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Sample records for capillary electrochromatography-mass spectrometry

  1. Capillary electrochromatography-mass spectrometry of nonionic surfactants.

    PubMed

    Norton, Dean; Shamsi, Shahab A

    2007-12-15

    The Triton X (TX)-series are alkylphenol polyethoxylates -type nonionic surfactants of varying numbers of ethylene oxide units. Applications include industrial and household detergent formulations as well as emulsifying agents. For analysis of these surfactants, capillary electrochromatography-electrospray ionization-mass spectrometry (CEC-ESI-MS) offers several unique advantages over the traditional hyphenation methods based on HPLC-MS. These include higher plate numbers attainable in CEC-MS, as well as more compatible flow rate (submicroliter) when coupled to ESI-MS and, perhaps most importantly, less consumption of toxic and costly organic solvents. In this work, different CEC-ESI-MS parameters such as mobile-phase composition, sheath liquid, and spray chamber parameters were optimized to provide suitable and sensitive analysis of short-, medium-, and long-chain length (e.g., n = 1-16) TX-series nonionic surfactants. The optimized CEC-ESI-MS conditions were mobile phase containing 90/10 ACN/2.5 mM Tris, pH 8, sheath liquid containing 50/50 MeOH/10 mM HCO(2)NH(4) delivered at 5 microL/min, spray chamber set to drying gas flow of 6 mL/min, nebulizer pressure of 5 psi, and drying gas temperature set to 200 degrees C. This optimization is followed by the more challenging separation of very long chain TX-series with a large number (n = 30-70) of ethoxy units, which were initially found to exhibit extreme retention using the developed method. It was observed that through the addition of small volume fraction of polar-aprotic tetrahydrofuran solvent to the running buffer, the retention time could be significantly reduced thus enhancing the feasibility for CEC-ESI-MS analysis of these very long chain nonionic surfactants for the first time. The detection limit was approximately 37 microg/mL total octylphenol ethoxylate for TX-45; acceptable precision of migration time (<1% RSD, n = 3) and peak area ( approximately 4% RSD, n = 3) were achieved.

  2. Development of a Fritless Packed Column for Capillary Electrochromatography-Mass Spectrometry

    PubMed Central

    Bragg, William; Shamsi, Shahab A.

    2011-01-01

    A novel procedure was developed for the fabrication of a fritless packed column for the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS). The process involved the formation of internal tapers on two separate columns. Once the internal tapers are formed and the columns are packed, the untapered ends of each column were joined together by a commercially available connector. Several advantages of the fritless columns are described. First, the design used here eventually eliminates the need for any frits thus reducing the possibility of bubble formation seen with fritted packed columns. In addition, this is the first report in which the internal tapers are formed at both the inlet and outlet column ends making the fritless CEC-MS column more robust compared to only one report with externally tapered counterparts. Second, a comparison of internally tapered single frit packed CEC-MS (previously developed in our laboratory) column versus fritless CEC-MS column reported here shows that the latter provides better efficiency, suggesting no dead volume with equally good sensitivity and chiral resolution of (±)-aminoglutethimide. The fritless column procedure is universal and was used to prepare a series of columns with a variety of commercially available packing material (mixed mode strong cation exchange, SCX; mixed mode strong anion exchange, SAX; C-18) for the separation and MS detection of short chain non-chromophoric polar amines, long chain nonchromophic anionic surfactant as well as oligomers of non-chromophoric non-ionic surfactants, respectively. The fritless columns showed good intra-day repeatibility and inter-day reproducibility of retention times, chiral and achiral resolutions and peak areas. Very satisfactory column-to-column and operator-to-operator reproducibility was demonstrated. PMID:22035695

  3. Development of a fritless packed column for capillary electrochromatography-mass spectrometry.

    PubMed

    Bragg, William; Shamsi, Shahab A

    2011-12-02

    A novel procedure was developed for the fabrication of a fritless packed column for the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS). The process involved the formation of internal tapers on two separate columns. Once the internal tapers are formed and the columns are packed, the untapered ends of each column were joined together by a commercially available connector. Several advantages of the fritless columns are described. First, the design used here eventually eliminates the need for any frits thus reducing the possibility of bubble formation seen with fritted packed columns. In addition, this is the first report in which the internal tapers are formed at both the inlet and outlet column ends making the fritless CEC-MS column more robust compared to only one report with externally tapered counterparts. Second, a comparison of internally tapered single frit packed CEC-MS (previously developed in our laboratory) column versus fritless CEC-MS column reported here shows that the latter provides better efficiency, suggesting no dead volume with equally good sensitivity and chiral resolution of (±)-aminoglutethimide. The fritless column procedure is universal and was used to prepare a series of columns with a variety of commercially available packing material (mixed mode strong cation exchange, SCX; mixed mode strong anion exchange, SAX; C-18) for the separation and MS detection of short chain non-chromophoric polar amines, long chain nonchromophic anionic surfactant as well as oligomers of non-chromophoric non-ionic surfactants, respectively. The fritless columns showed good intra-day repeatability and inter-day reproducibility of retention times, chiral and achiral resolutions and peak areas. Very satisfactory column-to-column and operator-to-operator reproducibility was demonstrated. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Packed-column capillary electrochromatography and capillary electrochromatography-mass spectrometry using a lithocholic acid stationary phase

    PubMed Central

    Norton, Dean; Shamsi, Shahab A.

    2009-01-01

    The preparation and characterization of a novel lithocholic acid (LCA)-based liquid crystalline (LC) stationary phase (SP) suitable for application in packed-column CEC and CEC coupled to MS is described. The extent of bonding reactions of LCA-SP was assessed using 1H-NMR, 13C-NMR and elemental analysis. This characterization is followed by application of the LCA-SP for separation of β-blockers, phenylethylamines (PEAs), polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Using the optimum mobile phase operating conditions (pH 3.0-4.5, 10 mM ammonium acetate, 85% v/v ACN), a comparison of the chromatographic ability of the aminopropyl silica phase vs. the LCA-bonded phase was conducted. The results showed improved selectivity for all test analytes using the latter phase. For example, the CEC-MS of β-blockers demonstrated that the LCA-bonded phase provides separation of six out of seven β-blockers, whereas the amino silica phase provides four peaks of several co-eluting β-blockers. For the CEC-MS analysis of PEAs, the LCA-bonded phase showed improved resolution and different selectivity as compared to the aminopropyl phase. An evaluation of the retention trends for PEAs on both phases suggested that the PEAs were retained based on varying degree of hydroxyl substitution on the aromatic ring. In addition, the MS characterization shows several PEAs fragment in the electrospray either by loss of an alkyl group and/or by loss of H2O. Finally, the LCA-bonded phase displayed significantly higher separation selectivity for PAHs and PCBs as compared to the amino silica phase. PMID:18425746

  5. 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.

  6. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    DOEpatents

    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.

  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. Characterization of Microdialysis Acidification for Capillary Isoelectric Focusing Microelectrospray Ionization Mass Spectrometry

    SciTech Connect

    Yang, Liyu; Lee, Cheng S.; Hofstadler, Steven A. ); Smith, Richard D. )

    1998-01-01

    A microdialysis junction, based on a microdialysis membrane connecting a separate capillary and a short, sharply tapered microelectrospray emitter capillary, is demonstrated for on-line combination of capillary isoelectric focusing (CIEF) with electrospray ionization mass spectrometry (ESI-MS).

  9. Capillary electrophoresis-mass spectrometry of carbohydrates

    PubMed Central

    Zaia, Joseph

    2014-01-01

    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This review summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications. PMID:23386333

  10. Capillary electrophoresis-mass spectrometry of carbohydrates.

    PubMed

    Zaia, Joseph

    2013-01-01

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

  11. Capillary isoelectric focusing-electrospray mass spectrometry for protein analysis

    SciTech Connect

    Tang, Q.; Harrata, A.K.; Lee, C.S.

    1995-10-01

    On-line combination of capillary isoelectric focusing (CIEF) with electrospray mass spectrometry (ESMS) as a two-dimensional separation system is demonstrated. Mixtures of model proteins including cytochrome c (horse heart), myoglobin (horse heart), and carbonic anhydrase II (bovine erythrocyte) are focused and cathodically mobilized in a polyacrylamide-coated capillary. At the end of CIEF capillary, the mobilized protein zones are analyzed by mass spectrometry coupled on-line to an electrospray interface with a coaxial sheath flow configuration. The effects of carrier ampholyte concentration on the CIEF separation and the protein electrospray ionization mass spectra are presented and discussed. In this study, the focusing effect of CIEF permits analysis of very dilute protein samples. A typical concentration factor of 50-100 times is observed. The concentration detection limit of myoglobin for a full-scan CIEF-ESMS analysis is in the range of 10{sup -7} M, 2 orders of magnitude over that possible with normal capillary zone electrophoresis ESMS. 35 refs., 5 figs., 2 tabs.

  12. Solvent jet desorption capillary photoionization-mass spectrometry.

    PubMed

    Haapala, Markus; Teppo, Jaakko; Ollikainen, Elisa; Kiiski, Iiro; Vaikkinen, Anu; Kauppila, Tiina J; Kostiainen, Risto

    2015-03-17

    A new ambient mass spectrometry method, solvent jet desorption capillary photoionization (DCPI), is described. The method uses a solvent jet generated by a coaxial nebulizer operated at ambient conditions with nitrogen as nebulizer gas. The solvent jet is directed onto a sample surface, from which analytes are extracted into the solvent and ejected from the surface in secondary droplets formed in collisions between the jet and the sample surface. The secondary droplets are directed into the heated capillary photoionization (CPI) device, where the droplets are vaporized and the gaseous analytes are ionized by 10 eV photons generated by a vacuum ultraviolet (VUV) krypton discharge lamp. As the CPI device is directly connected to the extended capillary inlet of the MS, high ion transfer efficiency to the vacuum of MS is achieved. The solvent jet DCPI provides several advantages: high sensitivity for nonpolar and polar compounds with limit of detection down to low fmol levels, capability of analyzing small and large molecules, and good spatial resolution (250 μm). Two ionization mechanisms are involved in DCPI: atmospheric pressure photoionization, capable of ionizing polar and nonpolar compounds, and solvent assisted inlet ionization capable of ionizing larger molecules like peptides. The feasibility of DCPI was successfully tested in the analysis of polar and nonpolar compounds in sage leaves and chili pepper.

  13. 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.

  14. Capillary electrophoresis-mass spectrometry in food analysis.

    PubMed

    Simó, Carolina; Barbas, Coral; Cifuentes, Alejandro

    2005-04-01

    This work provides an updated overview (including works published till June 2004) on the principal applications of capillary electrophoresis-mass spectrometry (CE-MS) together with their main advantages and drawbacks in food science. Thus, analysis of amino acids, peptides, proteins, carbohydrates, or polyphenols by CE-MS in different foods is reviewed. Also, other natural compounds (e.g., alkaloids) and toxins analyzed by CE-MS in foods are revised. Moreover, exogenous substances with a potential risk for human health (e.g., pesticides, drugs) detected in foods by CE-MS are included in this work. The usefulness of CE-MS for food analysis and the information that this coupling can provide in terms of processing, composition, authenticity, quality, or safety of foods is also discussed.

  15. Fabrication of internally tapered capillaries for capillary electrochromatography electrospray ionization mass spectrometry.

    PubMed

    Zheng, Jack; Norton, Dean; Shamsi, Shahab A

    2006-02-15

    In this study, we report a novel procedure for fabricating internally tapered capillary columns suitable for the coupling of capillary electrochromatography (CEC) to electrospray mass spectrometry (ESI-MS). The internal tapers were prepared by slowly heating the capillary end in a methane/O2 flame. Due to continuous self-shrinking of the inner channel of the capillary, the inside diameter of the opening was reduced to 7-10 microm. The procedure is easy to handle, with no requirement for expensive equipment as well as elimination of problematic grinding of the tip. Several advantages of these new internal tapers, as compared to using externally tapered columns, are described. First, the problems of poor durability and tip breakage associated with external tapering were successfully overcome with the internal taper. A comparison of the online CEC/ESI-MS between external versus internal tapers showed that the latter provides enhanced electrospray stability, resulting in significantly lower short-term noise and very short-term noise values. In turn, the more rugged design of internal tapers allows performing CEC/MS utilizing a harsh polar organic mobile phase, which was not previously successful using an external taper due to higher operating current and electrospray arcing. Next, data on the reproducibility of the internally tapered CEC/MS column using warfarin and beta-blockers as model analytes are presented. For example, when comparing the reproducibility for separation of warfarin under reversed-phase conditions, the internal taper demonstrated superior intraday % RSD (1.6-3.4) as compared to the external taper intraday % RSD (5-6). Last, the applicability of performing quantitative CEC/MS with internally tapered capillaries is demonstrated for simultaneous enantioseparation of beta-blockers. Impressive quantitative results include good linearity of calibration curves (e.g., R2 = 0.9940-0.9988) and limit of detection as low as 30 nM. The sensitive detection of a

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. Numerical modeling of capillary electrophoresis - electrospray mass spectrometry interface design.

    PubMed

    Jarvas, Gabor; Guttman, Andras; Foret, Frantisek

    2015-01-01

    Capillary electrophoresis hyphenated with electrospray mass spectrometry (CE-ESI-MS) has emerged in the past decade as one of the most powerful bioanalytical techniques. As the sensitivity and efficiency of new CE-ESI-MS interface designs are continuously improving, numerical modeling can play important role during their development. In this review, different aspects of computer modeling and simulation of CE-ESI-MS interfaces are comprehensively discussed. Relevant essentials of hydrodynamics as well as state-of-the-art modeling techniques are critically evaluated. Sheath liquid-, sheathless-, and liquid-junction interfaces are reviewed from the viewpoint of multidisciplinary numerical modeling along with details of single and multiphase models together with electric field mediated flows, electrohydrodynamics, and free fluid-surface methods. Practical examples are given to help non-specialists to understand the basic principles and applications. Finally, alternative approaches like air amplifiers are also included. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 34: 558-569, 2015. © 2014 Wiley Periodicals, Inc.

  3. On-line capillary isoelectric focusing-electrospray mass spectrometry for protein characterization

    SciTech Connect

    Tang, Qing; Harrata, K.A.; Lee, C.S.

    1996-12-31

    The integration of capillary isoelectric focusing (CIEF) with electrospray mass spectrometry (ESMS) as a two-dimensional separation system for protein characterization will be presented. Mixtures of protein variants are focused and cathodically mobilized in a polyacrylamide coated capillary. At the end of CIEF capillary, the mobilized protein zones are analyzed by mass spectrometry coupled on-line to an electrospray interface with a coaxial sheath flow configuration. The effects of carrier ampholyte concentration on the CIEF separation and the protein electrospray mass spectra will be discussed. On-line CIEF-ESMS with superior resolving power, speed, and sensitivity will be demonstrated for the analysis of hemoglobin and glycoprotein variants.

  4. Interlaboratory study to evaluate the robustness of capillary electrophoresis-mass spectrometry for peptide mapping.

    PubMed

    Wenz, Christian; Barbas, Coral; López-Gonzálvez, Ángeles; Garcia, Antonia; Benavente, Fernando; Sanz-Nebot, Victoria; Blanc, Tim; Freckleton, Gordon; Britz-McKibbin, Philip; Shanmuganathan, Meera; de l'Escaille, Francois; Far, Johann; Haselberg, Rob; Huang, Sean; Huhn, Carolin; Pattky, Martin; Michels, David; Mou, Si; Yang, Feng; Neusuess, Christian; Tromsdorf, Nora; Baidoo, Edward E K; Keasling, Jay D; Park, SungAe Suhr

    2015-07-06

    A collaborative study on the robustness and portability of a capillary electrophoresis-mass spectrometry method for peptide mapping was performed by an international team, consisting of 13 independent laboratories from academia and industry. All participants used the same batch of samples, reagents and coated capillaries to run their assays, whereas they utilized the capillary electrophoresis-mass spectrometry equipment available in their laboratories. The equipment used varied in model, type and instrument manufacturer. Furthermore, different types of sheath-flow capillary electrophoresis-mass spectrometry interfaces were used. Migration time, peak height and peak area of ten representative target peptides of trypsin-digested bovine serum albumin were determined by every laboratory on two consecutive days. The data were critically evaluated to identify outliers and final values for means, repeatability (precision within a laboratory) and reproducibility (precision between laboratories) were established. For relative migration time the repeatability was between 0.05 and 0.18% RSD and the reproducibility between 0.14 and 1.3% RSD. For relative peak area repeatability and reproducibility values obtained were 3-12 and 9-29% RSD, respectively. These results demonstrate that capillary electrophoresis-mass spectrometry is robust enough to allow a method transfer across multiple laboratories and should promote a more widespread use of peptide mapping and other capillary electrophoresis-mass spectrometry applications in biopharmaceutical analysis and related fields.

  5. Combined capillary electrophoresis and electrospray ionization mass spectrometry

    SciTech Connect

    Smith, R.D.; Loo, J.A.; Edmonds, C.G.; Udseth, H.R.

    1990-07-01

    The development of new capillary electrophoresis (CE) methods provides a basis for the efficient manipulation and separation of subpicomole quantities of polypeptides and proteins. Recent advances in microscale methods, such as the demonstration of the tryptic digestion of low picomole quantities of proteins using the immobilized enzyme in small diameter packed reactor column, provide the basis for such further developments. The use of capillary (free solution) zone electrophoresis (CZE) for separation of proteins, and recent demonstrations of restriction mapping of large deoxyribonucleotides, has propelled potential CE applications into the realm of conventional electrophoresis, while adding the attributes of speed, relatively simple on-line detection, automation, and reduced sample requirements (10{sup {minus}17} {minus} 10 {sup {minus}13} mole). A literal explosion of ancillary methods for sample manipulation, derivatization, and detection as well as new methods of obtaining separation selectivity are being reported. Additionally, other CE formats are attracting increased interest, with the aim of exploiting the unique features of capillary isotachophoresis (CITP), capillary isoelectric focusing (CIEF), capillary electrokinetic chromatograpgy (CEC), and most recently, capillary polyacrylamide gel electrophoresis (CGE). As a result, there are concomitant and increasing demands upon detector sensitivity and information density.

  6. Enabling Quantitative Analysis in Ambient Ionization Mass Spectrometry: Internal Standard Coated Capillary Samplers

    PubMed Central

    Liu, Jiangjiang; Cooks, R. Graham; Ouyang, Zheng

    2013-01-01

    We describe a sampling method using glass capillaries for quantitative analysis of trace analytes in small volumes of complex mixtures (~1 μL) using ambient ionization mass spectrometry. The internal surface of a sampling glass capillary was coated with internal standard then used to draw liquid sample and so transfer both the analyte and internal standard in a single fixed volume onto a substrate for analysis. The internal standard was automatically mixed into the sample during this process and the volumes of the internal standard solution and sample are both fixed by the capillary volume. Precision in quantitation is insensitive to variations in length of the capillary, making the preparation of the sampling capillary simple and providing a robust sampling protocol. Significant improvements in quantitation accuracy were obtained for analysis of 1 μL samples using various ambient ionization methods. PMID:23731380

  7. Stimulation and release from neurons via a dual capillary collection device interfaced to mass spectrometry.

    PubMed

    Fan, Yi; Lee, Chang Young; Rubakhin, Stanislav S; Sweedler, Jonathan V

    2013-11-07

    Neuropeptides are cell to cell signaling molecules that modulate a wide range of physiological processes. Neuropeptide release has been studied in sample sizes ranging from single cells and neuronal clusters, to defined brain nuclei and large brain regions. We have developed and optimized cell stimulation and collection approaches for the efficient measurement of neuropeptide release from neuronal samples using a dual capillary system. The defining feature is a capillary that contains octadecyl-modified silica nanoparticles on its inner wall to capture and extract releasates. This collection capillary is inserted into another capillary used to deliver solutions that chemically stimulate the cells, with solution flowing up the inner capillary to facilitate peptide collection. The efficiency of peptide collection was evaluated using six peptide standards mixed in physiological saline. The extracted peptides eluted from these capillaries were characterized via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with low femtomole detection limits. Using the capillary collection system in small custom-fabricated culturing chambers, individual cultured neurons and neuronal clusters from the model animal Aplysia californica were stimulated with distinct neuronal secretagogues and the releasates were collected and characterized using MALDI-TOF MS.

  8. Polydopamine-functionalized poly(ether ether ketone) tube for capillary electrophoresis-mass spectrometry.

    PubMed

    Zhou, Wei; Zhang, Wenpeng; Liu, Yikun; Yu, Xinhong; Chen, Zilin

    2017-09-22

    Capillary electrophoresis-mass spectrometry (CE-MS) is a hyphenated technique that combines the advantages like low sample consumption, high separation efficiency, short analytical time in CE and high sensitivity, powerful molecular structure elucidation in MS. Polyimide-coated fused silica capillary has become the most dominant capillary for CE, but it suffers from swelling and aminolysis of polyimide coating when treated with organic solvents and alkaline buffer in the CE-MS interface in which the polyimide coating at the end of the capillary is exposed to the solution, and this phenomenon can result in current instability, irregular electrospray and clogging at outlet after prolonged use. In this work, poly(ether ether ketone) (PEEK) capillary was explored as separation capillary for CE-MS. The problems like swelling and aminolysis of polyimide coating were solved due to the high thermal and chemical stability of PEEK material. After modification with polydopamine, PEEK capillary (PD-PEEK) can generate adjustable electroosmotic flow and provide good separation selectivity. The zwitterion polymer of polydopamine can provide cathodic electroosmotic flow (EOF) at high pH value (pH ≥ 5) and anodic EOF at low pH value (pH ≤ 4), and the EOF mobility can also be adjusted by controlling the modification time of polydopamine. Good separation performance was obtained in the analysis for several classes of compounds including amino acids, phenols and plant hormones at rational EOF direction. Repeatability of the PD-PEEK capillary was studied, with relative standard deviations for intra-day, inter-day runs and between tubes less than 4.94%. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Paper-capillary spray for direct mass spectrometry analysis of biofluid samples.

    PubMed

    Ren, Yue; Chiang, Spencer; Zhang, Wenpeng; Wang, Xiao; Lin, Ziqing; Ouyang, Zheng

    2016-02-01

    Paper spray has been developed as an ambient ionization method for direct analysis of biological samples using mass spectrometry. While distinct advantages of paper spray have been demonstrated, especially for quantitative analysis and design of disposable sample cartridges, the need for improvement has also been recognized, especially for the use with miniature mass spectrometers. In this study, we made an improvement to the sampling and ionization by adding a capillary emitter to the paper substrate to produce a paper-capillary spray, which has been shown to have significant, positive impact on the sensitivity and reproducibility for direct mass spectrometry analysis. The paper-capillary devices were fabricated and the effects of the geometry, the treatment of the capillary emitters, as well as the sample disposition methods were characterized. The method's analytical performance was also characterized for analysis of therapeutic drugs in blood samples. Quantitation of cotinine in blood using a commercial triple quadrupole and sitagliptin (Januvia®) in blood using a desktop Mini 12 ion trap mass spectrometer was also demonstrated.

  10. Capillary electrophoresis and mass spectrometry for screening of metabolic disorders in newborns.

    PubMed

    Senk, Petr; Kozák, Libor; Foret, Frantisek

    2004-06-01

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

  11. Improved electrospray ionization interface for capillary zone electrophoresis-mass spectrometry

    SciTech Connect

    Smith, R.D.; Barinaga, C.J.; Udseth, H.R.

    1988-09-15

    A new electrospray ionization interface for capillary zone electrophoresis-mass spectrometry (CZE-MS) is described. The interface uses a sheath flow of liquid to make the electrical contact at the CZE terminus, thus defining both the CZE and electrospray field gradients. This allows the composition of the electrosprayed liquid to be controlled independently of the CZE buffer, providing operation with buffers that could not be used previously (e.g., aqueous and high ionic strength buffers). The interface operation is independent of CZE flow rate; CZE capillaries are easily replaced and require no additional preparation. Since the electrospray occurs directly from the CZE capillary terminus, additional mixing volumes and metal surfaces are avoided and electrophoretic separation efficiency appears unperturbed. The dead volume associated with the electrospray interface is < 10 nL, corresponding to < 0.1 s for typical flow rates of the sheath electrode liquid. CZE-MS separations for mixtures of quaternary phosphonium salts and for epinephrine and related amines are demonstrated. Operation is demonstrated with high surfactant concentrations, as required for capillary electrokinetic chromatography. The extension to other capillary electrophoresis methods, such as isotachophoresis and isoelectric focusing, appears feasible.

  12. Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2006-07-01

    A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS.

  13. Increased Ion Transmission for Differential Ion Mobility Combined with Mass Spectrometry by Implementation of a Flared Inlet Capillary

    NASA Astrophysics Data System (ADS)

    Campbell, Matthew T.; Glish, Gary L.

    2017-01-01

    Differential ion mobility spectrometry (DIMS) is capable of separating components of complex mixtures prior to mass spectrometric analysis, thereby increasing signal-to-noise and signal-to-background ratios on millisecond timescales. However, adding a DIMS device to the front end of a mass spectrometer can reduce the signal intensity of subsequent mass spectrometric analysis. This is a result, in part, of ions lost due to inefficient transfer of ions from the DIMS device through the aperture leading into the mass spectrometer. This problem of transferring ions can be at least partially corrected by modifying the front end of the inlet capillary leading to the vacuum of the mass spectrometer. The inner diameter of the ion-sampling end of the inlet capillary was enlarged by drilling into the face. This results in a conical flare at the front end of the capillary, while the other end of the capillary remains unmodified. These flared capillaries allow for a greater number of ions from the DIMS device to be sampled relative to the unmodified standard capillary. Four flare dimensions were tested, differing by the angle between the wall of the flare and the outer wall of the inlet capillary. All flared capillaries showed greater signal intensity than the standard capillary with a DIMS device present without reducing the resolving power. It was also observed that the signal intensity increased as the flare angle decreased. The flared capillary with the smallest flare angle showed greater than a fivefold increase in signal intensity compared with the standard capillary.

  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.

  15. Biases in ion transmission through an electrospray ionization – mass spectrometry capillary inlet

    PubMed Central

    Page, Jason S.; Marginean, Ioan; Baker, Erin S.; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

    2010-01-01

    A heated capillary inlet for an electrospray ionization mass spectrometry (ESI-MS) interface was compared with shorter versions of the inlet to determine the effects on transmission and ionization efficiencies for low-flow (nano) electrosprays. Five different inlet lengths were studied, ranging from 6.4 to 1.3 cm. As expected, the electrospray current transmission efficiency increased with decreasing capillary length due to reduced losses to the inside walls of the capillary. This increase in transmission efficiency with shorter inlets was coupled with reduced desolvation of electrosprayed droplets. Surprisingly, as the inlet length was decreased, some analytes showed little or no increase in sensitivity, while others showed as much as a15 – fold gain. The variation was shown to beat least partially correlated with analyte mobilities, with the largest gains observed for higher mobility species, but also affected by solution conductivity, flow rate, and inlet temperature. Strategies for maximizing sensitivity while minimizing biases in ion transmission through the heated capillary interface are proposed. PMID:19815425

  16. Capillary Isoelectric Focusing-Mass Spectrometry of Proteins and Protein Complexes

    SciTech Connect

    Martinovic, Suzana; Pasa-Tolic, Liljiana; Smith, Richard D.

    2004-10-01

    Complex proteome samples require efficient separation and detection methods in order to characterize their protein components. On-line combination of capillary isoelectric focusing (CIEF) with electrospray ionization (ESI) mass spectrometry (MS) is shown as an effective method to analyze complex protein mixtures. Our experience with several microorganisms allowed us to establish successful experimental protocol. Here we use the example of E. coli whole cell lysate for the CIEF separation and MS detection on the intact protein level. The protocol was further adapted for the analysis of the mixture of non-covalent complexes on the intact complex level.

  17. Effects of Different Waveforms on the Performance of Active Capillary Dielectric Barrier Discharge Ionization Mass Spectrometry.

    PubMed

    Dumlao, Morphy C; Xiao, Dan; Zhang, Daming; Fletcher, John; Donald, William A

    2017-04-01

    Active capillary dielectric barrier discharge ionization (DBDI) is emerging as a compact, low-cost, and robust method to form intact ions of small molecules for detection in near real time by portable mass spectrometers. Here, we demonstrate that by using a 10 kHz, ~2.5 kVp-p high-voltage square-wave alternating current plasma, active capillary DBDI can consume less than 1 μW of power. In contrast, the power consumed using a sine and triangle alternating current waveform is more than two orders of magnitude higher than that for the square waveform to obtain a similar voltage for plasma generation. Moreover, the plasma obtained using a square waveform can be significantly more homogenous than that obtained using sine and triangle waveforms. Protonated dimethyl methylphosphonate (DMMP) and deprotonated perfluorooctanoic acid (PFOA) can be detected at about the same or higher abundances using square-wave DBDI mass spectrometry compared with the use of sine and triangle waveforms. By use of benzylammonium thermometer ions, the extent of internal energy deposition using square, sine, or triangle waveform excited plasmas are essentially the same at the optimum voltages for ion detection. Using an H-bridge circuit driving a transformer optimized to reduce losses, square-wave active capillary DBDI can be continuously powered for ~50 h by common 9 V-battery (PP3). Graphical Abstract ᅟ.

  18. Effects of Different Waveforms on the Performance of Active Capillary Dielectric Barrier Discharge Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Dumlao, Morphy C.; Xiao, Dan; Zhang, Daming; Fletcher, John; Donald, William A.

    2017-04-01

    Active capillary dielectric barrier discharge ionization (DBDI) is emerging as a compact, low-cost, and robust method to form intact ions of small molecules for detection in near real time by portable mass spectrometers. Here, we demonstrate that by using a 10 kHz, 2.5 kVp-p high-voltage square-wave alternating current plasma, active capillary DBDI can consume less than 1 μW of power. In contrast, the power consumed using a sine and triangle alternating current waveform is more than two orders of magnitude higher than that for the square waveform to obtain a similar voltage for plasma generation. Moreover, the plasma obtained using a square waveform can be significantly more homogenous than that obtained using sine and triangle waveforms. Protonated dimethyl methylphosphonate (DMMP) and deprotonated perfluorooctanoic acid (PFOA) can be detected at about the same or higher abundances using square-wave DBDI mass spectrometry compared with the use of sine and triangle waveforms. By use of benzylammonium thermometer ions, the extent of internal energy deposition using square, sine, or triangle waveform excited plasmas are essentially the same at the optimum voltages for ion detection. Using an H-bridge circuit driving a transformer optimized to reduce losses, square-wave active capillary DBDI can be continuously powered for 50 h by common 9 V-battery (PP3).

  19. Analysis of Proteins, Protein Complexes, and Organellar Proteomes Using Sheathless Capillary Zone Electrophoresis - Native Mass Spectrometry.

    PubMed

    Belov, Arseniy M; Viner, Rosa; Santos, Marcia R; Horn, David M; Bern, Marshall; Karger, Barry L; Ivanov, Alexander R

    2017-09-05

    Native mass spectrometry (MS) is a rapidly advancing field in the analysis of proteins, protein complexes, and macromolecular species of various types. The majority of native MS experiments reported to-date has been conducted using direct infusion of purified analytes into a mass spectrometer. In this study, capillary zone electrophoresis (CZE) was coupled online to Orbitrap mass spectrometers using a commercial sheathless interface to enable high-performance separation, identification, and structural characterization of limited amounts of purified proteins and protein complexes, the latter with preserved non-covalent associations under native conditions. The performance of both bare-fused silica and polyacrylamide-coated capillaries was assessed using mixtures of protein standards known to form non-covalent protein-protein and protein-ligand complexes. High-efficiency separation of native complexes is demonstrated using both capillary types, while the polyacrylamide neutral-coated capillary showed better reproducibility and higher efficiency for more complex samples. The platform was then evaluated for the determination of monoclonal antibody aggregation and for analysis of proteomes of limited complexity using a ribosomal isolate from E. coli. Native CZE-MS, using accurate single stage and tandem-MS measurements, enabled identification of proteoforms and non-covalent complexes at femtomole levels. This study demonstrates that native CZE-MS can serve as an orthogonal and complementary technique to conventional native MS methodologies with the advantages of low sample consumption, minimal sample processing and losses, and high throughput and sensitivity. This study presents a novel platform for analysis of ribosomes and other macromolecular complexes and organelles, with the potential for discovery of novel structural features defining cellular phenotypes (e.g., specialized ribosomes). Graphical Abstract ᅟ.

  20. Analysis of Proteins, Protein Complexes, and Organellar Proteomes Using Sheathless Capillary Zone Electrophoresis - Native Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Belov, Arseniy M.; Viner, Rosa; Santos, Marcia R.; Horn, David M.; Bern, Marshall; Karger, Barry L.; Ivanov, Alexander R.

    2017-09-01

    Native mass spectrometry (MS) is a rapidly advancing field in the analysis of proteins, protein complexes, and macromolecular species of various types. The majority of native MS experiments reported to-date has been conducted using direct infusion of purified analytes into a mass spectrometer. In this study, capillary zone electrophoresis (CZE) was coupled online to Orbitrap mass spectrometers using a commercial sheathless interface to enable high-performance separation, identification, and structural characterization of limited amounts of purified proteins and protein complexes, the latter with preserved non-covalent associations under native conditions. The performance of both bare-fused silica and polyacrylamide-coated capillaries was assessed using mixtures of protein standards known to form non-covalent protein-protein and protein-ligand complexes. High-efficiency separation of native complexes is demonstrated using both capillary types, while the polyacrylamide neutral-coated capillary showed better reproducibility and higher efficiency for more complex samples. The platform was then evaluated for the determination of monoclonal antibody aggregation and for analysis of proteomes of limited complexity using a ribosomal isolate from E. coli. Native CZE-MS, using accurate single stage and tandem-MS measurements, enabled identification of proteoforms and non-covalent complexes at femtomole levels. This study demonstrates that native CZE-MS can serve as an orthogonal and complementary technique to conventional native MS methodologies with the advantages of low sample consumption, minimal sample processing and losses, and high throughput and sensitivity. This study presents a novel platform for analysis of ribosomes and other macromolecular complexes and organelles, with the potential for discovery of novel structural features defining cellular phenotypes (e.g., specialized ribosomes). [Figure not available: see fulltext.

  1. Interface-free capillary electrophoresis-mass spectrometry system with nanospray ionization-Analysis of dexrazoxane in blood plasma.

    PubMed

    Tycova, Anna; Vido, Marek; Kovarikova, Petra; Foret, Frantisek

    2016-09-30

    The newly developed interface-free capillary electrophoresis-nanospray/mass spectrometry system (CE-nESI/MS) was applied for rapid analysis of the cardioprotective drug dexrazoxane and its hydrolysed form ADR-925 in deproteinized blood plasma samples. The aim of this study was to test the simplest possible CE-nESI/MS instrumentation for analyses of real samples. This interface-free system, utilizing single piece of a narrow bore capillary as both the electrophoretic separation column and the nanospray emitter, was operated at a flow rate of 30nL/min. Excellent electrophoretic separation and sensitive nanospray ionization was achieved with the use of only one high voltage power supply. In addition, hydrophobic external coating was developed and tested for additional stability of the nanospray ionization. To our knowledge this is the first study devoted to the analysis of dexrazoxane and ADR-925 by capillary electrophoresis-mass spectrometry.

  2. DETERMINATION OF CHLORINATED ACID HERBICIDES AND RELATED COMPOUNDS IN WATER BY CAPILLARY ELECTROPHORESIS-ELECTROSPRAY NEGATIVE ION MASS SPECTROMETRY

    EPA Science Inventory

    Capillary electrophoresis electrospray negative ion mass spectrometry was investigated for the determination of chlorinated acid herbicides and several phenols in water. Sixteen analytes were separated as their anions in less than 40 min with a buffer consisting of 5 mM ammonium ...

  3. Development of a liquid-junction/low-flow interface for phosphate buffer capillary electrophoresis mass spectrometry.

    PubMed

    Li, Fu-An; Huang, Ju-Li; Shen, Shang-Yu; Wang, Che-Wei; Her, Guor-Rong

    2009-04-01

    To alleviate ion suppression from phosphate buffer and to preserve separation integrity, a new capillary electrophoresis mass spectrometry (CE-MS) interface was developed. The interface consisted of a low-flow interface and a liquid junction. In this design, both the inlet reservoir and the liquid-junction reservoir were filled with phosphate running buffer. Because the phosphate anions in the column migrated toward the inlet reservoir (away from the electrospray ionization (ESI) source) the problem of ion suppression in ESI was avoided. The liquid junction was incorporated to eliminate issues of degraded separation observed when sheath liquid interfaces use different buffers for separation and MS analysis attributed to differences in anion velocity. The utility of the interface was demonstrated by the analysis of antihistamines at pH 3.5 and the analysis of perfluorocarboxylic acid at pH 9.5.

  4. Rapid and multi-level characterization of trastuzumab using sheathless capillary electrophoresis-tandem mass spectrometry

    PubMed Central

    Gahoual, Rabah; Burr, Alicia; Busnel, Jean-Marc; Kuhn, Lauriane; Hammann, Phillipe; Beck, Alain; François, Yannis-Nicolas; Leize-Wagner, Emmanuelle

    2013-01-01

    Monoclonal antibodies (mAbs) are highly complex proteins that display a wide range of microheterogeneity that requires multiple analytical methods for full structure assessment and quality control. As a consequence, the characterization of mAbs on different levels is particularly product - and time - consuming. This work presents the characterization of trastuzumab sequence using sheathless capillary electrophoresis (referred as CESI) – tandem mass spectrometry (CESI-MS/MS). Using this bottom-up proteomic-like approach, CESI-MS/MS provided 100% sequence coverage for both heavy and light chain via peptide fragment fingerprinting (PFF) identification. The result was accomplished in a single shot, corresponding to the analysis of 100 fmoles of digest. The same analysis also enabled precise characterization of the post-translational hot spots of trastuzumab, used as a representative widely marketed therapeutic mAb, including the structural confirmation of the five major N-glycoforms. PMID:23563524

  5. Utilization of capillary electrophoresis/mass spectrometry (CE/MSn) for the study of anthocyanin dyes.

    PubMed

    Bednár, Petr; Papousková, Barbora; Müller, Lukás; Barták, Petr; Stávek, Jan; Pavlousek, Pavel; Lemr, Karel

    2005-08-01

    Hyphenation of capillary electrophoresis with electrospray ionization mass spectrometry was utilized for the monitoring of anthocyanins in wine and wine musts. CE/MS was performed in two electrolytes: 1) an acidic one (chloroacetate-ammonium, pH 2) and 2) a basic one with high selectivity towards derivatives containing vicinal hydroxy groups (borate-ammonium, pH 9). The setup of MS was optimized and the fragmentation of common anthocyanins was studied in detail. Attention was also focused on the fragmentation of anthocyanidin skeleton. The anthocyanidins substituted with hydroxy groups fragment via a cascade of neutral losses of water and carbon monoxide. Fragmentation of anthocyanidins containing a methoxy group on their B-ring starts with the cleavage of methane and/or methyl radical. The optimized method was utilized for the monitoring of changes in anthocyanin profile in red wines as well as the process of release of anthocyanins to wine must.

  6. Qualitative and quantitative metabolomic investigation of single neurons by capillary electrophoresis electrospray ionization mass spectrometry

    PubMed Central

    Nemes, Peter; Rubakhin, Stanislav S.; Aerts, Jordan T.; Sweedler, Jonathan V.

    2013-01-01

    Single-cell mass spectrometry (MS) empowers metabolomic investigations by decreasing analytical dimensions to the size of individual cells and subcellular structures. We describe a protocol for investigating and quantifying metabolites in individual isolated neurons using single-cell capillary electrophoresis hyphenated to electrospray ionization time-of-flight MS. The protocol requires ~2 h for sample preparation, neuron isolation, and metabolite extraction, and 1 h for metabolic measurement. The approach was used to detect more than 300 distinct compounds in the mass range of typical metabolites in various individual neurons (25–500-µm in diameter) isolated from the sea slug (Aplysia californica) central and rat (Rattus norvegicus) peripheral nervous systems. A subset of identified compounds was sufficient to reveal metabolic differences among freshly isolated neurons of different types and changes in the metabolite profiles of cultured neurons. The protocol can be applied to the characterization of the metabolome in a variety of smaller cells and/or subcellular domains. PMID:23538882

  7. The selective determination of sulfates, sulfonates, and phosphates in urine by capillary electrophoresis/mass spectrometry.

    PubMed

    Bunz, Svenja-Catharina; Neusüß, Christian

    2013-01-01

    Metabolite identification and metabolite profiling are of major importance in the pharmaceutical and clinical context. However, anions of biological relevance such as sulfates, sulfonates, and phosphates are rarely included in common techniques for metabolite studies. In this protocol, we demonstrate a unique method to selectively determine these anions. The method comprises a capillary electrophoresis separation using an acidic background electrolyte (pH ≤ 2) and anodic detection by mass spectrometry via negative electrospray ionization. In this way, only anions of strong acids like sulfates are determined. The selectivity for sulfur-containing species is proved based on the specific isotopic ratios. In conjunction with the accurate mass from the time-of-flight mass spectrometer, the presented method is well suited for clinical and pharmaceutical applications to identify possible metabolites and to quantify known metabolites.

  8. Characterization of drug-lysozyme conjugates by sheathless capillary electrophoresis-time-of-flight mass spectrometry.

    PubMed

    Haselberg, R; Harmsen, S; Dolman, M E M; de Jong, G J; Kok, R J; Somsen, G W

    2011-07-18

    Drug-protein conjugates have been widely used for the cell-specific targeting of drugs to cells that can bind and internalize the proteinaceous carrier. For renal drug targeting, lysozyme (LZM) can be used as an effective carrier that accumulates in proximal tubular cells. We used capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF-MS) for the characterization of different drug-LZM conjugates. A recently developed prototype porous tip sprayer was employed for sheathless electrospray ionization (ESI) CE-MS interfacing. In order to prevent adsorption of LZM conjugates to the capillary wall, a positively charged polyethylenimine capillary coating was used in combination with a low-pH background electrolyte. Drug-LZM products had been prepared by first coupling BOC-l-methionine hydroxysuccinimide ester (BOCmet) to lysine residues of LZM followed by conjugation with the kinase inhibitors LY364947, erlotinib, or Y27632 via a platinum(II)-based linker. CE-TOF-MS of each preparation showed narrow symmetrical peaks for the various reaction products demonstrating that drug-LZM conjugates remained stable during the CE analysis and subsequent ESI. Components observed in the drug-LZM products were assigned based on their relative migration times and on molecular mass as obtained by TOF-MS. The TOF-MS data obtained for the individual components revealed that the preparations contained LZM carrying one or two drug molecules, next to unmodified and BOCmet-modified LZM. Based on relative peak areas (assuming an equimolar response for each component) a quantitative conjugate profile could be derived for every preparation leading to drug loading values of 0.4-0.6 mol drug per mole protein.

  9. Determination of cobalamins using capillary electrophoresis inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Baker, S. A.; Miller-Ihli, N. J.

    2000-12-01

    The determination of cobalamins using capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS) was investigated. Both capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) modes of operation were studied. The optimal separation of four cobalamin species (cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5'-deoxyadenosylcobalamin) and a potentially harmful corrinoid analogue (cobinamide dicyanide) was obtained using CZE at a pH of 2.5. Both 20 mM phosphate and 20 mM formate buffers were used with success, although the formate buffer provided improved resolution. The CZE-ICP-MS method was used to quantify cyanocobalamin in a vitamin supplement and the analytical results were in good agreement (±5%) with values obtained by ICP-MS for total Co levels. The solution detection limits for cobalamins using CZE-ICP-MS were approximately 50 ng/ml. MEKC was found to be useful for the screening of vitamin preparations because it provided a rapid means of distinguishing cyanocobalamin (the form most commonly used in vitamin preparations) from free cobalt. The separation of free cobalt and cyanocobalamin using MEKC was achieved in less than 10 min.

  10. 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

  11. High-resolution capillary isoelectric focusing-electrospray ionization mass spectrometry for hemoglobin variants analysis

    SciTech Connect

    Tang, Q.; Harrata, A.K.; Lee, C.S. |

    1996-08-01

    On-line capillary isoelectric focusing (CIEF)-electrospray ionization mass spectrometry (ESIMS) as a two-dimensional separation system is employed for high-resolution analysis of hemoglobin variants A, C, S, and F. The effects of moving ionic boundary inside the CIEF capillary and MS scan rate on the separation resolution and mass detection of hemoglobin variants are investigated. The formation of a moving ionic boundary due to the replacement of background electrolyte counterions with sheath liquid counterions can be minimized by combining cathodic mobilization with a gravity-induced hydrodynamic flow. Hemoglobin variants F and A, with a pI difference of 0.05 pH unit, are almost baseline resolved and identified in CIEF-ESIMS. The concentration detection limit for each hemoglobin variant is in the range of 10{sup -8} M, comparable to that obtained in two-dimensional gel electrophoresis using silver staining. Initial preconcentration during the focusing step and the use of single-ion monitoring scan mode are responsible for improving detection limits. 9 refs., 6 figs., 2 tabs.

  12. Analysis of anionic metallized azo and formazan dyes by capillary electrophoresis-mass spectrometry.

    PubMed

    Poiger, T; Richardson, S D; Baughman, G L

    2000-07-21

    Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cm x 50 microm uncoated fused-silica capillary and a 5 mM ammonium acetate buffer (pH 9) containing 40% acetonitrile. Excellent separation efficiencies (N = 500,000 plates/column) and low detection limits of 20-50 pg (selected ion monitoring, S/N = 10) were achieved. Mass spectra were acquired at different cone voltages. At low cone voltages (low collision energies), sensitivity was maximized and the mass spectra contained only signals of the (multiply charged) molecular ions and low levels of sodium ion and proton adducts. At higher cone voltages, the 2:1 (ligand:metal) chromium and cobalt dyes showed losses of one of the two dye ligands, accompanied by a reduction of the metal. The copper dyes showed signals due to loss of SO2 and SO3-, but no release of metal. Azo cleavage, otherwise typical of azo dyes, was not observed with the metallized dyes.

  13. Rapid level-3 characterization of therapeutic antibodies by capillary electrophoresis electrospray ionization mass spectrometry.

    PubMed

    Lew, Clarence; Gallegos-Perez, Jose-Luis; Fonslow, Bryan; Lies, Mark; Guttman, Andras

    2015-03-01

    With the increase of the number of approved protein therapeutics in the market, comprehensive and reproducible characterization of these new generation drugs is crucial for the biopharmaceutical industry and regulatory agencies. One of the largest groups of biotherapeutics is monoclonal antibodies (mABs) possessing various posttranslational modifications and potential degradation hotspots during the manufacturing process that may affect efficacy and immunogenicity. The exceptionally high separation power of capillary electrophoresis (CE) in conjunction with mass spectrometry fulfills Level-3 characterization requirements necessary to reveal such modifications and degradations. In this paper, a comprehensive characterization example will be given for a representative mAB Trastuzumab (Herceptin), illustrating the benefits of the integration of CE and electrospray ionization in a unified bioanalytical process coupled with high-resolution mass spectrometry. Peptides separated in a wide size range (3-65 amino acids) were identified with 100% sequence coverage and quantified, including degradative hotspots such as glutamic acid cyclization, methionine oxidation, aspargine deamidation and C-terminal lysine heterogeneity using only 100 fmol of a single protease digest sample. The low flow rate of the system (>20 nL/min) ensured maximized ionization efficiency and dramatically reduced ion suppression. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Multi-capillary column-ion mobility spectrometry of volatile metabolites emitted by Saccharomyces cerevisiae.

    PubMed

    Halbfeld, Christoph; Ebert, Birgitta E; Blank, Lars M

    2014-09-05

    Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption-gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism, fast and non-invasive MCC-IMS analyses provide valuable data for process control.

  15. Multi-Capillary Column-Ion Mobility Spectrometry of Volatile Metabolites Emitted by Saccharomyces Cerevisiae

    PubMed Central

    Halbfeld, Christoph; Ebert, Birgitta E.; Blank, Lars M.

    2014-01-01

    Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption–gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism, fast and non-invasive MCC-IMS analyses provide valuable data for process control. PMID:25197771

  16. Deamidation in ricin studied by capillary zone electrophoresis- and liquid chromatography-mass spectrometry.

    PubMed

    Bergström, Tomas; Fredriksson, Sten-Åke; Nilsson, Calle; Åstot, Crister

    2015-01-01

    Deamidation in ricin, a toxin present in castor beans from the plant Ricinus communis, was investigated using capillary zone electrophoresis (CZE) and liquid chromatography coupled to high resolution mass spectrometry. Potential sites for deamidation, converting asparagine (Asn) into aspartic or isoaspartic acid (Asp or isoAsp), were identified in silico based on the protein sequence motifs and tertiary structure. In parallel, CZE- and LC-MS-based screening were performed on the digested toxin to detect deamidated peptides. The use of CZE-MS was critical for the separation of small native/deamidated peptide pairs. Selected peptides were subjected to a detailed analysis by tandem mass spectrometry to verify the presence of deamidation and determine its exact position. In the ricin preparation studied, deamidation was confirmed and located to three asparagine residues: Asn54 in the A-chain, and Asn42 and Asn60 in the B-chain. Possible in vitro deamidation occurring during sample preparation was monitored using a synthetic peptide with a known and rapid rate of deamidation. Finally, we showed that the isoelectric diversity previously reported in ricin is related to the level of deamidation.

  17. Capillary electrochromatography and capillary electrochromatography-electrospray mass spectrometry for the separation of non-steroidal anti-inflammatory drugs.

    PubMed

    Desiderio, C; Fanali, S

    2000-10-20

    In this study capillary electrochromatography (CEC) was utilized for the separation of ten non-steroidal anti-inflammatory drugs (NSAIDs). Experiments were carried out in a commercially available CE instrument using a packed capillary with RP-18 silica particles where the stationary phase completely filled the capillary. The mobile phase consisted of a mixture of ammonium formate buffer pH 2.5 and acetonitrile. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the acetonitrile content mobile phase and the capillary temperature. The optimum experimental conditions for CEC separation of the studied drug mixture were found using 50 mM ammonium formate pH 2.5-acetonitrile (40:60) at 25 degrees C. The CEC capillary was coupled to an electrospray mass spectrometer for the characterization of the NSAIDs. A mobile phase composed by the same buffer but with a higher concentration of acetonitrile (90%) was used in order to speed up the separation of analytes.

  18. Accurate determination of peptide phosphorylation stoichiometry via automated diagonal capillary electrophoresis coupled with mass spectrometry: proof of principle.

    PubMed

    Mou, Si; Sun, Liangliang; Dovichi, Norman J

    2013-11-19

    While reversible protein phosphorylation plays an important role in many cellular processes, simple and reliable measurement of the stoichiometry of phosphorylation can be challenging. This measurement is confounded by differences in the ionization efficiency of phosphorylated and unphosphorylated sites during analysis by mass spectrometry. Here, we demonstrate diagonal capillary electrophoresis-mass spectrometry for the accurate determination of this stoichiometry. Diagonal capillary electrophoresis is a two-dimensional separation method that incorporates an immobilized alkaline phosphatase microreactor at the distal end of the first capillary and employs identical electrophoretic separation modes in both dimensions. The first dimension is used to separate a mixture of the phosphorylated and unphosphorylated forms of a peptide. Fractions are parked in the reactor where they undergo complete dephosphorylation. The products are then periodically transferred to the second capillary and analyzed by mass spectrometry (MS). Because the phosphorylated and unphosphorylated forms differ in charge, they are well resolved in the first dimension separation. Because the unphosphorylated and dephosphorylated peptides are identical, there is no bias in ionization efficiency, and phosphorylation stoichiometry can be determined by the ratio of the signal of the two forms. A calibration curve was generated from mixtures of a phosphorylated standard peptide and its unphosphorylated form, prepared in a bovine serum albumin tryptic digest. This proof of principle experiment demonstrated a linear response across nearly 2 orders of magnitude in stoichiometry.

  19. Peptide mapping using capillary electrophoresis offline coupled to matrix-assisted laser desorption ionization time of flight mass spectrometry.

    PubMed

    Bachmann, Stefan; Bakry, Rania; Huck, Christian W; Polato, Fabio; Corradini, Danilo; Bonn, Günther K

    2011-10-01

    This article reports the results of a study carried out to evaluate the offline hyphenation of capillary zone electrophoresis with matrix-assisted lased desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for the analysis of low-abundant complex samples, represented by the tryptic phosphorylated peptides of phosphoproteins, such as α-casein, β-casein, and fetuin. The proposed method employs a latex-coated capillary and consists in the online preconcentration of the tryptic peptides by a pH-mediated stacking method, their separation by capillary zone electrophoresis, and subsequent deposition of the separated analytes onto a MALDI target for their MS analysis. The online preconcentration method allows loading a large sample volume (∼150 nL), which is introduced into the capillary after the hydrodynamic injection of a short plug of 1.0 M ammonium hydroxide solution and is sandwiched between two plugs of the acidic background electrolyte solution (BGE) filling the capillary. The sample spotting of the separated analytes onto the MALDI target is performed either during or postseparation using an automatic spotting device connected to the exit of the separation capillary. The proposed method allows the separation and identification of multiphosphorylated peptides from other peptides and enables their identification at femtomole level with improved efficiency compared with LC approaches hyphenated to MS.

  20. Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Moini, Mehdi; Rollman, Christopher M.

    2016-03-01

    We introduce a battery operated capillary electrophoresis electrospray ionization (CE/ESI) source for mass spectrometry with optical isomer separation capability. The source fits in front of low or high resolution mass spectrometers similar to a nanospray source with about the same weight and size. The source has two high voltage power supplies (±25 kV HVPS) capable of operating in forward or reverse polarity modes and powered by a 12 V rechargeable lithium ion battery with operation time of ~10 h. In ultrafast CE mode, in which short narrow capillaries (≤15 μm i.d., 15-25 cm long) and field gradients ≥1000 V/cm are used, peak widths at the base are <1 s wide. Under these conditions, the source provides high resolution separation, including optical isomer resolution in ~1 min. Using a low resolution mass spectrometer (LTQ Velos) with a scan time of 0.07 s/scan, baseline separation of amino acids and their optical isomers were achieved in ~1 min. Moreover, bovine serum albumin (BSA) was analyzed in ~1 min with 56% coverage using the data-dependent MS/MS. Using a high resolution mass spectrometer (Thermo Orbitrap Elite) with 15,000 resolution, the fastest scan time achieved was 0.15 s, which was adequate for CE-MS analysis when optical isomer separation is not required or when the optical isomers were well separated. Figures of merit including a detection limit of 2 fmol and linear dynamic range of two orders of magnitude were achieved for amino acids.

  1. Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry.

    PubMed

    Moini, Mehdi; Rollman, Christopher M

    2016-03-01

    We introduce a battery operated capillary electrophoresis electrospray ionization (CE/ESI) source for mass spectrometry with optical isomer separation capability. The source fits in front of low or high resolution mass spectrometers similar to a nanospray source with about the same weight and size. The source has two high voltage power supplies (±25 kV HVPS) capable of operating in forward or reverse polarity modes and powered by a 12 V rechargeable lithium ion battery with operation time of ~10 h. In ultrafast CE mode, in which short narrow capillaries (≤15 μm i.d., 15-25 cm long) and field gradients ≥1000 V/cm are used, peak widths at the base are <1 s wide. Under these conditions, the source provides high resolution separation, including optical isomer resolution in ~1 min. Using a low resolution mass spectrometer (LTQ Velos) with a scan time of 0.07 s/scan, baseline separation of amino acids and their optical isomers were achieved in ~1 min. Moreover, bovine serum albumin (BSA) was analyzed in ~1 min with 56% coverage using the data-dependent MS/MS. Using a high resolution mass spectrometer (Thermo Orbitrap Elite) with 15,000 resolution, the fastest scan time achieved was 0.15 s, which was adequate for CE-MS analysis when optical isomer separation is not required or when the optical isomers were well separated. Figures of merit including a detection limit of 2 fmol and linear dynamic range of two orders of magnitude were achieved for amino acids.

  2. Fast determination of harmala alkaloids in edible algae by capillary electrophoresis mass spectrometry.

    PubMed

    Tascon, Marcos; Benavente, Fernando; Sanz-Nebot, Victoria M; Gagliardi, Leonardo G

    2015-05-01

    The use of algae as a foodstuff is rapidly expanding worldwide from the East Asian countries, where they are also used for medical care. Harmala alkaloids (HAlk) are a family of bioactive compounds found in the extracts of some plants, including wakame (Undaria pinnatifida), an edible marine invasive algae. HAlks are based on a characteristic β-carboline structure with at least one amino ionizable group. In this work, we report the successful separation of a mixture of six HAlks (harmine, harmaline, harmol, harmalol, harmane, and norharmane) by capillary electrophoresis ion-trap mass spectrometry (CE-IT-MS) in less than 8 min. Optimum separation in fused-silica capillaries and detection sensitivity in positive-ion mode were achieved using a background electrolyte (BGE) with 25 mmol L(-1) ammonium acetate (pH 7.8) and 10% (v/v) methanol, and a sheath liquid with 60:40 (v/v) isopropanol-water and 0.05% (v/v) formic acid. The separation method was validated in terms of linearity, limits of detection and quantification, repeatability, and reproducibility. Later, a sample pretreatment was carefully optimized to determine HAlks in commercial wakame samples with excellent recovery and repeatability. For the complex wakame extracts, the MS-MS fragmentation patterns of the different HAlks were useful to ensure a reliable identification. The complete procedure was validated using the standard-addition calibration method, determining matrix effects on the studied compounds. Harmalol, harmine, and harmaline were naturally present in the samples and were quantified at very low concentrations, ranging from 7 to 24 μg kg(-1) dry algae.

  3. Capillary electrophoresis-diode array detection--electrospray mass spectrometry for the analysis of selected tropane alkaloids in plant extracts.

    PubMed

    Mateus, L; Cherkaoui, S; Christen, P; Veuthey, J L

    1999-11-01

    Capillary zone electrophoresis, coupled to UV and interfaced with electrospray ionization mass spectrometry (ESI-MS), is described for the simultaneous analysis of hyoscyamine and scopolamine. On-line UV detection occurred at 22 cm from the inlet of the capillary and ESI-MS monitoring was performed along the entire length of the capillary (85 cm). An alkaline solution of 40 mM ammonium acetate at pH 8.5 was suitable for the analysis of the alkaloids under consideration. Under the optimized conditions, including CE and ESI-MS parameters, the two alkaloids were resolved within a short time and with very high sensitivity. The differentiation of hyoscyamine and its positional isomer littorine, commonly encountered in plant material, is also presented using up-front collision-induced dissociation. Finally, the developed method was applied to the analysis of these alkaloids in Belladonna leaf extract and in Datura candida x D. aurea hairy root extract.

  4. Screening of Small Intact Proteins by Capillary Electrophoresis Electrospray Ionization-Mass Spectrometry (CE-ESI-MS).

    PubMed

    Neuberger, Sabine; Rafai, Angelina; Neusüß, Christian

    2016-01-01

    Capillary electrophoresis (CE) has been shown to be a suitable separation technique for complex samples. Combined with electrospray ionization-mass spectrometry (ESI-MS), it is a powerful tool offering the opportunity of high selectivity and sensitivity combined with the possibility to identify and characterize intact proteins. In this protocol, we demonstrate a screening method for intact proteins based on capillary zone electrophoresis (CZE) separation coupled with online mass spectrometric detection. In order to avoid protein-wall interactions, a neutral coated capillary is used to create a universal method for proteins with both low and high electrophoretic mobilities. In addition, we show the successful validation and application of this screening method for a set of eight standard proteins and the glycoprotein erythropoietin.

  5. Recent advances in capillary electrophoresis coupled to mass spectrometry for clinical proteomic applications.

    PubMed

    Stalmach, Angelique; Albalat, Amaya; Mullen, William; Mischak, Harald

    2013-06-01

    Proteome analysis using capillary electrophoresis coupled to mass spectrometry (CE-MS) has been used in a number of clinical applications in the past years. The main focus of CE-MS-based studies has been on the investigation of urine, due to the stability of the urinary proteome, ease of collection, and also the low molecular weight range of the urinary proteome, mostly peptides below 30 kDa. The reproducibility of this approach has enabled analysis of over 20 000 samples in a comparable way, giving enormous statistical power to any additional study involving this methodological setup. In this article, we review the major technological issues associated with the application of CE-MS in the routine investigation of the urinary proteome for clinical applications. We pinpoint recent developments that may have a chance to improve on the currently used approach, and highlight obstacles that need to be solved. In the second part of the article, we review the recent clinical applications, aiming to highlight relevant issues, and possible future routine applications in clinical diagnosis. In the end, we provide a short outlook, and indicate future developments to be expected, as well as problems that need to be solved to enable routine application of CE-MS in a clinical setting.

  6. Multi-capillary-column proton-transfer-reaction time-of-flight mass spectrometry.

    PubMed

    Ruzsanyi, Veronika; Fischer, Lukas; Herbig, Jens; Ager, Clemes; Amann, Anton

    2013-11-05

    Proton-transfer-reaction time-of-flight mass-spectrometry (PTR-TOFMS) exhibits high selectivity with a resolution of around 5000 m/Δm. While isobars can be separated with this resolution, discrimination of isomeric compounds is usually not possible. The coupling of a multi-capillary column (MCC) with a PTR-TOFMS overcomes these problems as demonstrated in this paper for the ketone isomers 3-heptanone and 2-methyl-3-hexanone and for different aldehydes. Moreover, fragmentation of compounds can be studied in detail which might even improve the identification. LODs for compounds tested are in the range of low ppbv and peak positions of the respective separated substances show good repeatability (RSD of the peak positions <3.2%). Due to its special characteristics, such as isothermal operation, compact size, the MCC setup is suitable to be installed inside the instrument and the overall retention time for a complete spectrum is only a few minutes: this allows near real-time measurements in the optional MCC mode. In contrast to other methods that yield additional separation, such as the use of pre-cursor ions other than H3O(+), this method yields additional information without increasing complexity.

