecular level of the enantiorecognition between CDs and the analyte in the solution. Powerful approaches extensively utilized in this field are NMR, molecular modeling, and computer simulations. Then, a summary of applications of CDs in the CE enantioseparations is given, covering years 2008-2013. Finally, the general trend of modified CDs use in separation science is statistically evaluated.

  7. Droplet microfluidics for postcolumn reactions in capillary electrophoresis.

    PubMed

    Abdul Keyon, Aemi S; Guijt, Rosanne M; Bolch, Christopher J; Breadmore, Michael C

    2014-12-01

    A postcolumn reaction system based on droplet microfluidics was developed for capillary electrophoresis (CE). Analytes were separated using capillary zone electrophoresis (CZE) and electrophoretically transferred into droplets. The use of a micro cross for positioning a salt bridge-electrode opposite the separation capillary outlet is the key element for maintaining the electrical connection during electrophoretic separation. As the first of its kind, positioning the droplets in the electric field eliminated the need for electroosmotic flow (EOF) or hydrodynamic flow for droplet compartmentalization. Depending on the total flow rate of both aqueous and oil phases, droplets of water-in-oil could be formed having frequencies between 0.7 and 3.7 Hz with a size of approximately 14 nL per droplet. Compartmentalized in the droplets, analytes reacted with reagents already present in the droplets to facilitate detection. The periodate oxidation of paralytic shellfish toxins (PSTs) was demonstrated, overcoming the limitation of precolumn oxidation, which results in multiple and sometimes identical oxidation products formed from the different PSTs. Compartmentalization allows the oxidation products for each peak to be contained and to contribute to a single fluorescence signal, preserving the selectivity of CZE separation while gaining the sensitivity of fluorescence detection.

  8. Phaseolin seed variability in common bean (Phaseolus vulgaris L.) by capillary gel electrophoresis.

    PubMed

    Salmanowicz, B P

    2001-01-01

    Phaseolin, the major seed storage protein of Phaseolus vulgaris from forty-four wild and cultivated accessions, was studied using sodium dodecyl sulphate-capillary gel electrophoresis (SDS-CGE). In total, eleven phaseolin profiles, revealing polypeptide subunit variation in the range from 45.6 kDa to 54.4 kDa, were recorded. The number of polypeptide subunits recorded in particular profiles varied from 3 to 6; in total, eight phaseolin subunits were distinguished in the examined material. Ferguson plot analysis was used to correct non-ideal behaviour of phaseolin polypeptide subunits in capillary gel electrophoresis in the presence of SDS. The obtained results are compared to electrophoretic data received by slab polyacrylamide gel electrophoresis. The SDS-CGE method appears to provide a powerful tool for disclosure of phaseolin subunit variability.

  9. [In situ photopolymerization of polyacrylamide-based preconcentrator on a microfluidic chip for capillary electrophoresis].

    PubMed

    Yamamoto, Sachio

    2012-01-01

    Microchip electrophoresis is widely used for microfluidics and has been studied extensively over the past decade. Translation of capillary electrophoresis methods from traditional capillary systems to a microchip platform provides rapid separation and easy quantitation of sample components. However, most microfluidic systems suffer from critical scaling problems. One promising solution to this problem is online sample preconcentration of all analytes in a sample reservoir before the separation channel. Herein, the following three techniques for online preconcentration during microchip electrophoresis are proposed: (1) in situ fabrication of an ionic polyacrylamide-based preconcentrator on a simple poly(methyl methacrylate) microfluidic chip for perm-selective preconcentration and capillary electrophoretic separation of anionic compounds, (2) simultaneous concentration enrichment and electrophoretic separation of weak acids on a microchip using an in situ photopolymerized carboxylate-type polyacrylamide gels as the perm-selective preconcentrator, and (3) microchip electrophoresis of oligosaccharides using lectin-immobilized preconcentrator gels fabricated by in situ photopolymerization. These techniques are expected to be powerful tools for clinical and pharmaceutical studies with on-line preconcentration during microchip electrophoresis.

  10. [In situ photopolymerization of polyacrylamide-based preconcentrator on a microfluidic chip for capillary electrophoresis].

    PubMed

    Yamamoto, Sachio

    2012-01-01

    Microchip electrophoresis is widely used for microfluidics and has been studied extensively over the past decade. Translation of capillary electrophoresis methods from traditional capillary systems to a microchip platform provides rapid separation and easy quantitation of sample components. However, most microfluidic systems suffer from critical scaling problems. One promising solution to this problem is online sample preconcentration of all analytes in a sample reservoir before the separation channel. Herein, the following three techniques for online preconcentration during microchip electrophoresis are proposed: (1) in situ fabrication of an ionic polyacrylamide-based preconcentrator on a simple poly(methyl methacrylate) microfluidic chip for perm-selective preconcentration and capillary electrophoretic separation of anionic compounds, (2) simultaneous concentration enrichment and electrophoretic separation of weak acids on a microchip using an in situ photopolymerized carboxylate-type polyacrylamide gels as the perm-selective preconcentrator, and (3) microchip electrophoresis of oligosaccharides using lectin-immobilized preconcentrator gels fabricated by in situ photopolymerization. These techniques are expected to be powerful tools for clinical and pharmaceutical studies with on-line preconcentration during microchip electrophoresis. PMID:23023420

  11. Semisynthetic chondroitins as chiral buffer additives in capillary electrophoresis.

    PubMed

    Gotti, R; Cavrini, V; Andrisano, V; Mascellani, G

    1999-06-11

    Chemically oversulfated galactosaminoglycans with potential as therapeutic agents (inhibitors of human leukocyte elastase) were tested as chiral selectors in capillary electrophoresis of basic racemates. The high anionic character of these compounds provides them with anodic mobility in acidic buffer; using uncoated capillaries, the enantioresolution of racemic basic drugs was obtained at pH 2.5. Dimethindene, chloroquine and chlorpheniramine were enantioresolved applying negative voltage (-15 kV) while the other analytes (propranolol, pindolol, tetrahydrozoline and cloperastine) exhibited catodic migration. The addition of organic solvents to the running buffer was evaluated in order to increase the resolution; methanol provides the best results and in general, baseline separation of the analytes was reached. The studied oversulfated mucopolysaccharide, shows the same ionic character of heparin but presents different stereochemistry and sites of sulfation. A comparison with heparin, used in the same acidic conditions, may underline the role of ionic, spatial and steric features of glycosaminoglycans in the enantiorecognition.

  12. Theoretical and experimental separation dynamics in capillary zone electrophoresis

    NASA Technical Reports Server (NTRS)

    Thormann, Wolfgang; Michaud, Jon-Pierre; Mosher, Richard A.

    1986-01-01

    The mathematical model of Bier et al. (1983) is used in a computer aided analysis of the conditions in capillary zone electrophoresis (ZE) under which sample zones migrate noninteractively with the carrier electrolyte. The monitoring of sample zones with a capillary analyzer that features both on-line conductivity and UV detection at the end of the separation trough is discussed. Data from a ZE analysis of a 5-component mixture are presented, and it is noted that all five components can be monitored via their conductivity change if enough sample is present. It is suggested from the results that the concentration ratio of background buffer to sample should be a minimum of 100:1 to effectively apply the plate concept to ZE.

  13. Fingerprint analysis of Flos Carthami by capillary electrophoresis.

    PubMed

    Sun, Yi; Guo, Tao; Sui, Yin; Li, Famei

    2003-07-25

    Capillary electrophoresis (CE) was employed in fingerprint analysis of Flos Carthami. A standardized procedure was used to develop the CE fingerprint. An electrophoretic profile of genuine Flos Carthami from Fengqiu, He'nan, China, was first established as the characteristic fingerprint. This profile was then used to identify and assess the consistency of the herb. A study with a limited number of samples from nine sources showed a fair consistency in their CE fingerprints with that of the genuine sample. Flos Carthami was well distinguished from Stigma Croci, a possible substitute in traditional Chinese medicine, and Flos Hemerocallis, a commercial adulterant, by comparing the fingerprints of each herb. PMID:12860022

  14. Capillary electrophoresis-electrochemical detection microchip device and supporting circuits

    DOEpatents

    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.

    2008-03-18

    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.

  15. Determination of dissociation constants of flavonoids by capillary electrophoresis.

    PubMed

    Herrero-Martínez, José M; Sanmartin, Meritxell; Rosés, Martí; Bosch, Elisabeth; Ràfols, Clara

    2005-05-01

    Ionization constants of some flavanols (catechin and epicatechin) and flavonols (kaempherol, fisetin, morin, and quercetin) are determined by capillary zone electrophoresis (CZE). This technique allows the determination of pK(a) values until about 12. The pK(a) values obtained are compared with those calculated by the SPARC computational program. This program predicts the microscopic and macroscopic pK(a) values and the order of deprotonation of the different -OH groups. While for catechin and epicatechin the first ionizable OH group occurs in ring 1 and the second ionizable group in ring 2, in flavonols the first deprotonation occurs in ring 2 and the second in ring 1.

  16. Monitoring environmental pollutants by microchip capillary electrophoresis with electrochemical detection

    SciTech Connect

    Chen, Gang; Lin, Yuehe; Wang, Joseph

    2006-01-15

    This is a review article. During the past decade, significant progress in the development of miniaturized microfluidic systems has Occurred due to the numerous advantages of microchip analysis. This review focuses on recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered include the fabrication of microfluidic chips, ECD, typical applications of microchip CE with ECD in environmental analysis, and future prospects. It is expected that microchip CE-ECD will become a powerful tool in the environmental field and will lead to the creation of truly portable devices.

  17. Chiral analysis by capillary electrophoresis using antibiotics as chiral selector.

    PubMed

    Desiderio, C; Fanali, S

    1998-05-20

    The separation of chiral compounds by capillary electrophoresis (CE) is a very interesting field of research in different areas such as pharmaceutical, environmental, agricultural analysis etc. The separation of two enantiomers can be achieved in CE using a chiral environment interacting with the two analytes on forming diastereoisomers with different stability constants and thus different mobilities. A wide number of chiral selectors have been employed in CE and among them glycopeptide antibiotics exhibited excellent enantioselective properties towards a wide number of racemic compounds. Vancomycin, ristocetin A, rifamycins, teicoplanin, kanamycin, streptomycin, fradiomycin, and two vancomycin analogues, added to the background electrolyte (BGE), are the antibiotics studied by CE running the separation in untreated and/or coated fused-silica capillary. Due to adsorption and absorption phenomena, some drawbacks can be expected when using bare fused-silica capillary, e.g., changes of electroosmotic flow (EOF), broaden peaks, reduced efficiency and low sensitivity. Coated capillary and counter current mode can be the solution to overcome the above mentioned problems. This review surveys the separation of enantiomers by CE when macrocyclic antibiotics are used as chiral selector. The enantioselectivity can be easily controlled modifying several parameters such as antibiotic type and concentration, pH, ionic strength and concentration of the background electrolyte, organic modifier etc. The paper also presents a list of the latest chiral separations achieved by CE where antibiotics were used as chiral selector.

  18. Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry.

    PubMed

    Michalke, Bernhard

    2016-01-01

    During the recent years, capillary electrophoresis (CE) has been fully established as a powerful tool in separation sciences as well as in element speciation. This road of success is based on the rapid analysis time, low sample requirements, high separation efficiency, and low operating costs of CE. Inductively coupled plasma mass spectrometry (ICP-MS) is known for superior detection and multielement capability. Consequently, the combination of both instruments is approved for analysis of complex sample types at low element concentrations which require high detection power. Also the diversity of potential applications brings CE-ICP-MS coupling into central focus of element speciation. The key to successful combination of ICP-MS as an (multi-)element selective detector for CE is the availability of a suitable and effective interface.Therefore, this chapter summarizes the most important and basic principles about coupling of capillary electrophoresis to ICP-MS. Specifically, the major requirements for interfacing are described and technical solutions are given. Such solutions include the closing of the electrical circuit from CE at the nebulization, the adoption of flow rates for efficient nebulization, the reduction of a suction flow through the capillary, caused by the nebulizer, and maintaining the high separation resolution from CE across the interface for ICP-MS detection. Additionally, detailed information is presented to determine and quantify the siphoning suction through the CE capillary by the nebulizer. Finally, two applications, namely, the manganese and selenium speciation in cerebrospinal fluid are shown as examples, providing the relevant operational parameter. PMID:27645737

  19. Determination of aggregation thresholds of UV absorbing anionic surfactants by frontal analysis continuous capillary electrophoresis.

    PubMed

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

    2004-06-01

    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.

  20. Determination of sulfametoxazole, sulfadiazine and associated compounds in pharmaceutical preparations by capillary zone electrophoresis.

    PubMed

    Berzas Nevado, J J; Castañeda Peñalvo, G; Guzmán Bernardo, F J

    2001-05-18

    A capillary zone electrophoresis method is presented to separate sulfadiazine, sulfamethoxazole, trimethoprim, bromhexine and guaiacol by using a fused-silica capillary (60.2 cm x 75 microm I.D.). The separation was carried out at 30 kV and 25 degrees C in a 15 mM phosphate buffer adjusted to pH 6.2 as electrolyte. Under these conditions, the run time was 6 min and the limits of quantification were about 1 mg/l for every component. The method was applied to pharmaceutical preparations and the results provided recoveries close to 100%.

  1. Application of capillary electrophoresis to the development and evaluation of aptamer affinity probes

    NASA Astrophysics Data System (ADS)

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

    2007-09-01

    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.

  2. A compact LED-based module for DNA capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Hurth, C.; Lenigk, R.; Zenhausern, F.

    2008-11-01

    A setup consisting of a bifurcated optical fiber made from high-transmission fused-silica cores with relatively high numerical apertures (NA=0.22), high-power cyan light-emitting diodes (LEDs) and Peltier cooling elements controlled by a proportional-integrative-derivative (PID) module is introduced to replace bulky, power- consuming lasers conventionally used in laser induced fluorescence (LIF) microchip capillary electrophoresis (μCE). The output fiber beam size, divergence, power distribution and power stability over time are documented. A modified epifluorescence microscope arrangement is used in conjunction with a compact fixed spectrometer aligned with a cooled charge-coupled device (CCD) camera for added sensitivity. Fluorescent dyes such as fluorescein, 6-carboxyfluorescein (6-FAM) and rhodamine B can be detected in cyclic olefin copolymer (COC) and glass microchannels at submicromolar levels. A single-stranded DNA oligonucleotide (10-mer) labeled with 6-FAM is also detected with reasonable signal-to-noise ratio when electrophoretically migrated at 100 V/cm. The compact LED excitation system presented herein will allow using capillary electrophoresis for DNA detection in compact mobile devices.

  3. Online comprehensive two-dimensional ion chromatography × capillary electrophoresis.

    PubMed

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

    2015-09-01

    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%).

  4. Separation of Trivalent Actinides from Lanthanides Using a Capillary Electrophoresis

    SciTech Connect

    Mori, Tomotaka; Ishii, Yasuo; Hayashi, Kazunori; Suganuma, Hideo; Satoh, Isamu

    2007-07-01

    A separation of {sup 241}Am(III) from {sup 152,154}Eu(III) was carried out using a capillary electrophoresis technique in a mixed solvent (CH{sub 3}OH/H{sub 2}O) system containing thiocyanate ion. First, the formation constants ({beta}{sub n}) between thiocyanate ion and Eu(III) or Am(III) were investigated in the mixed solvent solutions by a back-extraction technique using bis (2-ethylhexyl) hydrogen phosphate-toluene. The mean charges calculated on the basis of the data of {beta}{sub n} for Eu(III) were comparatively higher than those for Am(III). Based on the differences between the mean charges of Eu(III) and Am(III), separations for Am(III)/Eu(III) by means of capillary electrophoresis technique were tried in the (H{sup +}, Na{sup +})(SCN{sup -}, ClO{sub 4}{sup -}) mixed solvent solutions. It was proved that Am(III) was completely separated from Eu(III). (authors)

  5. Microfabricated capillary electrophoresis amino acid chirality analyzer for extraterrestrial exploration

    NASA Technical Reports Server (NTRS)

    Hutt, L. D.; Glavin, D. P.; Bada, J. L.; Mathies, R. A.

    1999-01-01

    Chiral separations of fluorescein isothiocyanate-labeled amino acids have been performed on a microfabricated capillary electrophoresis chip to explore the feasibility of using such devices to analyze for extinct or extant life signs in extraterrestrial environments. The test system consists of a folded electrophoresis channel (19.0 cm long x 150 microns wide x 20 microns deep) that was photolithographically fabricated in a 10-cm-diameter glass wafer sandwich, coupled to a laser-excited confocal fluorescence detection apparatus providing subattomole sensitivity. Using a sodium dodecyl sulfate/gamma-cyclodextrin pH 10.0 carbonate electrophoresis buffer and a separation voltage of 550 V/cm at 10 degrees C, baseline resolution was observed for Val, Ala, Glu, and Asp enantiomers and Gly in only 4 min. Enantiomeric ratios were determined for amino acids extracted from the Murchison meteorite, and these values closely matched values determined by HPLC. These results demonstrate the feasibility of using microfabricated lab-on-a-chip systems to analyze extraterrestrial samples for amino acids.

  6. Capillary Zone Electrophoresis-Mass Spectrometry of Intact Proteins.

    PubMed

    Domínguez-Vega, Elena; Haselberg, Rob; Somsen, Govert W

    2016-01-01

    Capillary electrophoresis (CE) coupled with mass spectrometry (MS) has proven to be a powerful analytical tool for the characterization of intact proteins. It combines the high separation efficiency, short analysis time, and versatility of CE with the mass selectivity and sensitivity offered by MS detection. This chapter focuses on important practical considerations when applying CE-MS for the analysis of intact proteins. Technological aspects with respect to the use of CE-MS interfaces and application of noncovalent capillary coatings preventing protein adsorption are treated. Critical factors for successful protein analysis are discussed and four typical CE-MS systems are described demonstrating the characterization of different types of intact proteins by CE-MS. These methodologies comprise the use of sheath-liquid and sheathless CE-MS interfaces, and various types of noncovalent capillary coatings allowing efficient and reproducible protein separations. The discussion includes the analysis of lysozyme-drug conjugates and the therapeutic proteins human growth hormone, human interferon-β-1a, and human erythropoietin. PMID:27473479

  7. Multidimensional microchip-capillary electrophoresis device for determination of functional proteins in infant milk formula.

    PubMed

    Wu, Ruige; Wang, Zhiping; Fung, Ying Sing

    2015-01-01

    Functional proteins have been found in infant milk formula as supplements, added by an increasing number of manufacturers. Their supplementations are expected to be controlled and monitored. Here, we describe a microchip-integrated CE method for the determination of these low levels of functional proteins in a protein-rich sample matrix. On-chip isoelectric focusing (IEF) is used to separate high-abundance proteins from low-abundance proteins instead of using some complicated time-consuming protein purification process. After that, transient isotachophoresis hyphenated capillary zone electrophoresis (t-ITP-CZE) can preconcentrate, separate, and analyze transferred functional proteins in the embedded capillary under UV detection. PMID:25673487

  8. Multidimensional microchip-capillary electrophoresis device for determination of functional proteins in infant milk formula.

    PubMed

    Wu, Ruige; Wang, Zhiping; Fung, Ying Sing

    2015-01-01

    Functional proteins have been found in infant milk formula as supplements, added by an increasing number of manufacturers. Their supplementations are expected to be controlled and monitored. Here, we describe a microchip-integrated CE method for the determination of these low levels of functional proteins in a protein-rich sample matrix. On-chip isoelectric focusing (IEF) is used to separate high-abundance proteins from low-abundance proteins instead of using some complicated time-consuming protein purification process. After that, transient isotachophoresis hyphenated capillary zone electrophoresis (t-ITP-CZE) can preconcentrate, separate, and analyze transferred functional proteins in the embedded capillary under UV detection.

  9. Simultaneous determination of five flavonoids during the growth of Fructus Sophorae by capillary electrophoresis.

    PubMed

    Li, Yu-Mei

    2013-11-01

    A method of simultaneous determination of five flavonoids during the growth of Fructus Sophorae by β-cyclodextrin (β-CD-) modified capillary zone electrophoresis was developed. The effects of various parameters such as buffer concentration, pH, applied voltage, and β-CD concentrations were investigated. After a series of optimization processes, the determination of five flavonoids in Fructus Sophorae was successfully achieved in 20 mmol/L borax buffer (pH 9.5), 25 kV applied voltage, and 8 mmol/L β-CD. The linearity, detection limits, repeatability, and recovery were satisfactory. Thus, the proposed β-CD-modified capillary zone electrophoresis method was satisfactorily used to analyze Fructus Sophorae samples. The results can be useful for the quality control and medicinal resource development of Fructus Sophorae. PMID:23604719

  10. Determination of acid dissociation constants of warfarin and hydroxywarfarins by capillary electrophoresis.

    PubMed

    Nowak, Paweł; Olechowska, Paulina; Mitoraj, Mariusz; Woźniakiewicz, Michał; Kościelniak, Paweł

    2015-08-10

    In this work the acid dissociation constants--pKa of warfarin and its all important oxidative metabolites have been determined by capillary electrophoresis-based methods. It has resulted in a complete description of two acid-base dissociation equilibria, yet not investigated experimentally for phase I metabolites of warfarin. The capillary electrophoresis (CE) method based on the relation between effective electrophoretic mobilities and pH has proven to be a suitable tool for pKa determination, while the spectrophotometric (CE-DAD) and the internal standard methods (IS-CE), have appeared to be promising alternative approaches. The CE-DAD approach based on the change in absorbance spectra between the acidic and basic forms is a combination between capillary electrophoresis and spectrophotometric titration, and yields very consistent values of pKa1 with CE. The IS-CE, in turn, enables an estimation of pKa1 and pKa2 from only two analytical runs, however, less accurate than CE and CE-DAD. The Debye-Hückel model has been confirmed experimentally as a good predictor of pKa values at various ionic strengths. Therefore, it has been used in determination of thermodynamic pKa1 and pKa2, referring to the zero ionic strength. The results are important from the analytical, pharmacological, and theoretical points of view.

  11. Determination of acid dissociation constants of warfarin and hydroxywarfarins by capillary electrophoresis.

    PubMed

    Nowak, Paweł; Olechowska, Paulina; Mitoraj, Mariusz; Woźniakiewicz, Michał; Kościelniak, Paweł

    2015-08-10

    In this work the acid dissociation constants--pKa of warfarin and its all important oxidative metabolites have been determined by capillary electrophoresis-based methods. It has resulted in a complete description of two acid-base dissociation equilibria, yet not investigated experimentally for phase I metabolites of warfarin. The capillary electrophoresis (CE) method based on the relation between effective electrophoretic mobilities and pH has proven to be a suitable tool for pKa determination, while the spectrophotometric (CE-DAD) and the internal standard methods (IS-CE), have appeared to be promising alternative approaches. The CE-DAD approach based on the change in absorbance spectra between the acidic and basic forms is a combination between capillary electrophoresis and spectrophotometric titration, and yields very consistent values of pKa1 with CE. The IS-CE, in turn, enables an estimation of pKa1 and pKa2 from only two analytical runs, however, less accurate than CE and CE-DAD. The Debye-Hückel model has been confirmed experimentally as a good predictor of pKa values at various ionic strengths. Therefore, it has been used in determination of thermodynamic pKa1 and pKa2, referring to the zero ionic strength. The results are important from the analytical, pharmacological, and theoretical points of view. PMID:25968611

  12. Sensitive detection of malachite green and crystal violet by nonlinear laser wave mixing and capillary electrophoresis.

    PubMed

    Maxwell, Eric J; Tong, William G

    2016-05-01

    An ultrasensitive label-free antibody-free detection method for malachite green and crystal violet is presented using nonlinear laser wave-mixing spectroscopy and capillary zone electrophoresis. Wave-mixing spectroscopy provides a sensitive absorption-based detection method for trace analytes. This is accomplished by forming dynamic gratings within a sample cell, which diffracts light to create a coherent laser-like signal beam with high optical efficiency and high signal-to-noise ratio. A cubic dependence on laser power and square dependence on analyte concentration make wave mixing sensitive enough to detect molecules in their native form without the use of fluorescent labels for signal enhancement. A 532 nm laser and a 635 nm laser were used for malachite green and crystal violet sample excitation. The use of two lasers of different wavelengths allows the method to simultaneously detect both analytes. Selectivity is obtained through the capillary zone electrophoresis separation, which results in characteristic migration times. Measurement in capillary zone electrophoresis resulted in a limit of detection of 6.9 × 10(-10)M (2.5 × 10(-19) mol) for crystal violet and 8.3 × 10(-11)M (3.0 × 10(-20) mol) for malachite green at S/N of 2.

  13. Sensitive detection of malachite green and crystal violet by nonlinear laser wave mixing and capillary electrophoresis.

    PubMed

    Maxwell, Eric J; Tong, William G

    2016-05-01

    An ultrasensitive label-free antibody-free detection method for malachite green and crystal violet is presented using nonlinear laser wave-mixing spectroscopy and capillary zone electrophoresis. Wave-mixing spectroscopy provides a sensitive absorption-based detection method for trace analytes. This is accomplished by forming dynamic gratings within a sample cell, which diffracts light to create a coherent laser-like signal beam with high optical efficiency and high signal-to-noise ratio. A cubic dependence on laser power and square dependence on analyte concentration make wave mixing sensitive enough to detect molecules in their native form without the use of fluorescent labels for signal enhancement. A 532 nm laser and a 635 nm laser were used for malachite green and crystal violet sample excitation. The use of two lasers of different wavelengths allows the method to simultaneously detect both analytes. Selectivity is obtained through the capillary zone electrophoresis separation, which results in characteristic migration times. Measurement in capillary zone electrophoresis resulted in a limit of detection of 6.9 × 10(-10)M (2.5 × 10(-19) mol) for crystal violet and 8.3 × 10(-11)M (3.0 × 10(-20) mol) for malachite green at S/N of 2. PMID:26998858

  14. Ultrafast Capillary Electrophoresis Isolation of DNA Aptamer for the PCR Amplification-Based Small Analyte Sensing

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    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.

  15. Capillary liquid chromatography using laser-based and mass spectrometric detection. [Capillary zone electrophoresis (CZE); micellar electrokinetic capillary kchromatography (MECC)

    SciTech Connect

    Sepaniak, M.J.; Cook, K.D.

    1992-01-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  16. Cyclodextrins in capillary electrophoresis: recent developments and new trends.

    PubMed

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

    2014-08-29

    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.

  17. Microchip capillary electrophoresis based electroanalysis of triazine herbicides.

    PubMed

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

    2015-01-01

    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.

  18. Analysis and applications of nanoparticles in capillary electrophoresis.

    PubMed

    Ban, Eunmi; Yoo, Young Sook; Song, Eun Joo

    2015-08-15

    Nanoparticles (NPs) exhibit unique chemical and physical properties that depend on their size, shape, and environment. NPs are emerging as new tools and techniques in the analytical study of various materials and in the biological and biomedical fields, because of their unique properties. Therefore, the quantitative and qualitative characterization of NPs has gathered increasing interest. Additionally, the NPs are being used in rapidly developing techniques to provide highly sensitive and specific analysis of various materials. Capillary electrophoresis (CE) has been demonstrated as a useful analytical tool for the characterization of NPs and for the evaluation of biological and biomedical studies using NPs because of its simple sample preparation and efficient resolution of a diverse size range of compounds. This paper gives a short overview of the analysis and applications of NPs in CE systems, with an emphasis on biological and biomedical studies. PMID:25966374

  19. Recent developments in electrochemical detection for microchip capillary electrophoresis.

    PubMed

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

    2004-11-01

    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.

