Science.gov

Sample records for capillary electrochromatography-mass spectrometry

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

    PubMed

    Bragg, William; Shamsi, Shahab A

    2011-12-01

    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 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. PMID:22035695

  2. Capillary electrochromatography-mass spectrometry for the determination of 5-nitroimidazole antibiotics in urine samples.

    PubMed

    Hernández-Mesa, Maykel; D'Orazio, Giovanni; Rocco, Anna; García-Campaña, Ana M; Blanco, Carmen Cruces; Fanali, Salvatore

    2015-10-01

    The separation of eight antibiotics belonging to 5-nitroimidazole family was carried out by means of CEC coupled with MS. Preliminary experiments were carried out with ultraviolet detection in order to select the proper stationary and mobile phase. Among the different stationary phases studied (namely Lichrospher C18, 5 μm particle size; Cogent(TM) Bidentate C18, 4.2 μm; Pinnacle II™ Phenyl, 3 μm; Pinnacle II™ Cyano, 3 μm), Cogent™ Bidentate C18 (4.2 μm) gave the best performance. For CEC-MS coupling, a laboratory assembled liquid-junction-nano-spray interface was used. In order to achieve a good sensitivity, special attention was paid to both optimization of the sheath liquid composition as well as selection of the injection mode. Under optimized CEC-ESI-MS conditions, the separation was accomplished within 22 min by using a column packed with a mixture of Bidentate C18:Lichrospher Silica-60 (5 μm) 3:1 w/w, an inlet pressure of 11 bar, a voltage of 15 kV, and a mobile phase composed by 45:10:45 v/v/v ACN/MeOH/water containing ammonium acetate (5 mM pH 5). A combined hydrodynamic and electrokinetic injection of 8 bar, 15 kV, and 96 s was adopted. The method was validated in terms of repeatability and intermediate precision of retention times and peak areas, linearity, and LODs and LOQs. RSDs values were <2.9% for retention times and <16.1% for peak areas in both intraday and interday experiments. LOQ values were between 0.09 and 0.42 μg/mL for all compounds. Finally, the method was applied to the determination of three most employed 5-nitroimidazole antibiotics (metronidazole, secnidazole, and ternidazole) in spiked urine samples, subjected to a SPE procedure. Recovery values in the 67-103% range were obtained. Furthermore, for the selected antibiotics, CEC-MS(2) spectra were obtained providing the unambiguous confirmation of these drugs in urine samples. PMID:26200811

  3. Capillary electrophoresis electrospray ionization mass spectrometry interface

    SciTech Connect

    Smith, R.D.; Severs, J.C.

    1999-11-30

    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 analyte 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.

  4. 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.

  5. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect

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

    2014-06-17

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

  6. ANALYSIS OF HAZARDOUS WASTE AND ENVIRONMENTAL EXTRACTS BY CAPILLARY GAS CHROMATOGRAPHY/FOURIER TRANSFORM INFRARED SPECTROMETRY AND CAPILLARY GAS CHROMATOGRAPHY/MASS SPECTROMETRY

    EPA Science Inventory

    The relative sensitivities of fused-silica capillary column gas chromatography/Fourier transform infrared spectrometry (FSCC/GC/FT-IR) versus packed-column GC/FT-IR and FSCC/GC/FT-IR versus fused-silica capillary column gas chromatography/mass spectrometry (FSCC/GC/MS) were compa...

  7. 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. PMID:25715054

  8. 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.

  9. Quantitative Proteomics Using Ultralow Flow Capillary Electrophoresis–Mass Spectrometry

    PubMed Central

    2015-01-01

    In this work, we evaluate the incorporation of an ultralow flow interface for coupling capillary electrophoresis (CE) and mass spectrometry (MS), in combination with reversed-phase high-pressure liquid chromatography (HPLC) fractionation as an alternate workflow for quantitative proteomics. Proteins, extracted from a SILAC (stable isotope labeling by amino acids in cell culture) labeled and an unlabeled yeast strain were mixed and digested enzymatically in solution. The resulting peptides were fractionated using RP-HPLC and analyzed by CE–MS yielding a total of 28 538 quantified peptides that correspond to 3 272 quantified proteins. CE–MS analysis was performed using a neutral capillary coating, providing the highest separation efficiency at ultralow flow conditions (<10 nL/min). Moreover, we were able to demonstrate that CE–MS is a powerful method for the identification of low-abundance modified peptides within the same sample. Without any further enrichment strategies, we succeeded in quantifying 1 371 phosphopeptides present in the CE–MS data set and found 49 phosphopeptides to be differentially regulated in the two yeast strains. Including acetylation, phosphorylation, deamidation, and oxidized forms, a total of 8 106 modified peptides could be identified in addition to 33 854 unique peptide sequences found. The work presented here shows the first quantitative proteomics approach that combines SILAC labeling with CE–MS analysis. PMID:25839223

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. Capillary photoionization: a high sensitivity ionization method for mass spectrometry.

    PubMed

    Haapala, Markus; Suominen, Tina; Kostiainen, Risto

    2013-06-18

    We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R(2) > 0.993), limits of detection (LOD) in the range of 2-6 pg/mL and repeatability of injection with relative standard deviations of 4-15%. PMID:23713722

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

    PubMed

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

    2013-10-24

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

  16. Characterization of the microdialysis junction interface for capillary electrophoresis/microelectrospray ionization mass spectrometry

    SciTech Connect

    Severs, J.C.; Smith, R.D.

    1997-06-01

    A capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS) interface, based on an electric circuit across a microdialysis membrane surrounding a short capillary segment closely connected to the separation capillary terminus, is demonstrated to be sensitive, efficient, and rugged. A microspray type ionization emitter produces a stable electrospray at the low flow rates provided by CE and thus avoids both the need for a makeup liquid flow provided by liquid junction or sheath flow interfaces and the subsequent dilution and reduction in sensitivity. Reproducibility studies and comparisons with CE/UV and the CE/sheath flow interface with ESI-MS are presented. Additionally, postrun acidification via the microdialysis junction interface is demonstrated and shown to be capable of denaturing the holomyoglobin protein noncovalent complex while maintaining separation efficiency. 21 refs., 7 figs., 1 tab.

  17. The characterization of snake venoms using capillary electrophoresis in conjunction with electrospray mass spectrometry: Black Mambas.

    PubMed

    Perkins, J R; Parker, C E; Tomer, K B

    1993-01-01

    Capillary electrophoresis has been used in conjunction with electrospray mass spectrometry using both full-scan and selected ion monitoring modes to supply as much information as possible about the venom of Dendroaspis polylepis polylepis (Black Mamba). As an example of the application of capillary electrophoresis/electrospray mass spectrometry (CE/ESI/MS) to the analysis of a complex mixture of small proteins, we have analyzed the venom of Dendroaspis polylepis polylepis using the combined techniques. Both full-scan and selected ion monitoring modes were employed. CE/ESI/MS provides a rapid and extremely sensitive method for molecular weight determination, particularly when selected ion monitoring is employed. It has been utilized to provide sequence confirmation for those toxins which have already been described in the literature. Our methodology indicates the presence of at least 70 peptides in the molecular weight range 6000-9000. PMID:8354229

  18. 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. PMID:26521181

  19. Two-dimensional separation of ionic species by hyphenation of capillary ion chromatography × capillary electrophoresis-mass spectrometry.