  7. Analysis of isoflavones in soy drink by capillary zone electrophoresis coupled with electrospray ionization mass spectrometry.

    PubMed

    Bustamante-Rangel, M; Delgado-Zamarreño, M M; Carabias-Martínez, R; Domínguez-Álvarez, J

    2012-01-04

    Capillary zone electrophoresis coupled with electrospray ionization mass spectrometry (CZE-ESI-MS) has been applied for the first time for the separation and quantification of isoflavones in soy products. The proposed method was successfully applied to the determination of seven isoflavones, including aglycones and glucosides, in soy drink. The target compounds were the glucosides daidzin and genistin, and the aglycones daidzein, genistein, formononetin, biochanin A and glycitein. During CE separation in positive mode, the analytes were present as anions, and MS detection was carried out in ESI positive-ion mode. To prevent the frequent drops in current and to improve the resolution in the separation of analytes in anionic form, a programmed nebulizing gas pressure (PNP) was applied along the analysis. Extraction of isoflavones from soy drinks was carried out by liquid-liquid extraction using ethanol. The proposed extraction procedure is simple, efficient, and affords reproducible results. Quantification of the isoflavones in soy drinks using the external standard method did not produce good results; therefore, both internal standard and standard addition quantification methods were used, obtaining significantly similar results. The detection limits found were lower than 3.2 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Characterization of microconcentric nebulizer uptake rates for capillary electrophoresis inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Yanes, Enrique G.; Miller-Ihli, Nancy J.

    2003-05-01

    There is demonstrated interest in combining capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICP-MS) for speciation determinations. When self-aspirating nebulizers are used for this application, it is important to offset the suction effect to avoid degradation of the separation. In this study, sample uptake rates for three microconcentric nebulizers of the same model, in combination with a cyclonic spray chamber, were characterized and compared for future utilization in CE-ICP-MS interfaces. The specific model studied was a MicroMist with a nominal uptake rate of 100 μl/min at 1 l/min argon gas flow rate per the manufacturer's specifications. Sample uptake rates at various nebulizer gas flows were measured by aspirating water from a weighed container and calculating the uptake rate in microliter per minute. The nebulizers studied provided good reproducibility from day to day, but a comparison of the different nebulizers reflected a significant difference in performance. A characteristic observed during the study was that uptake rates decreased with increasing nebulizer gas flow. This can be used for sample introduction for CE-ICP-MS. Interestingly, very different performance was observed when comparing the three different nebulizers of the same model. Uptake rates showed strong dependence on argon gas flow rates and the dimensions of the sample uptake tubing.

  9. Utilizing Microchip Capillary Electrophoresis Electrospray Ionization for Hydrogen Exchange Mass Spectrometry

    PubMed Central

    Black, William A.; Stocks, Bradley B.; Mellors, J. Scott; Engen, John R.; Ramsey, J. Michael

    2015-01-01

    Hydrogen exchange (HX) mass spectrometry (MS) of complex mixtures requires a fast, reproducible, and high peak capacity separation prior to MS detection. The current paradigm relies on liquid chromatography (LC) with fast gradients performed at low temperatures to minimize back exchange. Unfortunately, under these conditions, the efficiency of LC is limited due to resistance to mass transfer, reducing the capability to analyze complex samples. Capillary electrophoresis (CE), on the other hand, is not limited by resistance to mass transfer, enabling very rapid separations that are not adversely affected by low temperature. Previously, we have demonstrated an integrated microfluidic device coupling CE with electrospray ionization (ESI) capable of very rapid and high efficiency separations. In this work, we demonstrate the utility of this microchip CE-ESI device for HX MS. High speed CE-ESI of a bovine hemoglobin pepsin digestion was performed in 1 minute with a peak capacity of 62 versus a similar LC separation performed in 7 minutes with peak capacity of 31. A room temperature CE method performed in 1.25 minutes provided similar deuterium retention as an 8.5 minute LC method conducted at 0 °C. Separation of a complex mixture with CE was done with considerably better speed and nearly triple the peak capacity than the equivalent separation by LC. Overall the results indicate the potential utility of microchip CE-ESI for HX MS. PMID:25992468

  10. Capillary Electrophoresis-Mass Spectrometry for the Analysis of Heparin Oligosaccharides and Low Molecular Weight Heparin.

    PubMed

    Sun, Xiaojun; Lin, Lei; Liu, Xinyue; Zhang, Fuming; Chi, Lianli; Xia, Qiangwei; Linhardt, Robert J

    2016-02-02

    Heparins, highly sulfated, linear polysaccharides also known as glycosaminoglycans, are among the most challenging biopolymers to analyze. Hyphenated techniques in conjunction with mass spectrometry (MS) offer rapid analysis of complex glycosaminoglycan mixtures, providing detailed structural and quantitative data. Previous analytical approaches have often relied on liquid chromatography (LC)-MS, and some have limitations including long separation times, low resolution of oligosaccharide mixtures, incompatibility of eluents, and often require oligosaccharide derivatization. This study examines the analysis of glycosaminoglycan oligosaccharides using a novel electrokinetic pump-based capillary electrophoresis (CE)-MS interface. CE separation and electrospray were optimized using a volatile ammonium bicarbonate electrolyte and a methanol-formic acid sheath fluid. The online analyses of highly sulfated heparin oligosaccharides, ranging from disaccharides to low molecular weight heparins, were performed within a 10 min time frame, offering an opportunity for higher-throughput analysis. Disaccharide compositional analysis as well as top-down analysis of low molecular weight heparin was demonstrated. Using normal polarity CE separation and positive-ion electrospray ionization MS, excellent run-to-run reproducibility (relative standard deviation of 3.6-5.1% for peak area and 0.2-0.4% for peak migration time) and sensitivity (limit of quantification of 2.0-5.9 ng/mL and limit of detection of 0.6-1.8 ng/mL) could be achieved.

  11. Characterization of the mouse bronchoalveolar lavage proteome by micro-capillary LC–FTICR mass spectrometry

    SciTech Connect

    Pounds, Joel G.; Flora, Jason W.; Adkins, Joshua N.; Lee, Kyeonghee M.; Rana, Gaurav S.J.B.; Sengupta, Tapas; Smith, Richard D.; McKinney, Willie J.

    2008-03-15

    Bronchoalveolar lavage fluid (BALF) contains proteins derived from various pulmonary cell types, secretions and blood. As the characterization of the BALF proteome will be instrumental in establishing potential biomarkers of pathophysiology in the lungs, the objective of this study was to contribute to the comprehensive collection of Mus musculus BALF proteins using high resolution and highly sensitive micro-capillary liquid chromatography (microLC) combined with state-of-the-art high resolution mass spectrometry (MS). BALF was collected from ICR and C57BL/6 male mice exposed to nose-only inhalation to either air or cigarette smoke. The tandem mass spectra were analyzed by SEQUEST for peptide identifications with the subsequent application of accurate mass and time tags resulting in the identification of 1797 peptides with high confidence by high resolution MS. These peptides covered 959 individual proteins constituting the largest collection of BALF proteins to date. High throughput monitoring profiles of this extensive collection of BALF proteins will facilitate the discovery and validation of biomarkers that would elucidate pathogenic or adaptive responses of the lungs upon toxic insults.

  12. [Determination of arsenic speciation in Scomberomorus niphonius by capillary electrophoresis-inductively coupled plasma mass spectrometry].

    PubMed

    Chen, Fa-rong; Zheng, Li; Wang, Zhi-Guang; Sun, Jie; Han, Li-Hui; Wang, Xiao-ru

    2014-06-01

    A method for the detection of arsenocholine (AsC), arsenobetaine (AsB), As(III), dimethylarsinic (DMA), monomethylarsonic (MMA) and As (V) by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) was established. The results showed that the six species of arsenic were separated within 20 min under the optimized conditions. Good linearities of 6 arsenic species were observed in the range from 2 to 50 μg x L(-1) with the linear correlation greater than 0.996, the detection limits were 0.10-1.08 μg x L(-1) and the RSDs (n = 5) of the peak areas were smaller than 7%. The method was successfully adopted to the determination of the species in Scomberomorus niphonius. The recoveries were between 93% and 98%, and we found the arsenobetaine (AsB) was the main species in the sample. The method was suitable for the analysis of other biological samples with the advantages of good stability, less sample consumption, short analysis time and convenience.

  13. Discovery of regulatory molecular events and biomarkers using 2D capillary chromatography and mass spectrometry.

    PubMed

    Powell, David W; Merchant, Michael L; Link, Andrew J

    2006-02-01

    An important component of proteomic research is the high-throughput discovery of novel proteins and protein-protein interactions that control molecular events that contribute to critical cellular functions and human disease. The interactions of proteins are essential for cellular functions. Identifying perturbation of normal cellular protein interactions is vital for understanding the disease process and intervening to control the disease. A second area of proteomics research is the discovery of proteins that will serve as biomarkers for the early detection, diagnosis and drug treatment response for specific diseases. These studies have been referred to as clinical proteomics. To discover biomarkers, proteomics research employs the quantitative comparison of peptide and protein expression in body fluids and tissues from diseased individuals (case) versus normal individuals (control). Methods that couple 2D capillary liquid chromatography (LC) and tandem mass spectrometry (MS/MS) analysis have greatly facilitated this discovery science. Coupling 2D-LC/MS/MS analysis with automated genome-assisted spectra interpretation allows a direct, high-throughput and high-sensitivity identification of thousands of individual proteins from complex biological samples. The systematic comparison of experimental conditions and controls allows protein function or disease states to be modeled. This review discusses the different purification and quantification strategies that have been developed and used in combination with 2D-LC/MS/MS and computational analysis to examine regulatory protein networks and clinical samples.

  14. Microchip capillary electrophoresis-electrospray ionization-mass spectrometry of intact proteins using uncoated Ormocomp microchips.

    PubMed

    Sikanen, Tiina; Aura, Susanna; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2012-01-20

    We present rapid (<5 min) and efficient intact protein analysis by mass spectrometry (MS) using fully microfabricated and monolithically integrated capillary electrophoresis-electrospray ionization (CE-ESI) microchips. The microchips are fabricated fully of commercial inorganic-organic hybrid material, Ormocomp, by UV-embossing and adhesive Ormocomp-Ormocomp bonding (CE microchannels). A sheath-flow ESI interface is monolithically integrated with the UV-embossed separation channels by cutting a rectangular emitter tip in the end with a dicing saw. As a result, electrospray was produced from the corner of chip with good reproducibility between parallel tips (stability within 3.8-9.2% RSD). Thanks to its inherent biocompatibility and stable (negative) surface charge, Ormocomp microchips enable efficient intact protein analysis with up to ∼10(4) theoretical separation plates per meter without any chemical or physical surface modification before analysis. The same microchip setup is also feasible for rapid peptide sequencing and mass fingerprinting and shows excellent migration time repeatability from run to run for both peptides (5.6-5.9% RSD, n=4) and intact proteins (1.3-7.5% RSD, n=3). Thus, the Ormocomp microchips provide a versatile new tool for MS-based proteomics. Particularly, the feasibility of the Ormocomp chips for rapid analysis of intact proteins with such a simple setup is a valuable increment to the current technology.

  15. An interface for online coupling capillary electrophoresis to dielectric barrier discharge ionization mass spectrometry.

    PubMed

    Zhang, Yiding; Ai, Wanpeng; Bai, Yu; Zhou, Yinglin; Wen, Luhong; Zhang, Xinxiang; Liu, Huwei

    2016-12-01

    The online combination of capillary electrophoresis (CE) with mass spectrometry (MS) has long been desired for the capability of direct and simultaneous separation and detection with high efficiency, accuracy, and throughput. In this work, a novel CE-MS interface was developed, using dielectric barrier discharge ionization (DBDI). The interface employed a spray tip with a coaxial three-layer structure, into which the CE sample solution, the sheath liquid, and the nebulizing gas were introduced. The spray tip was put between the DBDI outlet and the MS inlet, thus the CE sample solution could be blended with the sheath liquid, then nebulized. The nebulized sample could be ionized by DBDI, and finally analyzed by MS. The key parameters of the interface were optimized. Then, proof-of-concept experiments separating and detecting the mixture of metronidazole and acetaminophen solutions were conducted. The results showed high separation efficiency, low time consumption, high reproducibility, and convenience in operation. In addition, the interface exhibited a high tolerance of non-volatile salts and surfactants, which would be widely used in CE analyses. All of these results demonstrated that the newly developed CE-DBDI-MS interface could be successfully used in CE-MS studies, and could be further utilized in multiple areas involving efficient separation and detection.

  16. Capillary electrophoresis-mass spectrometry of basic proteins using a new physically adsorbed polymer coating. Some applications in food analysis.

    PubMed

    Simó, Carolina; Elvira, Carlos; González, Nieves; San Román, J; Barbas, Coral; Cifuentes, Alejandro

    2004-07-01

    A new physically adsorbed capillary coating for capillary electrophoresis-mass spectrometry (CE-MS) of basic proteins is presented, which is easily obtained by flushing the capillary with a polymer aqueous solution for two min. This coating significantly reduces the electrostatic adsorption of a group of basic proteins (i.e., cytochrome c, lysozyme, and ribonuclease A) onto the capillary wall allowing their analysis by CE-MS. The coating protocol is compatible with electrospray inonization (ESI)-MS via the reproducible separation of the standard basic proteins (%RSD values (n = 5) < 1% for analysis time reproducibility and < 5% for peak heights, measured from the total ion electropherograms (TIEs) within the same day). The LODs determined using cytochrome c with total ion current and extracted ion current defection were 24.5 and 2.9 fmol, respectively. Using this new coating lysozymes from chicken and turkey egg white could be easily distinguished by CE-MS, demonstrating the usefulness of this method to differentiate animal species. Even after sterilization at 120 degrees C for 30 min, lysozyme could be detected, as well as in wines at concentrations much lower than the limit marked by the EC Commission Regulation. Adulteration of minced meat with 5% of egg-white could also be analysed by our CE-MS protocol.

  17. Pressurized nano-liquid-junction interface for coupling capillary electrochromatography and nano-liquid chromatography with mass spectrometry.

    PubMed

    D'Orazio, Giovanni; Fanali, Salvatore

    2013-11-22

    A new nano-liquid-junction interface for coupling both capillary electrochromatography (CEC) or nano-liquid chromatography (nano-LC) with mass spectrometry (MS) was studied. The interface was a small T piece of polymeric material where capillary column and tip capillary were positioned at 180° while the third exit (at 90°) was occupied by a capillary delivering a liquid-assisting spray ionization for CEC experiments or by the electrode for the high voltage spray for nano-LC. Experiments were carried out analyzing mixtures of some organophosphorus pesticides (OPPs) or anti-inflammatory and related acidic drugs with MS detection in positive or negative ion mode, respectively. Analyzed OPPs compounds were baseline resolved utilizing the novel interface in both nano-LC and CEC obtaining good sensitivity and repeatability. For CEC-MS, the limits of detection ranged between 0.03 and 6.80 μg/mL and the intra-day repeatability was RSD <3.8% and <13% for the retention times and peak areas, respectively. The interface was easy to handle and good reproducibility, between 2.5 and 3.5% for the retention time and <10% for the efficiencies, was obtained when the interface was installed by two different analysts. Furthermore, it could be used for both CEC and nano-LC. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Capillary electrochromatography-atmospheric pressure ionization mass spectrometry of pesticides using a surfactant-bound monolithic column

    PubMed Central

    Gu, Congying; Shamsi, Shahab A.

    2011-01-01

    A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) (AAUA-EDMA) monolithic column was simply prepared by in-situ co-polymerization of AAUA and EDMA with 1-propanol, 1,4-butanediol and water as porogens in 100 µm id fused silica capillary in one step. This column was used in capillary electrochromatography (CEC)-atmospheric pressure photoionization (APPI)-mass spectrometry system for separation and detection of N-methylcarbamates (NMCs) pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design (FFD) was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature, and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design (CCD) was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions signal-to-noise ratios (S/N) around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine NMCs in spiked apple juice sample after solid phase extraction with recoveries in the range of 65 to 109%. PMID:20349511

  19. The use of a sulfonated capillary on chiral capillary electrophoresis/mass spectrometry of amphetamine-type stimulants for methamphetamine impurity profiling.

    PubMed

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

    2015-04-01

    Chiral capillary electrophoresis/tandem mass spectrometry (CE/MS/MS) using a chemically modified capillary containing sulfonated groups was developed for the following 8 amphetamine-type stimulants (ATS): amphetamine, methamphetamine (MA), norephedrine, norpseudoephedrine, ephedrine (EP), pseudoephedrine (pEP), dimethylamphetamine and methylephedrine. The running buffer was 10 mM formic acid containing 20 mM highly sulfated γ-cyclodextrin (pH 2.5) as the chiral selector. All 16 enantiomers were well resolved within 60 min, and precisely identified due to their characteristic mass spectra. Further, the RSDs of the migration times of the analytes were no more than 0.3% without any standardization. (1R,2S)-(-)-EP and (1S,2S)-(+)-pEP, which are important ATS impurities originating in the precursors, were added to a highly concentrated MA solution (1 mg/mL) and analyzed as mock samples for MA impurity analysis. Acceptable repeatability of the migration times of (-)-EP and (+)-pEP (ca. 0.3% RSDs) was still observed without interference from the large amount of MA. The limits of detection (LOD) of (-)-EP and (+)-pEP were approximately 2 μg/mL, therefore, their LOD as the impurity concentrations were calculated at about 0.2%. Seized MA samples were dissolved in water at a high concentration (1 mg/mL) and analyzed by this method. (-)-EP and (+)-pEP were clearly detected as impurities. Although these compounds had similar migration times and mass spectral patterns, the fine repeatability allowed easy identification of the impurities by a simple comparison of the absolute migration times of the specimens and those of authentic standards. This study is the first to report the use of a chemically modified capillary for the impurity profiling on CE/MS/MS. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Analysis of phytochelatin-cadmium complexes from plant tissue culture using nano-electrospray ionization tandem mass spectrometry and capillary liquid chromatography/electrospray ionization tandem mass spectrometry.

    PubMed

    Yen, T Y; Villa, J A; DeWitt, J G

    1999-09-01

    Phytochelatins (PCs, also known as class III metallothioneins), a family of sulfhydryl-rich peptides with the formula (gamma-GluCys)(n)Gly(Pc(n), n = 2-11), are induced in plants, yeast and fungi exposed to heavy metals, and are thought to detoxify metals by forming PC- metal complexes. Although PCs have been detected, PC- metal complexes have not been well characterized. In this work, nano-electrospray ionization tandem mass spectrometry (nano-ESI-MS/MS) and capillary liquid chromatography/electrospray ionization tandem mass spectrometry (capillary LC/ESI-MS/MS) methods were used to analyze PC - Cd complexes isolated from Datura innoxia, also known as Jimsonweed, cell culture exposed to Cd. With nano-ESI-MS/MS and capillary LC/ESI-MS/MS we could simultaneously detect the presence of PCs and PC - Cd complexes from plant cell extracts, unambiguously identify these species and elucidate the nature of individual PC - Cd complexes. Phytochelatins with n = 3-6 were detected, as were PC - Cd complexes with PC(3), PC(4) and PC(5). This is the first study to report the size and nature of native PC - Cd complexes from plant tissue samples. These results demonstrate that the direct analysis of plant extracts using nano-ESI-MS/MS and capillary LC/ESI-MS/MS methods is simple and sensitive to the range of PCs and PC - Cd complexes in plants. Hence these methods open up new opportunities for further quantitative analysis of PCs and PC - metal complexes in cell culture and plant systems to understand the relationship between the biosynthesis of these compounds and metal tolerance.

  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. 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...

  3. Robust and High-Throughput Method for Anionic Metabolite Profiling: Preventing Polyimide Aminolysis and Capillary Breakages under Alkaline Conditions in Capillary Electrophoresis-Mass Spectrometry.

    PubMed

    Yamamoto, Mai; Ly, Ritchie; Gill, Biban; Zhu, Yujie; Moran-Mirabal, Jose; Britz-McKibbin, Philip

    2016-11-01

    Capillary electrophoresis-mass spectrometry (CE-MS) represents a high efficiency microscale separation platform for untargeted profiling of polar/ionic metabolites that is ideal for volume-restricted biological specimens with minimal sample workup. Despite these advantages, the long-term stability of CE-MS remains a major obstacle hampering its widespread application in metabolomics notably for routine analysis of anionic metabolites under negative ion mode conditions. Herein, we report for the first time that commonly used ammonia containing buffers compatible with electrospray ionization (ESI)-MS can compromise the integrity of fused-silica capillaries via aminolysis of their outer polyimide coating. Unlike organic solvent swelling effects, this chemical process occurs under aqueous conditions that is dependent on ammonia concentration, buffer pH, and exposure time resulting in a higher incidence of capillary fractures and current errors during extended operation. Prevention of polyimide aminolysis is achieved by using weakly alkaline ammonia containing buffers (pH < 9) in order to preserve the tensile strength of the polyimide coated fused-silica capillary. Alternatively, less nucleophilic primary/secondary amines can be used as electrolytes without polyimide degradation, whereas chemically resistant polytetrafluoroethylene coating materials offer higher pH tolerance in ammonia. In this work, multisegment injection (MSI)-CE-MS was used as multiplexed separation platform for high throughput profiling of anionic metabolites when using optimized buffer conditions to prevent polyimide degradation. A diverse range of acidic metabolites in human urine were reliably measured by MSI-CE-MS via serial injection of seven urine samples within a single run, including organic acids, food-specific markers, microbial-derived compounds and over-the-counter drugs as their sulfate and glucuronide conjugates. This approach offers excellent throughput (<5 min/sample) and acceptable

  4. Microscale nonreductive release of O-linked glycans for subsequent analysis through MALDI mass spectrometry and capillary electrophoresis.

    PubMed

    Huang, Y; Mechref, Y; Novotny, M V

    2001-12-15

    A new beta-elimination-based procedure has been devised for a microscale release of O-linked oligosaccharides from glycoproteins. Unlike the conventional Carlson degradation, which leads to formation of alditols, the procedure reported here renders the reducing end intact. Conversion of the liberated oligosaccharides to glycosylamines in ammonia medium is followed by the production of the reducing oligosaccharides through the addition of boric acid. The quantitatively generated oligosaccharides with the reducing end can subsequently be derivatized with a fluorophoric reagent for capillary electrophoresis or, alternatively, analyzed through MALDI mass spectrometry. The microscale version of these chemical steps permits us to investigate structurally O-linked oligosaccharides at very low levels.

  5. Application of capillary gas chromatography mass spectrometry/computer techniques to synoptic survey of organic material in bed sediment

    USGS Publications Warehouse

    Steinheimer, T.R.; Pereira, W.E.; Johnson, S.M.

    1981-01-01

    A bed sediment sample taken from an area impacted by heavy industrial activity was analyzed for organic compounds of environmental significance. Extraction was effected on a Soxhlet apparatus using a freeze-dried sample. The Soxhlet extract was fractionated by silica gel micro-column adsorption chromatography. Separation and identification of the organic compounds was accomplished by capillary gas chromatography/mass spectrometry techniques. More than 50 compounds were identified; these include saturated hydrocarbons, olefins, aromatic hydrocarbons, alkylated polycyclic aromatic hydrocarbons, and oxygenated compounds such as aldehydes and ketones. The role of bed sediments as a source or sink for organic pollutants is discussed. ?? 1981.

  6. 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.

  7. Sulfated and sulfonated polysaccharide as chiral stationary phases for capillary electrochromatography and capillary electrochromatography–mass spectrometry

    PubMed Central

    Zheng, Jie; Bragg, William; Hou, Jingguo; Lin, Na; Chandrasekaran, Sekar; Shamsi, Shahab A.

    2009-01-01

    The applications of polysaccharide phenyl carbamate derivatives as chiral stationary phases (CSPs) for capillary electrochromatography (CEC) are often hindered by longer retention times, especially using a normal-phase (NP) eluent due to very low electroosmotic flow (EOF). Therefore, in this study, we propose an approach for the aforementioned problems by introducing two new types of negatively charged sulfate and sulfonated groups for polysaccharide CSPs. These CSPs were utilized to pack CEC columns for enantioseparation with a NP eluent. Compared to conventional cellulose tris(3,5-dimethylphenyl carbamate) or CDMPC CSPs, the sulfated CDMPC CSP (sulfur content 4.25%, w/w) shortened the analysis time up to 50% but with a significant loss of enantiomeric resolution (~60%). On the other hand, the sulfonated CDMPC CSP (sulfur content 1.76%, w/w) not only provided fast throughput but also maintained excellent resolving power. In addition, its synthesis is much more straightforward than the sulfated one. Furthermore, we studied several stationary phase parameters (CSP loading and silica gel pore size) and mobile phase parameters (including type of mobile phase and its composition) to evaluate the throughput and enantioselectivity. Using the optimized conditions, a chiral pool containing 66 analytes was screened to evaluate the enantioselectivity under three different mobile phase modes (i.e., NP, polar organic phase (POP) and reversed-phase (RP) eluents). Among these mobile phase modes, the RP mode showed the highest success rate, whereas some degree of complementary enantioselectivity was observed with NP and POP. Finally, the feasibility of applying this CSP for CEC–MS enantioseparation using internal tapered column was evaluated with NP, POP and RP eluents. In particular, the NP-CEC–MS provided significantly enhanced sensitivity when methanol was replaced with isopropanol in the sheath liquid. Using aminog-lutethimide as model chiral analyte, all three modes of

  8. Capillary electrophoresis–mass spectrometry as a powerful tool in biomarker discovery and clinical diagnosis: an update of recent developments

    PubMed Central

    Mischak, Harald; Coon, Joshua J.; Novak, Jan; Weissinger, Eva M.; Schanstra, Joost; Dominiczak, Anna F.

    2009-01-01

    Proteome analysis has emerged as a powerful technology to decipher biological processes. One of the main goals is to discover biomarkers for diseases from tissues and body fluids. However, the complexity and wide dynamic range of protein expression present an enormous challenge to separation technologies and mass spectrometry (MS). In this review, we examine the limitations of proteomics, and aim towards the definition of the current key prerequisites. We focus on capillary electrophoresis coupled to mass spectrometry (CE-MS), because this technique continues to show great promise. We discuss CE-MS from an application point of view, and evaluate its merits and vices for biomarker discovery and clinical applications. Finally, we present several examples on the use of CE-MS to determine urinary biomarkers and implications for disease diagnosis, prognosis, and therapy evaluation. PMID:18973238

  9. Amphetamine and derivatives in natural weight loss pills and dietary supplements by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Dos Santos, Vagner Bezerra; Daniel, Daniela; Singh, Melina; do Lago, Claudimir Lucio

    2016-12-01

    A capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) method for amphetamine (AM), phentermine (PTM), methamphetamine (MAM), methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), and methylenedioxyethylamphetamine (MDEA) in commercial samples of homeopathic and phytotherapic medicines and dietary supplements is presented. The samples were submitted to a modified QuEChERS extraction procedure (at apparent pH 13) followed by electrophoretic separation in 0.1molL(-1) formic acid electrolyte (pH 2.4) and detection by ESI-MS/MS. A polyvinyl alcohol coated capillary was employed to prevent the adsorption of the analytes to the capillary wall. The limits of detection and quantitation were from 0.02 to 0.06μgL(-1) and from 0.06 to 0.21μgL(-1), respectively, with recovery ranging from 85 to 123% and the standard deviations were not greater than 6.1%. In addition, the separation occurs in less than six minutes. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Bioanalysis for biocatalysis: multiplexed capillary electrophoresis-mass spectrometry assay for aminotransferase substrate discovery and specificity profiling.

    PubMed

    Mironov, Gleb G; St-Jacques, Antony D; Mungham, Alexander; Eason, Matthew G; Chica, Roberto A; Berezovski, Maxim V

    2013-09-18

    In this work, we introduce an entirely automated enzyme assay based on capillary electrophoresis coupled to electrospray ionization mass spectrometry termed MINISEP-MS for multiple interfluent nanoinjections-incubation-separation-enzyme profiling using mass spectrometry. MINISEP-MS requires only nanoliters of reagent solutions and uses the separation capillary as a microreactor, allowing multiple substrates to be assayed simultaneously. The method can be used to rapidly profile the substrate specificity of any enzyme and to measure steady-state kinetics in an automated fashion. We used the MINISEP-MS assay to profile the substrate specificity of three aminotransferases (E. coli aspartate aminotransferase, E. coli branched-chain amino acid aminotransferase, and Bacillus sp. YM-1 D-amino acid aminotransferase) for 33 potential amino acid substrates and to measure steady-state kinetics. Using MINISEP-MS, we were able to recapitulate the known substrate specificities and to discover new amino acid substrates for these industrially relevant enzymes. Additionally, we were able to measure the apparent K(M) and k(cat) parameters for amino acid donor substrates of these aminotransferases. Because of its many advantages, the MINISEP-MS assay has the potential of becoming a useful tool for researchers aiming to identify or create novel enzymes for specific biocatalytic applications.

  11. Metabolomics of adherent mammalian cells by capillary electrophoresis-mass spectrometry: HT-29 cells as case study.

    PubMed

    Ibáñez, Clara; Simó, Carolina; Valdés, Alberto; Campone, Luca; Piccinelli, Anna Lisa; García-Cañas, Virginia; Cifuentes, Alejandro

    2015-06-10

    In this work, the optimization of an effective protocol for cell metabolomics is described with special emphasis in the sample preparation and subsequent analysis of intracellular metabolites from adherent mammalian cells by capillary electrophoresis-mass spectrometry. As case study, colon cancer HT-29 cells, a human cell model to investigate colon cancer, are employed. The feasibility of the whole method for cell metabolomics is demonstrated via a fast and sensitive profiling of the intracellular metabolites HT-29 cells by capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF MS). The suitability of this methodology is further corroborated through the examination of the metabolic changes in the polyamines pathway produced in colon cancer HT-29 cells by difluoromethylornithine (DFMO), a known potent ornithine decarboxylase inhibitor. The selection of the optimum extraction conditions allowed a higher sample volume injection that led to an increase in CE-TOF MS sensitivity. Following a non-targeted metabolomics approach, 10 metabolites (namely, putrescine, ornithine, gamma-aminobutyric acid (GABA), oxidized and reduced glutathione, 5'-deoxy-5'-(methylthio)adenosine, N-acetylputrescine, cysteinyl-glycine, spermidine and an unknown compound) were found to be significantly altered by DFMO (p<0.05) in HT-29 cells. In addition to the effect of DFMO on polyamine metabolism, minor modifications of other metabolic pathways (e.g., related to intracellular thiol redox state) were observed.

  12. Recent advances in combination of capillary electrophoresis with mass spectrometry: methodology and theory.

    PubMed

    Klepárník, Karel

    2015-01-01

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

  13. Separation of actinides using capillary extraction chromatography-inductively coupled plasma mass spectrometry.

    PubMed

    Peterson, Dominic S; Montoya, Velma M

    2009-08-01

    Trace levels of actinides have been separated on capillary extraction chromatography columns. Detection of the actinides was achieved using an inductively coupled plasma mass spectrometer, which was coupled with the extraction chromatography system. In this study, we compare 30-cm long, 4.6 mm i.d. columns to capillary columns (750 microm i.d.) with lengths from 30 cm up to 150 cm. The columns that were tested were packed with TRU resin. We were able to separate a mixture of five actinides ((232)Th, (238)U, (237)Np, (239)Pu, and (241)Am). This work has application to rapid bioassay as well as automated separations of actinide materials.

  14. Structure analysis of lipoglycans and lipoglycan-derived carbohydrates by capillary electrophoresis and mass spectrometry.

    PubMed

    Lamari, Fotini N; Gioldassi, Xanthee M; Mitropoulou, Theoni N; Karamanos, Nikos K

    2002-04-01

    Lipoglycans (lipopolysaccharides, lipoarabinomannans and glycolipids) are unique components of the cell membrane of all cells and the envelope of many bacteria. They play important roles in determining cell-environment interactions, which, however, are only partly understood due to incomplete description of their structural components, lipids and glycans. Capillary electrophoresis is an analytical technique of high separation efficiency and minimum sample requirements and has successfully been used for the analysis of several molecules of biological importance: proteins, nucleic acids and glycoconjugates. In the last years, a few applications of capillary electrophoresis to the analysis of lipoglycans have been reported. Analysis of lipoglycans involves the study of two parameters: intact molecules and carbohydrate parts. The conjunction of capillary electrophoresis and mass spectroscopy not only enhances the detection sensitivity, but also provides structural information on these structurally complex molecules. The interest in the field is rising and the results from the exact determination on the lipoglycan structure are expected to improve our understanding of the molecular mechanism of lipoglycan binding to proteins and cells of host organisms as well as their relationship to the virulence and pathogenesis of bacteria. In this report, an overview of the capillary electrophoresis methods used to analyze and characterize the intact lipoglycans as well as their carbohydrate parts is presented. Copyright 2002 John Wiley & Sons, Ltd.

  15. 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...

  16. 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...

  17. Capillary isoelectric focusing of probiotic bacteria from cow's milk in tapered fused silica capillary with off-line matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification.

    PubMed

    Horká, Marie; Karásek, Pavel; Salplachta, Jiří; Růžička, Filip; Vykydalová, Marie; Kubesová, Anna; Dráb, Vladimír; Roth, Michal; Slais, Karel

    2013-07-25

    In this study, combination of capillary isoelectric focusing (CIEF) in tapered fused silica (FS) capillary with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is presented as an efficient approach for unambiguous identification of probiotic bacteria in real sample. For this purpose, bacteria within genus Lactobacillus were selected as model bioanalytes and cow's milk was selected as a biological sample. CIEF analysis of both the cultivated bacteria and the bacteria in the milk was optimized and isoelectric points characterizing the examined bacteria were subsequently determined independently of the bacterial sample origin. The use of tapered FS capillary significantly enhanced the separation capacity and efficiency of the CIEF analyses performed. In addition, the cell number injected into the tapered FS capillary was quantified and an excellent linearity of the calibration curves was achieved which enabled quantitative analysis of the bacteria by CIEF with UV detection. The minimum detectable number of bacterial cells was 2×10(6) mL(-1). Finally, cow's milk spiked with the selected bacterium was analyzed by CIEF in tapered FS capillary, the focused and detected bacterial cells were collected from the capillary, deposited onto the cultivation medium, and identified using MALDI-TOF MS afterward. Our results have revealed that the proposed procedure can be advantageously used for unambiguous identification of probiotic bacteria in a real sample.

  18. Quantitative analysis of [Dmt(1)]DALDA in ovine plasma by capillary liquid chromatography-nanospray ion-trap mass spectrometry.

    PubMed

    Wan, Haibao; Umstot, Edward S; Szeto, Hazel H; Schiller, Peter W; Desiderio, Dominic M

    2004-04-15

    The synthetic opioid peptide analog Dmt-D-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA; [Dmt= 2',6'-dimethyltyrosine) is a highly potent and selective mu opioid-receptor agonist. A very sensitive and robust capillary liquid chromatography/nanospray ion-trap (IT) mass spectrometry method has been developed to quantify [Dmt(1)]DALDA in ovine plasma, using deuterated [Dmt(1)]DALDA as the internal standard. The standard MS/MS spectra of d(0)- and d(5)-[Dmt(1)]DALDA were obtained, and the collision energy was experimentally optimized to 25%. The product ion [ M + 2H-NH(3)](2+) (m/z 312.2) was used to identify and to quantify the synthetic opioid peptide analog in ovine plasma samples. The MS/MS detection sensitivity for [Dmt(1)]DALDA was 625 amol. A calibration curve was constructed, and quantitative analysis was performed on a series of ovine plasma samples.

  19. Pyrolysis-capillary gas chromatography-mass spectrometry for the determination of polyvinyl chloride traces in solid environmental samples.

    PubMed

    Tienpont, B; David, F; Vanwalleghem, F; Sandra, P

    2001-03-16

    A novel method based on pyrolysis-capillary gas chromatography-mass spectrometry (CGC-MS) was developed for the quantitative analysis of polyvinylchloride (PVC) in solid environmental samples like sludge and dust. The samples are extracted and the extract is fractionated by solid-phase extraction (SPE). Possibly interfering biological and frequently occuring synthetic polymers are removed by this clean-up. The final extract is analyzed by pyrolysis-CGC-MS. Selective detection of PVC is performed by using specific markers in the pyrogram. Quantitation is done on naphthalene. Good linearity was obtained in a range from 0.5 to 100 microg applied to the pyrolyser. The limit of quantitation (LOQ) in sludge and dust samples is 10 mg/kg dry mass. A correlation between PVC and phthalates was made for sewage sludge samples.

  20. Feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization mass spectrometry in analyzing anabolic steroids in urine samples.

    PubMed

    Ahonen, Linda L; Haapala, Markus; Saarela, Ville; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2010-04-15

    We examined the feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization tandem mass spectrometry (capLC/microAPPI-MS/MS) for the analysis of anabolic steroids in human urine. The urine samples were pretreated by enzymatic hydrolysis (with beta-glucuronidase from Helix pomatia), and the compounds were liquid-liquid extracted with diethyl ether. After separation the compounds were vaporized by microchip APPI, photoionized by a 10 eV krypton discharge lamp, and detected by selected reaction monitoring. The capLC/microAPPI-MS/MS method showed good sensitivity with detection limits at the level of 1.0 ng mL(-1), good linearity with correlation coefficients between 0.9954 and 0.9990, and good repeatability with relative standard deviations below 10%. These results demonstrate that microchip APPI combined with capLC/MS/MS provides a new potential method for analyzing non-polar and neutral compounds in biological samples.

  1. Direct gas-phase detection of nerve and blister warfare agents utilizing active capillary plasma ionization mass spectrometry.

    PubMed

    Wolf, J-C; Schaer, M; P Siegenthaler, P; Zenobi, R

    2015-01-01

    Ultrasensitive direct gas-phase detection of chemical warfare agents (CWAs) is demonstrated utilizing active capillary plasma ionization and triple quadrupole mass spectrometry (MS) instrumentation. Four G- agents, two V-agents and various blistering agents [including sulfur mustard (HD)] were detected directly in the gas phase with limits of detection in the low parts per trillion (ng m(-3)) range. The direct detection of HD was shown for dry carrier gas conditions, but signals vanished when humidity was present, indicating a possible direct detection of HD after sufficient gas phase pretreatment. The method provided sufficient sensitivity to monitor directly the investigated volatile CWAs way below their corresponding minimal effect dose, and in most cases even below the eight hours worker exposure concentration. In general, the ionization is very soft, with little to no in-source fragmentation. Especially for the G-agents, some dimer formation occurred at higher concentrations. This adds complexity, but also further selectivity, to the corresponding mass spectra. Our results show that the active capillary plasma ionization is a robust, sensitive, "plug and play" ambient ionization source suited (but not exclusively) to the very sensitive detection of CWAs. It has the potential to be used with portable MS instrumentation.

  2. A capillary electrophoresis coupled to mass spectrometry pipeline for long term comparable assessment of the urinary metabolome

    PubMed Central

    Boizard, Franck; Brunchault, Valérie; Moulos, Panagiotis; Breuil, Benjamin; Klein, Julie; Lounis, Nadia; Caubet, Cécile; Tellier, Stéphanie; Bascands, Jean-Loup; Decramer, Stéphane; Schanstra, Joost P.; Buffin-Meyer, Bénédicte

    2016-01-01

    Although capillary electrophoresis coupled to mass spectrometry (CE-MS) has potential application in the field of metabolite profiling, very few studies actually used CE-MS to identify clinically useful body fluid metabolites. Here we present an optimized CE-MS setup and analysis pipeline to reproducibly explore the metabolite content of urine. We show that the use of a beveled tip capillary improves the sensitivity of detection over a flat tip. We also present a novel normalization procedure based on the use of endogenous stable urinary metabolites identified in the combined metabolome of 75 different urine samples from healthy and diseased individuals. This method allows a highly reproducible comparison of the same sample analyzed nearly 130 times over a range of 4 years. To demonstrate the use of this pipeline in clinical research we compared the urinary metabolome of 34 newborns with ureteropelvic junction (UPJ) obstruction and 15 healthy newborns. We identified 32 features with differential urinary abundance. Combination of the 32 compounds in a SVM classifier predicted with 76% sensitivity and 86% specificity UPJ obstruction in a separate validation cohort of 24 individuals. Thus, this study demonstrates the feasibility to use CE-MS as a tool for the identification of clinically relevant urinary metabolites. PMID:27694997

  3. 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.

  4. Metabolic Profiling with Gas Chromatography-Mass Spectrometry and Capillary Electrophoresis-Mass Spectrometry Reveals the Carbon-Nitrogen Status of Tobacco Leaves Across Different Planting Areas.

    PubMed

    Zhao, Jieyu; Zhao, Yanni; Hu, Chunxiu; Zhao, Chunxia; Zhang, Junjie; Li, Lili; Zeng, Jun; Peng, Xiaojun; Lu, Xin; Xu, Guowang

    2016-02-05

    The interaction between carbon (C) and nitrogen (N) metabolism can reflect plant growth status and environmental factors. Little is known regarding the connections between C-N metabolism and growing regions under field conditions. To comprehensively investigate the relationship in mature tobacco leaves, we established metabolomics approaches based on gas chromatography-mass spectrometry (GC-MS) and capillary electrophoresis-time-of-flight-mass spectrometry (CE-TOF-MS). Approximately 240 polar metabolites were determined. Multivariate statistical analysis revealed that the growing region greatly influenced the metabolic profiles of tobacco leaves. A metabolic correlation network and related pathway maps were used to reveal the global overview of the alteration of C-N metabolism across three typical regions. In Yunnan, sugars and tricarboxylic acid (TCA) cycle intermediates were closely correlated with amino acid pools. Henan tobacco leaves showed positive correlation between the pentose phosphate pathway (PPP) intermediates and C-rich secondary metabolism. In Guizhou, the proline and asparagine had significant links with TCA cycle intermediates and urea cycle, and antioxidant accumulation was observed in response to drought. These results demonstrate that combined analytical approaches have great potential to detect polar metabolites and provide information on C-N metabolism related to planting regional characteristics.

  5. Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometry based on the use of non-volatile buffers.

    PubMed

    Gottardo, Rossella; Mikšík, Ivan; Aturki, Zeineb; Sorio, Daniela; Seri, Catia; Fanali, Salvatore; Tagliaro, Franco

    2012-02-01

    The present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization-time of flight mass spectrometry (CZE-ESI-TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6-monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non-volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis-mass spectrometry (CE-MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided.

  6. Determination of halosulfuron-methyl herbicide in sugarcane juice and tomato by capillary electrophoresis-tandem mass spectrometry.

    PubMed

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

    2015-05-15

    A capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) method for the determination of halosulfuron-methyl (HSU) residue in samples of sugarcane juice and tomato is introduced and validated. The samples were submitted to a QuEChERS extraction procedure followed by electrophoretic separation in NH4HCO3 electrolyte (adjusted to pH 8.5) and detection by electrospray-tandem mass spectrometry. The total HSU migration took place in less than 3.5 min, and the detection was accomplished by monitoring three fragmentation processes of this anion: m/z 435-182, 139, and 83. The R(2) values for concentrations up to 100 ppb (μg kg(-1)) were, respectively, 0.992, 0.992, and 0.978. Recovery values for samples spiked at three concentration levels (10, 20 and 50 ppb) were in the range of 96-104% with standard deviation not greater than 5.0%. The limit of detection for HSU in sugarcane juice and tomato was 2 ppb for both samples.

  7. Simultaneous separation and confirmation of amphetamine and related drugs in equine plasma by non-aqueous capillary-electrophoresis-tandem mass spectrometry.

    PubMed

    Li, X Q; Uboh, C E; Soma, L R; Guan, F Y; You, Y W; Kahler, M C; Judy, J A; Liu, Y; Chen, J W

    2010-02-01

    A non-aqueous capillary electrophoresis-mass spectrometry (NACE-MS) method was developed for simultaneous separation and identification of 12 amphetamine and related compounds in equine plasma. Analytes were recovered from plasma by liquid-liquid extraction using methyl tertiary butyl ether (MTBE). A bare fused-silica capillary was used for separation of the analytes. Addition of sheath liquid to the capillary effluent allowed the detection of the analytes by positive electrospray ionization mass spectrometry using full scan data acquisition. The limit of detection (LOD) for the target analytes was 10-200 ng/mL and that of confirmation (LOC) was 50-1000 ng/mL in equine plasma. Capillary electrophoresis (CE) and mass spectrometry (MS) parameters were optimized for full CE separation and MS detection of the analytes. Separation buffer comprised 25 mM ammonium formate in acetonitrile/methanol (20: 80, v/v) plus 1 M formic acid. Sheath liquid was isopropanol-water-formic acid (50:50:0.5, v/v/v). Samples were hydrodynamically injected and separated at 25 kV. Analytes were electrokinetically separated and mass spectrometrically identified and confirmed. This simple, fast, inexpensive and reproducible method was successfully applied to post race equine plasma and research samples in screening for amphetamine and related drugs.

  8. 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

  9. Analysis of calcitonin and its analogues by capillary zone electrophoresis and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry.

    PubMed

    Amini, Ahmad; Olofsson, Ing-Marie

    2004-06-01

    Capillary zone electrophoretic (CZE) separations and mass spectrometric analysis of salmon calcitonin and related analogues were performed to generate electrophoresis and mass fingerprints for quality control of the recombinant polypeptide pharmaceutical salmon calcitonin. The calcitonins and their corresponding tryptic digests were successfully separated by CZE at low pH in fused silica capillaries dynamically modified with poly-cationic polymers. The poly-cationic modified inner surface of the fused silica capillaries generated a strong anionic electroosmotic flow (EOF). Analytes of negative, neutral, and positive charge were all swept through the capillary toward the positive electrode. Compared to Polybrene-coated capillaries, capillaries coated with PEI showed a markedly slower but much more stable electroosmotic flow. The migration order of the analytes was predicted by comparing approximate values of the charge to (molecular mass)2/3 ratios. The predicted migration order was confirmed by off-line analysis of CZE fractions with matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

  10. [A simple preparation method of an electric heating apparatus for heating capillary chromatographic columns and its application in liquid chromatography-mass spectrometry system].

    PubMed

    Jin, Zuyao; Lü, Yayao; Zhou, Shanshan; Hao, Feiran; Fu, Bin; Ying, Wantao; Qian, Xiaohong; Zhang, Yangjun

    2015-06-01

    For deep coverage of proteome, especially in performing qualitative identification and quantitative analysis of low-abundance proteins, the most commonly used method is the application of a longer capillary chromatographic column or a capillary column packed with smaller particle sizes. However, this causes another problem, the very high back pressure which results in liquid leaks in some connection parts in a liquid chromatograph. To solve this problem, an electric heating apparatus was developed to raise the temperature of a capillary column for reducing its back pressure, which was further applied in a capillary high performance liquid chromatography-tandem mass spectrometry system (cHPLC-MS/MS), and evaluated in the terms of chromatographic column back pressure and chromatographic column efficiency using bovine serum albumin (BSA) tryptic digests and yeast tryptic digests, separately. The results showed that at the optimum current, our electric heating apparatus could reduce the column pressure of a capillary column packed with 3 µm packing materials by at least 50% during the separation of BSA tryptic digestion and yeast tryptic digestion, compared with that without electric heating. The column efficiency was also increased slightly. This suggested that the electric heating apparatus can significantly reduce the column pressure, which provides an efficient way to use capillary chromatographic columns packed with smaller sizes of particles at a lower pressure.

  11. Quantification of Fumaria officinalis isoquinoline alkaloids by nonaqueous capillary electrophoresis-electrospray ion trap mass spectrometry.

    PubMed

    Sturm, Sonja; Strasser, Eva-Maria; Stuppner, Hermann

    2006-04-21

    A capillary electrophoresis (CE) method using non-aqueous (NA) separation solutions combined with an ion trap mass spectrometer (MS and MS/MS) as detection device is presented for the separation, identification and quantification of isoquinoline alkaloids from Fumaria officinalis. The best results were obtained with a mixture of acetonitrile-methanol (9:1, v/v) containing 60mM ammonium acetate and 2.2M acetic acid as running electrolyte and an applied voltage of 30 kV. Electrospray MS measurements were performed in the positive ionization mode with isopropanol-water (1:1, v/v) as sheath liquid at a flow rate of 3 microl/min. Alkaloids were detected as [M+H](+)-ions and showed typical fragmentation patterns in MS/MS experiments. The developed assay was used for the quantification of seven isoquinoline alkaloids representing different structural subtypes in Fumariae herba extracts and F. herba containing phytopharmaceuticals.

  12. Separation of actinides using capillary extraction chromatography-inductively coupled plasma mass spectrometry

    SciTech Connect

    Peterson, Dominic S

    2008-01-01

    Trace levels of actinides have been separated on extraction chromatography columns. Detection of the actinides was achieved using an inductively coupled plasma mass spectrometer (ICP-MS), which was coupled with the extraction chromatography system. In this study we compare 30 cm long, 4.6 mm ID columns to capillary columns (750 {micro}m ID) with lengths from 30 cm up to 150 cm. The columns that were tested were packed with TRU resin. We were able to separate a mixture of five actinides ({sup 232}Th, {sup 238}U, {sup 237}Np, {sup 239}pU, {sup 241}Am). This work has application to rapid bioassay as well as for automated separations of actinide materials.

  13. Simultaneous oxytocin and arg-vasopressin measurements in microdialysates using capillary liquid chromatography-mass spectrometry

    PubMed Central

    Mabrouk, Omar S.; Kennedy, Robert T.

    2012-01-01

    Oxytocin (OXT) and arg-vasopressin (AVP) are nonapeptides with many important functions both peripherally and centrally. Intracerebral microdialysis has helped characterize their importance in regulating complex social and emotional processes. Radioiummunoassay is the most commonly used analytical method used for OXT and AVP measurements in microdialysates. These measurements have several well-known issues including single peptide per assay limit, possible cross-reactivity between structurally related peptides, and laborious sample preparation with radioactive materials. Here we demonstrate the use of capillary LC-MS3 for measuring OXT and AVP simultaneously in dialysates at a 10 min sampling frequency. Microdialysate samples required no preparation and instrumentation was commercially available. Microdialysis probes made with polyacrylonitrile membranes were suitable for high level recovery of the peptides in vitro and in vivo. Responses were linear from 1 – 100 pM. Matrix effect was assessed by standard addition experiments and by comparing signal intensities of OXT and AVP standards made in aCSF or dialysate. It was determined that the online washing step used on this setup was adequate for removing contaminants which interfere with electrospray ionization efficiency. In vivo, both peptides were stimulated by high K+ (75 mM) aCSF perfusion in the paraventricular nucleus (PVN). Also, a systemic injection of high Na+ (2M) caused a rapid and transient increase in PVN OXT while AVP increased only after 1.5 h. Our findings suggest that Capillary LC-MS3 is a straightforward method for monitoring OXT and AVP simultaneously from complex samples such as dialysates. PMID:22710285

  14. Comparing and combining capillary electrophoresis electrospray ionization mass spectrometry and nano-liquid chromatography electrospray ionization mass spectrometry for the characterization of post-translationally modified histones.

    PubMed

    Sarg, Bettina; Faserl, Klaus; Kremser, Leopold; Halfinger, Bernhard; Sebastiano, Roberto; Lindner, Herbert H

    2013-09-01

    We present the first comprehensive capillary electrophoresis electrospray ionization mass spectrometry (CESI-MS) analysis of post-translational modifications derived from H1 and core histones. Using a capillary electrophoresis system equipped with a sheathless high-sensitivity porous sprayer and nano-liquid chromatography electrospray ionization mass spectrometry (nano-LC-ESI-MS) as two complementary techniques, we characterized H1 histones isolated from rat testis. Without any pre-separation of the perchloric acid extraction, a total of 70 different modified peptides, including 50 phosphopeptides, were identified in the rat linker histones H1.0, H1a-H1e, and H1t. Out of the 70 modified H1 histone peptides, 27 peptides could be identified with CESI-MS only, and 11 solely with LC-ESI-MS. Immobilized metal-affinity chromatography enrichment prior to MS analysis yielded a total of 55 phosphopeptides; 22 of these peptides could be identified only by CESI-MS, and 19 only by LC-ESI-MS, showing the complementarity of the two techniques. We mapped 42 H1 modification sites, including 31 phosphorylation sites, of which 8 were novel sites. For the analysis of core histones, we chose a different strategy. In a first step, the sulfuric-acid-extracted core histones were pre-separated using reverse-phase high-performance liquid chromatography. Individual rat testis core histone fractions obtained in this way were digested and analyzed via bottom-up CESI-MS. This approach yielded the identification of 42 different modification sites including acetylation (lysine and N(α)-terminal); mono-, di-, and trimethylation; and phosphorylation. When we applied CESI-MS for the analysis of intact core histone subtypes from butyrate-treated mouse tumor cells, we were able to rapidly detect their degree of modification, and we found this method very useful for the separation of isobaric trimethyl and acetyl modifications. Taken together, our results highlight the need for additional techniques

  15. Comparing and Combining Capillary Electrophoresis Electrospray Ionization Mass Spectrometry and Nano–Liquid Chromatography Electrospray Ionization Mass Spectrometry for the Characterization of Post-translationally Modified Histones

    PubMed Central

    Sarg, Bettina; Faserl, Klaus; Kremser, Leopold; Halfinger, Bernhard; Sebastiano, Roberto; Lindner, Herbert H.

    2013-01-01

    We present the first comprehensive capillary electrophoresis electrospray ionization mass spectrometry (CESI-MS) analysis of post-translational modifications derived from H1 and core histones. Using a capillary electrophoresis system equipped with a sheathless high-sensitivity porous sprayer and nano–liquid chromatography electrospray ionization mass spectrometry (nano-LC-ESI-MS) as two complementary techniques, we characterized H1 histones isolated from rat testis. Without any pre-separation of the perchloric acid extraction, a total of 70 different modified peptides, including 50 phosphopeptides, were identified in the rat linker histones H1.0, H1a-H1e, and H1t. Out of the 70 modified H1 histone peptides, 27 peptides could be identified with CESI-MS only, and 11 solely with LC-ESI-MS. Immobilized metal-affinity chromatography enrichment prior to MS analysis yielded a total of 55 phosphopeptides; 22 of these peptides could be identified only by CESI-MS, and 19 only by LC-ESI-MS, showing the complementarity of the two techniques. We mapped 42 H1 modification sites, including 31 phosphorylation sites, of which 8 were novel sites. For the analysis of core histones, we chose a different strategy. In a first step, the sulfuric-acid-extracted core histones were pre-separated using reverse-phase high-performance liquid chromatography. Individual rat testis core histone fractions obtained in this way were digested and analyzed via bottom-up CESI-MS. This approach yielded the identification of 42 different modification sites including acetylation (lysine and Nα-terminal); mono-, di-, and trimethylation; and phosphorylation. When we applied CESI-MS for the analysis of intact core histone subtypes from butyrate-treated mouse tumor cells, we were able to rapidly detect their degree of modification, and we found this method very useful for the separation of isobaric trimethyl and acetyl modifications. Taken together, our results highlight the need for additional techniques

  16. Capillary electrophoresis/mass spectrometry determination of inorganic ions using an ion spray-sheath flow interface.

    PubMed

    Huggins, T G; Henion, J D

    1993-01-01

    The determination of inorganic cations and anions by capillary electrophoresis/mass spectrometry (CE/MS) is reported using an ion spray-sheath flow interface coupling. A twelve-component synthetic mixture of cations which included the positive ions of K, Ba, Ca, Mn, Cd, Co, Pb, Cr, Ni, Zn, Ag, and Cu was loaded into the capillary column at levels ranging from 30 to 300 pg, separated by CE, and detected by indirect UV and in the full-scan (m/z 35-450) positive ion CE/MS mode using an aqueous buffer containing 30 mM creatinine and 8 mM alpha-hydroxyisobutyric acid, pH 4.8. Creatinine forms adducts with the cations which are observed in the gas phase and requires rather high (120 electron volts) declustering energy to dissociate. This produces a reduction in charge state to form the free, singly charged, inorganic cations which are observed in the mass spectra. CE/MS analysis of an aqueous acidic extract of used aircraft engine oil revealed high levels of lead as well as lower levels of chromium and nickel. CE-indirect UV analysis of a synthetic mixture containing 300 pg each of 11 inorganic ions, which included the anions of Br, Cl, NO2, NO3, S2O3, N3, SCN, SO4, SeO4, oxalate, and MoO4, is shown. The running buffer which affected this separation contained 5 mM ammonium dichromate, 10 mM ammonium acetate, and 20 mM diethylenetriamine at pH 9.3. Although indirect UV detection revealed good separation of these anions, CE/MS analysis of this mixture was complicated by interfering ion current signals from the cluster ions formed by the interaction between the additives and the analytes.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Determination of serotonin and its precursors in chocolate samples by capillary liquid chromatography with mass spectrometry detection.

    PubMed

    Guillén-Casla, V; Rosales-Conrado, N; León-González, M E; Pérez-Arribas, L V; Polo-Díez, L M

    2012-04-06

    A method for the analysis of serotonin (5-HT) and its precursors, 5-hydroxytryptophan (5-HTP) and l-tryptophan (TP) in chocolate samples by capillary liquid chromatography-mass spectrometry (cLC-MS) has been developed. Optimum chromatographic conditions were established by using a personalized multifactorial experimental design. Finally the cLC separation was achieved through a mixture of acetonitrile and 5mM ammonium formate at pH 4 (3:97, v/v) as mobile phase in gradient elution, setting the injection volume at 10 μL and using pure water as injection solvent for focusing purposes on the head of the capillary column. For extraction of targets in chocolate samples a new, fast and simple procedure based on the use of acidic extraction medium and sonication was developed. Working in selected ion mode (m/z 177 for 5-HT, m/z 205 for l-tryptophan and m/z 221 for 5-HTP) detection limits were between 0.01 and 0.11 μg g(-1) and linearity was in the concentration range of 0.5-25 μg g(-1). Recoveries higher than 76% with RSDs lower than 8% were obtained from spiked samples for all analytes, showing the effectiveness of the proposed method. Serotonin and its precursors were determined in 5 kinds of commonly consumed chocolates with different cocoa contents (70-100%). The highest serotonin content was found in chocolate with a cocoa content of 85% (2.93 μg g(-1)). Regarding l-tryptophan, the highest content of this amino acid (13.27-13.34 μg g(-1)) was found in chocolate samples with the lowest cocoa content (70-85%). 5-Hydroxytryptophan was not detected in any chocolate samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Speciation of mercury by hydrostatically modified electroosmotic flow capillary electrophoresis coupled with volatile species generation atomic fluorescence spectrometry.

    PubMed

    Yan, Xiu-Ping; Yin, Xue-Bo; Jiang, Dong-Qing; He, Xi-Wen

    2003-04-01

    A novel method for speciation analysis of mercury was developed by on-line hyphenating capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS). The four mercury species of inorganic mercury Hg(II), methymercury MeHg(I), ethylmercury EtHg(I), and phenylmercury PhHg(I) were separated as mercury-cysteine complexes by CE in a 50-cm x 100-microm-i.d. fused-silica capillary at 15 kV and using a mixture of 100 mmol L(-1) of boric acid and 12% v/v methanol (pH 9.1) as electrolyte. A novel technique, hydrostatically modified electroosmotic flow (HSMEOF) in which the electroosmotic flow (EOF) was modified by applying hydrostatical pressure opposite to the direction of EOF was used to improve resolution. A volatile species generation technique was used to convert the mercury species into their respective volatile species. A newly developed CE-AFS interface was employed to provide an electrical connection for stable electrophoretic separations and to allow on-line volatile species formation. The generated volatile species were on-line detected with AFS. The precisions (RSD, n = 5) were in the range of 1.9-2.5% for migration time, 1.8-6.3% for peak area response, and 2.3-6.1% for peak height response for the four mercury species. The detection limits ranged from 6.8 to 16.5 microg L(-1) (as Hg). The recoveries of the four mercury species in the water samples were in the range of 86.6-111%. The developed technique was successfully applied to speciation analysis of mercury in a certified reference material (DORM-2, dogfish muscle).

  19. Highly sensitive capillary electrophoresis-mass spectrometry for rapid screening and accurate quantitation of drugs of abuse in urine.

    PubMed

    Kohler, Isabelle; Schappler, Julie; Rudaz, Serge

    2013-05-30

    The combination of capillary electrophoresis (CE) and mass spectrometry (MS) is particularly well adapted to bioanalysis due to its high separation efficiency, selectivity, and sensitivity; its short analytical time; and its low solvent and sample consumption. For clinical and forensic toxicology, a two-step analysis is usually performed: first, a screening step for compound identification, and second, confirmation and/or accurate quantitation in cases of presumed positive results. In this study, a fast and sensitive CE-MS workflow was developed for the screening and quantitation of drugs of abuse in urine samples. A CE with a time-of-flight MS (CE-TOF/MS) screening method was developed using a simple urine dilution and on-line sample preconcentration with pH-mediated stacking. The sample stacking allowed for a high loading capacity (20.5% of the capillary length), leading to limits of detection as low as 2 ng mL(-1) for drugs of abuse. Compound quantitation of positive samples was performed by CE-MS/MS with a triple quadrupole MS equipped with an adapted triple-tube sprayer and an electrospray ionization (ESI) source. The CE-ESI-MS/MS method was validated for two model compounds, cocaine (COC) and methadone (MTD), according to the Guidance of the Food and Drug Administration. The quantitative performance was evaluated for selectivity, response function, the lower limit of quantitation, trueness, precision, and accuracy. COC and MTD detection in urine samples was determined to be accurate over the range of 10-1000 ng mL(-1) and 21-1000 ng mL(-1), respectively.

  20. Searching for urine biomarkers of bladder cancer recurrence using a liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry metabolomics approach.