  20. Separation of enantiomers by capillary electrophoresis using pentosan polysulfate.

    PubMed

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

    1999-01-01

    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.

  1. Recent advances in affinity capillary electrophoresis for binding studies.

    PubMed

    Albishri, Hassan M; El Deeb, Sami; AlGarabli, Noura; AlAstal, Raghda; Alhazmi, Hassan A; Nachbar, Markus; El-Hady, Deia Abd; Wätzig, Hermann

    2014-01-01

    The present review covers recent advances and important applications of affinity capillary electrophoresis (ACE). It provides an overview about various ACE types, including ACE-MS, the multiple injection mode, the use of microchips and field-amplified sample injection-ACE. The most common scenarios of the studied affinity interactions are protein-drug, protein-metal ion, protein-protein, protein-DNA, protein-carbohydrate, carbohydrate-drug, peptide-peptide, DNA-drug and antigen-antibody. Approaches for the improvements of ACE in term of precision, rinsing protocols and sensitivity are discussed. The combined use of computer simulation programs to support data evaluation is presented. In conclusion, the performance of ACE is compared with other techniques such as equilibrium dialysis, parallel artificial membrane permeability assay, high-performance affinity chromatography as well as surface plasmon resonance, ultraviolet, circular dichroism, nuclear magnetic resonance, Fourier transform infrared, fluorescence, MS and isothermal titration calorimetry. PMID:25534793

  2. Analysis of protamine peptides in insulin pharmaceutical formulations by capillary electrophoresis.

    PubMed

    Lamalle, Caroline; Servais, Anne-Catherine; Demelenne, Alice; Crommen, Jacques; Fillet, Marianne

    2016-03-01

    Protamines are a group of highly basic peptides that are sometimes added to insulin formulations to prolong the pharmacological action. In this study, different methods were investigated to identify protamine in insulin formulations. Capillary electrophoresis in aqueous and non-aqueous media was tested to separate these peptides with very close amino acid sequences. Different buffers (phosphate or formate, both acidified) and various additives (principally negatively charged and neutral surfactants) were investigated to optimize peptide separation. Finally, a micellar electrokinetic capillary chromatography method using a capillary of 120 cm effective length and an aqueous background electrolyte made up of 100 mM phosphate buffer (pH 2) and 50 mM Thesit® gave the best results, providing the separation of the four major protamine peptides within 25 min. PMID:26829340

  3. Direct assay of glutathione peroxidase activity using high-performance capillary electrophoresis.

    PubMed

    Pascual, P; Martinez-Lara, E; Bárcena, J A; López-Barea, J; Toribio, F

    1992-10-01

    A fast, sensitive and direct method has been developed for the determination of glutathione peroxidase activity (both selenium- and non-selenium-dependent) in cell-free preparations. The assay is based on the separation and quantitation of reduced and oxidized glutathione by capillary electrophoresis. The electrophoretic separation buffer was 100 mM sodium tetraborate (pH 8.2) containing 100 mM sodium dodecylsulphate. A micellar electrokinetic mechanism took place under these conditions, and a total mass recovery was observed for both peptides. The reproducibility of migration times was excellent (less than 3% variability). A linear detector response range was observed in the range 5-50 U/ml, and both the reproducibility and accuracy were satisfied. Samples out of this linear range could be analysed by either increasing the reaction time or diluting the enzyme preparation. The results obtained with the new direct capillary electrophoresis assay were compared with those derived from a reversed phase high-performance liquid chromatographic and spectrophotometric coupled assay. A very good agreement was found between the two direct assay methods in all samples. Capillary electrophoresis is a versatile technique that allows the automation of the glutathione peroxidase assay in a reproducible manner and within a relatively short time with sufficient accuracy and precision. PMID:1430007

  4. Amphiphilic silica nanoparticles as pseudostationary phase for capillary electrophoresis separation.

    PubMed

    Li, Hui; Ding, Guo-Sheng; Chen, Jie; Tang, An-Na

    2010-11-19

    Amphiphilic silica nanoparticles surface-functionalized by 3-aminopropyltriethoxysilane (APTES) and octyltriethoxylsilane (OTES) were successfully prepared and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR) and thermogravimetry (TG) techniques. The potential use of these bifunctionalized nanoparticles as pseudostationary phases (PSPs) in capillary electrophoresis (CE) for the separation of charged and neutral compounds was evaluated in terms of their suitability. As expected, fast separation of representative aromatic acids was fulfilled with high separation efficiency, because they migrate in the same direction with the electroosmotic flow (EOF) under optimum experimental conditions. Using a buffer solution of 30mmol/L phosphate (pH 3.0) in the presence of 0.5mg/mL of the synthesized bifunctionalized nanoparticles, the investigated basic compounds were baseline-resolved with symmetrical peaks. Due to the existence of amino groups on the surface of nanoparticles, "silanol effect" that occurs between positively charged basic analytes and the silanols on the inner surface of capillary was greatly suppressed. Furthermore, the separation systems also exhibited reversed-phase (RP) behavior when neutral analytes were tested. PMID:20961550

  5. Determination of acidity constants of enolisable compounds by capillary electrophoresis.

    PubMed

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

    2004-10-01

    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.

  6. Determination of acid dissociation constant of 20 coumarin derivatives by capillary electrophoresis using the amine capillary and two different methodologies.

    PubMed

    Nowak, Paweł Mateusz; Woźniakiewicz, Michał; Piwowarska, Monika; Kościelniak, Paweł

    2016-05-13

    In this work capillary electrophoresis has been used to determine acid dissociation constant of 20 structurally diverse coumarin derivatives. For a majority of compounds pKa value has been determined for the first time. The obtained values vary between 4.16-9.10pH unit, pointing to the interesting structure-acidity relationships. The amine permanently coated capillary has been applied for that purpose, because it has turned out to be more effective in pKa determination than the bare silica and other coated capillaries, ensuring good precision and shorter migration times. A traditional methodology relying on measurements in a broad pH range and fitting of a sigmoidal function has been compared to an alternative simplified approach, reported for the first time, where only two electrophoretic mobility values suffice for pKa estimation. The first value corresponds to the partially ionized form and it is measured experimentally, while the second one to the totally ionized form - it is measured experimentally (two-values method) or estimated directly from molecular mass (one-value method). We show that despite a limited measurements number, the alternative approach may be consistent with the traditional methodology, yielding the relatively low pKa deviation. Its reliability has also been confirmed by the analytical predictions, comprising resolution, migration order, migration times and peaks overlapping. Therefore, combination of the amine capillary with the simplified calculation method is an attractive tool for fast and reliable pKa estimation.

  7. Protein Cross-Linking Capillary Electrophoresis for Protein-Protein Interaction Analysis.

    PubMed

    Ouimet, Claire M; Shao, Hao; Rauch, Jennifer N; Dawod, Mohamed; Nordhues, Bryce; Dickey, Chad A; Gestwicki, Jason E; Kennedy, Robert T

    2016-08-16

    Capillary electrophoresis (CE) has been identified as a useful platform for detecting, quantifying, and screening for modulators of protein-protein interactions (PPIs). In this method, one protein binding partner is labeled with a fluorophore, the protein binding partners are mixed, and then, the complex is separated from free protein to allow direct determination of bound to free ratios. Although it possesses many advantages for PPI studies, the method is limited by the need to have separation conditions that both prevent protein adsorption to capillary and maintain protein interactions during the separation. In this work, we use protein cross-linking capillary electrophoresis (PXCE) to overcome this limitation. In PXCE, the proteins are cross-linked under binding conditions and then separated. This approach eliminates the need to maintain noncovalent interactions during electrophoresis and facilitates method development. We report PXCE methods for an antibody-antigen interaction and heterodimer and homodimer heat shock protein complexes. Complexes are cross-linked by short treatments with formaldehyde after reaching binding equilibrium. Cross-linked complexes are separated by electrophoretic mobility using free solution CE or by size using sieving electrophoresis of SDS complexes. The method gives good quantitative results; e.g., a lysozyme-antibody interaction was found to have Kd = 24 ± 3 nM by PXCE and Kd = 17 ± 2 nM using isothermal calorimetry (ITC). Heat shock protein 70 (Hsp70) in complex with bcl2 associated athanogene 3 (Bag3) was found to have Kd = 25 ± 5 nM by PXCE which agrees with Kd values reported without cross-linking. Hsp70-Bag3 binding site mutants and small molecule inhibitors of Hsp70-Bag3 were characterized by PXCE with good agreement to inhibitory constants and IC50 values obtained by a bead-based flow cytometry protein interaction assay (FCPIA). PXCE allows rapid method development for quantitative analysis of PPIs. PMID:27434096

  8. Capillary electrophoresis as a screening tool for alpha amylase inhibitors in plant extracts

    PubMed Central

    Hamdan, Imad I.; Afifi, Fatima U.

    2010-01-01

    Capillary electrophoresis (CE) method was developed for screening plant extract for potential alpha amylase (AA) inhibitory activity. The method was validated against a well established UV method. Overall, the proposed method was shown able to detect plants with significant alpha amylase inhibitory activity but not those with rather clinically insignificant activities. Fifty plant species were screened using both the proposed CE method and the UV method and seven plant species were found to possess significant AA inhibitory activities. Two plant species were proved to have alpha amylase inhibitory activity for the first time. PMID:24115900

  9. High-throughput viscosity measurement using capillary electrophoresis instrumentation and its application to protein formulation.

    PubMed

    Allmendinger, Andrea; Dieu, Le-Ha; Fischer, Stefan; Mueller, Robert; Mahler, Hanns-Christian; Huwyler, Jörg

    2014-10-01

    Viscosity characterization of protein formulations is of utmost importance for the development of subcutaneously administered formulations. However, viscosity determinations are time-consuming and require large sample volumes in the range of hundreds of microliters to a few milliliters, depending on the method used. In this article, an automated, high-throughput method is described to determine dynamic viscosity of Newtonian fluids using standard capillary electrophoresis (CE) equipment. CE is an analytical method routinely used for the separation and characterization of proteins. In our set-up, the capillary is filled with the test sample, and a constant pressure is applied. A small aliquot of riboflavin is subsequently loaded into the capillary and used as a dye to monitor movement of protein samples. Migration time of the riboflavin peak moving through the filled capillary is converted to the viscosity by applying the Hagen-Poiseuille's law. The instrument is operated without using an electrical field. Repeatability, robustness, linearity, and reproducibility were demonstrated for different capillary lots and instruments, as well as for different capillary lengths and diameters. Accuracy was verified by comparing the viscosity data obtained by CE instrumentation with those obtained by plate/cone rheometry. The suitability of the method for protein formulations was demonstrated, and limitations were discussed. Typical viscosities in the range of 5-40mPas were reliably measured with this method. Advantages of the CE instrumentation-based method included short measurement times (1-15min), small sample volumes (few microliters) for a capillary with a diameter of 50μm and a length of 20.5cm as well as potential to be suitable for high-throughput measurements.

  10. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2012-2014).

    PubMed

    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

    2015-01-01

    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.

  11. Capillary electrophoresis: Imaging of electroosmotic and pressure driven flow profiles in fused silica capillaries

    NASA Technical Reports Server (NTRS)

    Williams, George O., Jr.

    1996-01-01

    This study is a continuation of the summer of 1994 NASA/ASEE Summer Faculty Fellowship Program. This effort is a portion of the ongoing work by the Biophysics Branch of the Marshall Space Flight Center. The work has focused recently on the separation of macromolecules using capillary electrophoresis (CE). Two primary goals were established for the effort this summer. First, we wanted to use capillary electrophoresis to study the electrohydrodynamics of a sample stream. Secondly, there was a need to develop a methodology for using CE for separation of DNA molecules of various sizes. In order to achieve these goals we needed to establish a procedure for detection of a sample plug under the influence of an electric field Detection of the sample with the microscope and image analysis system would be helpful in studying the electrohydrodynamics of this stream under load. Videotaping this process under the influence of an electric field in real time would also be useful. Imaging and photography of the sample/background electrolyte interface would be vital to this study. Finally, detection and imaging of electroosmotic flow and pressure driven flow must be accomplished.

  12. A simple and fast method for chlorsulfuron and metsulfuron methyl determination in water samples using multiwalled carbon nanotubes (MWCNTs) and capillary electrophoresis.

    PubMed

    Springer, Valeria H; Lista, Adriana G

    2010-11-15

    A new method to determine metsulfuron methyl (MSM) and chlorsulfuron (CS) in different water samples was developed. It consists in a solid phase extraction (SPE) procedure using multiwalled carbon nanotubes (MWCNTs) as sorbent material in combination with capillary zone electrophoretic determination. To carry out the pre-concentration step, a simple flow injection system was developed and optimized. Thus, 250 μL of aqueous solution containing methanol 50% (v/v) and acetonitrile 2% (v/v) as eluent, 10 mL of sample and a flow rate of 1.15 mL min(-1) were selected. The CE variables also were optimized. A rapid determination and good resolution of two herbicides were obtained within 9 min using a simple electrophoretic buffer (50 mmol L(-1) sodium tetraborate with 3% of methanol, pH=9.0). Under the optimum conditions, the calibration curves were linear between 0.5 and 6 μg L(-1) for MSM and CS with R(2)=0.995 and 0.997, respectively. The repeatability of the proposed method, expressed as relative standard deviation (RSD), varied between 4.1% and 5.4% (n=10) and the detection limits for MSM and CS were 0.40 and 0.36 μg L(-1), respectively. Good results were achieved when the proposed method was applied to spiked real water samples. The recoveries percentages of the two analytes were over the range 86-108%. PMID:21035652

  13. Capillary zone electrophoresis method for the direct determination of amino acids in recombinant human erythropoietin preparations used for the treatment of anemia.

    PubMed

    de Souza Crespo, Izabel Cristina; de Resende, Matheus Troina; Pereira Netto, Annibal Duarte; de Carvalho Marques, Flávia Ferreira

    2015-05-01

    A method based on CZE for the determination of glutamic acid, glycine, and alanine in a biopharmaceutical formulation containing recombinant human erythropoietin was developed. The separation was achieved within less than 5 min, using a fused-silica capillary column (55 cm × 50 μm id) and 30 mmol/L phosphate buffer at pH 11.5, containing 0.6 mmol/L CTAB and 10% v/v methanol, as BGE solution. Applied potential of -25 kV, temperature of 15°C and hydrodynamic injection time of 15 s, at 50 mbar, were employed. The detection of the analytes was carried out without any derivatization reaction, at 220 nm using an UV-DAD detector. Linear ranges from 50 to 2500 mg/L and quantification limits of 40, 39, and 37 mg/L were obtained for glutamic acid, glycine, and alanine, respectively. Sample preparation required only a dilution step. Considering peak area and migration time values, the method presented good repeatability (RSD <1.7%; n = 9) and intermediate precision (RSD <1.0%; n = 6). Recovery evaluation using a commercial sample led to values between 97.5 ± 5.2% and 101.5 ± 4.6%, demonstrating the feasibility of the method, which was successfully applied in the quantification of the amino acids of interest in biopharmaceutical samples.

  14. Analysis of serotonin in brain microdialysates using capillary electrophoresis and native laser-induced fluorescence detection.

    PubMed

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

    2005-03-01

    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.

  15. Capillary electrophoresis of sialylated oligosaccharides in milk from different species.

    PubMed

    Monti, Lucia; Cattaneo, Tiziana Maria Piera; Orlandi, Mario; Curadi, Maria Claudia

    2015-08-28

    Oligosaccharides are relevant components of human milk, which have been quite well studied for their pre-biotic effect and their capacity in stimulating the immune system. Since oligosaccharides from milk of non-human mammals received so far less attention, the aim of this work was the application of capillary electrophoresis (CE) for the analysis of sialylated oligosaccharides in cow, goat and equine (mare and donkey) milk to possibly identify potential sources of oligosaccharides to use as health promoting ingredients in functional foods. Human milk was used as reference milk. A recent CE technique was applied to resolve and quantify 3-sialyllactose (3-SL), 6-sialyllactose (6-SL) and disialyl-lacto-N-tetraose (DSLNT). Analysis of non-human milk samples confirmed differences among species and individuals: DSLNT, which was the most abundant compound in human milk (455-805μg/mL) was missing in most of the samples. In most cases, 3-SL showed to be the most concentrated of the quantified analytes, with values ranging from 12 to 77μg/mL.

  16. Combining Capillary Electrophoresis with Mass Spectrometry for Applications in Proteomics

    SciTech Connect

    Simpson, David C.; Smith, Richard D.

    2005-04-01

    Throughout the field of global proteomics, ranging from simple organism studies to human medical applications, the high sample complexity creates demands for improved separations and analysis techniques. Furthermore, with increased organism complexity, the correlation between proteome and genome becomes less certain due to extensive mRNA processing prior to translation. In this way, the same DNA sequence can potentially code for regions in a number of distinct proteins; quantitative differences in expression (or abundance) between these often-related species are of significant interest. Well-established proteomics techniques, which use genomic information to identify peptides that originate from protease digestion, often cannot easily distinguish between such gene products; intact protein-level analyses are required to complete the picture, particularly for identifying post-translational modifications. While chromatographic techniques are currently better suited to peptide analysis, capillary electrophoresis (CE) in combination with mass spectrometry (MS) may become important for intact protein analysis. This review focuses on CE/MS instrumentation and techniques showing promise for such applications, highlighting those with greatest potential. Reference will also be made to developments relevant to peptide-level analyses for use in time- or sample-limited situations.

  17. Chiral separation of benzoporphyrin derivative mono- and diacids by laser induced fluorescence-capillary electrophoresis.

    PubMed

    Peng, Xuejun; Sternberg, Ethan; Dolphin, David

    2002-01-01

    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.

  18. Chiral separation of benzoporphyrin derivative mono- and diacids by laser induced fluorescence-capillary electrophoresis.

    PubMed

    Peng, Xuejun; Sternberg, Ethan; Dolphin, David

    2002-01-01

    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. PMID:11824627

  19. Study of the Electrophoretic Behavior of Cephalosporins by Capillary Zone Electrophoresis

    PubMed Central

    Hancu, Gabriel; Sasebeşi, Adina; Rusu, Aura; Kelemen, Hajnal; Ciurba, Adriana

    2015-01-01

    Purpose: The aim of the study was the characterization of the electrophoretic behavior of cephalosporins from different generation having different structural characteristics in order to develop a rapid, simple and efficient capillary electrophoretic method for their identification and simultaneous separation from complex mixtures. Methods: Ten cephalosporin derivatives (cefaclor, cefadroxil, cefalexin, cefazolin, cefoxitin, cefuroxime, cefoperazone, cefotaxime, ceftazidime, ceftriaxone) were analyzed by capillary zone electrophoresis using different background electrolyte solutions at different pH values. Electrophoretic mobilities of the analytes were calculated, the influence of the electrophoretic parameteres on the separation was established and the analytical conditions were optimized. Results: Taking into consideration their structural and chemical properties cephalosporins can be detected over a pH range between 6 and 10. The best results were obtained using a buffer solution containing 25 mM disodium hydrogenophosphate - 25 mM sodium dihydrogenophosphate, at a pH – 7.00, + 25 kV voltage at a temperature of 25 °C, UV detection at 210 nm. Using the optimized analytical conditions we achieved the simultaneous baseline separation for seven cephalosporins in less then 10 minutes. Conclusion: Using the described optimized electrophoretic procedures, capillary electrophoresis can be used for the identification and determination of cephalosporins in formulated pharmaceutical products and for their separation from complex mixtures. PMID:26236661

  20. Raman spectroscopy and capillary electrophoresis applied to forensic colour inkjet printer inks analysis.

    PubMed

    Król, Małgorzata; Karoly, Agnes; Kościelniak, Paweł

    2014-09-01

    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.

  1. Capillary electrophoresis to quantitate gossypol enantiomers in cotton flower petals and seed.

    PubMed

    Vshivkov, Sergey; Pshenichnov, Egor; Golubenko, Zamira; Akhunov, Alik; Namazov, Shadman; Stipanovic, Robert D

    2012-11-01

    Gossypol is a toxic compound that occurs as a mixture of enantiomers in cotton plant tissues including seed and flower petals. The (-)-enantiomer is more toxic to non-ruminant animals. Efforts to breed cottonseed with a low percentage of (-)-gossypol requires determination of the (+)- to (-)-gossypol ratio in seed and flower petals. We report a method to quantitatively determine the total gossypol and percent of its enantiomers in cotton tissues using high performance capillary electrophoresis (HPCE). The method utilizes a borate buffer at pH 9.3 using a capillary with internal diameter of 50μm, effective length of 24.5cm, 15kV and cassette temperature of 15°C. This method provides high accuracy and reproducible results with a limit of detection of the individual enantiomers of less than 36ng/mL providing base line separation in less than 6min. PMID:23122406

  2. Merging a sensitive capillary electrophoresis-ultraviolet detection method with chemometric exploratory data analysis for the determination of phenolic acids and subsequent characterization of avocado fruit.

    PubMed

    Hurtado-Fernández, Elena; Contreras-Gutiérrez, Paulina K; Cuadros-Rodríguez, Luis; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto

    2013-12-15

    Herein we present the development of a powerful CE-UV method able to detect and quantify an important number of phenolic acids in 13 varieties of avocado fruits at 2 ripening stages. All the variables involved in CE separation were exhaustively optimized and the best results were obtained with a capillary of 50 μm i.d. × 50 cm effective length, sodium tetraborate 40 mM at a pH of 9.4, 30 kV, 25 °C, 10s of hydrodynamic injection (0.5 psi) and UV detection at 254 nm. This optimal methodology was fully validated and then applied to different avocado samples. The number of phenolic acids determined varied from 8 to 14 compounds; in general, they were in concentrations ranging from 0.13 ppm to 3.82 ppm, except p-coumaric, benzoic and protocatechuic acids, which were found at higher concentrations. Principal component analysis (PCA) was applied to highlight the differences between varieties and ripening degrees, looking for the most influential analytes. PMID:23993512

  3. Merging a sensitive capillary electrophoresis-ultraviolet detection method with chemometric exploratory data analysis for the determination of phenolic acids and subsequent characterization of avocado fruit.

    PubMed

    Hurtado-Fernández, Elena; Contreras-Gutiérrez, Paulina K; Cuadros-Rodríguez, Luis; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto

    2013-12-15

    Herein we present the development of a powerful CE-UV method able to detect and quantify an important number of phenolic acids in 13 varieties of avocado fruits at 2 ripening stages. All the variables involved in CE separation were exhaustively optimized and the best results were obtained with a capillary of 50 μm i.d. × 50 cm effective length, sodium tetraborate 40 mM at a pH of 9.4, 30 kV, 25 °C, 10s of hydrodynamic injection (0.5 psi) and UV detection at 254 nm. This optimal methodology was fully validated and then applied to different avocado samples. The number of phenolic acids determined varied from 8 to 14 compounds; in general, they were in concentrations ranging from 0.13 ppm to 3.82 ppm, except p-coumaric, benzoic and protocatechuic acids, which were found at higher concentrations. Principal component analysis (PCA) was applied to highlight the differences between varieties and ripening degrees, looking for the most influential analytes.

  4. High-performance capillary electrophoresis determination of pyrithione in antidandruff preparations and shampoos.

    PubMed

    Peña-Méndez, E M; Havel, J; Malecek, J

    1997-01-01

    A simple and rapid high-performance capillary electrophoresis (HPCE) method for the determination of 2-mercaptopyridine-1-oxide (pyrithione) was developed. After addition of ethylenediaminetetraacetic acid (EDTA), pyrithione was determined in the form of the free anion using 50 mM borate (pH 9.2) as background electrolyte and was detected at 244 nm with a limit of detection (LOD) of 0.636 ppm (S/N = 3). The method was used to check the purity of pyrithione preparations and for the determination of pyrithione in shampoo.

  5. Application of capillary electrophoresis for the determination of inorganic ions in trace explosives and explosive residues.

    PubMed

    Kishi, T; Nakamura, J; Arai, H

    1998-01-01

    Capillary electrophoresis was developed for the analysis of low explosive residue, because a significant amount of inorganic anions and cations remain after deflagration. Certain high explosives, such as emulsion explosives, produce a vast quantity of inorganic ions after a blast and can readily be analyzed using capillary electrophoresis. Often, trace amounts of explosive residues may be present on physical evidence submitted in criminal cases. Trace amounts of inorganic ions such as nitrate, chlorate, and ammonium may be detected using capillary electrophoresis owing to the low detection limit of these species. The utility of capillary electrophoresis in the analysis of explosive residues is in its ability to simultaneously analyze trace explosives and ionic products present on physical evidence. PMID:9511855

  6. IDENTIFICATION OF REACTIVE DYES IN SPENT DYEBATHS AND WASTEWATER BY CAPILLARY ELECTROPHORESIS/MASS SPECTROMETRY

    EPA Science Inventory

    Capillary electrophoresis with diode array detection and mass spectrometry combined with solid-phase extraction were employed for the identification of reactive vinylsulfone and chlorotriazine dyes and their hydrolysis products in spent dyebaths and raw and treated wastewater. Re...

  7. INFLUENCE OF BORATE BUFFERS ON THE ELECTROPHORETIC BEHAVIOR OF HUMIC SUBSTANCES IN CAPILLARY ZONE ELECTROPHORESIS

    EPA Science Inventory

    The influence of tetrahydroxyborate ions on the electrophoretic mobility of humic acids was evaluated by capillary electrophoresis (CE). Depending on the molarity of borate ions in the separation buffer, the humic acids exhibit electropherograms with sharp peaks consistently exte...

  8. Application of capillary electrophoresis for the determination of inorganic ions in trace explosives and explosive residues.

    PubMed

    Kishi, T; Nakamura, J; Arai, H

    1998-01-01

    Capillary electrophoresis was developed for the analysis of low explosive residue, because a significant amount of inorganic anions and cations remain after deflagration. Certain high explosives, such as emulsion explosives, produce a vast quantity of inorganic ions after a blast and can readily be analyzed using capillary electrophoresis. Often, trace amounts of explosive residues may be present on physical evidence submitted in criminal cases. Trace amounts of inorganic ions such as nitrate, chlorate, and ammonium may be detected using capillary electrophoresis owing to the low detection limit of these species. The utility of capillary electrophoresis in the analysis of explosive residues is in its ability to simultaneously analyze trace explosives and ionic products present on physical evidence.

  9. APPLICATIONS OF CAPILLARY ELECTROPHORESIS/LASER-INDUCED FLUORESCENCE DETECTION TO GROUND WATER MIGRATION STUDIES

    EPA Science Inventory

    Capillary electrophoresis (CE) has been applied to the determination of groundwater migration based on laser-induced fluorescence (LIF) detection and traditional spectrofluorimetry. The detection limits of injected dye-fluorescent whitening agent (tinopal) in the low parts per tr...