    PubMed

    Beutner, Andrea; Kochmann, Sven; Mark, Jonas Josef Peter; Matysik, Frank-Michael

    2015-03-17

    The separation of complex mixtures such as biological or environmental samples requires high peak capacities, which cannot be established with a single separation technique. Therefore, multidimensional systems are in demand. In this work, we present the hyphenation of the two most important (orthogonal) techniques in ion analysis, namely, ion chromatography (IC) and capillary electrophoresis (CE), in combination with mass spectrometry. A modulator was developed ensuring a well-controlled coupling of IC and CE separations. Proof-of-concept measurements were performed using a model system consisting of nucleotides and cyclic nucleotides. The data are presented in a multidimensional contour plot. Analyte stacking in the CE separation could be exploited on the basis of the fact that the suppressed IC effluent is pure water. PMID:25708415

  20. 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. PMID:16804601

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

    PubMed

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

    2015-10-16

    A capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) method for the simultaneous assessment of nine biogenic amines (spermine, spermidine, putrescine, cadaverine, histamine, phenylethylamine, tryptamine, tyramine, and urocanic acid) in commercial samples of beer and wine is introduced. The samples were submitted to a simple clean-up step with poly(vinylpolypyrrolidone) followed by filtration. Electrophoretic separation in a polyvinyl alcohol (PVA)-coated capillary using 0.5 mol L(-1) acetic acid (pH 2.5) as background electrolyte and detection by electrospray-tandem mass spectrometry was employed. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.996-0.999, and the limits of detection and limits of quantification were in the range of 1-2 μg L(-1) and 3-8 μg L(-1), respectively. The recovery values for samples spiked at three concentration levels (0.2, 0.5, and 1.0 mg L(-1)) ranged from 87 to 113% with standard deviation not greater than 5.8%. The use of a PVA-coated silica capillary allows suppressing the electroosmotic flow and, consequently, increasing of the separation efficiency. The method was successfully used to determine biogenic amines in commercial samples of beer and wine. PMID:26362807

  2. 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

  3. Analysis of glyphosate and glufosinate by capillary electrophoresis-mass spectrometry utilising a sheathless microelectrospray interface.

    PubMed

    Goodwin, Lee; Startin, James R; Keely, Brendan J; Goodall, David M

    2003-07-01

    The potential of capillary electrophoresis combined with mass spectrometry for the simultaneous determination of two herbicides (glyphosate and glufosinate) and their metabolites (aminomethylphosphonic acid and methylphosphinicopropionic acid) as the native species is demonstrated utilising a simple microelectrospray interface. The interface uses the voltage applied to the CE capillary to drive separation and generate the electrospray, avoiding sample dilution associated with the use of a sheath liquid interface. The chemistry of the internal walls of the capillary has a marked influence on peak shape, and appropriate choice is essential to successful operation of the interface. A linear polyacrylamide coated capillary, which has no electroosmotic flow, gave best reproducibility, with precision of migration time and peak area in the range 1-2 and 7-12% RSD, respectively, for the four analytes. Limits of detection, low-pg on-column, are substantially better than for previous methods and calibration curves over the range 1-100 microM have R2 values greater than 0.97. The observed concentration limit of detection for glyphosate in water is 1 microM and for a water-acetone extract of wheat is 2.5 microM, allowing the underivatised herbicide to be detected at 10% of the maximum residue limit in wheat. PMID:12929967

  4. On-line coupling of capillary gel electrophoresis with electrospray mass spectrometry for oligonucleotide analysis.

    PubMed

    Freudemann, T; von Brocke, A; Bayer, E

    2001-06-01

    Homooligodeoxyribonucleotides differing one nucleotide in length from 12- to 15-mer and from 17- to 20-mer were separated by size with capillary gel electrophoresis (CGE) using an entangled polymer solution in coated capillaries. The resolved components were analyzed by on-line coupling of CGE with electrospray mass spectrometry (ES-MS), denoted as CGE/ES-MS, in the full-scan negative ion detection mode. Baseline separation was achieved for the 12-15-mer oligonucleotide mixtures. Both synthetic phosphodiester oligonucleotide mixtures as well as their phosphorothioate analogues, serving as model compounds for antisense oligonucleotides, could be analyzed by on-line CGE/ES-MS coupling. Terminally phosphorylated and nonphosphorylated synthetic failure sequences could be electrophoretically separated and mass spectrometically characterized as well. This methodology might be a useful tool for synthesis control of phosphodiester oligonucleotides as well as for analysis of phosphorothioate analogues as they are used in antisense drug development. PMID:11403304

  5. 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.

  6. Development of a simple vent-free interface for capillary gas chromatography-mass spectrometry.

    PubMed

    Watanabe, Chuichi; Takeda, Shihori; Freeman, Robert R; Ohtani, Hajime

    2011-01-01

    A novel and simple interface for capillary gas chromatography-mass spectrometry (GC-MS) was developed using a piece of deactivated stainless-steel tubing. This interface eliminated the need to vent the MS ion source when changing columns. Various chromatographic performance indicators, such as inertness, and thermal and chemical stability, were confirmed to be unaffected by using this interface at an elevated temperature of around 300°C. The new interface should facilitate the characterization of polymeric materials using analytical pyrolysis techniques in which frequent switching is required in the measuring mode, such as evolved gas analysis-MS and flash pyrolysis-GC-MS. PMID:22076334

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

    PubMed

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

    2016-09-01

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

  8. PRECISION AND ACCURACY IN THE DETERMINATION OF ORGANICS IN WATER BY FUSED SILICA CAPILLARY COLUMN GAS CHROMOTOGRAPHY/MASS SPECTROMETRY AND PACKED COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY

    EPA Science Inventory

    Two general methods for the identification and measurement of organic compounds in water are compared. One method employs packed column chromatography and the other fused silica capillary column chromatography. The two gas chromatography/mass spectrometry (GC/MS) methods use diff...

  9. Evaluation of a novel hydrophilic derivatized capillary for protein analysis by capillary electrophoresis-electrospray mass spectrometry.

    PubMed

    Cole, R B; Varghese, J; McCormick, R M; Kadlecek, D

    1994-10-01

    A new type of hydrophilic derivatized capillary has been used to enable the on-line capillary electrophoresis separation and electrospray mass spectrometric detection of a mixture of proteins containing bovine cytochrome c, tuna cytochrome c and horse heart myoglobin. Less than 40 fmol of each compound were loaded into the capillary. Baseline resolution of components was achieved, as were accurate assignments of molecular masses. The hydrophilic derivatized capillaries were taken through extensive testing procedures to characterize their performance and capabilities for protein analysis. A mixture of six proteins (cytochrome c, ribonuclease A, alpha-chymotrypsinogen, myoglobin, carbonic anhydrase II and alpha-lactalbumin) in acetic acid-sodium acetate buffer was used to delineate the relationships between migration time and pH, along with migration time and buffer concentration for each protein. The variations in capillary efficiency as a function of pH and as a function of buffer concentration were also characterized for the same six proteins in the acetic acid-sodium acetate system. A pH of 4.8 was found to offer an excellent compromise between separation efficiency (up to 500,000 theoretical plates) and analysis time. Capillary efficiencies were also found to be very good when employing a Tris.HCl electrolyte adjusted to pH 4.8. Lastly, electropherogram reproducibility and capillary durability were examined with the finding that little deterioration of the capillary occurred over the course of 400 injections (200 h run time). This represents a notable improvement over previously documented derivatization procedures designed to reduce protein adsorption to fused-silica capillary walls. PMID:7981821

  10. Ultrasensitive determination of 5-methylcytosine and 5-hydroxymethylcytosine in genomic DNA by sheathless interfaced capillary electrophoresis-mass spectrometry.

    PubMed

    Yuan, Fang; Zhang, Xiao-Hui; Nie, Ji; Chen, Hong-Xu; Zhou, Ying-Lin; Zhang, Xin-Xiang

    2016-02-14

    A newly developed sheathless interface for capillary electrophoresis-mass spectrometry, using a porous tip sprayer, was first applied for highly sensitive determination of cytosine modifications. The system performed well in identification and quantification of both 5-methylcytosine and 5-hydroxymethylcytosine using only 125 pg (∼20 cells) genomic DNA samples. PMID:26753520

  11. 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 ...

  12. On-line screening of matrix metalloproteinase inhibitors by capillary electrophoresis coupled to ESI mass spectrometry.