    PubMed

    Alberice, Juliana Vieira; Amaral, Andre F S; Armitage, Emily Grace; Lorente, José Antonio; Algaba, Ferrán; Carrilho, Emanuel; Márquez, Mirari; García, Antonia; Malats, Núria; Barbas, Coral

    2013-11-29

    The incidence and rate of recurrence of bladder cancer is high, particularly in developed countries, however current methods for diagnosis are limited to detecting high-grade tumours using often invasive methods. A panel of biomarkers to characterise tumours of different grades that could also distinguish between patients exhibiting the disease with first incidence or recurrence could be useful for bladder cancer diagnostics. In this study, potential metabolic biomarkers have been discovered through mass spectrometry based metabolomics of urine. Pre-treatment urine samples were collected from 48 patients diagnosed of urothelial bladder cancer. Patients were followed-up through the hospital pathological charts to identify whether and when the disease recurred or progressed. Subsequently, they were classified according to whether or not they suffered a tumour recurrence (recurrent or stable) as well as their risk group according to tumour grade and stage. Identified metabolites have been analysed in terms of disease characteristics (tumour stage and recurrence) and have provided an insight into bladder cancer progression. Using both liquid chromatography and capillary electrophoresis-mass spectrometry, a total of 27 metabolite features were highlighted as significantly different between patient groups. Some, for example histidine, phenylalanine, tyrosine and tryptophan have been previously linked with bladder cancer, however until now their connection with bladder cancer progression has not been previously reported. The candidate biomarkers revealed in this study could be useful in the clinic for diagnosis of bladder cancer and, through characterising the stage of the disease, could also be useful in prognostics. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Selective screening of glutaric acid acidurias by capillary electrophoresis-mass spectrometry.

    PubMed

    Fernández-Bravo, Jaime; de Andrés, Fernando; Zougagh, Mohammed; Ríos, Ángel

    2017-10-25

    A sensitive and selective method for the separation and quantification of the three organic acids 3-hydroxy-3-methylglutaric acid, 3-methylglutaric acid, and glutaric acid in human urine samples by CE with mass spectrometry detection has been developed. This methodology is faster, simpler and less time-consuming, than other methodologies previously described, and requires of reduced amounts of reagents as well. Samples are first filtered and then diluted in water. For the electrophoretic separation, a 20mM ammonium acetate and 10% methanol solution at pH 9.1 was selected as the running electrolyte. With 5-s hydrodynamic injection, detection limits ranging from 15.5 to 39.3μM and linear responses ranging from the LOQ calculated for each analyte to more than 400μM were obtained for the analysis of the different organic acids in less than 13min. Remarkable selectivity is achieved by mass spectrometry detection using 0.25% of formic acid in 50% v/v 2-propanol-water solution as sheath liquid, and enough sensitivity without interferences from the matrices was obtained as well. This methodology has revealed as an efficient approach to help the 3-hydroxy-3-methylglutaric aciduria diagnoses in order to discard or confirm the occurrence of the disease as of the presence or absence of the expected increased levels of these analytes in samples of potential patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Analysis of benzalkonium chloride by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Para, Bianca Veronica; Núñez, Oscar; Moyano, Encarnación; Galceran, Maria Teresa

    2006-06-01

    Conditions for the separation and determination of benzalkonium chloride (BAC) homologues by CE with UV-detection and CE coupled to MS (IT) using electrospray as ionization source were established. The separation was performed using fused-silica capillaries of 50 microm id and 100 mM acetic acid-ammonium acetate buffer solution at pH 4.5 with 80% of ACN as carrier electrolyte. CE-MS coupling parameters were optimized and methanol-10 mM acetic acid (90:10 v/v) was selected as sheath liquid. Detection limits, based on an S/N of 3:1, were calculated, and values between 0.8 and 1.3 mg/L with CE-ESI/MS and around 0.5 mg/L with CE-ESI-MS/MS, using hydrodynamic injection (15 s, 3.5 kPa), were obtained. Good run-to-run and day-to-day precisions on concentration were achieved with RSDs lower than 8%. Quantitative analysis was carried out by the internal standard method and the calibration curves showed good linearities (r(2) > 0.98). The CE-ESI-MS/MS method was successfully applied to the analysis of BAC in different ophthalmic solutions, allowing the direct determination, identification and confirmation of the BAC homologues presented in these samples.

  3. Monitoring potential prostate cancer biomarkers in urine by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Soliman, Laiel C; Hui, Yu; Hewavitharana, Amitha K; Chen, David D Y

    2012-12-07

    Current prostate cancer (PCa) diagnosis based on prostate-specific antigen (PSA) has been gradually losing its credibility over the last decade due to contradictory results in published literature and clinical practice. Recently, a group of potential PCa biomarkers in urine, particularly sarcosine, was found to increase significantly as the cancer progressed to metastasis. We report a simple, robust, and reproducible CE-ESI-MS/MS method for the determination of sarcosine and other representative potential biomarkers in pooled urine. The pooled urine was obtained from 20 healthy adult volunteers between the ages of 23-30 years old. A solid phase extraction (SPE) technique was optimized for maximum recovery of sarcosine. With no derivatization step, excellent resolution between sarcosine and its isomers (α-alanine and β-alanine) was achieved. A separate non-SPE method was also developed for quantitative determination of highly concentrated urinary metabolites. CE separation was performed on a positively-charged, polyethyleneimine (PEI)-coated capillary using 0.4-2% formic acid in 50% methanol. Precision for intra- and inter-day standard addition calibration of sarcosine were found to be within 15%, whereas intra-day precisions for the rest of the metabolites varied from 0.03 to 13.4%. Acceptable intra-day and inter-day accuracies, ranging from 80 to 124%, were obtained for sarcosine and the other metabolites. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Urinary proteomics based on capillary electrophoresis coupled to mass spectrometry in kidney disease.

    PubMed

    Albalat, Amaya; Franke, Julia; Gonzalez, Julien; Mischak, Harald; Zürbig, Petra

    2013-01-01

    Urine is an excellent sample source in the proteomic study of diseases. It is available in large quantities, is relatively stable, is not contaminated by cells or lipids, and has shown to provide information not only on the organs in contact with the urinary tract but also of more remote organs and tissues. In addition to these qualities, it can be collected by untrained personnel. For these reasons, urinary proteomic studies have escalated in recent years with the aim of identifying biomarkers that could be use for diagnosis or to predict the outcome of renal pathologies. In this chapter, we present one of the analytical platforms that has been successfully used in a number of studies for the identification and validation of biomarkers in kidney diseases. This technique is capillary electrophoresis coupled online to an electrospray ionization time-of-flight mass spectrometer (CE-MS). This technology has proven to be highly reproducible, sensitive with a quick analysis time, important features when analytical platforms have to be used in a clinical setting.

  5. Analysis of galanthamine-type alkaloids by capillary gas chromatography-mass spectrometry in plants.

    PubMed

    Berkov, Strahil; Bastida, Jaume; Viladomat, Francesc; Codina, Carles

    2008-01-01

    Galanthamine, an acetylcholinesterase inhibitor used for the treatment of Alzheimer's disease, and galanthamine-type alkaloids are synthesised in different plants of the family Amaryllidaceae. A capillary gas chromatographic-mass spectroscopic (CGC-MS) method for the separation of 7 galanthamine type alkaloids, including galanthamine and epigalanthamine, is described in the present paper. A simple method for the routine quantification of galanthamine in plants was developed using pre-packed columns with diatomaceous earth (Isolute HM-N), allowing simultaneous preparation of a large number of samples. Galanthamine showed excellent linearity in the range from 50 to 1000 microg/mL and the limit of quantification was 5 microg/mL in total ion current mode and 1.6 ng/mL in selected ion monitoring mode. The recovery of galanthamine was more than 90%. Interday reproducibility (RSD) of the extraction was 2.74%. A method to find and to microextract Amaryllidaceae alkaloids in low-mass plant samples is also described.

  6. Improvement of Mitochondria Extract from Saccharomyces cerevisiae Characterization in Shotgun Proteomics Using Sheathless Capillary Electrophoresis Coupled to Tandem Mass Spectrometry

    PubMed Central

    Ibrahim, Marianne; Gahoual, Rabah; Enkler, Ludovic; Becker, Hubert Dominique; Chicher, Johana; Hammann, Philippe; François, Yannis-Nicolas; Kuhn, Lauriane; Leize-Wagner, Emmanuelle

    2016-01-01

    In this work, we describe the characterization of a quantity-limited sample (100 ng) of yeast mitochondria by shotgun bottom-up proteomics. Sample characterization was carried out by sheathless capillary electrophoresis, equipped with a high sensitivity porous tip and coupled to tandem mass spectrometry (CESI–MS-MS) and concomitantly with a state-of-art nano flow liquid chromatography coupled to a similar mass spectrometry (MS) system (nanoLC–MS-MS). With single injections, both nanoLC–MS-MS and CESI–MS-MS 60 min-long separation experiments allowed us to identify 271 proteins (976 unique peptides) and 300 proteins (1,765 unique peptides) respectively, demonstrating a significant specificity and complementarity in identification depending on the physicochemical separation employed. Such complementary, maximizing the number of analytes detected, presents a powerful tool to deepen a biological sample's proteomic characterization. A comprehensive study of the specificity provided by each separating technique was also performed using the different properties of the identified peptides: molecular weight, mass-to-charge ratio (m/z), isoelectric point (pI), sequence coverage or MS–MS spectral quality enabled to determine the contribution of each separation. For example, CESI–MS-MS enables to identify larger peptides and eases the detection of those having extreme pI without impairing spectral quality. The addition of peptides, and therefore proteins identified by both techniques allowed us to increase significantly the sequence coverages and then the confidence of characterization. In this study, we also demonstrated that the two yeast enolase isoenzymes were both characterized in the CESI–MS-MS data set. The observation of discriminant proteotypic peptides is facilitated when a high number of precursors with high-quality MS–MS spectra are generated. PMID:26860395

  7. Monitoring of cefepime in human serum and plasma by micellar electrokinetic capillary chromatography: Improvement of sample preparation and validation by liquid chromatography coupled to mass spectrometry.

    PubMed

    Šestáková, Nela; Theurillat, Regula; Sendi, Parham; Thormann, Wolfgang

    2017-02-20

    Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic capillary chromatography and liquid chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic capillary chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic capillary chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic capillary chromatography could thereby be validated. This article is protected by copyright. All rights reserved.

  8. Quantitative twoplex glycan analysis using (12)C6 and (13)C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

    PubMed

    Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

    2016-12-01

    Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available (12/13)C6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for (12)C6 'light' and (13)C6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

  9. Determination of chiral pharmaceutical compounds, terbutaline, ketamine and propranolol, by on-line capillary electrophoresis-electrospray ionization mass spectrometry.

    PubMed

    Lu, W; Cole, R B

    1998-08-28

    On-line capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) has been employed for the determination of racemic mixtures of the chiral drugs, terbutaline, ketamine, and propranolol. Separation of the different chiral forms has been achieved by introducing cyclodextrins (CDs), which act as chiral selectors, into the CE operating electrolytes. Cyclodextrins function as chiral selectors in CE because of their ability to form host-guest complexes (inclusion complexes) of varying stability with an array of chiral drugs and other compounds. Derivatized forms of beta-CD (i.e., dimethyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin) were used in this study due to their higher solubilities in the aqueous methanolic operating electrolyte than native beta-CD. Addition of minor quantities of methanol to the aqueous-based CE operating electrolytes improved the stability of electrospray ionization conditions and further enhanced CE resolution of the enantiomeric pairs relative to purely aqueous systems. Introduction of the CDs into the CE operating electrolytes caused suppression of analyte signals in ESI-MS, and the dependence of analyte signal intensities on the solution concentrations of the derivatized beta-CDs was examined. Under optimized conditions, the different enantiomeric forms of the compounds under investigation were successfully separated and detected by CE-ESI-MS.

  10. Feasibility of capillary liquid chromatography-microchip-atmospheric pressure photoionization-mass spectrometry for pesticide analysis in tomato.

    PubMed

    Kruve, Anneli; Haapala, Markus; Saarela, Ville; Franssila, Sami; Kostiainen, Risto; Kotiaho, Tapio; Ketola, Raimo A

    2011-06-24

    A new and sensitive analytical method, using capillary liquid chromatography (capLC) with a microfabricated heated nebulizer chip for atmospheric pressure photoionization and tandem mass spectrometry (μAPPI-MS/MS), was developed for the analysis of selected carbamate pesticides in a tomato matrix. The performance of the instrumental method was evaluated, using seven pesticides, namely oxamyl, methomyl, aldicarb, carbofuran, pirimicarb, thiocarb, and ditalimfos. The limits of detection achieved with the capLC-μAPPI-MS/MS method in the positive ion mode were low, ranging from 0.25 ng mL(-1) for pirimicarb to 5 ng mL(-1) for oxamyl and methomyl, corresponding to 5 and 0.25 μg kg(-1) for tomato samples, respectively, which are clearly below the maximum residue limits for them in fruits and vegetables. The repeatability of the instrumental method ranged from 2.9 to 13.9% (RSD) at a low (0.05 μg mL(-1)) concentration level. An adequate linearity (r(2)=0.984-0.999) at a concentration range from 0.005 to 5.0 μg mL(-1) was observed for all pesticides. The results obtained show that the capLC-μAPPI-MS/MS method developed could be used for the analysis of selected pesticides from tomato.

  11. Capillary electrophoresis with UV detection and mass spectrometry in method development for profiling metabolites of steroid hormone metabolism.

    PubMed

    Sirén, Heli; Seppänen-Laakso, Tuulikki; Oresic, Matej

    2008-08-15

    The aim of this study was to develop a method for comprehensive profiling of metabolites involved in mammalian steroid metabolism. The study was performed using the partial filling micellar electrokinetic chromatography (PF-MEKC) technique for determination of endogenous low-hydrophilic steroids. The detection techniques in capillary electrophoresis were UV absorption and electrospray mass spectrometry (ESI-MS). Thirteen steroids were included in the method development, and the selected were metabolites involved in major pathways of steroid biosynthesis. Although only eight of them could be separated and detected with UV, they could be identified by ESI-MS using selected ion monitoring (SIM) technique. Tandem MS spectra were also collected. UV detection was more sensitive than MS due to better separation of compounds and the selective signal sensitivity. The lowest limits of detection were 10-100 ng/mL for cortisone, corticosterone, hydrocortisone and testosterone. The other steroids could be detected at 500-1000 ng/mL. The identification of cortisone, corticosterone, hydrocortisone, estrogen and testosterone were made in patient urine samples and their concentrations were 1-40 microg/L.

  12. Profiling B-Type Natriuretic Peptide Cleavage Peptidoforms in Human Plasma by Capillary Electrophoresis with Electrospray Ionization Mass Spectrometry.

    PubMed

    Zhang, Shenyan; Raedschelders, Koen; Santos, Marcia; Van Eyk, Jennifer E

    2017-10-02

    B-type Natriuretic Peptide (BNP) is a biologically active circulating hormone. Plasma concentrations of BNP are routinely used in the diagnosis of heart failure, and the intravenous infusion of recombinant BNP can be used for heart failure treatment. Like many bioactive polypeptides, multiple plasma enzymes are known to cleave circulating BNP, and as part of the CVD-B/D-HPP mandate, we sought to develop a technique capable of profiling these catabolic processes in plasma. We used a neutral-coated capillary electrophoresis-electrospray ionization (CESI) separation system coupled with high-resolution mass spectrometry to profile the proteolysis of exogenous recombinant BNP1-32 in plasma. Our method utilizes electrokinetic injection of minimally processed plasma samples to simultaneously monitor the dynamic generation and breakdown of at least five BNP peptidoforms in plasma. By integrating multisegment injection, our method can produce a multipoint BNP proteolytic profile for one sample within an hour. We envision applying this method to assess the potential relation between plasma-based BNP proteolysis and heart failure as well as a means of monitoring BNP bioavailability after therapeutic infusion.

  13. Enantiomeric separation of free L- and D-amino acids in hydrolyzed protein fertilizers by capillary electrophoresis tandem mass spectrometry.

    PubMed

    Sánchez-Hernández, Laura; Serra, Nuria Sierras; Marina, María Luisa; Crego, Antonio L

    2013-05-29

    Two capillary electrophoresis-tandem mass spectrometry (CE-MS(2)) methods were optimized in this work using cyclodextrins (CDs) as chiral selectors in order to determine the degree of racemization of the free amino acids contained in different hydrolyzed protein fertilizers used as plant biostimulants. The methodologies developed were characterized by the specificity of MS(2) experiments enabling the identification of all protein amino acids, except for cysteine. The enantiomeric separation of up to 14 amino acids was achieved with resolutions above 1.0 and limits of detection between 0.02 and 0.8 μM. The methods were applied to the analysis of complex samples such as hydrolyzed protein fertilizers to evaluate the presence of d-amino acids after different kinds of hydrolysis treatments. The results corroborated the absence or almost negligible presence of enantiomeric conversions of the L-amino acids into D-amino acids in the case of fertilizers obtained by enzymatic hydrolysis, as well as the high racemization rate for those obtained through a chemical hydrolysis.

  14. Fast top-down intact protein characterization with capillary zone electrophoresis-electrospray ionization tandem mass spectrometry

    PubMed Central

    Sun, Liangliang; Knierman, Michael D.; Zhu, Guijie; Dovichi, Norman J.

    2013-01-01

    Capillary zone electrophoresis (CZE)-electrospray ionization-tandem mass spectrometry (ESI-MS/MS) was applied for rapid top-down intact protein characterization. A mixture containing four model proteins (cytochrome c, myoglobin, bovine serum albumin (BSA) and beta casein) was used as the sample. The CZE-ESI-MS system was first evaluated with the mixture. The four model proteins and five impurities were baseline separated within 12 min. The limits of detection (s/n = 3) of the four model proteins ranged from 20 amole (cytochrome c) to 800 amole (BSA). The relative standard deviations of migration time and intensity for the four model proteins were less than 3% and 30%, respectively, in quintuplicate runs. CZE-ESI-MS/MS was then applied for top-down characterization of the mixture. Three of the model proteins (all except BSA) and an impurity (bovine transthyretin) were confidently identified by database searching of the acquired tandem spectra from protein fragmentation. Modifications including phosphorylation, N-terminal acetylation, and heme group binding were identified. PMID:23692435

  15. Complexation of europium and uranium by humic acids analyzed by capillary electrophoresis-inductively coupled plasma mass spectrometry.

    PubMed

    Möser, Christina; Kautenburger, Ralf; Philipp Beck, Horst

    2012-05-01

    Investigations of the mobility of radioactive and nonradioactive substances in the environment are important tasks for the development of a future disposal in deep geological formations. Dissolved organic matter (DOM) can play an important role in the mobilization of metal ions due to complexation. In this study, we investigate the complexation behavior of humic acid (HA) as a model substance for DOM and its influence on the migration of europium as homologue for the actinide americium and uranium as the principal component of nuclear fuel. As speciation technique, capillary electrophoresis (CE) was hyphenated with inductively coupled plasma mass spectrometry (ICP-MS). For the study, 0.5 mg·L⁻¹ of the metals and 25 mg·L⁻¹ of (purified Aldrich) HA and an aqueous solution sodium-perchlorate with an ionic strength of 10 mM at pH 5 were used. CE-ICP-MS clearly shows the different speciation of the triple positively charged europium and the double positively charged uranyl cation with HA. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Analysis of metabolomic profile of fermented Orostachys japonicus A. Berger by capillary electrophoresis time of flight mass spectrometry

    PubMed Central

    Das, Gitishree; Patra, Jayanta Kumar; Lee, Sun-Young; Kim, Changgeon; Park, Jae Gyu

    2017-01-01

    Microbial cell performance in food biotechnological processes has become an important concern for improving human health worldwide. Lactobacillus plantarum, which is widely distributed in nature, is a lactic acid bacterium with many industrial applications for fermented foods or functional foods (e.g., probiotics). In the present study, using capillary electrophoresis time of flight mass spectrometry, the metabolomic profile of dried Orostachys japonicus A. Berger, a perennial medicinal herb with L. plantarum was compared with that of O. japonicus fermented with L. plantarum to elucidate the metabolomic changes induced by the fermentation process. The levels of several metabolites were changed by the fermentation process, indicating their involvement in microbial performance. For example, glycolysis, the pentose phosphate pathway, the TCA cycle, the urea cycle-related metabolism, nucleotide metabolism, and lipid and amino acid metabolism were altered significantly by the fermentation process. Although the fermented metabolites were not tested using in vivo studies to increase human health benefits, our findings provide an insight into the alteration of metabolites induced by fermentation, and indicated that the metabolomic analysis for the process should be accompanied by fermenting strains and conditions. PMID:28704842

  17. Analysis of metabolomic profile of fermented Orostachys japonicus A. Berger by capillary electrophoresis time of flight mass spectrometry.

    PubMed

    Das, Gitishree; Patra, Jayanta Kumar; Lee, Sun-Young; Kim, Changgeon; Park, Jae Gyu; Baek, Kwang-Hyun

    2017-01-01

    Microbial cell performance in food biotechnological processes has become an important concern for improving human health worldwide. Lactobacillus plantarum, which is widely distributed in nature, is a lactic acid bacterium with many industrial applications for fermented foods or functional foods (e.g., probiotics). In the present study, using capillary electrophoresis time of flight mass spectrometry, the metabolomic profile of dried Orostachys japonicus A. Berger, a perennial medicinal herb with L. plantarum was compared with that of O. japonicus fermented with L. plantarum to elucidate the metabolomic changes induced by the fermentation process. The levels of several metabolites were changed by the fermentation process, indicating their involvement in microbial performance. For example, glycolysis, the pentose phosphate pathway, the TCA cycle, the urea cycle-related metabolism, nucleotide metabolism, and lipid and amino acid metabolism were altered significantly by the fermentation process. Although the fermented metabolites were not tested using in vivo studies to increase human health benefits, our findings provide an insight into the alteration of metabolites induced by fermentation, and indicated that the metabolomic analysis for the process should be accompanied by fermenting strains and conditions.

  18. Simultaneous analysis of vitamins B in pharmaceuticals and dietary supplements by capillary electrophoresis hyphenated with triple quadrupole mass spectrometry.

    PubMed

    Maráková, K; Piestanský, J; Havránek, E; Mikus, P

    2014-09-01

    The advanced hyphenated method based on capillary electrophoresis (CE) on-line combined with electrospray ionization (ESI) and tandem mass spectrometry (MS/MS, here triple quadrupole, QqQ) was developed and applied in pharmaceutical analysis in this work. Under the optimized CE separation (background electrolyte: 50 mmol/L formic acid with pH 2.05), ESI ionization (sheath liquid: 0.1% v/v formic acid in 50% v/v aq methanol) and QqQ detection (100-160V fragmentor voltage, 15-25eV collision energy, depending on the type of analyte) conditions, highly efficient, reproducible, accurate, sensitive (sub microg/mL LODs) and selective (each analyte was unequivocally specified by two characteristic MS signals, i.e. qualifier, quantifier) determination of vitamins B was achieved. All vitamins B, namely thiamine, riboflavin, nicotinamide, nicotinic acid, pantothenic acid, pyridoxine, biotin, folic acid and cyanocobalamine, were simultaneously determined in various dosage forms (injection solution, tablets, and effervescent tablets) within ca. 16 min. The main benefits of the proposed CE-ESI-QqQ method in comparison with the CE-UV ones are considerably enhanced sensitivity and selectivity. Other benefits are low cost, simplicity, flexibility and environmental aspects when comparing CE-ESI-QqQ with HPLC-MS. Successful validation and application of the proposed CE-ESI-QqQ method suggest its routine use in highly effective and reliable multi-drug quality control.

  19. Complexation studies with lanthanides and humic acid analyzed by ultrafiltration and capillary electrophoresis-inductively coupled plasma mass spectrometry.

    PubMed

    Kautenburger, Ralf; Beck, Horst Philipp

    2007-08-03

    For the long-term storage of radioactive waste, detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is necessary. Humic acid (HA) can play an important role in the immobilisation or mobilisation of metal ions due to complexation and colloid formation. Therefore, we investigate the complexation behavior of HA and its influence on the migration or retardation of selected lanthanides (europium and gadolinium as homologues of the actinides americium and curium). Two independent speciation techniques, ultrafiltration and capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS) have been compared for the study of Eu and Gd interaction with (purified Aldrich) HA. The degree of complexation of Eu and Gd in 25 mg l(-1) Aldrich HA solutions was determined with a broad range of metal loading (Eu and Gd total concentration between 10(-6) and 10(-4) mol l(-1)), ionic strength of 10 mM (NaClO4) and different pH-values. From the CE-ICP-MS electropherograms, additional information on the charge of the Eu species was obtained by the use of 1-bromopropane as neutral marker. To detect HA in the ICP-MS and separate between HA complexed and non complexed metal ions in the CE-ICP-MS, we have halogenated the HA with iodine as ICP-MS marker.

  20. Capillary gas chromatography coupled with microplasma mass spectrometry for organotin speciation.

    PubMed

    Brede, C; Pedersen-Bjergaard, S; Lundanes, E; Greibrokk, T

    1999-07-23

    Gas chromatography was coupled with microplasma mass spectrometry for selective detection of organotin compounds. The microplasma ion source was a capacitively coupled radiofrequency helium plasma, which was located inside the high vacuum area of the mass spectrometer. Only 1-3 ml min-1 of helium carrier gas from the gas chromatograph was necessary for sustaining the plasma while 0.15-1.5 ml min-1 of hydrogen was added as reagent gas. Hydrogen was applied for prevention of carbon deposition and served to minimize the interactions between tin and the fused-silica inner surface of the microplasma ion source. Both carbon and tin were detected as positively charged atomic ions, which were expelled from the microplasma ion source and directly focused by electrostatic lenses towards the quadrupole mass analyzer. Tin exhibited high selectivity to carbon (> 10(4)) and a detection limit of 3.5 pg s-1.

  1. Characterization of Coordination Complexes by Desorption Electrospray Mass Spectrometry with a Capillary Target

    SciTech Connect

    Gary S. Groenewold; Anthony D. Appelhans; Michael E. McIlwain; Garold L. Gresham

    2011-03-01

    Metal coordination complexes were formed directly from liquid surfaces using desorption electrospray ionization (DESI) mass spectrometry. The approach is attractive because it separates complexities of ESI spray droplet formation from delivery of the analyte solution, and thereby gets around difficulty resulting from alteration of the spray process by changes in solution chemistry. Cs+, Ba2+, and La3+ coordination complexes were formed using 18-crown-6 (18c6) and triethylphosphate (TEP) as ligands (L), that had the general formula [Mn+(NO3-)n-1(L)m]+. Formation of singly charged cation complexes was preferred, with charge reduction at the metal site accomplished by attachment of nitrate. Using TEP as a model phosphoryl ligand, alkali metals coordinate with up to three ligands, with Cs+ preferring fewer than Na+. Ba2+ and La3+ are formed as ion pair complexes [Ba(NO3)]+ and [La(NO3)2]+, and both will coordinate with up to four TEP ligands. Using 18c6, Cs+ forms a bis-ligand complex. In contrast, [Ba(NO3)]+ prefers a single 18c6 ligand, while La forms mainly [La(NO3)2(18c6)]+, for which DFT calculations suggested a structure in which the nitrate ligands occupy pseudo-axial positions on opposing sides of the crown. Lower abundances of bis-18c6 complexes were also formed together with doubly charged [La(NO3)(18c6)n]2+ complexes (n = 2 – 4). The results suggest an alternative strategy for probing metal speciation in solution that is less perturbed by the droplet formation and ionization mechanisms operating in conventional electrospray ionization mass spectrometry.

  2. Determination and quantification of cations in ionic liquids by capillary electrophoresis-mass spectrometry.

    PubMed

    Pyschik, Marcelina; Winter, Martin; Nowak, Sascha

    2017-02-17

    In this study, a capillary electrophoresis (CE) method hyphenated to a high-resolution mass spectrometer is presented to detect the cations in ionic liquids (ILs) and their decomposition products. The investigated ILs were 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM TFSI). With this method, it was possible to achieve baseline separation of the decomposition products from the main cations in short migration times. Because of the successful baseline separation, it was also possible to quantify the main cations in ILs, which were aged at room temperature and at 60°C. Additionally, the relative standard deviations (RSDs) for the concentrations of the main cations investigated by CE and ion chromatography (IC) were given to compare the both methods with each other. The concentrations were determined for the main cations aged at different temperatures. Finally, the limits of detection (LOD) and quantification (LOQ) were calculated for this method and compared to the IC results. The LODs and LOQs for CE method was in the range of 0.3-2.1mg/kg and for the IC method 34.9-455.2mg/kg. Therefore, more decomposition products of EMIM(+) were determined by the CE method than by the IC method. In each investigated IL, more decomposition products of the cations were detected at 60°C compared to room temperature. The PYR14(+) concentration decreased by 4 % at 60°C, while PYR13(+) and EMIM(+) decreased more than 10 % aged at 60°C in contrast to the sample which was aged at room temperature.

  3. Capillary electrophoresis mass spectrometry as a potential tool to detect lithium-induced nephropathy: Preliminary results.

    PubMed

    Raedler, Thomas J; Wittke, Stefan; Jahn, Holger; Koessler, Andreas; Mischak, Harald; Wiedemann, Klaus

    2008-04-01

    Lithium remains the treatment of choice for many patients suffering from bipolar disorder. However, long-term treatment with lithium carries the potential to cause renal and thyroid dysfunction. Lithium-induced nephropathies are characterised by deterioration of urinary concentrating ability as well as, less frequently, a progressive and potentially irreversible decrease in glomerular filtration rate (GFR). Pathological changes after treatment with lithium include both tubulointerstitial and glomerular changes. Besides monitoring of the kidney-function, no screening-instruments exist for early identification of patients at risk of lithium-induced nephropathy. CE-MS (capillary electrophoresis coupled to a mass spectrometer) is a new technique that has been applied to the differential diagnosis of nephropathies. We sought to determine if CE-MS can be used to identify lithium-induced renal changes. A urine-sample was obtained from 14 subjects (7 males, 7 females, mean age 51.1 years) under long-term treatment with lithium (mean duration 17.4 years, range 8-35 years) without known nephropathy (mean creatinine 0.96 mg/dl; range 0.7-1.6). Urine samples were stored at -20 degrees C until analysis. CE-MS was performed according to standard procedures and a screen for nephropathies was used. Among the 14 urine samples, two subjects tested positive for a nephropathy. One further subject had a borderline result. Since 3/14 subjects with no known nephropathy showed some degree of pathological findings, CE-MS from a urine-sample may be helpful for the early detection of renal damage under treatment with lithium. However, a specific screen for lithium-induced nephropathies still needs to be developed.

  4. Capillary gas chromatography-mass spectrometry of volatile and semi-volatile compounds of Salvia officinalis.

    PubMed

    Radulescu, Valeria; Chiliment, Silvia; Oprea, Eliza

    2004-02-20

    The essential oil and infusion of Salvia officinalis leaves have been widely applied in traditional medicine since ancient times and nowadays subjected to extensive research of their antibacterial, antiviral and cytotoxic properties. This paper shows chemical composition data of S. officinalis leaves essential oil isolated by steam distillation using a Clevenger-type apparatus. Also, the paper presents the chemical content of volatile and semi-volatile compounds of S. officinalis leaves infusion. The volatile and semi-volatile compounds of S. officinalis leaves infusion were isolated by solid-phase extraction (SPE) and liquid-liquid extraction with hexane and dichloromethane. SPE was carried out on 500 mg octadecylsilane (C18) cartridges and elution with dichloromethane. Liquid-liquid extraction was performed with hexane and dichloromethane. The essential oil in dichloromethane and infusion extracts in hexane and dichloromethane were analyzed by gas chromatography coupled with mass spectrometry. The quantitative results obtained by solid-phase extraction and liquid-liquid extraction showed that SPE on C18 performed the highest recovery of the volatile compounds from infusion sample.

  5. Sensitive redox speciation of iron, neptunium, and plutonium by capillary electrophoresis hyphenated to inductively coupled plasma sector field mass spectrometry.

    PubMed

    Graser, Carl-Heinrich; Banik, Nidhu Lal; Bender, Kerstin Anne; Lagos, Markus; Marquardt, Christian Michael; Marsac, Rémi; Montoya, Vanessa; Geckeis, Horst

    2015-10-06

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of actinide (geo)chemistry. Advanced analytical tools are required to gain insight into actinide speciation in a given system. The geochemical conditions in the vicinity of a nuclear repository control the redox state of radionuclides, which in turn has a strong impact on their mobility. Besides the long-lived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox-related geochemical processes. Measuring the oxidation state distribution for redox sensitive radionuclides and other metal ions is challenging at trace concentrations below the detection limit of most available spectroscopic methods (≥10(-6) M). Consequently, ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) is a suitable separation method for metal cations. CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE-ICP-SF-MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI), and Fe (II, III) at concentrations lower than 10(-7) M. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. We obtain detection limits of 10(-12) M for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate-based electrolyte system. The separation of Fe (II) and Fe (III) was investigated using different organic complexing ligands, EDTA, and o-phenanthroline. For the Fe redox system, a limit of detection of 10(-8) M was calculated. By applying this analytical system to sorption studies, we were able to underline previously published results for the sorption behavior of Np in highly diluted concentrations, and

  6. Enantioselective capillary electrophoresis-mass spectrometry of amino acids in cerebrospinal fluid using a chiral derivatizing agent and volatile surfactant.

    PubMed

    Prior, A; Moldovan, R C; Crommen, J; Servais, A C; Fillet, M; de Jong, G J; Somsen, G W

    2016-10-12

    The sensitivity of coupled enantioselective capillary electrophoresis-mass spectrometry (CE-MS) of amino acids (AAs) is often hampered by the chiral selectors in the background electrolyte (BGE). A new method is presented in which the use of a chiral selector is circumvented by employing (+)-1-(9-fluorenyl)ethyl chloroformate (FLEC) as chiral AA derivatizing agent and ammonium perfluorooctanoate (APFO) as a volatile pseudostationary phase for separation of the formed diastereomers. Efficient AA derivatization with FLEC was completed within 10 min. Infusion experiments showed that the APFO concentration hardly affects the MS response of FLEC-AAs and presents significantly less ion suppression than equal concentrations of ammonium acetate. The effect of the pH and APFO concentration of the BGE and the capillary temperature were studied in order to achieve optimized enantioseparation. Optimization of CE-MS parameters, such as sheath-liquid composition and flow rate, ESI and MS settings was performed in order to prevent analyte fragmentation and achieve sensitive detection. Selective detection and quantification of 14 chiral proteinogenic AAs was achieved with chiral resolution between 1.2 and 8.6, and limits of detection ranging from 130 to 630 nM injected concentration. Aspartic acid and glutamic acid were detected, but not enantioseparated. The optimized method was applied to the analysis of chiral AAs in cerebrospinal fluid (CSF). Good linearity (R(2) > 0.99) and acceptable peak area and electrophoretic mobility repeatability (RSDs below 21% and 2.4%, respectively) were achieved for the chiral proteinogenic AAs, with sensitivity and chiral resolution mostly similar to obtained for standard solutions. Next to l-AAs, endogenous levels of d-serine and d-glutamine could be measured in CSF revealing enantiomeric ratios of 4.8%-8.0% and 0.34%-0.74%, respectively, and indicating the method's potential for the analysis of low concentrations of d-AAs in presence of

  7. Third-generation electrokinetically pumped sheath-flow nanospray interface with improved stability and sensitivity for automated capillary zone electrophoresis-mass spectrometry analysis of complex proteome digests.

    PubMed

    Sun, Liangliang; Zhu, Guijie; Zhang, Zhenbin; Mou, Si; Dovichi, Norman J

    2015-05-01

    We have reported a set of electrokinetically pumped sheath flow nanoelectrospray interfaces to couple capillary zone electrophoresis with mass spectrometry. A separation capillary is threaded through a cross into a glass emitter. A side arm provides fluidic contact with a sheath buffer reservoir that is connected to a power supply. The potential applied to the sheath buffer drives electro-osmosis in the emitter to pump the sheath fluid at nanoliter per minute rates. Our first-generation interface placed a flat-tipped capillary in the emitter. Sensitivity was inversely related to orifice size and to the distance from the capillary tip to the emitter orifice. A second-generation interface used a capillary with an etched tip that allowed the capillary exit to approach within a few hundred micrometers of the emitter orifice, resulting in a significant increase in sensitivity. In both the first- and second-generation interfaces, the emitter diameter was typically 8 μm; these narrow orifices were susceptible to plugging and tended to have limited lifetime. We now report a third-generation interface that employs a larger diameter emitter orifice with very short distance between the capillary tip and the emitter orifice. This modified interface is much more robust and produces much longer lifetime than our previous designs with no loss in sensitivity. We evaluated the third-generation interface for a 5000 min (127 runs, 3.5 days) repetitive analysis of bovine serum albumin digest using an uncoated capillary. We observed a 10% relative standard deviation in peak area, an average of 160,000 theoretical plates, and very low carry-over (much less than 1%). We employed a linear-polyacrylamide (LPA)-coated capillary for single-shot, bottom-up proteomic analysis of 300 ng of Xenopus laevis fertilized egg proteome digest and identified 1249 protein groups and 4038 peptides in a 110 min separation using an LTQ-Orbitrap Velos mass spectrometer; peak capacity was ∼330. The

  8. Comparing capillary electrophoresis-mass spectrometry fingerprints of urine samples obtained after intake of coffee, tea, or water.

    PubMed

    Allard, Erik; Bäckström, Daniel; Danielsson, Rolf; Sjöberg, Per J R; Bergquist, Jonas

    2008-12-01

    Metabolomic fingerprinting is a growing strategy for characterizing complex biological samples without detailed prior knowledge about the metabolic system. A two-way analysis system with liquid separation and mass spectrometric detection provides detail-rich data suitable for such fingerprints. As a model study, human urine samples, obtained after intake of coffee, tea, or water, were analyzed with capillary electrophoresis electrospray ionization time-of-flight mass spectrometry (CE-ESI-TOF-MS). In-house-developed software (in Matlab) was utilized to manage and explore the large amount of data acquired (230 CE-MS runs, each with 50-100 million nonzero data points). After baseline and noise reduction, followed by suitable binning in time and m/z, the data sets comprised 9 and 14 million data points in negative and positive ESI mode, respectively. Finally, a signal threshold was applied, further reducing the number to about 100 000 data points per data set. A set of interactive exploratory tools, utilizing principal component analysis (PCA) and analysis of variance (ANOVA) results based on a general linear model, facilitated visual interpretation with score plots (for group assessment) and differential fingerprints (for "hot spot" detection). In the model study highly significant differences due to beverage intake were obtained among the 10 first principal components (p < 10(-6) for two of the components in both ESI modes). Especially, the contrasts between "coffee" and "tea or water" indicated several "hot spots" with highly elevated intensities (e.g., for uncharged masses 93, 94, 109, 119, 123, 132, 148, 169, 178, 187, 190, and 193) suitable for further analysis, for example, with tandem MS.

  9. Identification of new oxycodone metabolites in human urine by capillary electrophoresis-multiple-stage ion-trap mass spectrometry.

    PubMed

    Baldacci, A; Caslavska, J; Wey, A B; Thormann, W

    2004-10-08

    Capillary electrophoresis-electrospray ionization multiple-stage ion-trap mass spectrometry (CE-MSn) and computer simulation of fragmentation are demonstrated to be effective tools to detect and identify phase I and phase II metabolites of oxycodone (OCOD) in human urine. OCOD is a strong analgesic used for the management of moderate to severe mainly postoperative or cancer-related pain whose metabolism in man is largely unknown. Using an aqueous pH 9 ammonium acetate buffer and CE-MSn (n < or = 5), OCOD and its phase I metabolites produced by O-demethylation, N-demethylation, 6-ketoreduction and N-oxidation (such as oxymorphone, noroxycodone, noroxymorphone, 6-oxycodol, nor-6-oxycodol, oxycodone-N-oxide and 6-oxycodol-N-oxide) and phase II conjugates with glucuronic acid of several of these compounds could be detected in alkaline solid-phase extracts of a patient urine that was collected during a pharmacotherapy episode with daily ingestion of 240-320 mg of OCOD chloride. The data for three known OCOD metabolites for which the standards had to be synthesized in-house, 6-oxycodol, nor-6-oxycodol and oxycodone-N-oxide, were employed to identify two new metabolites, the N-oxidized derivative of 6-oxycodol and an O-glucuronide of this compound. CE-MSn and computer simulation of fragmentation also led to the identification of the N-glucuronide of noroxymorphone, another novel OCOD metabolite for which no standard compound or mass spectra library data were available.

  10. Assessing Gibberellins Oxidase Activity by Anion Exchange/Hydrophobic Polymer Monolithic Capillary Liquid Chromatography-Mass Spectrometry

    PubMed Central

    Liu, Jiu-Feng; Wu, Yan; Feng, Yu-Qi; Yuan, Bi-Feng

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography – mass spectrometry (cLC-MS) method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20). An anion exchange/hydrophobic poly([2-(methacryloyloxy)ethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate)(META-co-DVB-co-EDMA) monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3) of GAs were in the range of 0.62–0.90 fmol. We determined the kinetic parameters (Km) of recombinant GA3-oxidase in Escherichia coli (E. coli) cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology. PMID:23922762

  11. Tapered-Tip Capillary Electrophoresis Nano-Electrospray Ionization Mass Spectrometry for Ultrasensitive Proteomics: the Mouse Cortex

    NASA Astrophysics Data System (ADS)

    Choi, Sam B.; Zamarbide, Marta; Manzini, M. Chiara; Nemes, Peter

    2017-04-01

    Ultrasensitive characterization of the proteome raises the potential to understand how differential gene expression orchestrates cell heterogeneity in the brain. Here, we report a microanalytical capillary electrophoresis nano-flow electrospray ionization (CE-nanoESI) interface for mass spectrometry to enable the measurement of limited amounts of proteins in the mouse cortex. Our design integrates a custom-built CE system to a tapered-tip metal emitter in a co-axial sheath-flow configuration. This interface can be constructed in <15 min using readily available components, facilitating broad adaptation. Tapered-tip CE-nanoESI generates stable electrospray by reproducibly anchoring the Taylor cone, minimizes sample dilution in the ion source, and ensures efficient ion generation by sustaining the cone-jet spraying regime. Parallel reaction monitoring provided a 260-zmol lower limit of detection for angiotensin II (156,000 copies). CE was able to resolve a complex mixture of peptides in 330,000 theoretical plates and identify 15 amol ( 1 pg) of BSA or cytochrome c. Over 30 min of separation, 1 ng protein digest from the mouse cortex yielded 217 nonredundant proteins encompassing a 3-log-order concentration range using a quadrupole time-of-flight mass spectrometer. Identified proteins included many products from genes that are traditionally used to mark oligodendrocytes, astrocytes, and microglia. Finally, key proteins involved in neurodegenerative disorders were detected (e.g., parkinsonism and spastic paraplegia). CE-nanoESI-HRMS delivers sufficient sensitivity to detect proteins in limited amounts of tissues and cell populations to help understand how gene expression differences maintain cell heterogeneity in the brain.

  12. Tapered-Tip Capillary Electrophoresis Nano-Electrospray Ionization Mass Spectrometry for Ultrasensitive Proteomics: the Mouse Cortex.

    PubMed

    Choi, Sam B; Zamarbide, Marta; Manzini, M Chiara; Nemes, Peter

    2016-11-16

    Ultrasensitive characterization of the proteome raises the potential to understand how differential gene expression orchestrates cell heterogeneity in the brain. Here, we report a microanalytical capillary electrophoresis nano-flow electrospray ionization (CE-nanoESI) interface for mass spectrometry to enable the measurement of limited amounts of proteins in the mouse cortex. Our design integrates a custom-built CE system to a tapered-tip metal emitter in a co-axial sheath-flow configuration. This interface can be constructed in <15 min using readily available components, facilitating broad adaptation. Tapered-tip CE-nanoESI generates stable electrospray by reproducibly anchoring the Taylor cone, minimizes sample dilution in the ion source, and ensures efficient ion generation by sustaining the cone-jet spraying regime. Parallel reaction monitoring provided a 260-zmol lower limit of detection for angiotensin II (156,000 copies). CE was able to resolve a complex mixture of peptides in ~330,000 theoretical plates and identify ~15 amol (~1 pg) of BSA or cytochrome c. Over 30 min of separation, 1 ng protein digest from the mouse cortex yielded 217 nonredundant proteins encompassing a ~3-log-order concentration range using a quadrupole time-of-flight mass spectrometer. Identified proteins included many products from genes that are traditionally used to mark oligodendrocytes, astrocytes, and microglia. Finally, key proteins involved in neurodegenerative disorders were detected (e.g., parkinsonism and spastic paraplegia). CE-nanoESI-HRMS delivers sufficient sensitivity to detect proteins in limited amounts of tissues and cell populations to help understand how gene expression differences maintain cell heterogeneity in the brain. Graphical Abstract ᅟ.

  13. Determination of glycoalkaloids and relative aglycones by nonaqueous capillary electrophoresis coupled with electrospray ionization-ion trap mass spectrometry.

    PubMed

    Bianco, Giuliana; Schmitt-Kopplin, Philippe; De Benedetto, Giuseppe; Kettrup, Antonius; Cataldi, Tommaso R I

    2002-09-01

    Glycoalkaloids are naturally occurring nitrogen-containing compounds present in many species of the family Solanaceae, including cultivated and wild potatoes (Solanum spp.), tomatoes (Lycopersicon spp.), etc. These compounds have pharmacological and toxicological effects on humans due to their significant anticholinesterase activity and disruption of cell membranes. Herein is reported the development of a capillary electrophoresis (CE) method using nonaqueous (NA) separation solutions in combination with ion trap mass spectrometry (MS and MS/MS) detection for the identification and quantification of glycoalkaloids and their relative aglycones. A mixture 90:10 v/v of MeCN-MeOH containing 50 mM ammonium acetate and 1.2 M acetic acid (applied voltage of 25.5 kV) was selected as a good compromise for the separation and detection of these compounds. The electrospray MS measurements were carried out in the positive ionization mode using a coaxial sheath liquid, methanol-water (1:1) with 1% of acetic acid at a flow rate of 2.5 microL/min. Under optimized experimental conditions, the predominant ion was the protonated molecular ion ([M+H](+)) of solanidine (m/z = 398), tomatidine (m/z = 416), chaconine (m/z = 852), solanine (m/z = 868), and tomatine (m/z = 1034). MS/MS experiments were carried out systematically by changing the relative collisional energy and monitoring the intensities of the fragment ions that were not high enough to allow better quantification than with the mother ions. The method was used for analyzing glycoalkaloids in potato extracts.

  14. A microfluidic-based enzymatic assay for bioactivity screening combined with capillary liquid chromatography and mass spectrometry.

    PubMed

    de Boer, Arjen R; Bruyneel, Ben; Krabbe, Johannes G; Lingeman, Henk; Niessen, Wilfried M A; Irth, Hubertus

    2005-11-01

    The design and implementation of a continuous-flow microfluidic assay for the screening of (complex) mixtures for bioactive compounds is described. The microfluidic chip featured two microreactors (1.6 and 2.4 microL) in which an enzyme inhibition and a substrate conversion reaction were performed, respectively. Enzyme inhibition was detected by continuously monitoring the products formed in the enzyme-substrate reaction by electrospray ionization mass spectrometry (ESI-MS). In order to enable the screening of mixtures of compounds, the chip-based assay was coupled on-line to capillary reversed-phase high-performance liquid chromatography (HPLC) with the HPLC column being operated either in isocratic or gradient elution mode. In order to improve the detection limits of the current method, sample preconcentration based on a micro on-line solid-phase extraction column was employed. The use of electrospray MS allowed the simultaneous detection of chemical (MS spectra) and biological parameters (enzyme inhibition) of ligands eluting from the HPLC column. The present system was optimized and validated using the protease cathepsin B as enzyme of choice. Inhibition of cathepsin B is detected by monitoring three product traces, obtained by cleavage of the substrate. The two microreactors provided 32 and 36 s reaction time, respectively, which resulted in sufficient assay dynamics to enable the screening of bioactive compounds. The total flow rate was 4 microL min-1, which a 25-fold decrease was compared with a macro-scale system described earlier. Detection limits of 0.17-2.6 micromol L-1 were obtained for the screening of inhibitors, which is comparable to either microtiter plate assays or continuous-flow assays described in the literature.

  15. Integrative metabolomics for characterizing unknown low-abundance metabolites by capillary electrophoresis-mass spectrometry with computer simulations.

    PubMed

    Lee, Richard; Ptolemy, Adam S; Niewczas, Liliana; Britz-McKibbin, Philip

    2007-01-15

    Characterization of unknown low-abundance metabolites in biological samples is one the most significant challenges in metabolomic research. In this report, an integrative strategy based on capillary electrophoresis-electrospray ionization-ion trap mass spectrometry (CE-ESI-ITMS) with computer simulations is examined as a multiplexed approach for studying the selective nutrient uptake behavior of E. coli within a complex broth medium. On-line sample preconcentration with desalting by CE-ESI-ITMS was performed directly without off-line sample pretreatment in order to improve detector sensitivity over 50-fold for cationic metabolites with nanomolar detection limits. The migration behavior of charged metabolites were also modeled in CE as a qualitative tool to support MS characterization based on two fundamental analyte physicochemical properties, namely, absolute mobility (muo) and acid dissociation constant (pKa). Computer simulations using Simul 5.0 were used to better understand the dynamics of analyte electromigration, as well as aiding de novo identification of unknown nutrients. There was excellent agreement between computer-simulated and experimental electropherograms for several classes of cationic metabolites as reflected by their relative migration times with an average error of <2.0%. Our studies revealed differential uptake of specific amino acids and nucleoside nutrients associated with distinct stages of bacterial growth. Herein, we demonstrate that CE can serve as an effective preconcentrator, desalter, and separator prior to ESI-MS, while providing additional qualitative information for unambiguous identification among isobaric and isomeric metabolites. The proposed strategy is particularly relevant for characterizing unknown yet biologically relevant metabolites that are not readily synthesized or commercially available.

  16. Assessing gibberellins oxidase activity by anion exchange/hydrophobic polymer monolithic capillary liquid chromatography-mass spectrometry.

    PubMed

    Chen, Ming-Luan; Su, Xin; Xiong, Wei; Liu, Jiu-Feng; Wu, Yan; Feng, Yu-Qi; Yuan, Bi-Feng

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography--mass spectrometry (cLC-MS) method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20). An anion exchange/hydrophobic poly([2-(methacryloyloxy)ethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate)(META-co-DVB-co-EDMA) monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3) of GAs were in the range of 0.62-0.90 fmol. We determined the kinetic parameters (K m) of recombinant GA3-oxidase in Escherichia coli (E. coli) cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology.

  17. Tapered-Tip Capillary Electrophoresis Nano-Electrospray Ionization Mass Spectrometry for Ultrasensitive Proteomics: the Mouse Cortex

    NASA Astrophysics Data System (ADS)

    Choi, Sam B.; Zamarbide, Marta; Manzini, M. Chiara; Nemes, Peter

    2016-11-01

    Ultrasensitive characterization of the proteome raises the potential to understand how differential gene expression orchestrates cell heterogeneity in the brain. Here, we report a microanalytical capillary electrophoresis nano-flow electrospray ionization (CE-nanoESI) interface for mass spectrometry to enable the measurement of limited amounts of proteins in the mouse cortex. Our design integrates a custom-built CE system to a tapered-tip metal emitter in a co-axial sheath-flow configuration. This interface can be constructed in <15 min using readily available components, facilitating broad adaptation. Tapered-tip CE-nanoESI generates stable electrospray by reproducibly anchoring the Taylor cone, minimizes sample dilution in the ion source, and ensures efficient ion generation by sustaining the cone-jet spraying regime. Parallel reaction monitoring provided a 260-zmol lower limit of detection for angiotensin II (156,000 copies). CE was able to resolve a complex mixture of peptides in 330,000 theoretical plates and identify 15 amol ( 1 pg) of BSA or cytochrome c. Over 30 min of separation, 1 ng protein digest from the mouse cortex yielded 217 nonredundant proteins encompassing a 3-log-order concentration range using a quadrupole time-of-flight mass spectrometer. Identified proteins included many products from genes that are traditionally used to mark oligodendrocytes, astrocytes, and microglia. Finally, key proteins involved in neurodegenerative disorders were detected (e.g., parkinsonism and spastic paraplegia). CE-nanoESI-HRMS delivers sufficient sensitivity to detect proteins in limited amounts of tissues and cell populations to help understand how gene expression differences maintain cell heterogeneity in the brain.

  18. Multiresidue determination of pesticides in malt beverages by capillary gas chromatography with mass spectrometry and selected ion monitoring.

    PubMed

    Wong, Jon W; Webster, Michael G; Bezabeh, Dawit Z; Hengel, Mathew J; Ngim, Kenley K; Krynitsky, Alexander J; Ebeler, Susan E

    2004-10-20

    A method was developed to determine pesticides in malt beverages using solid phase extraction on a polymeric cartridge and sample cleanup with a MgSO4-topped aminopropyl cartridge, followed by capillary gas chromatography with electron impact mass spectrometry in the selected ion monitoring mode [GC-MS(SIM)]. Three GC injections were required to analyze and identify organophosphate, organohalogen, and organonitrogen pesticides. The pesticides were identified by the retention times of peaks of the target ion and qualifier-to-target ion ratios. GC detection limits for most of the pesticides were 5-10 ng/mL, and linearity was determined from 50 to 5000 ng/mL. Fortification studies were performed at 10 ng/mL for three malt beverages that differ in properties such as alcohol content, solids, and appearance. The recoveries from the three malt beverages were greater than 70% for 85 of the 142 pesticides (including isomers) studied. The data showed that the different malt beverage matrixes had no significant effect on the recoveries. This method was then applied to the screening and analysis of malt beverages for pesticides, resulting in the detection of the insectide carbaryl and the fungicide dimethomorph in real samples. The study indicates that pesticide levels in malt beverages are significantly lower than the tolerance levels set by the United States Environmental Protection Agency for malt beverage starting ingredients. The use of the extraction/cleanup procedure and analysis by GC-MS(SIM) proved effective in screening malt beverages for a wide variety of pesticides.

  19. Virtual quantification of metabolites by capillary electrophoresis-electrospray ionization-mass spectrometry: predicting ionization efficiency without chemical standards.

    PubMed

    Chalcraft, Kenneth R; Lee, Richard; Mills, Casandra; Britz-McKibbin, Philip

    2009-04-01

    A major obstacle in metabolomics remains the identification and quantification of a large fraction of unknown metabolites in complex biological samples when purified standards are unavailable. Herein we introduce a multivariate strategy for de novo quantification of cationic/zwitterionic metabolites using capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) based on fundamental molecular, thermodynamic, and electrokinetic properties of an ion. Multivariate calibration was used to derive a quantitative relationship between the measured relative response factor (RRF) of polar metabolites with respect to four physicochemical properties associated with ion evaporation in ESI-MS, namely, molecular volume (MV), octanol-water distribution coefficient (log D), absolute mobility (mu(o)), and effective charge (z(eff)). Our studies revealed that a limited set of intrinsic solute properties can be used to predict the RRF of various classes of metabolites (e.g., amino acids, amines, peptides, acylcarnitines, nucleosides, etc.) with reasonable accuracy and robustness provided that an appropriate training set is validated and ion responses are normalized to an internal standard(s). The applicability of the multivariate model to quantify micromolar levels of metabolites spiked in red blood cell (RBC) lysates was also examined by CE-ESI-MS without significant matrix effects caused by involatile salts and/or major co-ion interferences. This work demonstrates the feasibility for virtual quantification of low-abundance metabolites and their isomers in real-world samples using physicochemical properties estimated by computer modeling, while providing deeper insight into the wide disparity of solute responses in ESI-MS. New strategies for predicting ionization efficiency in silico allow for rapid and semiquantitative analysis of newly discovered biomarkers and/or drug metabolites in metabolomics research when chemical standards do not exist.

  20. 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

    2011-11-07

    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. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  1. Simultaneous determination of six toxic alkaloids in human plasma and urine using capillary zone electrophoresis coupled to time-of-flight mass spectrometry.

    PubMed

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

    2012-10-01

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

  2. Identification of water-soluble polar organics in air and vehicular emitted particulate matter using ultrahigh resolution mass spectrometry and Capillary electrophoresis - mass spectrometry.

    NASA Astrophysics Data System (ADS)

    Schmitt-Kopplin, P.; Yassine, M.; Gebefugi, I.; Hertkorn, N.; Dabek-Zlotorzynska, E.

    2009-04-01

    The effects of aerosols on human health, atmospheric chemistry, and climate are among the central topics in current environmental health research. Detailed and accurate measurements of the chemical composition of air particulate matter (PM) represent a challenging analytical task. Minute sample amounts are usually composed of several main constituents and hundreds of minor and trace constituents. Moreover, the composition of individual particles can be fairly uniform or very different (internally or externally mixed aerosols), depending on their origin and atmospheric aging processes (coagulation, condensation / evaporation, chemical reaction). The aim of the presentation was the characterization of the organic matter (OM) fraction of environmental aerosols which is not accessible by GC-methods, either because of their high molecular weight, their polarity or due to thermal instability. We also describe the main chemical characteristics of complexe oligomeric organic fraction extracted from different aerosols collected in urban and rural area in Germany and Canada. Mass spectrometry (MS) became an essential tool used by many prominent leaders of the biological research community and the importance of MS to the future of biological research is now clearly evident as in the fields of Proteomics and Metabolomics. Especially Fourier Transform Ion Cyclotron Mass Spectrometry (ICR-FT/MS) is an ultrahigh resolution MS that allows new approach in the analysis of complex mixtures. The mass resolution (< 200 ppb) allowed assigning the elemental composition (C, H, O, N, S…) to each of the obtained mass peaks and thus already a description of the mixture in terms of molecular composition. This possibility is used by the authors together with a high resolution separation method of charged compounds: capillary electrophoresis. A CE-ESI-MS method using an ammonium acetate based background electrolyte (pH 4.7) was developed for the determination of isomeric benzoic acids in

  3. A High Voltage Power Supply That Mitigates Current Reversals in Capillary Zone Electrophoresis-Electrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  4. Multidimensional capillary array liquid chromatography and matrix-assisted laser desorption/ionization tandem mass spectrometry for high-throughput proteomic analysis.

    PubMed

    Liu, Chunli; Zhang, Xiangmin

    2007-01-19

    A two-dimensional capillary array liquid chromatography system coupled with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) was developed for high-throughput comprehensive proteomic analysis, in which one strong cation-exchange (SCX) capillary chromatographic column was used as the first separation dimension and 10 parallel reversed-phase liquid chromatographic (RPLC) capillary columns were used as the second separation dimension. A novel multi-channel interface was designed and fabricated for on-line coupling of the SCX to RPLC column array system. Besides the high resolution based on the combination of SCX and RPLC separation, the developed new system provided the most rapid two-dimensional liquid chromatography (2D-LC) separation. Ten three-way micro-splitter valves used as stop-and-flow switches in transferring SCX fractions onto RPLC columns. In addition, the three-way valves also acted as mixing chambers of RPLC effluent with matrix. The system enables on-line mixing of the LC array effluents with matrix solution during the elution and directly depositing the analyte/matrix mixtures on MALDI plates from the tenplexed channels in parallel through an array of capillary tips. With the novel system, thousands of peptides were well separated and deposited on MALDI plates only in 150min for a complex proteome sample. Compared with common 2D-LC system, the parallel 2D-LC system showed about 10-times faster analytical procedure. In combination with a high throughput tandem time of flight mass spectrometry, the system was proven to be very effective for proteome analysis by analyzing a complicated sample, soluble proteins extracted from a liver cancer tissue, in which over 1202 proteins were identified.

  5. Microdetermination of glucose content of plasma and its isotopic enrichment using capillary gas chromatography/ammonia chemical-ionization mass spectrometry.

    PubMed

    Lepetit, N; Rocchiccioli, F

    1989-05-01

    A new sensitive and precise method for the determination of the isotopic enrichment of [6,6-D2]glucose and concentration of glucose in plasma microsamples (20 microL) has been developed. Glucose was extracted from plasma samples by anion-cation column-exchange with absolute ethanol, derivatized as 1,2:3,5-bis(butylboronate)-6-acetyl-alpha-D-glucofuranose, and analysed by capillary gas chromatography/ammonia chemical-ionization mass spectrometry. This method gives a better reproducibility and precision (variation coefficient below 1%) than methods using isobutane chemical ionization. Stable isotopes are being used increasingly to investigate energy metabolism in vivo. Recent work has involved the development of methodologies, especially mass spectrometry, to perform tracer experiments using the stable isotopes 3H, 13C, or 13N(1-4). Chemical-ionization mass spectrometry is extensively used for the analysis of isotopically labelled amino acids. In neonates and children, "true" glucose production can be measured by the continuous infusion of the stable isotopically labelled tracer 6,6-dideutero-glucose (6,6-D2-glucose), and analytical measurement is performed using gas chromatography/electron-ionization mass spectrometry (GC/EIMS). Herein, we present a new, simple and sensitive method for the determination of the isotopic enrichment of [6,6-D2]glucose and measurement of the concentration of glucose in plasma microsamples (20 microL), based on the use of capillary gas-chromatography/ammonia chemical-ionization mass spectrometry of 1,2:3,5-bis(butylboronate)-6-acetyl-alpha-D-glucofuranose.

  6. Automatic sampling and analysis of organics and biomolecules by capillary action-supported contactless atmospheric pressure ionization mass spectrometry.

    PubMed

    Hsieh, Cheng-Huan; Meher, Anil Kumar; Chen, Yu-Chie

    2013-01-01

    Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (∼1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated.

  7. Automatic Sampling and Analysis of Organics and Biomolecules by Capillary Action-Supported Contactless Atmospheric Pressure Ionization Mass Spectrometry

    PubMed Central

    Hsieh, Cheng-Huan; Meher, Anil Kumar; Chen, Yu-Chie

    2013-01-01

    Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (∼1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated. PMID:23762484

  8. Sensitive determination of a glyoxal-DNA adduct biomarker candidate by column switching capillary liquid chromatography electrospray ionization mass spectrometry.