  10. CAPILLARY ELECTROPHORESIS/LASER-INDUCED FLUORESCENCE DETECTION OF FLUORESCEIN AS A GROUNDWATER MIGRATION TRACER

    EPA Science Inventory

    Capillary electrophoresis (CE) has been applied to the determination of the groundwater migration tracer dye fluorescein based on laser-induced fluorescence (LIF) detection and compared to determinations obtained with traditional spectrofluorimetry. Detection limits of injected d...

  11. DNA profiling by capillary array electrophoresis with non-covalent fluorescent labeling.

    PubMed

    Olson, Nels A; Khandurina, Julia; Guttman, Andras

    2004-10-01

    Increasing need for large-scale DNA profiling necessitated the development of automated electrophoresis based methods enabling rapid, high performance analysis of nucleic acids in a wide molecular-mass range. In this paper, we report on the adaptation of a commercial 96-capillary array electrophoresis (CAE) instrument for high-throughput DNA fragment analysis and the evaluation of the effects of different non-covalent DNA staining dyes on separation efficiency. The applicability of different color internal fluorescent standards is shown with mathematical spectral overlap correction algorithms. Large-scale quality control assessment of oligonucleotide probes using non-covalent fluorophore labeling is also demonstrated. The method requires small sample amounts, offers automation and quantification capabilities to accommodate modern biotechnology industry needs.

  12. Microbial Analysis of Escherichia coli ATCC, Lactobacteria and Saccharomyces cerevisiae Using Capillary Electrophoresis Approach.

    PubMed

    Pomastowski, Paweł; Railean-Plugaru, Viorica; Buszewski, Bogusław

    2016-01-01

    Rapid detection and identification of microorganisms is a challenging and important aspect in many areas of our life, beginning with medicine, ending with industry. Unfortunately, classical methods of microorganisms identification are based on time-consuming and labor-intensive approaches. Screening techniques require rapid and cheap grouping of bacterial isolates; however, modern bioanalytics demands comprehensive bacterial studies on molecular level. The new approach to the rapid identification of bacteria is to use the electromigration techniques, especially capillary zone electrophoresis (CZE). CZE is an important technique used in the analysis of microorganisms. However, the analysis of microbial complexes using this technology still encounters several problems-uncontrolled aggregation and/or adhesion to the capillary surface. One way to resolve this issue is the CZE analysis of microbial cell with surface charge modification by bivalent metal ions (e.g., Ca(2+) aq, Zn aq). Under the above conditions, bacterial cells create compact aggregates, and fewer high-intensity signals are observed in electropherograms. The chapter presents the capillary electrophoresis of microbial aggregates approach with UV and one-dimensional intact cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (ICM MS) detection. PMID:27645746

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

    SciTech Connect

    Fung, N.

    1998-03-27

    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.

  14. Role of capillary electrophoresis in the fight against doping in sports.

    PubMed

    Harrison, Christopher R

    2013-08-01

    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.

  15. Evalution of capillary electrophoresis-frontal analysis for the study of low molecular weight drug-human serum albumin interactions.

    PubMed

    Østergaard, Jesper; Schou, Christian; Larsen, Claus; Heegaard, Niels H H

    2002-09-01

    Capillary electrophoresis frontal analysis was applied to 12 low molecular weight compounds including 8 drug substances displaying a range of different properties with respect to binding affinity, binding location, structure, lipophilicity, charge at physiological pH, and electrophoretic mobility. It was found that capillary electrophoresis frontal analysis can be used as a general method to study and quantify drug-human serum albumin interactions. The binding parameters obtained were consistent with literature values. Dextran was in some cases added to the run buffer to improve separation of the drug and human serum albumin plateau peaks. Results indicate that mobility differences between free and complexed human serum albumin give rise to only minor errors. Capillary electrophoresis frontal analysis was also found applicable to the study of human serum albumin drug displacement reactions. Low sensitivity of the UV-detection system was found to be the major limitation of capillary electrophoresis frontal analysis. The method is simple, and minimal effort has to be put into method development, which makes it well suited for screening in early drug development.

  16. Development and validation of an analytical method for the separation and determination of major bioactive curcuminoids in Curcuma longa rhizomes and herbal products using non-aqueous capillary electrophoresis.

    PubMed

    Anubala, S; Sekar, R; Nagaiah, K

    2014-06-01

    A simple, fast and efficient non-aqueous capillary electrophoresis method (NACE) was developed for the simultaneous determination of three major bioactive curcuminoids (CMNs) in Curcuma longa rhizomes and its herbal products. Good separation, resolution and reproducibility were achieved with the background electrolyte (BGE) consisting a mixture of 15.0 mM sodium tetraborate and 7.4 mM sodium hydroxide (NaOH) in 2:10:15 (v/v/v) of water, 1-propanol, and methanol. The influences of background electrolyte, sodium hydroxide, water, sodium dodecyl sulfate and hydroxylpropyl-β-cyclodextrin on separations were investigated. The separation was carried out in a fused-silica capillary tube with reverse polarity. Hydrodynamic injection of 25mbar for 12s was used for injecting samples and a voltage of 28 kV was applied for separation. The ultrasonication method was used for the extraction of CMNs from the turmeric herbal products and the extract was filtered and directly injected without any further treatments. The limits of detection and quantification were less than 5.0 and 14.6 µg/ml respectively for all CMNs. The percentage recoveries for CMNs were >97.2% (%RSD, <2.62). The results obtained by the method were compared with existing spectrophotometric and HPLC methods. The related compounds in the extract did not interfere in the determination of CMNs. The proposed NACE method is better than existing chromatographic and electrophoretic methods in terms of simple electrophoretic medium, fast analysis and good resolution.

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

    SciTech Connect

    Zhang Liling

    1996-01-02

    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.

  18. Capillary electrophoresis: Biotechnology for separation of DNA and chromosomes

    NASA Technical Reports Server (NTRS)

    Williams, George O., Jr.

    1994-01-01

    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.

  19. Determination of amino acids in fodders and raw materials using capillary zone electrophoresis.

    PubMed

    Komarova, N V; Kamentsev, J S; Solomonova, A P; Anufrieva, R M

    2004-02-01

    Two schemes were offered for analysis of amino acid contents in fodders and raw materials for mixed fodders by capillary zone electrophoresis (CZE). The first variant provides express analysis of four technologically important amino acids (lysine, methionine, threonine, cystine) in borate buffer on characteristic absorption of aminogroup (190 nm), with limits of quantitation being on average 0.2%. The second scheme includes pre-capillary derivatization of amino acids using phenylisothiocyanate (PITC) and separation of phenylthiocarbamyl (PTC)-derivatives obtained by CZE with a detection on 254 nm, which allows to widen a list of detectable components up to 19 (without tryptophan) and significantly improve detection limits down to 0.01%. Acid hydrolysis was used for a sample preparation. The results of analysis of fodders were compared using such methods, as CZE, ion exchange chromatography (amino acid analyzer) and reversed-phase (RP)-HPLC (with gradient technique of elution). PMID:14698247

  20. Enantioresolution of pharmaceutical compounds by capillary electrophoresis. Use of cyclodextrins and antibiotics.

    PubMed

    Fanali, S; Aturki, Z; Desiderio, C

    1999-01-01

    Capillary electrophoresis (CE) is a powerful tool for the analysis of chiral compounds of pharmaceutical interest. The separation of enantiomers can be achieved using a chiral environment responsible for the diastereoisomers formation (stable or labile in the indirect or direct separation method, respectively). A wide number of chiral selectors have been employed in CE and among them cyclodextrins or their derivatives and antibiotics are the most used stereoselective agents. The review surveys the chiral separation of drugs using the above mentioned chiral selectors by CE. The main parameters influencing the enantioresolution, e.g., chiral selector type and concentration, buffer type, concentration, pH, organic modifier as well as the capillary temperature are discussed. Finally some selected applications to real samples such as pharmaceutical formulations, serum, urine are also discussed.

  1. CAPILLARY ELECTROPHORESIS COUPLED ON-LINE WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY FOR ELEMENTAL SPECIATION

    EPA Science Inventory

    A novel interface to connect a capillary electrophoresis (CE) system with an inductively coupled plasma mass spectrometric (ICPMS) detector is reported here. The interface was built using a direct injection nebulizer (DIN) system. In this interface, the CE capillary was placed co...

  2. ANALYSIS OF ANIONIC METALLIZED AZO AND FORMAZAN DYES BY CAPILLARY ELECTROPHORESIS/MASS SPECTROMETRY

    EPA Science Inventory

    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...

  3. Capillary Electrophoresis Analysis of Cations in Water Samples: An Experiment for the Introductory Laboratory

    ERIC Educational Resources Information Center

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

    2004-01-01

    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…

  4. Rapid determination of sodium in milk and milk products by capillary zone electrophoresis.

    PubMed

    Masotti, F; Erba, D; De Noni, I; Pellegrino, L

    2012-06-01

    A capillary zone electrophoresis method for the determination of Na in milk and milk products was developed and compared with an International Organization for Standardization/International Dairy Federation standard method that is based on flame atomic absorption spectrometry. The adoption of a background electrolyte consisting of 10 mM imidazole adjusted to pH 3.75 by the addition of oxalic acid allowed baseline separation of Na from other milk cations and from Li ion, which was adopted as an internal standard. Method validation was performed and the results for linearity, precision, limit of detection, limit of quantification, and recovery are presented. The procedure was tested on commercial milk samples differing in fat content (whole, semiskimmed, and skimmed) and processing conditions (pasteurization, UHT sterilization, and microfiltration). The reliability of the method was confirmed for different varieties of cheese and other milk products. The method enables the routine measurement of Na content by a rapid and accurate capillary zone electrophoresis procedure. PMID:22612924

  5. Analysis of lipoproteins by capillary zone electrophoresis in microfluidic devices: assay development and surface roughness measurements.

    PubMed

    Weiller, Bruce H; Ceriotti, Laura; Shibata, Takayuki; Rein, Dietrich; Roberts, Matthew A; Lichtenberg, Jan; German, J Bruce; de Rooij, Nico F; Verpoorte, Elisabeth

    2002-04-01

    The development of a new assay for lipoproteins by capillary electrophoresis in fused-silica capillaries and in glass microdevices is described in this paper. The separation of low-density (LDL) and high-density (HDL) lipoproteins by capillary zone electrophoresis is demonstrated in fused-silica capillaries with both UV absorption and laser-induced fluorescence detection. This separation was accomplished using Tricine buffer (pH 9.0) with methylglucamine added as a dynamic coating. With UV detection, LDL eluted as a relatively sharp peak with a migration time of approximately 11 min and HDL eluted as a broad peak with a migration time of 12.5 min. Fluorescence detection of lipoproteins stained with NBD-ceramide was used with the same buffer system to give comparable results. Furthermore, fluorescence staining of human serum samples yielded results similar to the fluorescently stained LDL and HDL fractions, showing that this method can be used to quantify lipoproteins in serum samples. The method was also used to detect lipoproteins in glass micro-CE devices. Very similar results were obtained in microdevices although with much faster analysis times, LDL eluted as a sharp peak at approximately 25 s and HDL as a broad peak at slightly longer time. In addition, higher resolution was obtained on chips. To our knowledge, these results show the first separation and detection of lipoproteins in a microfluidic device using native serum samples. Atomic force microscopy was used to characterize the rms surface roughness (Rq) of microfluidic channels directly. Devices with different surface roughness values were fabricated using two different etchants for Pyrex wafers with a polysilicon masking layer. Using 49% HF, the measured roughness is Rq = 10.9 +/- 1.6 nm and with buffered HF (NH4F + HF) the roughness is Rq = 2.4 +/- 0.7 nm. At this level of surface roughness, there is no observable effect on the performance of the devices for this lipoprotein separation.

  6. On-Line Solid-Phase Extraction Capillary Electrophoresis Mass Spectrometry for Preconcentration and Clean-Up of Peptides and Proteins.

    PubMed

    Benavente, Fernando; Medina-Casanellas, Silvia; Giménez, Estela; Sanz-Nebot, Victoria

    2016-01-01

    One of the major drawbacks of capillary electrophoresis (CE) and other microscale separation techniques, for the analysis of low abundant peptides and proteins in complex samples, are the poor concentration limits of detection. Several strategies have been developed to improve CE sensitivity. Here, we describe an on-line solid-phase extraction capillary electrophoresis mass spectrometry method with a commercial C18 sorbent for clean-up and preconcentration of neuropeptides from highly diluted biological samples.

  7. Capillary ion electrophoresis of endogenous anions and anionic adulterants in human urine.

    PubMed

    Ferslew, K E; Hagardorn, A N; Robert, T A

    2001-05-01

    Normal human urine contains many anions and cations. Ionic concentrations in urine have classically been determined by spectrophotometry of color reactions, flame emission spectrophotometry, atomic absorption spectrophotometry, high performance liquid chromatography, or potentiometry with ion-specific electrodes. Capillary ion electrophoresis (CIE) is a form of capillary electrophoresis which uses the differential electrophoretic mobility of ions to perform a separation of an ionic mixture. Various salts can be added to urine specimens to abnormally elevate ionic concentrations and interfere with either immunoassay urine drug screening procedures or gas chromatographic/mass spectrometric confirmation techniques. Application of CIE for the direct detection of endogenous anions and anionic adulterants in human urine specimens was the purpose of this investigation. CIE was performed using a Waters Quanta 4000 Capillary Electrophoresis System with either direct or indirect ultraviolet absorption detection at 254 nm. CIE of 30 random normal urine specimens and 21 urine specimens suspected of adulteration was performed. Duplicate aliquots were assayed by CIE and by colorimetric technique for nitrite. Sixteen specimens had elevated concentrations of nitrite and/or nitrate. The correlation coefficient between nitrite CIE and colorimetric results was 0.9895. Three specimens had detectable concentrations of chromate and were suspected of being adulterated with "Urine Luck," an adulterant found to contain chromate. Two specimens suspected of being adulterated with bleach were found to only contain chloride, sulfate, and phosphate. CIE is applicable to forensic analysis of urine anion concentrations. CIE can easily quantitate numerous endogenous anions and offers a method to detect and/or confirm anion adulteration of urine specimens. PMID:11372999

  8. Impact of capillary conditioning and background electrolyte composition on capillary electrophoresis analysis of prostate specific antigen isoforms.

    PubMed

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

    2016-04-22

    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. PMID:27018191

  9. Analysis of neuropeptides using capillary zone electrophoresis with multichannel fluorescence detection

    NASA Astrophysics Data System (ADS)

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

    1991-12-01

    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. Thermally-initiated free radical polymerization for reproducible production of stable linear polyacrylamide coated capillaries, and their application to proteomic analysis using capillary zone electrophoresis-mass spectrometry.

    PubMed

    Zhu, Guijie; Sun, Liangliang; Dovichi, Norman J

    2016-01-01

    Proteomic analysis using capillary zone electrophoresis (CZE) typically is performed with linear polyacrylamide (LPA) coated capillaries. These capillaries both minimize the adsorption of peptides and proteins to the inner wall of the capillary and decrease electroosmosis, which increases the separation capacity. LPA coating protocols were first reported by Hjerten in 1985. Conventional LPA production is based on the use of tetramethylethylenediamine (TEMED) to catalyze the free-radical polymerization that couples acrylamide to a capillary wall that has been pretreated with γ-methacryloxypropyltrimethoxysilane. The treated capillary is filled with a mixture of monomer, TEMED, and ammonium persulfate; free radical polymerization forms the LPA coating. Over many years, we have observed significant variation in the electroosmotic properties of commercial LPA coated capillaries both along the capillary length and between lots. We believe this variation is due to differences in the time between initiation of the reaction and the filling of the capillary. Here, we report a simple method for the generation of very stable and reproducible coatings. In this protocol, the monomer mixture and an ammonium persulfate initiator are introduced into the capillary without TEMED initiator. The mixture is stable and does not begin polymerization at room temperature. The filled capillary is then heated in a water bath to initiate polymerization in a well-controlled manner. A mixture of four standard proteins was used to evaluate the coating performance. Compared with commercialized LPA capillaries, our LPA capillaries generate much better separation performance and superior protein peak shape in CZE analysis. We also analyzed an intact antibody (MW 150K) by CZE-MS with the new LPA capillary in triplicate runs. The intact antibody generated a Gaussian-shaped electrophoresis peak with 1.2% relative standard deviation in migration time and 8.5% in base peak intensity. An automated CZE

  11. Rapid identification and quantitation for oral bacteria based on short-end capillary electrophoresis.

    PubMed

    Chen, Jin; Ni, Yi; Liu, Chenchen; Yamaguchi, Yoshinori; Chen, Qinmiao; Sekine, Shinichi; Zhu, Xifang; Dou, Xiaoming

    2016-11-01

    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. PMID:27591633

  12. Separation of attogram terpenes by the capillary zone electrophoresis with fluorometric detection.

    PubMed

    Kubesová, Anna; Horká, Marie; Růžička, Filip; Slais, Karel; Glatz, Zdeněk

    2010-11-12

    An original method based on capillary zone electrophoresis with fluorimetric detection has been developed for the determination of terpenic compounds. The method is based on the separation of a terpenes dynamically labeled by the non-ionogenic tenside poly(ethylene glycol) pyrenebutanoate, which was used previously for the labeling of biopolymers. The background electrolytes were composed of taurine-Tris buffer (pH 8.4). In addition to the non-ionogenic tenside aceton and poly(ethylene glycol) were used as the additives. The capillary zone electrophoresis with fluorometric detection at the excitation wavelength 335 nm and the emission wavelength 463 nm was successfully applied to the analysis of tonalid, cholesterol, vitamin A, ergosterol, estrone and farnesol at level of 10(-17) mol L(-1). Farnesol, is produced by Candida albicans as an extracellular quorum-sensing molecule that influences expression of a number of virulence factors, especially morphogenesis and biofilm formation. It enables this yeast to cause serious nosocomial infections. The sensitivity of this method was demonstrated on the separation of farnesol directly from the cultivation medium.

  13. Determination of ephedrine and pseudoephedrine by field-amplified sample injection capillary electrophoresis.

    PubMed

    Deng, Dongli; Deng, Hao; Zhang, Lichun; Su, Yingying

    2014-04-01

    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.

  14. Recent advances in amino acid analysis by capillary electrophoresis.

    PubMed

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

    2012-01-01

    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.

  15. An axial approach to detection in capillary electrophoresis

    SciTech Connect

    Taylor, J.A.

    1993-05-01

    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.

  16. Simultaneous determination of phenylethanoid glycosides and aglycones by capillary zone electrophoresis with running buffer modifier.

    PubMed

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

    2014-03-15

    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.

  17. Determination of trimebutine maleate in rat plasma and tissues by using capillary zone electrophoresis.

    PubMed

    Li, F; Yu, L

    2001-06-01

    A simple and rapid capillary zone electrophoresis method was developed for the determination of trimebutine maleate in rat plasma and tissues. Rat plasma and tissue homogenates were mixed with acetonitrile containing internal standard, ephedrine hydrochloride, and then centrifuged. The supernatant was dried under a stream of nitrogen, and the residue was reconstituted in methanol-water (1:1). The electrophoresis was performed in uncoated capillary with 30 mmol/L phosphate buffer of pH 6.0 as the separation electrolyte. The applied voltage was 10 kV and the UV detection was set at 214 nm. The peak height ratio vs concentration in plasma or homogenates was linear over the range of 5-500 ng/mL and the limit of quantitation was 5 ng/mL. The intra- and inter-day precision was RSD < 14% and <15%. The accuracy was relative error (RE) within +/- 14%. This method was applied to studying the pharmacokinetics and tissue distribution after a single dose of trimebutine maleate was administrated to the rats. The T(max), AUC, C(max) and t(1/2) were 30 min, 7.8 x 10(2) (ng/mL) min, 39 ng/mL and 1.7 x 10(2) min. The drug distribution was found in a decreasing order of liver, kidney, spleen, lung and heart. PMID:11438965

  18. Separation and determination of flavonoids in three traditional chinese medicines by capillary electrophoresis with amperometric detection.

    PubMed

    Wang, Wei; Lin, Ping; Ma, Lihong; Xu, Kaixuan; Lin, Xiuli

    2016-04-01

    Flavonoids are important active ingredients in many traditional Chinese medicines. In this paper, capillary electrophoresis with amperometric detection was employed to separate and detect eight flavonoids, rutin, quercetrin, quercetin, kaempferol, kaempferide, catechin, apigenin, and luteolin, in a home-made capillary electrophoresis device. Under the separation voltage of 2000 V, the eight flavonoids could be completely separated within 33 min in 18 mM borax running buffer at pH 10.2. Good linear relationships were obtained for all analytes and the detection limits for flavonoids ranged from 0.46 to 0.85 μM. Then, the method was applied to separate and determine the flavonoids in three traditional Chinese medicines, hippophae rhamnoides, hypericum perforatum, and cacumen platycladi. Finally, rutin, kaempferol, quercetin, and quercetrin were discovered in these medicines and the concentrations ranged from 0.28 to 9.94 mg/g. The recoveries of flavonoids ranged from 84.7 to 113%, which showed the high reliability of this method. PMID:26829244

  19. Simultaneous Determination of Loratadine, Desloratadine and Cetirizine by Capillary Zone Electrophoresis

    PubMed Central

    Hancu, Gabriel; Campian, Camelia; Rusu, Aura; Mircia, Eleonora; Kelemen, Hajnal

    2014-01-01

    Purpose: The aim of the study was the development of a simple and rapid analytical procedure for the determination of the most frequently used antihistamine derivatives. Methods: A capillary zone electrophoretic method was developed for the simultaneous separation of loratadine, desloratadine and cetirizine. Efforts were focused primarly on the optimisation of the experimental parameters: buffer composition and concentration, buffer pH, applied voltage, temperature, injection pressure and time. Results: The optimised parameters for the separation were: 25 mM buffer electrolyte, buffer pH 2.5, voltage + 25 kV, temperature 25 °C, injection pressure 50 mbar, injection time 3 seconds, capillary 48 cm (effective length 40 cm) x 50 μm, detection at 240 nm. Under these conditions, the analysis time was below 5 minutes, the order of migration being: desloratadine, cetirizine and loratadine. The developed method was validated in terms of linearity, limits of detection and quantification, intra- and inter-day precision, selectivity and robustness. Conclusion: Capillary zone electrophoresis proved to be a suitable method for the simulatneous determination of the three studied antihistamine derivatives. PMID:24511480

  20. Separation of plant hormones from biofertilizer by capillary electrophoresis using a capillary coated dynamically with polycationic polymers.

    PubMed

    Jiang, Ting-Fu; Lv, Zhi-Hua; Wang, Yuan-Hong; Yue, Mei-E

    2006-06-01

    A new, simple and rapid capillary electrophoresis (CE) method, using hexadimethrine bromide (HDB) as electroosmotic flow (EOF) modifier, was developed for the identification and quantitative determination of four plant hormones, including gibberellin A3 (GA3), indole-3-acetic acid (IAA), alpha-naphthaleneacetic acid (NAA) and 4-chlorophenoxyacetic acid (4-CA). The optimum separation was achieved with 20 mM borate buffer at pH 10.00 containing 0.005% (w/v) of HDB. The applied voltage was -25 kV and the capillary temperature was kept constant at 25 degrees C. Salicylic acid was used as internal standard for quantification. The calibration dependencies exhibited good linearity within the ratios of the concentrations of standard samples and internal standard and the ratios of the peak areas of samples and internal standard. The correlation coefficients were from 0.9952 to 0.9997. The relative standard deviations of migration times and peak areas were < 1.93 and 6.84%, respectively. The effects of buffer pH, the concentration of HDB and the voltage on the resolution were studied systematically. By this method, the contents of plant hormone in biofertilizer were successfully determined within 7 min, with satisfactory repeatability and recovery. PMID:16772676

  1. Separation of plant hormones from biofertilizer by capillary electrophoresis using a capillary coated dynamically with polycationic polymers.

    PubMed

    Jiang, Ting-Fu; Lv, Zhi-Hua; Wang, Yuan-Hong; Yue, Mei-E

    2006-06-01

    A new, simple and rapid capillary electrophoresis (CE) method, using hexadimethrine bromide (HDB) as electroosmotic flow (EOF) modifier, was developed for the identification and quantitative determination of four plant hormones, including gibberellin A3 (GA3), indole-3-acetic acid (IAA), alpha-naphthaleneacetic acid (NAA) and 4-chlorophenoxyacetic acid (4-CA). The optimum separation was achieved with 20 mM borate buffer at pH 10.00 containing 0.005% (w/v) of HDB. The applied voltage was -25 kV and the capillary temperature was kept constant at 25 degrees C. Salicylic acid was used as internal standard for quantification. The calibration dependencies exhibited good linearity within the ratios of the concentrations of standard samples and internal standard and the ratios of the peak areas of samples and internal standard. The correlation coefficients were from 0.9952 to 0.9997. The relative standard deviations of migration times and peak areas were < 1.93 and 6.84%, respectively. The effects of buffer pH, the concentration of HDB and the voltage on the resolution were studied systematically. By this method, the contents of plant hormone in biofertilizer were successfully determined within 7 min, with satisfactory repeatability and recovery.

  2. Chiral separation of the plant lignan matairesinol by capillary electrophoresis.

    PubMed

    Müller, Ulrike; Mrestani, Yahya; Neubert, Reinhard; Dräger, Birgit

    2008-09-01

    Lignans are dimeric phenylpropanoid compounds in plants that enjoy increasing medicinal interest because of their phytoestrogen activity. Lignans are chiral compounds and for most natural occurring lignans, chirality is not known. Separation of racemic matairesinol by CE in a non-coated silica capillary with carboxymethyl-beta-cyclodextrin as chiral selector in phosphate buffer was successful. Electrolyte and selector concentrations and pH were systematically optimized in order to obtain baseline separation and short analysis times. Matairesinol from safflower fruit was determined as (-)-enantiomer. Quantitation results for matairesinol with the optimized method after calibration with authentic lignan were very similar to those by HPLC. The limit of detection is 2 microg/mL sample by DAD detection. PMID:18803219

  3. Development and Validation of a Stability-Indicating Capillary Electrophoresis Method for the Determination of Zolpidem Tartrate in Tablet Dosage Form with Positive Confirmation using 2D- and 3D-DAD Fingerprints

    PubMed Central

    Al Azzam, Khaldun M.; Yit, Lee Kam; Saad, Bahruddin; Shaibah, Hassan

    2014-01-01

    The aim of the current study was to develop a simple, precise, and accurate capillary zone electrophoresis method for the determination of zolpidem tartrate in tablet dosage form. Separation was conducted in normal polarity mode at 25°C, 22 kV, using hydrodynamic injection for 10 s. Separation was achieved using a background electrolyte of 20 mM disodium hydrogen phosphate adjusted with phosphoric acid (85%), pH at 5.50, and detection at 254 nm. Using the above optimized conditions, complete determination took place in less than 3 min using amiloride HCl as the internal standard. The method was linear over the range of 3–1000 μg mL−1 with a correlation coefficient of 0.9999. Forced degradation studies were conducted by introducing a sample of zolpidem tartrate standard and pharmaceutical sample solutions to different forced degradation conditions, being neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H2O2), temperature (60°C in oven for 3 days), and photolytic (exposure to UV light at 254 nm for 2 h). Degradation products resulting from the stress studies did not interfere with the detection of zolpidem tartrate and the assay can be considered stability-indicating. PMID:24959406

  4. Determination of impurities in heparin by capillary electrophoresis using high molarity phosphate buffers.

    PubMed

    Wielgos, Todd; Havel, Karalyn; Ivanova, Nadia; Weinberger, Robert

    2009-02-20

    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%.