    PubMed

    Wang, Xu; Dou, Zhiying; Yuan, Yaozuo; Man, Shuli; Wolfs, Kris; Adams, Erwin; Van Schepdael, Ann

    2013-07-01

    Capillary electrophoresis (CE) with the use of mass spectrometry (MS) has been considered as a unique tool for microscale enzyme assay and inhibitor screening. In this study, matrix metalloproteinase-9 (MMP-9) was selected as target enzyme due to its important role in tumor invasion and metastasis. In order to define the optimal MS parameters, a two level half fraction factorial experimental design was performed. A background electrolyte consisting of 20mM ammonium acetate (pH 6.8) and a sheath liquid of water-methanol (50:50, v/v) containing 0.05% formic acid at a flow rate of 4μl/min were selected. This system was operated in the positive ion mode with a detection-limit of 10nM for the MMP reaction product and provided 60 folds enhancement of sensitivity by using selected reaction monitoring detection compared with MS full scan mode, which significantly increased the detectability of the system and therefore reduced the enzyme reaction time in both off-line and in-line mode. Both electrophoretically mediated microanalysis and pressure mediated microanalysis combined with MS detection were investigated for MMP inhibitor screening. Good repeatability (RSD of peak area and migration time were lower than 5.0%) and linearity (R(2)>0.996) were obtained for both in-capillary approaches. Several tetracycline antibiotics and natural products were selected to test the system. The results indicated an agreement on the ranking of inhibitory potency for both in-capillary approaches. PMID:23727866

  13. 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

  14. 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

  15. Detection of Amadori compounds by capillary electrophoresis coupled to tandem mass spectrometry.

    PubMed

    Hau, Jörg; Devaud, Stéphanie; Blank, Imre

    2004-07-01

    Capillary electrophoresis coupled to mass spectrometry (CE-MS) is reported for the first time as an alternative and powerful analytical method for the characterization and monitoring of N-substituted 1-amino-1-deoxyketoses (Amadori compounds). It allows rapid separation and identification of Amadori compounds, while benefiting from the well-known advantages of MS, such as specificity and sensitivity. Amadori compounds of several amino acids, such as glycine, valine, isoleucine, methionine, proline, and phenylalanine, as well as a cysteine-derived compound, were separated and/or discriminated using CE-MS/MS under standard conditions. The technique may also be useful to study the stability and degradation kinetics of other labile charged Maillard intermediates that play an important role in food and medical science. PMID:15237408

  16. 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.

  17. Analysis of endogenous nucleotides by single cell capillary electrophoresis-mass spectrometry

    PubMed Central

    Liu, Jing-Xin; Aerts, Jordan T.; Rubakhin, Stanislav S.; Zhang, Xin-Xiang; Sweedler, Jonathan V.

    2015-01-01

    Analytical technologies that enable investigations at the single cell level facilitate a range of studies; here a lab-fabricated capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) platform was used to analyze anionic metabolites from individual Aplysia californica neurons. The system employs a customized coaxial sheath-flow nanospray interface connected to a separation capillary, with the sheath liquid and separation buffer optimized to ensure a stable spray. The method provided good repeatability of separation and reliable detection sensitivity for 16 mono-, di- and triphosphate nucleosides. For a range of anionic analytes, including cyclic adenosine monophosphate (cAMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP), the detection limits were in the low nanomolar range (<22 nM). A large Aplysia R2 neuron was used to demonstrate the ability of CE-ESI-MS to quantitatively characterize anionic metabolites within individual cells, with 15 nucleotides and derivatives detected. Following the method validation process, we probed smaller, 60-μm diameter Aplysia sensory neurons where sample stacking was used as a simple on-line analyte preconcentration approach. The calculated energy balance ([ATP] + 0.5 × [ADP])/([AMP] + [ADP] + [ATP]) of these cells was comparable with the value obtained from bulk samples. PMID:25212237

  18. A new sheathless electrospray interface for coupling of capillary electrophoresis to ion-trap mass spectrometry.

    PubMed

    Bendahl, Lars; Hansen, Steen Honoré; Olsen, Jørgen

    2002-01-01

    A simple laboratory-made sheathless electrospray interface for coupling of capillary electrophoresis to ion-trap mass spectrometry (CE/MS) was developed. The interface was machined in-house and it was designed to be freely interchangeable with the commercially available ionization sources for the mass spectrometer. Sharpened fused-silica capillaries were coated with nickel by a simple electrodeless plating procedure and were used as all-in-one columns/emitters. The electrodeless plating produced a 2-5- micro m thick smooth nickel layer that lasted for more than 8 h of continuous electrospraying. The performance of the CE/MS interface was examined by using four cationic imipramine derivatives as test substances. Relative detection limits were calculated on the basis of the extracted ion electrophorograms and were in the range 6-130 nmol/L, corresponding to absolute detection limits in the range of 20-400 amol. The system was applied for analysis of impurities in an impure imipramine N-oxide preparation, and two of the impurities could be identified on the basis of online-MS(MS) spectra recorded in scan-dependent mode. PMID:12478579

  19. Analysis of isoquinoline alkaloids in medicinal plants by capillary electrophoresis-mass spectrometry.

    PubMed

    Sturm, S; Stuppner, H

    1998-11-01

    The technique of capillary electrophoresis - mass spectrometry (CE-MS) was applied for determination of isoquinoline alkaloids in crude methanolic extracts of medicinal plants. For the CE separations ammonium formate buffer solutions (70 or 100 mM, pH 3.0 or 4.0) containing 10% methanol or 20-60% acetonitrile as additives were used. The applied voltage was 25 kV, the thermostating temperature was kept constant at 25 degrees C. Coupling with the mass spectrometer was performed via an atmospherical pressure ionization (API) interface and the electrospray ionization technique (ESI). As sheath liquid 5 mM formic acid in acetonitrile at a flow rate of 3 microL/min was used. The spray voltage was 4.5 kV and the temperature of the heated capillary was chosen to be 200 degrees C. Detection in the positive ionization mode resulted in mass spectra showing either the molecular ions [M]+ or the protonated molecular ions [M+H]+. The presented method allows detection and identification of isoquinoline alkaloids in crude methanolic extracts of medicinal plants as Eschscholzia californica CHAM. (Papaveraceae), Hydrastis canadensis L. (Ranunculaceae), Berberis vulgaris L. (Berberidaceae), Jateorhiza palmata (LAM.) MIERS (Menispermaceae) and Chelidonium majus L. (Papaveraceae). PMID:9870408

  20. 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

  1. Capillary Liquid Chromatography Mass Spectrometry Analysis of Intact Monolayer-Protected Gold Clusters in Complex Mixtures.

    PubMed

    Black, David M; Bach, Stephan B H; Whetten, Robert L

    2016-06-01

    In some respects, large noble-metal clusters protected by thiolate ligands behave as giant molecules of definite composition and structure; however, their rigorous analysis continues to be quite challenging. Analysis of complex mixtures of intact monolayer-protected clusters (MPCs) by liquid chromatography mass spectrometry (LC-MS) could provide quantitative identification of the various components present. This advance is critical for biomedical and toxicological research, as well as in fundamental studies that rely on the identification of selected compositions. This work expands upon the separate LC and MS results previously achieved, by interfacing the capillary liquid chromatograph directly to the electrospray source of the mass spectrometer, in order to provide an extremely sensitive, quantitative, and rapid means to characterize MPCs and their derivatives far beyond that of earlier reports. Here, we show that nonaqueous reversed-phase chromatography can be coupled to mass-spectrometry detection to resolve complex mixtures in minute (∼100 ng) samples of gold MPCs, of molecular masses up to ∼40 kDa, and with single-species sensitivity easily demonstrated for components on the level of sub-10 ng or picomole (1 pmol). PMID:27216373

  2. Imaging MALDI mass spectrometry of sphingolipids using an oscillating capillary nebulizer matrix application system.

    PubMed

    Chen, Yanfeng; Liu, Ying; Allegood, Jeremy; Wang, Elaine; Cachón-González, Begoña; Cox, Timothy M; Merrill, Alfred H; Sullards, M Cameron

    2010-01-01

    Matrix deposition is a critical step in tissue imaging by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). It greatly affects the quality of MALDI imaging, especially for the analytes (such as lipids) that may easily dissolve in the solvent used for the matrix application. This chapter 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 protocol allows visualization of many different lipid species and, of particular interest, sphingolipids in tissue slices of Tay-Sachs/Sandhoff disease by imaging MALDI-MS. The structures of these lipids were identified by analysis of tissue extracts using electrospray ionization in conjunction with tandem mass spectrometry (MS/MS and MS(3)). These results illustrate the usefulness of tissue imaging MALDI-MS with matrix deposition by OCN for the molecular analysis in normal physiology and pathology. In addition, the observation of numerous lipid subclasses with distinct localizations in the brain slices demonstrates that imaging MALDI-MS could be effectively used for "lipidomic" studies. PMID:20680588

  3. 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. PMID:25681206

  4. Quantitative confirmation of dimetridazole and ipronidazole in swine feed by capillary gas chromatography/mass spectrometry with multiple ion detection.