    PubMed

    Olsen, Raymond; Ovrebø, Steinar; Thorud, Syvert; Lundanes, Elsa; Thomassen, Yngvar; Greibrokk, Tyge; Molander, Paal

    2008-06-01

    A method based on column switching packed capillary liquid chromatography electrospray mass spectrometry has been developed for the determination of the adduct glyoxal-deoxyguanosine, a biomarker candidate for the assessment of glyoxal exposure, in DNA hydrolysate solutions. Microgram amounts of DNA were isolated and enzymatically hydrolyzed to deoxyribonucleosides, prior to ultrafiltration and subsequent dilution to a sample solution consisting of water-acetonitrile-formic acid (98 : 2 : 0.2, v/v). The sample solution was loaded onto a 1 mm I.D. x 5 mm Hypercarb (5 mum) porous graphitic carbon trap column for analyte enrichment using an injection volume of 200 mul, and was subsequently back-flushed onto a 0.30 mm I.D. x 150 mm Lichrospher diol (5 mum) analytical column. The samples were loaded with a flow rate of 40 mul min(-1) and glyoxal-deoxyguanosine was desorbed from the trap column and eluted with an isocratic mobile phase consisting of water-acetonitrile-formic acid (50 : 50 : 0.2, v/v) at a flow rate of 5 mul min(-1). Mass spectrometric determination of glyoxal-deoxyguanosine was obtained by multiple reaction monitoring of the transition [M + H](+)m/z 326 --> m/z 210. The method was evaluated over the concentration range 0.25-50 ng ml(-1) of glyoxal-deoxyguanosine in the hydrolysate of 5 mug DNA. The method was linear with a correlation coefficient of 0.9998 in this range. The within-day (n = 6) and between-day (n = 6) precisions were determined as 1.2-11% and 1.4-11% RSD, respectively, and the recovery was close to 100%. The mass limit of detection was 15 pg, corresponding to a concentration limit of detection of 75 fg mul(-1) DNA hydrolysate solution, corresponding to 48 adducts per 10(6) normal nucleosides. The method was applied for the determination of glyoxal-deoxyguanosine in DNA hydrolysate solutions of calf thymus DNA and cell cultures after reaction or incubation with glyoxal.

  9. Hyaluronidase reaction kinetics evaluated by capillary electrophoresis with UV and high-resolution mass spectrometry (HRMS) detection.

    PubMed

    Fayad, Syntia; Nehmé, Reine; Langmajerová, Monika; Ayela, Benjamin; Colas, Cyril; Maunit, Benoit; Jacquinet, Jean-Claude; Vibert, Aude; Lopin-Bon, Chrystel; Zdeněk, Glatz; Morin, Philippe

    2017-01-25

    The biology of hyaluronidase activity on age related turnover of the hyaluronic acid (HA) in skin dermis and epidermis has not been established. Elucidation of this phenomenon enables discovery of novel compounds for skin health. As a simple and green technique, capillary electrophoresis (CE) was used for the first time for the determination of the kinetic constants (Km, Vmax and IC50) of the enzymatic degradation of HA. Reaction products were identified using CE/high-resolution mass spectrometry (HRMS) after appropriate optimization. Best results in terms of signal sensitivity were obtained using 10 mM ammonium acetate (pH 9.0) BGE, a sheath liquid composed of methanol-water (80:20, v/v) with 0.02% (v/v) formic acid at 10 μL min(-1) and an ESI voltage at -4 kV. Km and Vmax were determined (n = 3) using CE/UV at 200 nm as 0.24 ± 0.02 mg mL(-1) and 150.4 ± 0.1 nM s(-1), respectively. They were also successfully obtained by CE/HRMS (n = 3) with Km of 0.49 ± 0.02 mg mL(-1) and Vmax of 155.7 ± 0.2 nM s(-1). IC50 of a standard natural inhibitor, epigallocatechin gallate, was also determined by CE-UV/HRMS. Kinetic constant values obtained by CE compared well with literature which validated the developed CE-based assay. In addition, the activity of homemade tetrasaccharides of biotinylated chondroitin sulfate CS-A or CS-C (4- or 6- sulfated in a homogeneous or heterogeneous way) on the hydrolysis reaction of hyaluronidase was evaluated. Hyaluronidase was mostly dose-dependently inhibited by CS-A tetrasaccharides sulfated in a homogeneous way. Two trisaccharides from truncated linkage region of proteoglycans were also tested as inhibitors or activators. CE-based assay showed that even a small modification of one hydroxyl group changes the influence on hyaluronidase activity. CE-based assay can be used for the screening of natural and synthetic inhibitors of hyaluronidase activity for cosmetic and therapeutic applications.

  10. The use of selective adsorbents in capillary electrophoresis-mass spectrometry for analyte preconcentration and microreactions: a powerful three-dimensional tool for multiple chemical and biological applications.

    PubMed

    Guzman, N A; Stubbs, R J

    2001-10-01

    Much attention has recently been directed to the development and application of online sample preconcentration and microreactions in capillary electrophoresis using selective adsorbents based on chemical or biological specificity. The basic principle involves two interacting chemical or biological systems with high selectivity and affinity for each other. These molecular interactions in nature usually involve noncovalent and reversible chemical processes. Properly bound to a solid support, an "affinity ligand" can selectively adsorb a "target analyte" found in a simple or complex mixture at a wide range of concentrations. As a result, the isolated analyte is enriched and highly purified. When this affinity technique, allowing noncovalent chemical interactions and biochemical reactions to occur, is coupled on-line to high-resolution capillary electrophoresis and mass spectrometry, a powerful tool of chemical and biological information is created. This paper describes the concept of biological recognition and affinity interaction on-line with high-resolution separation, the fabrication of an "analyte concentrator-microreactor", optimization conditions of adsorption and desorption, the coupling to mass spectrometry, and various applications of clinical and pharmaceutical interest.

  11. Near infrared spectroscopy compared to liquid chromatography coupled to mass spectrometry and capillary electrophoresis as a detection tool for peptide reaction monitoring.

    PubMed

    Petter, Christine H; Heigl, Nico; Bachmann, Stefan; Huck-Pezzei, Verena A C; Najam-Ul-Haq, Muhammad; Bakry, Rania; Bernkop-Schnürch, Andreas; Bonn, Günther K; Huck, Christian W

    2008-05-01

    Peptide interaction is normally monitored by liquid chromatography (LC), liquid chromatography coupled to mass spectrometry (LC-MS), mass spectrometric (MS) methods such as MALDI-TOF/MS or capillary electrophoresis (CE). These analytical techniques need to apply either high pressure or high voltages, which can cause cleavage of newly formed bondages. Therefore, near infrared reflectance spectroscopy (NIRS) is presented as a rapid alternative to monitor the interaction of glutathione and oxytocin, simulating physiological conditions. Thereby, glutathione can act as a nucleophile with oxytocin forming four new conjugates via a disulphide bondage. Liquid chromatography coupled to UV (LC-UV) and mass spectrometry via an electrospray ionisation interface (LC-ESI-MS) resulted in a 82% and a 78% degradation of oxytocin at pH 3 and a 5% and a 7% degradation at pH 6.5. Capillary electrophoresis employing UV-detection (CE-UV) showed a 44% degradation of oxytocin. LC and CE in addition to the NIRS are found to be authentic tools for quantitative analysis. Nevertheless, NIRS proved to be highly suitable for the detection of newly formed conjugates after separating them on a thin layer chromatography (TLC) plate. The recorded fingerprint in the near infrared region allows for a selective distinct qualitative identification of conjugates without the need for expensive instrumentation such as quadrupole or MALDI-TOF mass spectrometers. The performance of the established NIRS method is compared to LC and CE; its advantages are discussed in detail.

  12. Direct comparison of capillary electrophoresis and capillary liquid chromatography hyphenated to collision-cell inductively coupled plasma mass spectrometry for the investigation of Cd-, Cu- and Zn-containing metalloproteins.

    PubMed

    Montes-Bayon, Maria; Pröfrock, Daniel; Sanz-Medel, Alfredo; Prange, Andreas

    2006-05-05

    Capillary liquid chromatography (cLC) and capillary electrophoresis (CE) have been critically compared for the separation of metalloproteins when using collision-cell inductively coupled plasma mass spectrometry (ICP-CC-MS) as detection system. For cLC separation, the selected column was a C8 (0.3 mm I.D.) and the separation conditions involved a gradient up to 80% methanol in 10mM ammonium acetate buffer (pH 7.4). The low flow rate used (3 microL min(-1)) permitted the utilization of a high methanol content maintaining the sensitivity along the whole chromatographic run. For this purpose, a new low-flow interface has been developed based on a total consumption nebulizer. Similarly, CE has been studied as separation technique using a 75 microm I.D. fused silica capillary and a running buffer of 20 mM Tris-HNO3 (pH 7.4) and working at 30 kV. Metallothionein (mixture of MT-I and -II) and superoxide dismutase (SOD) have been used as protein models in order to evaluate the separation/detection capabilities using the same injection volumes in both systems (20 nL). For both hybrid systems, separation parameters such as retention factor, numbers of theoretical plates, tailing factor and resolution have been critically compared. Also, the analytical performance characteristics of both hybrid systems have been evaluated and tested by analyzing the Cu-, Zn-species present in red blood cell extracts in order to explore more adequate separation methodology for the analysis of metalloproteins in complex matrices.

  13. Capillary microextraction combined with fluorinating assisted electrothermal vaporization inductively coupled plasma optical emission spectrometry for the determination of trace lanthanum, europium, dysprosium and yttrium in human hair.

    PubMed

    Wu, Shaowei; Hu, Chengguo; He, Man; Chen, Beibei; Hu, Bin

    2013-10-15

    In this work, a congo red modified single wall carbon nanotubes (CR-SWCNTs) coated fused-silica capillary was prepared and used for capillary microextraction (CME) of trace amounts of lanthanum (La), europium (Eu), dysprosium (Dy) and yttrium (Y) in human hair followed by fluorinating assisted electrothermal vaporization-inductively coupled plasma-optical emission spectrometry (FETV-ICP-OES) determination. The adsorption properties and stability of the prepared CR-SWCNTs coated capillary along with the various factors affecting the separation/preconcentration of La, Eu, Dy and Y by CME were investigated in detail. Under the optimized conditions, with a consumption of 2 mL sample solution, a theoretical enrichment factor of 50 and a detection limit (3σ) of 0.12 ng mL(-1) for La, 0.03 ng mL(-1) for Eu, 0.11 ng mL(-1) for Dy and 0.03 ng mL(-1) for Y were obtained, respectively. The preparation reproducibility of the CR-SWCNTs coated capillary was investigated and the relative standard deviations (RSDs) were ranging from 4.1% (Eu) to 4.4% (La) (CLa, Dy=1.4 ng mL(-1); CY, Eu=0.25 ng mL(-1), n=7) in one batch, and from 5.7% (Eu) to 6.1% (Y) (CLa, Dy=1.4 ng mL(-1); CY, Eu=0.25 ng mL(-1), n=5) among different batches. The proposed method was applied to the analysis of real-world human hair sample and the recoveries for the spiked sample were in the range of 93-105%. The method was also applied to the determination of La, Eu, Dy and Y in Certified Reference Material of GBW07601 human hair, and the determined values were in good agreement with the certified values.

  14. Capillary Hemangioma

    MedlinePlus

    ... Why do capillary hemangiomas on the eyelids cause vision problems? Capillary Hemangiomas of the eyelid can cause ... a capillary hemangioma in the eye socket cause vision problems? A capillary hemangioma in the eye socket ( ...

  15. Capillary electrophoresis and capillary electrophoresis-ion trap multiple-stage mass spectrometry for the differentiation and identification of oxycodone and its major metabolites in human urine.

    PubMed

    Wey, Anita B; Thormann, Wolfgang

    2002-04-25

    Oxycodone (OCOD) and its metabolites, including oxymorphone (OMOR), noroxycodone (NOCOD) and noroxymorphone (NOMOR), are opioids that carry an OH group at position 14. Using capillary electrophoresis (CE) with a binary phosphate buffer containing 60% ethylene glycol (pH 7.9), the migration order of OCOD and OMOR with respect to their N-demethylated analogs was found to be reversed compared to that observed for codeine, dihydrocodeine, morphine and dihydromorphine, compounds that do not have an OH group at position 14. OCOD and structurally related compounds can also be distinguished from these opioids by their absorbance spectra at low wavelengths and via a characteristic neutral H2O loss at the MS2 level. Using the binary phosphate buffer, CE with UV detection is shown to be capable of monitoring OCOD, NOCOD, OMOR (after hydrolysis only) and NOMOR (after hydrolysis and in patient urine only) in alkaline liquid-liquid extracts of urines that were collected after ingestion of 10 mg OCOD hydrochloride and in a patient urine collected at steady state (80 mg OCOD hydrochloride daily). Using an aqueous pH 9 ammonium acetate buffer, these results were confirmed by CE-MS3. Based on CE-MS, MS2 and MS3 data, the absorbance spectra measured across the CE peaks and the relative position within the electropherogram, two peaks monitored in the UV absorbance electropherograms could be assigned to the two keto-reduced metabolites 6oxycodol (60COL) and nor6oxycodol, for which no standards were available. Comparison of data obtained with urines pretreated with two different enzyme products (beta-glucuronidase and beta-glucuronidase/arylsulfatase) suggest that OCOD, NOCOD and 6OCOL are mainly glucuronidated, whereas OMOR mainly forms other conjugates. Furthermore, in a first attempt to directly measure conjugates of the compounds of interest, solid-phase extracts were analyzed by CE-MS4, which revealed the presence of the acyl glucuronides of 6OCOL and OMOR and an unidentified OMOR

  16. Proteome Analyses Using Accurate Mass and Elution Time Peptide Tags with Capillary LC Time-of-Flight Mass Spectrometry

    SciTech Connect

    Strittmatter, Eric F.; Ferguson, Patrick L.; Tang, Keqi; Smith, Richard D.

    2003-09-01

    We describe the application of capillary liquid chromatography (LC) time-of-flight (TOF) mass spectrometric instrumentation for the rapid characterization of microbial proteomes. Previously (Lipton et al. Proc. Natl Acad. Sci. USA, 99, 2002, 11049) the peptides from a series of growth conditions of Deinococcus radiodurans have been characterized using capillary LC MS/MS and accurate mass measurements which are logged in an accurate mass and time (AMT) tag database. Using this AMT tag database, detected peptides can be assigned using measurements obtained on a TOF due to the additional use of elution time data as a constraint. When peptide matches are obtained using AMT tags (i.e. using both constraints) unique matches of a mass spectral peak occurs 88% of the time. Not only are AMT tag matches unique in most cases, the coverage of the proteome is high; {approx}3500 unique peptide AMT tags are found on average per capillary LC run. From the results of the AMT tag database search, {approx}900 ORFs detected using LC-TOFMS, with {approx}500 ORFs covered by at least two AMT tags. These results indicate that AMT databases searches with modest mass and elution time criteria can provide proteomic information for approximately one thousand proteins in a single run of <3 hours. The advantage of this method over using MS/MS based techniques is the large number of identifications that occur in a single experiment as well as the basis for improved quantitation. For MS/MS experiments, the number of peptide identifications is severely restricted because of the time required to dissociate the peptides individually. These results demonstrate the utility of the AMT tag approach using capillary LC-TOF MS instruments, and also show that AMT tags developed using other instrumentation can be effectively utilized.

  17. Analysis of low molecular weight acids by monolithic immobilized pH gradient-based capillary isoelectric focusing coupled with mass spectrometry.

    PubMed

    Wang, Tingting; Fekete, Agnes; Gaspar, Andras; Ma, Junfeng; Liang, Zhen; Yuan, Huiming; Zhang, Lihua; Schmitt-Kopplin, Philippe; Zhang, Yukui

    2011-02-01

    A novel method for the separation and detection of low molecular weight (LMW) acids was developed using monolithic immobilized pH gradient-based capillary isoelectric focusing coupled with mass spectrometry. Two main parameters, focusing conditions and delivery buffer conditions, which might affect separation efficiency, were optimized with the focusing time of 7 min at 350 V/cm and the delivery buffer of 50% (v/v) acetonitrile in 10 mmol/L ammonium formate (pH 3.0). Under these conditions, the linear correlation between the volume of delivery solvent and the pK(a) of the model components was observed. In addition, the separation mechanism of LMW acids was proposed as well. We suppose that this method may provide a useful tool for the characterization of LMW components (e.g. natural organic matter of different origins). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Determination of chromium (III) in natural water samples utilizing capillary micro-extraction on nanometre zirconium phosphate coating coupled to electrothermal atomic absorbance spectrometry.

    PubMed

    Bai, Xiaohong; Fan, Zhefeng

    2009-02-01

    A simple and sensitive method for the separation of Cr(III) in natural water was developed. The novel method was targeted on extraction of Cr(III) by using a nanometre-scale zirconium phosphate coated capillary tube, and determined by electrothermal atomic absorption spectrometry (ETAAS). The variables influencing the micro-extraction of Cr(III) including pH, sample volume, sample flow rate, eluent volume and eluent flow rate were investigated. Under the optimized conditions, the detection limit (3s) was 0.042 ng mL(-1), and the relative standard deviation (RSD) was 1.5% (c=10 ng mL(-1), n=7). The proposed method was applied to determination of Cr(III) in natural waters.

  19. New pseudopeptidic cross-linker containing urea bonds: study of its degradation routes in aqueous media using capillary electrophoresis-mass spectrometry.

    PubMed

    Pérez, Paloma; Simó, Carolina; Neusüss, Christian; Pelzing, Matthias; San Roman, Julio; Cifuentes, Alejandro; Gallardo, Alberto

    2006-03-01

    An accelerated degradation study has been performed on TLT, a pseudopeptide that includes esterified tyrosine and lysine linked by urea bonds, as well as on their derivatives, i.e., a dimethacrylic cross-linker (DMTLT) and a poly(dimethylacrylamide) cross-linked with DMTLT. The monitoring and analytical characterization has been carried out by capillary electrophoresis-mass spectrometry (CE-MS), using ion trap and time-of-flight MS analyzers. Several degradative species have been identified, and a kinetic analysis of the variation of their concentration with time has been obtained. During the initial stages of degradation, there is a competition between hydrolysis of the ester groups and cyclization by nucleophilic attack of the NHs of the urea groups to the carbonyl ester group. At higher degradation time (weeks or months), evidences of backbone breakdown, including urea hydrolysis, have been found.

  20. Analysis of hop acids and their oxidized derivatives and iso-alpha-acids in beer by capillary electrophoresis-electrospray ionization mass spectrometry.

    PubMed

    García-Villalba, Rocío; Cortacero-Ramírez, Sonia; Segura-Carretero, Antonio; Martín-Lagos Contreras, José Antonio; Fernández-Gutiérrez, Alberto

    2006-07-26

    This study investigates the applicability of on-line coupling of capillary electrophoresis with electrospray ionization tandem mass spectrometry (CZE-ESI-MS) for the separation and characterization of alpha- and beta-acids and oxidized hop acids from crude extracts of different hop varieties. CZE-ESI-MS with negative-ion electrospray ionization proved to be a suitable technique for the determination of these types of natural compounds and their oxidized derivatives. The CZE parameters (pH, concentration, and buffer type) and ESI-MS parameters (nature and flow rate of the sheath liquid, nebulizer pressure, drying gas flow rate, temperature, and compound stability) were optimized. The optimized method provides the potential for a fast qualitative determination of hop acids and their oxidation compounds. The method was also applied to the determination of iso-alpha-acids in beer.

  1. Increasing conclusiveness of clinical breath analysis by improved baseline correction of multi capillary column - ion mobility spectrometry (MCC-IMS) data.

    PubMed

    Szymańska, Ewa; Tinnevelt, Gerjen H; Brodrick, Emma; Williams, Mark; Davies, Antony N; van Manen, Henk-Jan; Buydens, Lutgarde M C

    2016-08-05

    Current challenges of clinical breath analysis include large data size and non-clinically relevant variations observed in exhaled breath measurements, which should be urgently addressed with competent scientific data tools. In this study, three different baseline correction methods are evaluated within a previously developed data size reduction strategy for multi capillary column - ion mobility spectrometry (MCC-IMS) datasets. Introduced for the first time in breath data analysis, the Top-hat method is presented as the optimum baseline correction method. A refined data size reduction strategy is employed in the analysis of a large breathomic dataset on a healthy and respiratory disease population. New insights into MCC-IMS spectra differences associated with respiratory diseases are provided, demonstrating the additional value of the refined data analysis strategy in clinical breath analysis.

  2. Determination of immunoreactive gonadotropin-releasing hormone in serum and urine by on-line immunoaffinity capillary electrophoresis coupled to mass spectrometry.

    PubMed

    Guzman, N A

    2000-12-01

    The need for urgent diagnoses has propelled the development of automated analyses that can be performed in a short time at reasonable cost. One such method is immunoaffinity capillary electrophoresis. This emerging hybrid technology employs two powerful techniques coupled on-line for the direct and rapid determination of analytes present in biological fluids. The first technique, immunoaffinity, is used for the selective extraction of a molecule present in a complex matrix, utilizing a microscale-format chamber affinity device. An analyte (affinity target) present in serum or urine is captured by an immobilized molecular recognition antibody molecule (affinity ligand) bound to a solid support constituent (glass beads or an appropriate porous structure) of a microchamber affinity device. The second technique, capillary electrophoresis, is used for the high-resolution analytical separation of the purified and concentrated affinity target material after elution from the microchamber affinity device. In this work, immunoaffinity capillary electrophoresis was developed for the identification and characterization of a single constituent of a complex matrix. Immunoreactive gonadotropin-releasing hormone was determined in serum and urine specimens derived from a normal individual and from a patient suffering from benign prostatic hyperplasia. Furthermore, the on-line immuno-separation system was coupled in tandem to mass spectrometry to obtain molecular mass information of the affinity isolated and CE separated neuropeptide. This hybrid immuno-analytical technology is simple, rapid, selective and sensitive. In addition, an attempt was also made to characterize other urinary constituents by CE-MS that may lead to marker activity in the urine of the diseased subject. The hyphenation of analytical techniques has proved valuable in enhancing their individual features. The future of bioanalysis using miniaturized affinity systems is discussed in this paper.

  3. Highly sensitive profiling assay of acidic plant hormones using a novel mass probe by capillary electrophoresis-time of flight-mass spectrometry.

    PubMed

    Chen, Ming-Luan; Huang, Yun-Qing; Liu, Jia-Qi; Yuan, Bi-Feng; Feng, Yu-Qi

    2011-04-15

    Plant hormones play crucial roles in plant growth and development. However, up to date, identification and quantification of acidic plant hormones with trace amount in complicated plant matrix is still a challenge. In current study, we developed a high sensitive assay for the determination of acidic plant hormones in rice by combining capillary electrophoresis and electrospray ionization-time of flight-mass spectrometry (CE-ESI-TOF-MS). To improve the detection sensitivity of acidic plant hormones, 3-bromoactonyltrimethylammonium bromide (BTA) was synthesized as a new mass probe, which can react efficiently with acidic plant hormones in acetonitrile containing triethylamine (TEA). The positively charged BTA-derivatives were separated by CE using amino-coated capillary, which provided a reversed electroosmotic flow (EOF) at low pH, as well as reduced the adsorption of BTA-derivatives on the inner wall of capillary. Using the CE-ESI-TOF-MS method developed in current study, 15 acidic plant hormones, including 10 gibberellins (GAs), were identified and quantified with good linearities from 1.3 to 850 ng/mL with linear coefficient R(2) values of >0.99. The limits of detection (LODs) were in the range of 0.34-4.59 ng/mL. Recoveries of compounds from spiked beverage samples ranged from 84.6 to 112.2%. And a good reproducibility was obtained by evaluating the intra and inter-day precisions with relative standard deviations (RSDs) less than 6.7 and 9.9%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Automated coupling of capillary-HPLC to matrix-assisted laser desorption/ionization mass spectrometry for the analysis of small molecules utilizing a reactive matrix.

    PubMed

    Brombacher, Stephan; Owen, Stacey J; Volmer, Dietrich A

    2003-07-01

    This study describes the application of a novel, reactive matrix for the mass spectral analysis of steroids by capillary-high performance liquid chromatography (capillary-HPLC) coupled to matrix-assisted laser desorption/ionization (MALDI). The mass spectral analysis of steroids was accomplished after fully automated peak deposition of chromatographic peaks onto MALDI targets. The seven corticosteroids used as test compounds were: triamcinolone, prednisone, cortisone, fludrocortisone, dexamethasone, deoxycorticosterone, and budesonide. They were separated using a PepMap C(18) (3 microm particle size, 100 A pore width) column at five different concentration levels of 25, 15, 7.5, 2.5 and 1 ng/microL, and the peaks were detected at a wavelength of 237 nm. The column effluent was mixed with 2,4-dinitrophenylhydrazine (DNPH) directly following the UV detector. The chromatographic peaks were then deposited onto the MALDI target with a robotic micro-fraction collector triggered by the UV detector signals. A special hydrophobic surface coating allowed the deposition of up to 4 microL (up to 90 % of the chromatographic peak volume) onto one sample spot. The compounds were then identified by MALDI mass spectrometry. Depending on the nature of the analyte, radical cations ([M](+.)) and sodium adduct ions ([M+Na](+)) of the steroids as well as protonated steroid-dinitrophenylhydrazone derivatives ([M(D)+H](+)) were detected in positive ion mode. The detection limits were between 0.5 and 15 ng injected with capillary-HPLC-MALDI-TOF-MS and between 0.3 and 3 ng on target with MALDI-TOF when deposited manually.

  5. Development of a capillary high performance liquid chromatography-ion trap-mass spectrometry method for the determination of VLIVP antihypertensive peptide in soybean crops.

    PubMed

    Puchalska, Patrycja; García, M Concepción; Marina, M Luisa

    2014-04-18

    Soybean peptide VLIVP presents a very high antihypertensive activity (IC50 value 1.69μM), even higher than extensively studied IPP and VPP peptides from milk. Nevertheless, no much attention has been paid to this peptide and there is no method enabling its determination in soybeans. The aim of this work was the development of an analytical methodology for this purpose. A methodology consisting of the extraction of soybean proteins, their digestion with Protease P enzyme, their chromatographic separation using capillary-HPLC, and IT-MS detection was optimized. Protein extraction was performed by the use of high intensity focused ultrasounds to obtain a reduced extraction time. Optimization of chromatographic and mass spectrometry parameters enabled the separation of VLIVP peptide within just 7min and its sensitive detection. The analytical characteristics of the capillary-HPLC-IT-MS method were evaluated through the study of linearity, LOD, LOQ, study of the presence of matrix interferences, precision, and recovery. The method enabled to detect as low as 3.6ng of peptide and to determine as low as 12ng of peptide in 1g of soybean (as dry basis). Finally, the developed method was applied to the determination of the antihypertensive peptide VLIVP in different soybean varieties. The results showed the highest yield of VLIVP peptide in variety Mazowiecka II from Poland. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Enantioselective column coupled electrophoresis employing large bore capillaries hyphenated with tandem mass spectrometry for ultra-trace determination of chiral compounds in complex real samples.

    PubMed

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

    2015-12-01

    A new multidimensional analytical approach for the ultra-trace determination of target chiral compounds in unpretreated complex real samples was developed in this work. The proposed analytical system provided high orthogonality due to on-line combination of three different methods (separation mechanisms), i.e. (1) isotachophoresis (ITP), (2) chiral capillary zone electrophoresis (chiral CZE), and (3) triple quadrupole mass spectrometry (QqQ MS). The ITP step, performed in a large bore capillary (800 μm), was utilized for the effective sample pretreatment (preconcentration and matrix clean-up) in a large injection volume (1-10 μL) enabling to obtain as low as ca. 80 pg/mL limits of detection for the target enantiomers in urine matrices. In the chiral CZE step, the different chiral selectors (neutral, ionizable, and permanently charged cyclodextrins) and buffer systems were tested in terms of enantioselectivity and influence on the MS detection response. The performance parameters of the optimized ITP - chiral CZE-QqQ MS method were evaluated according to the FDA guidance for bioanalytical method validation. Successful validation and application (enantioselective monitoring of renally eliminated pheniramine and its metabolite in human urine) highlighted great potential of this chiral approach in advanced enantioselective biomedical applications.

  7. On-line capillary isoelectric focusing hyphenated to native electrospray ionization mass spectrometry for the characterization of interferon-γ and variants.

    PubMed

    Przybylski, Cédric; Mokaddem, Meriem; Prull-Janssen, Mehdi; Saesen, Els; Lortat-Jacob, Hugues; Gonnet, Florence; Varenne, Anne; Daniel, Régis

    2015-01-21

    The on-line hyphenation of Capillary IsoElectric Focusing (CIEF) with ElectroSpray Ionization Mass Spectrometry (ESI/MS) has been carried out in a non-denaturing detection mode at the CIEF-MS interface. This CIEF-MS coupling methodology relied on the use of 40% glycerol-water medium as anti-convective agent in the CE capillary and the addition of 10 mM ammonium acetate buffer, pH 5, as a volatile aqueous sheath liquid. These CIEF-MS coupling conditions allowed the characterization of the highly basic cytokine human interferon-gamma (IFN-γ) and its detection as a non-covalent homodimer (33,814.3 g mol(-1)) corresponding to the active form of this immune-regulatory protein. An experimental pI value of 9.95 was determined for the human IFN-γ homodimer in these conditions. The CIEF-MS analysis of several variants bearing punctual or deletion mutations within the two D1 and D2 basic clusters at the C-terminal end of IFN-γ revealed the different contribution of these domains to the charge properties of this heparan sulfate-binding protein.

  8. Enhancing capillary liquid chromatography/tandem mass spectrometry of biogenic amines by pre-column derivatization with 7-fluoro-4-nitrobenzoxadiazole.

    PubMed

    Song, Yaru; Quan, Zhe; Evans, Joseph L; Byrd, Edward A; Liu, Yi-Ming

    2004-01-01

    This paper describes a capillary liquid chromatography/tandem mass spectrometry (LC/MS/MS) determination of biogenic amines enhanced by pre-column derivatization with 7-fluoro-4-nitrobenzoxadiazole (NBD-F). Biogenic amines including tryptamine, N-methylsalsolinol, histamine, and agmatine were studied. The biogenic NBD-amine derivatives could be quantitatively enriched in-line on 20 x 0.25 mm capillary columns packed in-house with 5 microm C(8) silica particles. In an electrospray ionization (ESI) source these derivatives were ionized effectively, and collision-induced dissociation (CID) produced predominant characteristic ions allowing sensitive MS/MS detection. Agmatine, a potential neurotransmitter/modulator, was taken as a reference compound to study the analytical figures of merit of the procedure. The detection limit of agmatine was estimated to be 0.6 ng/mL (signal-to-noise (S/N) = 3). A linear calibration curve in the range 15-1000 ng/mL agmatine with an r value of 0.9997 was obtained. Tissue samples of rat brain, stomach, and intestine were analyzed. Minimum sample pre-treatment was needed. Each analysis was accomplished within ca. 12 min. The concentration of agmatine was found to be 0.246, 3.31, and 0.058 microg/g wet tissue in the brain, stomach, and intestine, respectively.

  9. Direct quantification of chemical warfare agents and related compounds at low ppt levels: comparing active capillary dielectric barrier discharge plasma ionization and secondary electrospray ionization mass spectrometry.

    PubMed

    Wolf, Jan-Christoph; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2015-01-06

    A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of 13 chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity. The investigated compounds include an intact chemical warfare agent and structurally related molecules, hydrolysis products and/or precursors of highly toxic nerve agents (G-series, V-series, and "new" nerve agents), and blistering and incapacitating warfare agents. Well-defined analyte gas phase concentrations were generated by a pressure-assisted nanospray with consecutive thermal evaporation and dilution. Identification was achieved by selected reaction monitoring (SRM). The most abundant fragment ion intensity of each compound was used for quantification. For DBDI and SESI, absolute gas phase detection limits in the low ppt range (in MS/MS mode) were achieved for all compounds investigated. Although the sensitivity of both methods was comparable, the active capillary DBDI sensitivity was found to be dependent on the applied AC voltage, thus enabling direct tuning of the sensitivity and the in-source fragmentation, which may become a key feature in terms of field applicability. Our findings underline the applicability of DBDI and SESI for the direct, sensitive detection and quantification of several CWA types and their degradation products. Furthermore, they suggest the use of DBDI in combination with hand-held instruments for CWAs on-site monitoring.

  10. Analysis of N-acylhomoserine lactones after alkaline hydrolysis and anion-exchange solid-phase extraction by capillary zone electrophoresis-mass spectrometry.

    PubMed

    Frommberger, Moritz; Hertkorn, Norbert; Englmann, Matthias; Jakoby, Sarah; Hartmann, Anton; Kettrup, Antonius; Schmitt-Kopplin, Philippe

    2005-04-01

    A quantitative, specific, and sensitive method for the determination of N-acylhomoserine lactones (HSLs - a group of bacterial semiochemicals) in the form of their hydrolysis products (N-acylhomoserines, HSs) is presented. Real samples were analyzed by capillary zone electrophoresis-mass spectrometry (CZE-MS) after alkaline lactonolysis and extraction by mixed-mode anion-exchange solid-phase extraction. The presented cleanup significantly speeds up the HSL extraction procedure, strongly reduces sample consumption, and is more selective compared to the commonly used liquid/liquid extraction. Completeness of the hydrolysis reaction was examined by nuclear magnetic resonance spectroscopy. This CZE-MS method complements recently published capillary separation techniques (nano liquid chromatography-MS, partial-filling micellar electrokinetic chromatography-MS, gas chromatography-MS) and provides a possibility to differentiate quantitatively between the homoserines (as naturally occurring degradation products) besides the intact homoserine lactones. The method was found to be quantitative down to a concentration of 0.05 microg/mL (limit of quantification), while the limit of detection was determined with 0.01 microg/mL - sufficient for the analysis of culture supernatants.

  11. Anionic metabolite profiling by capillary electrophoresis-mass spectrometry using a noncovalent polymeric coating. Orange juice and wine as case studies.

    PubMed

    Acunha, Tanize; Simó, Carolina; Ibáñez, Clara; Gallardo, Alberto; Cifuentes, Alejandro

    2016-01-08

    In several metabolomic studies, it has already been demonstrated that capillary electrophoresis hyphenated to mass spectrometry (CE-MS) can detect an important group of highly polar and ionized metabolites that are overseen by techniques such as NMR, LC-MS and GC-MS, providing complementary information. In this work, we present a strategy for anionic metabolite profiling by CE-MS using a cationic capillary coating. The polymer, abbreviated as PTH, is composed of a poly-(N,N,N',N'-tetraethyldiethylenetriamine, N-(2-hydroxypropyl) methacrylamide, TEDETAMA-co-HPMA (50:50) copolymer. A CE-MS method based on PTH-coating was optimized for the analysis of a group of 16 standard anionic metabolites. Separation was achieved within 12min, with high separation efficiency (up to 92,000 theoretical plates per meter), and good repeatability, namely, relative standard deviation values for migration times and peak areas were below 0.2 and 2.1%, respectively. The optimized method allowed the detection of 87 metabolites in orange juice and 142 metabolites in red wine, demonstrating the good possibilities of this strategy for metabolomic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. In Situ Microprobe Single-Cell Capillary Electrophoresis Mass Spectrometry: Metabolic Reorganization in Single Differentiating Cells in the Live Vertebrate (Xenopus laevis) Embryo.

    PubMed

    Onjiko, Rosemary M; Portero, Erika P; Moody, Sally A; Nemes, Peter

    2017-07-05

    Knowledge of single-cell metabolism would provide a powerful look into cell activity changes as cells differentiate to all the tissues of the vertebrate embryo. However, single-cell mass spectrometry technologies have not yet been made compatible with complex three-dimensional changes and rapidly decreasing cell sizes during early development of the embryo. Here, we bridge this technological gap by integrating capillary microsampling, microscale metabolite extraction, and capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS) to enable direct metabolic analysis of identified cells in the live frog embryo (Xenopus laevis). Microprobe CE-ESI-MS of <0.02% of the single-cell content allowed us to detect ∼230 different molecular features (positive ion mode), including 70 known metabolites, in single dorsal and ventral cells in 8-to-32-cell embryos. Relative quantification followed by multivariate and statistical analysis of the data found that microsampling enhanced detection sensitivity compared to whole-cell dissection by minimizing chemical interferences and ion suppression effects from the culture media. In addition, higher glutathione/oxidized glutathione ratios suggested that microprobed cells exhibited significantly lower oxidative stress than those dissected from the embryo. Fast (5 s/cell) and scalable microsampling with minimal damage to cells in the 8-cell embryo enabled duplicate and triplicate metabolic analysis of the same cell, which surprisingly continued to divide to the 16-cell stage. Last, we used microprobe single-cell CE-ESI-MS to uncover previously unknown reorganization of the single-cell metabolome as the dorsal progenitor cell from the 8-cell embryo formed the neural tissue fated clone through divisions to the 32-cell embryo, peering, for the first time, into the formation of metabolic single-cell heterogeneity during early development of a vertebrate embryo.

  13. Two-dimensional capillary zone electrophoresis-mass spectrometry for the characterization of intact monoclonal antibody charge variants, including deamidation products.

    PubMed

    Jooß, Kevin; Hühner, Jens; Kiessig, Steffen; Moritz, Bernd; Neusüß, Christian

    2017-08-12

    Capillary zone electrophoresis (CZE) is a powerful tool that is progressively being applied for the separation of monoclonal antibody (mAb) charge variants. Mass spectrometry (MS) is the desired detection method concerning identification of mAb variants. In biopharmaceutical applications, there exist optimized and validated electrolyte systems for mAb variant quantification. However, these electrolytes interfere greatly with the electrospray ionization (ESI) process. Here, a heart-cut CZE-CZE-MS setup with an implemented mechanical four-port valve interface was developed that used a generic ε-aminocaproic acid based background electrolyte in the first dimension and acetic acid in the second dimension. Interference-free, highly precise mass data (deviation less than 1 Da) of charge variants of trastuzumab, acting as model mAb system, were achieved. The mass accuracy obtained (low parts per million range) is discussed regarding both measured and calculated masses. Deamidation was detected for the intact model antibody, and related mass differences were significantly confirmed on the deglycosylated level. The CZE-CZE-MS setup is expected to be applicable to a variety of antibodies and electrolyte systems. Thus, it has the potential to become a compelling tool for MS characterization of antibody variants separated in ESI-interfering electrolytes. Graphical Abstract Two-dimensional capillary zone electrophoresis mass spectrometry for the characterization of intact monoclonal antibody (mAb) charge variants. A generic, but highly electrospray-interfering electrolyte system was used as first dimension for mAb charge variant separation and coupled to a volatile electrolyte system as second dimension via a four-port nanoliter valve. In this way, interference-free and precise mass spectrometric data of separated mAb charge variants, including deamidation products, were obtained.

  14. Bottom-up proteomics of Escherichia coli using dynamic pH junction preconcentration and capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry.

    PubMed

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

    2014-07-01

    We report the use of the dynamic pH junction based capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) for bottom-up proteomics with an electrokinetically pumped sheath-flow nanospray capillary electrophoresis-mass spectrometry (CE-MS) interface and both LTQ-XL and LTQ-Orbitrap-Velos mass spectrometers. Conventional injection of 20 nL of a 1 mg/mL BSA digest identified 37 peptides and produced 66% sequence coverage. In contrast, pH junction injection of 130 nL (or larger) of a 0.05 mg/mL BSA digest identified 40 peptides and produced 70% coverage using a pH 6.5 sample buffer and the LTQ. A 20 nL conventional injection of a 1 mg/mL Escherichia coli digest identified 508 peptides and 199 proteins with the LTQ. A 400 nL pH junction injection of a 0.1 mg/mL E. coli digest identified 527 peptides and 179 proteins with the LTQ. Triplicate technical replicates of a 0.01 mg/mL sample with 400-nL injection volume using a pH junction identified 288 ± 9 peptides and 121 ± 5 proteins with the LTQ. There was outstanding concordance in migration time between the pH junction and normal injection. The pH junction produced narrower peaks and significant concentration for all but the most acidic components in the sample. Compared with the conventional stacking method, the pH junction method can generate comparable performance for small injection volume (20 nL) and significantly better concentration performance for a large injection volume (200 nL). We also applied the pH junction to three intact standard proteins and observed a >10× increase in peak intensity compared to conventional injection.

  15. Molecularly imprinted polymer as in-line concentrator in capillary electrophoresis coupled with mass spectrometry for the determination of quinolones in bovine milk samples.

    PubMed

    Moreno-González, David; Lara, Francisco J; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2014-09-19

    In this work molecularly imprinted polymers have been evaluated as sorbent for the construction of an in-line solid phase extraction analyte concentrator in capillary electrophoresis coupled with mass spectrometry for the determination of the eight regulated veterinary quinolones in bovine milk samples. Different parameters affecting the analyte concentrator performance, such as sample pH, volume and composition of the elution plug and injection time, were studied. Sample volumes of 22μL (2bar for 15min) were loaded on the MISPE microcartridge and the retained analytes were eluted by injecting a plug of MeOH/H2O/NH3 (60/37/3 by volume) for 125s at 50mbar (60nL). The proposed method is simple for the monitoring of these antibiotic residues in milk samples, allowing the direct injection of the samples with minimum sample pretreatment, achieving limits of detection between 3.8 and 4.7μgkg(-1) and unequivocal identification of the compounds working in tandem mass spectrometry. Recoveries ranging from 70.0 to 102.3% were obtained and satisfactory intra-day and inter-day RSDs were achieved (≤12% and 15% respectively). Reproducibility among different constructed analyte concentrators showed RSD≤11%.

  16. A micellar electrokinetic chromatography-mass spectrometry approach using in-capillary diastereomeric derivatization for fully automatized chiral analysis of amino acids.

    PubMed

    Moldovan, Radu-Cristian; Bodoki, Ede; Kacsó, Timea; Servais, Anne-Catherine; Crommen, Jacques; Oprean, Radu; Fillet, Marianne

    2016-10-07

    In the context of bioanalytical method development, process automatization is nowadays a necessity in order to save time, improve method reliability and reduce costs. For the first time, a fully automatized micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) method with in-capillary derivatization was developed for the chiral analysis of d- and l-amino acids using (-)-1-(9-fluorenyl) ethyl chloroformate (FLEC) as labeling reagent. The derivatization procedure was optimized using an experimental design approach leading to the following conditions: sample and FLEC plugs in a 2:1 ratio (15s, 30mbar: 7.5s, 30mbar) followed by 15min of mixing using a voltage of 0.1kV. The formed diastereomers were then separated using a background electrolyte (BGE) consisting of 150mM ammonium perfluorooctanoate (APFO) (pH=9.5) and detected by mass spectrometry (MS). Complete chiral resolution was obtained for 8 amino acids, while partial separation was achieved for 6 other amino acid pairs. The method showed good reproducibility and linearity in the low micromolar concentration range. The applicability of the method to biological samples was tested by analyzing artificial cerebrospinal fluid (aCSF) samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Solid-phase extraction-capillary electrophoresis-mass spectrometry for the determination of tetracyclines residues in surface water by using carbon nanotubes as sorbent material.

    PubMed

    Suárez, B; Santos, B; Simonet, B M; Cárdenas, S; Valcárcel, M

    2007-12-14

    Last years chemical properties of carbon nanotubes (CNTs) have attracted high interest. One of the most important issues is the capability of CNTs to adsorb analytes on its surface. In this work, such property has been used to preconcentrate trace tetracyclines from environmental water samples at the trace level. Multi-walled carbon nanotubes (MWNTs) have showed higher capacity than other two single-walled carbon nanotubes (SWNTs). Preconcentration of the samples was performed in a flow system at-line coupled to the CE-MS equipment. The preconcentration of tetracyclines on MWNTs followed by capillary electrophoresis-mass spectrometry allows the detection of 0.30-0.69 microg/L of tetracyclines for the analysis of 10 mL of samples. Recoveries for the analysis of spiked samples ranged from 98.6 to 103.2% and the precision from 5.4 to 8.2%. Separation of tetracylines in the electrophoretic system was achieved using 50 mM formic acid at pH 2.0 as a background electrolyte. Atmospheric pressure electrospray ionization mass spectrometry detection was accomplished using 50:50 (v/v) methanol/water containing 0.5% (v/v) formic acid as a sheath liquid.

  18. Chiral Capillary Electrophoresis-Mass Spectrometry: Developments and Applications in the Period 2010-2015: A Review.

    PubMed

    Liu, Yijin; Shamsi, Shahab A

    2016-11-01

    The sensitive detection of chiral compounds by capillary electrophoresis (CE) in biological samples remains a significant challenge and is currently considered a bottleneck in many chiral analysis projects. Chiral CE-MS can significantly improve the limit of detection and provide high sensitivity compared with chiral CE-UV. Chiral selectors such as modified cyclodextrins (CDs) and polymeric surfactants (a.k.a. molecular micelles, MoMs) in electrokinetic chromatography (EKC), micellar electrokinetic chromatography (MEKC) and capillary electrochromatography (CEC) have been developed to address the need for high sensitivity by CE-MS. However, several problems remain to be investigated to fully understand the potential of these hyphenation modes. This review provides introduction to major chiral CE-MS modes for the novice and highlights the important working principles of each mode of chiral CE-MS. Next, recent practical developments and progress in chiral CE-MS dating from January 2010 to September 2015 are described. The achievements in clinical and biomedical sciences using a variety of chiral selectors such as CDs and MoMs in EKC-MS, MEKC-MS and CEC-MS are discussed. Finally, conclusions and future prospects of CE-MS in chiral analysis are drafted.

  19. A capillary electrophoresis system with dual capacitively coupled contactless conductivity detection and electrospray ionization tandem mass spectrometry.

    PubMed

    Francisco, Kelliton José Mendonça; do Lago, Claudimir Lucio

    2016-07-01

    A commercial system that is comprised of a CE coupled to an ESI triple quadrupole mass spectrometer was equipped with two capacitively coupled contactless conductivity detectors (C(4) Ds). The first C(4) D was positioned inside the original cartridge, and the second C(4) D was positioned as close as possible to the ESI probe entrance by using a 3D-printed support. The C(4) Ds electropherograms were matched to the ESI-MS electropherogram by correcting their timescales by the factor LT /LD , where LT and LD are the total capillary length and the length until the C(4) D, respectively. A general approach for method development supporting the simultaneous conductivity and MS detection is discussed, while application examples are introduced. These examples include the use of C(4) D as a simple device that dismiss the use of an EOF marker, a low-selectivity detector that continuously provide information about unexpected features of the sample, and even a detector that can be more sensitive than ESI-MS. The C(4) D used in this setup proved to have a smaller contribution to the peak broadening than ESI-MS, which allowed that a C(4) D, positioned at 12 cm from the inlet of an 80-cm-long capillary, could be used to foresee position and shape of the peaks being formed 6.8 times slower at the ESI-MS electropherogram.

  20. Analysis of active alkaloids in the Menispermaceae family by nonaqueous capillary electrophoresis-ion trap mass spectrometry.

    PubMed

    Chen, Qinhua; Zhang, Juan; Zhang, Wenpeng; Chen, Zilin

    2013-01-01

    A nonaqueous CE-IT MS with a nanospray ionization interface method was developed for the identification and quantification of tetrandrine (TET), fangchinoline (FAN), and sinomenine (SIN) using berberine as internal standard. The TET, FAN, and SIN standard solutions were directly infused into IT-MS for collecting MS(1-3) spectra. The major fragment ions of analytes were confirmed and possible main cleavage pathways of fragment ions were studied. A bare fused-silica capillary was used for separation of the analytes. A sheath liquid (50% aqueous methanol containing 0.2% acetic acid) to the capillary effluent with a nanoelectrospray ionization interface was added. Separation buffer comprised 80 mM solution of ammonium acetate, in a mixture of 70% methanol, 20% ACN, and 10% water, which also contained 1% acetic acid. The CE-MS method was validated for linearity, sensitivity, accuracy, and precision, and then used to determine the content of the above components. The detection limits of TET, FAN, and SIN are 0.05, 0.08, and 0.15 μg/mL, respectively. The precision was no more than 4.67% and the mean recovery of the analytes were 95.36-99.24%. This method was successfully applied to determine TET, FAN, and SIN in real samples radix Stephaniae tetrandrae and rhizomes of Menispermum dauricum.

  1. Capillary isoelectric focusing-tandem mass spectrometry and reversed-phase liquid chromatography-tandem mass spectrometry for quantitative proteomic analysis of differentiating PC12 cells by eight-plex isobaric tags for relative and absolute quantification.

    PubMed

    Zhu, Guijie; Sun, Liangliang; Keithley, Richard B; Dovichi, Norman J

    2013-08-06

    We report the application of capillary isoelectric focusing for quantitative analysis of a complex proteome. Biological duplicates were generated from PC12 cells at days 0, 3, 7, and 12 following treatment with nerve growth factor. These biological duplicates were digested with trypsin, labeled using eight-plex isobaric tags for relative and absolute quantification (iTRAQ) chemistry, and pooled. The pooled peptides were separated into 25 fractions using reversed-phase liquid chromatography (RPLC). Technical duplicates of each fraction were separated by capillary isoelectric focusing (cIEF) using a set of amino acids as ampholytes. The cIEF column was interfaced to an Orbitrap Velos mass spectrometer with an electrokinetically pumped sheath-flow nanospray interface. This HPLC-cIEF-electrospray-tandem mass spectrometry (ESI-MS/MS) approach identified 835 protein groups and produced 2,329 unique peptides IDs. The biological duplicates were analyzed in parallel using conventional strong-cation exchange (SCX)-RPLC-ESI-MS/MS. The iTRAQ peptides were first separated into eight fractions using SCX. Each fraction was then analyzed by RPLC-ESI-MS/MS. The SCX-RPLC approach generated 1,369 protein groups and 3,494 unique peptide IDs. For protein quantitation, 96 and 198 differentially expressed proteins were obtained with RPLC-cIEF and SCX-RPLC, respectively. The combined set identified 231 proteins. Protein expression changes measured by RPLC-cEIF and SCX-RPLC were highly correlated.

  2. Capillary sample

    MedlinePlus

    ... using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a limited amount of blood can be drawn using this method. The procedure has some risks (see below). Capillary ...

  3. Reproducible preparation of nanospray tips for capillary electrophoresis coupled to mass spectrometry using 3D printed grinding device.

    PubMed

    Tycova, Anna; Prikryl, Jan; Foret, Frantisek

    2016-04-01

    The use of high quality fused silica capillary nanospray tips is critical for obtaining reliable and reproducible electrospray/MS data; however, reproducible laboratory preparation of such tips is a challenging task. In this work, we report on the design and construction of low-cost grinding device assembled from 3D printed and commercially easily available components. Detailed description and characterization of the grinding device is complemented by freely accessible files in stl and skp format allowing easy laboratory replication of the device. The process of sharpening is aimed at achieving maximal symmetricity, surface smoothness and repeatability of the conus shape. Moreover, the presented grinding device brings possibility to fabricate the nanospray tips of desired dimensions regardless of the commercial availability. On several samples of biological nature (reserpine, rabbit plasma, and the mixture of three aminoacids), performance of fabricated tips is shown on CE coupled to MS analysis. The special interest is paid to the effect of tip sharpness.

  4. Potential of vancomycin for the enantiomeric resolution of FMOC-amino acids by capillary electrophoresis-ion-trap-mass spectrometry.

    PubMed

    Sánchez-Hernández, Laura; Domínguez-Vega, Elena; Montealegre, Cristina; Castro-Puyana, María; Marina, María Luisa; Crego, Antonio L

    2014-05-01

    The potential of the antibiotic vancomycin (VC) as chiral selector for the enantiomeric separation of amino acids by CE-ESI-MS/MS² was investigated for the first time in this work. Derivatization of amino acids with FMOC-Cl was carried out to enable their interaction with VC as well as the formation of precursor ions with larger m/z which were employed in MS² experiments. The partial filling of a coated capillary was employed to avoid the loss in MS sensitivity originated by the introduction of VC in the ionization source. Under optimized conditions, the simultaneous enantiomeric separation and unequivocal identification of 17 amino acids (two of them being nonprotein amino acids) took place in about 20 min with LODs in the micromolar range.

  5. Determination of non-metallic elements by capacitively coupled helium microwave plasma atomic emission spectrometry with capillary gas chromatography.

    PubMed

    Uchida, H; Berthod, A; Winefordner, J D

    1990-07-01

    A capacitively coupled microwave helium plasma with a tubular tantalum electrode was evaluated as an element selective detector for gas chromatography (GC). The end of a 10-m bonded fused capillary column was directly inserted into the tubular electrode without any switching system. A heated copper tube was used to house the part of the GC column that protruded from the oven. The optimisation of operating parameters, line selection, background emission and horizontal and vertical observation position is described. Analytical figures of merit including sensitivity, reproducibility, signal to background ratio, selectivity, dynamic range and limit of detection (LOD), were evaluated for carbon, hydrogen, chlorine and bromine emission. Limits of detection in the low ng range (20 pmol) were obtained for halogenated compounds using carbon emission, whereas LODs in the 0.1 micrograms range (2 nmol) were obtained using chlorine or bromine emission lines.

  6. Gold nanoparticles as intermediate ligands for polymer monolithic capillary microextraction of trace rare earth elements followed by inductively coupled plasma mass spectrometry detection

    NASA Astrophysics Data System (ADS)

    Cai, Yabing; Chen, Beibei; He, Man; Liu, Xiaolan; Bin, Hu

    2017-01-01

    In this work, a novel method of Au nanoparticles (NPs) modified polymer monolithic capillary microextraction (CME) on-line coupling with inductively coupled plasma-mass spectrometry (ICP-MS) was developed for the determination of trace rare earth elements (REEs) in environmental and biological samples. The poly(glycidyl methacrylate-ethylene dimethacrylate) monolithic capillary was prepared, functionalized with thiol ligands for the attaching of Au NPs, and then modified with mercaptosuccinic acid to provide massive carboxyl groups which have high affinity to REEs. With the modification of Au NPs, the adsorption capacity of the monolith towards target REEs has been improved by 3 to 6.5 times. Under the optimized conditions, the limits of detection of the developed method for REEs were in the range of 0.16 (Tb)-0.85 (Gd) ng L- 1. The enrichment factor was 25-fold with the sample throughput of 10 h- 1. And the relative standard deviations were between 2.7 (Lu) and 9.8% (Dy) (c = 10 ng L- 1, n = 9). The accuracy of the method was validated by the analysis of a standard stock solution of GSB04-1789-2004 and a Certified Reference Material of GBW07301a stream sediment. The proposed method was applied for the analysis of trace REEs in seawater samples as well as human whole blood with good recoveries. The prepared monolith is featured with strong anti-interference ability, superior adsorption capacity as well as long lifespan, and the developed monolithic CME-ICP-MS is sensitive, simple and rapid for the analysis of trace/ultra-trace REEs in environmental and biological samples with complex matrix.

  7. A capillary electrophoresis-mass spectrometry based method for the screening of β-secretase inhibitors as potential Alzheimer's disease therapeutics.

    PubMed

    Schejbal, Jan; Slezáčková, Lucie; Řemínek, Roman; Glatz, Zdeněk

    2017-03-03

    In this work a novel capillary electrophoresis-mass spectrometry (CE-MS) based method was developed and validated for the assay of β-secretase (BACE1) activity as a potential target for Alzheimer's disease (AD) treatment. In contrast with the typically used Förster resonance energy transfer (FRET) assays, an unlabelled decapeptide derived from the amyloid precursor protein BACE1 site with the "Swedish mutation" was used as the substrate. The CE usage enabled the enzymatic reaction to be carried out in as small a volume as 100μL in 60min with sufficient yields of proteolytic product, which was subsequently separated in a bare fused silica capillary using 12.5% acetic acid as a background electrolyte and detected by MS. The limits of detection and quantitation were estimated using the signal to noise ratio to be 5nM (S/N=3) and 15nM (S/N=10), respectively, both being well below the working range for kinetic and inhibition studies. Its applicability for the kinetic study of BACE1 was demonstrated using optimized enzyme assay conditions and the estimated kinetic parameter values were confirmed by classic CE-UV analyses. The method was finally used for the main purpose for which it was developed - to screen BACE1 inhibitors as potential AD therapeutics. The resulting kinetic and inhibition parameters values were compared to those published in the literature, which were almost exclusively obtained by FRET based assays. These comparisons brought up several issues that are further discussed below and favour the application of an unlabelled substrate. The proposed CE-MS based method offers a high-throughput capability for new drug development.

  8. Profiling the glycoforms of the intact alpha subunit of recombinant human chorionic gonadotropin by high-resolution capillary electrophoresis-mass spectrometry.

    PubMed

    Thakur, Dipak; Rejtar, Tomas; Karger, Barry L; Washburn, Nathaniel J; Bosques, Carlos J; Gunay, Nur S; Shriver, Zachary; Venkataraman, Ganesh

    2009-11-01

    With the rapid growth of complex heterogeneous biological molecules, effective techniques that are capable of rapid characterization of biologics are essential to ensure the desired product characteristics. To address this need, we have developed a method for analysis of intact glycoproteins based on high-resolution capillary electrophoretic separation coupled to an LTQ-FT mass spectrometer. We evaluated the performance of this method on the alpha subunit of mouse cell line-derived recombinant human chorionic gonadotrophin (r-alpha hCG), a protein that is glycosylated at two sites and is part of the clinically relevant gonadotrophin family. Analysis of r-alpha hCG, using capillary electrophoresis (CE) with a separation time under 20 min, resulted in the identification of over 60 different glycoforms with up to nine sialic acids. High-resolution CE-Fourier transform mass spectrometry (FT-MS) allowed separation and analysis of not only intact glycoforms with different numbers of sialic acids but also intact glycoforms that differed by the number and extent of neutral monosaccharides. The high mass resolution of the FT-MS enabled a limited mass range to be targeted for the examination of the protein glycoforms, simplifying the analysis without sacrificing accuracy. In addition, the limited mass range resulted in a fast scan speed that enhanced the reproducibility of the relative quantitation of individual glycoforms. The intact glycoprotein analysis was complemented with the analysis of the tryptic glycopeptides and glycans of r-alpha hCG to enable the assignment of glycan structures to individual sites, resulting in a detailed characterization of the protein. Samples of r-alpha hCG obtained from a CHO cell line were also analyzed and briefly shown to be significantly different from the murine cell line product. Taken together, the results suggest that the CE coupled to high-resolution FT-MS can be one of the effective tools for in-process monitoring as well as for

  9. Detection of trace levels of triclopyr using capillary gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry.

    PubMed

    Begley, P; Foulger, B E

    1988-04-01

    Triclopyr, after esterification, is shown to be a suitable candidate for detection by gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry forming a characteristic carboxylate anion which offers a high detection sensitivity. A detection limit of 70 fg reaching the ionizer is indicated. Low backgrounds and an absence of chemical interferences are shown for vegetation extracts, using a simple method of extraction and derivatisation. A similar behaviour is demonstrated for 2,4-D and 2,4,5-T.

  10. Quantitative determination of the neurotoxin β-N-methylamino-L-alanine (BMAA) by capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Kerrin, Elliott S; White, Robert L; Quilliam, Michael A

    2017-02-01

    Recent reports of the widespread occurrence of the neurotoxin β-N-methylamino-L-alanine (BMAA) in cyanobacteria and particularly seafood have raised concerns for public health. LC-MS/MS is currently the analytical method of choice for BMAA determinations but incomplete separation of isomeric and isobaric compounds, matrix suppression and conjugated forms are plausible limitations. In this study, capillary electrophoresis (CE) coupled with MS/MS has been developed as an alternative method for the quantitative determination of free BMAA. Using a bare fused silica capillary, a phosphate buffer (250 mM, pH 3.0) and UV detection, it was possible to separate BMAA from four isomers, but the limit of detection (LOD) of 0.25 μg mL(-1) proved insufficient for analysis of typical samples. Coupling the CE to a triple quadrupole MS was accomplished using a custom sheath-flow interface. The best separation was achieved with a 5 M formic acid in water/acetonitrile (9:1) background electrolyte. Strong acid hydrolysis of lyophilized samples was used to release BMAA from conjugated forms. Field-amplified stacking after injection was achieved by lowering sample ionic strength with a cation-exchange cleanup procedure. Quantitation was accomplished using isotope dilution with deuterium-labelled BMAA as internal standard. An LOD for BMAA in solution of 0.8 ng mL(-1) was attained, which was equivalent to 16 ng g(-1) dry mass in samples using the specified extraction procedure. This was comparable with LC-MS/MS methods. The method displayed excellent resolution of amino acid isomers and had no interference from matrix components. The presence of BMAA in cycad, mussel and lobster samples was confirmed by CE-MS/MS, but not in an in-house cyanobacterial reference material, with quantitative results agreeing with those from LC-MS/MS. Graphical Abstract CE-MS separation and detection of BMAA, its isomers and the internal standard BMAA-d3.

  11. Simultaneous enantioselective separation of azelastine and three of its metabolites for the investigation of the enantiomeric metabolism in rats. I. Liquid chromatography-ionspray tandem mass spectrometry and electrokinetic capillary chromatography.

    PubMed

    Heinemann, Ute; Blaschke, Gottfried; Knebel, Norbert

    2003-08-15

    Enantioselective separation methods and the enantioselective determination of the anti-allergic drug azelastine and of three of its main phase I metabolites in a biological matrix underwent chromatographic and electrophoretic investigations. An enantioselective assay of a coupling of HPLC using a beta-cyclodextrin chiral stationary phase to ionspray tandem mass spectrometry is presented. Additionally, this assay is compared to another enantioselective assay using electrokinetic capillary chromatography with beta-cyclodextrin and carboxymethyl-beta-cyclodextrin in polyacrylamide-coated capillaries. For capillary electrophoresis (CE) the importance of polyacrylamide coating for the validation of this separation method is highlighted. Extracted rat plasma samples of enantioselective metabolism studies were measured by both validated assays. Differences in the pharmacokinetics and pharmacodynamics were evaluated for the main substance azelastine and its main metabolite demethylazelastine. So, a first hint about the enantioselectivity of biotransformation of azelastine in rats was seen after oral application of either enantiomer or the racemate to rats.