  5. Quantitative Determination of Lercanidipine Enantiomers in Commercial Formulations by Capillary Electrophoresis

    PubMed Central

    Lourenço, Luciana Pereira; Aguiar, Fernando Armani; de Oliveira, Anderson Rodrigo Moraes; de Gaitani, Cristiane Masetto

    2015-01-01

    An enantioselective method based on capillary electrophoresis (CE) using cyclodextrin (CD) as chiral selector was developed and validated for determination of lercanidipine (LER) enantiomers, a drug calcium channel blocker which exerts antihypertensive effects of long duration, in a pharmaceutical formulation. Optimum separation of LER enantiomers was obtained on a 50 cm × 50 μm id capillary using a sodium acetate buffer solution 200 mmol/L pH 4.0 containing 10 mmol/L of 2,3,6-o-methyl-β-cyclodextrin (TM-β-CD) as background electrolyte. The capillary temperature and voltage were 15°C and 25 kV, respectively, hydrodynamic injection and detection at 237 nm. Linearity was obtained in the range 12.5–100 μg/mL for both enantiomers (r ≥ 0.995). The RSD (%) and relative errors (E, %) obtained in precision and accuracy studies (intraday and interday) were lower than 5%. After validation, the method was applied to quantify the enantiomers of LER in commercial tablets and the results were satisfactory in terms of accuracy and precision, both less than 5%. Therefore, this method was found to be appropriate for enantioselective quality control of LER enantiomers in pharmaceutical formulations. PMID:25821632

  6. Characterization of a post-column reaction-laser-induced fluorescence detector for capillary zone electrophoresis.

    PubMed

    Nickerson, B; Jorgenson, J W

    1989-10-20

    Several modifications have been made to a post-column labeling system for use with capillary zone electrophoresis. Fluorescence excitation is now performed with a helium-cadmium laser rather than an arc lamp. The focusability of the laser beam allows the use of larger diameter capillaries in the post-column reactor without the excessive band broadening observed previously. These larger capillaries can be assembled in the reactor much more easily. Another improvement is that the flow-rate of the labeling reagent can now be accurately controlled and determined. Incorporating these changes, the performances of two reactors with capillaries of the same dimensions are compared.

  7. Novel Instrument for Automated pK(a) Determination by Internal Standard Capillary Electrophoresis.

    PubMed

    Cabot, Joan M; Fuguet, Elisabet; Rosés, Martí; Smejkal, Petr; Breadmore, Michael C

    2015-06-16

    The internal standard capillary electrophoresis method (IS-CE) has been implemented in a novel sequential injection-capillary electrophoresis instrument for the high-throughput determination of acidity constants (pK(a)) regardless of aqueous solubility, number of pK(a) values, or structure. This instrument comprises a buffer creation system that automatically mixes within a few seconds four reagents for in situ creation of the separation electrolyte with a pH range of 2-13, ionic strength of 10-100 mM and organic solvent content from 0% to 40%. Combined with 1.2 kV/cm and a short effective length (15 cm to the UV detector) fast 20 s electrophoretic separations can be obtained. The low standard deviation of the replicates and the low variation compared to reference values show that this system can accurately determine acidity constants of drugs by IS-CE. A single pK(a) can be determined in 2 min and a set of 20 measurements in half an hour, allowing rapid, simple, and flexible determination of pK(a) values of pharmaceutical targets.

  8. Determination of biogenic amines by capillary electrophoresis with pulsed amperometric detection.

    PubMed

    Sun, Xiuhua; Yang, Xiurong; Wang, Erkang

    2003-07-11

    The biogenic amines, putrescine, cadaverine, spermidine and spermine were separated and quantified by capillary electrophoresis with pulsed amperometric detection. Detection potential of the pulsed amperometric detection was optimized as 0.6 V. Optimal separation of the biogenic amines was achieved using a separation buffer of 30 mM citrate at pH 3.5, while keeping the buffer in the detection cell as 20 mM NaOH. Using these conditions, the four biogenic amines were baseline separated. Extrapolated limits of detection for putrescine, cadaverine, spermidine and spermine were 400, 200, 100 and 400 nM for the standard mixture (polyamines dissolved in running buffer), respectively. These are lower than ultraviolet detection and comparable or even lower than laser-induced fluorescence detection results as reported in the literature. The number of theoretical plates was maintained at the 10(5) level, which is absolutely higher than any reported method. When applying capillary electrophoresis-pulsed amperometric detection to milk analysis, only spermidine was found in amounts varying between 0.1 and 0.5 mg/kg.

  9. ANALYSIS OF GLYCANS DERIVED FROM GLYCOCONJUGATES BY CAPILLARY ELECTROPHORESIS-MASS SPECTROMETRY

    PubMed Central

    Mechref, Yehia

    2012-01-01

    The high structural variation of glycan derived from glycoconjugates, which substantially increases with the molecular size of a protein, contributes to the complexity of glycosylation patterns commonly associated with glycoconjugates. In the case of glycoproteins, such variation originates from the multiple glycosylation sites of proteins and the number of glycan structures associated with each site (microheterogeneity). The ability to comprehensively characterize highly complex mixture of glycans has been analytically stimulating and challenging. Although the most powerful mass spectrometric (MS) and tandem MS techniques are capable of providing a wealth of structural information, they are still not able to readily identify isomeric glycan structures without high order tandem MS (MSn). The analysis of isomeric glycan structures has been attained using several separation methods, including high-pH anion exchange chromatography (HPAEC), hydrophilic interaction chromatography (HILIC) and gas chromatography (GC). However, capillary electrophoresis (CE) and microfluidics capillary electrophoresis (MCE) offer high separation efficiency and resolutions, allowing the separation of closely related glycan structures. Therefore, interfacing CE and MCE to MS is a powerful analytical approach, allowing potentially comprehensive and sensitive analysis of complex glycan samples. This review describes and discusses the utility of different CE and MCE approaches in the structural characterization of glycoproteins and the feasibility of interfacing these approaches to mass spectrometry. PMID:22180203

  10. Isolation of flavonoids from Delonix elata and determination of its rutin content using capillary electrophoresis.

    PubMed

    Al-Taweel, Areej Mohammed; Abdel-Kader, Maged Saad; Fawzy, Ghada Ahmed; Perveen, Shagufta; Maher, Hadir Mohamed; Al-Zoman, Nourah Zoman; Al-Shehri, Mona Mohamed; Al-Johar, Haya; Al-Showiman, Hessa

    2015-09-01

    Delonix elata (L.) Gamble (Fabaceae) is an important, traditionally used plant in Saudi Arabia. It is used to relieve rheumatic pain, flatulence and the seeds are employed as purgatives. The aim of the present study was to isolate chemical constituents of the n-butanol fraction (BF) of D. elata and to find out, by capillary electrophoresis (CE), percentage of rutin present in this BF. Three quercetin glycosides and one kaempferol rutinoside were isolated from the BF of aerial parts of D. elata; namely, Quercetin 3-O-rutinoside-7-O-glucoside (1), Quercetin 3,7-diglucoside (2), Quercetin 3-O-rutinoside (RUT) (3) and Kaempferol 3-O-rutinoside (4). Rutin, an active constituent has been reported to possess good pharmacological as well as therapeutic potentials. A sensitive and rapid procedure for quantitative determination of RUT by capillary electrophoresis was developed and its content was found to be 7.349 mg/gm, relative to n-butanol fraction and 18.373 mg%, relative to the dry powder of D. elata. The method could be recommended for approval and use in the pharmaceutical and food industries. PMID:26525033

  11. Determination of biogenic amines in beer and wine by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Daniel, Daniela; Dos Santos, Vagner Bezerra; Vidal, Denis Tadeu Rajh; do Lago, Claudimir Lucio

    2015-10-16

    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.

  12. Separation and determination of pseudoephedrine, dextromethorphan, diphenhydramine and chlorpheniramine in cold medicines by nonaqueous capillary electrophoresis.

    PubMed

    Dong, Yuming; Chen, Xiaofeng; Chen, Yonglei; Chen, Xingguo; Hu, Zhide

    2005-09-01

    An easy, rapid and simple nonaqueous capillary electrophoresis (NACE) method was developed for the identification and determination of four basic nitrogenous compounds, i.e. pseudoephedrine (PE), dextromethorphan (DXM), diphenhydramine (DHM) and chlorpheniramine (CLP). The most suitable running buffer was composed of 40 mM ammonium acetate, 10% acetonitrile (ACN) in methanol with a fused-silica capillary column (47 cm x 75 microm i.d.), 25 kV applied voltage and 25 degrees C capillary temperature. The calibration curves revealed linear relationships between the peak area for each analyte and its concentration (correlation coefficients: 0.9993 for PE, 0.9971 for DXM, 0.9991 for DHM, and 0.9995 for CLP, respectively). The relative standard deviations of the migration time and peak area of the four compounds were 0.37, 3.90, 0.73 and 0.68, and 2.80, 3.50, 1.60 and 3.70%, respectively. The method was successfully applied to determine the four compounds in five cold medicines, the recoveries of the four constituents ranging between 91 and 109%.

  13. Single molecule fluorescence burst detection of DNA separated by capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Haab, Brian B.; Mathies, Richard A.

    1996-03-01

    A method has been developed for detecting DNA separated by capillary gel electrophoresis using single molecule photon burst counting. A confocal fluorescence microscope was used to observe the fluorescence bursts from single molecules of DNA multiply labeled with a thiazole orange derivative as they passed through the approximately 2 micrometer diameter focused laser beam. Amplified photoelectron pulses from the photomultiplier are grouped into bins of from 360 - 450 microseconds in duration, and the resulting histogram stored in a computer for analysis. Solutions of M13 DNA were first flowed through the capillary at various concentrations, and the resulting data were used to optimize the parameters for digital filtering using a low-pass Fourier filter, selecting a discriminator level for peak detection, and applying a peak-calling algorithm. The optimized single molecule counting method was then used to detect a separation of pBR 322 DNA from pRL 277 DNA. Clusters of discrete fluorescence bursts were observed at the expected appearance time of each DNA band. These separations were easily detected when only 50 to 100 molecules of DNA per band traveled through the detection region. This new detection technology should lead to the routine analysis of DNA in capillary columns with an on-column sensitivity of approximately 100 DNA molecules per band or better.

  14. Determination of biogenic amines in beer and wine by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Daniel, Daniela; Dos Santos, Vagner Bezerra; Vidal, Denis Tadeu Rajh; do Lago, Claudimir Lucio

    2015-10-16

    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. PMID:26362807

  15. [A Detection of Allelic Variants at Microsatellite Markers by Using Capillary and Traditional Electrophoresis].

    PubMed

    Rubtsova, G A; Ponomareva, E V; Afanasiev, K I; Shaikhaev, E G; Kholodova, M V; Pavlov, S D; Zhivotovsky, L A

    2016-04-01

    Microsatellite alleles are detected by PCR (polymerase chain reaction) that provides a manifold increase in the number of copies (amplification) of a given DNA fragment. The fragment visualization can be reached by two different methods. These are fragment analysis by capillary electrophoresis in denaturing gel and frag- ment separation in non-denaturing gel with subsequent gel staining. The first method is more accurate and automated, but expensive. The second method is much cheaper but less convenient. It requires manual pro- cessing and is presumably less accurate. In this study, we present the results of comparison of the allele typing at nine microsatellite loci using these two methods for one of the species of Pacific salmon, sockeye salmon Oncorhynchus nerka Walbaum. In most cases, both methods give identical fragment sizes or a constant differ- ence if the alleles are relatively small (not larger than 200-220 bp). PMID:27529983

  16. Monitoring antigenic protein integrity during glycoconjugate vaccine synthesis using capillary electrophoresis-mass spectrometry.

    PubMed

    Tengattini, Sara; Domínguez-Vega, Elena; Temporini, Caterina; Terreni, Marco; Somsen, Govert W

    2016-09-01

    A capillary electrophoresis-mass spectrometry (CE-MS) method was developed for the characterization and integrity assessment of the Mycobacterium tuberculosis (MTB) antigens TB10.4 and Ag85B and their chemically produced glycoconjugates, which are glycovaccine candidates against tuberculosis (TB). In order to prevent protein adsorption to the inner capillary wall and to achieve efficient separation of the antigen proteoforms, a polyionic multilayer coating of polybrene-dextran sulfate-polybrene (PB-DS-PB) was used in combination with 1.5 M acetic acid as background electrolyte (BGE). Coupling of CE to high-resolution time-of-flight MS was achieved by a coaxial interface employing a sheath liquid of isopropanol-water (50:50, v/v) containing 0.1 % formic acid. The MTB antigens were exposed to experimental conditions used for chemical glycosylation (but no activated saccharide was added) in order to investigate their stability during glycovaccine production. CE-MS analysis revealed the presence of several closely related degradation products, including truncated, oxidized and conformational variants, which were assigned by accurate mass. Analysis of synthesized mannose conjugates of TB10.4 and Ag85B allowed the determination of the glycoform composition of the neo-glycoproteins next to the characterization of degradation products which were shown to be partly glycoconjugated. Moreover, the selectivity of CE-MS allowed specific detection of deamidated species (protein mass change of 1.0 Da only), indicating that chemical glycosylation increased susceptibility to deamidation. Overall, the results show that CE-MS represents a useful analytical tool for the detailed characterization and optimization of neo-glycoconjugate products. Graphical Abstract Flowchart illustrating Mycobacterium tuberculosis (MTB) antigen glycosylation, glycoconjugate variant and degradation product separation by capillary electrophoresis (CE) and their characterization by intact mass

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

    SciTech Connect

    Lu, X.

    1998-03-27

    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. Capillary electrophoresis of DNA from Cannabis sativa for correlation of samples to geographic origin.

    PubMed

    Coyle, Heather Miller

    2012-01-01

    For routine genetic analysis of Cannabis sativa, two methods are currently in use, (a) AFLP; amplified fragment length polymorphism analysis and (b) STR; short tandem repeat analysis. The AFLP method used on capillary electrophoresis instrumentation is fully described in this chapter. AFLP analysis generates numerous nonspecific marker fragments for a complex DNA pattern and is available in kit format for quality assurance of reagents. This method is particularly useful when discerning the genetics of highly inbred plant species that may share much of the same DNA with only slight differences due to their common genetic background. AFLP analysis, however, is most effective on fresh or well-preserved plant specimens where the integrity of the DNA is high and the sample is a single source specimen (i.e., not a mixture of plants or different species). PMID:22139665

  19. Evaluation of capillary electrophoresis for in-flight ionic contaminant monitoring of SSF potable water

    NASA Technical Reports Server (NTRS)

    Mudgett, Paul D.; Schultz, John R.; Sauer, Richard L.

    1992-01-01

    Until 1989, ion chromatography (IC) was the baseline technology selected for the Specific Ion Analyzer, an in-flight inorganic water quality monitor being designed for Space Station Freedom. Recent developments in capillary electrophoresis (CE) may offer significant savings of consumables, power consumption, and weight/volume allocation, relative to IC technology. A thorough evaluation of CE's analytical capability, however, is necessary before one of the two techniques is chosen. Unfortunately, analytical methods currently available for inorganic CE are unproven for NASA's target list of anions and cations. Thus, CE electrolyte chemistry and methods to measure the target contaminants must be first identified and optimized. This paper reports the status of a study to evaluate CE's capability with regard to inorganic and carboxylate anions, alkali and alkaline earth cations, and transition metal cations. Preliminary results indicate that CE has an impressive selectivity and trace sensitivity, although considerable methods development remains to be performed.

  20. Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection.

    PubMed

    Wu, Xiaomu; Gong, Suxuan; Bo, Tao; Liao, Yiping; Liu, Huwei

    2004-12-24

    In this article, the dissociation constants (pKa) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pKa values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pKa values (pKa1 and pKa2) were found for four xanthones while generally the 10 compounds possess the pKa values ranging from 6.4 to 9.2. PMID:15641365

  1. Micellar electrokinetic capillary electrophoresis for rapid analysis of patulin in apple cider.

    PubMed

    Tsao, R; Zhou, T

    2000-11-01

    A micellar electrokinetic capillary chromatography (MECC) mode was applied to a capillary electrophoresis (CE) method, which was developed for detection and quantitation of patulin in apple ciders. This method used a small sample amount (2 mL) and consumed minimal organic solvent compared to the most commonly used HPLC methods. The sample preparation procedure of the CE method was also simpler than other chromatographic techniques developed for patulin analysis. Patulin was detected with a photodiode array detector at 273 nm. The standard curve was linear (r(2) = 0.9984) from 75 microgram/L to 121 microgram/mL with patulin working solutions corresponding to 3.8 microgram/L to 6.1 microgram/mL patulin in the sample. The linearity was better in a narrower range of concentrations (r(2) = 0.9999) from 75 microgram/L to 24.1 microgram/mL. The limit of detection of the method was 3.8 microgram/L. Patulin recoveries at 4 levels in spiked samples (10-121 microgram/L) ranged from 95.2 to 105.4%. The recoveries were 96. 9% and 99.2% for 2 levels (22.3 and 223 microgram/L, respectively) of patulin in infected apple samples. This method represents a unique alternative method for rapid and sensitive analysis of patulin in apple ciders. PMID:11087465

  2. Self-assembled covalent capillary coating of diazoresin/carboxyl fullerene for analysis of proteins by capillary electrophoresis and a comparison with diazoresin/graphene oxide coating.

    PubMed

    Yu, Bing; Shu, Xi; Cong, Hailin; Chen, Xin; Liu, Huwei; Yuan, Hua; Chi, Ming

    2016-03-11

    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.

  3. New advances in on-line sample preconcentration by capillary electrophoresis using dynamic pH junction.

    PubMed

    Ptolemy, Adam S; Britz-McKibbin, Philip

    2008-12-01

    The small injection volumes and narrow dimensions characteristic of microseparation techniques place constraints on concentration sensitivity that is required for trace chemical analyses. On-line sample preconcentration techniques using dynamic pH junction and its variants have emerged as simple yet effective strategies for enhancing concentration sensitivity of weakly ionic species by capillary electrophoresis (CE). Dynamic pH junction offers a convenient format for electrokinetic focusing of dilute sample plugs directly in-capillary for improved detection without off-line sample pretreatment. In this report, we highlight new advances in dynamic pH junction which have been reported to enhance method performance while discussing challenges for future research.

  4. Nonaqueous capillary electrophoresis of imatinib mesylate and related substances.

    PubMed

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

    2012-08-01

    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.

  5. Fluid mechanics of electroosmotic flow and its effect on band broadening in capillary electrophoresis.

    PubMed

    Ghosal, Sandip

    2004-01-01

    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.

  6. High-Throughput Genetic Analysis and Combinatorial Chiral Separations Based on Capillary Electrophoresis

    SciTech Connect

    Wenwan Zhong

    2003-08-05

    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.

  7. Design and operation of a portable scanner for high performance microchip capillary array electrophoresis.

    PubMed

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

    2010-11-01

    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.

  8. Design and operation of a portable scanner for high performance microchip capillary array electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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.

  9. Buffer additives other than the surfactant sodium dodecyl sulfate for protein separations by capillary electrophoresis.

    PubMed

    Corradini, D

    1997-10-10

    The different compounds utilized as additives to the electrolyte solutions employed in protein capillary zone electrophoresis (CZE) for minimizing protein-capillary wall interactions, for improving selectivity and resolution and for controlling the electroosmotic flow are reviewed. The dependence of the electroosmotic flow on the different variables that can be affected by the incorporation of an additive into the electrolytic solution is discussed. A list of the most effective additives employed for protein separations by CZE is reported in Appendix A.

  10. Steroid determination in fish plasma using capillary electrophoresis

    USGS Publications Warehouse

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

    2010-01-01

    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.

  11. Application of capillary electrophoresis to the measurement of oligonucleotide concentration and purity over a wide dynamic range.

    PubMed

    Lowery, J D; Ugozzoli, L; Wallace, R B

    1997-12-15

    Synthetic oligonucleotides rarely contain 100% of the full-length sequence due, in part, to the failure sequences produced during synthesis. In this paper, a method is described for the determination of both the concentration and the purity of oligonucleotides, utilizing capillary electrophoresis with a deoxyribo-nucleoside triphosphate as an internal standard. This method is advantageous for several reasons: (a) the wide dynamic range allows for the analysis of samples without the need for dilutions; (b) a small sample size is used for analysis; (c) capillary electrophoresis is automatable which allows for high throughput; and (d) all of the samples are analyzed at the same run temperature which aids in reproducibility and consistency between runs performed at different times.

  12. Determination of aminoglycoside antibiotics in pharmaceuticals by capillary zone electrophoresis with indirect UV detection coupled with micellar electrokinetic capillary chromatography.

    PubMed

    Ackermans, M T; Everaerts, F M; Beckers, J L

    1992-08-14

    Aminoglycoside antibiotics can be determined by capillary zone electrophoresis (CZE) with indirect UV detection in the anionic mode with a reversed electroosmotic flow (EOF) by addition of FC 135 to the background electrolyte. The effective mobilities of thirteen aminoglycoside antibiotics were determined as a function of pH. Applying CZE with indirect UV detection in the anionic mode and reversed EOF coupled with micellar electrokinetic capillary chromatography with the cationic surfactant cetyltrimethylammonium bromide, both neutral and charged antibiotics can be determined in combined pharmaceuticals. As an example, neomycin and hydrocortisone were determined in Otosporin eardrops.

  13. Quantitative enantiomeric analysis of chlorcyclizine, hydroxyzine, and meclizine by capillary electrophoresis.

    PubMed

    Ho, Yu- Hsiang; Wu, Hsin- Lung; Wu, Shou- Mei; Chen, Su- Hwei; Kou, Hwang- Shang

    2003-07-01

    A simple capillary zone electrophoresis method was developed for the quantitative enantiomeric analysis of piperazine antihistamines with teratogenic suspicion in animals. Enantioseparation of chlorcyclizine, hydroxyzine, and meclizine was performed in glycine buffer (0.6 mol L(-1); pH 3.00) with sulfated beta-cyclodextrin (5 mg mL(-1)) as a chiral selector; and the separated drugs were monitored by ultra-violet detector. The lower quantitation of the individual enantiomer is attainable at 10 micro mol L(-1), using an achiral piperazine drug (cyclizine) as internal standard. The method is simple and rapid with a short run time (<5 min) for the analysis of chlorcyclizine, hydroxyzine or meclizine enantiomers. PMID:12830360

  14. Using Capillary Electrophoresis to Determine the Purity of Acetylsalicylic Acid Synthesized in the Undergraduate Laboratory

    NASA Astrophysics Data System (ADS)

    Welder, Frank; Colyer, Christa L.

    2001-11-01

    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.

  15. Integration of rapid DNA hybridization and capillary zone electrophoresis using bidirectional isotachophoresis.

    PubMed

    Bahga, Supreet S; Han, Crystal M; Santiago, Juan G

    2013-01-01

    We present a method for rapid, sequence-specific detection of multiple DNA fragments by integrating isotachophoresis (ITP) based DNA hybridization and capillary zone electrophoresis (CZE) using bidirectional ITP. Our method leverages the high preconcentration ability of ITP to accelerate slow, second-order DNA hybridization kinetics, and the high resolving power of CZE to separate and identify reaction products. We demonstrate the speed and sensitivity of our assay by detecting 5 pM, 39 nt ssDNA target within 3 min, using a molecular beacon probe. We also demonstrate the feasibility of our assay for multiplexed detection of multiple-length ssDNA targets by simultaneously detecting 39 and 90 nt ssDNA targets.

  16. Determination of phenolic disinfectants in consumer products by capillary electrophoresis with amperometric detection.

    PubMed

    Jiang, Lianmei; Wang, Jinyan; He, Yan; Ye, Jiannong; Chu, Qingcui

    2010-08-01

    Numerous disinfection products are widely used in daily life to kill pathogenic microorganisms. However, most disinfectants are organic compounds that might be hazardous to the environment and humans when used excessively. Phenolic disinfectants in disinfection products are investigated using a high-performance capillary electrophoresis-amperometric detection method. Under the optimum conditions, five commonly used disinfectants can be well-separated within 19 min at the separation voltage of 18 kV in a 80 mmol/L borax running buffer (pH 9.2), and adequate extraction was obtained with ethanol for the determination of the five compounds. Satisfactory recovery (93.5-106.0%), intra-day repeatability of the peak current (< 2.9%), and detection limits (1.6 x 10(-7) - 3.8 x 10(-8) g/mL) for the method are achieved. This proposed procedure is successfully used to analyze different samples of disinfection products.

  17. Effects of nebulizing and drying gas flow on capillary electrophoresis/mass spectrometry.

    PubMed

    Huikko, Katri; Kotiaho, Tapio; Kostiainen, Risto

    2002-01-01

    This study was focused on examining the influence of gas flow parameters on capillary electrophoresis/mass spectrometry (CE /MS) performance using sheath-liquid CE /MS interfaces. The effects of nebulizing and drying gas velocity and drying gas temperature on CE separation and MS detection sensitivity were systematically determined. Nebulizing gas velocity was observed to be a critical parameter in the optimization of CE /MS method, since it affected both MS detection sensitivity, and also CE separation efficiency for one interface design tested. Better detection sensitivity was obtained when the nebulizing gas velocity was increased. However, high velocity of the nebulizing gas flow can cause a hydrodynamic bulk flow inside the CE capillary, thus clearly increasing the apparent mobility and decreasing the resolution obtained for the compounds studied. Increasing the drying gas velocity or temperature did not affect the apparent mobility or the separation efficiency and the temperature could be increased to achieve the optimal detection sensitivity in the CE /MS analysis. For comparison, the effects of nebulizing gas flow were studied using a different design of the coaxial sheath-liquid CE /MS interface, and in this case better detection sensitivity but no effect on CE separation efficiency was observed with increased nebulizing gas velocity. These different effects of nebulizing gas flow on the CE bulk flow were concluded to result from pressure differences at the tip of the CE capillaries for the different CE /MS interface arrangements. It is therefore recommended that the cross-sectional dimensions of the fused-silica and steel capillaries, and the gas streamlines, should be optimized when CE /MS interfaces are built. Moreover, the effect of gas flow on CE separation should be studied when optimizing the CE /MS operation parameters.

  18. Simultaneous determination of naphazoline, diphenhydramine and phenylephrine in nasal solutions by capillary electrophoresis.

    PubMed

    Marchesini, A F; Williner, M R; Mantovani, V E; Robles, J C; Goicoechea, H C

    2003-02-01

    A capillary zone electrophoresis (CZE) method has been developed to separate and quantitate naphazoline (NAPH), dyphenhydramine (DIP) and phenylephrine (PHE) in nasal solutions. Samples were diluted 1:25 in ultrapure water and injected at the anodic end. A central composite design has been used to optimise the experimental conditions for a complete and fast separation of the active ingredients studied. Critical parameters such as voltage, pH and buffer concentration have been studied to evaluate how they affect responses such as resolution and migration times. Separation was performed on a silica capillary with 75 microm I.D. and 70 cm total length at an applied voltage of 17.7 kV with a phosphate run buffer of pH 3.72 and 0.063 mol l(-1). Calibration curves were prepared for NAPH, DIP and PHE. For each analyte, the correlation coefficients were >0.999 (n=15). The RSD% of six replicate injections for each analyte were reasonably good. The method was applied to the quantitation of the three components in a commercial dosage form. The proposed method has the advantage of needing a very simple sample pretreatment and being faster than a typical HPLC chromatographic method.