    PubMed

    Morris, W J; Nandrea, G J; Roybal, J E; Munns, R K; Shimoda, W; Skinner, H R

    1987-01-01

    Extracts from 4 types of swine feed containing 0.11 ppm each of dimetridazole (DMZ) and ipronidazole (IPR) were analyzed by capillary gas chromatography/mass spectrometry (GC/MS) using multiple ion detection (MID) techniques. We demonstrate in this paper that the quantitative results obtained by capillary GC/MS with MID are comparable for both compounds to results obtained by liquid chromatography and have a lower coefficient of variation for DMZ. Moreover, consistency in the ion ratios (5 ions in DMZ and 6 ions in IPR) permits identification of these compounds by electron ionization MS. PMID:3624166

  5. Optimization of in-line fritless solid-phase extraction for capillary electrophoresis-mass spectrometry.

    PubMed

    Tak, Yvonne H; Toraño, Javier Sastre; Somsen, Govert W; de Jong, Gerhardus J

    2012-12-01

    In this study, in-line frit-free solid-phase extraction (SPE) has been studied for the preconcentration of analytes prior to analysis by capillary electrophoresis-mass spectrometry (CE-MS). The mixed-mode sorbent Oasis HLB was selected for the trapping of compounds of different polarity. Using 2-ethylidene-1,5-dimethyl-3,3-diphenylpirrolidine (EDDP), dihydrocodeine and codeine as test compounds, SPE parameters such as the pH of the sample and composition of the washing and elution solvent were optimized. Trapping of the analytes was optimal at pH 8.0 or higher. For efficient elution of the SPE micro column, 85% of methanol in water with 2% (v/v) acetic acid was used, which also prevented current break down in subsequent CE analysis. CE resolution of the test compounds was highest for background electrolytes (BGEs) with a pH above 8. For optimal analysis, samples were 1:1 diluted with carbonate buffer (1M, pH 8.0) prior to analysis, BGE was 60mM ammonium acetate buffer (pH 10.0), and the injected sample volume was 60 μl (i.e., 30 capillary volumes). Good recoveries were found: 101% for EDDP, 88% for codeine and 90% for dihydrocodeine. Intraday RSDs for migration time and peak areas were below 0.56% and 15%, respectively. Peak widths at half height obtained with SPE-CE-MS were 12s for EDDP, 3.7s for dihydrocodeine and 7.4s for codeine, and were comparable to those for CE-MS. LODs were 0.22 pg/ml for EDDP, 2.1 pg/ml for dihydrocodeine and 24 pg/ml for codeine. It is concluded that the applied fritless in-line preconcentration construct proved to be highly useful for improving the sensitivity of CE while maintaining separation. PMID:22959866

  6. 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. PMID:25749794

  7. 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. PMID:26644308

  8. 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.

  9. Analysis of methaqualone in biological matrices by micellar electrokinetic capillary chromatography. Comparison with gas chromatography-mass spectrometry.

    PubMed

    Plaut, O; Girod, C; Staub, C

    1998-04-01

    The analysis of methaqualone (MTQ) in biological matrices by capillary electrophoresis (CE) is described. This methods uses liquid-liquid extraction and micellar electrokinetic capillary chromatography (MECC), an operation mode of CE. Separations are made using a 25 cm long capillary and a borate/phosphate buffer at pH 8.2. Using gas chromatography with mass spectrometry detection (GC-MS) as reference method, MTQ has been analyzed in urine, blood, gastric content and hair. For hair analysis, supercritical fluid extraction was compared with liquid-liquid extraction. Linearity was established in urine and blood between 0.25 and 10.0 micrograms/ml. MTQ recovery from blood was estimated at 60%. The limit of detection of this method in urine is about 0.10 microgram/ml. Drawbacks and advantages of MECC over GC-MS are discussed. PMID:9627981

  10. 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

  11. Forensic analysis of mesembrine alkaloids in Sceletium tortuosum by nonaqueous capillary electrophoresis mass spectrometry.

    PubMed

    Roscher, Jörg; Posch, Tjorben Nils; Pütz, Michael; Huhn, Carolin

    2012-06-01

    The consumption of legal and illegal drugs follows an organic trend comparable to the current trend in food consumption. The investigation of such drugs is therefore of interest to characterize the active ingredients of plants and drug preparations. A new method of nonaqueous capillary electrophoresis coupled to mass spectrometry (NACE-MS) as a powerful tool for the separation of complex alkaloid mixtures in difficult matrices is presented in this study for the analysis of samples of Sceletium tortuosum and drug products called Kanna made thereof. The method was found to be suitable for the investigation of the alkaloid composition and relative quantification of the ingredients. It proved of value to separate a large number of isobaric compounds, most probably including diastereomers, double-bond isomers, and further structurally closely related compounds. A comparison of plant samples from different vendors, self-fermented samples, and products ready for consumption was made. The high separation power obtained allowed a better description of the chemotypic differences of plant samples as well as Kanna preparations compared to other methods presented in the literature so far. Thus, the use of the NACE-MS enables a new perspective on the alkaloid profile of Sceletium species. PMID:22736358

  12. Intact mass analysis of monoclonal antibodies by capillary electrophoresis-Mass spectrometry.

    PubMed

    Han, Mei; Rock, Brooke M; Pearson, Josh T; Rock, Dan A

    2016-02-01

    Characterization of monoclonal antibody (mAb) therapeutics by intact mass analysis provides important information on sequence integrity and post-translational modifications. In order to obtain domain specific information, monoclonal antibodies are reduced to heavy and light chain components or enzymatically digested into smaller portions or peptides. Liquid chromatography (LC) is widely used for separation of the antibody fragments in line with mass spectrometry (MS) for characterization. Capillary electrophoresis (CE) is an analytical technique with high separation efficiency, high sensitivity, and minimal inter-run sample carryover. Combining the resolving power of CE with electrospray ionization (ESI) MS has great potential in regards to accurate mass characterization of protein therapeutics and has been a long sought-after approach. However, the intrinsic technical difficulty in coupling CE to MS has hindered the broad application of CE-MS across the biopharmaceutical industry. Recently, a CE-MS interface has been developed [1] and commercialized. Herein, we report implementation of this technology for coupling CE to an Agilent time-of-flight (TOF) mass spectrometer. CE-MS provides an attractive complement to LC-MS for separation and intact mass determination of mAbs and antibody-based therapeutics. PMID:26751590

  13. Capillary electrophoresis-mass spectrometry as a new approach to analyze neonicotinoid insecticides.

    PubMed

    Sánchez-Hernández, Laura; Hernández-Domínguez, Deamelys; Bernal, José; Neusüß, Christian; Martín, María T; Bernal, José L

    2014-09-12

    This paper represents the first report of a capillary electrophoresis (CE) method compatible with mass spectrometry (MS) detection for simultaneously analyzing seven neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid and thiamethoxam). Different variables affecting CE separation (buffer concentration, pH, applied voltage and injection time) and MS detection (electrospray parameters) were studied. Low limits of detection (LOD) and quantification (LOQ) were achieved for all analytes, ranging from 1.0 to 2.3μg/L, and from 3.5 to 7.2μg/L, respectively. In addition, the proposed method showed itself to be linear in the range from LOQ to 1000μg/L and to be precise, as the relative standard deviations of the migration times were lower than 4% in all cases. Finally, the proposed CE-MS method was applied to assess the efficacy of a beeswax cleaning treatment with oxalic acid to remove residues of three of the most commonly used neonicotinoids (clothianidin, imidacloprid and thiamethoxam), use of which has recently been restricted by the European Union. PMID:25085817

  14. 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.