  12. A microscale electrospray interface for on-line, capillary liquid chromatography/tandem mass spectrometry of complex peptide mixtures.

    PubMed

    Davis, M T; Stahl, D C; Hefta, S A; Lee, T D

    1995-12-15

    A microcapillary liquid chromatography (HPLC) system designed for the gradient elution of peptide and protein samples at flow rates < 1 microL/min has been coupled to a triple-sector quadrupole mass spectrometer via a simple sheathless electrospray interface (microspray). The microspray interface used a flame-drawn, uncoated, fused silica needle with tip outer diameters in the range of 15-20 microm and an opening less than 5 microm in diameter. Online sample filtration to prevent clogging of the drawn needle was accomplished by using a hydrophilic PVDF membrane filter integrated into the needle assembly. The spray potential (0.5-1 kV) was applied directly to the sample stream through the capillary union. Stable electrospray conditions were obtained over the full range of the gradient (0-90% acetonitrile in water) and was generally independent of flow rate. Both off-line and online analyses of proteins and peptide digest mixtures were performed at sample levels less than 10 fmol. HPLC parameters could be optimized for either rapid LC/MS analysis or enhanced performance in LC/MS/MS experiments by modulation of the eluting peak widths. Additionally, flow could be greatly reduced as selected components pass through the interface to prolong the time available to collect mass spectral data. The reduced spectral background and peak width manipulation facilitated the acquisition of peptide production spectra (MS/MS) using real-time, automated instrument control procedures.

  13. Dispersive liquid-liquid microextraction combined with capillary electrophoresis and time-of-flight mass spectrometry for urine analysis.

    PubMed

    Kohler, Isabelle; Schappler, Julie; Sierro, Tatiana; Rudaz, Serge

    2013-01-25

    The combination of dispersive liquid-liquid microextraction (DLLME) with capillary electrophoresis (CE) and a time-of-flight mass spectrometer (TOF-MS) was evaluated for the toxicological screening in urine samples. A methodology based on design of experiments (DOE) was implemented to increase the extraction efficiency. Dichloromethane and isopropanol were selected as the extraction and dispersing solvents, respectively. Seven factors for DLLME were screened with the help of a Plackett-Burmann DOE using two model compounds before fine investigation of the important parameters to maximise the compound extraction. These experiments were performed in the CE-UV configuration to overcome potential MS matrix effects. The performance of the entire procedure was then evaluated using CE-ESI-TOF-MS. With a preconcentration factor of more than 130, the highly sensitive DLLME-CE-ESI-TOF-MS method allowed for the detection of 30 toxicological compounds (i.e., amphetamines and their derivatives, opiates, cocaine and its metabolites and pharmaceuticals) in urine with limits of detection in the sub-ng/mL level and was used to analyse real toxicological samples. The combination of DLLME and CE was particularly attractive because of the small amount of organic solvents required.

  14. High Throughput Analysis of Chiral Compounds Using Capillary Electrochromatography (CEC) and CEC-Mass Spectrometry with Cellulose Based Stationary Phases

    PubMed Central

    Bragg, William; Shamsi, Shahab A.

    2014-01-01

    To fulfill the ever growing demand for rapid chiral analysis, this research presents an approach for highthroughput enantiomeric separations and sensitive detection of model chiral analytes using capillary electrochromatography (CEC) with UV and MS detection. This was achieved utilizing a short 7 cm CEC columns packed with cellulose tris (3,5-dimethyl-phenylcarbamate) (CDMPC) or sulfonated cellulose tris (3,5-dimethylphenylcarbamate) (CDMPC-SO3) chiral stationary phases (CSPs) applying outlet side injections in CEC-UV. The separation performance was compared between CDMPC and CDMPC-SO3 CSPs for rapid enantio-separation in CEC-UV mode. In addition, using a high sensitivity UV-flow cell in combination with outlet side injections, the S/N and hence the limit of detection of chiral drug could be improved. The 7-cm packed column was also used with traditional inlet injections for CEC coupled to a low-cost single-quadrupole MS. While outlet side injection was not possible in CEC-MS due to instrumentation constraints, the combined use of a short 7 cm column packed with CDMPC-SO3 CSP provided several fold higher throughput. Both CEC-UV and CEC-MS with short packed bed has the potential for a simple, sensitive and cost-effective method for enantiomeric drug profiling in biological samples. PMID:25264392

  15. Cobalt complexes as internal standards for capillary zone electrophoresis-mass spectrometry studies in biological inorganic chemistry.

    PubMed

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

    2017-01-02

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

  16. Parts-per-trillion detection of harmala alkaloids in Undaria pinnatifida algae by on-line solid phase extraction capillary electrophoresis mass spectrometry.

    PubMed

    Tascon, Marcos; Gagliardi, Leonardo G; Benavente, Fernando

    2017-02-15

    β-carboline alkaloids of the harmala group (HAlks)-a family of compounds with pharmacologic effects-can be found at trace levels (<25 μg kg(-1) algae) in the edible invasive algae Undaria pinnatifida, known commonly as wakame. In this study, we present a simple and sensitive method to detect and quantify at low parts-per-trillion levels the six HAlks more frequently found in those plants. The method is based on on-line solid phase extraction capillary electrophoresis mass spectrometry using a C18 sorbent. First, the methodology was optimized and validated with standard solutions through the use of ultraviolet (UV) and mass spectrometry (MS) detection. Second, the optimized method for MS detection was applied to an analysis of the HAlks in U. pinnatifida extracts. The method achieved limits of detection between 2 and 77 pg mL(-1) for standards, producing an analyte preconcentration of about 1000-times in comparison to CE-MS. Some matrix effects were observed for the complex wakame extracts, especially for the most polar HAlks (harmol and harmalol), which bear aromatic hydroxyl groups. Harmine, harmaline, and norharmane were not detected in the algal extracts, whereas harmane was found at 70 pg mL(-1) (70 ng kg(-1) dry algae). The results underscored that C18-SPE-CE-MS may be considered as a powerful method to detect trace levels of alkaloids and other bioactive small molecules in complex plant extracts.

  17. Field-amplified sample stacking for the detection of chemical warfare agent degradation products in low-conductivity matrices by capillary electrophoresis-mass spectrometry.

    PubMed

    Lagarrigue, Mélanie; Bossée, Anne; Bégos, Arlette; Delaunay, Nathalie; Varenne, Anne; Gareil, Pierre; Bellier, Bruno

    2008-01-18

    Preconcentration of chemical warfare agent degradation products (alkylphosphonic acids and alkyl alkylphosphonic acids) in low-conductivity matrices (purified water, tap water and local river water) by field-amplified sample stacking (FASS) was developed for capillary electrophoresis (CE) coupled to ion trap mass spectrometry. FASS was performed by adding a mixture of HCOONH(4) and NH(4)OH in appropriate concentrations to the sample. This allowed to control the conductivity and the pH of the sample in order to obtain FASS performances that are independent of analyte concentration. The influence of different parameters on FASS (sample to background electrolyte (BGE) conductivity ratio, injection volume and concentration of BGE) was studied to determine the optimal conditions and was rationalized by using the theoretical model developed by Burgi and Chien. A good correlation was obtained between the bulk electroosmotic velocity predicted by this model and the experimental value deduced from the migration time of the electroosmotic flow marker detected by mass spectrometry (MS). This newly developed method was successfully applied to the analysis of tap water and local river water fortified with the analytes and provided a 10-fold sensitivity enhancement in comparison to the signal obtained without preconcentration procedure. The quite satisfactory repeatability and linearity for peak areas obtained in the 0.5-5 microg mL(-1) concentration range allow quantitative analysis to be implemented. Limits of detection of 0.25-0.5 microg mL(-1) for the alkyl alkylphosphonic acids and of 0.35-5 microg mL(-1) for the alkylphosphonic acids were reached in tap water and river water.

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

    PubMed

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

    2014-09-05

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

  19. Determination of Wastewater Compounds in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry

    USGS Publications Warehouse

    Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.

    2006-01-01

    A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are indicators of wastewater or have endocrine-disrupting potential. These compounds include the alkylphenol ethoxylate nonionic surfactants, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Wastewater compounds in whole-water samples were extracted using continuous liquid-liquid extractors and methylene chloride solvent, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 0.5 microgram per liter averaged 72 percent ? 8 percent relative standard deviation. The concentration of 21 compounds is always reported as estimated because method recovery was less than 60 percent, variability was greater than 25 percent relative standard deviation, or standard reference compounds were prepared from technical mixtures. Initial method detection limits averaged 0.18 microgram per liter. Samples were preserved by adding 60 grams of sodium chloride and stored at 4 degrees Celsius. The laboratory established a sample holding-time limit prior to sample extraction of 14 days from the date of collection.

  20. Influence of diet on the proteome of Drosophila melanogaster as assessed by two-dimensional gel electrophoresis and capillary liquid chromatography-mass spectrometry: the hamburger effect revisited.

    PubMed

    Culwell, Thomas F; Thulin, Craig D; Merrell, Karen J; Graves, Steven W

    2008-09-01

    Proteomic biomarker discovery has been called into question. Diamandis hypothesized that seemingly trivial factors, such as eating a hamburger, may cause sufficient proteomic change as to confound proteomic differences. This has been termed the hamburger effect. Little is known about the variability of complex proteomes in response to the environment. Two methods-two-dimensional gel electrophoresis (2DGE) and capillary liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LCMS)-were used to study the hamburger effect in two cross-sections of the soluble fruit fly proteome. 2DGE measured abundant proteins, whereas LCMS measured small proteins and peptides. Proteomic differences between males and females were first evaluated to assess the discriminatory capability of the methods. Likewise, wild-type and white-eyed flies were analyzed as a further demonstration that genetically based proteomic differences could be observed above the background analytical variation. Then dietary interventions were imposed. Ethanol was added to the diet of some populations without significant proteomic effect. However, after a 24-h fast, proteomic differences were found using LCMS but not 2DGE. Even so, only three of approximately 1000 molecular species were altered significantly, suggesting that the influence of even an extreme diet change produced only modest proteomic variability, and that much of the fruit fly proteome remains relatively constant in response to diet. These experiments suggest that proteomics can be a viable approach to biomarker discovery.

  1. Metabolic profiling for the identification of Huntington biomarkers by on-line solid-phase extraction capillary electrophoresis mass spectrometry combined with advanced data analysis tools.

    PubMed

    Pont, Laura; Benavente, Fernando; Jaumot, Joaquim; Tauler, Romà; Alberch, Jordi; Ginés, Silvia; Barbosa, José; Sanz-Nebot, Victoria

    2016-03-01

    In this work, an untargeted metabolomic approach based on sensitive analysis by on-line solid-phase extraction capillary electrophoresis mass spectrometry (SPE-CE-MS) in combination with multivariate data analysis is proposed as an efficient method for the identification of biomarkers of Huntington's disease (HD) progression in plasma. For this purpose, plasma samples from wild-type (wt) and HD (R6/1) mice of different ages (8, 12, and 30 weeks), were analyzed by C18 -SPE-CE-MS in order to obtain the characteristic electrophoretic profiles of low molecular mass compounds. Then, multivariate curve resolution alternating least squares (MCR-ALS) was applied to the multiple full scan MS datasets. This strategy permitted the resolution of a large number of metabolites being characterized by their electrophoretic peaks and their corresponding mass spectra. A total number of 29 compounds were relevant to discriminate between wt and HD plasma samples, as well as to follow-up the HD progression. The intracellular signaling was found to be the most affected metabolic pathway in HD mice after 12 weeks of birth, when mice already showed motor coordination deficiencies and cognitive decline. This fact agreed with the atrophy and dysfunction of specific neurons, loss of several types of receptors, and changed expression of neurotransmitters.

  2. Structural analysis of low molecular weight heparin by ultraperformance size exclusion chromatography/time of flight mass spectrometry and capillary zone electrophoresis.

    PubMed

    Zhang, Qianqian; Chen, Xi; Zhu, Zhijia; Zhan, Xueqiang; Wu, Yanfang; Song, Lankun; Kang, Jingwu

    2013-02-05

    Although low molecular weight heparins (LMWHs) have been used as anticoagulant agents for over 2 decades, their structures have not been fully characterized. In this work, we propose a new strategy for the comprehensive structural analysis of LMWHs based on the combination of ultraperformance size exclusion chromatography/electrospray quadruple time-of-flight-mass spectrometry (UPSEC/Q-TOF-MS) and capillary zone electrophoresis (CZE). More than 70 components, including oligosaccharides with special structures such as 1,6-anhydro rings, saturated uronic acid at the nonreducing end and odd-numbered saccharides units were identified with UPSEC/Q-TOF-MS. Furthermore, a more detailed compositional analysis was accomplished by CZE analysis. PEG10000 and MgCl(2) were added to the background electrolyte to separate those saccharides with the nearly same charge-to-mass ratio. Baseline separation and quantification of all the building blocks of the most complex LMWH, namely, enoxaparin, which include 10 disaccharides, 1 trisaccharide, 2 tetrasaccharides, and, of particular importance, 4 1,6-anhyro derivatives, was achieved using CZE for the first time. Additionally, the peaks of oligosaccharides, in the absence of commercially available standards, were assigned on the basis of the linear correlation between the electrophoretic mobilities of oligosaccharides and their charge-to-mass ratios. These two approaches are simple and robust for structural analysis of LMWHs.

  3. Combining Capillary Electrophoresis Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry and Stable Isotopic Labeling Techniques for Comparative Crustacean Peptidomics

    PubMed Central

    Wang, Junhua; Zhang, Yuzhuo; Xiang, Feng; Zhang, Zichuan; Li, Lingjun

    2010-01-01

    Herein we describe a sensitive and straightforward off-line capillary electrophoresis (CE) matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) interface in conjunction with stable isotopic labeling (SIL) technique for comparative neuropeptidomic analysis in crustacean model organisms. Two SIL schemes, including a binary H/D formaldehyde labeling technique and novel, laboratory-developed multiplexed dimethylated leucine-based isobaric tagging reagents, have been evaluated in these proof-of-concept experiments. We employ these isotopic labeling techniques in conjunction with CE-MALDI MS for quantitative peptidomic analyses of the pericardial organs isolated from two crustacean species, the European green crab Carcinus maenas and the blue crab Callinectes sapidus. Isotopically labeled peptide pairs are found to co-migrate in CE fractions and quantitative changes in relative abundances of peptide pairs are obtained by comparing peak intensities of respective peptide pairs. Several neuropeptide families exhibit changes in response to salinity stress, suggesting potential physiological functions of these signaling peptides. PMID:20334868

  4. 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.

  5. Preparation and evaluation of an immunoaffinity sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry.

    PubMed

    Medina-Casanellas, Silvia; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

    2012-03-02

    In this study, we explored a procedure for the preparation of an immunoaffinity (IA) sorbent for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). We followed a site-specific antibody immobilization approach based on the covalent attachment of the oxidized antibodies through their carbohydrate moieties to hydrazide silica particles, using a polyclonal antibody against Endomorphin 1 and 2 (End1 and End2). The main features of the IA sorbent were studied, such as the amount of hydrazide groups and antibodies attached onto oxidized diol silica particles. Once the procedure was optimized, standard solutions of End1 and End2 were used in order to establish the IA-SPE-CE-MS methodology. Acceptable repeatability, reproducibility and linearity range values were obtained for the proposed methodology. The limits of detection (LODs) of 1 ng mL(-1) were approximately 100-fold better than those obtained by CE-MS. Selectivity of the IA sorbent was good but some cross-reactivity against Dynorphin A (1-7) was observed when a mixture of several opioid peptides was analyzed. Human plasma samples spiked with End1 and End2 were also analyzed and both peptides could be detected down to 100 ng mL(-1).

  6. Analysis of [3',3'-d(2)]-nicotine and [3',3'-d(2)]-cotinine by capillary liquid chromatography-electrospray tandem mass spectrometry.

    PubMed

    Murphy, Sharon E; Villalta, Peter; Ho, Sing-Wei; von Weymarn, Linda B

    2007-09-15

    A selective and sensitive LC/MS/MS assay was developed for the quantification of d(2)-nicotine and d(2)-cotinine in plasma of current and past smokers administered d(2)-nicotine. After solid phase extraction and liquid-liquid extraction, HPLC separation was achieved on a capillary hydrophilic interaction chromatography phase column. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated for d(2)-nicotine (0.03-6.0 ng/ml plasma) and d(2)-cotinine (0.15-25 ng/ml plasma). The lower limits of quantitation were 0.15 ng/ml and 0.25 ng/ml for d(2)-nicotine and d(2)-cotinine, respectively. The coefficient of variation was 3.7% for d(2)-nicotine and 2.5% for d(2)-cotinine. The method was applied to two ongoing studies of d(2)-nicotine metabolism in prior and current smokers. Preliminary analysis of a subset of subjects from these studies detected a significantly lower rate of nicotine conversion to cotinine by past smokers compared to current smokers.

  7. Global Metabolomic and Isobaric Tagging Capillary Liquid Chromatography–Tandem Mass Spectrometry Approaches for Uncovering Pathway Dysfunction in Diabetic Mouse Aorta

    PubMed Central

    2015-01-01

    Despite the prevalence of diabetes and the global health risks it poses, the biochemical pathogenesis of diabetic complications remains poorly understood with few effective therapies. This study employs capillary liquid chromatography (capLC) and tandem mass spectrometry (MS/MS) in conjunction with both global metabolomics and isobaric tags specific to amines and carbonyls to probe aortic metabolic content in diabetic mice with hyperglycemia, hyperlipidemia, hypertension, and stenotic vascular damage. Using these combined techniques, metabolites well-characterized in diabetes as well as novel pathways were investigated. A total of 53 986 features were detected, 719 compounds were identified as having significant fold changes (thresholds ≥2 or ≤0.5), and 48 metabolic pathways were found to be altered with at least 2 metabolite hits in diabetic samples. Pathways related to carbonyl stress, carbohydrate metabolism, and amino acid metabolism showed the greatest number of metabolite changes. Three novel pathways with previously limited or undescribed roles in diabetic complications—vitamin B6, propanoate, and butanoate metabolism—were also shown to be altered in multiple points along the pathway. These discoveries support the theory that diabetic vascular complications arise from the interplay of a myriad of metabolic pathways in conjunction with oxidative and carbonyl stress, which may provide not only new and much needed biomarkers but also insights into novel therapeutic targets. PMID:25368974

  8. Sensitive determination of parabens in human urine and serum using methacrylate monoliths and reversed-phase capillary liquid chromatography-mass spectrometry.

    PubMed

    Carrasco-Correa, Enrique Javier; Vela-Soria, Fernando; Ballesteros, Oscar; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel

    2015-01-30

    A method for the determination of parabens in human urine and serum by capillary liquid chromatography (cLC) with UV-Vis and mass spectrometry (MS) detection using methacrylate ester-based monolithic columns has been developed. The influence of composition of polymerization mixture was studied. The optimum monolith was obtained with butyl methacrylate monomer at 60/40% (wt/wt) butyl methacrylate/ethylene dimethacrylate ratio and 50wt% porogens (composed of 36wt% of 1,4-butanediol, 54wt% 1-propanol and 10wt% water). Baseline resolution of analytes was achieved through a mobile phase of acetonitrile/water in gradient elution mode. Additionally, dispersive liquid-liquid microextraction (DLLME) was combined with both cLC-UV-Vis and cLC-MS to achieve the determination of parabens in human urine and serum samples with very low limits of detection. Satisfactory intra- and inter-day repeatabilities were obtained in UV-Vis and MS detection, although the latter provided lower detection limits (up to 300-fold) than the UV-Vis detection. Recoveries for the target analytes from spiked biological samples ranged from 95.2% to 106.7%. The proposed methodology for the ultra-low determination of parabens in human urine and serum samples is simple and fast, the consumption of reagents is very low, and very small samples can be analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Combining peptide modeling and capillary electrophoresis-mass spectrometry for characterization of enzymes cleavage patterns: recombinant versus natural bovine pepsin A.

    PubMed

    Simó, Carolina; González, Ramón; Barbas, Coral; Cifuentes, Alejandro

    2005-12-01

    Nowadays there is an increasing number of recombinant enzymes made available to industry. Before replacing the use of natural enzymes with their cognate recombinant counterparts, one important issue to address is their actual equivalence. For a given recombinant proteolytic enzyme, its equivalence can be investigated by comparing its cleavage specificity with that obtained from the natural enzyme. This is mostly done by analyzing the fragments (i.e., peptidic map) attained after enzymatic digestion of a given protein used as substrate. The peptidic maps obtained are typically characterized using separation techniques together with MS and MS/MS systems. However, these procedures are known to be difficult and labor-intensive. In this work, the combined use of a theoretical model that relates electrophoretic behavior of peptides to their sequence together with capillary electrophoresis-mass spectrometry (CE-MS) is proposed to characterize in a very fast and simple way the cleavage specificity of new recombinant enzymes. Namely, the effectiveness of this procedure is demonstrated by analyzing in few minutes the fragments obtained from a protein hydrolysated using recombinant and natural pepsin A. The usefulness of this strategy is further corroborated by CE-MS/MS. The proposed procedure is applicable in many other proteomic studies involving CE-MS of peptides.

  10. Potential of capillary electrophoresis mass spectrometry for the characterization and monitoring of amine-derivatized naphthenic acids from oil sands process-affected water.

    PubMed

    MacLennan, Matthew S; Tie, Cai; Kovalchik, Kevin; Peru, Kerry M; Zhang, Xinxiang; Headley, John V; Chen, David D Y

    2016-11-01

    Capillary electrophoresis coupled to mass spectrometry (CE-MS) was used for the analysis of naphthenic acid fraction compounds (NAFCs) of oil sands process-affected water (OSPW). A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE-MS in less than 15min. Time of flight MS analysis (TOFMS), optimized for high molecular weight ions, showed NAFCs between 250 and 800m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs (between 100 and 450m/z) are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30% (V/V) methanol in water and 2% (V/V) formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE-MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500m/z. Copyright © 2016. Published by Elsevier B.V.

  11. Polymer monolithic capillary microextraction on-line coupled with inductively coupled plasma-mass spectrometry for the determination of trace Au and Pd in biological samples

    NASA Astrophysics Data System (ADS)

    Liu, Xiaolan; He, Man; Chen, Beibei; Hu, Bin

    2014-11-01

    A novel method based on on-line polymer monolithic capillary microextraction (CME)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of trace Au and Pd in biological samples. For this purpose, poly(glycidyl methacrylate-ethylene dimethacrylate) monolith was prepared and functionalized with mercapto groups. The prepared monolith exhibited good selectivity to Au and Pd, and good resistance to strong acid with a long life span. Factors affecting the extraction efficiency of CME, such as sample acidity, sample flow rate, eluent conditions and coexisting ion interference were investigated in detail. Under the optimal conditions, the limits of detection (LODs, 3σ) were 5.9 ng L- 1 for Au and 8.3 ng L- 1 for Pd, and the relative standard deviations (RSDs, c = 50 ng L -1, n = 7) were 6.5% for Au and 1.1% for Pd, respectively. The developed method was successfully applied to the determination of Au and Pd in human urine and serum samples with the recovery in the range of 84-118% for spiked samples. The developed on-line polymer monolithic CME-ICP-MS method has the advantages of rapidity, simplicity, low sample/reagent consumption, high sensitivity and is suitable for the determination of trace Au and Pd in biological samples with limited amount available and complex matrix.

  12. Stable, reproducible, and automated capillary zone electrophoresis-tandem mass spectrometry system with an electrokinetically pumped sheath-flow nanospray interface.

    PubMed

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

    2014-01-31

    A PrinCE autosampler was coupled to a Q-Exactive mass spectrometer by an electrokinetically pumped sheath-flow nanospray interface to perform automated capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS). 20ng aliquots of an Escherichia coli digest were injected to evaluate the system. Eight sequential injections over an 8-h period identified 1115±70 (relative standard deviation, RSD=6%) peptides and 270±8 (RSD=3%) proteins per run. The average RSDs of migration time, peak intensity, and peak area were 3%, 24% and 19%, respectively, for 340 peptides with high intensity. This is the first report of an automated CZE-ESI-MS/MS system using the electrokinetically pumped sheath-flow nanospray interface. The results demonstrate that this system is capable of reproducibly identifying over 1000 peptides from an E. coli tryptic digest in a 1-h analysis time. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Development of a fast capillary electrophoresis-time-of-flight mass spectrometry method for the speciation of organotin compounds under separation conditions of high electrical field strengths.

    PubMed

    Malik, Ashok Kumar; Grundmann, Marco; Matysik, Frank-Michael

    2013-11-15

    A novel approach has been developed for the separation of organotin species with capillary electrophoresis hyphenated to time-of-flight mass spectrometry. It has been applied to the development of a method for the determination and speciation of organotin compounds namely, dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPT) and triphenyltin (TPT) in water samples. Experiments were made with a special laboratory constructed CE instrument. A non-aqueous buffer system compatible with TOF-MS has been developed using ammonium acetate-acetic acid (50 mM and 1 M) in acetonitrile: methanol (80:20). The total analysis time is less than 3 min for these compounds under the conditions developed. The method has been applied successfully to the determination of these compounds in river water samples. Detection limits of the CE-TOF-MS method were between 1 and 8×10(-7) M, and between 2 and 11×10(-9) M (0.46 to 3.2 µg L(-1)) when used in conjunction with solid phase extraction. The short analysis time as well as good sensitivity and selectivity make it a useful approach for the fast screening of organotin compounds.

  14. A metabolomic approach to clarifying the effect of AST-120 on 5/6 nephrectomized rats by capillary electrophoresis with mass spectrometry (CE-MS).

    PubMed

    Akiyama, Yasutoshi; Takeuchi, Yoichi; Kikuchi, Koichi; Mishima, Eikan; Yamamoto, Yasuaki; Suzuki, Chitose; Toyohara, Takafumi; Suzuki, Takehiro; Hozawa, Atsushi; Ito, Sadayoshi; Soga, Tomoyoshi; Abe, Takaaki

    2012-11-14

    The oral adsorbent AST-120 is composed of spherical carbon particles and has an adsorption ability for certain small-molecular-weight compounds that accumulate in patients with chronic kidney disease (CKD). So far, very few compounds are known to be adsorbed by AST-120 in vivo. To examine the effect of AST-120 in vivo, we comprehensively evaluated the plasma concentrations of 146 compounds (61 anions and 85 cations) in CKD model rats, with or without four weeks of treatment with AST-120. By capillary electrophoresis with mass spectrometry, we identified 6 anions and 17 cations that were significantly decreased by AST-120 treatment. In contrast, we also identified 2 cations that were significantly increased by AST-120. Among them, 4 anions, apart from indoxyl sulfate and hippurate, and 19 cations were newly identified in this study. The plasma levels of N-acetyl-neuraminate, 4-pyridoxate, 4-oxopentanoate, glycine, γ-guanidinobutyrate, N-γ-ethylglutamine, allantoin, cytosine, 5-methylcytosine and imidazole-4-acetate were significantly increased in the CKD model compared with the sham-operated group, and were significantly decreased by AST-120 treatment. Therefore, these 10 compounds could be added as uremic compounds that indicate the effect of AST-120 treatment. This study provides useful information not only for identifying the indicators of AST-120, but also for clarifying changes in the metabolic profile by AST-120 treatment in the clinical setting.

  15. Arsenic speciation in rice by capillary electrophoresis/inductively coupled plasma mass spectrometry: enzyme-assisted water-phase microwave digestion.

    PubMed

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

    2015-04-01

    We report an analytical methodology for the quantification of common arsenic species in rice and rice cereal using capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICPMS). An enzyme (i.e., α-amylase)-assisted water-phase microwave extraction procedure was used to extract four common arsenic species, including dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenite [As(III)], and arsenate [As(V)] from the rice matrices. The addition of the enzyme α-amylase during the extraction process was necessary to reduce the sample viscosity, which subsequently increased the injection volume and enhanced the signal response. o-Arsanilic acid (o-ASA) was added to the sample solution as a mobility marker and internal standard. The obtained repeatability [i.e., relative standard deviation (RSD %)] of the four arsenic analytes of interest was less than 1.23% for elution time and 2.91% for peak area. The detection limits were determined to be 0.15-0.27 ng g(-1). Rice standard reference materials SRM 1568b and CRM 7503-a were used to validate this method. The quantitative concentrations of each organic arsenic and summed inorganic arsenic were found within 5% difference of the certified values of the two reference materials.

  16. A method for quantitating the intracellular metabolism of AZT amino acid phosphoramidate pronucleotides by capillary high-performance liquid chromatography-electrospray ionization mass spectrometry.

    PubMed

    Kim, Jisook; Park, Soobong; Tretyakova, Natalia Y; Wagner, Carston R

    2005-01-01

    A methodology has been developed for the analysis of the intracellular metabolism of 3'-azido-3'-deoxythymidine (AZT) amino acid phosphoramidates utilizing reverse-phase high-performance liquid chromatography interfaced with negative ion electrospray ionization mass spectrometry (LC/ESI(-) -MS). The presented work demonstrates the potential of capillary LC/MS and LC/MS/MS to identify and quantitate the cellular uptake and metabolism of nucleoside phosphoramidate. Significant intracellular amounts of D- and L-phenylalanine methyl ester or D- and L-tryptophan methyl ester AZT phosphoramidates were observed for human T-lymphoblastoid leukemia (CEM) cells incubated for 2 and 4 h with the prodrugs. AZT-MP was the primary metabolite observed for human T-lymphoblastoid leukemia (CEM) cells. In this paper, the details of using LC/MS to analyze AZT amino acid phosphoramidates in biological samples are discussed. LC/MS is an efficient method for analyzing multiple samples containing several analytes in a short period of time. The method also provides high selectivity and sensitivity, and requires minimal sample preparation. This approach should be broadly applicable for the analysis of the intracellular metabolism of nucleoside prodrugs and pronucleotides.

  17. Analysis of O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its degradation products by packed capillary liquid chromatography-electrospray mass spectrometry.

    PubMed

    D'Agostino, P A; Hancock, J R; Provost, L R

    1999-04-02

    Packed capillary column liquid chromatography (LC)-electrospray mass spectrometry (ESI-MS) was used for the first time to detect and identify O-ethyl, S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its degradation products, including compounds containing a P-CH3 bond, bis(diisopropylamino)thioalkanes and ureas commonly employed as VX stabilizers. The reported ESI-MS data were generally acquired with a higher sampling cone voltage, a setting that promoted collisionally activated dissociation, and resulted in the acquisition in informative mass spectra containing both molecular and product ion information. The developed method appears to be an attractive alternative to GC-MS for the analysis of aqueous sample containing the degradation products of VX, since they may be analysed directly with little risk of thermal decomposition and without the need for additional sample handling or derivatization. Application of this method to a degraded VX sample resulted in the detection of a number of novel polar and higher-molecular-mass degradation products, not previously associated with VX during GC-MS analysis.

  18. Small protein biomarkers of culture in Bacillus spores detected using capillary liquid chromatography coupled with matrix assisted laser desorption/ionization mass spectrometry

    SciTech Connect

    Wunschel, David S.; Wahl, Jon H.; Willse, Alan R.; Valentine, Nancy B.; Wahl, Karen L.

    2006-10-20

    Capillary liquid chromatography (cLC) coupled with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF-MS) was used to compare small proteins and peptides extracted from Bacillus subtilis spores grown on four different media. A single, efficient protein separation, compatible with MALDI-MS analysis, was employed to reduce competitive ionization between proteins, and thus interrogate more proteins than possible using direct MALDI-MS. The MALDI-MS data files for each fraction are assembled as two dimensional data sets of retention time and mass information. This method of visualizing small protein data required careful attention to background correction as well as mass and retention time variability. The resulting data sets were used to create comparative displays of differences in protein profiles between different spore preparations. Protein differences were found between two different solid media in both phase bright and phase dark conditions. The protein differences between two different liquid media were also examined. As an extension of this method, we have demonstrated that candidate protein biomarkers can be trypsin digested to provide identifying peptide fragment information following the cLC-MALDI experiment. We have demonstrated this method on two markers and utilized acid breakdown information to identify one additional marker for this organism. The resulting method can be used to identify discriminating proteins as potential biomarkers of growth media, which might ultimately be used for source attribution.

  19. Combination of dynamic pH junction with capillary electrophoresis-mass spectrometry for the determination of systemins in plant samples.

    PubMed

    Bai, Yu; Chang, Cuilan; Du, Fuyou; Tan, Zhijing; Bai, Yu; Liu, Huwei

    2014-07-01

    Systemin is an important group of plant peptide hormones participating in the regulation of plant defensive responses. An improved method, based on dynamic pH junction and capillary electrophoresis-quadrupole time-of-flight mass spectrometry, was developed for online enrichment and sensitive determination of trace systemins in plants. After optimization, the online enrichment factors for six target systemins ranged from 90- to 127-fold. The detection limits reached lower than 0.5 nM, which were comparable with the sensitivity of LC-MS method. Satisfactory quantitative results were obtained in terms of linearity (R(2) ≥ 0.993), dynamic range (3-120 ng/mL), and reproducibility (≤6.7%). For the analysis of real plant samples, a rapid sample preparation method was developed, using two steps of SPE purification with different retention and separation mechanisms. Finally, this method realized the successful detection of tomato systemin and tobacco hydroxyproline-rich systemin I from plant leaves with shorter analysis time.

  20. Separation of stereoisomers of several furan derivatives by capillary gas chromatography-mass spectrometry, supercritical fluid chromatography, and liquid chromatography using chiral stationary phases.

    PubMed

    Kasai, Hiroko F; Tsubuki, Masayoshi; Takahashi, Kazunori; Shirao, Mika; Matsumoto, Yohichiro; Honda, Toshio; Seyama, Yoshiyuki

    2002-11-15

    The direct separation of several stereoisomers (enantiomers and geometrical isomers) of furan derivatives, important intermediates for the synthesis of physiologically active natural products, was achieved using capillary gas chromatography/mass spectrometry with a per-O-methyl-beta-cyclodextrin, supercritical fluid chromatography and high-performance liquid chromatography with a tris(3,5-dimethylphenylcarbamate) of cellulose or amylose for the chiral stational phases, respectively. The temperature dependence of the peak resolution (Rs) and the retention factor (k) over the range of 110-130 degrees was studied using crotyl furfuryl ether in gas chromatography. Successive increases in the Rs value and of the difference between the k value of the E-isomer and the k value of the Z-isomer were observed when the gradient temperature was decreased. The per-O-methyl-beta-cyclodextrin column was suitable for use with volatile furan ethers whose molecular masses are between 150 and 180. In conclusion, the separation of thermally unstable furan derivatives was accomplished using supercritical fluid chromatography and high-performance liquid chromatography.

  1. Capillary electrophoresis coupled to mass spectrometry employing hexafluoro-2-propanol for the determination of nucleosides and nucleotide mono-, di- and tri-phosphates in baby foods.

    PubMed

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

    2017-10-15

    The present work describes a method for the simultaneous determination of unmodified nucleosides and nucleotide mono-, di- and tri-phosphates by capillary electrophoresis coupled to mass spectrometry (CE-MS). The use of hexafluoro-2-propanol (HFIP) in the separation medium, and as an additive to the sheath liquid of the electrospray interface (ESI), generated a highly efficient and sensitive method. Instrumental limits of detection in the range of 14-53ngmL(-1) for nucleosides and 7-23, 20-49 and 64-124ngmL(-1) for nucleotide mono-, di-, and tri-phosphates, respectively, were found. Sample treatment involved diluting an aliquot of baby food with ultra-high quality water and applying centrifugation-assisted ultrafiltration (CUF). The proposed method was validated and used to analyse a variety of baby food samples (16 in total) such as fish, meat, fruits, and baby dairy desserts that may endogenously contain these analytes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Solid phase microextraction capillary gas chromatography combined with furnace atomization plasma emission spectrometry for speciation of mercury in fish tissues

    NASA Astrophysics Data System (ADS)

    Grinberg, Patricia; Campos, Reinaldo C.; Mester, Zoltan; Sturgeon, Ralph E.

    2003-03-01

    The use of solid phase microextraction in conjunction with tandem gas chromatography-furnace atomization plasma emission spectrometry (SPME-GC-FAPES) was evaluated for the determination of methylmercury and inorganic mercury in fish tissue. Samples were digested with methanolic potassium hydroxide, derivatized with sodium tetraethylborate and extracted by SPME. After the SPME extraction, species were separated by GC and detected by FAPES. All experimental parameters were optimized for best separation and analytical response. A repeatability precision of typically 2% can be achieved with long-term (3 months) reproducibility precision of 4.3%. Certified Reference Materials DORM-2, DOLT-2 and TORT-2 from the National Research Council of Canada were analyzed to verify the accuracy of this technique. Detection limits of 1.5 ng g -1 for methylmercury and 0.7 ng g -1 for inorganic mercury in biological tissues were obtained.

  3. Determination of perfluorobutane in rat blood by automatic headspace capillary gas chromatography and selected ion monitoring mass spectrometry.

    PubMed

    Hvattum, E; Normann, P T; Oulie, I; Uran, S; Ringstad, O; Skotland, T

    2001-01-01

    A new contrast agent (Sonazoid; NC100100) for ultrasound imaging has been developed. It is an aqueous suspension of lipid stabilised perfluorobutane (PFB) gas microbubbles. An automatic headspace capillary gas-chromatographic mass spectrometric method using electron impact ionisation was developed for analysis of Sonazoid PFB in rat blood. The calibration standards were gaseous PFB dissolved in ethanol in the range of 0.5-5000 ng PFB. Fluorotrichloromethane (CFC 11) was used as an internal standard of the method and the MS detector was set to single ion monitoring of the base fragment ions of PFB (m/z 69 and 119) and CFC 11 (m/z 101). The calibration graph, made by plotting the peak area ratios of PFB (m/z 69) to CFC 11(m/z 101) against the amount of PFB, was fitted to a second-order polynomial equation with weighting 1/y2 and found to be reproducible. The limit of quantification of the method was set to 0.4 ng PFB. The between-day variation of the method was below 9.2% relative standard deviation (RSD) and the within-day variation of the method was below 7.6% RSD. The accuracy of the method, as compared to Coulter counter, was estimated by determination of PFB in samples where Sonazoid was added to saline and found to range from 91.5% to 105.2%. PFB, added as Sonazoid, was found to be stable for at least 7 months in rat blood samples when stored at -20 degrees C.

  4. Analysis of neutral nitromusks in incenses by capillary electrophoresis in organic solvents and gas chromatography-mass spectrometry.

    PubMed

    Gotti, Roberto; Fiori, Jessica; Mancini, Francesca; Cavrini, Vanni

    2005-09-01

    Nitromusks used as fragrances in a variety of personal-care products, cleansers, and domestic deodorants, including incense sticks, are neutral nitro aromatic compounds; some of these have been reported as photosensitizers. In this work, their analysis was performed by capillary electrophoresis (CE) in a methanol-based background electrolyte (BGE). In particular, a 10 mM solution of citric acid in methanol was used; under these conditions the strong suppression of the electroosmotic flow favored the use of negatively charged surfactants as additives for the anodic migration of the studied analytes. To this end, sodium taurodeoxycholate (TDC) was supplemented at high concentration (190 mM) to the organic background electrolyte (BGE), showing strong indication of the ability to give micelle-like aggregates. Since nitromusks are characterized by the presence of a nitroaromatic ring with low charge density, their association with TDC aggregates can be ascribed to donor-acceptor interactions. Separation of musk xylene, musk ketone, and the banned musk moskene and musk ambrette was obtained under full nonaqueous BGE; the addition of relatively small water percentages (15% v/v) was found to be useful in improving the separation of pairs of adjacent peaks. Under optimized conditions (190 mM sodium TDC in methanol-water, 85-15 v/v containing citric acid 10 mM) the system was applied to the analysis of nitromusks in incense sticks extracted with methanol. The results were compared with those obtained by the analysis of the same samples using gas chromatography with mass detector. The expected different selectivity of separation obtained using the two techniques can be useful in the unambiguous determination of the analytes; furthermore, a substantial accord of the preliminary quantitative results achieved with the two methods was assumed as the confirmation of the potential reliability of CE performed with high percentage of organic solvent.

  5. High-Throughput Proteomics Using High Efficiency Multiple-Capillary Liquid Chromatography With On-Line High-Performance ESI FTICR Mass Spectrometry

    SciTech Connect

    Shen, Yufeng ); Tolic, Nikola ); Zhao, Rui; Pasa Tolic, Ljiljana ); Li, Lingjun; Berger, Scott J.; Harkewicz, Richard ); Anderson, Gordon A. ); Belov, Mikhail E. ); Smith, Richard D. )

    2000-12-01

    We report on the design and application of a high-efficiency multiple-capillary liquid chromatography (LC) system for high-throughput proteome analysis. The multiple-capillary LC system was operated at the pressure of 10,000 psi using commercial LC pumps to deliver the mobile phase and newly developed passive feedback valves to switch the mobile phase flow and introduce samples. The multiple-capillary LC system was composed of several serially connected dual-capillary column devices. The dual-capillary column approach was designed to eliminate the time delay for regeneration (or equilibrium) of the capillary column after its use under the mobile phase gradient condition (i.e. one capillary column was used in separation and the other was washed using mobile phase A). The serially connected dual-capillary columns and ESI sources were operated independently, and could be used for either''backup'' operation or with other mass spectrometer(s). This high-efficiency multiple-capillary LC system uses switching valves for all operations and is highly amenable to automation. The separations efficiency of dual-capillary column device, optimal capillary dimensions (column length and packed particle size), suitable mobile phases for electrospray, and the capillary re-generation were investigated. A high magnetic field (11.5 tesla) Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was coupled on-line with this high-efficiency multiple-capillary LC system through an electrospray ionization source. The capillary LC provided a peak capacity of {approx}600, and the 2-D capillary LC-FTICR provided a combined resolving power of > 6 x 10 7 polypeptide isotopic distributions. For yeast cellular tryptic digests, > 100,000 polypeptides were typically detected, and {approx}1,000 proteins can be characterized in a single run.

  6. P39-T Analysis of Oligosaccharides by Capillary-Scale High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (CHPAEC-PAD) and On-Line Electrospray-Ionization Ion-Trap Mass Spectrometry (CHPAEC-ITMS)

    PubMed Central

    Bruggink, C.; Koeleman, C.; Barreto, V.; Lui, Y.; Pohl, C.; Ingendoh, A.; Wuhrer, M.; Hokke, C.; Deelder, A.

    2007-01-01

    High-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) is an established technique for selective separation and analysis of underivatized carbohydrates. The miniaturization of chromatographic techniques by means of capillary columns, and on-line coupling to mass spectrometry are critical to the further development of glycan analysis methods that are compatible with the current requirements in clinical settings. A system has been developed based on the Dionex BioLC equipped with a microbore gradient pump with PEEK flow splitter, a FAMOS micro autosampler, a modified electrochemical cell for on-line capillary PAD, and a capillary column (380 μm i.d.) packed with a new type of anion-exchange resin. This system operates with sensitivity in the low femtomol range. In addition, an on-line capillary desalter has been developed to allow direct coupling to the Bruker Esquire 3000 ion-trap mass spectrometer with electrospray ionization interface (ESI-IT-MS). Both systems have been evaluated using oligosaccharide standards as well as urine samples exhibiting various lysosomal oligosaccharide storage diseases. Initial data indicate that the robust and selective anion-exchange system, in combination with ESI-IT-MS for structure confirmation and analysis, provides a powerful platform that complements existing nano/capillary LC-MS methods for analytical determination of oligosaccharides in biological matrices.

  7. Fast filtration sampling protocol for mammalian suspension cells tailored for phosphometabolome profiling by capillary ion chromatography - tandem mass spectrometry.

    PubMed

    Kvitvang, Hans F N; Bruheim, Per

    2015-08-15

    Capillary ion chromatography (capIC) is the premium separation technology for low molecular phosphometabolites and nucleotides in biological extracts. Removal of excessive amounts of salt during sample preparation stages is a prerequisite to enable high quality capIC separation in combination with reproducible and sensitive MS detection. Existing sampling protocols for mammalian cells used for GC-MS and LC-MS metabolic profiling can therefore not be directly applied to capIC separations. Here, the development of a fast filtration sampling protocol for mammalian suspension cells tailored for quantitative profiling of the phosphometabolome on capIC-MS/MS is presented. The whole procedure from sampling the culture to transfer of filter to quenching and extraction solution takes less than 10s. To prevent leakage it is critical that a low vacuum pressure is applied, and satisfactorily reproducibility was only obtained by usage of a vacuum pressure controlling device. A vacuum of 60mbar was optimal for filtration of multiple myeloma Jjn-3 cell cultures through 5μm polyvinylidene (PVDF) filters. A quick deionized water (DI-water) rinse step prior to extraction was tested, and significantly higher metabolite yields were obtained during capIC-MS/MS analyses in this extract compared to extracts prepared by saline and reduced saline (25%) washing steps only. In addition, chromatographic performance was dramatically improved. Thus, it was verified that a quick DI-water rinse is tolerated by the cells and can be included as the final stage during filtration. Over 30 metabolites were quantitated in JJN-3 cell extracts by using the optimized sampling protocol with subsequent capIC-MS/MS analysis, and up to 2 million cells can be used in a single filtration step for the chosen filter and vacuum pressure. The technical set-up is also highly advantageous for microbial metabolome filtration protocols after optimization of vacuum pressure and washing solutions, and the reduced salt

  8. Analysis of methylene blue and its metabolites in blood by capillary electrophoresis/electrospray ionization mass spectrometry.

    PubMed

    Yang, Fang; Xia, Shifei; Liu, Zhencai; Chen, Jian; Lin, Yonghui; Qiu, Bin; Chen, Guonan

    2011-03-01

    A method for the determination of methylene blue (MB) and its metabolites (azure A, azure B and azure C) in rat blood by CE-electrospray ionization mass spectrometry (CE-ESI-MS) was developed in this paper. Different analytical parameters were investigated in detail such as pH and concentration of separation buffer, and ESI-MS instrumental parameters. Under the optimum conditions, MB and its metabolites were separated and detected in 27.3 min. LODs (defined as S/N=3) of this method were 0.22, 0.25, 0.10 and 0.30 μg/mL for MB, azure A, azure B and azure C, respectively. To get a satisfactory extraction efficiency of MB and its metabolites in rat blood, different extraction solutions were studied. By using this method, MB and its metabolites (azure A, azure B and azure C) were successfully analyzed in rat blood samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Profiling N-glycans of the egg jelly coat of the sea urchin Paracentrotus lividus by MALDI-TOF mass spectrometry and capillary liquid chromatography electrospray ionization-ion trap tandem mass spectrometry systems.

    PubMed

    Şahar, Umut; Deveci, Remziye

    2017-05-01

    Sea urchin eggs are surrounded by a carbohydrate-rich layer, termed the jelly coat, that consists of polysaccharides and glycoproteins. In the present study, we describe two mass spectrometric strategies to characterize the N-glycosylation of the Paracentrotus lividus egg jelly coat, which has an alecithal-type extracellular matrix like mammalian eggs. Egg jelly was isolated, lyophilized, and dialyzed, followed by peptide N-glycosidase F (PNGase-F) treatment to release N-glycans from their protein chain. These N-glycans were then derivatized by permethylation reaction, and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and capillary liquid chromatography electrospray ionization-ion trap tandem mass spectroscopy (CapLC ESI-Ion trap-MS/MS). N-glycans in the egg jelly coat glycoproteins were indicated by sodiated molecules at m/z 1579.8, 1783.9, 1988.0, 2192.0, and 2397.1 for permethylated oligosaccharides on MALDI-TOF MS. Fragmentation and structural characterization of these oligosaccharides were performed by ESI-Ion trap MS/MS. Then, MALDI-TOF-MS and ESI-Ion trap-MS/MS spectra were interpreted using the GlycoWorkbench software suite, a tool for building, displaying, and profiling glycan masses, to identify the original oligosaccharide structures. The oligosaccharides of the isolated egg jelly coat were mainly of the high mannose type. © 2017 Wiley Periodicals, Inc.

  10. A third-generation electro-kinetically pumped sheath flow nanospray interface with improved stability and sensitivity for automated capillary zone electrophoresis-mass spectrometry analysis of complex proteome digests

    PubMed Central

    Sun, Liangliang; Zhu, Guijie; Zhang, Zhenbin; Mou, Si; Dovichi, Norman J.

    2015-01-01

    We have reported a set of electrokinetically pumped sheath flow nanoelectrospray interfaces to couple capillary zone electrophoresis with mass spectrometry. A separation capillary is threaded through a cross into a glass emitter. A side arm provides fluidic contact with a sheath buffer reservoir that is connected to a power-supply. The potential applied to the sheath buffer drives electro-osmosis in the emitter to pump the sheath fluid at nanoliter/minute rates. Our first generation interface placed a flat-tipped capillary in the emitter. Sensitivity was inversely related to orifice size and to the distance from the capillary tip to the emitter orifice. A second generation interface used a capillary with an etched tip that allowed the capillary exit to approach within a few hundred micrometers of the emitter orifice, resulting in a significant increase in sensitivity. In both the first and second-generation interfaces, the emitter diameter was typically 8-μm; these narrow orifices were susceptible to plugging and tended to have limited lifetime. We now report a third-generation interface that employs a larger diameter emitter orifice with very short distance between the capillary tip and the emitter orifice. This modified interface is much more robust and produces much longer lifetime than our earlier designs with no loss in sensitivity. We evaluated the third-generation interface for a 5,000-min (127 runs, 3.5 days) repetitive analysis of bovine serum albumin digest using an uncoated capillary. We observed a 10% relative standard deviation in peak area, an average of 160,000 theoretical plates, and very low carry-over (much less than 1%). We employed a linear-polyacrylamide (LPA) coated capillary for single-shot, bottom-up proteomic analysis of 300 ng of Xenopus laevis fertilized egg proteome digest, and identified 1,249 protein groups and 4,038 peptides in a 110 min separation using an LTQ-Orbitrap Velos mass spectrometer; peak capacity was ~330. The proteome

  11. Analysis of cytokinin nucleotides in coconut (Cocos nucifera L.) water using capillary zone electrophoresis-tandem mass spectrometry after solid-phase extraction.

    PubMed

    Ge, Liya; Yong, Jean Wan Hong; Tan, Swee Ngin; Yang, Xin Hao; Ong, Eng Shi

    2006-11-10

    A method based on solid-phase extraction (SPE) and capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) is described for the separation and determination of six cytokinin nucleotides in coconut water. The best CZE separation for the six cytokinin nucleotide standards was achieved using a 25 mM ammonium formate/formic acid buffer (pH 3.8) and 2% (v/v) methanol with an applied gradient separation voltage (25 kV for 32 min, and then a linear gradient to 30 kV in 5 min, finally 30 kV to the end of separation) in less than 60 min. MS/MS with multiple reaction monitoring (MRM) detection was carried out to obtain sufficient selectivity and sensitivity for the cytokinin nucleotides. The combined use of on-line sample stacking and CZE-MS/MS achieved limits of detection (LODs) in the range of 0.06-0.19 microM for the six cytokinin nucleotides at a signal-to-noise ratio of 3. Furthermore, a novel dual-step SPE procedure was developed for the pre-concentration and purification of cytokinin nucleotides using Oasis HLB and Oasis MAX cartridges. The recoveries of the cytokinin nucleotides after the dual-step SPE were in the range of 44-71%. The combination of off-line SPE, on-line sample stacking and CZE-MS/MS approach was successfully applied to screen for endogenous cytokinin nucleotides present in coconut water sample. trans-Zeatin riboside-5'-monophosphate (ZMP) was detected and quantified in coconut water by CZE-MS/MS after SPE and on-line sample stacking.

  12. Alkylation of DNA by melphalan: investigation of capillary liquid chromatography-electrospray ionization tandem mass spectrometry in the study of the adducts at the nucleoside level.

    PubMed

    Van den Driessche, Bart; Lemière, Filip; Van Dongen, Walter; Esmans, Eddy L

    2003-02-25

    Nitrogen mustards are among the oldest cancer chemotherapeutic agents and remain the drugs of choice for treatment of many human cancers. A serious complication of treatment with nitrogen mustards is the increased risk of a secondary leukaemia in long-term survivors because not all alkylating agent interactions with DNA result in cell death. In an earlier study 2'-deoxy-5'-mononucleotide/melphalan adducts have been analysed by us by LC-ES MSMS. In this work we want to present the first results of the analysis of the corresponding 2'-deoxynucleoside/melphalan adducts from DNA hydrolysates by column switching/capillary LC-ES tandem mass spectrometry. Nucleosides, compared to nucleotides, give better chromatographic results and show a good sensitivity under electrospray (+) [ES(+)] ionisation. Several adducts were identified under ES(+) conditions. Mono-alkylated nucleoside adducts alkylated at the base moiety were identified for dGuo, dCyd and dAdo. Structures were identified by recording the low-energy CAD product ion scans. Also a mono-alkylated nucleotide pdA with alkylation position at the phosphate moiety could be detected. This proves that in the case of phosphate alkylation the enzymatic dephosphorylation reaction was inhibited. A Jurkat cell suspension was treated with melphalan (1 mM) and incubated at 37 degrees C (5% CO(2)). After 6 and 48 h, the DNA was isolated and enzymatically hydrolysed. The corresponding nucleoside pool was evaluated with the developed LC-MS method. In the 48-h experiment, one adduct could be identified as a N-7 alkylated dGuo. In the 6-h experiment, no adducts could be found. Additional experiments were done wherein Jurkat-DNA, isolated from a non-treated cell culture, was treated with melphalan. These results were analogous with the data found in melphalan-treated calf thymus DNA. Additionally, we tried to determine the exact alkylation position by interpreting high-resolution fragmentation spectra.

  13. Capillary electrophoresis-electrospray ionization mass spectrometry for rapid and sensitive N-glycan analysis of glycoproteins as 9-fluorenylmethyl derivatives.

    PubMed

    Nakano, Miyako; Higo, Daisuke; Arai, Etsuo; Nakagawa, Takatoshi; Kakehi, Kazuaki; Taniguchi, Naoyuki; Kondo, Akihiro

    2009-02-01

    It is well known that most protein therapeutics such as monoclonal antibody pharmaceuticals and other biopharmaceuticals including cancer biomarkers are glycoproteins, and thus the development of high-throughput and sensitive analytical methods for glycans is essential in terms of their determination and quality control. We previously reported a novel alternative labeling method for glycans involving 9-fluorenylmethyl chloroformate (Fmoc-Cl) instead of the conventional reductive amination procedure. The derivatives were analyzed by high-performance liquid chromatography (HPLC) (Kamoda S, Nakano M, Ishikawa R, Suzuki S, Kakehi K. 2005. Rapid and sensitive screening of N-glycans as 9-fluorenylmethyl derivatives by high-performance liquid chromatography: A method which can recover free oligosaccharides after analysis. J Proteome Res. 4:146-152). This method was rapid and simple; however, it was time-consuming in terms of analysis by HPLC and did not provide so much information such as the detailed structures and mass numbers of glycans. Here we have developed a high-throughput and highly sensitive method. It comprises three steps, i.e., release of glycans, derivatization with Fmoc, and capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI MS) analysis. We analyzed several glycoproteins such as fetuin, alpha1 acid glycoprotein, IgG, and transferrin in order to validate this method. We were able to analyze the above glycoproteins with the three-step procedure within only 5 h, which provided detailed N-glycan patterns. Moreover, the MS/MS analysis allowed identification of the N-glycan structures. As novel applications, the method was employed for the analysis of N-glycans derived from monoclonal antibody pharmaceuticals and also from alpha-fetoprotein; the latter is known as one of the tumor markers of hepatocellular carcinomas. We were able to easily and rapidly determine the detailed structures of the N-glycans. The present method is very useful

  14. Capillary electrophoresis coupled to mass spectrometry for the determination of anthelmintic benzimidazoles in eggs using a QuEChERS with preconcentration as sample treatment.

    PubMed

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

    2013-02-22

    Benzimidazoles (BZDs) are anthelmintic agents widely used in veterinary medicine. Their use in food-producing animals increases the possibility of residues appearing in animal tissues and products. Most analytical procedures reported for the determination of BZDs have been developed based on liquid chromatography (LC) because of their polar nature - zwitterionic - and thermal lability. To our knowledge, the determination of these compounds by capillary electrophoresis coupled to mass spectrometry (CE-MS) has not yet been described. In this work CE-MS is proposed for the identification and simultaneous quantification of several benzimidazoles in egg samples. The target compounds were 2-aminobenzimidazole, carbendazim, albendazole-2-aminosulphone, 5-hydroxy-thiabendazole, oxibendazole, albendazole, fenbendazole, oxfendazole, albendazole-sulphone, fenbendazole-sulphone. Optimization of the composition and nature - organic/aqueous - of both the electrophoretic separation buffer and the injection medium was carried out with a view to obtaining the best sensitivity and separation efficiency for the CE-MS coupling. A comparative study was carried out on different sample treatments for analyte extraction from egg samples. Two of them comprised a solvent extraction step followed by clean-up using a new commercial polymeric sorbent (Evolute ABN(©)), and the third was a particularization of the general extractive method so called Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS). Different modifications of the QuEChERS method were assayed, which included a later preconcentration step based on either SPE with MCX(©) sorbents or evaporation. The whole optimized method (QuEChERS with preconcentration prior to CE-MS) was validated according to the 2002/657/EC decision obtaining a CE-MS method sufficiently reliable and robust to determine residues of these compounds in egg samples of different origins with limits of detection between 3 and 51 μgL(-1) (S/N=3) and

  15. In vivo biotransformation of 17 alpha-methyltestosterone in the horse revisited: identification of 17-hydroxymethyl metabolites in equine urine by capillary gas chromatography/mass spectrometry.

    PubMed

    Dumasia, M C

    2003-01-01

    The in vivo phase I biotransformation of 17 alpha-methyltestosterone in the horse leads to the formation of a complex mixture of regio- and stereoisomeric C(20)O(2), C(20)O(3) and C(20)O(4) metabolites, excreted in urine as glucuronide and sulphate phase II conjugates. The major pathways of in vivo metabolism are the reduction of the A-ring (di- and tetrahydro), epimerisation at C-17 and oxidations mainly at C-6 and C-16. Some phase I metabolites have been identified previously by positive ion electron ionisation capillary gas chromatography/mass spectrometry (GC/EI + MS) mainly from the characteristic fragmentation patterns of their methyloxime-trimethylsilyl ether (MO-TMS), enol-TMS or TMS ether derivatives. Following oral administration of 17 alpha-methyltestosterone to two castrated thoroughbred male horses, the glucuronic acid conjugates excreted in post-administration urine samples were selectively hydrolysed by E. coli beta-glucuronidase enzymes. Unconjugated metabolites and the steroid aglycones obtained after enzymatic deconjugation were isolated from urine by solid-phase extraction, derivatised as MO-TMS ethers and analysed by GC/EI + MS. In addition to some of the known metabolites previously identified from the characteristic mass spectral fragmentation patterns of 17 alpha-methyl steroids, some isobaric compounds exhibiting a diagnostic loss of 103 mass units from the molecular ions with subsequent losses of trimethylsilanol or methoxy groups and an absence of the classical D-ring fragment ion were detected. From an interpretation of their mass spectra, these compounds were identified as 17-hydroxymethyl metabolites, formed in vivo in the horse by oxidation of the 17-methyl moiety of 17 alpha-methyltestosterone. This study reports on the GC/EI + MS identification of these novel 17-hydroxymethyl C(20)O(3) and C(20)O(4) metabolites of 17 alpha-methyltestosterone excreted in thoroughbred horse urine.

  16. Efficient interface for online coupling of capillary electrophoresis with inductively coupled plasma-mass spectrometry and its application in simultaneous speciation analysis of arsenic and selenium.

    PubMed

    Liu, Lihong; Yun, Zhaojun; He, Bin; Jiang, Guibin

    2014-08-19

    A simple and highly efficient online system coupling of capillary electrophoresis to inductively coupled plasma-mass spectrometry (CE-ICP-MS) for simultaneous separation and determination of arsenic and selenium compounds was developed. CE was coupled to an ICP-MS system by a sprayer with a novel direct-injection high-efficiency nebulizer (DIHEN) chamber as the interface. By using this interface, six arsenic species, including arsenite (As(III), arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), and arsenocholine (AsC) and five selenium species (such as sodium selenite (Se(IV)), sodium selenate (Se(VI)), selenocysteine (SeCys), selenomethionine (SeMet), and Se-methylselenocysteine (MeSeCys)) were baseline-separated and determined in a single run within 9 min under the optimized conditions. Minimum dead volume, low and steady sheath flow liquid, high nebulization efficiency, and high sample transport efficiency were obtained by using this interface. Detection limits were in the range of 0.11-0.37 μg L(-1) for the six arsenic compounds (determined as (75)As at m/z 75) and 1.33-2.31 μg L(-1) for the five selenium species (determined as (82)Se at m/z 82). Repeatability expressed as the relative standard deviations (RSD, n = 6) of both migration time and peak area were better than 2.68% for arsenic compounds and 3.28% for selenium compounds, respectively. The proposed method had been successfully applied for the determination of arsenic and selenium species in the certified reference materials DORM-3, water, urine, and fish samples.

  17. Capillary electrophoresis-mass spectrometry for direct determination of urinary modified nucleosides. Evaluation of synthetic urine as a surrogate matrix for quantitative analysis.