  19. Investigation of capillary free-flow electrophoresis for separation of Co, Cr, and As species in aqueous solution

    SciTech Connect

    Ketterer, M.E.; Kozerski, G.E.; Ritacco, R.; Painuly, P.

    1997-01-01

    Application of a prototype capillary free-flow electrophoresis (CFFE) device for separation of different solution species of Co, Cr, and As is explored. A unique free-flow electrophoresis (FFE) design is employed, which makes use of internal capillary cooling tubes to minimize thermal convection due to Joule heating.

  20. Reliable low-cost capillary electrophoresis device for drug quality control and counterfeit medicines.

    PubMed

    Marini, R D; Rozet, E; Montes, M L A; Rohrbasser, C; Roht, S; Rhème, D; Bonnabry, P; Schappler, J; Veuthey, J-L; Hubert, Ph; Rudaz, S

    2010-12-15

    The proportion of counterfeit medicines is dramatically increasing these last few years. According to numerous official sources, in some pharmaceutical wholesalers in African countries, the proportion has reached 80%. Unfortunately, this situation is far to be improved due to lack of suitable analytical equipment allowing rapid actions of the Regulatory Agencies based on scientific consideration, at affordable cost and all over the drug supply chain. For that purpose, a network group considered that mater by building a low-cost original capillary electrophoresis (CE) equipment equipped with a new deep UV detector based on LED technology. The generic conditions for analysis were investigated: capillary zone electrophoresis (CZE) performed at acidic pH for basic drug molecules (i.e., quinine, highly used as the last antimalarial rampart), basic pH for compounds such as furosemide (a common diuretic drug) and at neutral pH for a well known antibiotic combination, trimethoprim/sulfamethoxazol. To evaluate the ability of the CE equipment for quantification, a full validation and a method comparison study were carried out for the CZE method dedicated to quinine determination. The validation involved the use of accuracy profile and total error concept to monitor the adequacy of the results obtained by the new prototype. The method comparison was based on the Bland and Altman approach by comparing results obtained by the low-cost CE and a conventional set-up. Subsequent validation studies were realized with neutral and acidic drug molecules, each focusing on a single concentration level calibration curve in order to maintain as low as possible the expenses due to reagents and thus the cost of analysis, as important advantages of CE for drug quality control. PMID:20719445

  1. Application of capillary electrophoresis with electrokinetic supercharging and sweeping for the on-line preconcentration of phenolic acids.

    PubMed

    Lin, Yi-Hui; Huang, Hsin-Chieh; Hsu, Wan-Ling

    2015-09-01

    Phenolic acids are natural antioxidants. Many studies have confirmed that these compounds can reduce the risk of developing chronic diseases such as diabetes, cardiovascular diseases, and certain cancers. In this work, we developed a rapid and efficient capillary electrophoresis method with an on-line preconcentration technique that could be used to simultaneously analyze 10 commonly found phenolic acids in plants. Briefly, phosphate buffer solution (pH 2) was filled into an uncoated fused silica capillary as the leading electrolyte, and then samples which were prepared in borate buffer (as the terminating ion) were loaded by electrokinetic injection (-10 kV, 900 s). After sample injection, both ends of the capillary were switched to the vial containing phosphate buffer with sodium dodecyl sulfate. The separation was then performed in micellar electrokinetic chromatography (MEKC) mode at -20 kV. During the method validation, the correlation coefficient of the regression curve was measured as greater than 0.997 and the relative standard deviation and relative error were lower than 9.63 % and 4.7 %, respectively. The limits of detection (LODs, S/N = 3) of these 10 analytes ranged from 0.01 to 2.5 ng/mL. Compared with the conventional capillary zone electrophoresis (CZE) method, the sensitivity for the analytes could be increased up to 25,000-fold. The method that we developed here was applied successfully to the detection of phenolic acids in fruit juices. PMID:26159571

  2. Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis.

    PubMed

    Chang, Po-Ling; Hsieh, Ming-Mu; Chiu, Tai-Chia

    2016-04-01

    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.

  3. [Stereoselective analysis of pharmaceutical compounds in biological fluids with capillary electrophoresis].

    PubMed

    Desiderio, C; Fanali, S

    1995-11-01

    Biological fluids drugs analysis are important to investigate the pharmacokinetic and pharmacodynamic of the subministered compounds for the comprehension of their behaviour and bioavailability. Many pharmaceutical preparations contain a chiral molecule as active compound often as racemic mixture of the two enantiomers of which only one exhibits pharmacological effect, the other enantiomer being inactive or responsible of toxicological effects. In fact two enantiomers with almost identical physical and chemical properties can exhibit a different behaviour in an highly stereoselective environment as the human body. With respect to the analytical methods in use for chiral separation Capillary Electrophoresis shows high efficiency and resolution together with feasibility, low costs and very short analysis time. CE and MEKC have been used for enantiomers resolution of antihypertensive and anticoagulant drugs in body fluids. By cyclodextrin modified MECK the separation of mephenytoin and 4-hydroxymephenytoin metabolite in urine samples has been performed in order to identify different phenotypes in the oxidative metabolising ability in man.

  4. Simultaneous determination of multiple constituents in real beer samples of different origins by capillary zone electrophoresis.

    PubMed

    Cortacero-Ramírez, Sonia; Segura-Carretero, Antonio; Cruces-Blanco, Carmen; Romero-Romero, Maria Luisa; Fernández-Gutiérrez, Alberto

    2004-11-01

    Simultaneous determination of alcohols, amines, amino acids, flavonoids, and purine and pyrimidine bases in bottled beer samples directly without any pre-treatment was carried out by capillary zone electrophoresis with diode-array detection. Electrolyte conditions such as pH, composition and concentration of the buffer, working voltage and type and time of injection were checked. The best separation of the cited analytes was achieved in 70 mM sodium borate solution and pH 10.25. The detection limits were from 2.1 to 5.6 mg L(-1) for the 18 compounds studied. The developed method is rapid, sensitive and quantitative and has been applied to seven types of international bottled beers of different origins bought locally. PMID:15490130

  5. [Valuation of absorption of organic compounds in human body using liposome capillary electrophoresis].

    PubMed

    Zou, Xiaobing; Jiang, Honggui; Dong, Zhiqiang; Xia, Zhining; Jiang, Xuemei

    2008-11-01

    Liposome capillary electrophoresis (LCE) was used as a model for the in vitro evaluation of the degree of membrane penetration of organic compounds. The hydrophobic parameters of 9 compounds were determined by LCE. In comparison of the correlation coefficient of log P(lw) (the logarithm of the partition coefficient of liposome/water system, calculated from retention factor) vs. log P(m) (the logarithm of osmotic coefficient) with that of log P(ow) (the logarithm of the partition coefficient of octanol/water system) vs. log P(m), the former was 0.94, much greater than the latter 0.78. It means that as the biomembrane model, liposome is more similar than the octanol/water system. The LCE method has the potential to be an in vitro screening model.

  6. Ultrafast capillary electrophoresis isolation of DNA aptamer for the PCR amplification-based small analyte sensing

    PubMed Central

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

    2015-01-01

    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 (CE) and the sensitivity of real time PCR amplification. An ultrafast isolation of target-bound split aptamer (60 s) was developed by designing a CE input/ouput scheme. Such method was successfully applied to the determination of adenosine with a LOD of 1 μM. PMID:26322305

  7. Ultrafast capillary electrophoresis isolation of DNA aptamer for the PCR amplification-based small analyte sensing.

    PubMed

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

    2015-01-01

    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 (CE) and the sensitivity of real time PCR amplification. An ultrafast isolation of target-bound split aptamer (60 s) was developed by designing a CE input/ouput scheme. Such method was successfully applied to the determination of adenosine with a LOD of 1 μM.

  8. Capillary electrophoresis as a tool for the characterization of pentosan nanoparticles.

    PubMed

    Abdel-Haq, Hanin; Bossù, Elena

    2012-09-28

    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.

  9. Analysis of Soft Drinks: UV Spectrophotometry, Liquid Chromatography, and Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    McDevitt, Valerie L.; Rodriguez, Alejandra; Williams, Kathryn R.

    1998-05-01

    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.

  10. Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis

    PubMed Central

    Chang, Po-Ling; Hsieh, Ming-Mu; Chiu, Tai-Chia

    2016-01-01

    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. PMID:27070634

  11. Research on flavonoids contents in Fructus sophorae with capillary zone electrophoresis.

    PubMed

    Shi, Qiang; Sui, Lu-zhi; Lu, Yuan-qi

    2013-11-01

    Genistin, genistein, kaempferol, quercetin and rutin, five kinds of flavonoids in Fructus sophorae, have been analyzed by capillary zone electrophoresis with internal standard calibration. Buffer pH and concentration, applied voltage, β-cyclodextrin and ethanol concentration were optimized and the optimum conditions are: 20 mmol/L borax (pH 9.5) with 8 mmol/L β-cyclodextrin and 5% (v/v) ethanol and at a voltage of 25 kV. The contents of five flavonoids in Fructus Sophorae grown in different area of Dezhou, Shandong Province of China were determined by the developed method and with satisfactory results. The distributions of the studied flavonoids were also investigated. PMID:24191317

  12. Typing of 49 autosomal SNPs by single base extension and capillary electrophoresis for forensic genetic testing.

    PubMed

    Børsting, Claus; Tomas, Carmen; Morling, Niels

    2012-01-01

    We describe a method for simultaneous amplification of 49 autosomal single nucleotide polymorphisms (SNPs) by multiplex PCR and detection of the SNP alleles by single base extension (SBE) and capillary electrophoresis. All the SNPs may be amplified from only 100 pg of genomic DNA and the length of the amplicons range from 65 to 115 bp. The high sensitivity and the short amplicon sizes make the assay very suitable for typing of degraded DNA samples, and the low mutation rate of SNPs makes the assay very useful for relationship testing. Combined, these advantages make the assay well suited for disaster victim identifications, where the DNA from the victims may be highly degraded and the victims are identified via investigation of their relatives. The assay was validated according to the ISO 17025 standard and used for routine case work in our laboratory. PMID:22139655

  13. Separation of thiol and cyanide hydrolysis products of chemical warfare agents by capillary electrophoresis.

    PubMed

    Copper, Christine L; Collins, Greg E

    2004-03-01

    The fluorescence derivatizing agent, o-phthalaldehyde (OPA), has been applied to the separation and detection of cyanide and several structurally similar thiols by capillary electrophoresis (CE)-laser induced fluorescence (LIF). Of particular interest to this investigation was the separation of 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, and cyanide, each of which are hydrolysis products or hydrolysis product simulants of the chemical warfare (CW) agents O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), O-isobutyl S-2-diethylaminoethyl methylphosphonothiolate (R-VX), and tabun (GA). Other structurally similar thiols simultaneously resolved by this method include 1-pentanethiol and 2-mercaptoethanol. Instrumental parameters were probed and optimum values for capillary length (50 cm) and inner diameter (75 microm), injection time (30 s) and field strength (15 kV) were determined. Sample stacking methods enabled detection limits of 9.3 microg/L for cyanide, 1.8 microg/L for 2-diethylaminoethanethiol, 35 microg/L for 2-dimethylaminoethanethiol, 15 microg/L for 2-mercaptoethanol, and 89 microg/L for 1-pentanethiol. The linearity of the method was verified over an order of magnitude and the reproducibility was found to be 3.0%.

  14. Separation of thiol and cyanide hydrolysis products of chemical warfare agents by capillary electrophoresis.

    PubMed

    Copper, Christine L; Collins, Greg E

    2004-03-01

    The fluorescence derivatizing agent, o-phthalaldehyde (OPA), has been applied to the separation and detection of cyanide and several structurally similar thiols by capillary electrophoresis (CE)-laser induced fluorescence (LIF). Of particular interest to this investigation was the separation of 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, and cyanide, each of which are hydrolysis products or hydrolysis product simulants of the chemical warfare (CW) agents O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), O-isobutyl S-2-diethylaminoethyl methylphosphonothiolate (R-VX), and tabun (GA). Other structurally similar thiols simultaneously resolved by this method include 1-pentanethiol and 2-mercaptoethanol. Instrumental parameters were probed and optimum values for capillary length (50 cm) and inner diameter (75 microm), injection time (30 s) and field strength (15 kV) were determined. Sample stacking methods enabled detection limits of 9.3 microg/L for cyanide, 1.8 microg/L for 2-diethylaminoethanethiol, 35 microg/L for 2-dimethylaminoethanethiol, 15 microg/L for 2-mercaptoethanol, and 89 microg/L for 1-pentanethiol. The linearity of the method was verified over an order of magnitude and the reproducibility was found to be 3.0%. PMID:15004852

  15. Structural characterization of antibody drug conjugate by a combination of intact, middle-up and bottom-up techniques using sheathless capillary electrophoresis - Tandem mass spectrometry as nanoESI infusion platform and separation method.

    PubMed

    Said, Nassur; Gahoual, Rabah; Kuhn, Lauriane; Beck, Alain; François, Yannis-Nicolas; Leize-Wagner, Emmanuelle

    2016-04-28

    Antibody-drug conjugates (ADCs) represent a fast growing class of biotherapeutic products. Their production leads to a distribution of species exhibiting different number of conjugated drugs overlaying the inherent complexity resulting from the monoclonal antibody format, such as glycoforms. ADCs require an additional level of characterization compared to first generation of biotherapeutics obtained through multiple analytical techniques for complete structure assessment. We report the development of complementary approaches implementing sheathless capillary electrophoresis-mass spectrometry (sheathless CE-MS) to characterize the different aspects defining the structure of brentuximab vedotin. Native MS using sheathless CE-MS instrument as a nanoESI infusion platform enabled accurate mass measurements and estimation of the average drug to antibody ratio alongside to drug load distribution. Middle-up analysis performed after limited IdeS proteolysis allowed to study independently the light chain, Fab and F(ab')2 subunits incorporating 1, 0 to 4 and 0 to 8 payloads respectively. Finally, a CZE-ESI-MS/MS methodology was developed in order to be compatible with hydrophobic drug composing ADCs. From a single injection, complete sequence coverage could be achieved. Using the same dataset, glycosylation and drug-loaded peptides could be simultaneously identified revealing robust information regarding their respective localization and abundance. Drug-loaded peptide fragmentation mass spectra study demonstrated drug specific fragments reinforcing identification confidence, undescribed so far. Results reveal the method ability to characterize ADCs primary structure in a comprehensive manner while reducing tremendously the number of experiments required. Data generated showed that sheathless CZE-ESI-MS/MS characteristics position the methodology developed as a relevant alternative for comprehensive multilevel characterization of these complex biomolecules. PMID:27046210

  16. Capillary electrophoresis of the mycotoxin zearalenone using cyclodextrin-enhanced fluorescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain of the cyclodextrins are capable of significantly enhancing the native fluorescence of the estrogenic mycotoxin zearalenone (ZEN). Twenty-two cyclodextrins (CDs) were screened for their ability to enhance the fluorescence of ZEN in a capillary electrophoresis-laser induced fluorescence (CE-...

  17. PRECONCENTRATION OF ALIPHATIC AMINES FROM WATER DETERMINED BY CAPILLARY ELECTROPHORESIS WITH INDIRECT UV DETECTION

    EPA Science Inventory

    Preconcentration methodology based on adsorption chromatographies for enriching aliphatic amines (c1 to C4 substituted primary, secondary, and tertiary) and alkanolamines in water was studied by free zone capillary electrophoresis (CZE)with indirect UV detection. The solid-phase ...

  18. CAPILLARY ELECTROPHORESIS-ELECTROSPRAY MASS SPECTRA OF THE HERBICIDES PARAQUAT AND DIQUAT

    EPA Science Inventory

    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...

  19. Disposable pen-shaped capillary gel electrophoresis cartridge for fluorescence detection of bio-molecules

    NASA Astrophysics Data System (ADS)

    Amirkhanian, Varoujan; Tsai, Shou-Kuan

    2014-03-01

    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.

  20. DETERMINATION OF IONIZATION CONSTANTS OF HETEROCYCLIC AROMATIC AMINES USING CAPILLARY ZONE ELECTROPHORESIS. (R824100)

    EPA Science Inventory

    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...

  1. Nanometal-Oxide Sunscreen Agents by Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry

    EPA Science Inventory

    Capillary electrophoresis with detection by ICPMS is being explored to characterize nanomaterials in waste water treatment plant effluents. TiO2 and ZnO, being widely used as UV filters in personal care products, plastics, and paints, are of concern as they enter the environment...

  2. Determination of dissociation constants of aristolochic acid I and II by capillary electrophoresis with carboxymethyl chitosan-coated capillary.

    PubMed

    Fu, Xiaofang; Liu, Yi; Li, Wei; Bai, Yu; Liao, Yiping; Liu, Huwei

    2011-07-15

    Aristolochic acid-I and aristolochic acid-II have been proved to be the main bioactive and toxic component in Aristolochia plants. As a result, the determination of their dissociation constants, which are important property parameters for weak acids, is highly desired for related pharmacological and toxicological studies. In this work, the dissociation constant values of aristolochic acid-I and aristolochic acid-II were determined by capillary electrophoresis using carboxymethyl chitosan-coated capillary, based on their electrophoretic mobilities by using nonlinear regression as well as linear regression, showing that the two models give comparable results. The data were also compared with those obtained by capillary electrophoresis with polybrene-coated capillary, and no conspicuous difference was observed. The correlation coefficients were all higher than 0.998 for both linear and nonlinear regression model. The pKa values were found to be 3.3±0.1 for aristolochic acid-I and 3.2±0.1 for aristolochic acid-II.

  3. A low-makeup beveled tip capillary electrophoresis /electrospray ionization mass spectrometry interface for micellar electrokinetic chromatography and nonvolatile buffer capillary electrophoresis.

    PubMed

    Tseng, Mei-Chun; Chen, Yet-Ran; Her, Guor-Rong

    2004-11-01

    A robust interface has been developed for interfacing micellar electrokinetic chromatography (MEKC) and nonvolatile buffer capillary electrophoresis (CE) to electrospray ionization mass spectrometry (ESI-MS). The interface consists of two parallel capillaries for separation (50 microm i.d. x 155 microm o.d.) and makeup (50 microm i.d. x 155 microm o.d.) housed within a larger capillary (530 microm i.d. x 690 microm o.d.). The capillaries terminate in a single tapered tip having a beveled edge. The use of a tapered beveled edge results in a greater tip orifice diameter (75 microm) than in a previous design from our laboratory (25 microm) that used a flat tip. While maintaining a similar optimum flow rate and consequently similar sample dilution, a 75-microm beveled emitter is more rugged than a 25-microm flat tip. Furthermore, the incorporation of a sheath liquid capillary allows the compositions of the final spray solution to be controlled. The application of this novel CE/ESI-MS interface was demonstrated for MEKC using mixtures of triazines (positive ion mode) and phenols (negative ion mode). The ability to perform CE/ESI-MS using a nonvolatile buffer was demonstrated by the analysis of gangliosides with a buffer consisting of 40 mM borate and 20 mM alpha-cyclodextrin.

  4. Fingerprint analysis and synthetic adulterant search in Hedera helix formulations by capillary electrophoresis.

    PubMed

    Cianchino, V; Ortega, C; Acosta, G; Martínez, L D; Gomez, M R

    2007-04-01

    A high-performance capillary electrophoretic (CE) method has been developed for obtaining electropherograms of various extracts and the commercial formulation (fingerprints) of Hedera helix L used in Argentina as a cough's treatment. Also, a capillary zone electrophoresis (CZE) method was developed for the search, identification and determination of some possible adulterants. These likely adulterants are common synthetic drugs used in respiratory diseases (antitussive, decongestant and bronchodilator agents). Under optimum conditions, the analytes (ephedrine, codeine, diphenhydramine and constituents of H. helix formulations) were separated within less than 10 min in 20 mM sodium tetraborate buffer (pH 9.0). The present procedure was validated with respect to selectivity, linearity range, limits of detection (LOD) and quantification (LOQ), precision (repeatability and intermediate precision), solution stability and accuracy; the results obtained were satisfactory. Good linearity was obtained over two orders of magnitude and detection limits (S/N = 3) were better than 1.2 microg ml(-1) for all analytes. The CE methodology was successfully applied to the search and subsequent determination of ephedrine, codeine and diphenhydramine in H. helix extracts and its phytopharmaceutical products. PMID:17484280

  5. Direct electrokinetic injection of inorganic cations from whole fruits and vegetables for capillary electrophoresis analysis.

    PubMed

    Kalsoom, Umme; Guijt, Rosanne M; Boyce, Mary C; Townsend, Ashley T; Haselberg, Rob; Breadmore, Michael C

    2016-01-01

    A novel approach for the direct injection from plant tissues without any sample pre-treatment has been developed by simply placing a small piece of the tissue into a capillary electrophoresis vial followed by application of a voltage for electrokinetic injection. Separations of sodium, potassium, calcium and magnesium were achieved using a BGE comprising 10mM imidazole and 2.5mM 18-crown-6-ether at pH 4.5. The addition of 2% (m/v) hydroxypropylmethyl cellulose to the separation buffer allowed for precise and accurate electrokinetic injection of ions from the plant material by halting the movement of tissue fluid into the capillary. This method provides both qualitative and quantitative data of inorganic cations, with quantitation in zucchini, mushroom and apple samples in agreement with Sector Field Inductively Coupled Plasma Mass Spectrometric analysis (r(2)=0.98, n=9). This method provides a new way for rapid, quantitative analysis by eliminating sample preparation procedures, and has great potential for a range of applications in plant science and food chemistry. PMID:26422302

  6. Direct electrokinetic injection of inorganic cations from whole fruits and vegetables for capillary electrophoresis analysis.

    PubMed

    Kalsoom, Umme; Guijt, Rosanne M; Boyce, Mary C; Townsend, Ashley T; Haselberg, Rob; Breadmore, Michael C

    2016-01-01

    A novel approach for the direct injection from plant tissues without any sample pre-treatment has been developed by simply placing a small piece of the tissue into a capillary electrophoresis vial followed by application of a voltage for electrokinetic injection. Separations of sodium, potassium, calcium and magnesium were achieved using a BGE comprising 10mM imidazole and 2.5mM 18-crown-6-ether at pH 4.5. The addition of 2% (m/v) hydroxypropylmethyl cellulose to the separation buffer allowed for precise and accurate electrokinetic injection of ions from the plant material by halting the movement of tissue fluid into the capillary. This method provides both qualitative and quantitative data of inorganic cations, with quantitation in zucchini, mushroom and apple samples in agreement with Sector Field Inductively Coupled Plasma Mass Spectrometric analysis (r(2)=0.98, n=9). This method provides a new way for rapid, quantitative analysis by eliminating sample preparation procedures, and has great potential for a range of applications in plant science and food chemistry.

  7. Fingerprint analysis and synthetic adulterant search in Hedera helix formulations by capillary electrophoresis.

    PubMed

    Cianchino, V; Ortega, C; Acosta, G; Martínez, L D; Gomez, M R

    2007-04-01

    A high-performance capillary electrophoretic (CE) method has been developed for obtaining electropherograms of various extracts and the commercial formulation (fingerprints) of Hedera helix L used in Argentina as a cough's treatment. Also, a capillary zone electrophoresis (CZE) method was developed for the search, identification and determination of some possible adulterants. These likely adulterants are common synthetic drugs used in respiratory diseases (antitussive, decongestant and bronchodilator agents). Under optimum conditions, the analytes (ephedrine, codeine, diphenhydramine and constituents of H. helix formulations) were separated within less than 10 min in 20 mM sodium tetraborate buffer (pH 9.0). The present procedure was validated with respect to selectivity, linearity range, limits of detection (LOD) and quantification (LOQ), precision (repeatability and intermediate precision), solution stability and accuracy; the results obtained were satisfactory. Good linearity was obtained over two orders of magnitude and detection limits (S/N = 3) were better than 1.2 microg ml(-1) for all analytes. The CE methodology was successfully applied to the search and subsequent determination of ephedrine, codeine and diphenhydramine in H. helix extracts and its phytopharmaceutical products.

  8. [Determination of target compounds in cefoperazone sodium and tazobactam sodium for injection by capillary electrophoresis].

    PubMed

    Jiang, Ruiyuan; Sun, Guoxiang

    2012-01-01

    A capillary zone electrophoresis (CZE) method was developed for the simultaneous determination of cefoperazone sodium and tazobactam sodium in the injectable powder of cefoperazone sodium and tazobactam sodium with hydrochlorothiazide as the internal standard. The operation was carried out on a quartz capillary (75 cm x 75 microm i. d. , 63 cm effective length). The electrophoretic conditions were as follows: 40 mmol/L borax solution as the back ground electrolyte (BGE), 12. 0 kV applied voltage, 220 nm as the detection wavelength; the sample solution was injected by hydraulic pressure for 10 s at the height of 10 cm. The cefoperazone and tazobactam showed good linear relationship in the ranges of 0.25-3.96 g/L and 0.062-0.99 g/L with the correlation coefficients of 0.999 5 and 0.999 6, respectively. The relative standard deviations of relative peak areas were less than 3%. The preparation was stable in 208 min. The recovery results met the methodology requirements. The method is simple, rapid, reproducible, and suitable to control the quality of cefoperazone sodium and tazobactam sodium injectable powder. PMID:22667102

  9. Fast separation and analysis of reduced monoclonal antibodies with capillary zone electrophoresis coupled to mass spectrometry.

    PubMed

    Zhao, Yimeng; Sun, Liangliang; Knierman, Michael D; Dovichi, Norman J

    2016-02-01

    Capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) was used for analysis of reduced antibodies. We first developed a simple protocol to condition commercial linear-polyacrylamide coated capillaries for use in top-down proteomics. We then suspended reduced antibodies in a solution of 35% acetic acid, 50% acetonitrile in water. Heavy and light chains were baseline resolved within 10 min and with 3-30 µg/mL detection limits using a 0.1% aqueous formic acid background electrolyte. Quintuplicate runs of a two-antibody mixture produced relative standard deviations of ∼1% in migration time and 10% in peak amplitudes. Resolution was further improved for the two-antibody mixture by using 5% acetic acid as the background electrolyte, highlighting the potential of capillary electrophoresis-mass spectrometry for analysis of antibody mixtures. PMID:26653481

  10. Quality by design in the chiral separation strategy for the determination of enantiomeric impurities: development of a capillary electrophoresis method based on dual cyclodextrin systems for the analysis of levosulpiride.