  15. Alignment of capillary electrophoresis-mass spectrometry datasets using accurate mass information.

    PubMed

    Nevedomskaya, Ekaterina; Derks, Rico; Deelder, André M; Mayboroda, Oleg A; Palmblad, Magnus

    2009-12-01

    Capillary electrophoresis-mass spectrometry (CE-MS) is a powerful technique for the analysis of small soluble compounds in biological fluids. A major drawback of CE is the poor migration time reproducibility, which makes it difficult to combine data from different experiments and correctly assign compounds. A number of alignment algorithms have been developed but not all of them can cope with large and irregular time shifts between CE-MS runs. Here we present a genetic algorithm designed for alignment of CE-MS data using accurate mass information. The utility of the algorithm was demonstrated on real data, and the results were compared with one of the existing packages. The new algorithm showed a significant reduction of elution time variation in the aligned datasets. The importance of mass accuracy for the performance of the algorithm was also demonstrated by comparing alignments of datasets from a standard time-of-flight (TOF) instrument with those from the new ultrahigh resolution TOF maXis (Bruker Daltonics). PMID:19826795

  16. Capillary electrophoresis-mass spectrometry determination of morphine and its isobaric glucuronide metabolites.

    PubMed

    Isbell, Theresa A; Strickland, Erin C; Hitchcock, Jennifer; McIntire, Gregory; Colyer, Christa L

    2015-02-01

    The determination of morphine and its isobaric metabolites morphine-3-beta-d-glucuronide (M3G) and morphine-6-beta-d-glucuronide (M6G) is useful for therapeutic drug monitoring and forensic identification of drug use. In particular, capillary electrophoresis with mass spectrometry (CE-MS) represents an attractive tool for opioid analysis. Whereas volatile background electrolytes in CE often improve electrospray ionization for coupled MS detection, such electrolytes may reduce CE separation efficiency and resolution. To better understand the effects of background electrolyte (BGE) composition on separation efficiency and detection sensitivity, this work compares and contrasts method development for both volatile (ammonium formate and acetate) and nonvolatile (ammonium phosphate and borate) buffers. Peak efficiencies and migration times for morphine and morphine metabolites were optimal with a 25mM ammonium borate buffer (pH=9.5) although greater sensitivities were achieved in the ammonium formate buffer. Optimized CE methods allowed for the resolution of the isobaric morphine metabolites prior to high mass accuracy, electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS detection applicable to the analysis of urine samples in under seven minutes. Urine sample preparation required only a 10-fold dilution with BGE prior to analysis. Limits of detection (LOD) in normal human urine were found to be 1.0μg/mL for morphine and 2.5μg/mL for each of M3G and M6G by CE-ESI-QTOF-MS. These LODs were comparable to those for CE-UV analysis of opioid standards in buffer, whereas CE-ESI-QTOF-MS analysis of opioid standards in buffer yielded LODs an order of magnitude lower. Patient urine samples (N=12) were analyzed by this new CE-ESI-QTOF-MS method and no significant difference in total morphine content relative to prior liquid chromatography-mass spectrometry (LC-MS) results was found as per a paired-t test at the 99% confidence level. Whereas the LC-MS method applied

  17. Monoclonal antibodies biosimilarity assessment using transient isotachophoresis capillary zone electrophoresis-tandem mass spectrometry.

    PubMed

    Gahoual, Rabah; Biacchi, Michaël; Chicher, Johana; Kuhn, Lauriane; Hammann, Philippe; Beck, Alain; Leize-Wagner, Emmanuelle; François, Yannis N

    2014-01-01

    Out of all categories, monoclonal antibody (mAb) therapeutics attract the most interest due to their strong therapeutic potency and specificity. Six of the 10 top-selling drugs are antibody-based therapeutics that will lose patent protection soon. The European Medicines Agency has pioneered the regulatory framework for approval of biosimilar products and approved the first biosimilar antibodies by the end of 2013. As highly complex glycoproteins with a wide range of micro-variants, mAbs require extensive characterization through multiple analytical methods for structure assessment rendering manufacturing control and biosimilarity studies particularly product and time-consuming. Here, capillary zone electrophoresis coupled to mass spectrometry by a sheathless interface (CESI-MS) was used to characterize marketed reference mAbs and their respective biosimilar candidate simultaneously over different facets of their primary structure. CESI-MS/MS data were compared between approved mAbs and their biosimilar candidates to prove/disconfirm biosimilarity regarding recent regulation directives. Using only a single sample injection of 200 fmol, CESI-MS/MS data enabled 100% amino acids (AA) sequence characterization, which allows a difference of even one AA between 2 samples to be distinguished precisely. Simultaneously glycoforms were characterized regarding their structures and position through fragmentation spectra and glycoforms semiquantitative analysis was established, showing the capacity of the developed methodology to detect up to 16 different glycans. Other posttranslational modifications hotspots were characterized while their relative occurrence levels were estimated and compared to biosimilars. These results proved the value of using CESI-MS because the separation selectivity and ionization efficiency provided by the system allowed substantial improvement in the characterization workflow robustness and accuracy. Biosimilarity assessment could be performed

  18. Monoclonal antibodies biosimilarity assessment using transient isotachophoresis capillary zone electrophoresis-tandem mass spectrometry

    PubMed Central

    Gahoual, Rabah; Biacchi, Michaël; Chicher, Johana; Kuhn, Lauriane; Hammann, Philippe; Beck, Alain; Leize-Wagner, Emmanuelle; François, Yannis N

    2014-01-01

    Out of all categories, monoclonal antibody (mAb) therapeutics attract the most interest due to their strong therapeutic potency and specificity. Six of the 10 top-selling drugs are antibody-based therapeutics that will lose patent protection soon. The European Medicines Agency has pioneered the regulatory framework for approval of biosimilar products and approved the first biosimilar antibodies by the end of 2013. As highly complex glycoproteins with a wide range of micro-variants, mAbs require extensive characterization through multiple analytical methods for structure assessment rendering manufacturing control and biosimilarity studies particularly product and time-consuming. Here, capillary zone electrophoresis coupled to mass spectrometry by a sheathless interface (CESI-MS) was used to characterize marketed reference mAbs and their respective biosimilar candidate simultaneously over different facets of their primary structure. CESI-MS/MS data were compared between approved mAbs and their biosimilar candidates to prove/disconfirm biosimilarity regarding recent regulation directives. Using only a single sample injection of 200 fmol, CESI-MS/MS data enabled 100% amino acids (AA) sequence characterization, which allows a difference of even one AA between 2 samples to be distinguished precisely. Simultaneously glycoforms were characterized regarding their structures and position through fragmentation spectra and glycoforms semiquantitative analysis was established, showing the capacity of the developed methodology to detect up to 16 different glycans. Other posttranslational modifications hotspots were characterized while their relative occurrence levels were estimated and compared to biosimilars. These results proved the value of using CESI-MS because the separation selectivity and ionization efficiency provided by the system allowed substantial improvement in the characterization workflow robustness and accuracy. Biosimilarity assessment could be performed

  19. 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. PMID:15237406

  20. 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

  1. 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. PMID:25679984

  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. Characterization of a capillary zone electrophoresis/electrospray-mass spectrometry interface.

    PubMed

    Siethoff, C; Nigge, W; Linscheid, M

    1998-04-01

    A dependable and stable CZE/ESI-MS interface has been constructed. To avoid instabilities in both, the capillary electrophoretic separation and the electrospray, the second of the three concentric capillaries in the three-layered sprayer has been replaced by an aluminum-coated fused-silica capillary with an inner diameter only slightly greater than the outer diameter of the separation capillary. By this means, the otherwise often observed destruction of the separation capillary ("electrodrilling") can be avoided completely due to the suppression of electrochemical processes leading to gas bubble formation at the tip of the sprayer. With some examples taken from different biochemical areas and by separation of natural compounds, the capability and the reliability of the modified sprayer as the central part of the interface are demonstrated. PMID:21644732

  4. A soft on-column metal coating procedure for robust sheathless electrospray emitters used in capillary electrophoresis-mass spectrometry.

    PubMed

    Trapp, Oliver; Pearce, Evan W; Kimmel, Joel R; Yoon, Oh Kyu; Zuleta, Ignacio A; Zare, Richard N

    2005-04-01

    An on-column metal coating procedure was developed for sheathless electrospray emitters, based on Justus von Liebig's electroless silver mirror reaction followed by electrochemical deposition of gold onto the silver layer. The coating procedure is straightforward, mild, inexpensive, and can be performed with standard laboratory equipment. A long-term (600 h) stability investigation of the conductive coating was carried out by continuous electrospray in the positive electrospray mode, and no degradation in performance was found. The simplicity of the coating procedure and the robustness of the spray tips makes the spray tips highly suitable to couple delicate wall-coated or monolithic capillary columns to mass spectrometry. Peptide mixtures were separated by capillary electrophoresis and injected into either a Hadamard-transform time-of-flight mass analyzer or a commercial quadrupole mass analyzer using the described sheathless electrospray emitters. The performance was judged to be excellent. PMID:15759300

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

    PubMed Central

    Chen, Zhi; Weber, Stephen G.

    2008-01-01

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

  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. PMID:22284496

  7. 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.

  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. 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...