    PubMed

    Rodríguez-Gonzalo, Encarnación; Hernández-Prieto, Raquel; García-Gómez, Diego; Carabias-Martínez, Rita

    2013-12-30

    This work describes the development of a fast and reliable method based on capillary zone electrophoresis coupled with electrospray ionization-mass spectrometry (CZE-ESI-MS) for the determination of modified nucleosides in untreated human urine. The target compounds were guanine, 1-methyl-guanine, 7-methyl-guanine, 9-methyl-guanine, adenosine, 1-methyl-adenosine, cytidine, guanosine, 7-methyl-guanosine. As internal standards, ribose-2-(13)C-adenosine and 8-(13)C-guanine were used. The CZE separation was carried out in acidic medium (pH 2.5). MS detection with a single quadrupole, with ESI operating in positive-ion mode, was optimized. For the analysis of urine samples, owing to the endogenous character of these analytes different quantification strategies were explored. The standard additions method, matrix-matched calibration in synthetic urine and calibration in pure aqueous medium were compared in order to evaluate the endogenous levels of these compounds in human urine. The results obtained showed that calibration in synthetic urine as a surrogate matrix was an appropriate alternative to the method of standard additions for the accurate quantitation of compounds such as guanine, 1-methyl-guanine, 7-methyl-guanine, adenosine, 1-methyl-adenosine and cytidine by CE-ESI-MS directly in the urine matrix; values in the range 0.1μg/mL for cytidine and 6.4μg/mL for 7mGua, as the lowest and the highest level, were found in untreated urine from healthy volunteers. These results were confirmed by LC-MS/MS detection. It can be concluded that the electrophoretic CZE-ESI-MS methodology offers a valid and reliable alternative for the determination of urinary nucleosides at naturally occurring levels in healthy individuals. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Coupling of metal-organic frameworks-containing monolithic capillary-based selective enrichment with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry for efficient analysis of protein phosphorylation.

    PubMed

    Li, Daojin; Yin, Danyang; Chen, Yang; Liu, Zhen

    2017-05-19

    Protein phosphorylation is a major post-translational modification, which plays a vital role in cellular signaling of numerous biological processes. Mass spectrometry (MS) has been an essential tool for the analysis of protein phosphorylation, for which it is a key step to selectively enrich phosphopeptides from complex biological samples. In this study, metal-organic frameworks (MOFs)-based monolithic capillary has been successfully prepared as an effective sorbent for the selective enrichment of phosphopeptides and has been off-line coupled with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for efficient analysis of phosphopeptides. Using š-casein as a representative phosphoprotein, efficient phosphorylation analysis by this off-line platform was verified. Phosphorylation analysis of a nonfat milk sample was also demonstrated. Through introducing large surface areas and highly ordered pores of MOFs into monolithic column, the MOFs-based monolithic capillary exhibited several significant advantages, such as excellent selectivity toward phosphopeptides, superb tolerance to interference and simple operation procedure. Because of these highly desirable properties, the MOFs-based monolithic capillary could be a useful tool for protein phosphorylation analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. A minimal-invasive method for systemic bio-monitoring of the environmental pollutant phenanthrene in humans: Thermal extraction and gas chromatography - mass spectrometry from 1 mL capillary blood.

    PubMed

    Gruber, Beate; Schneider, Julian; Föhlinger, Michael; Buters, Jeroen; Zimmermann, Ralf; Matuschek, Georg

    2017-03-03

    Phenanthrene is present in numerous environmental media and serves as a model substrate for the biomonitoring of polycyclic aromatic hydrocarbon (PAH). PAH exposure studies are commonly focused on urinary metabolites, concentrations of which are dependent on absorption, biotransformation and excretion. Monitoring of unmetabolized PAHs in blood would allow more reliable exposure assessment, but requires invasive sampling and extensive sample preparation. We describe the analysis of phenanthrene in 1μL capillary blood using thermal extraction (TE) combined with gas chromatography - mass spectrometry (GC-MS). Less invasive sampling of 1μL capillary blood does not require the assistance of medical staff. Compared to previous studies, analysis time was improved significantly by TE due to minimization of sample preparation steps. The evaluate method was applied successfully to the monitoring of phenanthrene blood levels. This is the first report presenting the pharmacokinetics of unmetabolized PAHs in human.

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

    PubMed

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

    2012-03-10

    Capillary electrophoresis coupled to time-of-flight mass spectrometry was used in the present work for the determination of therapeutic and abused drugs and their metabolites in the hair of subjects undergoing addiction treatments, in order to monitor their compliance to therapy. For this purpose a rapid, qualitative drug screening method was adopted based on capillary electrophoresis hyphenated with time-of-flight mass spectrometry, which had earlier been developed and validated for the forensic-toxicological analysis of hair, limitedly to illicit/abused drugs [1]. Sampling of hair was carried out in order to refer to a time window of about two months from the date of sampling (i.e. 2cm ca. from cortex). A single extraction procedure was applied, allowing the determination in the hair matrix of "drugs of abuse" referred to the past abuses, and therapeutic drugs prescribed in the detoxification program as well as their metabolites. Analyte identification was based on accurate mass measurements and comparison of isotope patterns, providing the most likely matching between accurate mass value and elemental formula. Small molecules (<500Da) of forensic and toxicological interest could be identified unambiguously using mass spectrometric conditions tailored to meet a mass accuracy ≤5ppm. In the present study, the proposed approach proved suitable for the rapid broad spectrum screening of hair samples, although needing further confirmation of results by using fragmentation mass spectrometry.

  1. 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

  2. Pressure-assisted introduction of urine samples into a short capillary for electrophoretic separation with contactless conductivity and UV spectrometry detection.

    PubMed

    Makrlíková, Anna; Opekar, František; Tůma, Petr

    2015-08-01

    A computer-controlled hydrodynamic sample introduction method has been proposed for short-capillary electrophoresis. In the method, the BGE flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. A short pressure impulse is generated in the electrolyte stream at the time when the sample zone is at the capillary, leading to injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. This way of sample introduction does not involve movement of the capillary and both of its ends remain constantly in the solution during both sample injection and separation. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. The new sample introduction method was tested in the determination of ammonia, creatinine, uric acid, and hippuric acid in human urine. The determination was performed in a capillary with an overall length of 10.5 cm, in two BGEs with compositions 50 mM MES + 5 mM NaOH (pH 5.1) and 1 M acetic acid + 1.5 mM crown ether 18-crown-6 (pH 2.4). A dual contactless conductivity/UV spectrometric detector was used for the detection.

  3. Separation and identification of peptides from gel-isolated membrane proteins using a microfabricated device for combined capillary electrophoresis/nanoelectrospray mass spectrometry.

    PubMed

    Li, J; Kelly, J F; Chernushevich, I; Harrison, D J; Thibault, P

    2000-02-01

    The coupling of microfabricated devices to nanoelectrospray mass spectrometers using both a triple quadrupole and a quadrupole time-of-flight mass spectrometer (QqTOF MS) is presented for the analysis of trace-level membrane proteins. Short disposable nanoelectrospray emitters were directly coupled to the chip device via a low dead volume connection. The analytical performance of this integrated device in terms of sensitivity and reproducibility was evaluated for standard peptide mixtures. A concentration detection limit ranging from 3.2 to 43.5 nM for different peptides was achieved in selected ion monitoring, thus representing a 10-fold improvement in sensitivity compared to that of microelectrospray using the same chip/mass spectrometer. Replicate injections indicated that reproducibility of migration time was typically less than 3.1% RSD whereas RSD values of 6-13% were observed on peak areas. Although complete resolution of individual components is not typically achieved for complex digests, the present chip capillary electrophoresis (chip-CE) device enabled proper sample cleanup and partial separation of multicomponent samples prior to mass spectral identification. Analyses of protein digests were typically achieved in less than 1.5 min with peak widths of 1.8-2.5 s (half-height definition) as indicated from individual reconstructed ion electropherograms. The application of this chip-CE/QqTOF MS system is further demonstrated for the identification of membrane proteins which form a subset of the Haemophilus influenzae proteome. Bands first separated by 1D-gel electrophoresis were excised and digested, and extracted tryptic peptides were loaded on the chip without any further sample cleanup or on-line adsorption preconcentration. Accurate molecular mass determination (< 5 ppm) in peptide-mapping experiments was obtained by introducing an internal standard via a postseparation channel. The analytical potential of this integrated device for the identification of

  4. Selenium speciation using capillary electrophoresis coupled with modified electrothermal atomic absorption spectrometry after selective extraction with 5-sulfosalicylic acid functionalized magnetic nanoparticles.

    PubMed

    Yan, Lizhen; Deng, Biyang; Shen, Caiying; Long, Chanjuan; Deng, Qiufen; Tao, Chunyao

    2015-05-22

    A new method for selenium speciation in fermented bean curd wastewater and juice was described. This method involved sample extraction with 5-sulfosalicylic acid (SSA)-functionalized silica-coated magnetic nanoparticles (SMNPs), capillary electrophoresis (CE) separation, and online detection with a modified electrothermal atomic absorption spectrometry (ETAAS) system. The modified interface for ETAAS allowed for the introduction of CE effluent directly through the end of the graphite tube. Elimination of the upper injection hole of the graphite tube reduced the loss of the anlayte and enhanced the detection sensitivity. The SSA-SMNPs were synthesized and used to extract trace amounts of selenite [Se(IV)], selenite [Se(VI)], selenomethionine (SeMet), and selenocystine (SeCys2) from dilute samples. The concentration enrichment factors for Se(VI), Se(IV), SeMet, and SeCys2 were 21, 29, 18, and 12, respectively, using the SSA-SMNPs extraction. The limits of detection for Se(VI), Se(IV), SeMet, and SeCys2 were 0.18, 0.17, 0.54, 0.49ngmL(-1), respectively. The RSD values (n=6) of method for intraday were observed between 0.7% and 2.9%. The RSD values of method for interday were less than 3.5%. The linear range of Se(VI) and Se(IV) were in the range of 0.5-200ngmL(-1), and the linear ranges of SeMet and SeCys2 were 2-500 and 2-1000ngmL(-1), respectively. The detection limits of this method were improved by 10 times due to the enrichment by the SSA-SMNP extraction. The contents of Se(VI) and Se(IV) in fermented bean curd wastewater were measured as 3.83 and 2.62ngmL(-1), respectively. The contents of Se(VI), Se(IV), SeMet, and SeCys2 in fermented bean curd juice were determined as 6.39, 4.08, 2.77, and 4.00ngmL(-1), respectively. The recoveries were in the range of 99.14-104.5% and the RSDs (n=6) of recoveries between 0.82% and 3.5%. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Online capillary solid-phase microextraction coupled liquid chromatography-mass spectrometry for analysis of chiral secondary alcohol products in yeast catalyzed stereoselective reduction cell culture.

    PubMed

    Cheng, Cheanyeh; Nian, Yu-Chuan

    2015-02-06

    An online solid-phase microextraction coupled liquid chromatography-electrospray ionization-ion trap mass spectrometry was developed for the analysis of trace R- and S-4-phenyl-2-butanol (R- and S-pbol) in salt rich cell culture of Saccharomyces cerevisiae catalyzed stereoselective reduction of 4-pheny-2-butanone (pbone). A Supel-Q PLOT capillary column was used for the extraction and deionized distilled water was used as the extraction mobile phase. The extraction flow rate and extraction time were at 0.1 mL min(-1) and 0.95 min, respectively. The three target analytes, pbone, R-pbol, and S-4-pbol, were desorbed and eluted by the mobile phase of water/methanol/isopropanol (55/25/20, v/v/v) with a flow rate of 0.5 mL min(-1) and analyzed by a chiral column. The mass spectrometric detection of the three target analytes was in positive ion mode with the signal [M+Na](+). The matrix-matched external standard calibration curves with linear concentration range between 0 and 50 μg mL(-1) were used for quantitative analysis. The linear regression correlation coefficients (r(2)) of the standard calibration curves were between 0.9950 and 0.9961. The yeast mediated reduction was performed with a recation culture of yeast incubation culture/glycerol (70/30, v/v) for 4 days. This biotransformation possessed 82.3% yield and 92.9% S-enantomeric excess. The limit of detection (LOD)/limit of quantification (LOQ) for pbone, R-pbol, and S-pbol was 0.02/0.067, 0.01/0.033, and 0.01/0.033 μg mL(-1), respectively. The intra-day and inter-day precisions from repeated measurements were 10.8-21.1% and 11.6-18.7%, respectively. The analysis accuracy from spike recovery was 84-91%.

  6. Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry

    USGS Publications Warehouse

    Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.

    2006-01-01

    A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance

  7. Optimization of the hyphenation between capillary zone electrophoresis and inductively coupled plasma mass spectrometry for the measurement of As-, Sb-, Se- and Te-species, applicable to soil extracts

    NASA Astrophysics Data System (ADS)

    Casiot, Corinne; Donard, Olivier F. X.; Potin-Gautier, Martine

    2002-01-01

    The optimization of the hyphenation between capillary zone electrophoresis (CZE) and inductively coupled plasma mass spectrometry (ICP-MS) was studied for the simultaneous determination of metalloid species in the environment. Arsenic (arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid), selenium (selenite, selenate, selenomethionine, selenocystine), antimony (antimonate) and tellurium (tellurite, tellurate) species were simultaneously separated using a 75-μm i.d. fused silica capillary using either a chromate or a phosphate electrolyte. Different nebulizers were tested for introduction in the detector. A V-groove nebulizer (the Babington) and two concentric micronebulizers (the MCN-100 and the MicroMist) were studied in order to improve resolution, sensitivity and reproducibility. The optimization of CE-ICP-MS interface operating parameters is discussed for each nebulizer-interface combination, and special attention is given to the position of the capillary inside the nebulizer. Different nebulizer gas and liquid sheath flow rates were studied in detail and they hardly affect electrophoretic resolution and peak width. The best analytical performance characteristics were obtained with the MicroMist nebulizer. Detection limits with this nebulizer were found to range between 6 and 58 μg l -1 depending on the species investigated using pressure injection and below 1 μg l -1 for most of the species with electromigrative injection. Analysis of soil extracts showed that it was possible to carry out this technique on real samples.

  8. Selective on-line serum peptide extraction and multidimensional separation by coupling a restricted-access material-based capillary trap column with nanoliquid chromatography-tandem mass spectrometry.

    PubMed

    Hu, Lianghai; Boos, Karl-Siegfried; Ye, Mingliang; Wu, Ren'an; Zou, Hanfa

    2009-07-10

    As the serum peptidome gets increasing attention for biomarker discovery, one of the important issues is how to efficiently extract the peptides from highly complex human serum for peptidome analysis. Here we developed a fully automated platform for direct injection, on-line extraction, multidimensional separation and MS detection of peptides present in human serum. A capillary SPE column packed with a novel mix mode restricted access material (RAM) exhibiting strong cation exchange and size exclusion chromatography (SCX/SEC) properties were coupled with a nanoliquid chromatography-mass spectrometry (nanoLC-MS) system. The capillary SPE column excludes the high abundant serum proteins such as HSA by size exclusion chromatography and simultaneously extracts the low molecular weight peptides by binding to sulfonic acid residues. Subsequently, the trapped peptides are eluted to a capillary LC column packed with a RP-C18 stationary phase. After injection of only 2 microL human serum to the one-dimensional nanoLC-MS system around 400 peptides could be identified. When conducting a multidimensional separation, the described SCX/SEC/RP-MS platform allows the separation and identification of 1286 peptides present in human serum by the injection and on-line processing of 20 microL human serum sample.

  9. Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory - determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

    USGS Publications Warehouse

    Sandstrom, Mark W.; Wydoski, Duane S.; Schroeder, Michael P.; Zamboni, Jana L.; Foreman, William T.

    1992-01-01

    A method for the isolation of organonitrogen herbicides from natural water samples using solid-phase extraction and analysis by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction cartridges containing octadecyl-bonded porous silica to remove the herbicides. The cartridges are dried using carbon dioxide, and adsorbed herbicides are removed from the cartridges by elution with 1.8 milliliters of hexaneisopropanol (3:1). Extracts of the eluants are analyzed by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring of at least three characteristic ions. The method detection limits are dependent on sample matrix and each particular herbicide. The method detection limits, based on a 100-milliliter sample size, range from 0.02 to 0.25 microgram per liter. Recoveries averaged 80 to 115 percent for the 23 herbicides and 2 metabolites in 1 reagent-water and 2 natural-water samples fortified at levels of 0.2 and 2.0 micrograms per liter.

  10. Novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane-silica monolithic capillary microextraction and its application to the fractionation of aluminum in rainwater and fruit juice by electrothermal vaporization inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Zheng, Fei; Hu, Bin

    2008-01-01

    A novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS)-silica monolithic capillary was prepared by sol-gel technology, and used as capillary microextraction (CME) column for aluminum fractionation by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV)-ICP-MS with the use of polytetrafluoroethylene (PTFE) slurry as fluorinating agent. The extraction behaviors of different Al species were studied and it was found that in the pH range of 4-7, labile monomeric Al (free Al 3+, Al-OH and Al-F) could be retained quantitatively on the monolithic capillary, while non-labile monomeric Al (Al-Cit and Al-EDTA) passed through the capillary directly. The labile monomeric Al retained on monolithic capillary was eluted with 10 μL 1 mol L - 1 HCl and the elution was introduced into the ETV for fluorination assisted ETV-ICP-MS determination. The total monomeric Al fraction was also determined by AAPTS-silica monolithic CME-fluorination-assisted electrothermal vaporization (FETV)-ICP-MS after the sample solution was adjusted to pH 8.8. Non-labile monomeric Al was obtained by subtracting labile monomeric Al from the total monomeric Al. Under the optimized conditions, the relative standard deviation (R.S.D) was 6.2% ( C = 1 μg L - 1 , n = 7; sample volume, 5 mL), and the limit of detection was 1.6 ng L - 1 for Al with an enrichment factor of 436 fold and a sampling frequency of 9 h - 1 . The prepared AAPTS-silica monolithic capillary showed an excellent pH tolerance and solvent stability and could be used for more than 250 times without decreasing adsorption efficiency. The developed method was applied to the fraction of Al in rainwater and fruit juice, and the results demonstrated that the established system had advantages over the existing 8-hydroxyquinoline (8-HQ) chelating system for Al fractionation such as wider pH range, higher tolerance of interference and better regeneration.

  11. Analysis of bovine milk caseins on organic monolithic columns: an integrated capillary liquid chromatography-high resolution mass spectrometry approach for the study of time-dependent casein degradation.

    PubMed

    Pierri, Giuseppe; Kotoni, Dorina; Simone, Patrizia; Villani, Claudio; Pepe, Giacomo; Campiglia, Pietro; Dugo, Paola; Gasparrini, Francesco

    2013-10-25

    Casein proteins constitute approximately 80% of the proteins present in bovine milk and account for many of its nutritional and technological properties. The analysis of the casein fraction in commercially available pasteurized milk and the study of its time-dependent degradation is of considerable interest in the agro-food industry. Here we present new analytical methods for the study of caseins in fresh and expired bovine milk, based on the use of lab-made capillary organic monolithic columns. An integrated capillary high performance liquid chromatography and high-resolution mass spectrometry (Cap-LC-HRMS) approach was developed, exploiting the excellent resolution, permeability and biocompatibility of organic monoliths, which is easily adaptable to the analysis of intact proteins. The resolution obtained on the lab-made Protein-Cap-RP-Lauryl-γ-Monolithic column (270 mm × 0.250 mm length × internal diameter, L × I.D.) in the analysis of commercial standard caseins (αS-CN, β-CN and κ-CN) through Cap-HPLC-UV was compared to the one observe using two packed capillary C4 columns, the ACE C4 (3 μm, 150 mm × 0.300 mm, L × I.D.) and the Jupiter C4 column (5 μm, 150 mm × 0.300 mm, L × I.D.). Thanks to the higher resolution observed, the monolithic capillary column was chosen for the successive degradation studies of casein fractions extracted from bovine milk 1-4 weeks after expiry date. The comparison of the UV chromatographic profiles of skim, semi-skim and whole milk showed a major stability of whole milk towards time-dependent degradation of caseins, which was further sustained by high-resolution analysis on a 50-cm long monolithic column using a 120-min time gradient. Contemporarily, the exact monoisotopic and average molecular masses of intact αS-CN and β-CN protein standards were obtained through high resolution mass spectrometry and used for casein identification in Cap-LC-HRMS analysis. Finally, the proteolytic degradation of β-CN in skim milk

  12. EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)

    EPA Science Inventory

    Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water.

  13. EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)

    EPA Science Inventory

    Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water.

  14. Automation of nanoflow liquid chromatography-tandem mass spectrometry for proteome and peptide profiling analysis by using a monolithic analytical capillary column.

    PubMed

    Jiang, Xiaogang; Dong, Jing; Wang, Fangjun; Feng, Shun; Ye, Mingliang; Zou, Hanfa

    2008-04-01

    An automated nano-LC-MS/MS platform without trap column was established, which only used a 20 cm lauryl methacrylate-ethylene dimethacrylate (LMA-EDMA) monolithic capillary column to allow preconcentration and separation of peptides. The monolithic column had the advantages of good permeability and low backpressure resulting in higher flow rates for capillary columns. Tryptic digests of bovine albumin and yeast protein extract were tested using the monolithic column system. High proteomic coverage using this approach were demonstrated in this study. Furthermore, peptide samples extracted from mouse liver were separated by using the monolithic column system combined with size-exclusion chromatography prefractionation. This monolithic column system might be a promising alternative for the automated system previously using a trap column for routine proteome and peptide profiling analysis.

  15. Capillary-induced Homogenization of Matrix in Paper: A Powerful Approach for the Quantification of Active Pharmaceutical Ingredients Using Mass Spectrometry Imaging

    NASA Astrophysics Data System (ADS)

    de Menezes, Maico; de Oliveira, Diogo Noin; Catharino, Rodrigo Ramos

    2016-07-01

    Herein we present a novel approach for the quantification of active pharmaceutical ingredients (APIs) using mass spectrometry imaging. This strategy uses a filter paper previously “eluted” with a MALDI matrix solution as a support for analyte application. Samples are submitted to mass spectrometry imaging (MSI) and quantification through characteristic fingerprints is ultimately performed. Results for the content of rosuvastatin from a known formulation are comparable to those obtained with a validated HPLC method.

  16. Capillary-induced Homogenization of Matrix in Paper: A Powerful Approach for the Quantification of Active Pharmaceutical Ingredients Using Mass Spectrometry Imaging

    PubMed Central

    de Menezes, Maico; de Oliveira, Diogo Noin; Catharino, Rodrigo Ramos

    2016-01-01

    Herein we present a novel approach for the quantification of active pharmaceutical ingredients (APIs) using mass spectrometry imaging. This strategy uses a filter paper previously “eluted” with a MALDI matrix solution as a support for analyte application. Samples are submitted to mass spectrometry imaging (MSI) and quantification through characteristic fingerprints is ultimately performed. Results for the content of rosuvastatin from a known formulation are comparable to those obtained with a validated HPLC method. PMID:27439589

  17. Separation and quantitation of milk whey proteins of close isoelectric points by on-line capillary isoelectric focusing--electrospray ionization mass spectrometry in glycerol-water media.

    PubMed

    Lecoeur, Marie; Gareil, Pierre; Varenne, Anne

    2010-11-12

    On-line coupling between CIEF and ESI/MS based on the use of bare fused-silica capillaries and glycerol-water media, recently developed in our laboratory, has been investigated for the separation of milk whey proteins that present close pI values. First, a new rinsing procedure, compatible with MS detection, has been developed to desorb these rather hydrophobic proteins (α-casein (α-CN), bovine serum albumin (BSA), lactoferrin (LF)) from the inner capillary wall and to avoid capillary blockages. Common hydrochloric acid washing solution was replaced by a multi-step sequence based on the use of TFA, ammonia and ethanol. To achieve the separation of major whey proteins (β-lactoglobulin A (β-LG A), β-lactoglobulin B (β-LG B), α-lactalbumin (α-LA) and BSA, which possess close pI values (4.5-5.35), CIEF parameters i.e. carrier ampholyte nature, capillary partial filling length with ampholyte/protein mixture and focusing time, have been optimized with respect to total analysis time, sensitivity and precision on pI determination. After optimization of sheath liquid composition (80:20 (v/v) methanol-water+1% HCOOH), quantitation of β-LG A, β-LG B, α-LA and BSA was performed. The limits of detection obtained from extracted ion current (EIC) and single ion monitoring (SIM) modes were in the 57-136 nM and 11-68 nM range, respectively. Finally, first results obtained from biological samples demonstrated the suitability of CIEF-MS as a potential alternative methodology to 2D-PAGE to diagnose milk protein allergies.

  18. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry.

    PubMed

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

    2015-06-01

    A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1×10(-7) M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10(-5) M angiotensin II. The system was also applied to the analysis of a 10(-4) mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10(-3) mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry

    PubMed Central

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing

    2015-01-01

    A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1-cm long SCX-SPE monolith, a 60-cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1 × 10−7 M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N = 44 000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10−5 M angiotensin II. The system was also applied to the analysis of a 10−4 mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10−3 mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates. PMID:25863379

  20. Online Capillary IsoElectric Focusing-ElectroSpray Ionization Mass Spectrometry (CIEF-ESI MS) in Glycerol-Water Media for the Separation and Characterization of Hydrophilic and Hydrophobic Proteins.

    PubMed

    Mokaddem, Meriem; d'Orlyé, Fanny; Varenne, Anne

    2016-01-01

    Capillary isoelectric focusing (CIEF) is a high-resolution technique for the separation of ampholytes, such as proteins, according to their isoelectric point. CIEF coupled online with MS is regarded as a promising alternative to 2-D PAGE for fast proteome analysis with high-resolving capabilities and enhanced structural information without the drawbacks of conventional slab-gel electrophoresis. However, online coupling has been rarely described, as it presents some difficulties. A new methodology for the online coupling of CIEF with electrospray ionization mass spectrometry (ESI-MS) has been developed in glycerol-water media. This new integrated methodology provides a mean for the characterization of a large number of hydrophilic and hydrophobic proteins.

  1. Capillary-channeled polymer (C-CP) films as processing platforms for protein analysis by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS).

    PubMed

    Pittman, Jennifer J; Manard, Benjamin T; Kowalski, Paul J; Marcus, R Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H(2)O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs.

  2. Capillary-Channeled Polymer (C-CP) Films as Processing Platforms for Protein Analysis by Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry (MALDI-MS)

    NASA Astrophysics Data System (ADS)

    Pittman, Jennifer J.; Manard, Benjamin T.; Kowalski, Paul J.; Marcus, R. Kenneth

    2012-01-01

    Polypropylene (PP) capillary-channeled polymer (C-CP) films have parallel, μm-sized channels that induce solution wicking via capillary action. Efficient mass transport from the solution phase to the channel surface leads to adsorption of hydrophobic protein solutes. The basic premise by which C-CP films can be used as media to manipulate analyte solutions (e.g., proteins in buffer), for the purpose of desalting or chromatographic separation prior to MALDI-MS analysis is presented here. Cytochrome c and myoglobin prepared in a Tris-HCl buffer, and ribonuclease A, lysozyme, and transferrin prepared in phosphate buffered saline (PBS), are used as the test solutions to demonstrate the desalting concept. Protein analysis is performed after deposition on a C-CP film with and without a water washing step, followed by spray deposition of a typical sinapinic acid matrix. Extracted MALDI mass spectra exhibit much improved signal-to-noise characteristics after water washing. A mixture of cytochrome c and myoglobin (2 μL of 2.5 μM each in Tris-HCl buffer) was applied, washed with water and spatially separated via simple capillary action (wicking) using a reversed-phase solvent composition of 0.1% trifluoroacetic acid (TFA) in 50:50 acetonitrile (ACN):H2O. Subsequent application of sinapinic acid followed by imaging of the film using MALDI-MS reveals that as the protein solution is wicked down the film, separation occurs.

  3. Membrane-assisted capillary isoelectric focusing coupling with matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry for neuropeptide analysis

    PubMed Central

    Zhang, Zichuan; Wang, Junhua; Hui, Limei; Li, Lingjun

    2011-01-01

    Herein we report a highly efficient and reliable membrane-assisted capillary isoelectric focusing (MA-CIEF) system being coupled with MALDI-FTMS for the analysis of complex neuropeptide mixtures. The new interface consists of two membrane-coated joints made near each end of the capillary for applying high voltage, while the capillary ends were placed in the two reservoirs which were filled with anolyte (acid) and catholyte (base) to provide pH difference. Optimizations of CIEF conditions and comparison with conventional CIEF were carried out by using bovine serum albumin (BSA) tryptic peptides. It was shown that the MA-CIEF could provide more efficient, reliable and faster separation with improved sequence coverage when coupled to MALDI-FTMS. Analyses of orcokinin family neuropeptides from crabs Cancer borealis and Callinectes sapidus brain extracts have been conducted using the established MA-CIEF/MALDI-FTMS platform. Increased number of neuropeptides was observed with significantly enhanced MS signal in comparison with direct analysis by MALDI FTMS. The results highlighted the potential of MA-CIEF as an efficient fractionation tool for coupling to MALDI MS for neuropeptide analysis. PMID:21696746

  4. Determination of in vitro- and in vivo-formed DNA adducts of 2-amino-3-methylimidazo[4,5-f]quinoline by capillary liquid chromatography/microelectrospray mass spectrometry.

    PubMed

    Gangl, E T; Turesky, R J; Vouros, P

    1999-10-01

    Capillary liquid chromatography/microelectrospray mass spectrometry has been applied to the detection of deoxyribonucleoside adducts of the food-derived mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) from in vitro and in vivo sources. Constant neutral loss (CNL) and selective reaction monitoring (SRM) techniques with a triple-quadrupole mass spectrometer enabled sensitive and specific detection of IQ adducts in vitro and in animals. Detection of 1 adduct in 10(4) unmodified bases is achieved using CNL scanning detection, while the lower detection limits using SRM approach 1 adduct in 10(7) unmodified bases using 300 microg of DNA. The DNA adducts N-(deoxyguanosin-8-yl)-2-amino-3-methylimidazo[4, 5-f]quinoline (dG-C8-IQ) and 5-(deoxyguanosin-N(2)-yl)-2-amino-3-methylimidazo[4,5-f]quinoline (dG-N(2)-IQ) were detected in kidney tissues of chronically treated cynomolgus monkeys at levels and in proportions consistent with previously published (32)P-postlabeling data [Turesky, R. J., et al. (1996) Chem. Res. Toxicol. 9, 403-408]. Thus, capillary tandem LC/MS is a highly sensitive technique, which can be used to screen for DNA adducts in vivo.

  5. Determination of chloramphenicol, thiamphenicol and florfenicol in milk and honey using modified QuEChERS extraction coupled with polymeric monolith-based capillary liquid chromatography tandem mass spectrometry.

    PubMed

    Liu, Hsiang-Yu; Lin, Shu-Ling; Fuh, Ming-Ren

    2016-04-01

    A poly(lauryl methacrylate-co-methacrylic acid-co-ethylene glycol dimethacrylate) [LMA-MAA-EDMA] monolithic column was used to simultaneously determine amphenicol antibiotics (chloramphenicol/CAP, thiamphenicol/TAP, and florfenicol/FF) in milk and honey samples by capillary liquid chromatography tandem mass spectrometry (LC-MS/MS). QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was optimized for sample pretreatment. Good linearity (0.1-15 ng g(-1)) and extraction recoveries (95.8-100.2% and 95.6-99.3% for milk and honey samples, respectively; n=3) with minor matrix effect (≦ 5% ion suppression) were obtained. Limits of detection were estimated at 0.02-0.045 ng g(-1). Good intra-day/inter-day precision (0.2-9.1%/0.3-8.7%) and accuracy (90.5-110.0%/93.4-109.3%) were achieved. With more than 200 analyses of real samples, no noticeable carry-over and deterioration of separation efficiency were observed using the monolithic column. The applicability of the developed QuEChERS-capillary LC-MS/MS method was demonstrated by determining the occurrence of CAP, TAP, and FF in various milk and honey samples.

  6. Separation and characterization of humic acids from Antarctica by capillary electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Inclusion complexes of humic acids with cyclodextrins.

    PubMed

    Gajdosová, Dagmar; Novotná, Klára; Prosek, Pavel; Havel, Josef

    2003-10-03

    A new capillary electrophoresis procedure based on micellar electrokinetic capillary chromatography for the separation of humic acids (HAs) isolated from Antarctica soil was developed. The HAs were separated and characterized using a background electrolyte containing 0.09 M borate+0.09 M Tris+0.001 M EDTA (BTE) of pH 8.3, modified with alpha-, beta-, or gamma-cyclodextrins (CDs) and sodium dodecyl sulfate. It was found that from alkaline solution of HAs in the presence of CDs, the HAs are not completely precipitated with a strong acid and a certain part (some fractions) remains soluble. Mass spectrometry shows that HAs contain 15-25 simple low-Mr compounds and several families of compounds with similar structure (m/z approximately 800-1200). Comparison of HA analysis from Antarctica soil with those of soil HAs from the American continent show a high similarity between the samples and confirm several identical compounds and some with very similar structural units.

  7. Separation of intact proteins on γ-ray-induced polymethacrylate monolithic columns: A highly permeable stationary phase with high peak capacity for capillary high-performance liquid chromatography with high-resolution mass spectrometry.

    PubMed

    Simone, Patrizia; Pierri, Giuseppe; Foglia, Patrizia; Gasparrini, Francesca; Mazzoccanti, Giulia; Capriotti, Anna Laura; Ursini, Ornella; Ciogli, Alessia; Laganà, Aldo

    2016-01-01

    Polymethacrylate-based monolithic capillary columns, prepared by γ-radiation-induced polymerization, were used to optimize the experimental conditions (nature of the organic modifiers, the content of trifluoroacetic acid and the column temperature) in the separation of nine standard proteins with different hydrophobicities and a wide range of molecular weights. Because of the excellent permeability of the monolithic columns, an ion-pair reversed-phase capillary liquid chromatography with high-resolution mass spectrometry method has been developed by coupling the column directly to the mass spectrometer without a flow-split and using a standard electrospray interface. Additionally, the high working flow and concomitant high efficiency of these columns allowed us to employ a longer column (up to 50 cm) and achieve a peak capacity value superior to 1000. This work is motivated by the need to develop new materials for high-resolution chromatographic separation that combine chemical stability at elevated temperatures (up to 75°C) and a broad pH range, with a high peak capacity value. The advantage of the γ-ray-induced monolithic column lies in the batch-to-batch reproducibility and long-term high-temperature stability. Their proven high loading capacity, recovery, good selectivity and high permeability, moreover, compared well with that of a commercially available poly(styrene-divinylbenzene) monolithic column, which confirms that such monolithic supports might facilitate analysis in proteomics.

  8. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    SciTech Connect

    Ombaba, J.M.

    1992-01-01

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (mytilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienylmanganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were considered. The evaluation of a computer-aided optimization program, Drylab GC, using spearmint oil and Environmental Protection Agency (EPA) standard mixture as probes is discussed. The program is used for separation optimization and prediction of gas chromatographic parameters. The program produces a relative resolution map (RRM) which guides the analyst in selecting the most favorable temperature programming rate for the separation.

  9. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

    USGS Publications Warehouse

    Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

    1995-01-01

    A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

  10. Capillary electrophoresis.

    PubMed

    Compton, S W; Brownlee, R G

    1988-05-01

    While capillary electrophoresis, or historically related techniques, have been used for over a century, and recognition of the value of this separation methodology has certainly grown rapidly in the past few years, the technique has generally been used by analytical chemists, particularly in Europe and Japan, and small groups of researchers in the United States. Many of the basic instrumentation problems have been solved only relatively recently, and researchers using capillary electrophoresis are now turning their attention to studying specific applications which demonstrate the potential versatility of this electrophoretic technique. The appearance of standardized commercial instrumentation is imminent. With the availability of such technology, capillary electrophoresis will no longer be an academic curiosity, but rather a tool with the potential for routine separations of diverse samples of interest to analyst, researcher, and clinician.

  11. A novel capillary microextraction on ordered mesoporous titania coating combined with electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of V, Cr and Cu in environmental and biological samples.

    PubMed

    Wu, Yiwei; Hu, Bin; Hu, Wenling; Jiang, Zucheng; Li, Boyangzi

    2007-04-01

    In this work, an ordered mesoporous titania film was introduced to coat a capillary by means of sol-gel technique. Sol-gel titania coating was developed for the preconcentration/separation of trace V, Cr and Cu by capillary microextraction (CME), and the adsorbed analytes were eluted for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) detection. By immobilizing sol-gel titania on the inner surface of a fused-silica microextraction capillary, the sol-gel titania coating was prepared easily. Its adsorption properties, stability and the factors affecting the adsorption behaviors of V, Cr and Cu were investigated in detail. At pH range of 7 to 9, the titania-coated capillary (50 cm x 0.25 mm) is selective towards V, Cr and Cu, and the target analytes could be desorbed quantitatively with 50 microl of 1.0 mol l(-1) HNO3 at the rate of 0.05 ml min(-1). With a consumption of 2 ml sample solution, an enrichment factor of 33.3, and a detection limit (3 s) of 1.1 pg ml(-1) (10.5 fg) for V; 3.3 pg ml(-1) (33.0 fg) for Cr and 6.3 pg ml(-1) (63.1 fg) for Cu respectively were obtained. The precisions Relative Standard Deviations (RSDs) for nine replicate measurements of 1 ng ml(-1) V, Cr and Cu were 3.4, 5.1 and 6.4%, respectively. The proposed method has been applied to the determination of V, Cr and Cu in human urine and lake water, and the recoveries for these elements were 89.2 approximately 105%. The developed method was also applied to the determination of the target elements in NIES No. 10-a (rice flour-unpolished) and NIES No. 9 (sargasso) certified reference materials, and the results found are in good agreement with the certified values. Copyright 2007 John Wiley & Sons, Ltd.

  12. Analysis of Listeria using exogenous volatile organic compound metabolites and their detection by static headspace-multi-capillary column-gas chromatography-ion mobility spectrometry (SHS-MCC-GC-IMS).

    PubMed

    Taylor, Carl; Lough, Fraser; Stanforth, Stephen P; Schwalbe, Edward C; Fowlis, Ian A; Dean, John R

    2017-07-01

    Listeria monocytogenes is a Gram-positive bacterium and an opportunistic food-borne pathogen which poses significant risk to the immune-compromised and pregnant due to the increased likelihood of acquiring infection and potential transmission of infection to the unborn child. Conventional methods of analysis suffer from either long turn-around times or lack the ability to discriminate between Listeria spp. reliably. This paper investigates an alternative method of detecting Listeria spp. using two novel enzyme substrates that liberate exogenous volatile organic compounds in the presence of α-mannosidase and D-alanyl aminopeptidase. The discriminating capabilities of this approach for identifying L. monocytogenes from other species of Listeria are investigated. The liberated volatile organic compounds (VOCs) are detected using an automated analytical technique based on static headspace-multi-capillary column-gas chromatography-ion mobility spectrometry (SHS-MCC-GC-IMS). The results obtained by SHS-MCC-GC-IMS are compared with those obtained by the more conventional analytical technique of headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results found that it was possible to differentiate between L. monocytogenes and L. ivanovii, based on their VOC response from α-mannosidase activity.

  13. Separation of plutonium and neptunium species by capillary electrophoresis-inductively coupled plasma-mass spectrometry and application to natural groundwater samples.

    PubMed

    Kuczewski, Bernhard; Marquardt, Christian M; Seibert, Alice; Geckeis, Horst; Kratz, Jens Volker; Trautmann, Norbert

    2003-12-15

    Capillary electrophoresis (CE) was coupled to ICPMS in order to combine the good performance of this separation technique with the high sensitivity of the ICPMS for the analysis of plutonium and neptunium oxidation states. The combination of a fused-silica capillary with a MicroMist AR 30-I-FM02 nebulizer and a Cinnabar small-volume cyclonic spray chamber yielded the best separation results. With this setup, it was possible to separate a model element mixture containing neptunium (NpO2(+)), uranium (UO2(2+)), lanthanum (La3+), and thorium (Th4+) in 1 M acetic acid. The same conditions were also suitable for the separation of various oxidation states of plutonium and neptunium in different aqueous samples. All separations were obtained within less than 15 min. A detection limit of 50 ppb identical with 2 x 10(-7) M (3-fold standard deviation of a blank) was achieved. To prove the negligible disturbance of the plutonium and neptunium redox equilibria during the CE separations, plutonium and neptunium speciation by CE-ICPMS in acidic solutions was compared with the results of UV/visible absorption spectroscopy and was found to be in good agreement. The CE-ICPMS system was also applied to study the reduction of Pu(VI) in a humic acid-containing groundwater at different pH values.

  14. Implementation of a design of experiments to study the influence of the background electrolyte on separation and detection in non-aqueous capillary electrophoresis-mass spectrometry.

    PubMed

    Posch, Tjorben Nils; Müller, Alexander; Schulz, Wolfgang; Pütz, Michael; Huhn, Carolin

    2012-02-01

    Non-aqueous capillary electrophoresis (NACE) background electrolytes are most often composed of a mixture of methanol and acetonitrile (ACN) with soluble ammonium salts added as electrolyte. In this study on NACE-MS, we used a mixture of glacial acetic acid and ACN giving rise to an acidic background electrolyte (BGE) with a very low dielectric constant. Impressive changes in selectivity and resolution were observed for structurally closely related indole alkaloids including diastereomers upon addition of ammonium formate as electrolyte and upon variation of the solvent ratio. In order to obtain best separation and MS detection conditions and to reveal the influence of the parameters of the BGE on separation and detection and vice versa of the MS parameters on separation, an optimization strategy was employed using a design of experiments in a central composite design with response surface methodology. It was proven that at high electroosmotic flow conditions capillary electrophoretic separations and thus optimization can be realized without interference from the coupling to an MS system. Several significantly interacting parameters were revealed, which are not accessible with classical univariate optimization approaches. With this optimization, alkaloid mixtures from a plant extract of Mitragyna speciosa, containing a large number of diastereomeric compounds were successfully separated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Development and Characterization of a Novel Plug and Play Liquid Chromatography-Mass Spectrometry (LC-MS) Source That Automates Connections between the Capillary Trap, Column, and Emitter*

    PubMed Central

    Bereman, Michael S.; Hsieh, Edward J.; Corso, Thomas N.; Van Pelt, Colleen K.; MacCoss, Michael J.

    2013-01-01

    We report the development and characterization of a novel, vendor-neutral ultra-high pressure-compatible (∼10,000 p.s.i.) LC-MS source. This device is the first to make automated connections with user-packed capillary traps, columns, and capillary emitters. The source uses plastic rectangular inserts (referred to here as cartridges) where individual components (i.e. trap, column, or emitter) can be exchanged independent of one another in a plug and play manner. Automated robotic connections are made between the three cartridges using linear translation powered by stepper motors to axially compress each cartridge by applying a well controlled constant compression force to each commercial LC fitting. The user has the versatility to tailor the separation (e.g. the length of the column, type of stationary phase, and mode of separation) to the experimental design of interest in a cost-effective manner. The source is described in detail, and several experiments are performed to evaluate the robustness of both the system and the exchange of the individual trap and emitter cartridges. The standard deviation in the retention time of four targeted peptides from a standard digest interlaced with a soluble Caenorhabditis elegans lysate ranged between 3.1 and 5.3 s over 3 days of analyses. Exchange of the emitter cartridge was found to have an insignificant effect on the abundance of various peptides. In addition, the trap cartridge can be replaced with minimal effects on retention time (<20 s). PMID:23422586

  16. Capillary Electrophoresis-nanoelectrospray Ionization-selected Reaction Monitoring Mass Spectrometry Via A True Sheathless Metal-coated Emitter Interface For Robust And High Sensitivity Sample Quantification

    SciTech Connect

    Guo, Xuejiang; Fillmore, Thomas L.; Gao, Yuqian; Tang, Keqi

    2016-03-30

    A new sheathless CITP/CZE-MS interface, based on a commercially available capillary with an integrated metal coated ESI emitter, was developed in this study aiming at overcoming the reproducibility and ruggedness problems, suffered to a certain degree by almost all the available CE-MS interfaces, and pushing the CE-MS technology suitable for routine sample analysis with high sensitivity. The new CITP/CZE-MS interface allows the electric contact between ESI voltage power supply and the CE separation liquid by using a conductive liquid that comes in contact with the metal coated surface of the ESI emitter, making it a true sheathless CE-MS interface. Stable electrospray was established by avoiding the formation of gas bubbles from electro chemical reaction at the emitter tip or inside of the CE capillary. Crucial operating parameters, such as sample loading volume, flow rate, and separation voltage, were systematically evaluated for their effects on both CITP/CZE separation efficiency and MS detection sensitivity. Around one hundred CITP/CZE-MS analyses can be easily achieved by using the new sheathless CITP/CZE interface without a noticeable loss of metal coating on the ESI emitter surface, or degrading of the ESI emitter performance. The reproducibility in analyte migration time and quantitative performance of the new interface was experimentally evaluated to demonstrate a LOQ bellow 5 attomole.

  17. Determination of bromophenols as dioxin precursors in combustion gases of fire retarded extruded polystyrene by sorptive sampling-capillary gas chromatography-mass spectrometry.

    PubMed

    Desmet, Koen; Schelfaut, Marc; Sandra, Pat

    2005-04-15

    Extruded polystyrene (XPS) is often treated with hexabromocyclododecane (HBCD) as fire retardant (FR). Because of its aliphatic structure, HBCD is not suspected to cause formation of polybrominated dioxins upon combustion. Precursors of polybrominated dioxins, namely bromophenols, were detected during tubular furnace combustion experiments of FR-XPS in combination with sorptive enrichment on polydimethylsiloxane followed by on-line thermal desorption-capillary GC/MS. The highest concentration of mono- and tribromophenols detected were 85.9 and 3.7 mg kg(-1), respectively, at a temperature of 700 degrees C, while a temperature of 500 degrees C yielded the highest concentration of dibromophenols namely 10.4 mg kg(-1). At a combustion temperature of 900 degrees C no bromophenols were detected.

  18. Facile analysis of metabolites by capillary electrophoresis coupled to matrix-assisted laser desorption/ionization mass spectrometry using target plates with polysilazane nanocoating and grooves.

    PubMed

    Amantonico, Andrea; Urban, Pawel L; Zenobi, Renato

    2009-08-01

    We present an inexpensive method and apparatus for the deposition of analytes separated by capillary electrophoresis (CE) onto a custom-designed matrix-assisted laser desorption/ionization (MALDI) target plate. This dedicated CE-MALDI plate is coated with an omniphobic polysilazane nanocoating and has an array of parallel grooves acting as recipients of the separation effluent. The 3-D pattern in the top layer of the coated plate greatly improves loading of the matrix solution prior to separation and facilitates deposition of the separated species. We demonstrate application of this straightforward protocol to the analysis of metabolites from the central metabolic pathway in a complex biological sample spiked with small molecule standards.

  19. Evaluation of fritless solid-phase extraction coupled on-line with capillary electrophoresis-mass spectrometry for the analysis of opioid peptides in cerebrospinal fluid.

    PubMed

    Medina-Casanellas, Silvia; Tak, Yvonne H; Benavente, Fernando; Sanz-Nebot, Victoria; Sastre Toraño, Javier; Somsen, Govert W; de Jong, Gerhardus J

    2014-10-01

    Fritless SPE on-line coupled to CE with UV and MS detection (SPE-CE-UV and SPE-CE-MS) was evaluated for the analysis of opioid peptides. A microcartridge of 150 μm id was packed with a C18 sorbent (particle size > 50 μm), which was retained between a short inlet capillary and a separation capillary (50 μm id). Several experimental parameters were optimized by SPE-CE-UV using solutions of dynorphin A (DynA), endomorphin 1 (End1), and methionine-enkephaline (Met). A microcartridge length of 4 mm was selected, sample was loaded for 10 min at 930 mbar and the retained peptides were eluted with 67 nL of an acidic hydro-organic solution. Using SPE-CE-MS, peak area and migration time repeatabilities for the three opioid peptides were 12-27% and 4-5%, respectively. SPE recovery was lower for the less hydrophobic DynA (22%) than for End1 (66%) and Met (78%) and linearity was satisfactory in all cases between 5 and 60 ng/mL. The LODs varied between 0.5 and 1.0 ng/mL which represent an enhancement of two orders of magnitude when compared with CE-MS. Cerebrospinal fluid (CSF) samples spiked with the opioid peptides were analyzed to demonstrate the applicability to biological samples. Peak area and migration time repeatabilities were similar to the standard solutions and the opioid peptides could be detected down to 1.0 ng/mL.

  20. High-efficiency headspace sampling of volatile organic compounds in explosives using capillary microextraction of volatiles (CMV) coupled to gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Fan, Wen; Almirall, José

    2014-03-01

    A novel geometry configuration based on sorbent-coated glass microfibers packed within a glass capillary is used to sample volatile organic compounds, dynamically, in the headspace of an open system or in a partially open system to achieve quantitative extraction of the available volatiles of explosives with negligible breakthrough. Air is sampled through the newly developed sorbent-packed 2 cm long, 2 mm diameter capillary microextraction of volatiles (CMV) and subsequently introduced into a commercially available thermal desorption probe fitted directly into a GC injection port. A sorbent coating surface area of ∼5 × 10(-2) m(2) or 5,000 times greater than that of a single solid-phase microextraction (SPME) fiber allows for fast (30 s), flow-through sampling of relatively large volumes using sampling flow rates of ∼1.5 L/min. A direct comparison of the new CMV extraction to a static (equilibrium) SPME extraction of the same headspace sample yields a 30 times improvement in sensitivity for the CMV when sampling nitroglycerine (NG), 2,4-dinitrotoluene (2,4-DNT), and diphenylamine (DPA) in a mixture containing a total mass of 500 ng of each analyte, when spiked into a liter-volume container. Calibration curves were established for all compounds studied, and the recovery was determined to be ∼1 % or better after only 1 min of sampling time. Quantitative analysis is also possible using this extraction technique when the sampling temperature, flow rate, and time are kept constant between calibration curves and the sample.

  1. Capillary liquid chromatography with diode array and mass spectrometry detection for heterocyclic aromatic amine determination in ready-to-eat food treated with electron-beam irradiation.

    PubMed

    Gonzalo-Lumbreras, R; Rosales-Conrado, N; León-González, M E; Pérez-Arribas, L V; Polo-Díez, L M

    2010-10-22

    In the present paper, we have developed a capillary liquid chromatography with MS detection for the determination at ngg⁻¹ levels of four heterocyclic aromatic amines (MeIQx, norharman, harman and harmine), a group of mutagenic and carcinogenic compounds that can potentially be produced in protein-rich food during processing operations. They have been determined in commercial ready-to-eat (RTE) smoked salmon and soft cheese treated with E-beam irradiation. On the basis of experimental design studies and operating conditions of MS detector, best chromatographic conditions were obtained using a Luna® C¹⁸ capillary column (150 mm × 0.3 mm I.D.) with a mixture of acetonitrile-ammonium formate 5 mM pH 3.6 buffer (13:87, v/v) as mobile phase. To improve sensitivity, large injection volumes (20 μL) and injection solutions of low elution strength were employed. Sample preparation procedure included a previous treatment with 1M NaOH, followed by two solid-phase extraction steps; firstly on diatomaceous earth and then on mixed-mode cartridges. Heterocyclic amines were detected neither in irradiated and in non-irradiated samples, indicating that they were not formed by the radiation effect even at doses higher than those indicated in the Food Safety Objective established by regulatory agencies. RTE food samples were spiked at concentration levels in the range 10-30 ngg⁻¹. Recoveries higher than 85% (n=3 for each spiked level) were obtained, showing the effectiveness of the proposed methodology.

  2. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  3. Sol-gel zirconia coating capillary microextraction on-line hyphenated with inductively coupled plasma mass spectrometry for the determination of Cr, Cu, Cd and Pb in biological samples.

    PubMed

    Wu, Yiwei; Hu, Bin; Jiang, Zucheng; Feng, Yuqi; Lu, Peng; Li, Boyangzi

    2006-01-01

    A sol-gel zirconia coating was developed for the preconcentration/separation of trace Cr, Cu, Cd and Pb by capillary microextraction, and the adsorbed analytes were on-line eluted for detection using inductively coupled plasma mass spectrometry (ICP-MS). By immobilizing sol-gel zirconia on the inner surface of a fused-silica capillary, the sol-gel zirconia coating was simply prepared. Its adsorption properties, stability and the factors affecting the adsorption behaviors of Cr, Cu, Cd and Pb were investigated in detail. In the pH range from 7.8 to 10, the zirconia-coated capillary (35 cm x 0.15 mm) is selective towards Cr, Cu, Cd and Pb, and the analyzed ions could be desorbed quantitatively with 0.2 mL of 0.5 mol/L HNO(3) at a rate of 0.2 mL/min. With a consumption of 1.25 mL sample solution, an enrichment factor of 6.25, and detection limits (3sigma) of 9.9 pg/mL Cr, 17.9 pg/mL Cu, 4.5 pg/mL Cd and 3.7 pg/mL Pb were obtained. The precisions for nine replicate measurements of 1 ng/mL Cr, Cu, Cd and Pb were 4.9% Cr, 2.2% Cu, 2.0% Cd and 3.2% Pb (RSD), respectively. The proposed procedure has been applied to the determination of Cr, Cu, Cd and Pb in human urine, which was subjected to microwave-assisted digestion prior to analysis, and the recoveries for these elements were 89.2-101.8%. In order to validate the developed procedure, a NIES No.10-a Rice Flour-Unpolished certified reference material and a BCR No. 184 Bovine Muscle certified reference material were analyzed, and the results are in good agreement with the certified values. Copyright (c) 2006 John Wiley & Sons, Ltd.

  4. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Ombaba, Jackson M.

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The device exhibits a stable signal because the plasma is self-seeding and reignites itself every half cycle. A tesla coil is not required to commence generation of the plasma if the ac voltage applied is greater than the breakdown voltage of the plasma-supporting gas. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (Mvutilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienyl manganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer (common room humidifier) was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were also considered. Figures of merits of selected elements both in absorption and emission modes are reported. The evaluation of a computer-aided optimization program, Drylab GC, using

  5. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Capillary Isoelectric Focusing-Tandem Mass Spectrometry And Reversed-Phase Liquid Chromatography-Tandem Mass Spectrometry For Quantitative Proteomic Analysis Of Differentiating PC12 Cells By Eight-Plex iTRAQ

    PubMed Central

    Zhu, Guijie; Sun, Liangliang; Keithley, Richard B.; Dovichi, Norman J.

    2013-01-01

    We report the application of capillary isoelectric focusing for quantitative analysis of a complex proteome. Biological duplicates were generated from PC12 cells at days 0, 3, 7, and 12 following treatment with nerve growth factor. These biological duplicates were digested with trypsin, labeled using eight-plex iTRAQ chemistry, and pooled. The pooled peptides were separated into 25 fractions using reversed-phase liquid chromatography (RPLC). Technical duplicates of each fraction were separated by capillary isoelectric focusing (cIEF) using a set of amino acids as ampholytes. The cIEF column was interfaced to an Orbitrap Velos mass spectrometer with an electrokinetically-pumped sheath-flow nanospray interface. This HPLC-cIEF-ESIMS/MS approach identified 835 protein groups and produced 2,329 unique peptides IDs. The biological duplicates were analyzed in parallel using conventional strong-cation exchange (SCX) – RPLC-ESIMS/MS. The iTRAQ peptides were first separated into eight fractions using SCX. Each fraction was then analyzed by RPLC-ESI-MS/MS. The SCX-RPLC approach generated 1,369 protein groups and 3,494 unique peptide IDs. For protein quantitation, 96 and 198 differentially expressed proteins were obtained with RPLC-cIEF and SCX-RPLC, respectively. The combined set identified 231 proteins. Protein expression changes measured by RPLC-cEIF and SCX-RPLC were highly correlated. PMID:23822771

  7. Understanding mechanisms of pressure-assisted electrokinetic injection: application to analysis of bromate, arsenic and selenium species in drinking water by capillary electrophoresis-mass spectrometry.

    PubMed

    Zhang, Huijuan; Gavina, Jennilee; Feng, Yong-Lai

    2011-05-20

    The mechanism underlying the enrichment power by pressure-assisted electrokinetic injection (PAEKI) in capillary electrophoresis (CE) was investigated for on-line pre-concentration of arsenic [As(III) and As(V)], selenium [Se(IV) and Se(VI)] and bromate (BrO(3)(-)). Analyte diffusion behaviour from PAEKI sample plugs were evaluated by monitoring peak broadening as a function of stagnant time and position in the capillary. During PAEKI, anionic analytes accumulate at the sample-separation buffer boundary. We proposed that a counter-ion layer formed in PAEKI, where a cation layer was formed at the separation buffer side of boundary. The cation layer served as a soft boundary which impeded zone broadening via electrostatic attraction between layers. This effect likely played an important role in maintaining focused analyte bands by suppressing diffusion. Comparison of analyte behaviour in PAEKI injected sample plugs to behaviour in hydrodynamically injected ones proved the existence of a counter-ion layer. The dependence of analyte diffusion in PAEKI plugs on electrochemical properties (viscosity, conductivity, electrophoretic mobility) further supported the hypothesis. Additionally, it was noted that analytes with low electrophoretic mobility were more efficiently pre-concentrated by PAEKI and were less subject to forces of dispersion than analytes with greater electrophoretic mobility. PAEKI-CE coupled to electrospray tandem mass spectroscopy (ESI-MS/MS) was then optimized and validated for detection of arsenic, selenium and bromate in water samples. On-line enrichment of the target analytes was achieved with 1-3 ng mL(-1) detection limits, which was below the maximum contaminant levels in drinking water for all five anions studied. Noteworthy, the potential of the method for unbiased detection of molecular species in untreated water was demonstrated. No contamination was detected in the water samples tested; however, recovery was 90-118% for spiked samples. The

  8. Coupling sodium dodecyl sulfate-capillary polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry via a poly(tetrafluoroethylene) membrane.

    PubMed

    Lu, Joann J; Zhu, Zaifang; Wang, Wei; Liu, Shaorong

    2011-03-01

    Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique for proteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gel electrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automated operation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolved proteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but is extremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MS detection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE) membranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDS bound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we can immunoblot and Coomassie-stain the proteins collected on these membranes.

  9. Identification of Novel Site-Specific Alterations in the Modification Level of Myelin Basic Protein Isolated from Mouse Brain at Different Ages Using Capillary Electrophoresis-Mass Spectrometry.

    PubMed

    Sarg, Bettina; Faserl, Klaus; Lindner, Herbert H

    2017-10-01

    Myelin basic protein (MBP) is a multifunctional protein involved in maintaining the stability and integrity of the myelin sheath by a variety of interactions with membranes and other proteins. MBP is subjected to extensive posttranslational modifications (PTMs) that are known to be crucial for the regulation of these interactions. Here, we report capillary electrophoresis-mass spectrometric (CE-MS) analysis for the separation and identification of MBP peptides that incorporate the same PTM at different sites, creating multiple localization variants, and the ability to analyze challenging modifications such as asparagine and glutamine deamidation, isomerization, and arginine citrullination. Moreover, we observed site-specific alterations in the modification level of MBP purified from brain of mice of different age. In total, we identified 40 modifications at 33 different sites, which include both previously reported and seven novel modifications. The identified modifications include Nα-terminal acetylation, mono- and dimethylation, phosphorylation, oxidation, deamidation, and citrullination. Notably, some new sites of arginine methylation overlap with the sites of citrullination. Our results highlight the need for sensitive and efficient techniques for a comprehensive analysis of PTMs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Screening of mammalian target of rapamycin inhibitors in natural product extracts by capillary electrophoresis in combination with high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Yanmei; Li, Feng; Li, Mingxia; Kang, Jingwu

    2015-04-03

    In this study, capillary electrophoresis (CE) combined with HPLC-MS/MS were used as a powerful platform for screening of inhibitors of mammalian target of rapamycin (mTOR) in natural product extracts. The screening system has been established by using 5-carboxyfluorescein labeled substrate peptide F-4EBP1, a known mTOR inhibitor AZD8055, and a small chemical library consisted of 18 natural product extracts. Biochemical screening of natural product extracts was performed by CE with laser induced fluorescence detection. The CE separation allowed a quantitative measurement of the phosphorylated product, hence the quantitation of enzymatic inhibition as well as inhibition kinetics. The hits are readily identified as long as the peak area of the phosphorylated product is reduced in comparison with the negative control. Subsequent assay-guided isolation of the active natural product extract was performed with HPLC-MS/MS to track the particular active components. The structures of the identified active components were elucidated by the molecular ions and fragmentation information provided by MS/MS analysis. The CE-based assay method only requires minute pure compounds, which can be readily purified by HPLC. Therefore, the combination of CE and HPLC-MS/MS provides a high-throughput platform for screening bioactive compounds from the crude nature extracts. By taking the advantage of the screening system, salvianolic acid A and C in extract of Salvia miltiorrhiza were discovered as the new mTOR inhibitors.

  11. Application of capillary isotachophoresis-based multidimensional separations coupled with electrospray ionization-tandem mass spectrometry for characterization of mouse brain mitochondrial proteome

    PubMed Central

    Fang, Xueping; Wang, Weijie; Yang, Li; Chandrasekaran, Krish; Kristian, Tibor; Balgley, Brian M.; Lee, Cheng S.

    2017-01-01

    By employing a capillary ITP (CITP)/CZE-based proteomic technology, a total of 1795 distinct mouse Swiss-Prot protein entries (or 1705 nonredundant proteins) are identified from synaptic mitochondria isolated from mouse brain. The ultrahigh resolving power of CITP/CZE is evidenced by the large number of distinct peptide identifications measured from each CITP fraction together with the low peptide fraction overlapping among identified peptides. The degree of peptide overlapping among CITP fractions is even lower than that achieved using combined CIEF/nano-RP LC separations for the analysis of the same mitochondrial sample. When evaluating the protein sequence coverage by the number of distinct peptides mapping to each mitochondrial protein identification, CITP/CZE similarly achieves superior performance with 1041 proteins (58%) having 3 or more distinct peptides, 233 (13%) having 2 distinct peptides, and 521 (29%) having a single distinct peptide. The reproducibility of protein identifications is found to be around 86% by comparing proteins identified from repeated runs of the same mitochondrial sample. The analysis of the mouse mitochondrial proteome by two CITP/CZE runs results in the detection of 2095 distinct mouse Swiss-Prot protein entries (or 1992 nonredundant proteins), corresponding to 59% coverage of the updated Maestro mitochondrial reference set. The collective analysis from combined CITP/CZE and CIEF-based proteomic studies yields the identification of 2191 distinct mitochondrial protein entries (or 2082 nonredundant proteins), corresponding to 76% coverage of the MitoP2-database reference set. PMID:18425750

  12. Profiling of cis-diol-containing nucleosides and ribosylated metabolites by boronate-affinity organic-silica hybrid monolithic capillary liquid chromatography/mass spectrometry.