    PubMed

    Orlandini, S; Pasquini, B; Del Bubba, M; Pinzauti, S; Furlanetto, S

    2015-02-01

    Quality by design (QbD) concepts, in accordance with International Conference on Harmonisation Pharmaceutical Development guideline Q8(R2), represent an innovative strategy for the development of analytical methods. In this paper QbD principles have been comprehensively applied in the set-up of a capillary electrophoresis method aimed to quantify enantiomeric impurities. The test compound was the chiral drug substance levosulpiride (S-SUL) and the developed method was intended to be used for routine analysis of the pharmaceutical product. The target of analytical QbD approach is to establish a design space (DS) of critical process parameters (CPPs) where the critical quality attributes (CQAs) of the method have been assured to fulfil the desired requirements with a selected probability. QbD can improve the understanding of the enantioseparation process, including both the electrophoretic behavior of enantiomers and their separation, therefore enabling its control. The CQAs were represented by enantioresolution and analysis time. The scouting phase made it possible to select a separation system made by sulfated-β-cyclodextrin and a neutral cyclodextrin, operating in reverse polarity mode. The type of neutral cyclodextrin was included among other CPPs, both instrumental and related to background electrolyte composition, which were evaluated in a screening phase by an asymmetric screening matrix. Response surface methodology was carried out by a Doehlert design and allowed the contour plots to be drawn, highlighting significant interactions between some of the CPPs. DS was defined by applying Monte-Carlo simulations, and corresponded to the following intervals: sulfated-β-cyclodextrin concentration, 9-12 mM; methyl-β-cyclodextrin concentration, 29-38 mM; Britton-Robinson buffer pH, 3.24-3.50; voltage, 12-14 kV. Robustness of the method was examined by a Plackett-Burman matrix and the obtained results, together with system repeatability data, led to define a method

  11. Laser induced fluorescence and Raman spectroscopy in capillary electrophoresis as an possible instrument for extraterrestrial life signs detection.

    NASA Astrophysics Data System (ADS)

    Mikhail, Gorlenko; Cheptcov, Vladimir; Anton, Maydykovskiy; Eugeniy, Vasilev

    The one of a significant aims in extraterrestrial exploration is a seeking for a life traces in a open space and planetary objects. Complex composition and unknown origin of suspected signs of life required у new analytical approaches and technical solutions. The promising assai here can be Laser induced fluorescence and Raman spectroscopy methods. The combined instrument developed by our team reveal the advantage of capillary electrophoresis assays in a junction with laser induced fluorescence detection technology. We optimized excitation configuration of fluorescence in capillary electrophoresis to reduce pumping laser power up to 1 mW and decrease background scattering. The improvement of the device sensitivity at poor sample concentration we achieved by incorporating fluorescence flow-through cuvette into spectrometer. That allows to simplify setup, to minimize weight and increase reproducibility of measurements. The device has been tasted in complex organic chemical mixes and microbial strains differentiation tasks. 3d multinational spectra allow us to increase the spectra information loads in comparison with ordinary capillary electrophoresis approaches. Possible updating the device with Raman approach can even furthermore multiple the differentiation power of the instrument. The analytical module developed using this approach can be potentially effectively used in extraterrestrial researches as a payload of the future spacecraft.

  12. Single molecule fluorescence burst detection of DNA fragments separated by capillary electrophoresis

    SciTech Connect

    Haab, B.B.; Mathies, R.A.

    1995-09-15

    A method has been developed for detecting DNA separated by capillary gel electrophoresis (CGE) using single molecule photon burst counting. A confocal fluorescence microscope was used to observe the fluorescence bursts from single molecules of DNA multiply labeled with the thiazole orange derivative TO6 as they passed through the nearly 2-{mu}m diameter focused laser beam. Amplified photo-electron pulses from the photomultiplier are grouped into bins of 360-450 {mu}s in duration, and the resulting histogram is stored in a computer for analysis. Solutions of M13 DNA were first flowed through the capillary at various concentrations, and the resulting data were used to optimize the parameters for digital filtering using a low-pass Fourier filter, selecting a discriminator level for peak detection, and applying a peak-calling algorithm. The optimized single molecule counting method was then applied to an electrophoretic separation of M13 DNA and to a separation of pBR 322 DNA from pRL 277 DNA. Clusters of discreet fluorescence bursts were observed at the expected appearance time of each DNA band. The auto-correlation function of these data indicated transit times that were consistent with the observed electrophoretic velocity. These separations were easily detected when only 50-100 molecules of DNA per band traveled through the detection region. This new detection technology should lead to the routine analysis of DNA in capillary columns with an on-column sensitivity of nearly 100 DNA molecules/band or better. 45 refs., 10 figs.

  13. An improvement of restriction analysis of bacteriophage DNA using capillary electrophoresis in agarose solution.

    PubMed

    Klepárník, K; Malá, Z; Doskar, J; Rosypal, S; Bocek, P

    1995-03-01

    Seven representatives of the serogroup B Staphylococcus aureus bacteriophages, 29, 53, 55, 83A, 85, phi 11 and 80 alpha, were examined by capillary electrophoresis (CE) for genomic homology using DNA restriction analysis. Genomic DNA of individual bacteriophages was cleaved by HindIII restriction endonuclease, and the resulting restriction fragments were separated by standard horizontal agarose slab gel electrophoresis (SGE) as well as by CE in low-melting-point agarose solutions. The number and size of restriction fragments identified by both methods were compared. The high separation power of CE makes it possible to extend the restriction fragment patterns. In most of the restriction patterns, some additional restriction fragments as small as 150 bp, not identified by SGE, were detected. With respect to speed, high separation efficiency, low sample consumption and automation, CE offers a simple procedure for processing of multiple samples cost-effectively in a reasonable time. The comparison of the complemented restriction patterns of the different phage strains and the subsequent identification of their common fragments leads to a deeper understanding of their phylogenetic relationships. The genome homologies expressed for individual phage pairs in terms of coefficient F values ranged from 15 to 69%. These values are in good accordance with the degree of DNA homology of these phages as determined by DNA hybridization studies and thermal denaturation analysis of DNA by other authors. The total size of each phage genome was estimated by adding the sizes of individual restriction fragments.

  14. Electromagnetic induction detector for capillary electrophoresis and its application in pharmaceutical analysis.

    PubMed

    Yang, Xiu-Juan; Chen, Zuan-Guang; Liu, Cui; Li, Ou-Lian

    2010-10-15

    A new electromagnetic induction detector for capillary electrophoresis and its application are described. The detector is consisted of an inductor, a resistor, a high-frequency signal generator and a high-frequency millivoltmeter. The conditions affecting the response of the detector, including dimension of the magnetic ring, position of the capillary, number of coil turns, frequency, excitation voltage and value of the resistor were examined and optimized. The feasibility of the proposed detector was evaluated by detection of inorganic ions and separation of amino aids. Its quantification applicability was investigated by determination of aspirin and paracetamol in pharmaceutical preparation (Akafen powder). The primary factors affecting separation efficiency, which include variety of buffer, buffer concentration, injection time and injection height and separation voltage, were researched. Experimental results demonstrated that this new detector showed a well-defined correlation between sample concentrations and responses (r=0.997-0.999), with detection limits of 30 μmol L(-1) for aspirin and 10 μmol L(-1) for paracetamol, as well as good reproducibility and stability. Compared with currently available detection techniques, this new detector has several advantages, such as simple construction, no complicated elements, ease of assembly and operation, and potential for universal applications. It can be an alternative to the traditional methods in the quality control of the pharmaceutical preparations.

  15. Determination of ibuprofen and flurbiprofen in pharmaceuticals by capillary zone electrophoresis.

    PubMed

    Hamoudová, Rafifa; Pospísilová, Marie

    2006-06-16

    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).

  16. Layer-by-layer assembly of polyelectrolyte and nanoparticles, monitored by capillary electrophoresis.

    PubMed

    Liu, Qian; Yao, Lihua; Shen, Qinpeng; Nie, Zhou; Guo, Manli; Yao, Shouzhuo

    2009-11-23

    Layer-by-layer (LBL) assembly is a versatile nanofabrication technique, and investigation of its kinetics is essential for understanding the assembly mechanism and optimizing the assembly procedure. In this work, the LBL assembly of polyelectrolyte and nanoparticles were monitored in situ by capillary electrophoresis (CE) for the first time. The assembly of poly(diallyldimethylammonium chloride) (PDDA), and gold nanoparticles (AuNPs) on capillary walls causes surface-charge neutralization and resaturation, and thus yields synchronous changes in the electroosmotic flow (EOF). The EOF data show that formation of multilayers follows first-order adsorption kinetics. On the basis of the fit results, influencing factors, including number of layers, concentration of materials, flow rate, and size of AuNPs, were investigated. The stability and robustness of the assembled coatings were also characterized by CE. It was found that degradation of PDDA layers follows first-order chemical kinetics, while desorption of AuNPs takes place in a disorderly manner. The substrate strongly affects assembly of the underlying layer, while this effect is rapidly screened with increasing number of layers. Furthermore, we demonstrate that the EOF measuring step does not disturb LBL assembly, and the proposed method is reliable and rugged. This work not only studies in detail the LBL adsorption/desorption process of polyelectrolyte and nanoparticles, but also offers an alternative tool for monitoring multilayer buildup. It may also reveal the potential of CE in fields other than analytical separation. PMID:19834943

  17. Simultaneous determination of S-adenosylmethionine and S-adenosylhomocysteine by capillary zone electrophoresis.

    PubMed

    Pañak, K C; Giorgieri, S A; Díaz, L E; Ruiz, O A

    1997-10-01

    A reproducible, rapid procedure for the simultaneous quantitative separation of S-adenosylmethionine and S-adenosylhomocysteine by capillary zone electrophoresis has been developed. Separations were performed by using an uncoated capillary of 60 cm effective length and 50 microm ID, 40 mM sodium phosphate buffer, pH 2.50, as background electrolyte solution, and 30 kV. On-line detection was carried out at 254 nm. Under the conditions selected we resolved a standard solution containing S-adenosylmethionine and S-adenosylhomocysteine in a run time shorter than 8 min. A mass detection limit in the range of 10 fmol was achieved. Adenosyl-L-methionine, S[methyl-3H] has also been assayed under the same experimental conditions. Other related compounds did not show interference, including those derived from the hydrolysis of S-adenosylmethionine. The present method allows simultaneous determination of these compounds, which play an important role in many microbiological and enzymatic research studies.

  18. Pharmacokinetic study of trimebutine maleate in rabbit blood using in vivo microdialysis coupled to capillary electrophoresis.

    PubMed

    Wang, Li; Zhang, Zhujun; Yang, Weiping

    2005-09-15

    In vivo microdialysis was used together with capillary electrophoresis (CE) to monitor the concentration of trimebutine maleate (TM) in rabbit blood. Dialysis probe was perfused at 3 microl/min resulting in relative recovery of 26.6+/-3.1% (n=3). After a one step sample preparation the samples were injected directly into the capillary. TM was detected on-column using UV detector at 214 nm. Separation of TM from other components in the dialysate was achieved within 15 min. Evaluation was based on the relative collected peak height (TM/IS). The response for TM in the blood dialysate was linear over the range of 0.5-100 microg/ml. The detection limit of TM in the blood dialysate was 0.1 microg/ml (S/N=3). This method has been successfully applied to the pharmacokinetic study of trimebutine maleate in rabbit blood following oral administration of 200 mg/kg. It provides a fast and simple technique for the pharmacokinetic study of TM in vivo. PMID:15939564

  19. Determination of bromate ion in drinking water by capillary zone electrophoresis with direct photometric detection.

    PubMed

    Takayanagi, Toshio; Ishida, Makoto; Mbuna, Julius; Driouich, Rim; Motomizu, Shoji

    2006-09-22

    Bromate ion in drinking water was determined by capillary zone electrophoresis (CZE) with direct photometric detection. Bromate ion in the sample solution was introduced and concentrated into the capillary by electrokinetic injection for 50s at -10 kV. Electrophoretic separation was made at an applied voltage of -25 kV and bromate ion was detected at wavelength 193 nm, at which the baseline was stabilized with less UV-absorbing acidic phosphate buffer. Bromate ion was detected within 5 min in the electropherogram. By increasing the electric conductivity in the migrating solution with 10 mM Na2SO4, a limit of detection (LOD) of 9 x 10(-10)M (0.1 microg/L BrO3-) was achieved. The proposed method was applied to the analysis of tap water and river water samples, but bromate ion was not detected. Because the practical samples contain relatively large amount of foreign ionic substances, the tap water sample was diluted to avoid the matrix ions. Bromate ion added in a tap water at the concentration of 8 x 10(-8)M was quantitatively recovered by diluting it 1/10.

  20. Determination of free L- and D-alanine in hydrolysed protein fertilisers by capillary electrophoresis.

    PubMed

    Cavani, Luciano; Ciavatta, Claudio; Gessa, Carlo

    2003-01-24

    of racemisation of hydrolysed protein fertilisers (HPFs) using an The objective of this study was to determine the degree inexpensive and easy to handle analytical method for qualitative control of the products. Using a polyacrylamide coated capillary and a run buffer containing 0.1 M Tris-borate+2.5 mM EDTA-Na2+0.1% sodium dodecylsulfate+10 mM beta-cyclodextrin a quantitative separation of D- and L-alanine (Ala) was made from an not treated HPF sample derivatised with dansyl chlorine by capillary electrophoresis. The D-Ala:[D-Ala+L-Ala] ratio, called degree of racemisation (RD), was calculated. The analysis of ten commercial HPFs has shown that more than 60% of HPFs have an RD > or = 40%. while only one product has shown an RD <5%. These results showed that most of the HPFs on the market are obtained with strong hydrolytic processes and high contents of D-amino acids are probably less effective as plant nutrients or even potentially dangerous to plants.

  1. Determination of cellular carbohydrates in peanut fungal pathogens and baker's yeast by capillary electrophoresis and electrochromatography.

    PubMed

    Zhang, M; Melouk, H A; Chenault, K; El Rassi, Z

    2001-11-01

    In this work, the quantitation of cellular carbohydrates, namely chitin and glucan, in peanut fungal pathogens and baker's yeast was carried out by capillary electrophoresis (CE) and capillary electrochromatography (CEC). The chitin and glucan of the fungi were hydrolyzed by the enzymes chitinase and glucanase, respectively, to their corresponding sugar monomers N-acetylglucosamine (GlcNAc) and glucose (Glc). These two monosaccharides were then tagged with 6-aminoquinoline (6-AQ) to allow their separation and detection in CE and CEC. The 6-AQ derivatives of GlcNAc and Glc formed the basis for the determination by CE and CEC of chitin and glucan in peanut fungi and baker's yeast. Several parameters affecting the separation of the 6-AQ derivatives of GlcNAc and Glc, including the separation voltage and the composition of the running electrolyte, were investigated. Under the optimized separation conditions, the contents of cellular carbohydrates including N-acetylglucosamine, chitin, glucose, and glucan in some fungi, such as Sclerotinia minor, Sclerotium rolfsii, and baker's yeast, were successfully determined. The method described here allowed the assessment of genetic differences in Sclerotium rolfsii isolates from various locations. PMID:11714314

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

    SciTech Connect

    Tan, H.

    1999-03-31

    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. Revised Capillary Breakup Rheometer Method

    NASA Astrophysics Data System (ADS)

    Lu, Louise; Schultz, William; Solomon, Michael

    2014-11-01

    Rather than integrate the one-dimensional equation of motion for a capillary breakup rheometer, we take the axial derivative of that equation. This avoids the determination of the axial force with all of its complications and correction factors. The resulting evolutionary equation that involves either two or four derivatives of the capillary radius as a function of the axial coordinate determines the ratio of elongational viscosity to surface tension coefficient. We examine several silicone and olive oils to show the accuracy of the method for Newtonian fluids. We will discuss our surface tension measurement techniques and briefly describe measurements of viscoelastic materials, including saliva.

  4. On the use of capillary electrophoresis for the determination of inorganic anions and cations, and carbohydrates in residues collected after a simulated suicide bombing attack.

    PubMed

    Sarazin, Cédric; Delaunay, Nathalie; Costanza, Christine; Eudes, Véronique; Gareil, Pierre

    2013-01-15

    In order to train scientist field investigators after terrorist attacks, the laboratory of the Prefecture de Police of Paris simulated a suicide bombing attack in a bus. After collection of the residues, analyses were carried out to determine the composition of the original explosive charge. This article focuses on the combined use, for the first time, of three new capillary electrophoresis methods for the determination of inorganic anions and cations, and carbohydrates in two representative extracts. Capillary electrophoresis appears as an effective tool to identify and quantify the compounds in real extracts and is fully complementary to chromatographic methods. PMID:23200391

  5. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis.

    PubMed

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

    2014-07-01

    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.

  6. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis

    PubMed Central

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

    2014-01-01

    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. PMID:25126117

  7. Elimination of the artefact peaks in capillary electrophoresis determination of glutamate by using organic solvents in sample preparation.

    PubMed

    Campos, Camila Dalben Madeira; de Campos Braga, Patricia Aparecida; Reyes, Felix Guillermo Reyes; da Silva, José Alberto Fracassi

    2015-11-01

    Focusing on the demand from the food industry for fast and reliable alternative methods to control the quality of food products, we present in this paper a method for amino acid separation and glutamic acid quantification in complex matrices employing capillary electrophoresis with capacitively coupled contactless conductivity detection. We demonstrate by simulation and experimentally the use of organic solvents in sample preparation to prevent peak splitting and increase stacking in capillary electrophoretic separations of amino acids. Additionally, we obtained results for glutamic acid quantification comparable to those obtained via traditional methods used at industrial sites. We tested premium and low-cost samples with large variations in their glutamic acid content, which demonstrated the wide range of applicability of the method presented herein. The results of the proposed capacitively coupled contactless conductivity detection based capillary electrophoresis method agreed with those obtained by an enzymatic detector and ultra high performance liquid chromatography coupled to tandem mass spectrometry, considering a confidence level of 95%. PMID:26332708

  8. Evaluation of capillary electrophoresis for determining the concentration of dissolved silica in geothermal brines.

    PubMed

    Santoyo, E; García, R; Aparicio, A; Verma, Surendra P; Verma, M P

    2005-04-15

    The determination of silica concentrations in geothermal brines is widely recognized as a difficult analytical task due to its complex chemical polymerization kinetics that occurs during sample collection and chemical analysis. Capillary electrophoresis (CE) has been evaluated as a new reliable analytical method to measure silica (as silicates) in geothermal brines. Synthetic and geothermal brine samples were used to evaluate CE methodology. A capillary electrophoresis instrument, Quanta 4000 (Waters-Millipore) coupled with a Waters 820 workstation was used to carry out the experimental work. The separation of silicates was completed in approximately 5.5 min using a conventional fused-silica capillary (75 microm i.d. x 375 microm o.d. x 60 cm total length). A hydrostatic injection (10 cm for 20 s at 25 degrees C) was employed for introducing the samples. The carrier electrolyte consisted of 10 mM sodium chromate, 3 mM tetradecyltrimethyl-ammonium hydroxide (TTAOH), 2 mM sodium carbonate, and 1 mM sodium hydroxide, adjusted to a pH 11.0 +/- 0.1. Silicates were determined using an indirect UV detection at a wavelength of 254 nm with a mercury lamp and with a negative power supply (-15 kV). A good reproducibility in the migration times (%R.S.D. approximately 1.6%) based on six non-consecutive injections of synthetic brine solutions was obtained. A linear response between silica concentration and corrected peak area was observed. Ordinary (OLR) and weighted (WLR) linear regression models were used for calculating silica concentrations in all samples using the corresponding fitted calibration curves. The analytical results of CE were finally compared with the most probable values of synthetic reference standards of silica using the Student's t-test. No significant differences were found between them at P = 0.01. Similarly, the atomic absorption spectrometry (AAS) results were also compared with the most probable concentrations of the same reference standards, finding

  9. One step physically adsorbed coating of silica capillary with excellent stability for the separation of basic proteins by capillary zone electrophoresis.

    PubMed

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

    2015-11-01

    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.

  10. One step physically adsorbed coating of silica capillary with excellent stability for the separation of basic proteins by capillary zone electrophoresis.

    PubMed

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

    2015-11-01

    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. PMID:26452799

  11. Capillary electrophoresis of viruses, subviral particles and virus complexes.

    PubMed

    Kremser, Leopold; Bilek, Gerhard; Blaas, Dieter; Kenndler, Ernst

    2007-07-01

    CZE and CIEF were so far applied to the analysis of tobacco mosaic virus, Semliki forest virus, human rhinovirus, adenovirus, norovirus and the bacteriophages T5 and MS2. The concentration of viral or subviral particles, of capsid proteins and viral genomes were determined, their electrophoretic mobilities and pI values were measured and bioaffinity reactions between viruses and antibodies, antibody fragments and receptor fragments were assessed. The role of detergents added to the BGE to obtain reproducible electrophoretic conditions was elucidated. The analytes were detected via their UV-absorbance or via fluorescence after derivatization of the viral capsid, the nucleic acid, or both. A new dimension to the detection is added by the possibility of making use of the viral infectivity. At least in theory, this allows for the unequivocal identification of a single infectious virus particle after collection at the capillary outlet. This review summarizes the 25 papers so far published on this topic.

  12. Simultaneous determination of caffeine, paracetamol, and ibuprofen in pharmaceutical formulations by high-performance liquid chromatography with UV detection and by capillary electrophoresis with conductivity detection.

    PubMed

    Cunha, Rafael R; Chaves, Sandro C; Ribeiro, Michelle M A C; Torres, Lívia M F C; Muñoz, Rodrigo A A; Dos Santos, Wallans T P; Richter, Eduardo M

    2015-05-01

    Paracetamol, caffeine and ibuprofen are found in over-the-counter pharmaceutical formulations. In this work, we propose two new methods for simultaneous determination of paracetamol, caffeine and ibuprofen in pharmaceutical formulations. One method is based on high-performance liquid chromatography with diode-array detection and the other on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation by high-performance liquid chromatography with diode-array detection was achieved on a C18 column (250×4.6 mm(2), 5 μm) with a gradient mobile phase comprising 20-100% acetonitrile in 40 mmol L(-1) phosphate buffer pH 7.0. The separation by capillary electrophoresis with capacitively coupled contactless conductivity detection was achieved on a fused-silica capillary (40 cm length, 50 μm i.d.) using 10 mmol L(-1) 3,4-dimethoxycinnamate and 10 mmol L(-1) β-alanine with pH adjustment to 10.4 with lithium hydroxide as background electrolyte. The determination of all three pharmaceuticals was carried out in 9.6 min by liquid chromatography and in 2.2 min by capillary electrophoresis. Detection limits for caffeine, paracetamol and ibuprofen were 4.4, 0.7, and 3.4 μmol L(-1) by liquid chromatography and 39, 32, and 49 μmol L(-1) by capillary electrophoresis, respectively. Recovery values for spiked samples were between 92-107% for both proposed methods.

  13. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, Richard D.; Udseth, Harold R.; Barinaga, Charles J.

    1995-01-01

    An improvement to the system and method for analyzing molecular constituents of a composition sample that comprises improvements to an electrospray ionization source for interfacing to mass spectrometers and other detection devices. The improvement consists of establishing a unique electrical circuit pattern and nozzle configuration, a metallic coated and conical shaped capillary outlet, coupled with sizing of the capillary to obtain maximum sensitivity.

  14. Simultaneous Detection of Genetically Modified Organisms in a Mixture by Multiplex PCR-Chip Capillary Electrophoresis.

    PubMed

    Patwardhan, Supriya; Dasari, Srikanth; Bhagavatula, Krishna; Mueller, Steffen; Deepak, Saligrama Adavigowda; Ghosh, Sudip; Basak, Sanjay

    2015-01-01

    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. PMID:26525256

  15. Simultaneous Detection of Genetically Modified Organisms in a Mixture by Multiplex PCR-Chip Capillary Electrophoresis.

    PubMed

    Patwardhan, Supriya; Dasari, Srikanth; Bhagavatula, Krishna; Mueller, Steffen; Deepak, Saligrama Adavigowda; Ghosh, Sudip; Basak, Sanjay

    2015-01-01

    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.

  16. Control of the cultivation process of antithrombin III and its characterization by capillary electrophoresis.

    PubMed

    Reif, O W; Freitag, R

    1994-10-01

    The production by baby hamster kidney cells of recombinant antithrombin III (r-AT III), the main inhibitor of thrombin, factor Xa and other proteases of the clotting cascade, was monitored by capillary isotachophoresis using mixtures of continuous spacers. The results were compared with those obtained by capillary zone electrophoresis (CZE). The downstream process, which incorporated anion-exchange and heparin affinity chromatography, was monitored by CZE under acidic conditions and voltage ramping. The purified product was characterized by its isoelectric point and molecular mass. Isoelectric points of the three major and three minor isoforms of AT III were evaluated by capillary isoelectric focusing using a pH range of 4-6 and various mobilization procedures. The molecular mass of AT III was investigated by capillary gel electrophoresis (CGE), applying removable dextran gels. Both parameters could be determined within 30 min using only one coated capillary. The results showed an excellent correspondence with those achieved with conventional slab gels. The affinity complex between AT III and thrombin could also be detected by CGE and the heparin dependence of the affinity reaction could be investigated.

  17. Use of capillary electrophoresis with laser-induced fluorescence detection to screen and liquid chromatography-tandem mass spectrometry to confirm sulfonamide residues: validation according to European Union 2002/657/EC.

    PubMed

    Hoff, Rodrigo Barcellos; Barreto, Fabiano; Kist, Tarso B Ledur

    2009-11-13

    A multiresidue method is described for determining six sulfonamides (SAs) (sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxazole, sulfaquinoxaline and sulfadimethoxine) in liver by a capillary electrophoresis screening method and a liquid chromatography coupled to tandem mass spectrometry confirmatory assay. Samples were prepared by homogenizing the tissue, with sodium hydroxide and acetonitrile. After evaporation, extracts were injected in the capillary electrophoresis system or mass spectrometry system for confirmatory analysis. The detection of analytes was achieved by laser-induced fluorescence in capillary electrophoresis. Procedures were validated according to the European Union regulation 2002/657/EC determining specificity, selectivity and detection capability for screening method and decision limit, detection capability, specificity, selectivity, trueness and precision for confirmation method. The results of validation process demonstrate that the method is suitable for application in Brazilian statutory veterinary drug residue surveillance programs. Capillary electrophoresis was proved to be a fast, robust method with low time and reagents consumption. PMID:19765714

  18. Capillary zone electrophoresis for enumeration of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in yogurt.

    PubMed

    Lim, Orathai; Suntornsuk, Worapot; Suntornsuk, Leena

    2009-03-15

    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 (%RSDs<9.3%), recovery (%R=91.7-106.7%) and limit of quantitation (1.0 x 10(6) colony forming unit per mL (CFU/mL)) were satisfactory. Results from the CE analysis of both bacteria in yogurt 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).

  19. A parallel dual-electrode detector for capillary electrophoresis.

    PubMed

    Dorris, Megan K; Crick, Eric W; Lunte, Craig E

    2012-09-01

    An approach to on-capillary dual-electrode detection for CE using a parallel electrode configuration has been developed. The parallel configuration provides two operating modes. In the first mode, one working electrode is held at an oxidizing potential and the second working electrode is held at a reducing potential. This results in redox cycling of analytes between the oxidized and reduced forms, enhancing sensitivity compared to single-electrode detection. In the second mode, both working electrodes are held at different oxidizing potentials. This mode provides electrochemical characterization of electrophoretic peaks. In the redox cyclying mode, signal enhancement of up to twofold was observed for the dual-electrode detection of phenolic acid standards compared to single-electrode detection. Variation in response of less than 10% from electrode to electrode was determined (at a concentration of 60 nM) indicating reproducible fabrication. LODs were determined to be as low as 5.0 nM for dual-electrode configuration. Using the dual-potential mode peak identification of targeted phenolic acids in whiskey samples were confirmed based on both migration time and current ratios.