  10. Electrospray ionization phenomena and the interface of capillary electrophoresis and mass spectrometry. [Quaternary phosphonium salts

    SciTech Connect

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

    1988-06-01

    Recently a new electrospray ionization interface for capillary electrophoresis-mass spectroscopy (CE-MS) has been developed. The interface uses a sheath flow of liquid to make electrical contact at the CZE terminus, thus defining both the CZE and electrospray field gradients. Ions created by the ESI process are sampled through a 1 mm nozzle into a region mechanically pumped at 50 L/s using a single-stage roots blower. The ions entering this region are sampled through a 2 mm dia skimmer orifice located 0.5 cm behind the nozzle orifice. Ions passing through the skimmer enter a radio frequency focusing quadrupole. This region is pumped by a cryopump. A mixture of four quaternary phosphonium salts is used to illustrate capillary electrophoresis separations with mass spectroscopy and their uses. 2 figs.

  11. Capillary ion chromatography-mass spectrometry for simultaneous determination of glucosylglycerol and sucrose in intracellular extracts of cyanobacteria.

    PubMed

    Fa, Yun; Liang, Wenhui; Cui, He; Duan, Yangkai; Yang, Menglong; Gao, Jun; Liu, Huizhou

    2015-09-15

    A capillary ion chromatography-mass spectrometry (MS) method was proposed to determine glucosylglycerol (GG), sucrose, and five other carbohydrates. MS conditions and make-up flow parameters were optimized. This method is accurate and sensitive for simultaneous analysis of carbohydrates, with mean correlation coefficients of determination greater than 0.99, relative standard deviation of 0.91-2.81% for eight replicates, and average spiked recoveries of 97.3-104.9%. Limits of detection of sodium adduct were obtained with MS detection in selected ion mode for GG (0.006mg/L), sucrose (0.02mg/L), and other carbohydrates (0.03mg/L). This method was successfully applied to determine GG and sucrose in intracellular extracts of salt-stressed cyanobacteria. PMID:26279008

  12. Characterization of a novel diclofenac metabolite in human urine by capillary gas chromatography-negative chemical ionization mass spectrometry.

    PubMed

    Blum, W; Faigle, J W; Pfaar, U; Sallmann, A

    1996-10-25

    A sensitive analytical method was developed to characterize diclofenac metabolites in small amounts of body fluids. Desalted and lyophilized urine samples were extracted with supercritical carbon dioxide directly or after acidic hydrolysis. The extracts were derivatized with N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamide. The derivatives were separated by capillary gas chromatography and identified by negative chemical ionization mass spectrometry. Full mass spectra were obtained at a level of 1.10(-9) g/ml. With direct extraction, the metabolites could be analysed in one step as open-chained acids and as (cyclic) oxindoles. By acidic hydrolysis the conjugates were transformed to the oxindoles. With both methods, a new main metabolite, [2-[2,6-dichloro-4-hydroxy-3-methoxyphenyl)amino]phenyl]acetic acid, was identified The mechanism of its formation is discussed. PMID:8953166

  13. 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. PMID:20209666

  14. New approach for the detection of BSH and its metabolites using capillary electrophoresis and electrospray ionization mass spectrometry.

    PubMed

    Mauri, Pier Luigi; Basilico, Fabrizio; Pietta, Pier Giorgio; Pasini, Erica; Monti, Diego; Sauerwein, Wolfgang

    2003-05-01

    Boron neutron capture therapy is a promising binary treatment for cancer. It is based on the nuclear fission that occurs when non-radioactive 10B absorbs thermal neutrons. One of the two boron compounds currently used in clinical trials for this therapy is BSH. To ensure differentiated retention in the tumour versus normal tissue prior to treatment, routine analytical methods to determine pharmacokinetics must be available. For this purpose we have developed a new, easy and time saving approach, in which the separation of boron derivatives is performed by means of capillary electrophoresis (CE). The CE method allows analyses to be performed in short times (less than 18 min), sensitively (LOD 8 pg loaded on the capillary) quantitatively (LOQ 5 microg/ml) and with a high efficiency of separation. Moreover it is simpler than HPLC and more reproducible (intra- and inter-day values were +/-1% and +/-3%, respectively), and does not require a specific column of derivatization. Mass spectrometry analysis of boron derivatives in different samples was also performed to ensure correct attribution of the CE peaks. PMID:12668066

  15. 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. PMID:26307710

  16. 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

    2016-02-01

    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. PMID:26784525

  17. 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.

  18. Determination of carboxylic acids in oil samples by capillary gas chromatography/mass spectrometry

    SciTech Connect

    Shen, J.

    1981-03-01

    A combined gas chromatography/mass spectrometric (GC/MS) method for measuring carboxylic acids in oil samples without first going through solvent extraction and group separation is reported. The carboxylic acids in oils are directly derivatized to their corresponding methyl esters via anion formation in tetramethylammonium hydroxide/methanol/methyl iodide/n-butyl acetate solutions prior to GC/MS analysis using a glass wall coated capillary column. The reaction is mild, selective, and rapid. It can usually be carried out at room temperature and completed in 10 to 15 min. Multiple ion detection techniques (MID) can be readily used to further resolve methyl esters from other compounds if necessary.

  19. Evaluation of adsorption preconcentration/capillary zone electrophoresis/nanoelectrospray mass spectrometry for peptide and glycoprotein analyses.

    PubMed

    Bateman, K P; White, R L; Thibault, P

    1998-11-01

    The use of an on-line adsorption preconcentrator coupled with capillary zone electrophoresis/nanoelectrospray mass spectrometry (PC/CZE/nESMS) is described for the analysis of peptides and protein digests. The investigation was focused on the production of disposable preconcentrators made of large particle size (40 microns irregular packing), thereby eliminating the use of a retaining frit without loss of performance. These preconcentration devices were made of commercially available components which can be easily interfaced to current CZE/nESMS systems. Practical issues such as the composition of the stationary phase, the elution volume and sample breakthrough and carry-over were evaluated in order to optimize the analytical performance of this technique. Under optimized elution conditions, the PC/CZE/nESMS technique provided separation efficiencies in excess of 100,000 theoretical plates for a sample loading of 8 microliters. Sample carry-over was minimized by proper reconditioning of the preconcentrator prior to the CZE separation. Alternatively, the sample carry-over resulting from small elution volumes could be used advantageously to provide multiple analyses from a single injection of sample. The application of this technique is demonstrated for the analysis of proteolytic peptides from a Bauhinia purpurea lectin at a concentration level of 30 nM. Further structural information was obtained using on-line tandem mass spectrometry to elucidate the structure of N-linked glycans and the amino acid sequences of the glycopeptides. PMID:9835067

  20. 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

  1. Capillary LC Coupled with High-Mass Measurement Accuracy Mass Spectrometry for Metabolic Profiling

    SciTech Connect

    Ding, Jie; Sorensen, Christina M.; Zhang, Qibin; Jiang, Hongliang; Jaitly, Navdeep; Livesay, Eric A.; Shen, Yufeng; Smith, Richard D.; Metz, Thomas O.

    2007-08-15

    We have developed an efficient and robust high-pressure capillary LC-MS method for the identification of large numbers of metabolites in biological samples using both positive and negative ESI modes. Initial efforts focused on optimizing the separations conditions for metabolite extracts using various LC stationary phases in conjunction with multiple mobile phase systems, as applied to the separation of 45 metabolite standards. The optimal mobile and stationary phases of those tested were determined experimentally (in terms of peak shapes, theoretical plates, retention of small, polar compounds, etc.), and both linear and exponential gradients were applied in the study of metabolite extracts from the cyanobacterium Cyanothece sp. ATCC 51142. Finally, an automated dual-capillary LC system was constructed and evaluated for the effectiveness and reproducibility of the chromatographic separations using the above samples. When coupled with a commercial LTQ-Orbitrap MS, ~900 features were reproducibly detected from Cyanothece sp. ATCC 51142 metabolite extracts. In addition, 12 compounds were tentatively identified, based on accurate mass, isotopic distribution, and MS/MS information.

  2. 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.

  3. Non-aqueous capillary electrophoresis for the analysis of acidic compounds using negative electrospray ionization mass spectrometry.