    PubMed

    Jiang, Han-Peng; Qi, Chu-Bo; Chu, Jie-Mei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-01-14

    RNA contains a large number of modified nucleosides. In the metabolic re-exchange of RNA, modified nucleosides cannot be recycled and are thus excreted from cells into biological fluids. Determination of endogenous modified nucleosides in biological fluids may serve as non-invasive cancers diagnostic methods. Here we prepared boronate-affinity organic-silica hybrid capillary monolithic column (BOHCMC) that exhibited excellent selectivity toward the cis-diol-containing compounds. We then used the prepared BOHCMC as the on-line solid-phase microextraction (SPME) column and developed an on-line SPME-LC-MS/MS method to comprehensively profile cis-diol-containing nucleosides and ribosylated metabolites in human urine. Forty-five cis-diol-containing nucleosides and ribosylated metabolites were successfully identified in human urine. And five ribose conjugates, for the first time, were identified existence in human urine in the current study. Furthermore, the relative quantification suggested 4 cis-diol-containing compounds (5'-deoxy-5'-methylthioadensine, N(4)-acetylcytidine, 1-ribosyl-N-propionylhistamine and N(2),N(2),7-trimethylguanosine) increased more than 1.5 folds in all the 3 types of examined cancers (lung cancer, colorectal cancer, and nasopharyngeal cancer) compared to healthy controls. The on-line SPME-LC-MS/MS method demonstrates a promising method for the comprehensive profiling of cis-diol-containing ribose conjugates in human urines, which provides an efficient strategy for the identification and discovery of biomarkers and may be used for the screening of cancers.

  13. Imaging MALDI mass spectrometry using an oscillating capillary nebulizer matrix coating system and its application to analysis of lipids in brain from a mouse model of Tay-Sachs/Sandhoff disease.

    PubMed

    Chen, Yanfeng; Allegood, Jeremy; Liu, Ying; Wang, Elaine; Cachón-Gonzalez, Begoña; Cox, Timothy M; Merrill, Alfred H; Sullards, M Cameron

    2008-04-15

    The quality of tissue imaging by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) depends on the effectiveness of the matrix deposition, especially for lipids that may dissolve in the solvent used for the matrix application. This article describes the use of an oscillating capillary nebulizer (OCN) to spray small droplets of matrix aerosol onto the sample surface for improved matrix homogeneity, reduced crystal size, and controlled solvent effects. This system was then applied to the analysis of histological slices of brains from mice with homozygous disruption of the hexb gene (hexb-/-), a model of Tay-Sachs and Sandhoff disease, versus the functionally normal heterozygote (hexb+/-) by imaging MALDI-MS. This allowed profiling and localization of many different lipid species, and of particular interest, ganglioside GM2, asialo-GM2 (GA2), and sulfatides (ST). The presence of these compounds was confirmed by analysis of brain extracts using electrospray ionization in conjunction with tandem mass spectrometry (MS/MS). The major fatty acid of the ceramide backbone of both GM2 and GA2 was identified as stearic acid (18:0) versus nervonic acid (24:1) for ST by both tissue-imaging MS and ESI-MS/MS. GM2 and GA2 were highly elevated in hexb-/- and were both localized in the granular cell region of the cerebellum. ST, however, was localized mainly in myelinated fiber (white matter) region of the cerebellum as well as in the brain stem with a relatively uniform distribution and had similar relative signal intensity for both hexb+/- and hexb-/- brain. It was also observed that there were distinct localizations for numerous other lipid subclasses; hence, imaging MALDI-MS could be used for "lipidomic" studies. These results illustrate the usefulness of tissue-imaging MALDI-MS with matrix deposition by OCN for histologic comparison of lipids in tissues such as brains from this mouse model of Tay-Sachs and Sandhoff disease.

  14. Identification of kinetin and kinetin riboside in coconut (Cocos nucifera L.) water using a combined approach of liquid chromatography-tandem mass spectrometry, high performance liquid chromatography and capillary electrophoresis.

    PubMed

    Ge, Liya; Yong, Jean Wan Hong; Goh, Ngoh Khang; Chia, Lian Sai; Tan, Swee Ngin; Ong, Eng Shi

    2005-12-27

    Kinetin (free base and riboside), which was assumed by many scientists to be a synthetic cytokinin plant growth hormone, has been detected for the first time in the endosperm liquid of fresh young coconut fruits ("coconut water"). To facilitate the study, we developed a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the identification and quantification of kinetin and kinetin riboside in purified coconut water extract sample. Following a solid-phase extraction of cytokinins in coconut water using C18 columns, the samples were further purified by Oasis MCX columns and analyzed by LC-MS/MS for kinetin and kinetin riboside. Detection by mass spectrometry was carried out using selected reaction monitoring (SRM) mode, by identifying the putative kinetin and kinetin riboside based on their characteristic fragments. Based on a signal-to-noise ratio of 3, the limits of detection in SRM mode were 0.02 microM and 0.005 microM for kinetin and kinetin riboside, respectively. Furthermore, optimal conditions for a baseline chromatographic separation of 18 cytokinin standards by high performance liquid chromatography (HPLC) were developed. The HPLC method had been employed for the confirmation and further fractionation of kinetin in coconut water extracts. The confirmation and fractionation of kinetin riboside was carried out using a further modified HPLC program due to the presence of other interfering material(s) in the sample matrix. Finally, fractions of putative kinetin and kinetin riboside collected from HPLC eluate of coconut water sample were further authenticated by independent capillary zone electrophoresis (CZE) experiment.

  15. INTESTINAL CAPILLARIES

    PubMed Central

    Clementi, Francesco; Palade, George E.

    1969-01-01

    Perfusion of the fenestrated capillaries of the intestinal mucosa of the rat with 0.05–0.1 M EDTA removes the diaphragms of the endothelial cells and detaches these cells from one another and from the basement membrane. The latter, even when completely denuded, retains effectively particles of 340 A (average) diameter. Perfusion with histamine (1 µg/ml) results in partial removal of fenestral diaphragms, occasional detachment of the endothelium from the basement membrane, and focal separation of endothelial intercellular junctions. PMID:4979362

  16. Implementation of Online Preconcentration and Microsecond Time Resolution to Capillary Electrophoresis Single Particle Inductively Coupled Plasma Mass Spectrometry (CE-SP-ICP-MS) and Its Application in Silver Nanoparticle Analysis.

    PubMed

    Mozhayeva, Darya; Strenge, Ingo; Engelhard, Carsten

    2017-07-05

    Capillary electrophoresis (CE) coupled to single particle inductively coupled plasma mass-spectrometry (SP-ICP-MS) was used for the first time with a prototype data acquisition (μsDAQ) system that features 5 μs time resolution (100% duty cycle) to separate and quantify mixtures of silver nanoparticles (Ag NPs). Additionally, an online preconcentration technique, reversed electrode polarity stacking mode (REPSM), was applied for Ag NPs analysis with CE-SP-ICP-MS for the first time. After optimization, best results were achieved using a injection time of 110 s and a constant pressure of 50 mbar in hydrodynamic injection mode. It was possible to detect 14.3 ± 1.5× more 20 nm sized, 21.0 ± 4.2× more 40 nm sized, and 27.7 ± 4.9× more 60 nm sized Ag NPs compared to the standard injection time of only 3 s. The effect of applied voltage on the NPs separation was studied, and a CE separation at 20 kV was found to be optimal for the present setup. The capability of CE-SP-ICP-MS for quantification of particle number concentration was investigated, and detection limits in the submicrogram-per-liter range were achieved. The possibility to separate 20, 40, and 60 nm sized Ag NPs simultaneously present in a mixture was demonstrated over a broad concentration range.

  17. Methods of analysis and quality-assurance practices of the U.S. Geological Survey organic laboratory, Sacramento, California; determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Crepeau, Kathryn L.; Domagalski, Joseph L.; Kuivila, Kathryn

    1994-01-01

    Analytical method and quality-assurance practices were developed for a study of the fate and transport of pesticides in the Sacramento-San Joaquin Delta and the Sacramento and San Joaquin River. Water samples were filtered to remove suspended parti- culate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide, and the pesticides were eluted with three 2-milliliter aliquots of hexane:diethyl ether (1:1). The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for analytes determined per 1,500-milliliter samples ranged from 0.006 to 0.047 microgram per liter. Recoveries ranged from 47 to 89 percent for 12 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.05 and 0.26 microgram per liter. The method was modified to improve the pesticide recovery by reducing the sample volume to 1,000 milliliters. Internal standards were added to improve quantitative precision and accuracy. The analysis also was expanded to include a total of 21 pesticides. The method detection limits for 1,000-milliliter samples ranged from 0.022 to 0.129 microgram per liter. Recoveries ranged from 38 to 128 percent for 21 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.10 and 0.75 microgram per liter.

  18. Preparation and evaluation of an immunoaffinity sorbent with Fab' antibody fragments for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry.

    PubMed

    Medina-Casanellas, Silvia; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

    2013-07-30

    An immunoaffinity (IA) sorbent with antibody fragments was prepared for the analysis of opioid peptides by on-line immunoaffinity solid-phase extraction capillary electrophoresis-mass spectrometry (IA-SPE-CE-MS). The antibody fragmentation was evaluated by MALDI-TOF-MS. Fab' fragments obtained from a polyclonal IgG antibody against Endomorphins 1 and 2 (End1 and End2) were covalently attached to succinimidyl silica particles to prepare the IA sorbent. An IA-SPE-CE-MS methodology was established analyzing standard solutions of End1 and End2 and acceptable repeatability, linearity ranges and LODs (0.5 and 5 ng mL(-1), respectively) were obtained. The LOD of End1 was slightly better than that previously obtained using an IA sorbent with intact antibodies (1 ng mL(-1)). In human plasma samples, End1 and End2 could be detected at 1 and 50 ng mL(-1), respectively, which meant an improvement of 100 and 2-fold with regard to the LODs using an IA sorbent with intact antibodies (100 ng mL(-1)).

  19. Determination of nanogram per liter concentrations of volatile organic compounds in water by capillary gas chromatography and selected ion monitoring mass spectrometry and its use to define groundwater flow directions in Edwards Aquifer, Texas

    USGS Publications Warehouse

    Buszka, P.M.; Rose, D.L.; Ozuna, G.B.; Groschen, G.E.

    1995-01-01

    A method has been developed to measure nanogram per liter amounts of selected volatile organic compounds (VOCs) including dichlorodifluoromethane, trichlorofluoromethane, cis-1,2-dichloroethene, trichloroethene, tetrachloroethene, and the isomers of dichlorobenzene in water. The method uses purge-and-trap techniques on a 100 mL sample, gas chromatography with a megabore capillary column, and electron impact, selected ion monitoring mass spectrometry. Minimum detection levels for these compounds ranged from 1 to 4 ng/L in water. Recoveries from organic-free distilled water and natural groundwater ranged from 70.5% for dichlorodifluoromethane to 107.8% for 1,4-dichlorobenzene. Precision was generally best for cis-1,2-dichloroethene, tetrachloroethene, and the dichlorobenzene isomers and worst for dichlorodifluoromethane and trichlorofluoromethane. Blank data indicated persistent, trace-level introduction of dichlorodifluoromethane, 1,4-dichlorobenzene, and tetrachloroemene to samples during storage and shipment at concentrations less than the method reporting limits. The largest concentrations of the selected VOCs in 27 water samples from the Edwards aquifer near San Antonio, TX, were from confined-zone wells near an abandoned landfill. The results defined a zone of water with no detectable VOCs in nearly all of the aquifer west of San Antonio and from part of the confined zone beneath San Antonio.

  20. A fully automated system with on-line micro solid-phase extraction combined with capillary liquid chromatography-tandem mass spectrometry for high throughput analysis of microcystins and nodularin-R in tap water and lake water.

    PubMed

    Shan, Yuanhong; Shi, Xianzhe; Dou, Abo; Zou, Cunjie; He, Hongbing; Yang, Qin; Zhao, Sumin; Lu, Xin; Xu, Guowang

    2011-04-01

    Microcystins and nodularins are cyclic peptide hepatotoxins and tumour promoters from cyanobacteria. The present study describes the development, validation and practical application of a fully automated analytical method based on on-line micro solid-phase extraction-capillary liquid chromatography-tandem mass spectrometry for the simultaneous determination of seven microcystins and nodularin-R in tap water and lake water. Aliquots of just 100 μL of water samples are sufficient for the detection and quantification of all eight toxins. Selected reaction monitoring was used to obtain the highest sensitivity. Good linear calibrations were obtained for microcystins (50-2000ng/L) and nodularin-R (25-1000 ng/L) in spiked tap water and lake water samples. Excellent interday and intraday repeatability were achieved for eight toxins with relative standard deviation less than 15.7% in three different concentrations. Acceptable recoveries were achieved in the three concentrations with both tap water matrix and lake water matrix and no significant matrix effect was found in tap water and lake water except for microcystin-RR. The limits of detection (signal to noise ratio=3) of toxins were lower than 56.6 ng/L which is far below the 1 μg/L defined by the World Health Organization provisional guideline for microcystin-LR. Finally, this method was successfully applied to lake water samples from Tai lake and proved to be useful for water quality monitoring.

  1. Accurate mass measurements for the confirmation of Sudan azo-dyes in hot chilli products by capillary liquid chromatography-electrospray tandem quadrupole orthogonal-acceleration time of flight mass spectrometry.

    PubMed

    Calbiani, F; Careri, M; Elviri, L; Mangia, A; Zagnoni, I

    2004-11-26

    The potential of capillary liquid chromatography (microLC)-quadrupole/time-of-flight mass spectrometry (Q-TOF MS) for the confirmation of Sudan I, II, III and IV azo-dyes as contaminants in hot-chilli food products was demonstrated. Using the microLC-electrospray ionization (ESI)-Q-TOF MS technique, accurate mass measurements of Sudan dyes were performed both on standard solutions and on matrices. Precision of exact mass measurements was calculated taking into account the ion statistics according to the number of ion sampled in the measurement. Accurate mass measurements by MS/MS experiments were performed to elucidate azo-dye fragmentation patterns. Selectivity of the microLC-Q-TOF MS method was assessed by evaluating matrix suppression effects by pre-column injection of blank hot chilli tomato sauce matrices. The results were compared with those obtained on a LC-triple quadrupole-MS system. Confirmation of Sudan I present in hot chill tomato sauce samples was obtained by accurate mass measurements. In real samples trueness of exact mass measurements was estimated to be 1.6 and 4.4 ppm when calculated for hot chilli tomato sauce and hot chilli tomato with cheese sauce samples, respectively; precision was calculated around 9.5 ppm.

  2. Elucidation of the in vitro metabolic profile of stable isotope labeled BAL19403 by accurate mass capillary liquid chromatography/quadrupole time-of-flight mass spectrometry and isotope exchange.

    PubMed

    Wind, Mathias; Gebhardt, Klaus; Grunwald, Helge; Spickermann, Jochen; Donzelli, Massimiliano; Kellenberger, Laurenz; Muller, Marc; Fullhardt, Pascal; Schmitt-Hoffmann, Anne; Schleimer, Michael

    2007-01-01

    The in vitro metabolic pattern of BAL19403, a novel macrolide antibiotic, was investigated by capillary liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS) in incubations with human microsomes. For the elucidation of the metabolic pathway, BAL19403 labeled with four deuterium atoms (D4) was used, and detection of metabolites performed using mixtures of the unlabeled (H4) BAL19403 and its D4 analogue (1:1) as substrate. All metabolites appeared with similar chromatographic behavior. MS/MS spectra of BAL19403 and its metabolites are dominated by non-informative fragment ions. Therefore, the structure of the metabolites was elucidated mainly by accurate mass measurements with subsequent proposals of elemental compositions. Main biotransformations were N-demethylation, lactone ring hydrolysis, and oxidation. Additionally, N-dealkylation of the aromatic moiety was identified. This dealkylation results not only in formation of an aldehyde, according to the classical pathway, but also in formation of the corresponding alcohol and carboxylic acid. Final elucidation of their structures was possible, since this dealkylation takes place vicinal to the deuterium-labeled part of BAL19403 and interferes with D/H exchange. The degree of D/H exchange, determined by analysis of the metabolite isotopic pattern, was used to elucidate the adjacent functional group. Copyright (c) 2007 John Wiley & Sons, Ltd.

  3. Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry for quantitative parallel reaction monitoring of peptide abundance and single-shot proteomic analysis of a human cell line

    PubMed Central

    Sun, Liangliang; Zhu, Guijie; Mou, Si; Zhao, Yimeng; Champion, Matthew M.; Dovichi, Norman J .

    2014-01-01

    We coupled capillary zone electrophoresis (CZE) with an ultrasensitive electrokinetically pumped nanospray ionization source for tandem mass spectrometry (MS/MS) analysis of complex proteomes. We first used the system for the parallel reaction monitoring (PRM) analysis of angiotensin II spiked in 0.45 mg/mL of bovine serum albumin (BSA) digest. A calibration curve was generated between the loading amount of angiotensin II and intensity of angiotensin II fragment ions. CZE-PRM generated a linear calibration curve across over 4.5 orders of magnitude dynamic range corresponding to angiotensin II loading amount from 2 amole to 150 fmole. The relative standard deviations (RSDs) of migration time were <4% and the RSDs of fragment ion intensity were ~20% or less except 150 fmole angiotensin II loading amount data (~36% RSD). We further applied the system for the first bottom up proteomic analysis of a human cell line using CZE-MS/MS. We generated 283 protein identifications from a 1 hour long, single-shot CZE MS/MS analysis of the MCF7 breast cancer cell line digest, corresponding to ~80 ng loading amount. The MCF7 digest was fractionated using a C18 solid phase extraction column; single-shot analysis of a single fraction resulted in 468 protein identifications, which is by far the largest number of protein identifications reported for a mammalian proteomic sample using CZE. PMID:25082526

  4. Evaluation of glycoalkaloids in tubers of genetically modified virus Y-resistant potato plants (var. Désirée) by non-aqueous capillary electrophoresis coupled with electrospray ionization mass spectrometry (NACE-ESI-MS).

    PubMed

    Bianco, Giuliana; Schmitt-Kopplin, Philippe; Crescenzi, Aniello; Comes, Soccorsa; Kettrup, Antonius; Cataldi, Tommaso R I

    2003-03-01

    The glycoalkaloid content of transgenic potatoes was evaluated by an optimised method based on non-aqueous capillary electrophoresis coupled on-line with electrospray ionization-mass spectrometry (NACE-ESI-MS). The potato material consisted of tubers from a conventional cv. Désirée and from three lines of modified plants resistant, intermediate and susceptible to infection by potato virus Y (PVY). The main glycoalkaloids were confirmed to be alpha-solanine and alpha-chaconine with parent ion masses m/z 852 and 868, respectively. In addition, an unknown minor peak at m/z 850.6 was found both in conventional (control) and susceptible line potato tubers. Such a compound exhibited an MS(2) spectrum with fragments ions at 704 and 396 m/z derived by loss of two ions, i.e. m/z 146 and 307, most likely corresponding to a rhamnose unit and a [glucose-(rhamnose)(2)] moiety, respectively. Up to 30-80-fold higher concentrations of total glycoalkaloids were found in the peel compared to flesh samples of all tubers examined. TGA content was nearly doubled in peel samples of resistant compared to control lines, and these levels were lower than the limit recommended for food safety, i.e. 20-60 mg of TGA per 100 g fresh weight. Moreover, it was established that tubers produced by virus-resistant clones are substantially equivalent in glycoalkaloid contents to those produced by conventional potato varieties.

  5. Comparison of proteins expressed by Pseudomonas aeruginosa strains representing initial and chronic isolates from a cystic fibrosis patient: an analysis by 2-D gel electrophoresis and capillary column liquid chromatography-tandem mass spectrometry.

    PubMed

    Hanna, S L; Sherman, N E; Kinter, M T; Goldberg, J B

    2000-10-01

    Isolates of Pseudomonas aeruginosa from chronic lung infections in cystic fibrosis (CF) patients have phenotypes distinct from those initially infecting CF patients, as well as from other clinical or environmental isolates. To gain a better understanding of the differences in these isolates, protein expression was followed using two-dimensional (2-D) gel electrophoresis and protein identification by peptide sequencing using micro-capillary column liquid chromatography-tandem mass spectrometry (microLC/MS/MS). The isolates selected for this analysis were from the sputum of a CF patient: strain 383 had a nonmucoid phenotype typical of isolates from the environment, and strain 2192, obtained from the same patient, had a mucoid phenotype typical of isolates from chronic CF lung infections. Strains 383 and 2192 were confirmed to be genetically identical by restriction endonuclease analysis, random amplified polymorphic DNA-PCR, and pulsed-field gel electrophoresis. Conditions of protein extraction were optimized for consistent high-resolution separation of several hundred proteins from these clinical isolates as detected by Coomassie staining of 2-D gels. Fourteen proteins were selected for analysis; this group included those whose expression was common between both strains as well as unique for each strain. The proteins were identified by microLC/MS/MS of the peptides produced by an in-gel tryptic digestion and compared to translated data from the Pseudomonas Genome Project; optimization of this technique has allowed for the comparison of proteins expressed by strains 383 and 2192.

  6. Solid-phase extraction of polar hydrophilic aromatic sulfonates followed by capillary zone electrophoresis-UV absorbance detection and ion-pair liquid chromatography-diode array UV detection and electrospray mass spectrometry.

    PubMed

    Loos, R; Alonso, M C; Barceló, D

    2000-08-25

    A comprehensive comparison of four different polymeric solid-phase extraction (SPE) materials for the extraction of 22 different aromatic sulfonates of environmental concern was performed. The investigated adsorbents were the polystyrene-divinylbenzene materials LiChrolut EN from Merck, Isolute ENV+ from International Sorbent Technology, HR-P from Macherey-Nagel and the new Oasis HLB poly(divinylbenzene-co-N-vinylpyrrolidone) copolymer from Waters. Different SPE parameters like the elution solvent and the drying step of the cartridges were optimized. Analyses were performed by capillary zone electrophoresis-UV absorbance detection (CZE-UV) and ion-pair liquid chromatography-diode array UV detection coupled in series with electrospray mass spectrometry (IP-LC-DAD-ESI-MS) in the negative ionization mode. LC-MS offers a higher separation efficiency than CZE. The best adsorbents were LiChrolut EN and HR-P followed by Isolute ENV+ and Oasis HLB. The recoveries for most of the onefold negatively charged aromatic sulfonates were >50% for the extraction from spiked ground water at 50 microg/l. Recoveries for LiChrolut EN and HR-P were approximately 20% higher than for Isolute ENV+. Very hydrophilic sulfonates containing more than one negative sulfonate group could not be extracted by any of the tested adsorbents.

  7. Sensitive determination of midazolam and identification of its two metabolites in human body fluids by column-switching capillary high-performance liquid chromatography/fast atom bombardment-mass spectrometry.

    PubMed

    Sano, T; Sato, K; Kurihara, R; Mizuno, Y; Kojima, T; Yamakawa, Y; Yamada, T; Ishii, A; Katsumata, Y

    2001-09-01

    Midazolam is a benzodiazepine and is widely prescribed for preanesthesia or general anesthesia. Overdose or intoxication cases of midazolam have been reported. In Japan, smuggled midazolam tablets could be involved in some criminal cases. Midazolam and its two metabolites were extracted by the solid-phase extraction method using Bond Elut SCX cartridges. The compounds were analyzed by on-line capillary high-performance liquid chromatography/fast atom bombardment-mass spectrometry. Midazolam and its two metabolites were well separated on the chromatogram, and each mass spectra gave [M+H](+) ion as a base peak. Deuterium-labeled midazolam was synthesized as an internal standard; it has enabled precise and reproducible quantitation of midazolam in blood samples. The calibration curve showed excellent linearity in the range of 2-200 ng/ml in spiked serum. The detection limit was 300 pg/ml (signal-to-noise ratio=3). The whole blood and urine samples from the victim of a homicide case were analyzed, and the midazolam concentration in the whole blood was estimated to be 163 ng/ml. The present method should be useful in clinical and forensic toxicology, because of its high sensitivity and specificity.

  8. Characterization of non-discriminating tetramethylammonium hydroxide-induced thermochemolysis-capillary gas chromatography-mass spectrometry as a method for profiling fatty acids in bacterial biomasses.

    PubMed

    Poerschmann, Juergen; Parsi, Ziba; Górecki, Tadeusz; Augustin, Juergen

    2005-04-15

    Thermochemolysis using tetramethylammonium hydroxide (TMAH) as a method for profiling fatty acids (FAs) as methyl esters (FAMEs) was studied with respect to discrimination of bacterial fatty acid patterns in Gram-negative Pseudomonas putida in comparison with patterns obtained by classical preparation schemes (pressurized solvent extraction, alkaline saponification). A new, non-discriminating pyrolysis approach was used in these experiments. In this method, pyrolysis is carried out inside a deactivated stainless steel capillary constituting a part of the column train. This approach made it possible to distinguish analyte discrimination brought about by (i) the pyrolyzer set-up in conventional pyrolysis and (ii) chemical thermochemolysis reaction itself. Our results showed no significant discrimination for saturated, monounsaturated and cyclopropane FAs when using thermochemolysis temperatures up to 550 degrees C with the non-discriminating, capacitive-discharged based approach. Likewise, the cis/trans ratio of monounsaturated FAs was preserved. This is in sharp contrast to conventional pyrolysis systems (both Curie-point or flash pyrolyzers) using much longer thermochemolysis times. When using these systems, artificial monounsaturated FAMEs were formed during heat treatment resulting in biased species identification/classification. Hydroxy-FAs, chiefly bound covalently in lipopolysaccharides, could be almost quantitatively liberated by TMAH using non-discriminating pyrolysis (beyond 90%), whereas the recoveries were lower with conventional approaches. The new method makes it possible to profile fatty acids in very small amounts of both solid and liquid samples without significant sample preparation. This was exemplified by the results of TMAH-thermochemolysis of a fermentation broth taken from an in situ bioremediation reactor to monitor enhanced natural attenuation processes, and tomato roots which were subjected to cellulolytic bacteria attacks (Streptomyces

  9. Profiling of cis-Diol-containing Nucleosides and Ribosylated Metabolites by Boronate-affinity Organic-silica Hybrid Monolithic Capillary Liquid Chromatography/Mass Spectrometry

    PubMed Central

    Jiang, Han-Peng; Qi, Chu-Bo; Chu, Jie-Mei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-01-01

    RNA contains a large number of modified nucleosides. In the metabolic re-exchange of RNA, modified nucleosides cannot be recycled and are thus excreted from cells into biological fluids. Determination of endogenous modified nucleosides in biological fluids may serve as non-invasive cancers diagnostic methods. Here we prepared boronate-affinity organic-silica hybrid capillary monolithic column (BOHCMC) that exhibited excellent selectivity toward the cis-diol-containing compounds. We then used the prepared BOHCMC as the on-line solid-phase microextraction (SPME) column and developed an on-line SPME-LC-MS/MS method to comprehensively profile cis-diol-containing nucleosides and ribosylated metabolites in human urine. Forty-five cis-diol-containing nucleosides and ribosylated metabolites were successfully identified in human urine. And five ribose conjugates, for the first time, were identified existence in human urine in the current study. Furthermore, the relative quantification suggested 4 cis-diol-containing compounds (5′-deoxy-5′-methylthioadensine, N4-acetylcytidine, 1-ribosyl-N-propionylhistamine and N2,N2,7-trimethylguanosine) increased more than 1.5 folds in all the 3 types of examined cancers (lung cancer, colorectal cancer, and nasopharyngeal cancer) compared to healthy controls. The on-line SPME-LC-MS/MS method demonstrates a promising method for the comprehensive profiling of cis-diol-containing ribose conjugates in human urines, which provides an efficient strategy for the identification and discovery of biomarkers and may be used for the screening of cancers. PMID:25585609

  10. Capillary muscle

    PubMed Central

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-01-01

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This “hyperbolic” force–velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136–195]. Hill’s heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973–976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971–973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318; Deshcherevskiĭ VI (1968) Biofizika 13(5):928–935]. Here, we develop a capillary analog of the sarcomere obeying Hill’s equation and discuss its analogy with muscles. PMID:25944938

  11. Use of non-porous reversed-phase high-performance liquid chromatography for protein profiling and isolation of proteins induced by temperature variations for Siberian permafrost bacteria with identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and capillary electrophoresis-electrospray ionization mass spectrometry.

    PubMed

    Chong, B E; Kim, J; Lubman, D M; Tiedje, J M; Kathariou, S

    2000-10-01

    Non-porous reversed-phase high-performance liquid chromatography (NP-RP-HPLC) has been used to separate and isolate proteins from whole cell lysates of ED 7-3, a bacterium from the buried Siberian permafrost sediment. The proteins collected from the liquid eluent of this separation were then analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS). In order to study the differences in expression of cold-shock proteins (CSPs) at different growth temperatures, cultures of the ED 7-3 strain were prepared at 4 degrees C and 25 degrees C. The goals of this work were twofold: firstly, to identify the presence of CSPs and other proteins that are highly expressed at 4 degrees C but not at 25 degrees C; and secondly, to isolate these proteins for MALDI-TOF-MS and CE-ESI-MS identification. In this initial work, distinct protein profiles were observed for these cultures as a function of temperature. Fraction collection from the eluent of NP-RP-HPLC of some of the highly expressed proteins was performed and the proteins were mass analyzed for molecular mass. Peptide maps of the proteins were generated by tryptic digestion and were analyzed by CE-ESI-MS and MALDI-TOF-MS for database identification of the expressed proteins.

  12. Use of MEDUSA-based data analysis and capillary HPLC-ion-trap mass spectrometry to examine complex immunoaffinity extracts of RBAp48.

    PubMed

    Gururaja, Tarikere; Li, Weiqun; Bernstein, Jim; Payan, Donald G; Anderson, D C

    2002-01-01

    To examine the Jurkat cell interaction partners of RbAp48, we digested entire immunoaffinity extracts with trypsin and identified potential interacting proteins using one- and two-dimensional microcapillary HPLC-ion-trap mass spectrometry. An Oracle-based automated data analysis system (MEDUSA) was used to compare quadruplicate anti-RbAp48 antibody affinity extracts with two sets of quadruplicate control extracts. The anti-RbAp48 extracts contained over 40 difference 1D gel bands. We identified all known proteins of the NuRD/Mi-2 complex including human p66. Three potential homologues of members of this complex were also found, suggesting that there may be more than one variant of this complex. Eleven proteins associated with RNA binding or pre-mRNA splicing were observed. Four other proteins, including a putative tumor suppressor, were identified, as were 18 ribosomal proteins. There was little overlap with RbAp48-interacting proteins defined by yeast two-hybrid methods. These results demonstrate the analysis of a complex immunoaffinity extract and suggest a more complex cellular role for RbAp48 than previously documented.

  13. On-line two-dimensional capillary strong anion exchange/reversed phase liquid chromatography-tandem mass spectrometry for comprehensive lipid analysis.

    PubMed

    Bang, Dae Young; Moon, Myeong Hee

    2013-10-04

    An on-line two-dimensional liquid chromatography method was developed for comprehensive lipid profiling by coupling strong anion exchange (SAX) and nanoflow reversed-phase liquid chromatography (nRPLC) prior to electrospray ionization-tandem mass spectrometry (2D-SAX/nRPLC-ESI-MS/MS). Lipids can be classified into four different types according to the electrical propensities of the lipids: anionic, weak anionic, neutral polar, and special lipids. In 2D-SAX/nRPLC, various lipids can be fractionated in the first dimension (SAX: 5 μm to 100 Å, 5.0 cm × 75 μm i.d.) by step elution (methanol and salt solution), followed by the molecular separation of lipids in the second dimension (RP: 3 μm to 100 Å, 7.0 cm × 75 μm i.d.) with binary gradient LC. Since the elution of lipids from SAX can be achieved with a very small volume of eluent delivered from an autosampler, it can be simply implemented with an LC-ESI-MS instrument for full automation, and the salt step elution, including the two-step injection procedure, can be used for the selective analysis of the desired lipid fraction. For nRPLC-ESI-MS/MS run in either positive or negative ion mode, a common ionization modifier (0.05% ammonium hydroxide with 5mM ammonium formate) was introduced into the binary mobile phase solutions so that 2D-LC-MS could be operated in both ion modes without changing the mobile phase solutions. The developed on-line 2D-SAX/nRPLC-ESI-MS/MS was evaluated with 22 different standard lipids for the optimization of the salt step elution and was applied to a healthy human plasma lipid extract, resulting in the identification of a total of 303 plasma lipids, including 14 different classes.

  14. Technical, bioinformatical and statistical aspects of liquid chromatography-mass spectrometry (LC-MS) and capillary electrophoresis-mass spectrometry (CE-MS) based clinical proteomics: a critical assessment.

    PubMed

    Dakna, Mohammed; He, Zengyou; Yu, Wei Chuan; Mischak, Harald; Kolch, Walter

    2009-05-01

    The search for biomarkers in biological fluids that can be used for disease diagnosis and prognosis using mass spectrometry has emerged to become a state-of-the-art methodology for clinical proteomics. Poor cross platform comparison of the findings, however, makes the need for comparison studies probably as urgent as the need for new ones. It is now increasingly recognized that standardized statistical and bioinformatics approaches during data processing are of utmost importance for such comparisons. This paper reviews two of the currently most promising methods, namely LC-MS and CE-MS techniques, and software tools used to analyze the huge amount of data they generate. We further review the statistical issues of feature selection and sample classification.

  15. Conventional and narrow bore short capillary columns with cyclodextrin derivatives as chiral selectors to speed-up enantioselective gas chromatography and enantioselective gas chromatography-mass spectrometry analyses.

    PubMed

    Bicchi, Carlo; Liberto, Erica; Cagliero, Cecilia; Cordero, Chiara; Sgorbini, Barbara; Rubiolo, Patrizia

    2008-11-28

    The analysis of complex real-world samples of vegetable origin requires rapid and accurate routine methods, enabling laboratories to increase sample throughput and productivity while reducing analysis costs. This study examines shortening enantioselective-GC (ES-GC) analysis time following the approaches used in fast GC. ES-GC separations are due to a weak enantiomer-CD host-guest interaction and the separation is thermodynamically driven and strongly influenced by temperature. As a consequence, fast temperature rates can interfere with enantiomeric discrimination; thus the use of short and/or narrow bore columns is a possible approach to speeding-up ES-GC analyses. The performance of ES-GC with a conventional inner diameter (I.D.) column (25 m length x 0.25 mm I.D., 0.15 microm and 0.25 microm d(f)) coated with 30% of 2,3-di-O-ethyl-6-O-tert-butyldimethylsilyl-beta-cyclodextrin in PS-086 is compared to those of conventional I.D. short column (5m length x 0.25 mm I.D., 0.15 microm d(f)) and of different length narrow bore columns (1, 2, 5 and 10 m long x 0.10 mm I.D., 0.10 microm d(f)) in analysing racemate standards of pesticides and in the flavour and fragrance field and real-world-samples. Short conventional I.D. columns gave shorter analysis time and comparable or lower resolutions with the racemate standards, depending mainly on analyte volatility. Narrow-bore columns were tested under different analysis conditions; they provided shorter analysis time and resolutions comparable to those of conventional I.D. ES columns. The narrow-bore columns offering the most effective compromise between separation efficiency and analysis time are the 5 and 2m columns; in combination with mass spectrometry as detector, applied to lavender and bergamot essential oil analyses, these reduced analysis time by a factor of at least three while separation of chiral markers remained unaltered.

  16. Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Determination of Wastewater Compounds by Polystyrene-Divinylbenzene Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry

    USGS Publications Warehouse

    Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.; Barber, Larry B.; Burkhardt, Mark R.

    2002-01-01

    A method for the determination of 67 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals in wastewater on aquatic organisms. This method also may be useful for evaluating the impact of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are an indicator of wastewater or that have been chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclicaromatic hydrocarbons, and high-use domestic pesticides. Water samples are filtered to remove suspended particulate matter and then are extracted by vacuum through disposable solid-phase cartridges that contain polystyrene-divinylbenzene resin. Cartridges are dried with nitrogen gas, and then sorbed compounds are eluted with dichloromethane-diethyl ether (4:1) and determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 4 micrograms per liter averaged 74 percent ? 7 percent relative standard deviation for all method compounds. Initial method detection limits for single-component compounds (excluding hormones and sterols) averaged 0.15 microgram per liter. Samples are preserved by filtration, the addition of 60 grams NaCl, and storage at 4 degrees Celsius. The laboratory has established a sample-holding time (prior to sample extraction) of 14 days from the date of sample collection until a statistically accepted method can be used to determine the effectiveness of these sample-preservation procedures.

  17. Capillary liquid chromatography-microcoil 1H nuclear magnetic resonance spectroscopy and liquid chromatography-ion trap mass spectrometry for on-line structure elucidation of isoflavones in Radix astragali.

    PubMed

    Xiao, H B; Krucker, M; Putzbach, K; Albert, K

    2005-03-04

    Miniaturization and hyphenation of chromatographic separation techniques to nuclear magnetic resonance spectroscopy is being increasingly demanded in the field of biomedical, drug metabolite and natural product analysis. Herein, capillary liquid chromatography was coupled on-line to microcoil 1H nuclear magnetic resonance spectroscopy (capLC-NMR) equipped with a 1.5 microL solenoidal probe for structure elucidation of isoflavones in Radix astragali. The extract was screened by HPLC-UV-MS as the preliminary step and four major peaks were identified tentatively by ion trap mass spectrometry molecular weights and characteristic fragments. Then, stopped-flow capLC-UV-NMR was performed using 33 microg extract injected on-column. The four peaks were parked manually in the micro probe one by one and corresponding 1H NMR spectra were recorded with good resolutions under the applied capLC-NMR conditions (120 and 220 ng injected on-column for peaks 2 and 4, respectively). All aromatic regions of 1H NMR spectra correlated well to the characteristic signals of isoflavone aglycone protons. And the signal corresponding to the anomeric proton of the glucopyranoside of isoflavone glycoside was also obtained for peak 1. Therefore, these four peaks are determined as calycosin-7-O-beta-D-glucopyranoside (1), ononin (2), calycosin (3) and formononetin (4) unambiguously. The capLC-NMR results indicate that this hyphenated technique could be used for the determination of a great variety of natural products from small sample amounts, e.g., only 5 g R. astragali in this study.

  18. Detection of fenspiride and identification of in vivo metabolites in horse body fluids by capillary gas chromatography-mass spectrometry: administration, biotransformation and urinary excretion after a single oral dose.

    PubMed

    Dumasia, M C; Houghton, E; Hyde, W; Greulich, D; Nelson, T; Peterson, Jackie

    2002-02-05

    Studies related to the in vivo biotransforrmation and urinary excretion of fenspiride hydrochloride in the horse are described. After oral administration, the drug is metabolised by both phase I functionalisation and phase II conjugation pathways. Following enzymatic deconjugation, fenspiride and its phase I metabolites were isolated from post-administration biofluids using bonded co-polymeric mixed mode solid-phase extraction cartridges to isolate the basic compounds. Following trimethylsilylation (TMS), the parent drug and metabolites were identified by capillary gas chromatography-mass spectrometry (GC-MS). Fenspiride (A) and seven metabolites (B-->G) arising from oxidation on both the aromatic and heterocyclic substructures were detected in urine. The positive ion electron ionisation mass spectra of the TMS derivatives of fenspiride and its metabolites provided useful information on its metabolism. Positive ion methane chemical ionisation-GC-MS of the derivatives provided both derivatised molecular mass and structural information. Unchanged fenspiride can be detected in post-administration plasma and urine samples for up to 24 h. Maximum urinary levels of 100-200 ng ml(-1) were observed between 3 and 5 h after administration. After enzymatic deconjugation, the major phenolic metabolite (G) can be detected in urine for up to 72 h. This metabolite is the analyte of choice in the GC-MS screening of post-race equine urine samples for detection of fenspiride use. However, a distinct difference was observed in the urinary excretion of this metabolite between the thoroughbred horses used in UK study and the quarterbred and standardbred horses used for the USA administrations.

  19. Identification of V-type nerve agents in vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator and fluoridating conversion tube.

    PubMed

    Ohrui, Y; Nagoya, T; Kurimata, N; Sodeyama, M; Seto, Y

    2017-07-01

    A field-portable gas chromatography-mass spectrometry (GC-MS) system (Hapsite ER) was evaluated for the detection of nonvolatile V-type nerve agents (VX and Russian VX (RVX)) in the vapor phase. The Hapsite ER system consists of a Tri-Bed concentrator gas sampler, a nonpolar low thermal-mass capillary GC column and a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump. The GC-MS system was attached to a VX-G fluoridating conversion tube containing silver nitrate and potassium fluoride. Sample vapors of VX and RVX were converted into O-ethyl methylphosphonofluoridate (EtGB) and O-isobutyl methylphosphonofluoridate (iBuGB), respectively. These fluoridated derivatives were detected within 10 min. No compounds were detected when the VX and RVX samples were analyzed without the conversion tube. A vapor sample of tabun (GA) was analyzed, in which GA and O-ethyl N,N-dimethylphosphoramidofluoridate were detected. The molar recovery percentages of EtGB and iBuGB from VX and RVX vapors varied from 0.3 to 17%, which was attributed to variations in the vaporization efficiency of the glass vapor container. The conversion efficiencies of the VX-G conversion tube for VX and RVX to their phosphonate derivatives were estimated to be 40%. VX and RVX vapors were detected at concentrations as low as 0.3 mg m(-3) . Gasoline vapor was found to interfere with the analyses of VX and RVX. In the presence of 160 mg m(-3) gasoline, the detection limits of VX and RVX vapor were increased to 20 mg m(-3) . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. 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. Copyright © 2016

  1. New strategies to screen for endocrine-disrupting chemicals in the Portuguese marine environment utilizing large volume injection-capillary gas chromatography-mass spectrometry combined with retention time locking libraries (LVI-GC-MS-RTL).

    PubMed

    Almeida, C; Serôdio, P; Florêncio, M H; Nogueira, J M F

    2007-04-01

    A new analytical strategy to screen for endocrine-disrupting chemicals (EDCs) in environmental matrices is presented. The strategy uses solid-phase extraction followed by large volume injection and capillary gas chromatography coupled to mass spectrometry combined with retention time locking libraries (SPE-LVI-GC-MS-RTL). Characterization of the proposed methodology (SPE-LVI-GC-MS) for selected classes of EDCs enabled high reproducibility and robustness at the ultratrace level. The RTL databases used allowed hundreds of non-target semivolatiles (i.e., pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls and other classes of suspected EDCs from a great number of unknown environmental matrices) to be simultaneously screened for in an easy, fast and remarkable manner. The application of the proposed methodology to real environmental samples demonstrated its remarkable selectivity and sensitivity at the ultratrace level. Screening assessments performed on water and sediment matrices from eight Portuguese estuaries and coastal waters identified EDC "hotspots." These EDCs mainly come from agricultural and a wide variety of industrial sources, and include pesticides and pesticide metabolites, phenolic derivatives and polycyclic aromatic hydrocarbons, which are included in the lists of priority substances published by international environmental agencies. The estuaries that contained relatively high levels of pesticides were Guadiana, Sado and Mondego, while Minho, Douro and Formosa showed enhanced levels of phenolic derivatives. Dibutyltin and tributyltin, selected as target compounds to be monitored by SPE-LVI-GC-MS in the selected ion monitoring mode, were shown to be widespread contaminants at trace levels in almost all of the sediment matrices assessed. The reliability of the proposed methodology undoubtedly makes it a valuable tool that could replace other analytical strategies currently used to screen for EDCs present in the environment at

  2. Capillary electrophoresis of carbohydrates.

    PubMed

    Oefner, P J; Chiesa, C

    1994-08-01

    Capillary electrophoresis has emerged as a highly promising technique for the analysis of mono- and oligosaccharides. The approaches developed for overcoming the lack of chromophoric and fluorophoric functions in most carbohydrates involve the use of indirect photometric detection, amperometry, mass spectrometry, and precolumn derivatization with various tags. The merits and drawbacks of the derivatizing agents, including 2-aminopyridine, 4-amino-benzoic acid and its analogues, which for the first time permitted the reproducible determination of aldoses, uronic acids and even ketoses in the low femtomole range by means of readily available UV detection, and other agents such as 8-aminonaphthalene-1,3,6-trisulphonic acid, 1-phenyl-3-methyl-5-pyrazolone and 3-(4-carboxybenzoyl)-2-quinoline-carboxaldehyde, are discussed in detail. Means to secure electromigration of the usually neutral carbohydrates are: (i) ionization of hydroxyl groups at high pH; (ii) complexation of vicinal or alternate hydroxyl groups with borate or other charged compounds such as alkaline earth metal ions; (iii) derivatization with a reagent possessing ionizable functions; and (iv) partitioning into a pseudostationary phase such as sodium dodecyl sulphate micelles. Each alternative has its own analytical rewards, and combinations of the above mechanisms allow the two-dimensional and perhaps even three-dimensional mapping of oligosaccharides. Pyridylaminated oligosaccharides, for instance, have been separated both according to size by exploiting differences in the charge-to-mass ratio, with the charge being identical for each oligomer under acidic conditions due to protonation of the imino group incorporated by precolumn derivatization, as well as on the basis of structural differences, as a consequence of differences in the ease of borate complexation of the peripheral monosaccharide residues. It is also shown that the 4-aminobenzonitrile derivatives of mono- and disaccharides can be separated

  3. Efficient organic monoliths prepared by γ-radiation induced polymerization in the evaluation of histone deacetylase inhibitors by capillary(nano)-high performance liquid chromatography and ion trap mass spectrometry.

    PubMed

    Badaloni, Elena; Barbarino, Marcella; Cabri, Walter; D'Acquarica, Ilaria; Forte, Michela; Gasparrini, Francesco; Giorgi, Fabrizio; Pierini, Marco; Simone, Patrizia; Ursini, Ornella; Villani, Claudio

    2011-06-24

    New monolithic HPLC columns were prepared by γ-radiation-triggered polymerization of hexyl methacrylate and ethylene glycol dimethacrylate monomers in the presence of porogenic solvents. Polymerization was carried out directly within capillary (250-200 μm I.D.) and nano (100-75 μm I.D.) fused-silica tubes yielding highly efficient columns for cap(nano)-LC applications. The columns were applied in the complete separation of core (H2A, H2B, H3, and H4) and linker (H1) histones under gradient elution with UV and/or electrospray ionization (ESI) ion trap mass spectrometry (MS) detections. Large selectivity towards H1, H2A-1, H2A-2, H2B, H3-1, H3-2 and H4 histones and complete separation were obtained within 8 min time windows, using fast gradients and very high linear flow velocities, up to 11 mm/s for high throughput applications. The method developed was the basis of a simple and efficient protocol for the evaluation of post-translational modifications (PTMs) of histones from NCI-H460 human non-small-cell lung cancer (NSCLC) and HCT-116 human colorectal carcinoma cells. The study was extended to monitoring the level of histone acetylation after inhibition of Histone DeACetylase (HDAC) enzymes with suberoylanilide hydroxamic acid (SAHA), the first HDAC inhibitor approved by the FDA for cancer therapy. Attractive features of our cap(nano)-LC/MS approach are the short analysis time, the minute amount of sample required to complete the whole procedure and the stability of the polymethacrylate-based columns. A lab-made software package ClustMass was ad hoc developed and used to elaborate deconvoluted mass spectral data (aligning, averaging, clustering) and calculate the potency of HDAC inhibitors, expressed through a Relative half maximal Inhibitory Concentration parameter, namely R_IC(50) and an averaged acetylation degree. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1995-08-08

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

  5. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1995-01-01

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibres to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands.

  6. Intranasal lobular capillary haemangioma

    PubMed Central

    Nayak, Dipak Ranjan; Bhandarkar, Ajay M; Shivamurthy, Archana; Joy, Jasmi

    2014-01-01

    Lobular capillary haemangioma (LCH) is a benign proliferation of capillaries with a characteristic lobular architecture on microscopy; it has an affinity for mucous membrane and skin of the head and neck. It is extremely rare in the nasal cavity. We present the case of a 45-year-old man who presented with epistaxis without any predisposing factors, which was diagnosed as lobular capillary haemangioma. PMID:25304675

  7. Capillary electrophoretic and mass spectrometric analysis of a polydisperse fluorosurfactant.

    PubMed

    Al-Jarah, Suhair Yousif; Sjödahl, Johan; Woldegiorgis, Andreas; Emmer, Asa

    2005-02-01

    A fluorosurfactant has been studied using capillary electrophoresis and mass spectrometry. The fluorosurfactant, FC134, can be used as a buffer additive in capillary electrophoresis in order to decrease wall adsorption of proteins and in micellar electrokinetic chromatography. However, it has been discovered that this fluorosurfactant is polydisperse, thus containing substances with different lengths and structures. In this work, the fluorosurfactant sample components were separated by capillary electrophoresis. An uncoated as well as a poly(vinyl alcohol)-coated capillary were used with running electrolytes containing methanol and acetic acid. Following the capillary electrophoretic separation, fractions were collected for further analysis by MALDI-MS. Non-fractionated samples were also analyzed both by MALDI-MS and by ESI-MS.

  8. Capillary rheometry for thermosets

    NASA Technical Reports Server (NTRS)

    Malguarnera, S. C.; Carroll, D. R.

    1982-01-01

    Capillary rheometry is effectively used with thermosets. Most important is providing a uniform temperature in the barrel. This was successfully accomplished by using a circulating hot oil system. Standard capillary rheometry methods provide the dependence of thermoset apparent viscosity on shear rate, temperature and time. Such information is very useful in evaluating resin processability and in setting preliminary fabrication conditions.

  9. Mussel-inspired polydopamine-assisted hydroxyapatite as the stationary phase for capillary electrochromatography.

    PubMed

    Zhang, Juan; Zhang, Wenpeng; Bao, Tao; Chen, Zilin

    2014-01-07

    A novel capillary with hydroxyapatite (HAP) as the stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). To immobilize HAP, a mussel-inspired polydopamine method was utilized to modify the capillary firstly, generating a polydopamine layer; and then a layer of HAP would be formed on the polydopamine layer by a biomineralization process, to produce a HAP-modified capillary (HAP@capillary). Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) provided evidence of nanostructured HAP grown on the surface of the capillary wall. The electroosmotic flow (EOF) characteristic of the HAP@capillary was investigated by varying the percentage of acetonitrile and pH value of the buffer with thiourea as a marker, and a pH-dependent EOF from anode to cathode was observed. The HAP@capillary exhibits high column efficiency for methylbenzene, up to 151,138 plates per meter. Different kinds of compounds including alkylbenzenes, phenols and amines have been successfully separated by the HAP@capillary in CEC mode. The HAP@capillary also possessed good separation ability in capillary liquid chromatography (CLC) mode because of the relatively large ratio of HAP in the capillary; however, the separation efficiency was not as good as that in CEC mode. The reproducibilities of the HAP@capillary were evaluated, and the relative standard deviations were found to be lower than 5%.

  10. Combining poly(dimethyldiphenylsiloxane) and nitrile phases for improving the separation and quantitation of benzalkonium chloride homologues: In-tube solid phase microextraction-capillary liquid chromatography-diode array detection-mass spectrometry for analyzing industrial samples.

    PubMed

    Prieto-Blanco, M C; Moliner-Martinez, Y; Campíns-Falcó, P

    2013-07-05

    The retention and separation of four homologues of benzalkonium chloride (alkyl (C12, C14, C16, C18) dimethylbenzylammonium chloride) have been studied in poly(dimethyldiphenylsiloxane) (TRB) and nitrile capillary phases, respectively. Under the optimized conditions (50% acetonitrile in processed samples, 35% of diphenyl content of the TRB, capillary length 43cm and water:methanol 60:40 as replacing solvent), the extraction efficiency was similar for all the homologues with satisfactory reproducibility and independently of the amount and proportion of homologues. Industrial samples with high viscosity or with complex composition and washes waters have been analyzed without previous treatment. The coupling of IT-SPME-CapLC-DAD to MS detection allowed the determination of the minority homologues (C16 and C18) in the industrial samples and washes waters. No matrix effect was found.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Capillary rise of superspreaders.

    PubMed

    Radulovic, Jovana; Sefiane, Khellil; Shanahan, Martin E R

    2011-09-15

    Trisiloxane surfactants, known as 'superspreaders', are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get further insight into their interfacial activity. Additionally, our knowledge of the capillary rise of superspreaders is surprisingly limited, and the effect of this extraordinary group of surfactants on capillary phenomena has been largely overlooked. Diffusion was confirmed to be the limiting factor of trisiloxane behaviour. A tentative theoretical explanation for the phenomenon studied and an appropriate mathematical model are presented. It is concluded that the enhancement of wetting due to surfactant addition is also a function of geometry: the effect is clear for a sessile drop, but more complex and less beneficial in a capillary.

  16. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1982-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  17. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1984-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  18. Capillary nail refill test

    MedlinePlus

    ... may indicate: Dehydration Shock Peripheral vascular disease (PVD) Hypothermia Alternative Names Nail blanch test; Capillary refill time ... Elsevier Saunders; 2016:chap 79. Read More Dehydration Hypothermia Peripheral artery disease - legs Shock Review Date 4/ ...

  19. Capillary saturation and desaturation

    NASA Astrophysics Data System (ADS)

    Hilfer, R.; Armstrong, R. T.; Berg, S.; Georgiadis, A.; Ott, H.

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  20. Capillary discharge source

    DOEpatents

    Bender, III, Howard Albert

    2003-11-25

    Debris generation from an EUV electric discharge plasma source device can be significantly reduced or essentially eliminated by encasing the electrodes with dielectric or electrically insulating material so that the electrodes are shielded from the plasma, and additionally by providing a path for the radiation to exit wherein the electrodes are not exposed to the area where the radiation is collected. The device includes: (a) a body, which is made of an electrically insulating material, that defines a capillary bore that has a proximal end and a distal end and that defines at least one radiation exit; (b) a first electrode that defines a first channel that has a first inlet end that is connected to a source of gas and a first outlet end that is in communication with the capillary bore, wherein the first electrode is positioned at the distal end of the capillary bore; (c) a second electrode that defines a second channel that has a second inlet end that is in communication with the capillary bore and an outlet end, wherein the second electrode is positioned at the proximal end of the capillary bore; and (d) a source of electric potential that is connected across the first and second electrodes, wherein radiation generated within the capillary bore is emitted through the at least one radiation exit and wherein the first electrode and second electrode are shielded from the emitted radiation.

  1. Capillary saturation and desaturation.

    PubMed

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  2. Recent developments and applications of capillary and microchip electrophoresis in proteomic and peptidomic analyses.

    PubMed

    Štěpánová, Sille; Kašička, Václav

    2016-01-01

    This review presents recent developments and applications of capillary and microchip electromigration methods in proteomics and peptidomics. Sample preparation methods as well as instrumental innovations in the coupling of these advanced electromigration methods with mass spectrometry detection employed in proteomic and peptidomic analyses are presented. Interesting applications of various capillary electromigration methods in bottom-up as well as top-down proteomics, including investigation of post-translational modifications of proteins are described. In addition, several examples of the use of capillary electromigration methods combined with mass spectrometry detection in clinical proteomics and peptidomics are demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Improved tryptic digestion assisted with an acid-labile anionic surfactant for the separation and characterization of glycopeptide glycoforms of a proteolytic-resistant glycoprotein by capillary electrophoresis time-of-flight mass spectrometry.

    PubMed

    Barroso, Albert; Giménez, Estela; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

    2016-04-01

    Certain glycoproteins are rather difficult to digest due to compacted tertiary or quaternary structures. In a previous study, a capillary LC coupled to TOF-MS (μLC-TOF-MS) method was developed for the detection and characterization of the glycopeptide glycoforms of human transferrin (Tf), a proteolytic resistant glycoprotein, in serum samples. After immunoaffinity purification, Tf was digested with trypsin in the presence of RapiGest(®) and μLC-TOF-MS analyses permitted to detect the N413 and N611 glycopeptide glycoforms. Conversely, the use of this surfactant, albeit mandatory to quantitatively digest the isolated Tf, proved detrimental to CE-TOF-MS analysis due to its interaction with the inner surface of the silica capillary walls. As CE is usually regarded as an interesting alternative to other separation techniques (low consumption of reagents, excellent separation efficiency, and reduced analysis times), in this work, the undesirable interferences of the surfactant have been removed to allow the correct separation and detection of Tf glycoforms by CE-TOF-MS. Moreover, the digestion protocol described by the RapiGest(®) manufacturer has been modified to minimize desialylation of Tf glycopeptide glycoforms. The new developed CE-TOF-MS methodology has been then compared with the former μLC-TOF-MS by means of sensitivity and separation efficiency of Tf glycopeptide glycoforms in the standard glycoprotein. Additionally, Tf glycopeptide glycoforms from serum of healthy volunteers and patients with congenital disorders of glycosylation have also been analyzed following the developed methodology.

  4. Gas-Filled Capillary Model

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  5. 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).

  6. Capillary condenser/evaporator

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A. (Inventor)

    2010-01-01

    A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

  7. Capillary Structures for Exploration Life Support (Capillary Structures)

    NASA Image and Video Library

    2017-07-10

    iss052e013146 (July 10, 2017) --- Astronaut Jack Fischer is photographed during setup of hardware for the Capillary Structures for Exploration Life Support (Capillary Structures) two sorbent demonstrations. The Capillary Structures for Exploration Life Support (Capillary Structures) investigation studies a new method using structures of specific shapes to manage fluid and gas mixtures. The investigation studies water recycling and carbon dioxide removal, benefiting future efforts to design lightweight, more reliable life support systems for future space missions.

  8. Capillary action liquid chromatography.

    PubMed

    Zhang, Bo; Bergström, Edmund T; Goodall, David M; Myers, Peter

    2009-06-01

    Capillary action LC (caLC) is introduced as a technique using capillary action as the driving force to perform LC in capillary columns packed with HPLC type microparticulate materials. A dry packing method with centrifugal force was developed to prepare capillary columns in parallel (10 columns per 3 min) to support their disposable use in caLC. Using a digital microscope for real-time imaging and recording separations of components in a dye mixture, caLC was found to have flow characteristics similar to TLC. Based on the investigation of microparticulate HPLC silica gels of different size (1.5-10 microm) and a typical TLC grade irregular medium, Merck 60G silica, the van Deemter curves suggested molecular diffusion as the major contribution to band broadening in caLC. With Waters Xbridge 2.6 microm silica, plate heights down to 8.8 microm were obtained, comparable to those achievable in HPLC. Assisted by an image-processing method, the visual caLC separation was converted to a classical chromatogram for further data analysis and such a facility confirmed the observation of highly efficient bands.

  9. Capillary blood glucose monitoring.

    PubMed

    Wallymahmed, M

    This article, the first in a series of articles relating to clinical skills in nursing, outlines the procedure of capillary blood glucose monitoring. This is a convenient way of monitoring blood glucose patterns and can be a useful aid in guiding treatment changes in patients with type 1 and type 2 diabetes, especially during periods of illness or frequent hypoglycaemia.

  10. Improved accuracy in the determination of polycyclic aromatic hydrocarbons in air using 24 h sampling on a mixed bed followed by thermal desorption capillary gas chromatography-mass spectrometry.

    PubMed

    Wauters, Eric; Van Caeter, Peter; Desmet, Gilbert; David, Frank; Devos, Christophe; Sandra, Pat

    2008-05-09

    A new sampling method for the determination of polycyclic aromatic hydrocarbons (PAHs) in ambient air is described. The method is based on active sampling on sorption tubes consisting of polydimethylsiloxane (PDMS) foam, PDMS particles and a TENAX TA bed. After sampling, the solutes are quantitatively recovered by thermal desorption and analysed by capillary GC-MS. The new sampling method has been compared to the classical method using high-volume sampling on a glass fiber filter followed by polyurethane foam for 24h sampling of ambient air. Volumes enriched were 144 l on the mixed bed and 1296 m3 with the classical method. The concentrations measured using the new method were significantly higher that the values obtained using the classical method, i.e. a factor 1.2-3 for the high molecular weight PAHs and up to 35 times for naphthalene and 23 times for acenaphthene. The total toxicity equivalence value (TEQ) for PAHs was ca. two times higher compared to the conventional method, illustrating that the concentrations of PAHs in ambient air have been underestimated until now. Some figures of merit (mean value for 17 PAHs) of the method are repeatability 7.4%, detection limit 13 pg/m3, accuracy 105.6% and linearity 0.996. The method also opens interesting perspectives for the determination of other semi-volatile persistent organic pollutants (POPs) in air as illustrated with the analysis of polychlorinated biphenyls (PCBs) at a workplace during removal of transformer oil.

  11. Capillary-Channeled Polymer (C-CP) Fibers as a Stationary Phase for Sample Clean-Up of Protein Solutions for Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Manard, Benjamin T.; Marcus, R. Kenneth

    2012-08-01

    Capillary-channeled polymer (C-CP) fibers are employed in a micropipette tip format to affect a stationary phase for the solid phase extraction (SPE) of proteins from buffer solutions prior to MALDI-MS analysis. Proteins readily adsorb to the polypropylene (PP) C-CP fibers while buffer species are easily washed off the tips using DI-H2O. Elution of the solutes is achieved with an aliquot of 50:50 ACN:H2O, which is compatible with the subsequent spotting on the MALDI target with the matrix solution. Lysozyme and cytochrome c are used as test species, with a primary buffer composition of 100 mM Tris-HCl. In this case, direct MALDI-MS produces no discernible protein signals. SPE on the C-CP fibers yields high fidelity mass spectra for 1 μL sample volumes. Limits of detection for cytochrome c in 100 mM Tris-HCl are on the order of 40 nM. Extraction of cytochrome c from buffer concentrations of up to 1 M Tris-HCl, provides signal recoveries that are suppressed by only ~50 % versus neat protein solutions. Finally, extraction of 3.1 μM cytochrome c from a synthetic urine matrix exhibits excellent recovery.