  20. A parallel dual-electrode detector for capillary electrophoresis.

    PubMed

    Dorris, Megan K; Crick, Eric W; Lunte, Craig E

    2012-09-01

    An approach to on-capillary dual-electrode detection for CE using a parallel electrode configuration has been developed. The parallel configuration provides two operating modes. In the first mode, one working electrode is held at an oxidizing potential and the second working electrode is held at a reducing potential. This results in redox cycling of analytes between the oxidized and reduced forms, enhancing sensitivity compared to single-electrode detection. In the second mode, both working electrodes are held at different oxidizing potentials. This mode provides electrochemical characterization of electrophoretic peaks. In the redox cyclying mode, signal enhancement of up to twofold was observed for the dual-electrode detection of phenolic acid standards compared to single-electrode detection. Variation in response of less than 10% from electrode to electrode was determined (at a concentration of 60 nM) indicating reproducible fabrication. LODs were determined to be as low as 5.0 nM for dual-electrode configuration. Using the dual-potential mode peak identification of targeted phenolic acids in whiskey samples were confirmed based on both migration time and current ratios. PMID:22965718

  1. Characterization and quantification in capillary zone electrophoresis using direct and indirect detection

    SciTech Connect

    Chiang, Hui-Ti; Church, W.H.

    1995-12-01

    Capillary zone electrophoresis has become a major separation technique for the analysis of small volumes of materials and it is featured with the advantages of high efficiency, simplicity and rapidity. The purpose of this study was to characterize the performance of a capillary electrophoresis system in regards to the separation efficiency and quantitative capacity. Three sample introduction techniques--electromigration, gravity and pressure injection modes--were evaluated utilizing two different sample-buffer systems. Analytes phenol, benzoic acid and 2,4-dihydroxybenzoic acid were separated underpositive polarity voltage using a borate buffet and monitored with direct UV absorption detection. Mixtures of myo-inositol 2-monophosphate, myo-inositol 1,4,5-trisphosphate, and myo-inositol hexakisphosphate were separated under negative polarity voltage using a lon Phor Anionic Electrolyte Buffer containing an electroosmotic flow modifier and a background chromophore for indirect detection.

  2. Separation of cis/trans isomers of a prolyl peptide bond by capillary zone electrophoresis.

    PubMed

    Meyer, S; Jabs, A; Schutkowski, M; Fischer, G

    1994-01-01

    On capillary electrophoresis of the chemically pure thioxo peptide Ala-Phe-psi[CS-N]-Pro-Phe-4-nitroanilide a peak splitting was observed at a capillary temperature of 25 degrees C. By contrast, the oxo peptide analogue exhibits a single, sharp peak under these conditions. Both peaks of the thioxo compound coincided gradually when the temperature was increased to 60 degrees C. Peak fusion was reverted by cooling down the heated sample. This behavior could be attributed to the electrophoresis-mediated separation of the cis/trans prolyl bond isomers of the thioxo peptide, allowing data of this conformational equilibrium to be determined. Derived from computational data about molecular volume and the hydration energy of low-energy cis and trans isomeric structures, the more rapid migration of the cis form in comparison to trans may be explained by structural parameters.

  3. Capillary electrophoresis determination of non-protein amino acids as quality markers in foods.

    PubMed

    Pérez-Míguez, Raquel; Marina, María Luisa; Castro-Puyana, María

    2016-01-01

    Non-protein amino acids mainly exist in food as products formed during food processing, as metabolic intermediates or as additives to increase nutritional and functional properties of food. This fact makes their analysis and determination an attractive field in food science since they can give interesting information on the quality and safety of foods. This article presents a comprehensive review devoted to describe the latest advances in the development of (achiral and chiral) analytical methodologies by capillary electrophoresis and microchip capillary electrophoresis for the analysis of non-protein amino acids in a variety of food samples. Most relevant information related to sample treatment, experimental separation and detection conditions, preconcentration strategies and limits of detection will be provided.

  4. Development of fully automated quantitative capillary electrophoresis with high accuracy and repeatability.

    PubMed

    Xu, Yuan; Ling, Bang-Zan; Zhu, Wen-Jun; Yao, Dong; Zhang, Lin; Wang, Yan; Yan, Chao

    2016-03-01

    A quantitative capillary electrophoresis (qCE) was developed by utilizing a rotary type of nano-volume injector, an autosampler, and a thermostat with cooling capacity. The accuracy and precision were greatly improved compared with conventional capillary electrophoresis. The 10 nL volume accuracy was guaranteed by the carefully designed nano-injector with an accurate internal loop. The system repeatability (precision) in terms of RSD <0.5% for migration time and 1% for peak area were achieved by using DMSO as a test sample. We believe that this fully automated qCE system has the potential to be employed broadly in quality control and quality assurance in the pharmaceutical industry.

  5. Minimizing adsorption of histidine-tagged proteins for the study of protein-deoxyribonucleic acid interactions by kinetic capillary electrophoresis.

    PubMed

    Liyanage, Ruchi; Krylova, Svetlana M; Krylov, Sergey N

    2013-12-27

    Affinity interactions between DNA and proteins play a crucial role in many cellular processes. Kinetic Capillary Electrophoresis is a highly efficient tool for kinetic and equilibrium studies of protein-DNA interactions. Recombinant proteins, which are typically used for in vitro studies of protein-DNA interactions, are often expressed with a His tag to aid in their purification. In this work, we study how His tags affect Kinetic Capillary Electrophoresis analysis of protein-DNA interactions. We found that the addition of a His tag can increase or decrease protein adsorption to a bare-silica capillary wall, dependent on the protein. For Kinetic Capillary Electrophoresis measurements, it is essential to have as little protein adsorption as possible. We screened a number of capillary coatings to reduce adsorption of the His-tagged DNA mismatch repair protein MutS to the capillary wall and found that UltraTrol LN was the most effective coating. The effectiveness of the coating was confirmed with the prevention of adsorption of His-tagged fat mass and obesity-associated protein. Under typical conditions, the coating reduced protein adsorption to a level at which accurate Kinetic Capillary Electrophoresis analysis of protein-DNA interactions was possible. We further used Kinetic Capillary Electrophoresis to study how the His tag affected Kd of protein-DNA interactions for the MutS protein. Using UltraTrol LN, we found that the effect of the His tag was insignificant.

  6. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  7. Determination of Caffeine in Beverages by Capillary Zone Electrophoresis: An Experiment for the Undergraduate Analytical Laboratory

    NASA Astrophysics Data System (ADS)

    Conte, Eric D.; Barry, Eugene F.; Rubinstein, Harry

    1996-12-01

    Certain individuals may be sensitive to specific compounds in comsumer products. It is important to quantify these analytes in food products in order to monitor their intake. Caffeine is one such compound. Determination of caffeine in beverages by spectrophotometric procedures requires an extraction procedure, which can prove time-consuming. Although the corresponding determination by HPLC allows for a direct injection, capillary zone electrophoresis provides several advantages such as extremely low solvent consumption, smaller sample volume requirements, and improved sensitivity.

  8. Analysis of Diet Tonic Water Using Capillary Electrophoresis. An Undergraduate Instrumental Analysis Experiment

    NASA Astrophysics Data System (ADS)

    Herman, Harvey B.; Jezorek, John R.; Tang, Zhe

    2000-06-01

    An experiment for instrumental analysis is described in which components of diet tonic water are determined using capillary electrophoresis. Separation of quinine, saccharin, and benzoate in pH 7 phosphate buffer, with phenol as internal standard, is accomplished in about 12 minutes. The equipment requirements are modest: UV detection on an unmodified column. One of the components, quinine, is quantitated using a four-point standard addition calibration curve.

  9. Dynamic modification of microorganisms by pyrenebutanoate for fluorometric detection in capillary zone electrophoresis.

    PubMed

    Horká, Marie; Růzicka, Filip; Holá, Veronika; Slais, Karel

    2005-02-01

    Pyrenebutanoate, a fluorescent amphiphilic probe, is suggested here as a capillary zone electrophoresis (CZE) buffer additive for dynamic modification and analysis of microbial cells. Mixed cultures of microorganisms Escherichia coli, Candida albicans, Enterococcus faecalis and Staphylococcus epidermidis were concentrated, resolved by CZE and detected. Using UV excitation for on-column fluorometric detection, a detection sensitivity for the microorganisms on the order of from one to tens of injected cells was achieved.

  10. A comprehensive platform to investigate protein-metal ion interactions by affinity capillary electrophoresis.

    PubMed

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

    2015-03-25

    In this work, the behavior of several metal ions with different globular proteins was investigated by affinity capillary electrophoresis. Screening was conducted by applying a proper rinsing protocol developed by our group. The use of 0.1M EDTA in the rinsing solution successfully desorbs metal ions from the capillary wall. The mobility ratio was used to evaluate the precision of the method. Excellent precision for repeated runs was achieved for different protein metal ion interactions (RSD% of 0.05-1.0%). Run times were less than 6 min for all of the investigated interactions. The method has been successfully applied for the interaction study of Li(+), Na(+), Mg(2+), Ca(2+), Ba(2+), Al(3+), Ga(3+), La(3+), Pd(2+), Ir(3+), Ru(3+), Rh(3+), Pt(2+), Pt(4+), Os(3+), Au(3+), Au(+), Ag(+), Cu(1+), Cu(2+), Fe(2+), Fe(3+), Co(2+), Ni(2+), Cr(3+), V(3+), MoO4(2-) and SeO3(2-) with bovine serum albumin, ovalbumin, β-lactoglobulin and myoglobin. Different interaction values were obtained for most of the tested metal ions even for that in the same metal group. Results were discussed and compared in view of metal and semimetal group's interaction behavior with the tested proteins. The calculated normalized difference of mobility ratios for each protein-metal ion interaction and its sign (positive and negative) has been successfully used to detect the interaction and estimate further coordination of the bound metal ion, respectively. The comprehensive platform summarizes all the obtained interaction results, and is valuable for any future protein-metal ion investigation.

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

    PubMed Central

    Domínguez Vega, Elena; Marina, Maria Luisa

    2014-01-01

    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. PMID:25535077

  12. Identification of bioactive peptides in hypoallergenic infant milk formulas by capillary electrophoresis-mass spectrometry.

    PubMed

    Català-Clariana, Sergio; Benavente, Fernando; Giménez, Estela; Barbosa, José; Sanz-Nebot, Víctoria

    2010-12-17

    In this study, we use capillary electrophoresis-mass spectrometry (CE-MS) for the identification of bioactive peptides in hypoallergenic infant milk formulas (IF), which are complex bovine milk protein hydrolysates. A sample clean-up pretreatment with a citrate buffer containing dithiothreitol and urea followed by solid-phase extraction (SPE) with different reversed-phase commercial cartridges was investigated to achieve optimum detection sensitivity in CE-MS. SPE with C18, StrataX and Oasis HLB cartridges allowed detection of the largest number of low molecular mass components, but combination of C18 and StrataX results was enough to achieve an excellent coverage of the studied IF. The monoisotopic molecular mass values of the low molecular mass components obtained by capillary electrophoresis ion-trap mass spectrometry (CE-IT-MS) allowed the tentative identification of nine bioactive sequences. Only the identification of five of them could be confirmed when accurate mass measurements were performed by capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS), namely LKP, IPY, ALPM, PGPIHN and VAGTWY, which were reported to present angiotensin-converting enzyme (ACE) inhibitory and antimicrobial activity (only VAGTWY).

  13. Charge Effect on the Quantum Dots-Peptide Self-Assembly Using Fluorescence Coupled Capillary Electrophoresis.

    PubMed

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

    2016-04-01

    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.

  14. Characterization and study of transgenic cultivars by capillary and microchip electrophoresis.

    PubMed

    Domínguez Vega, Elena; Marina, Maria Luisa

    2014-01-01

    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. PMID:25535077

  15. A KINETIC STUDY OF THE METHANOLYSIS OF THE SULFONYLUREAS BENSULFURON METHYL AND SULFOMETURON METHYL USING CAPILLARY ELECTROPHORESIS

    EPA Science Inventory

    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...

  16. A Novel Protocol to Analyze Short- and Long-Chain Fatty Acids Using Nonaqueous Microchip Capillary Electrophoresis

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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).

  17. DETERMINATION OF ALIPHATIC AMINES IN WATER USING DERIVATIZATION WITH FLUORESCEIN ISOTHIOCYANATE AND CAPILLARY ELECTROPHORESIS/LASER-INDUCED FLUORESCENCE DETECTION.

    EPA Science Inventory

    Detection-oriented derivatization of aliphatic amines and amine functional groups in coumpounds of environmental interest was studied using fluorescein isothiocyanate (FITC) with separation/determination by capillary electrophoresis/laser-induced fluorescence. Determinative level...

  18. Analysis of degradation products of chemical warfare agents using capillary electrophoresis.

    PubMed

    Aleksenko, Svetlana S; Gareil, Pierre; Timerbaev, Andrei R

    2011-10-21

    Analysis of chemical warfare agents (CWAs), their precursors and degradation products (DPs) is an important verification component in support of the Chemical Weapons Convention and urgently demanding rapid and reliable analytical methods. Considering a growing number of papers presented in the last years in the field of capillary electrophoresis (CE) of DPs, this review article gives an overview on CE techniques which are feasible for the determination of DPs with the advantages of using relatively simple and inexpensive research instrumentation, reduced consumption of potentially toxic samples, shorter sample preparation times, etc. A brief introduction is provided into the chemical background of CWAs followed by a documented appraisal that the CE method is well suited to deal with polar, acidic DPs mostly occurring in aqueous samples or extracts. Applications of CE to the separation of DPs are described, complemented by a critical discussion of the detection techniques, including mostly conductivity, laser-induced fluorescence, UV absorption and mass spectrometry. This review also includes actual development regarding the challenges of CE in analyses of different DPs from real samples, often avoided by in- and off-line pre-concentration techniques or the coupling of CE to selective detection methods. Special emphasis is placed on the miniaturised CE systems that have the potential of being before long developed into a field deployable and potentially disposable platform for routine DP monitoring in environmental samples. PMID:21858300

  19. Sensitive detection of C-reactive protein in serum by immunoprecipitation-microchip capillary gel electrophoresis.

    PubMed

    Herwig, Ela; Marchetti-Deschmann, Martina; Wenz, Christian; Rüfer, Andreas; Redl, Heinz; Bahrami, Soheyl; Allmaier, Günter

    2015-06-01

    Sepsis represents a significant cause of mortality in intensive care units. Early diagnosis of sepsis is essential to increase the survival rate of patients. Among others, C-reactive protein (CRP) is commonly used as a sepsis marker. In this work we introduce immune precipitation combined with microchip capillary gel electrophoresis (IP-MCGE) for the detection and quantification of CRP in serum samples. First high-abundance proteins (HSA, IgG) are removed from serum samples using affinity spin cartridges, and then the remaining proteins are labeled with a fluorescence dye and incubated with an anti-CRP antibody, and the antigen/antibody complex is precipitated with protein G-coated magnetic beads. After precipitation the complex is eluted from the beads and loaded onto the MCGE system. CRP could be reliably detected and quantified, with a detection limit of 25 ng/μl in serum samples and 126 pg/μl in matrix-free samples. The overall sensitivity (LOQ = 75 ng/μl, R(2) = 0.9668) of the method is lower than that of some specially developed methods (e.g., immune radiometric assay) but is comparable to those of clinically accepted ELISA methods. The straightforward sample preparation (not prone to mistakes), reduced sample and reagent volumes (including the antibodies), and high throughput (10 samples/3 h) are advantages and therefore IP-MCGE bears potential for point-of-care diagnosis. PMID:25778394

  20. Analysis of carbonaceous biomarkers with the Mars Organic Analyzer microchip capillary electrophoresis system: carboxylic acids.

    PubMed

    Stockton, Amanda M; Tjin, Caroline Chandra; Chiesl, Thomas N; Mathies, Richard A

    2011-01-01

    The oxidizing surface chemistry on Mars argues that any comprehensive search for organic compounds indicative of life requires methods to analyze higher oxidation states of carbon with very low limits of detection. To address this goal, microchip capillary electrophoresis (μCE) methods were developed for analysis of carboxylic acids with the Mars Organic Analyzer (MOA). Fluorescent derivatization was achieved by activation with the water soluble 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) followed by reaction with Cascade Blue hydrazide in 30 mM borate, pH 3. A standard containing 12 carboxylic acids found in terrestrial life was successfully labeled and separated in 30 mM borate at pH 9.5, 20 °C by using the MOA CE system. Limits of detection were 5-10 nM for aliphatic monoacids, 20 nM for malic acid (diacid), and 230 nM for citric acid (triacid). Polyacid benzene derivatives containing 2, 3, 4, and 6 carboxyl groups were also analyzed. In particular, mellitic acid was successfully labeled and analyzed with a limit of detection of 300 nM (5 ppb). Analyses of carboxylic acids sampled from a lava tube cave and a hydrothermal area demonstrated the versatility and robustness of our method. This work establishes that the MOA can be used for sensitive analyses of a wide range of carboxylic acids in the search for extraterrestrial organic molecules.

  1. Analysis of ecstasy tablets using capillary electrophoresis with capacitively coupled contactless conductivity detection.

    PubMed

    Porto, Suely K S S; Nogueira, Thiago; Blanes, Lucas; Doble, Philip; Sabino, Bruno D; do Lago, Claudimir L; Angnes, Lúcio

    2014-11-01

    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.

  2. Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser-induced fluorescence detector.

    PubMed

    Liu, Cuicui; Fang, Guozhen; Deng, Qiliang; Zhang, Yan; Feng, Jingjing; Wang, Shuo

    2012-05-01

    A capillary electrophoresis immunoassay (CEIA) was developed for the determination of trace metolcarb (MTMC) in food. The method was based on the competitive reactions between fluorescently labeled MTMC tracer and free MTMC with a limited amount of anti-MTMC antibody and the separation and determination by CE with LIF detector. A fluorescent reagent, FITC was labeled on MTMC to construct an immunofluorescent probe. CEIA experimental parameters such as the pH value and concentration of the running buffer and separation voltage as well as incubation time were systematically investigated. Under the optimized conditions, fluorescently labeled antigen and antibody bound could be well separated within 3 min using Na₂B₄O₇/NaH₂PO₄ buffer (20:10 mmol/L, pH 9.0) for background electrolyte, 20 kV for the separation voltage, and 20°C for the column temperature. The linear range of the method was 0.25-50.0 μg/L with LOD 0.07 μg/L. The RSD for relative migration time and relative fluorescence intensity ratio were 2.90% (intraday) and 4.73% (intraday), respectively. The proposed method has been applied to determine the residue of MTMC in food samples with the satisfactory recovery. PMID:22648817

  3. Rapid simultaneous determination of organic acids, free amino acids, and lactose in cheese by capillary electrophoresis.

    PubMed

    Izco, J M; Tormo, M; Jiménez-Flores, R

    2002-09-01

    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).

  4. [Simultaneous separation and determination of vanillin and o-vanillin by capillary zone electrophoresis].

    PubMed

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

    2010-11-01

    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.

  5. Determination of gentisin, isogentisin, and amarogentin in Gentiana lutea L. by capillary electrophoresis.

    PubMed

    Citová, Ivana; Ganzera, Markus; Stuppner, Hermann; Solich, Petr

    2008-01-01

    A novel, fast, and simple capillary electrophoresis method has been developed for the analysis of gentisin, isogentisin, and amarogentin in roots of Gentiana lutea (yellow gentian), an herb traditionally used as gastric stimulant. Gentisin and isogentisin are xanthones showing potent inhibition of monoamine oxidase type A and B, amarogentin represents one of the bitter principles of Gentiana, responsible for its gastric-roborant effects. Optimal CE-separation conditions comprise a 100 mM sodium tetraborate buffer of pH 9.3, containing 10 mM beta-cyclodextrin as additive; optimum temperature and applied voltage were found to be 30 degrees C and 25 kV, respectively. Direct diode array detection at 260 nm (gentisin, isogentisin) and 242 nm (amarogentin) was performed, and the required analysis time was only 11 min. The developed method was validated for linearity, sensitivity, precision, and accuracy, and utilized to assay several commercially available G. lutea samples. Quantitative data obtained with the developed CE method are compared with HPLC results, and the advantages of each approach are discussed.

  6. Capillary electrophoresis-mass spectrometry as a new approach to analyze neonicotinoid insecticides.

    PubMed

    Sánchez-Hernández, Laura; Hernández-Domínguez, Deamelys; Bernal, José; Neusüß, Christian; Martín, María T; Bernal, José L

    2014-09-12

    This paper represents the first report of a capillary electrophoresis (CE) method compatible with mass spectrometry (MS) detection for simultaneously analyzing seven neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid and thiamethoxam). Different variables affecting CE separation (buffer concentration, pH, applied voltage and injection time) and MS detection (electrospray parameters) were studied. Low limits of detection (LOD) and quantification (LOQ) were achieved for all analytes, ranging from 1.0 to 2.3μg/L, and from 3.5 to 7.2μg/L, respectively. In addition, the proposed method showed itself to be linear in the range from LOQ to 1000μg/L and to be precise, as the relative standard deviations of the migration times were lower than 4% in all cases. Finally, the proposed CE-MS method was applied to assess the efficacy of a beeswax cleaning treatment with oxalic acid to remove residues of three of the most commonly used neonicotinoids (clothianidin, imidacloprid and thiamethoxam), use of which has recently been restricted by the European Union. PMID:25085817

  7. Identification and differentiation of Cryptosporidium species by capillary electrophoresis single-strand conformation polymorphism.

    PubMed

    Power, Michelle L; Holley, Marita; Ryan, Una M; Worden, Paul; Gillings, Michael R

    2011-01-01

    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. PMID:21087296

  8. Determination of L-ascorbic acid in Lycopersicon fruits by capillary zone electrophoresis.

    PubMed

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

    2001-09-15

    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.

  9. Separation of linear synthetic polymers in non-aqueous capillary zone electrophoresis using cationic surfactant.

    PubMed

    Yamamura, Tomoyuki; Kitagawa, Shinya; Ohtani, Hajime

    2015-05-01

    A method for separating water-insoluble and neutral synthetic polymers using non-aqueous capillary zone electrophoresis (NACZE) was developed. The non-aqueous solvent system comprising a mixture of tetrahydrofuran, acetonitrile, and ethanol containing cetyltrimethylammonium chloride was used for solubilizing and conferring positive charges to the polymers. A mixture of polystyrene (PS, Mn=6500) and polybutadiene (PBD, Mn=5900) was successfully separated by the NACZE method using cationic surfactants. Evaluation of the effect of the molecular weight of the polymers on the electrophoretic behavior demonstrated that PSs with different molecular weights (Mn=6500, 10,200, 19,600, 200,000) were co-eluted as a single peak. That is, the apparent electrophoretic mobility of the PSs was independent of the molecular weight. In contrast, evaluation of PBD and polycarbonate (PC) demonstrated that the solubility of polymers in the medium affected the apparent electrophoretic mobility of the polymers, where low solubility resulted in reduced apparent electrophoretic mobility. Using the proposed method, poly(styrene-co-methylmethacrylate)s with different compositions were successfully separated. PMID:25828544

  10. Analysis of degradation products of chemical warfare agents using capillary electrophoresis.

    PubMed

    Aleksenko, Svetlana S; Gareil, Pierre; Timerbaev, Andrei R

    2011-10-21

    Analysis of chemical warfare agents (CWAs), their precursors and degradation products (DPs) is an important verification component in support of the Chemical Weapons Convention and urgently demanding rapid and reliable analytical methods. Considering a growing number of papers presented in the last years in the field of capillary electrophoresis (CE) of DPs, this review article gives an overview on CE techniques which are feasible for the determination of DPs with the advantages of using relatively simple and inexpensive research instrumentation, reduced consumption of potentially toxic samples, shorter sample preparation times, etc. A brief introduction is provided into the chemical background of CWAs followed by a documented appraisal that the CE method is well suited to deal with polar, acidic DPs mostly occurring in aqueous samples or extracts. Applications of CE to the separation of DPs are described, complemented by a critical discussion of the detection techniques, including mostly conductivity, laser-induced fluorescence, UV absorption and mass spectrometry. This review also includes actual development regarding the challenges of CE in analyses of different DPs from real samples, often avoided by in- and off-line pre-concentration techniques or the coupling of CE to selective detection methods. Special emphasis is placed on the miniaturised CE systems that have the potential of being before long developed into a field deployable and potentially disposable platform for routine DP monitoring in environmental samples.

  11. [Determination of amino acids in honey by capillary electrophoresis with indirect ultraviolet detection].

    PubMed

    Zhou, Xianjing; Shi, Yanping

    2013-07-01

    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.

  12. [Determination of major metal cations in juices and nectars by capillary zone electrophoresis].

    PubMed

    Malinkin, A D; Bessonov, V V; Shumakova, A A; Arianova, E A; Prokof'eva, V I

    2014-01-01

    The method of determination of potassium, sodium, calcium and magnesium cations by capillary zone electrophoresis (using lithium cations as the internal standard) in the juices and nectars was advised. Optimal conditions for electrophoretic separation: pH value of the working buffer (pH 3.6), the concentration of imidazole (contrast agent 15-20 mmol/dm3), the concentration of 18-crown-6 ether (2 mmol/dm3). The method was tested on 15 samples of juices and nectars. The results of determination of potassium and magnesium cations were compared with results obtained by mass spectrometry with inductively coupled plasma. The equation of the linear regression and R-squared value for determinations of magnesium cations were defined as: y = 0.999x + 3.29; R = 0.952; for determination of potassium cations: y = 0.959x + 51.94; R = 0.997; indicating good the correlation between the data obtained by these methods.

  13. Analysis of ecstasy tablets using capillary electrophoresis with capacitively coupled contactless conductivity detection.

    PubMed

    Porto, Suely K S S; Nogueira, Thiago; Blanes, Lucas; Doble, Philip; Sabino, Bruno D; do Lago, Claudimir L; Angnes, Lúcio

    2014-11-01

    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. PMID:25039689

  14. Recent advances in sheathless interfacing of capillary electrophoresis and electrospray ionization mass spectrometry.

    PubMed

    Zamfir, Alina D

    2007-08-01

    On line sheathless capillary electrophoresis (CE)-electrospray ionization (ESI) mass spectrometry is developing as a powerful method in bioanalytics as it provides high resolution, sensitivity, relatively short analysis times, and amenability to a wide class of compounds. However, unlike the popular nano liquid chromatography (nano LC) or sheath-flow CE/ESI-MS, the sheathless coupling lacks standardized designs and protocols. For this reason, sheathless CE/ESI is a subject of conceptual and technical upgrading more than any other liquid-based separation method hyphenated to MS. Here, recent innovations in sheathless CE/ESI-MS interfacing are gathered in a survey covering the 2005/2006 period. In the first part of the review, the current concepts and methods for in-laboratory production of sturdy designs based on either conductive emitters or electrodeless interfaces are described. The second part is dedicated to microchip CE platforms with externally connected emitters for sheathless coupling to ESI-MS and advanced microfluidic devices integrating CE and sheathless electrospray in a single chip substrate. The advantages, limitations and feasibility for certain applications of all these systems as well as the perspectives for their performance improvement are concurrently assessed.