    PubMed

    Bonvin, Grégoire; Schappler, Julie; Rudaz, Serge

    2014-01-01

    Non-aqueous capillary electrophoresis (NACE) is an attractive CE mode, in which water solvent of the background electrolyte (BGE) is replaced by organic solvent or by a mixture of organic solvents. This substitution alters several parameters, such as the pKa, permittivity, viscosity, zeta potential, and conductivity, resulting in a modification of CE separation performance (i.e., selectivity and/or efficiency). In addition, the use of NACE is particularly well adapted to ESI-MS due to the high volatility of solvents and the low currents that are generated. Organic solvents reduce the number of side electrochemical reactions at the ESI tip, thereby allowing the stabilization of the ESI current and a decrease in background noise. All these features make NACE an interesting alternative to the aqueous capillary zone electrophoresis (CZE) mode, especially in combination with mass spectrometry (MS) detection. The aim of this work was to evaluate the use of NACE coupled to negative ESI-MS for the analysis of acidic compounds with two available CE-MS interfaces (sheath liquid and sheathless). First, NACE was compared to aqueous CZE for the analysis of several pharmaceutical acidic compounds (non-steroidal anti-inflammatory drugs, NSAIDs). Then, the separation performance and the sensitivity achieved by both interfaces were evaluated, as were the impact of the BGE and the sample composition. Finally, analyses of glucuronides in urine samples subjected to a minimal sample pre-treatment ("dilute-and-shoot") were performed by NACE-ESI-MS, and the matrix effect was evaluated. A 20- to 100-fold improvement in sensitivity was achieved using the NACE mode in combination with the sheathless interface and no matrix effect was observed regardless of the interfaces. PMID:24315358

  4. 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. PMID:16736457

  5. Comparative Glycoprofiling of HIV gp120 Immunogens by Capillary Electrophoresis and MALDI Mass Spectrometry

    PubMed Central

    Guttman, Miklós; Váradi, Csaba; Lee, Kelly K.; Guttman, András

    2015-01-01

    The Human Immunodeficiency Virus (HIV) envelope glycoprotein (Env) is the primary antigenic feature on the surface of the virus and is of key importance in HIV vaccinology. Vaccine trials with the gp120 subunit of Env are ongoing with the recent RV144 trial showing moderate efficacy. gp120 is densely covered with N-linked glycans that are thought to help evade the host's humoral immune response. To assess how the global glycosylation patterns vary between gp120 constructs, the glycan profiles of several gp120s were examined by capillary electrophoresis with laser induced fluorescence detection and MALDI-MS. The glycosylation profiles were found to be similar for chronic vs. transmitter/founder isolates and only varied moderately between gp120s from different clades. This study revealed that the addition of specific tags, such as the gD tag used in the RV144 trial, had significant effects on the overall glycosylation patterns. Such effects are likely to influence the immunogenicity of various Env immunogens and should be considered for future vaccine strategies, emphasizing the importance of the glycosylation analysis approach described in this paper. PMID:25809283

  6. [The analysis of caramel colors. 1. Differentiation of classes of caramel coloring agents with Curie-point pyrolysis-capillary gas chromatography-mass spectrometry].

    PubMed

    Hardt, R; Baltes, W

    1987-10-01

    After an introduction on the production, classification, legislative regulations, toxicology, and analysis of caramel colours, a report is given on the examination of these colourings by Curie-point pyrolysis-capillary gas chromatography-mass spectrometry. This method enables the differentiation between the four classes of caramel colours on the basis of the most concentrated of more than 100 identified pyrolysis products, which requires small quantities of substance (100 micrograms) and short periods of time (1 h). PMID:3424998

  7. Determination of arsenic species in Solanum Lyratum Thunb using capillary electrophoresis with inductively coupled plasma mass spectrometry.

    PubMed

    Shuai, Pei-Yu; Yang, Xiao-Jun; Qiu, Zong-Qing; Wu, Xiao-Hui; Zhu, Xi; Pokhrel, Ganga Raj; Fu, Yu-Ying; Ye, Hui-Min; Lin, Wen-Xiong; Yang, Gui-Di

    2016-08-01

    A simple and highly efficient interface to couple capillary electrophoresis with inductively coupled plasma mass spectrometry by a microflow polyfluoroalkoxy nebulizer and a quadruple ion deflector was developed in this study. By using this interface, six arsenic species, including arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, and arsenocholine, were baseline-separated and determined in a single run within 11 min under the optimized separation conditions. The instrumental detection limit was in the range of 0.02-0.06 ng/mL for the six arsenic compounds. Repeatability expressed as the relative standard deviation (n = 5) of both migration time and peak area were better than 2.5 and 4.3% for six arsenic compounds. The proposed method, combined with a closed-vessel microwave-assisted extraction procedure, was successfully applied for the determination of arsenic species in the Solanum Lyratum Thunb samples from Anhui province in China with the relative standard deviations (n = 5) ≤4%, method detection limits of 0.2-0.6 ng As/g and a recovery of 98-104%. The experimental results showed that arsenobetaine was the main speciation of arsenic in the Solanum Lyratum Thunb samples from different provinces in China, with a concentration of 0.42-1.30 μg/g. PMID:27378629

  8. Pressurized liquid extraction-capillary electrophoresis-mass spectrometry for the analysis of polar antioxidants in rosemary extracts.

    PubMed

    Herrero, Miguel; Arráez-Román, David; Segura, Antonio; Kenndler, Ernst; Gius, Beatrice; Raggid, Maria Augusta; Ibáñez, Elena; Cifuentes, Alejandro

    2005-08-19

    A method based on capillary electrophoresis-electrospray-mass spectrometry (CE-ESI-MS) was developed to qualitatively characterize natural antioxidants from rosemary (Rosmarinus officinalis L.) in different fractions obtained by pressurized liquid extraction (PLE) using subcritical water. The parameters of CE-ESI-MS were adjusted allowing the separation and characterization of different compounds from rosemary in the PLE fractions. These parameters for CE are kind, pH and concentration of the separation buffer, parameters for ESI-MS are dry gas temperature and flow, nebulizing gas pressure, and make-up flow. The following analytical conditions were found most favorable: aqueous CE buffer (40 mM ammonium acetate/ammonium hydroxide, pH 9); sheath liquid containing 2-propanol-water (60:40, v/v) and 0.1% (v/v) triethylamine at a flow rate of 0.24 mL/h; drying gas flow rate equal to 7 L/min at 350 degrees C, nebulizing gas pressure of 13.8 kPa (2 psi), using a compound stability of 50%. Different antioxidant compounds (e.g., rosmarinic acid and carnosic acid) could be detected in the rosemary extracts by CE-ESI-MS without any additional treatment, enabling the determination of variations in the extract composition caused by the different PLE conditions (i.e., 60 and 100 degrees C). The results provide complementary information to HPLC analysis. PMID:16114236

  9. Identification of synthetic dyes in early colour photographs using capillary electrophoresis and electrospray ionisation-mass spectrometry.

    PubMed

    López-Montes, Ana Ma; Dupont, Anne-Laurence; Desmazières, Bernard; Lavédrine, Bertrand

    2013-09-30

    Capillary electrophoresis with photodiode array detection (CE-PDA) and with electrospray ionisation-mass spectrometry (CE-ESI-MS) was used for the separation and the identification of 23 synthetic organic dyes, among those used in early 20th century colour photographs such as autochromes. Both cationic and anionic dyes could be separated within 15min using a single CE-PDA method. The method was used as the basis to develop a CE-ESI-MS methodology through the optimisation of the relevant ESI and MS parameters. Sheath liquid composition, nebulising gas pressure, drying gas flow rate and drying gas temperature were found to influence the sensitivity of the detection. These parameters were optimised in positive and negative ion modes for cationic dyes and anionic dyes, respectively. The two analyses could be carried out successively on a single sample. In view of the application to cultural heritage objects, the CE-ESI-MS analytical procedure was applied to identify the dyes in a Filmcolor artefact, late version of the autochrome. The results complemented and enhanced current knowledge as four cationic dyes and three anionic dyes were identified. Four additional dyes are proposed as possibly present as traces. PMID:23953463

  10. A snapshot of plasma metabolites in first-episode schizophrenia: a capillary electrophoresis time-of-flight mass spectrometry study

    PubMed Central

    Koike, S; Bundo, M; Iwamoto, K; Suga, M; Kuwabara, H; Ohashi, Y; Shinoda, K; Takano, Y; Iwashiro, N; Satomura, Y; Nagai, T; Natsubori, T; Tada, M; Yamasue, H; Kasai, K