  12. Study on the chiral recognition of the enantiomers of ephedrine derivatives with neutral and sulfated heptakis(2,3-O-diacetyl)-beta-cyclodextrins using capillary electrophoresis, UV, nuclear magnetic resonance spectroscopy and mass spectrometry.

    PubMed

    Hellriegel, C; Händel, H; Wedig, M; Steinhauer, S; Sörgel, F; Albert, K; Holzgrabe, U

    2001-04-20

    The enantiomers of methylephedrine, pseudoephedrine and ephedrine showed a different migration behavior in capillary electrophoresis in the presence of beta-cyclodextrin (beta-CD), heptakis(2,3-O-diacetyl)-beta-cyclodextrin and heptakis(2,3-O-diacetyl-6-sulfato)-beta-cyclodextrin (HDAS). Utilizing UV, MS and NMR spectroscopy, in particular rotating frame Overhauser experiments, an attempt was made to elucidate the chiral recognition mechanism. In the case of the neutral CDs 1:1 complexes were formed with ephedrine and methylephedrine characterized by the inclusion of the phenyl ring in the cavity and the side chain pointing out of the wider rim. In contrast, manifold complexes were formed with HDAS, which on average are characterized by an upside down inclusion of the phenyl ring in the cavity and the side chain pointing out of the narrow rim. This complex geometry is likely be stabilized by an ion-ion interaction between the positively charged nitrogens of the ephedrine derivatives and the negative charges of HDAS. In addition, an attachment of the ligand to the outside of HDAS and other complex stoichiometries are also possible.

  13. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

  14. Method of analysis and quality-assurance practices for determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry at the U.S. Geological Survey California District Organic Chemistry Laboratory, 1996-99

    USGS Publications Warehouse

    Crepeau, Kathryn L.; Baker, Lucian M.; Kuivila, Kathryn

    2000-01-01

    A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the pesticides were eluted with three cartridge volumes of hexane:diethyl ether (1:1) solution. The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for pesticides ranged from 0.002 to 0.025 microgram per liter for 1-liter samples. Recoveries ranged from 44 to 140 percent for 25 pesticides in samples of organic-free reagent water and Sacramento-San Joaquin Delta and Suisun Bay water fortified at 0.05 and 0.50 microgram per liter. The estimated holding time for pesticides after extraction on C-8 solid-phase extraction cartridges ranged from 10 to 257 days.

  15. Capillary Isoelectric Focusing

    NASA Astrophysics Data System (ADS)

    Markuszewski, Michał J.; Bujak, Renata; Daghir, Emilia

    Capillary isoelectric focusing (CIEF) is a widespread technique for the analysis of peptides and proteins in biological samples. CIEF is used to separate mixtures of compounds on the basis of differences in their isoelectric point. Aspects of sample preparation, capillary selection, zone mobilization procedures as well as various detection modes used have been described and discussed. Moreover CIEF, coupled to various types of detection techniques (MALDI or LIF), has increasingly been applied to the analysis of variety different high-molecular compounds. CIEF is considered as a highly specific analytical method which may be routinely used in the separation of rare hemoglobin variants. In addition, the application of CIEF in proteomic field have been discussed on the examples of analyses of glycoproteins and immunoglobins due to the meaning in clinical diagnostic.

  16. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015545 (19 June 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  17. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015539 (19 June 2014) --- NASA astronaut Reid Wiseman, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  18. Enantioseparations by capillary electrochromatography.

    PubMed

    Fanali, S; Catarcini, P; Blaschke, G; Chankvetadze, B

    2001-09-01

    The review summarizes recent developments in enantioseparations by capillary electrochromatography (CEC). Selected fundamental aspects of CEC are discussed in order to stress those features which may allow the success of this technique in the competitive field of enantioseparations. In addition, the comparative characteristics of the different modes of chiral CEC and the stationary phases are presented. The effects of the characteristics of the stationary and liquid phases and operational conditions on the separation results are discussed. Finally, some future trends are briefly addressed.

  19. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015523 (19 June 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  20. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015536 (19 June 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  1. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015532 (19 June 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  2. Capillary Flow Experiment

    NASA Image and Video Library

    2014-06-19

    ISS040-E-015543 (19 June 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, conducts a session with the Capillary Flow Experiment (CFE-2) in the Harmony node of the International Space Station. CFE is a suite of fluid physics experiments that investigate how fluids behave in microgravity which could benefit water and fuel delivery systems on future spacecraft. Scientists designed the CFE-2 to study properties of fluids and bubbles inside containers with a specific 3-D geometry.

  3. Automated Parallel Capillary Electrophoretic System

    DOEpatents

    Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

    2000-02-22

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  4. Identification of chemical warfare agents from vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator.

    PubMed

    Nagashima, Hisayuki; Kondo, Tomohide; Nagoya, Tomoki; Ikeda, Toru; Kurimata, Naoko; Unoke, Shohei; Seto, Yasuo

    2015-08-07

    A field-portable gas chromatograph-mass spectrometer (Hapsite ER system) was evaluated for the detection of chemical warfare agents (CWAs) in the vapor phase. The system consisted of Tri-Bed concentrator gas sampler (trapping time: 3s(-1)min), a nonpolar low thermal-mass capillary gas chromatography column capable of raising temperatures up to 200°C, a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump for data acquisition, and a personal computer for data analysis. Sample vapors containing as little as 22μg sarin (GB), 100μg soman (GD), 210μg tabun (GA), 55μg cyclohexylsarin (GF), 4.8μg sulfur mustard, 390μg nitrogen mustard 1, 140μg of nitrogen mustard 2, 130μg nitrogen mustard 3, 120μg of 2-chloroacetophenone and 990μg of chloropicrin per cubic meter could be confirmed after Tri-Bed micro-concentration (for 1min) and automated AMDIS search within 12min. Using manual deconvolution by background subtraction of neighboring regions on the extracted ion chromatograms, the above-mentioned CWAs could be confirmed at lower concentration levels. The memory effects were also examined and we found that blister agents showed significantly more carry-over than nerve agents. Gasoline vapor was found to interfere with the detection of GB and GD, raising the concentration limits for confirmation in the presence of gasoline by both AMDIS search and manual deconvolution; however, GA and GF were not subject to interference by gasoline. Lewisite 1, and o-chlorobenzylidene malononitrile could also be confirmed by gas chromatography, but it was hard to quantify them. Vapors of phosgene, chlorine, and cyanogen chloride could be confirmed by direct mass spectrometric detection at concentration levels higher than 2, 140, and 10mg/m(3) respectively, by bypassing the micro-concentration trap and gas chromatographic separation. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Capillary reference half-cell

    DOEpatents

    Hall, Stephen H.

    1996-01-01

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods.

  6. Capillary reference half-cell

    DOEpatents

    Hall, S.H.

    1996-02-13

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods. 11 figs.

  7. Hybrid integrated PDMS microfluidics with a silica capillary.

    PubMed

    Dimov, Ivan K; Riaz, Asif; Ducrée, Jens; Lee, Luke P

    2010-06-07

    To harness the properties of both PDMS and silica, we have demonstrated hybrid integrated PDMS microfluidic systems with fused silica capillaries. The hybrid integrated PDMS microfluidics and silica capillary (iPSC) modules exhibit a novel architecture and method for leakage free CE sample injection merely requiring a single high voltage source and one pair of electrodes. The use of the iPSC device is based on a modular approach which allows the capillary to be reused extensively whilst replacing the attached fluidic module for different experiments. Integrating fused silica capillaries with PDMS microfluidic modules allows the direct application of a wide variety of well established conventional CE protocols for separations of complex analytes. Furthermore it bears the potential for facile coupling to standard electro-spray ionization mass spectrometry (ESI-MS), letting users focus on the sample analysis rather than the development of new separation protocols. The fabrication of the iPSC module consists of a simple and quick three-step method that submerges a fused silica capillary in PDMS prepolymer. After cross linking the prepolymer and punching the inlets, the iPSC module layer can be mounted onto a microfluidic device for CE separation.

  8. Capillary rogue waves.

    PubMed

    Shats, M; Punzmann, H; Xia, H

    2010-03-12

    We report the first observation of extreme wave events (rogue waves) in parametrically driven capillary waves. Rogue waves are observed above a certain threshold in forcing. Above this threshold, frequency spectra broaden and develop exponential tails. For the first time we present evidence of strong four-wave coupling in nonlinear waves (high tricoherence), which points to modulation instability as the main mechanism in rogue waves. The generation of rogue waves is identified as the onset of a distinct tail in the probability density function of the wave heights. Their probability is higher than expected from the measured wave background.

  9. Stability of capillary surfaces

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark

    1991-01-01

    An extensive data set quantifying the stability limits of capillary surfaces for a wide range of fluid properties, container geometry, and input disturbance and orientation does not currently exist. To begin to provide such a data set an experimental apparatus has been designed for which the dynamics and stability of fluid interfaces will be investigated. The apparatus consists primarily of a programmable shaker table and a high speed motion picture and video camera for viewing the fluid surface as drop tower tests will be performed to note the stability of a variety of surface/vessel configurations.

  10. Capillary suspensions: Particle networks formed through the capillary force

    PubMed Central

    Koos, Erin

    2014-01-01

    The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review. PMID:25729316

  11. Tapered capillary optics

    DOEpatents

    Hirsch, Gregory

    1998-01-01

    A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

  12. Capillary electrochromatography of cannabinoids.

    PubMed

    Lurie, I S; Meyers, R P; Conver, T S

    1998-08-01

    The applicability of capillary electrochromatography (CEC) with photodiode array UV detection for the analysis of cannabinoids is presented. Baseline separation of seven cannabinoids (cannabigerol, cannabidiol, cannabinol, delta-9-tetrahydrocannabinol, delta-8-tetrahydrocannabinol, cannabichromene, delta-9-tetrahydrocannabinolic acid) is obtained using a 3-micron CEC Hypersil C18 capillary with an acetonitrile/phosphate (pH 2.57) mobile phase. The effects of acetonitrile concentration, buffer concentration, voltage, temperature, stationary phase, and column length on the separation of the cannabinoids were investigated. Good short- and long-term precision in retention times are observed, with significant improvement obtained using relative retention times with cannabinol as reference compound. Although short- and long-term peak area precisions are poor, satisfactory reproducibility is obtained using relative peak areas with cannabinol as reference compound. The applicability of the CEC methodology to drug seizures was demonstrated on marijuana and hashish. Using a high-sensitivity UV flow cell with an extended path length of 1.2 mm, concentration sensitivities approaching HPLC were obtained.

  13. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

    A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

  14. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

    A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

  15. Noise suppressing capillary separation system

    DOEpatents

    Yeung, E.S.; Xue, Y.

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans. 13 figs.

  16. Capillary optics for radiation focusing

    SciTech Connect

    Peurrung, A.J.; Reeder, P.L.; Bliss, M.; Craig, R.A.; Lepel, E.A.; Stromswold, D.C.; Stoffels, J.; Sunberg, D.S.; Tenny, H.

    1996-11-01

    Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using {sup 58}Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics.

  17. Geometry-induced capillary emptying.

    PubMed

    Rascón, Carlos; Parry, Andrew O; Aarts, Dirk G A L

    2016-10-24

    When a capillary is half-filled with liquid and turned to the horizontal, the liquid may flow out of the capillary or remain in it. For lack of a better criterion, the standard assumption is that the liquid will remain in a capillary of narrow cross-section, and will flow out otherwise. Here, we present a precise mathematical criterion that determines which of the two outcomes occurs for capillaries of arbitrary cross-sectional shape, and show that the standard assumption fails for certain simple geometries, leading to very rich and counterintuitive behavior. This opens the possibility of creating very sensitive microfluidic devices that respond readily to small physical changes, for instance, by triggering the sudden displacement of fluid along a capillary without the need of any external pumping.

  18. 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.

  19. Geometry-induced capillary emptying

    PubMed Central

    Parry, Andrew O.; Aarts, Dirk G. A. L.

    2016-01-01

    When a capillary is half-filled with liquid and turned to the horizontal, the liquid may flow out of the capillary or remain in it. For lack of a better criterion, the standard assumption is that the liquid will remain in a capillary of narrow cross-section, and will flow out otherwise. Here, we present a precise mathematical criterion that determines which of the two outcomes occurs for capillaries of arbitrary cross-sectional shape, and show that the standard assumption fails for certain simple geometries, leading to very rich and counterintuitive behavior. This opens the possibility of creating very sensitive microfluidic devices that respond readily to small physical changes, for instance, by triggering the sudden displacement of fluid along a capillary without the need of any external pumping. PMID:27791079

  20. Enantiomer migration order in chiral capillary electrophoresis.

    PubMed

    Chankvetadze, Bezhan

    2002-11-01

    Enantiomer migration order (EMO) in chiral capillary electrophoresis (CE) represents a challenging issue, referred to in less than 20% of the articles on CE enantioseparations. This review article will (i) illustrate the actuality of the topic, (ii) discuss some technical problems related to EMO in CE enantioseparations, (iii) examine the principal differences between CE and other separation techniques from the viewpoint of enantiomer elution order, (iv) demonstrate the potential for a designed reversal of EMO in CE, and (v) emphasize the importance of studying EMO for better understanding of chiral CE as well as its more effective application. Along with CE, the results obtained by other instrumental techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), X-ray crystallography, as well as molecular modeling calculations will be shortly discussed. Rather than referring to all published examples of the opposite migration order of enantiomers in CE, the emphasis will be on general aspects. Recently, the reversal of the EMO was described in detail in a book chapter (Chankvetadze, B., Capillary Electrophoresis in Chiral Analysis, Wiley & Sons, Chichester, UK 1997, Chapter 12) as well as in three review articles.

  1. Physiological factors influencing capillary growth.

    PubMed

    Egginton, S

    2011-07-01

    (1) Angiogenesis (growth of new capillaries from an existing capillary bed) may result from a mismatch in microvascular supply and metabolic demand (metabolic error signal). Krogh examined the distribution and number of capillaries to explore the correlation between O(2) delivery and O(2) consumption. Subsequently, the heterogeneity in angiogenic response within a muscle has been shown to reflect either differences in fibre type composition or mechanical load. However, local control leads to targetted angiogenesis in the vicinity of glycolytic fibre types following muscle stimulation, or oxidative fibres following endurance training, while heterogeneity of capillary spacing is maintained during ontogenetic growth. (2) Despite limited microscopy resolution and lack of specific markers, Krogh's interest in the structure of the capillary wall paved the way for understanding the mechanisms of capillary growth. Angiogenesis may be influenced by the response of perivascular or stromal cells (fibroblasts, macrophages and pericytes) to altered activity, likely acting as a source for chemical signals modulating capillary growth such as vascular endothelial growth factor. In addition, haemodynamic factors such as shear stress and muscle stretch play a significant role in adaptive remodelling of the microcirculation. (3) Most indices of capillarity are highly dependent on fibre size, resulting in possible bias because of scaling. To examine the consequences of capillary distribution, it is therefore helpful to quantify the area of tissue supplied by individual capillaries. This allows the spatial limitations inherent in most models of tissue oxygenation to be overcome generating an alternative approach to Krogh's tissue cylinder, the capillary domain, to improve descriptions of intracellular oxygen diffusion. © 2010 The Author. Acta Physiologica © 2010 Scandinavian Physiological Society.

  2. Multidimensional capillary electrophoresis.

    PubMed

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

    2015-01-01

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

  3. Capillary electrophoresis of DNA.

    PubMed

    Smith, Alan; Nelson, Robert J

    2003-08-01

    Capillary electrophoresis (CE) is an alternative to conventional slab gel electrophoresis for the separation of DNA fragments. CE offers a number of advantages over slab gel separations in terms of speed, resolution, sensitivity, and data handling. Separation times are generally only a few minutes and the DNA is detected either by UV absorption or by fluorescent labeling. The quantity of DNA required for separation is in the nanogram range. Single-base resolution can be obtained on fragments up to several hundred base pairs. In the presence of appropriate standards, fragments can be accurately sized based on relative electrophoretic mobility. A protocol for the analysis of synthetic oligonucleotides in a flowable matrix is described in this unit.

  4. A capillary Archimedes' screw

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Dorbolo, Stephane

    2014-11-01

    As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a drop pending on a rotating spiral which is tilted toward the horizontal. The ascent of the drop to the top of the spiral is considered and a theoretical model based on geometrical considerations is proposed. The climb of the drop is limited by the fluid deposition on the screw at high capillary number and by a centrifugation phenomenon. We find out the range of fluid proprities and spiral characteristics for which an ascending motion of the drop is possible. Finally we discuss the efficiency of such system to extract a fluid from a bath at a centrimetric scale.

  5. Steady Capillary Driven Flow

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M.

    1996-01-01

    A steady capillary driven flow is developed for a liquid index in a circular tube which is partially coated with a surface modifier to produce a discontinuous wetting condition from one side of the tube to the other. The bulk flow is novel in that it is truly steady, and controlled solely by the physics associated with dynamic wetting. The influence of gravity on the flow is minimized through the use of small diameter tubes approximately O(1 mm) tested horizontally in a laboratory and larger tubes approximately O(10 mm) tested in the low gravity environment of a drop tower. Average steady velocities are predicted and compared against a large experimental data set which includes the effects of tube dimensions and fluid properties. The sensitivity of the velocity to surface cleanliness is dramatic and the advantages of experimentation in a microgravity environment are discussed.

  6. 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.

  7. 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.

  8. Inertial Rise in Short Capillaries

    NASA Astrophysics Data System (ADS)

    Shardt, Orest; Waghmare, Prashant; Mitra, Sushanta; Derksen, Jos

    2013-11-01

    We investigate the primarily inertial rise of liquid in vertical glass capillaries that are shorter than the equilibrium rise height (Jurin height). We focus on the behavior of the liquid upon reaching the top of the capillary and use high-speed imaging to observe the motion of the liquid-air interface with high spatial and temporal resolution. We examine the dependence of the interface behavior on the meniscus speed and capillary height and describe a new phenomenon. Upon reaching the upper edge of a sufficiently short capillary, the meniscus inverts, rises upward, and bulges out radially. The bulging liquid then wets the external surface of the capillary and slides down. The meniscus inside the capillary retracts, falling below the upper edge, and then oscillates vertically with decaying amplitude, inverting several times before reaching a steady shape. A theoretical analysis is used to interpret the conditions required for this phenomenon to occur. A key assumption in the analysis is that the transient flow is inertial and therefore the capillary driving force is balanced by the weight and inertia of the rising liquid column while viscous forces are comparatively small. The analysis points to the possibility of obtaining previously-unseen behavior under reduced gravity.

  9. Instability of the capillary bridge

    NASA Astrophysics Data System (ADS)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  10. 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.

  11. Capillary oscillations on liquid jets

    NASA Astrophysics Data System (ADS)

    Wetsel, Grover C.

    1980-07-01

    Capillary oscillations on modulated liquid jets have been investigated using laser illumination and electronic detection of the magnified jet shadow. The amplitudes of several wave harmonics of a growing spatial instability were measured as a function of distance from the orifice for a range of jet velocities and initial-disturbance amplitudes. The experimentally determined growth rates at the fundamental frequency are compared with theories of capillary-wave propagation. An empirically derived explanation of the suppression of satellite formation is given. Experimental evidence for infinite-wavelength capillary oscillations is reported; a description of these oscillations in terms of the Rayleigh theory is presented.

  12. Electrospraying from nanofluidic capillary slot

    NASA Astrophysics Data System (ADS)

    Arscott, Steve; Troadec, David

    2005-09-01

    We present here an original electrospray emitter tip based on a nanofluidic capillary slot. The nanofabrication involves focused ion beam etching to form the slot which has a cross-section of 50×300nm and a length of 4μm. The liquid is deformed into the nanofluidic capillary slot by capillary action; the electrospray is produced by the application of a low voltage. Using a water-methanol-formic acid solution, we have observed an electrospray onset voltage of 125V. At a measured electrospray current of 1nA, the unforced flow-rate is estimated to be 110pLmin-1.

  13. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  14. Mass spectrometry.

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  15. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    NASA Astrophysics Data System (ADS)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  16. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  17. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, B.D.; Fought, E.R.

    1987-11-10

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface. 8 figs.

  18. Capillary Fracturing in Granular Media

    NASA Astrophysics Data System (ADS)

    Holtzman, Ran; Szulczewski, Michael L.; Juanes, Ruben

    2012-06-01

    We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and “capillary fracturing,” where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

  19. Capillary fracturing in granular media.

    PubMed

    Holtzman, Ran; Szulczewski, Michael L; Juanes, Ruben

    2012-06-29

    We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing," where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

  20. Surface Tension and Capillary Rise

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1972-01-01

    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  1. 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.

  2. Capillary gas-solid chromatography

    NASA Astrophysics Data System (ADS)

    Berezkin, Viktor G.

    1996-11-01

    The current state of gas adsorption chromatography on open tubular capillary columns is analysed. The history of the development of this method and its role in gas chromatography are considered. The preparation of open tubular adsorption capillary columns, fundamentals of the theory of retention and of broadening of chromatographic zones, and the use of columns of this type in practical analytical chemistry are discussed. The bibliography includes 148 references.

  3. Capillary viscosimetry on ferrofluids.

    PubMed

    Pop, L M; Odenbach, S

    2008-05-21

    Experiments performed for different ferrofluids under shear flow have shown that an increase of the magnetic field strength applied to the sample yields an increase of the fluid's viscosity, the so called magnetoviscous effect. It has been shown that the magnitude of the effect is strongly related to the modification of the microstructure of ferrofluids and can be influenced by varying both the dipole-dipole interaction between the particles and the concentration of large particles within the fluid. This result has been further used to synthesize new ferrofluids which, on one hand, are more compatible for technical applications but, on the other hand, led to difficulties for the experimenters in measuring the viscous behavior in the presence of a magnetic field. To overcome this problem, a specially designed ferrofluid-compatible capillary viscometer has been developed. Within this paper, the experimental setup as well as experimental results concerning the investigation of the magnetoviscous effect in both diluted and concentrated cobalt-based ferrofluids are presented.

  4. Sheathless capillary electrophoresis‐mass spectrometry for anionic metabolic profiling

    PubMed Central

    Gulersonmez, Mehmet Can; Lock, Stephen; Hankemeier, Thomas

    2015-01-01

    The performance of CE coupled on‐line to MS via a sheathless porous tip sprayer was evaluated for anionic metabolic profiling. A representative metabolite mixture and biological samples were used for the evaluation of various analytical parameters, such as peak efficiency (plate numbers), migration time and peak area repeatability, and LODs. The BGE, i.e. 10% acetic acid (pH 2.2), previously used for cationic metabolic profiling was now assessed for anionic metabolic profiling by using MS detection in negative ion mode. For test compounds, RSDs for migration times and peak areas were below 2 and 11%, respectively, and plate numbers ranged from 60 000 to 40 0000 demonstrating a high separation efficiency. Critical metabolites with low or no retention on reversed‐phase LC could be efficiently separated and selectively analyzed by the sheathless CE‐MS method. An injection volume of only circa 20 nL resulted in LODs between 10 and 200 nM (corresponding to an amount of 0.4–4 fmol), which was an at least tenfold improvement as compared to LODs obtained by conventional CE‐MS approaches for these analytes. The methodology was applied to anionic metabolic profiling of glioblastoma cell line extracts. Overall, a sheathless CE‐MS method has been developed for highly efficient and sensitive anionic metabolic profiling studies, which can also be used for cationic metabolic profiling studies by only switching the MS detection and separation voltage polarity. PMID:26593113

  5. Sheathless capillary electrophoresis-mass spectrometry for anionic metabolic profiling.

    PubMed

    Gulersonmez, Mehmet Can; Lock, Stephen; Hankemeier, Thomas; Ramautar, Rawi

    2016-04-01

    The performance of CE coupled on-line to MS via a sheathless porous tip sprayer was evaluated for anionic metabolic profiling. A representative metabolite mixture and biological samples were used for the evaluation of various analytical parameters, such as peak efficiency (plate numbers), migration time and peak area repeatability, and LODs. The BGE, i.e. 10% acetic acid (pH 2.2), previously used for cationic metabolic profiling was now assessed for anionic metabolic profiling by using MS detection in negative ion mode. For test compounds, RSDs for migration times and peak areas were below 2 and 11%, respectively, and plate numbers ranged from 60 000 to 40 0000 demonstrating a high separation efficiency. Critical metabolites with low or no retention on reversed-phase LC could be efficiently separated and selectively analyzed by the sheathless CE-MS method. An injection volume of only circa 20 nL resulted in LODs between 10 and 200 nM (corresponding to an amount of 0.4-4 fmol), which was an at least tenfold improvement as compared to LODs obtained by conventional CE-MS approaches for these analytes. The methodology was applied to anionic metabolic profiling of glioblastoma cell line extracts. Overall, a sheathless CE-MS method has been developed for highly efficient and sensitive anionic metabolic profiling studies, which can also be used for cationic metabolic profiling studies by only switching the MS detection and separation voltage polarity. © 2015 The Authors ELECTROPHORESIS Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  6. Characterization of a liposome-based formulation of oxaliplatin using capillary electrophoresis: encapsulation and leakage.

    PubMed

    Franzen, Ulrik; Nguyen, Tam T T N; Vermehren, Charlotte; Gammelgaard, Bente; Ostergaard, Jesper

    2011-04-28

    A capillary electrophoresis-based method to characterize a PEGylated liposomal drug formulation of the anti-cancer agent oxaliplatin was developed. Pharmaceutical characterization in terms of determination of the free and total oxaliplatin concentrations in the liposomal formulation was successfully performed allowing calculation of the percentage of encapsulated drug and encapsulation efficiency. The trapping efficiency was likewise calculated. The capillary electrophoresis method allowed liposome characterization in the intended formulation media (sucrose solution with low electrolyte concentration), and the attained results were consistent with inductively coupled plasma mass spectrometry measurements. Accelerated drug leakage studies were initiated by the sonication of the PEGylated formulation, using an ultrasound probe, subsequently the drug leakage was determined by capillary electrophoresis. The results obtained with the PEGylated liposomes demonstrate that capillary electrophoresis may be a useful tool for the characterization of liposomal drug formulations. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Capillary electrophoresis in pharmaceutical analysis: a survey on recent applications.

    PubMed

    Suntornsuk, Leena

    2007-10-01

    Capillary electrophoresis (CE) has a significant role in drug discovery and manufacturing processes and has a potential to grow further, due to new developments that can provide highly sensitive and high throughput analysis. This review illustrates recent applications of CE in pharmaceutical analysis (2005-present). The history, principles, instruments, and conventional modes of CE are briefly described. Applications for drug analysis by various techniques of CE are presented in six tables: capillary zone electrophoresis (CZE) (Table I), micellar electrokinetic chromatography (MEKC) and microemulsion electrokinetic chromatography (MEEKC) (Table II), non-aqueous CE (NACE) (Table III), chiral CE (Table IV), CE-mass spectrometry (MS) microchip CE (Table V), and multiplexed CE (MCE) (Table VI).

  8. Threshold capillary pressure in capillaries with curved sides

    NASA Astrophysics Data System (ADS)

    Lago, Marcelo; Araujo, Mariela

    2003-03-01

    Modeling of fluid flow through permeable media is of great importance in assessing the performance of both hydrocarbon reservoirs and aquifers. In this process, network models based on cylindrical capillaries with circular cross sections are frequently used. This type of capillaries are not able to reproduce interesting physical phenomena observed in the experiments, for example, situations where there is flow by films with the wetting fluid occupying the crevices and wedges of the structure. We present an analysis of the behavior of the capillary pressure of a droplet of non-wetting fluid with an infinite length, inside objects of cylindrical symmetry with curved sides. The calculation is based on a method proposed by Mayer and Stowe and Princen (MS-P). Different capillary geometries are considered, and the behavior of the capillary pressure and transversal fluid saturation as a function of the shape factor is studied. The results found either analytically or numerically, allow to understand the relation between geometry and flow properties, and helps in the building of more realistic pore network models for flow studies at the pore scale.

  9. Pulsatility of Parafoveal Capillary Leukocytes

    PubMed Central

    Martin, Joy A.; Roorda, Austin

    2009-01-01

    The use of adaptive optics (AO) in a confocal scanning laser ophthalmoscope (AOSLO) allows for long-term imaging of parafoveal capillary leukocyte movement and measurement of leukocyte velocity without contrast dyes. We applied the AOSLO to investigate the possible role of the cardiac cycle on capillary leukocyte velocity by directly measuring capillary leukocyte pulsatility. The parafoveal regions of 8 eight normal healthy subjects with clear ocular media were imaged with an AOSLO. All subjects were dilated and cyclopleged. The AOSLO field of view was either 1.4 × 1.5 degrees or 2.35 × 2.5 degrees, the imaging wavelength was 532 nm and the frame rate was 30 fps. A photoplethysmograph was used to record the subject’s pulse synchronously with each AOSLO video. Parafoveal capillary leukocyte velocities and pulsatility were determined for two or three capillaries per subject. Leukocyte velocity and pulsatility were determined for all eight subjects. The mean parafoveal capillary leukocyte velocity for all subjects was Vmean = 1.30 mm/sec (SD = +/− 0.40 mm/sec). There was a statistically significant difference between leukocyte velocities, Vmax and Vmin, over the pulse cycle for each subject (p<0.05). The mean pulsatility was Pmean= 0.45 (+/− 0.09). Parafoveal capillary leukocyte pulsatility can be directly and non-invasively measured without the use of contrast dyes using an AOSLO. A substantial amount of the variation found in leukocyte velocity is due to the pulsatility that is induced by the cardiac cycle. By controlling for the variation in leukocyte velocity caused by the cardiac cycle, we can better detect other changes in retinal leukocyte velocity induced by disease or pharmaceutical agents. PMID:18708051

  10. Potential of polyE-323 coated capillaries for capillary electrophoresis of lipids.

    PubMed

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

    2013-11-22

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

  11. Combination of capillary isoelectric focusing in a tapered capillary with MALDI-TOF MS for rapid and reliable identification of Dickeya species from plant samples.

    PubMed

    Horká, Marie; Salplachta, Jiří; Karásek, Pavel; Kubesová, Anna; Horký, Jaroslav; Matoušková, Hana; Slais, Karel; Roth, Michal

    2013-07-16

    This study was undertaken to investigate feasibility of a combination of capillary isoelectric focusing (CIEF) in a tapered fused silica (FS) capillary with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for a rapid and reliable identification of bacteria taken from plant-tissue-containing samples. Eight strains representing different species of the genus Dickeya were selected on the basis of close proximity of their isoelectric points: D. chrysanthemi, D. chrysanthemi bv. parthenii, D. chrysanthemi bv. chrysanthemi, D. dadantii, D. paradisiaca, D. solani, D. diffenbachiae, and D. dianthicola. Because the Dickeya species (spp.) cannot be easily discriminated from each other when CIEF is performed in a cylindrical FS capillary (commonly used in CIEF) even if a narrow pH gradient is used, a tapered FS capillary was employed instead, which enabled satisfactory discrimination of the examined bacteria due to enhanced separation efficiency of CIEF in the tapered FS capillary. CIEF in the tapered FS capillary was also successfully used for the detection and characterization of Dickeya spp. in a plant-tissue-containing sample. Then an off-line combination of CIEF with MALDI-TOF MS was employed for rapid and reliable identification of Dickeya spp. in the plant-tissue-containing sample. It was found that the presence of plant tissue did not affect the results, making the proposed procedure very promising with respect to the fast and reliable detection and identification of bacteria in plant-tissue-containing samples.

  12. Capillary wave measurements on helically-supported capillary channels

    NASA Astrophysics Data System (ADS)

    Chandurwala, Fahim; Thiessen, David

    2010-10-01

    NASA is considering power generation by the Rankine cycle to save weight on long-duration manned missions to the moon or Mars. Phase separation technology is critical to this process in microgravity. Arrays of capillary channels might be useful for filtering liquid drops from a flowing vapor. The efficiency of droplet capture by a helically-supported capillary channel is being studied. A droplet impinging on the channel launches capillary waves that propagate down the channel helping to dissipate some of the drop's kinetic energy. High-speed video of the channel combined with image processing allows for measurement of the amplitude and speed of the wave packets. Increasing the pitch of the support structure decreases the wave speed. An understanding of the dynamic response of the channel to drop impact is a first step in predicting drop-capture efficiency.

  13. Raman Spectrometry.

    ERIC Educational Resources Information Center

    Gardiner, Derek J.

    1980-01-01

    Reviews mainly quantitative analytical applications in the field of Raman spectrometry. Includes references to other reviews, new and analytically untested techniques, and novel sampling and instrument designs. Cites 184 references. (CS)

  14. Raman Spectrometry.

    ERIC Educational Resources Information Center

    Gardiner, Derek J.

    1980-01-01

    Reviews mainly quantitative analytical applications in the field of Raman spectrometry. Includes references to other reviews, new and analytically untested techniques, and novel sampling and instrument designs. Cites 184 references. (CS)

  15. Capillary imbibition in parallel tubes

    NASA Astrophysics Data System (ADS)

    McRae, Oliver; Ramakrishnan, T. S.; Bird, James

    2016-11-01

    In modeling porous media two distinct approaches can be employed; the sample can be examined holistically, using global variables such as porosity, or it can be treated as a network of capillaries connected in series to various intermediate reservoirs. In forced imbibition this series-based description is sufficient to characterize the flow, due to the presence of an externally maintained pressure difference. However, in spontaneous imbibition, flow is driven by an internal capillary pressure, making it unclear whether a series-based model is appropriate. In this talk, we show using numerical simulations the dynamics of spontaneous imbibition in concentrically arranged capillary tubes. This geometry allows both tubes access to a semi-infinite reservoir but with inlets in close enough proximity to allow for interference. We compare and contrast the results of our simulations with theory and previous experiments. Schlumberger-Doll Research.

  16. Decay of capillary wave turbulence.

    PubMed

    Deike, Luc; Berhanu, Michael; Falcon, Eric

    2012-06-01

    We report on the observation of freely decaying capillary wave turbulence on the surface of a fluid. The capillary wave turbulence spectrum decay is found to be self-similar in time with the same power law exponent as the one found in the stationary regime, in agreement with weak turbulence predictions. The amplitude of all Fourier modes are found to decrease exponentially with time at the same damping rate. The longest wavelengths involved in the system are shown to be damped by a viscous surface boundary layer. These long waves play the role of an energy source during the decay that sustains nonlinear interactions to keep capillary waves in a wave turbulent state.

  17. Paramecium swimming in capillary tube

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

    2012-04-01

    Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

  18. Optothermally actuated capillary burst valve

    NASA Astrophysics Data System (ADS)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

    2017-04-01

    We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

  19. Energy Invariance in Capillary Systems.

    PubMed

    Ruiz-Gutiérrez, Élfego; Guan, Jian H; Xu, Ben; McHale, Glen; Wells, Gary G; Ledesma-Aguilar, Rodrigo

    2017-05-26

    We demonstrate the continuous translational invariance of the energy of a capillary surface in contact with reconfigurable solid boundaries. We present a theoretical approach to find the energy-invariant equilibria of spherical capillary surfaces in contact with solid boundaries of arbitrary shape and examine the implications of dynamic frictional forces upon a reconfiguration of the boundaries. Experimentally, we realize our ideas by manipulating the position of a droplet in a wedge geometry using lubricant-impregnated solid surfaces, which eliminate the contact-angle hysteresis and provide a test bed for quantifying dissipative losses out of equilibrium. Our experiments show that dissipative energy losses for an otherwise energy-invariant reconfiguration are relatively small, provided that the actuation time scale is longer than the typical relaxation time scale of the capillary surface. We discuss the wider applicability of our ideas as a pathway for liquid manipulation at no potential energy cost in low-pinning, low-friction situations.

  20. Energy Invariance in Capillary Systems

    NASA Astrophysics Data System (ADS)

    Ruiz-Gutiérrez, Élfego; Guan, Jian H.; Xu, Ben; McHale, Glen; Wells, Gary G.; Ledesma-Aguilar, Rodrigo

    2017-05-01

    We demonstrate the continuous translational invariance of the energy of a capillary surface in contact with reconfigurable solid boundaries. We present a theoretical approach to find the energy-invariant equilibria of spherical capillary surfaces in contact with solid boundaries of arbitrary shape and examine the implications of dynamic frictional forces upon a reconfiguration of the boundaries. Experimentally, we realize our ideas by manipulating the position of a droplet in a wedge geometry using lubricant-impregnated solid surfaces, which eliminate the contact-angle hysteresis and provide a test bed for quantifying dissipative losses out of equilibrium. Our experiments show that dissipative energy losses for an otherwise energy-invariant reconfiguration are relatively small, provided that the actuation time scale is longer than the typical relaxation time scale of the capillary surface. We discuss the wider applicability of our ideas as a pathway for liquid manipulation at no potential energy cost in low-pinning, low-friction situations.

  1. Electrical resistance of a capillary endothelium

    PubMed Central

    1981-01-01

    The electrical resistance of consecutive segments of capillaries has been determined by a method in which the microvessels were treated as a leaky, infinite cable. A two-dimensional analytical model to describe the potential field in response to intracapillary current injection was formulated. The model allowed determination of the electrical resistance from four sets of data: the capillary radius, the capillary length constant, the length constant in the mesentery perpendicular to the capillary, and the relative potential drop across the capillary wall. Of particular importance were the mesothelial membranes covering the mesenteric capillaries with resistances several times higher than that of the capillary endothelium. 27 frog mesenteric capillaries were characterized. The average resistance of the endothelium was 1.85 omega cm2, which compares well with earlier determinations of the ionic permeability of such capillaries. However, heterogeneity with respect to resistance was observed, that of 10 arterial capillaries being 3.0 omega cm2 as compared with 0.95 omega cm2 for 17 mid- and venous capillaries. The average in situ length constant was 99 micrometers for the arterial capillaries and 57 micrometers for the mid- and venous capillaries. It is likely that the ions that carry the current must move paracellularly, through junctions that are leaky to small solutes. PMID:7241087

  2. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  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. Capillary interactions in Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Guzowski, J.; Tasinkevych, M.; Dietrich, S.

    2011-09-01

    The effective capillary interaction potentials for small colloidal particles trapped at the surface of liquid droplets are calculated analytically. Pair potentials between capillary monopoles and dipoles, corresponding to particles floating on a droplet with a fixed center of mass and subjected to external forces and torques, respectively, exhibit a repulsion at large angular separations and an attraction at smaller separations, with the latter resembling the typical behavior for flat interfaces. This change of character is not observed for quadrupoles, corresponding to free particles on a mechanically isolated droplet. The analytical results are compared with the numerical minimization of the surface free energy of the droplet in the presence of spherical or ellipsoidal particles.

  5. Nonsteady Flow in Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Hara, Ayako

    2000-03-01

    Surface phenomena in the field of electron devices and the problem of how long. It takes plants to absorb water during their growth in hydroponic cultivation is attraching the attention of riseachers. However, the related study of non-steady flow in capillary tubes has a number of issues that require investigation. In response to this situation, we made attempted to assess nonsteady fiow in capillary tubes, the liquid rise time and other issues, using a motion equation that takes factors including the friction force of the tube and the surface tension into consideration.

  6. Capillary haemangioma of the testis

    PubMed Central

    Mazal, P; Kratzik, C; Kain, R; Susani, M

    2000-01-01

    A case of testicular capillary haemangioma is reported and the importance of intraoperative examination of this very rare lesion emphasised. Capillary haemangioma of the testis can be similar to malignant testicular tumours on clinical presentation, as well as on ultrasonography and magnetic resonance imaging, and therefore should be included in the intraoperative differential diagnosis. Because of the benign nature of this lesion, conservative surgical treatment by means of tumour enucleation with preservation of the testis is possible, if intraoperative examination of frozen sections of representative tissue can be performed. Key Words: testis • haemangioma PMID:11002773

  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. 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.

  9. 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.

  10. 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.

  11. Particle trajectories in linear periodic capillary and capillary-gravity water waves.

    PubMed

    Henry, David

    2007-09-15

    Surface tension plays a significant role as a restoration force in the setting of small-amplitude waves, leading to pure capillary and gravity-capillary waves. We show that within the framework of linear theory, the particle paths in a periodic gravity-capillary or pure capillary wave propagating at the surface of water over a flat bed are not closed.

  12. Bacterial motion in narrow capillaries

    PubMed Central

    Ping, Liyan; Wasnik, Vaibhav; Emberly, Eldon

    2014-01-01

    Motile bacteria often have to pass through small tortuous pores in soil or tissue of higher organisms. However, their motion in this prevalent type of niche is not fully understood. Here, we modeled it with narrow glass capillaries and identified a critical radius (Rc) for bacterial motion. Near the surface of capillaries narrower than that, the swimming trajectories are helices. In larger capillaries, they swim in distorted circles. Under non-slip condition, the peritrichous Escherichia coli swam in left-handed helices with an Rc of ∼10 μm near glass surface. However, slipping could occur in the fast monotrichous Pseudomonas fluorescens, when a speed threshold was exceeded, and thus both left-handed and right-handed helices were executed in glass capillaries. In the natural non-cylindrical pores, the near-surface trajectories would be spirals and twisted loops. Engaging in such motions reduces the bacterial migration rate. With a given pore size, the run length and the tumbling angle of the bacterium determine the probability and duration of their near-surface motion. Shear flow and chemotaxis potentially enhance it. Based on this observation, the puzzling previous observations on bacterial migration in porous environments can be interpreted. PMID:25764548

  13. Capillary waves and ellipsometry experiments

    NASA Astrophysics Data System (ADS)

    Bonn, D.; Wegdam, G. H.

    1992-09-01

    The inclusion of higher-order terms in the capillary-wave Hamiltonian may reduce the contributions of these fluctuations to the ellipsometric coefficients. We show that the renormalization of capillary waves at a fluid-fluid interface by Sengers and van Leeuwen [Phys. Rev. A 39 (1989) 6346] using the wave vector-dependent surface tension that follows from the coupled mode theory by Meunier [Phys. France 48 (1987)1819] yields a satisfactory agreement with recent ellipsometry measurements by Schmidt [Phys. Rev. A 38 (1988) 567]. The interface is viewed upon as an intrinsic interface broadened by capillary waves. We suppose that the cutoff wave vector q_{max} that follows from mode-coupling theory marks the transition from the short-wavelength bulk-like fluctuations that contribute to the bare surface tension to the long-wavelength capillary wave-like fluctuations that contribute to the full surface tension. This enables us to calculate, without any adjustable parameters, both the ratio of the bare and experimental surface tension and the universal constant for the elliptical thickness of the interface. Both agree remarkably well with experimental values.

  14. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  15. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  16. 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.

  17. Tapered splice technique for capillary optical fiber

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoliang; Xiang, Huoxing

    2017-07-01

    We propose a simple but effective technique. It is concerned with a tapered splice technique for capillary optical fiber. In order to contrast, we investigate two kinds of capillary optical fiber. One of the capillary optical fiber has the annular core around the air hole and the other one has the embedded annular core around the inner cladding. We demonstrate the tapered splice technique works for both of the capillary optical fiber in experiment. It is the key to improve the coupling efficiency of the capillary optical fiber. We also build a theoretical model to predict the optical power of the capillary optical fiber and it is confirmed by the experimental results. The method provides an insight of the mode conversion characteristics of capillary optical fiber. It should be used as an easy way to realize the fiber-based in-line components and should be more importantly to explore new possibilities with this kind of fiber.

  18. Emission Spectrometry.

    ERIC Educational Resources Information Center

    Keliher, Peter N.; And Others

    1984-01-01

    Presented is a review of selected literature on emission spectrometry published during 1982 and 1983. The review is organized under these headings: books and reviews; spectral descriptions and classifications; instrumentation; standards, samples, nomenclature, calibration, calculations; excitation sources; selected applications; and meetings. (JN)

  19. Current medical research with the application of coupled techniques with mass spectrometry

    PubMed Central

    Kałużna-Czaplińska, Joanna

    2011-01-01

    Summary The most effective methods of analysis of organic compounds in biological fluids are coupled chromatographic techniques. Capillary gas chromatography/mass spectrometry (GC-MS) allows the most efficient separation, identification and quantification of volatile metabolites in biological fluids. Liquid chromatography-mass spectrometry (LC-MS) is especially suitable for the analysis of non-volatile and/or thermally unstable compounds. A major drawback of liquid chromatography-mass spectrometry is that no standard spectral libraries such as NIST and Wiley for GC-MS are available to facilitate the identification of unknown compounds. Moreover, the identification of potential new compounds, especially new biomarkers in LC-MS, is much more challenging than in GC-MS. Capillary electrophoresis coupled with mass spectrometry (CE-MS) has been widely used to characterize metabolomes. Capillary electrophoresis is a powerful technique for the separation of charged metabolites, offering high analyte resolution. The advantages of CE-MS are applicability for hydrophilic metabolites, robust separation efficiency and short duration of analysis. This review provides an overview of current chromatographic methods – gas chromatography – mass spectrometry, liquid chromatography – mass spectrometry and capillary electrophoresis-mass spectrometry – and their applications in current medical research. The focus is on the description of metabonomics research, strategies for biomarkers identification, medical diagnoses of diseases and research of drugs. PMID:21525822

  20. Capillary rise in cellulose sponges

    NASA Astrophysics Data System (ADS)

    Kim, Jungchul; Kim, Ho-Young; Mahadevan, L.

    2011-11-01

    A cellulose sponge, commonly used for clean-up jobs, can absorb and hold a significant amount of water within its pores, whose size ranges from micrometers to millimeters. We investigate the dynamics of capillary rise of water in the sponge using a combination of experiment and theory. We find that the rate of the capillary rise is significantly lower than Washburn's rule that assumes the sponge as a row of adjoined pores and the liquid flow to be driven by the Laplace pressure. We introduce a novel theory to model the flow in the hygroscopic porous media by combining Darcy's law based on the moisture concentration and the modified Young-Laplace equation. The scaling law constructed through this work agrees well with the experimental results.

  1. Step-gradient capillary electrochromatography.

    PubMed

    Euerby, M R; Gilligan, D; Johnson, C M; Bartle, K D

    1997-10-01

    The analytical benefits of using a step-gradient in capillary electrochromatography (CEC) are demonstrated. The application of step-gradient CEC to the analysis of six diuretics of widely differing lipophilicities was evaluated and shown to result in a marked reduction in the analysis time and an improvement in the peak shape for later-eluting lipophilic components. When the step-gradient approach was performed in an automated mode, the retention time RSD for repeated injections was below 1%.

  2. Capillary electrophoresis systems and methods

    DOEpatents

    Dorairaj, Rathissh [Hillsboro, OR; Keynton, Robert S [Louisville, KY; Roussel, Thomas J [Louisville, KY; Crain, Mark M [Georgetown, IN; Jackson, Douglas J [New Albany, IN; Walsh, Kevin M [Louisville, KY; Naber, John F [Goshen, KY; Baldwin, Richard P [Louisville, KY; Franco, Danielle B [Mount Washington, KY

    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.

  3. Capillary stretching of elastic fibers

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  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. Capillary-driven automatic packaging.

    PubMed

    Ding, Yuzhe; Hong, Lingfei; Nie, Baoqing; Lam, Kit S; Pan, Tingrui

    2011-04-21

    Packaging continues to be one of the most challenging steps in micro-nanofabrication, as many emerging techniques (e.g., soft lithography) are incompatible with the standard high-precision alignment and bonding equipment. In this paper, we present a simple-to-operate, easy-to-adapt packaging strategy, referred to as Capillary-driven Automatic Packaging (CAP), to achieve automatic packaging process, including the desired features of spontaneous alignment and bonding, wide applicability to various materials, potential scalability, and direct incorporation in the layout. Specifically, self-alignment and self-engagement of the CAP process induced by the interfacial capillary interactions between a liquid capillary bridge and the top and bottom substrates have been experimentally characterized and theoretically analyzed with scalable implications. High-precision alignment (of less than 10 µm) and outstanding bonding performance (up to 300 kPa) has been reliably obtained. In addition, a 3D microfluidic network, aligned and bonded by the CAP technique, has been devised to demonstrate the applicability of this facile yet robust packaging technique for emerging microfluidic and bioengineering applications.

  6. Evaluation of capillary chromatographic supports for immobilized human purine nucleoside phosphorylase in frontal affinity chromatography studies.

    PubMed

    de Moraes, Marcela Cristina; Temporini, Caterina; Calleri, Enrica; Bruni, Giovanna; Ducati, Rodrigo Gay; Santos, Diógenes Santiago; Cardoso, Carmen Lucia; Cass, Quezia Bezerra; Massolini, Gabriella

    2014-04-18

    The aim of this work was to optimize the preparation of a capillary human purine nucleoside phosphorylase (HsPNP) immobilized enzyme reactor (IMER) for characterization and affinity screening studies of new inhibitors by frontal affinity chromatography coupled to mass spectrometry (FAC-MS). For this purpose two monolithic supports, a Chromolith Speed Rod (0.1mm I.D.×5cm) and a methacrylate-based monolithic epoxy polymeric capillary column (0.25mm I.D.×5cm) with epoxy reactive groups were considered and compared to an IMER previously developed using an open fused silica capillary. Each HsPNP-IMER was characterized in terms of catalytic activity using Inosine as standard substrate. Furthermore, they were also explored for affinity ranking experiments. Kd determination was carried out with the based fused silica HsPNP-IMER and the results are herein discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Mass Spectrometry of Intact Membrane Protein Complexes

    PubMed Central

    Laganowsky, Arthur; Reading, Eamonn; Hopper, Jonathan T.S.; Robinson, Carol V.

    2014-01-01

    Mass spectrometry of intact soluble protein complexes has emerged as a powerful technique to study the stoichiometry, structure-function and dynamics of protein assemblies. Recent developments have extended this technique to the study of membrane protein complexes where it has already revealed subunit stoichiometries and specific phospholipid interactions. Here, we describe a protocol for mass spectrometry of membrane protein complexes. The protocol begins with preparation of the membrane protein complex enabling not only the direct assessment of stoichiometry, delipidation, and quality of the target complex, but also evaluation of the purification strategy. A detailed list of compatible non-ionic detergents is included, along with a protocol for screening detergents to find an optimal one for mass spectrometry, biochemical and structural studies. This protocol also covers the preparation of lipids for protein-lipid binding studies and includes detailed settings for a Q-ToF mass spectrometer after introduction of complexes from gold-coated nanoflow capillaries. PMID:23471109

  8. Fluid Delivery System For Capillary Electrophoretic Applications.

    DOEpatents

    Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

    2002-04-23

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  9. Progression of Diabetic Capillary Occlusion: A Model

    PubMed Central

    Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

    2016-01-01

    An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

  10. Quantifying the cleanliness of glass capillaries.

    PubMed

    Bowman, C L

    1998-01-01

    I used capillary rise methods to investigate the lumenal surface properties of quartz (fused silica, Amersil T-08), borosilicate (Corning 7800), and high-lead glass (Corning 0010) capillaries commonly used to make patch pipets. I calculated the capillary rise and contact angle for water and methanol from weight measurements. The capillary rise was compared with the theoretical maximum value calculated by assuming each fluid perfectly wetted the lumenal surface of the glass (i.e., zero contact angle, which reflects the absence of surface contamination). For borosilicate, high-lead, and quartz capillaries, the rise for water was substantially less than the theoretical maximum rise. Exposure of the borosilicate, lead, and quartz capillaries to several cleaning methods resulted in substantially better--but not perfect--agreement between the theoretical maximum rise and calculated capillary rise. By contrast, the capillary rise for methanol was almost identical in untreated and cleaned capillaries, but less than its theoretical maximum rise. The residual discrepancy between the observed and theoretical rise for water could not be improved on by trying a variety of cleaning procedures, but some cleaning methods were superior to others. The water solubility of the surface contaminants, deduced from the effectiveness of repeated rinsing, was different for each of the three types of capillaries examined: Corning 7800 > quartz > Corning 0010. A surface film was also detected in quatz tubing with an internal filament. I conclude that these borosilicate, quartz, and high-lead glass capillaries have a film on the lumenal surface, which can be removed using appropriate cleaning methods. The surface contaminants may be unique to each type of capillary and may also be hydrophobic. Two simple methods are presented to quantitate the cleanliness of glass capillary tubing commonly used to make pipets for studies of biological membranes. It is not known if the surface film is of

  11. Joule heating in packed capillaries used in capillary electrochromatography.

    PubMed

    Rathore, Anurag S; Reynolds, Kimberly J; Colón, Luis A

    2002-09-01

    Effective heat dissipation is critical for reproducible and efficient separations in electrically driven separation systems. Flow rate, retention kinetics, and analyte diffusion rates are some of the characteristics that are affected by variation in the temperature of the mobile phase inside the column. In this study, we examine the issue of Joule heating in packed capillary columns used in capillary electrochromatography (CEC). As almost all commonly used CEC packings are poor thermal conductors, it is assumed that the packing particles do not conduct heat and heat transfer is solely through the mobile phase flowing through the system. The electrical conductivity of various mobile phases was measured at different temperatures by a conductivity meter and the temperature coefficient for each mobile phase was calculated. This was followed by measurement of the electrical current at several applied voltages to calculate the conductivity of the solution within the column as a function of the applied voltage. An overall increase in the conductivity is attributed to Joule heating within the column, while a constant conductivity means good heat dissipation. A plot of conductivity versus applied voltage was used as the indicator of poor heat dissipation. Using theories that have been proposed earlier for modeling of Joule heating effects in capillary electrophoresis (CE), we estimated the temperature within CEC columns. Under mobile and stationary phase conditions typically used in CEC, heat dissipation was found to be not always efficient. Elevated temperatures within the columns in excess of 23 degrees C above ambient temperature were calculated for packed columns, and about 35 degrees C for an open column, under a given set of conditions. The results agree with recently published experimental findings with nuclear magnetic resonance (NMR) thermometry, and Raman spectroscopic measurements.

  12. Capillary pumped loop body heat exchanger

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

    1998-01-01

    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  13. Microfluidic PMMA interfaces for rectangular glass capillaries

    NASA Astrophysics Data System (ADS)

    Evander, Mikael; Tenje, Maria

    2014-02-01

    We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics.

  14. 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

  15. Equilibrium capillary forces with atomic force microscopy.

    PubMed

    Sprakel, J; Besseling, N A M; Leermakers, F A M; Cohen Stuart, M A

    2007-09-07

    We present measurements of equilibrium forces resulting from capillary condensation. The results give access to the ultralow interfacial tensions between the capillary bridge and the coexisting bulk phase. We demonstrate this with solutions of associative polymers and an aqueous mixture of gelatin and dextran, with interfacial tensions around 10 microN/m. The equilibrium nature of the capillary forces is attributed to the combination of a low interfacial tension and a microscopic confinement geometry, based on nucleation and growth arguments.

  16. Heuristic approach to capillary pressures averaging

    SciTech Connect

    Coca, B.P.

    1980-10-01

    Several methods are available to average capillary pressure curves. Among these are the J-curve and regression equations of the wetting-fluid saturation in porosity and permeability (capillary pressure held constant). While the regression equation seem completely empiric, the J-curve method seems to be theoretically sound due to its expression based on a relation between the average capillary radius and the permeability-porosity ratio. An analysis is given of each of these methods.

  17. Capillaroscopy and the measurement of capillary pressure

    PubMed Central

    Shore, Angela C

    2000-01-01

    Capillaries play a critical role in cardiovascular function as the point of exchange of nutrients and waste products between the tissues and circulation. Studies of capillary function in man are limited by access to the vascular bed. However, skin capillaries can readily be studied by the technique of capillaroscopy which enables the investigator to assess morphology, density and blood flow velocity. It is also possible to estimate capillary pressure by direct cannulation using glass micropipettes. This review will describe the techniques used to make these assessments and will outline some of the changes that are seen in health and disease. PMID:11136289

  18. Oxygen exchange in silicone rubber capillaries.

    PubMed

    Heineken, F G; Predecki, P K; Filley, G F

    1978-06-01

    Capillaries of 7 and 12.5 mu diameter have been fabricated in silicone rubber. Whole blood treated with heparin has been perfused through these capillaries. Under flowing conditions, no clotting or other clumping effects have been observed and red cells appear to maintain a constant velocity. Oxygen transfer data to and from saline perfusing the 12.5 mu diameter capillaries have been obtained in order to determine how rapidly O2 will permeate the silicone rubber film. The data indicate that the capillaries simulate lung tissue oxygen exchange and will allow for the first time the experimental determination of oxygen exchange kinetics in flowing whole blood.

  19. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  20. Capillary electrophoresis and nanomaterials - Part I: Capillary electrophoresis of nanomaterials.

    PubMed

    Adam, Vojtech; Vaculovicova, Marketa

    2017-10-01

    Nanomaterials are in analytical science used for a broad range of purposes, covering the area of sample pretreatment as well as separation, detection, and identification of target molecules. This part of the review covers capillary electrophoresis (CE) of nanomaterials and focuses on the application of CE as a method for characterization used during nanomaterial synthesis and modification as well as the monitoring of their properties and interactions with other molecules. The heterogeneity of the nanomaterial family is extremely large. Depending on different definitions of the term Nanomaterial/Nanoparticle, the group may cover metal and polymeric nanoparticles, carbon nanomaterials, liposomes and even dendrimers. Moreover, these nanomaterials are usually subjected to some kind of surface modification or functionalization, which broadens the diversity even more. Not only for purposes of verification of nanomaterial synthesis and batch-to-batch quality check, but also for determination the polydispersity and for functionality characterization on the nanoparticle surface, has CE offered very beneficial capabilities. Finally, the monitoring of interactions between nanomaterials and other (bio)molecules is easily performed by some kind of capillary electromigration technique. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. High pressure pulsed capillary viscometry

    NASA Technical Reports Server (NTRS)

    Smith, R. L.; Walowitt, J. A.; Pan, C. H. T.

    1972-01-01

    An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

  2. Capillary wave spectroscopy on ferrofluids

    NASA Astrophysics Data System (ADS)

    Patzke, J.; Rathke, B.; Will, S.

    2007-12-01

    We investigate the magnetoviscous effect in ferrofluids by Capillary Wave Spectroscopy (CWS, Surface Light Scattering). This technique probes a specific mode of thermally excited surface waves giving information on surface tension and viscosity. In ferrofluids we detect a transition from propagating surface modes to overdamped ones depending on the particle concentration and strength and the orientation of an externally applied magnetic field. We interprete this effect as caused by an increase of the liquid viscosity with an increasing particle concentration and field-strength. Changing the relative orientation of the scattering vector and magnetic field shows that the viscous properties of ferrofluids in a magnetic field are anisotropic. Figs 8, Refs 12.

  3. Horizontal microscopy in square capillaries

    NASA Astrophysics Data System (ADS)

    Moroz, Pavel E.

    1992-07-01

    Intracellular protoplasmic movements may, due to gravity, have a vertical component greater or different from the horizontal one. This makes horizontal microscopy indispensable in the search for the cellular sensor of gravity. The possibility of the latter being a cell organelle assigns special significance to high-resolution microscopy. A horizontal suction device for picking up a cell and its high-resolution horizontal microscopy in a rectangular capillary may be helpful for detection of gravity-related shifts of cellular organelles in vivo.

  4. Capillary Bridges between Soft Substrates

    NASA Astrophysics Data System (ADS)

    Wexler, Jason S.; Heard, Tiara M.; Stone, Howard A.

    2014-02-01

    A wetting droplet trapped in the thin gap between two elastic bodies will deflect the bodies towards one another. The deformation increases the total capillary adhesion force by increasing the contact radius and narrowing the gap height. For flat droplets, with a large ratio of radius to gap height, the Laplace pressure causes surface deformations that are orders of magnitude larger than those induced by a sessile droplet of the same radius. We present experiments, scalings, and closed-form solutions that describe the deformation. Using variational techniques, we also show that the problem exhibits a bifurcation, where the gap spontaneously closes due to an incremental increase in drop volume.

  5. Determination of Dihydroqinghaosu in Blood by Pyrolysis Gas Chromatography/Mass Spectrometry

    DTIC Science & Technology

    1988-01-15

    capillary the therapeutic range, our laboratory sought to develop new column gas chromatography/mass spectrometry ( GCMS ) specific and sensitive methodologies...paper, the results on the development and validation of packed for pharmacoklneUc an metabolism studies In animals. and capillary column gas...respectively. Petroleum ether washave been treated with QHS or its derivatives in China with purchased from Mallinckrodt, Inc. (Paris, KY), and ethyl acetate

  6. Immunoaffinity screening with capillary electrochromatography.

    PubMed

    Mayer, Michael; Muscate-Magnussen, Angelika; Vogel, Horst; Ehrat, Markus; Bruin, Gerard J M

    2002-05-01

    Highly efficient capillary electrochromatographic separations of cardiac glycosides and other steroids are presented. Employing butyl-derivatized silica particles as stationary phase resulted in a nearly three times faster electroosmotic flow (EOF) compared to capillary electrochromatography (CEC) with octadecyl silica particles. On-column focusing with a preconcentration factor of 180 was performed and separation efficiencies of up to 240,000 plates per meter were obtained. Using label-free standard UV absorbance, detection limits of 10-80 nM were reached for all steroids tested. For screening of cardiac glycosides, e.g., digoxin and digitoxin in mixtures of steroids, CEC was combined with immunoaffinity extraction using immobilized polyclonal anti-digoxigenin antibodies and F(ab) fragments. Simply adding small amounts of antibody carrying particles to the samples and comparing chromatograms before and after antibody addition allowed screening for high affinity antigens in mixtures with moderate numbers of compounds. Under conditions of competing antigens, affinity fingerprints of immobilized anti-digoxigenin and anti-digitoxin antibodies were obtained, reflecting the cross-reactivity of eleven steroids. The method provides high selectivity due to the combination of bioaffinity interaction with highly efficient CEC separation and UV detection at several wavelengths in parallel. This selectivity was exploited for the detection of four cardiac glycosides in submicromolar concentrations in an untreated urine sample.

  7. Cryogenic Capillary Screen Heat Entrapment

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L.G.; Hastings, L.J.; Stathman, G.

    2007-01-01

    Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of sub-cooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs.?"Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 data it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

  8. 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 & nanophotoni