  15. Rapid determination of nonaromatic organic acids in honey by capillary zone electrophoresis with direct ultraviolet detection.

    PubMed

    Mato, Inés; Huidobro, José F; Simal-Lozano, Jesús; Sancho, M Teresa

    2006-03-01

    A rapid capillary zone electrophoresis (CZE) method with direct ultraviolet (UV) detection has been set up and developed to determine the most important nonaromatic organic acids in honey with a really simple treatment of the sample. The determination of oxalic, formic, malic, succinic, pyruvic, acetic, lactic, citric, and gluconic acids has been carried out in 4 min. The electrolyte composition was phosphate as the carrier buffer (7.5 mM NaH(2)PO(4) and 2.5 mM Na(2)HPO(4)), 2.5 mM tetradecyltrimethylammonium hydroxide (TTAOH) as electroosmotic flow modifier, and 0.24 mM CaCl(2) as selectivity modifier, with the pH adjusted at 6.40 constant value. The running voltage was -25 kV at a thermostated temperature of 25 degrees C. The injections were performed in hydrodynamic mode (30 s), and the detection mode was UV direct at 185 nm. Validation parameters of the method as detection and quantification limits, linearity, precision (repeatability and reproducibility), and recovery were also studied. The advantages related to the technique such as simplicity, short analysis times, and low consumption of chemicals as well as the good validation parameters obtained for this method permit it to be considered as adequate for routine analysis in honey.

  16. Comparative study between capillary electrophoresis and high performance liquid chromatography in 'guarana' based phytopharmaceuticals.

    PubMed

    Sombra, Lorena L; Gómez, María R; Olsina, Roberto; Martínez, Luis D; Silva, María F

    2005-01-01

    The last years have seen a significant increase in the use of herbal medicines and their preparations all over the world. Adulterations with synthetic drugs are common problems with phytopharmaceutical products and this can potentially cause adverse effects. In consequence, it is important to determine the presence of synthetic drugs in herbal medicines to ensure their efficacy and safety. In this study, guarana derivatives were analyzed by capillary electrophoresis (CE), and the results were compared with those obtained by the HPLC technique. In order to obtain adequate fingerprints, and search for adulterants, caffeine was used as the marker compound. This separation method was applied to analyze the seed powder and commercial tablets of Paulinia cupana Mart. The methodology performance was evaluated in terms of specificity, sensitivity and precision. The results are in agreement with those obtained by the HPLC method. Furthermore, the analysis time of the CE method is up to two times shorter than the respective parameter in HPLC and solvent consumption is more than 100-fold less.

  17. Sensitive detection of C-reactive protein in serum by immunoprecipitation-microchip capillary gel electrophoresis.

    PubMed

    Herwig, Ela; Marchetti-Deschmann, Martina; Wenz, Christian; Rüfer, Andreas; Redl, Heinz; Bahrami, Soheyl; Allmaier, Günter

    2015-06-01

    Sepsis represents a significant cause of mortality in intensive care units. Early diagnosis of sepsis is essential to increase the survival rate of patients. Among others, C-reactive protein (CRP) is commonly used as a sepsis marker. In this work we introduce immune precipitation combined with microchip capillary gel electrophoresis (IP-MCGE) for the detection and quantification of CRP in serum samples. First high-abundance proteins (HSA, IgG) are removed from serum samples using affinity spin cartridges, and then the remaining proteins are labeled with a fluorescence dye and incubated with an anti-CRP antibody, and the antigen/antibody complex is precipitated with protein G-coated magnetic beads. After precipitation the complex is eluted from the beads and loaded onto the MCGE system. CRP could be reliably detected and quantified, with a detection limit of 25 ng/μl in serum samples and 126 pg/μl in matrix-free samples. The overall sensitivity (LOQ = 75 ng/μl, R(2) = 0.9668) of the method is lower than that of some specially developed methods (e.g., immune radiometric assay) but is comparable to those of clinically accepted ELISA methods. The straightforward sample preparation (not prone to mistakes), reduced sample and reagent volumes (including the antibodies), and high throughput (10 samples/3 h) are advantages and therefore IP-MCGE bears potential for point-of-care diagnosis.

  18. Evaluation of Fluorescent Capillary Electrophoresis for Rapid Identification of Candida Fungal Infections.

    PubMed

    Obručová, Hana; Tihelková, Radka; Kotásková, Iva; Růžička, Filip; Holá, Veronika; Němcová, Eva; Freiberger, Tomáš

    2016-05-01

    Early diagnosis of fungal infection is critical for initiating antifungal therapy and reducing the high mortality rate in immunocompromised patients. In this study, we focused on rapid and sensitive identification of clinically important Candida species, utilizing the variability in the length of the ITS2 rRNA gene and fluorescent capillary electrophoresis (f-ITS2-PCR-CE). The method was developed and optimized on 29 various Candida reference strains from which 26 Candida species were clearly identified, while Candida guilliermondii, C. fermentati, and C. carpophila, which are closely related, could not be distinguished. The method was subsequently validated on 143 blinded monofungal clinical isolates (comprising 26 species) and was able to identify 88% of species unambiguously. This indicated a higher resolution power than the classical phenotypic approach which correctly identified 73%. Finally, the culture-independent potential of this technique was addressed by the analysis of 55 retrospective DNA samples extracted directly from clinical material. The method showed 100% sensitivity and specificity compared to those of the combined results of cultivation and panfungal PCR followed by sequencing used as a gold standard. In conclusion, this newly developed f-ITS2-PCR-CE analytical approach was shown to be a fast, sensitive, and highly reproducible tool for both culture-dependent and culture-independent identification of clinically important Candida strains, including species of the "psilosis" complex.

  19. Concurrent determination of anions and cations in consumer fireworks with a portable dual-capillary electrophoresis system.

    PubMed

    Sáiz, Jorge; Duc, Mai Thanh; Koenka, Israel Joel; Martín-Alberca, Carlos; Hauser, Peter C; García-Ruiz, Carmen

    2014-11-01

    A new automated portable dual-channel capillary electrophoresis instrument was built and applied to the concurrent determination of cations and anions. The system uses a single buffer and hydrodynamic injection of the sample is performed autonomously. A novel engraved flow-cell interface is used at the injection ends of the capillaries allowing the autonomous operation of the system. The engraved flow-cell replaces traditionally used split injectors in purpose made capillary electrophoresis systems and makes the system design easier. A new software package with graphical user interface was employed to control the system, making its operation simple and increasing its versatility. The electrophoretic method was optimized to allow the baseline separation of 12 cations and anions commonly found in fireworks. The system was proven to be useful for the analysis of consumer fireworks, saving time and expenses compared to separate analyses for anions and cations. This is the first time that cationic and anionic compositions of fireworks are investigated together. The analysis of samples revealed several inaccuracies between the declared compositions for the fireworks and the obtained results, which could be attributed to cross-contamination during their manufacture or to a transfer between other components of the pyrotechnic item. The presence of certain unexpected peaks, however, had no apparent reason and might represent an irregularity in the manufacture of some devices.

  20. Concurrent determination of anions and cations in consumer fireworks with a portable dual-capillary electrophoresis system.

    PubMed

    Sáiz, Jorge; Duc, Mai Thanh; Koenka, Israel Joel; Martín-Alberca, Carlos; Hauser, Peter C; García-Ruiz, Carmen

    2014-11-01

    A new automated portable dual-channel capillary electrophoresis instrument was built and applied to the concurrent determination of cations and anions. The system uses a single buffer and hydrodynamic injection of the sample is performed autonomously. A novel engraved flow-cell interface is used at the injection ends of the capillaries allowing the autonomous operation of the system. The engraved flow-cell replaces traditionally used split injectors in purpose made capillary electrophoresis systems and makes the system design easier. A new software package with graphical user interface was employed to control the system, making its operation simple and increasing its versatility. The electrophoretic method was optimized to allow the baseline separation of 12 cations and anions commonly found in fireworks. The system was proven to be useful for the analysis of consumer fireworks, saving time and expenses compared to separate analyses for anions and cations. This is the first time that cationic and anionic compositions of fireworks are investigated together. The analysis of samples revealed several inaccuracies between the declared compositions for the fireworks and the obtained results, which could be attributed to cross-contamination during their manufacture or to a transfer between other components of the pyrotechnic item. The presence of certain unexpected peaks, however, had no apparent reason and might represent an irregularity in the manufacture of some devices. PMID:25465022

  1. Is capillary electrophoresis on microchip devices able to genotype uridine diphosphate glucuronosyltransferase 1A1 TATA-box polymorphisms?

    PubMed

    Minucci, Angelo; Canu, Giulia; De Bonis, Maria; Delibato, Elisabetta; Capoluongo, Ettore

    2014-06-01

    In this commentary, we focused our attention on capillary electrophoresis. It achieves the efficient separation of molecular species by the application of high voltages to samples in solution. Actually, capillary electrophoresis can be performed on microchip devices, based on an automated and miniaturized electrophoresis system, based on lab-on-a-chip technology. By this technology it is possible to separate nucleic acid fragments (DNA or RNA) with respect to sizing accuracy and sizing resolution. Currently, two automated capillary electrophoresis on microchips devices are available: the Agilent 2100 Bioanalyzer and the Experion™ Automated Electrophoresis System. In this study, we evaluated if the CE is able to distinguish the three uridine diphosphate glucuronosyltransferase 1A1 TATA-box genotypes.

  2. On-line simultaneous and rapid separation of anions and cations from a single sample using dual-capillary sequential injection-capillary electrophoresis.

    PubMed

    Gaudry, Adam J; Guijt, Rosanne M; Macka, Mirek; Hutchinson, Joseph P; Johns, Cameron; Hilder, Emily F; Dicinoski, Greg W; Nesterenko, Pavel N; Haddad, Paul R; Breadmore, Michael C

    2013-06-01

    A novel capillary electrophoresis (CE) approach has been developed for the simultaneous rapid separation and identification of common environmental inorganic anions and cations from a single sample injection. The method utilised a sequential injection-capillary electrophoresis instrument (SI-CE) with capacitively-coupled contactless conductivity detection (C(4)D) constructed in-house from commercial-off-the-shelf components. Oppositely charged analytes from a single sample plug were simultaneously injected electrokinetically onto two separate capillaries for independent separation and detection. Injection was automated and may occur from a syringe or be directly coupled to an external source in a continuous manner. Software control enabled high sample throughput (17 runs per hour for the target analyte set) and the inclusion of an isolation valve allowed the separation capillaries to be flushed, increasing throughput by removing slow migrating species as well as improving repeatability. Various environmental and industrial samples (subjected only to filtering) were analysed in the laboratory with a 3 min analysis time which allowed the separation of 23 inorganic and small organic anions and cations. Finally, the system was applied to an extended automated analysis of Hobart Southern Water tap water for a period of 48 h. The overall repeatability of the migration times of a 14 analyte standard sample was less than 0.74% under laboratory conditions. LODs ranged from 5 to 61 μg L(-1). The combination of automation, high confidence of peak identification, and low limits of detection make this a useful system for the simultaneous identification of a range of common inorganic anions and cations for discrete or continuous monitoring applications.

  3. Investigation of the in vitro biotransformation and simultaneous enantioselective separation of thalidomide and its neutral metabolites by capillary electrophoresis.

    PubMed

    Weinz, C; Blaschke, G

    1995-12-15

    Reversed-phase liquid chromatography is a long established method for the analysis of drug metabolism. The current investigation demonstrates that micellar electrokinetic capillary chromatography can be an attractive alternative. Two methods were developed using sodium dodecyl sulfate and hexadecyltrimethylammonium bromide for the determination of possible hydroxylated metabolites of the former sedative drug thalidomide (Contergan) in order to study the in vitro metabolism of the drug by incubation with rat liver microsomes. The biotransformation was found to be stereoselective: S-(-)-thalidomide mainly formed 5-hydroxythalidomide, whereas R-(+)-thalidomide was preferentially transformed to two metabolites tentatively assigned to be diastereomers of 5'-hydroxythalidomide. Furthermore, the simultaneous enantioseparation of thalidomide and two of its possible hydroxylated metabolites was achieved using capillary electrophoresis with negatively charged carboxymethyl-beta-cyclodextrin. The dependencies of the selectivity of the enantioseparation on the concentration of the chiral additive and the pH of the run buffer were investigated. PMID:8788158

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

    SciTech Connect

    Chang, H.T.

    1994-07-27

    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.

  5. Use of a Hepta-tyr glycopeptide antibiotic as chiral selector in capillary electrophoresis.

    PubMed

    Fanali, S; Aturki, Z; Desiderio, C; Bossi, A; Righetti, P G

    1998-07-01

    A new glycopeptide antibiotic, MDL 63,246 (Hepta-tyr), of the teicoplanin family, has been evaluated in capillary electrophoresis for the resolution of chiral compounds of pharmaceutical and environmental interest. Electrophoretic separations were carried out in a polyacrylamide-coated capillary using the partial filling-counter current mode with aqueous-organic buffers in the pH range 4-6. Experimental parameters affecting resolution, such as antibiotic concentration, buffer pH, organic modifier type and capillary temperature, were studied. The Hepta-tyr antibiotic exhibited a high enantiorecognition capability towards the studied compounds at very low concentrations (1-2 mg/mL). The optimum experimental conditions were achieved by using a buffer at pH 5 containing acetonitrile at 25 degrees C.

  6. Capillary electrophoresis analysis of a wide variety of seized drugs using the same capillary with dynamic coatings.

    PubMed

    Lurie, Ira S; Hays, Patrick A; Parker, Kimberly

    2004-06-01

    Capillary electrophoresis methodology is presented for the routine analysis of a wide variety of seized drugs using the same capillary with dynamic coatings and multiple run buffers. The types of exhibits analyzed using diode array UV detection include phenethylamines, cocaine, oxycodone, heroin, lysergic acid diethylamide (LSD), opium, hallucinogenic mushrooms, and gamma-hydroxybutyrate-gamma-butyrolactone (GHB-GBL). Both qualitative and quantitative analyses are achieved using run buffers that contain additives that provide for secondary equilibrium and/or dynamic coating of the capillary. Dynamic coating of the capillary surface is accomplished by rapid flushes of 0.1 N sodium hydroxide, water, buffer containing polycation coating reagent, and a buffer containing a polyanionic coating reagent (with or without cyclodextrin(s)) or a micelle coating reagent. Dynamic coating with a polyanionic coating reagent is used for the analysis of moderately basic seized drugs and adulterants. The use of cyclodextrin in the run buffer not only allows for chiral analysis but also greatly enhances separation selectivity for achiral solutes. A capillary dynamically coated with a micelle allows for the analysis of neutral, acidic, and weakly basic drugs (GHB, GBL and neutral, acidic, and weakly basic adulterants). Dynamic coating, which gives rise to a relatively high and robust electroosmotic flow at pH < 7, allows for rapid, precise and reproducible separations. For a wide variety of drugs, excellent linearity and migration time precision and good peak area precision (external and internal standard) is obtained. Quantitative results for synthetic mixtures are in good agreement with actual values. Screening for adulterants is greatly enhanced by the use of automated library searches.

  7. [Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis].

    PubMed

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

    2014-04-01

    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.

  8. Functionalization and characterization of persistent luminescence nanoparticles by dynamic light scattering, laser Doppler and capillary electrophoresis.

    PubMed

    Ramírez-García, Gonzalo; d'Orlyé, Fanny; Gutiérrez-Granados, Silvia; Martínez-Alfaro, Minerva; Mignet, Nathalie; Richard, Cyrille; Varenne, Anne

    2015-12-01

    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.

  9. Functionalization and characterization of persistent luminescence nanoparticles by dynamic light scattering, laser Doppler and capillary electrophoresis.

    PubMed

    Ramírez-García, Gonzalo; d'Orlyé, Fanny; Gutiérrez-Granados, Silvia; Martínez-Alfaro, Minerva; Mignet, Nathalie; Richard, Cyrille; Varenne, Anne

    2015-12-01

    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. PMID:26409685

  10. Highly sensitive wavelength-dependent nonaqueous capillary electrophoresis for simultaneous screening of various synthetic organic dyes.

    PubMed

    Park, Moonhee; Bahng, Seung-Hoon; Woo, Nain; Kang, Seong Ho

    2016-05-15

    A novel multi-wavelength nonaqueous capillary electrophoresis (MW-NACE) technique based on wavelength-dependent laser-induced fluorescence (LIF) detection was investigated for the simultaneous screening of various synthetic organic dyes. Multi-wavelength excitation light sources were utilized to excite different organic dyes [e.g., 543 nm for crystal violet (CV), methyl violet B (MVB), methyl violet B base (MBB), rhodamine 6G (R6G), and rhodamine B base (RBB); 635 nm for nile blue A (NBA) and methylene blue (MB)] simultaneously. Using a nonaqueous buffer system composed of 15 mM sodium borate and 835 mM acetic acid in 100% ethanol (pH=5.4), all dyes were analyzed within 15 min with excellent resolution (R≥4.0) under an electric field of 500 V/cm. Calibration curves showed excellent linearity with square of correlation coefficients (r(2)) greater than 0.9908 over wide dynamic ranges of 0.4-50 μM for CV, 0.8-50 μM for MVB, 1.5-50 μM for MBB, 0.08-5 nM for R6G, 0.06-10 μM for MB, 0.02-10 μM for NBA, and 0.13-10 pM for RBB. The detection limits (S/N=3) of 40 fM to 0.5 μM were 10-200,000 times lower than those of previous detection methods. While adjacent peaks were not well distinguished with baseline separation in a single capillary, the devised technique was faster and more sensitive than conventional aqueous and nonaqueous CE approaches, thereby enabling the quantitative analysis of various dyes based on wavelength-dependent fluorescence detection with different excitation wavelengths. PMID:26992516

  11. Iodine speciation in biological samples by capillary electrophoresis-inductively coupled plasma mass spectrometry.

    PubMed

    Michalke, B; Schramel, P

    1999-09-01

    A hyphenation of capillary electrophoresis (CE) to inductively coupled plasma mass spectrometry (ICP-MS) was employed for the speciation of iodine. The separation method used a buffer sandwich of phosphate (pH 2.3), NaOH, sodium dodecyl sulfate (SDS) and borate buffer (pH 8.3) for stacking, aiming at sufficient separation of iodide, iodate, thyroxine (T4) and triiodothyronine (T3). These four iodine species were separated within 15 min and subsequently detected during a pressure-driven detection step (baseline-separated) at 19.5, 29.1, 36.6 and 42.2 s. The detection limits were determined at 0.08 microg I/L (iodide), 0.3 microg I/L (iodate), 3.5 microg I/L (thyroxine) and 2.5 microg I/L (triiodothyronine). This method was applied on iodine speciation in human serum ("healthy" and after thyroid gland operation) and urine. The serum from the healthy person contained iodide (13 microg I/L), T4 (61 microg I/L) and T3 (7.5 microg I/L), whereas the serum from the thyroid-operated person lacked T3. As no "free" I-hormones are known in serum, the role of the thyroid hormone binding globulin (TBG) was investigated. We found that spiked T4 or T3 immediately bound to TBG. Investigations on human urine showed only a peak for iodide.

  12. Capillary electrophoresis-based immobilized enzyme reactor using particle-packing technique.

    PubMed

    Liu, Lina; Zhang, Bo; Zhang, Qian; Shi, Yanhong; Guo, Liping; Yang, Li

    2014-07-25

    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.

  13. [Determination of penicillin intermediate and three penicillins in milk by high performance capillary electrophoresis].

    PubMed

    Tian, Chunqiu; Tan, Huarong; Gao, Liping; Shen, Huqin; Qi, Kezong

    2011-11-01

    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.

  14. Development of a simplified microfluidic injector for analysis of droplet content via capillary electrophoresis.

    PubMed

    DeLaMarre, Michael F; Shippy, Scott A

    2014-10-21

    Droplet-based microfluidic platforms sequester nanoliter to picoliter samples in an immiscible carrier phase and have gained notoriety for their ability to be used in laboratory procedures on a miniaturized scale. Recently, droplet microfluidics has been used to prevent zone diffusion in time-resolved sample collection methods and in separation techniques. The assay of droplets remains challenging, however, because the carrier phase is often incompatible with separation techniques. In this work, we report the development of a droplet injector for capillary electrophoresis (CE) which delivers 750 pL droplets to a channel for separation while excluding the fluorous carrier phase. This design is simple compared to previous reports, consisting of only two straight channels and no additional working parts such as membranes or valves. To demonstrate a proof-of-concept and characterize performance, riboflavin was used as a biologically relevant model molecule. Droplets containing a step change in riboflavin concentration were injected and mobilized by CE. The current method is capable of riboflavin peak % relative standard deviations (RSDs) down to 4.4% and temporal resolutions down to 15 s. Human urine samples containing riboflavin and its photolysis products were successfully separated and found to be chemically compatible with the injector. Our simplified design could improve robustness and ruggedness and may allow device construction via nontraditional fabrication techniques.

  15. Determination of NTBC in serum samples from patients with hereditary tyrosinemia type I by capillary electrophoresis.

    PubMed

    Cansever, M Serif; Aktuğlu-Zeybek, A Ciğdem; Erim, F Bedia

    2010-03-15

    Hereditary tyrosinemia type I is a serious metabolic disorder leading to liver failure. 2-(2-Nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) is a relatively new drug which is used to prevent the accumulation of toxic metabolites in patients with hereditary tyrosinemia type I. In the present study, we have developed a new, simple, fast, and cost-effective capillary electrophoresis method for the quantitative monitoring of this drug in serum samples. Micellar electrochromatographic separation of NTBC was performed using 20 mmol/L phosphate and 40 mmol/L sodium dodecylsulfate (SDS) at pH 12 as running electrolyte. Separation of NTBC was achieved in around 4 min. Reproducibilities of migration times and corrected peak areas of NTBC (as R.S.D.%) were found as 0.73 and 1.99, respectively. The detection limit was 3.17 and the quantification limit was 10.6 micromol/L for NTBC using UV detection at 278 nm. The utility of the method was demonstrated by the detection of NTBC in serum samples from patients with hereditary tyrosinemia type I using this drug.

  16. Determination of five nitroimidazole residues in artificial porcine muscle tissue samples by capillary electrophoresis.

    PubMed

    Lin, Yingyun; Su, Yan; Liao, Xiulin; Yang, Na; Yang, Xiupei; Choi, Martin M F

    2012-01-15

    A capillary electrophoresis (CE) method with ultraviolet detection has been developed for simultaneous detection and quantification of five nitroimidazoles including benzoylmetronidazole, dimetridazole, metronidazole, ronidazole, and secnidazole in porcine muscles. Nitroimidazoles in samples were extracted by ethyl acetate with subsequent clean-up by a strong cation exchange solid phase extraction column. The clean extracts were subjected to CE separation with optimal experimental conditions: pH 3.0 running buffer containing 25mM sodium phosphate and 0.10mM tetrabutylammonium bromide, 5s hydrodynamic injection at 0.5psi and 28kV separation voltage. The nitroimidazoles could be monitored and detected at 320nm within 18min. The limits of detection were below 1.0μg/kg and limits of quantification were lower than 3.2μg/kg for all nitroimidazoles in the muscle samples. The recoveries and relative standard deviations were 85.4-96.0, 83.5-92.5, 1.3-3.9, and 1.1-4.2%, respectively for the intra-day and inter-day analyses. The proposed CE method has been successfully applied to determine nitroimidazoles in artificial porcine muscle samples with good accuracy and recovery, demonstrating that it has potential for detection and quantification of multi-nitroimidazole residue in real muscle samples. PMID:22265553

  17. Determination of the composition of Chinese ligustrum lucidum polysaccharide by capillary zone electrophoresis with amperometric detection.

    PubMed

    Wang, Qingjiang; Yu, Hui; Zong, Jun; He, Pingang; Fang, Yuzhi

    2003-03-10

    In this paper, capillary zone electrophoresis with amperometric detection was firstly applied to indirectly determine the composition of Chinese ligustrum lucidum polysaccharide (LLPS) by analyzing its hydrolyzates: fucose, glucose, arabinose and rhamnose. Under the selected optimum conditions, the four monosaccharides could be perfectly separated within 30 min and showed significant current responses at the copper electrode. The linear ranges of fucose, glucose and arabinose were all from 5.0 x 10(-6) to 1.0 x 10(-4) mol l(-1) and that of rhamnose was from 1.0 x 10(-5) to 1.0 x 10(-4) mol l(-1), and their detection limits were lower or near 1.0 x 10(-6) mol l(-1) (S/N=3). Experiments showed that the mole ratio of fucose, glucose, arabinose and rhamnose in Chinese LLPS was 1.80:4.58:2.55:1.91, and the purity of this polysaccharide leached by the introduced leaching method was 93.3%. Analyzing polysaccharide by this method has some merits of quickness, low-volume sampling, simple instrument, high sensitivity and high reproducibility. PMID:12615234

  18. Direct identification of all oncogenic mutants in KRAS exon 1 by cycling temperature capillary electrophoresis.

    PubMed

    Bjørheim, Jens; Gaudernack, Gustav; Giercksky, Karl-Erik; Ekstrøm, Per O

    2003-01-01

    Over the past few decades, advances in genetics and molecular biology have revolutionized our understanding of cancer initiation and progression. Molecular progression models outlining genetic events have been developed for many solid tumors, including colon cancer. Previous reports in the literature have shown a relationship between different KRAS mutations and prognosis and response to medical treatment in colon cancer patients. Furthermore, the presence of a mutated KRAS has been correlated with different clinicopathological variables including age and gender of patients and tumor location. To our knowledge, few institutions screen for KRAS mutations on regular basis in colon cancer patients despite such evidence that knowledge of KRAS exon 1 status is informative. Here, we report on a mutation analysis method adapted to a 96-capillary electrophoresis instrument that allows identification of all 12 oncogenic mutations in KRAS exon 1 under denaturing conditions. To determine the optimal parameters, a series of DNA constructs generated by site-directed mutagenesis was analyzed and the migration times of all mutant peaks were measured. A classification tree was then made based on the differences in migration time between the mutants and an internal standard. A randomized series of 500 samples constructed with mutagenesis as well as 60 blind samples from sporadic colon carcinomas was analyzed to test the method. No wild-type samples were scored as mutants and all mutants were correctly identified. Post polymerase chain reaction (PCR) analysis time of 96 samples was performed within 40 min. PMID:12652573

  19. A comparative study of capillary zone electrophoresis and pH-potentiometry for determination of dissociation constants.

    PubMed

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

    2007-09-01

    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.

  20. Capillary electrophoresis with electrospray ionisation-mass spectrometry for the characterisation of degradation products in aged papers.

    PubMed

    Dupont, Anne-Laurence; Seemann, Agathe; Lavédrine, Bertrand

    2012-01-30

    A methodology for capillary electrophoresis/electrospray ionisation mass spectrometry (CE/ESI-MS) was developed for the simultaneous analysis of degradation products from paper among two families of compounds: low molar mass aliphatic organic acids, and aromatic (phenolic and furanic) compounds. The work comprises the optimisation of the CE separation and the ESI-MS parameters for improved sensitivity with model compounds using two successive designs of experiments. The method was applied to the analysis of lignocellulosic paper at different stages of accelerated hygrothermal ageing. The compounds of interest were identified. Most of them could be quantified and several additional analytes were separated.