    2014-01-01

    Few biomarkers have been known that can easily measure clinical conditions in mental illnesses such as schizophrenia. Capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) is a new method that can measure ionized and low-molecular-weight metabolites. To explore global metabolomic alterations that characterize the onset of schizophrenia and identify biomarkers, we profiled the relative and absolute concentrations of the plasma metabolites from 30 patients with first-episode schizophrenia (FESZ, four drug-naïve samples), 38 healthy controls and 15 individuals with autism spectrum disorders using CE-TOFMS. Five metabolites had robust changes (increased creatine and decreased betaine, nonanoic acid, benzoic acid and perillic acid) in two independent sample sets. Altered levels of these metabolites are consistent with well-known hypotheses regarding abnormalities of the homocysteine metabolism, creatine kinase-emia and oxidative stress. Although it should be considered that most patients with FESZ received medication, these metabolites are candidate biomarkers to improve the determination of diagnosis, severity and clinical stages, especially for FESZ. PMID:24713860

  11. New insights in Adipokinetic Hormone (AKH) precursor processing in Locusta migratoria obtained by capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Baggerman, G; Huybrechts, J; Clynen, E; Hens, K; Harthoorn, L; Van der Horst, D; Poulos, C; De Loof, A; Schoofs, L

    2002-04-01

    After translation, the AKH I and AKH II precursors form three dimeric constructs prior to further processing into the respective AKHs and three dimeric Adipokinetic Hormone Precursor Related Peptides or APRPs (two homodimers and one heterodimer). By capillary liquid chromatography-tandem mass spectrometry we demonstrate that the APRPs in Locusta migratoria are further processed to form two smaller neuropeptides: DAADFADPYSFL (residue 36 to 47 of the AKH I precursor) and YADPNADPMAFL (residue 34 to 45 of the AKH II precursor). The peptides are designated as Adipokinetic Hormone Joining Peptide 1 (AKH-JP I) and 2 (AKH-JP II) respectively. Within the AKH I and AKH II precursor molecules, the classic KK and RR processing sites separate the AKH-JPs from the AKH I and II respectively. At the carboxyterminus, both AKH-JP I and II are flanked by Tyr-Arg, a cleaving site not described before. Such an unusual cleavage site suggests the presence, in the corpora cardiaca, of specific convertases. The AKH-JP-II does not stimulate lipid release from the fat body nor does it stimulate glycogen phosphorylase activity, both key functions of AKH. PMID:11897382

  12. Optimization of field-amplified sample injection for analysis of peptides by capillary electrophoresis-mass spectrometry.

    PubMed

    Yang, Yuanzhong; Boysen, Reinhard I; Hearn, Milton T W

    2006-07-15

    A versatile experimental approach is described to achieve very high sensitivity analysis of peptides by capillary electrophoresis-mass spectrometry with sheath flow configuration based on optimization of field-amplified sample injection. Compared to traditional hydrodynamic injection methods, signal enhancement in terms of detection sensitivity of the bioanalytes by more than 3000-fold can be achieved. The effects of injection conditions, composition of the acid and organic solvent in the sample solution, length of the water plug, sample injection time, and voltage on the efficiency of the sample stacking have been systematically investigated, with peptides in the low-nanomolar (10(-9) M) range readily detected under the optimized conditions. Linearity of the established stacking method was found to be excellent over 2 orders of magnitude of concentration. The method was further evaluated for the analysis of low concentration bioactive peptide mixtures and tryptic digests of proteins. A distinguishing feature of the described approach is that it can be employed directly for the analysis of low-abundance protein fragments generated by enzymatic digestion and a reversed-phase-based sample-desalting procedure. Thus, rapid identification of protein fragments as low-abundance analytes can be achieved with this new approach by comparison of the actual tandem mass spectra of selected peptides with the predicted fragmentation patterns using online database searching algorithms. PMID:16841892

  13. 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. PMID:18585986

  14. Confirmation of clorsulon residues in cattle kidney by capillary gas chromatography-negative-ion chemical-ionization mass spectrometry.

    PubMed

    Wehner, T A; Wood, J S; Walker, R; Downing, G V; Vandenheuvel, W J

    1987-07-24

    A confirmatory assay for residues of the anthelmintic agent clorsulon [4-amino-6-(trichloroethenyl)-1,3-benzenedisulfonamide] in cattle kidney tissue has been developed. The assay involves isolation of a drug-containing fraction by solvent extraction, methylation of the analyte, and fused-silica capillary column gas chromatography-negative-ion chemical-ionization mass spectrometry of the pentamethyl derivative of clorsulon. The intensities of four negative ions [m/z 406 and 408 (trichloro species) and m/z 413 and 415 (dichloro species)] are monitored. Confirmation of the presence of drug in an analyte requires that all four ions appear at the appropriate retention time with their intensity ratios within 10-15% of those arising from analysis of the reference standard, methylated clorsulon; the lower limit of detection is 3 ppb. Quantification of the drug is based on the intensity of the m/z 406 ion. Identification and quantification of residues by the gas chromatographic-mass spectrometric assay gave results in good agreement with those obtained with an electron-capture gas chromatographic assay. PMID:3654857

  15. Classification of congenital disorders of glycosylation based on analysis of transferrin glycopeptides by capillary liquid chromatography-mass spectrometry.

    PubMed

    Barroso, Albert; Giménez, Estela; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

    2016-11-01

    In this work, we describe a multivariate data analysis approach for data exploration and classification of the complex and large data sets generated to study the alteration of human transferrin (Tf) N-glycopeptides in patients with congenital disorders of glycosylation (CDG). Tf from healthy individuals and two types of CDG patients (CDG-I and CDG-II) is purified by immunoextraction from serum samples before trypsin digestion and separation by capillary liquid chromatography mass spectrometry (CapLC-MS). Following a targeted data analysis approach, partial least squares discriminant analysis (PLS-DA) is applied to the relative abundance of Tf glycopeptide glycoforms obtained after integration of the extracted ion chromatograms of the different samples. The performance of PLS-DA for classification of the different samples and for providing a novel insight into Tf glycopeptide glycoforms alteration in CDGs is demonstrated. Only six out of fourteen of the detected glycoforms are enough for an accurate classification. This small glycoform set may be considered a sensitive and specific novel biomarker panel for CDGs. PMID:27591658

  16. Measurement of rimantadine in plasma by capillary gas chromatography/mass spectrometry with a deuterium-labeled internal standard

    SciTech Connect

    Herold, D.A.; Anonick, P.K.; Kinter, M.; Hayden, F.G.

    1988-08-01

    Rimantadine is a synthetic antiviral agent used in prophylaxis and in treating the early stages of uncomplicated influenza A illness. We describe a stable isotope-dilution assay involving capillary gas chromatography/mass spectrometry. We used 200 ng of d3-rimantadine, added to 1 mL of plasma, as the internal standard. The rimantadine was extracted from the plasma with a Bond-Elut CN column, the column was washed with water, and the rimantadine was eluted with methanol, dried, and treated to form the t-butyldimethylsilyl derivative. The mass spectrometer was operated in the selected ion monitoring mode. Ions at m/z 236 and m/z 239 were monitored, corresponding to the loss of C4H9 from the rimantadine derivative and d3-rimantadine, respectively. Within-run precision (CVs) ranged from 8.9% at 29 micrograms/L to 3.2% at 1666 micrograms/L. Corresponding data for between-run precision were 5.4% and 1.7%. Treated volunteers (n = 86) provided plasma samples with a concentration range of 153 to 1127 micrograms/L. This simplified method allows rapid, precise assay of rimantadine in plasma.

  17. Energy Charge, Redox State, and Metabolite Turnover in Single Human Hepatocytes Revealed by Capillary Microsampling Mass Spectrometry.

    PubMed

    Zhang, Linwen; Vertes, Akos

    2015-10-20

    Metabolic analysis of single cells to uncover cellular heterogeneity and metabolic noise is limited by the available tools. In this study, we demonstrate the utility of capillary microsampling electrospray ionization mass spectrometry with ion mobility separation for nontargeted analysis of single cells. On the basis of accurate mass measurements and collision cross-section determination, a large number of chemical species, 22 metabolites and 54 lipids, were identified. To assess the cellular response to metabolic modulators, the adenylate energy charge (AEC) levels for control and rotenone treated cells were evaluated. A significant reduction in the AEC values was observed for rotenone treated cells. For the cells under oxidative stress, the mean value for the [reduced glutathione (GSH)]/[oxidized glutathione (GSSG)] ratio was significantly decreased, whereas the distribution of the [uridine diphosphate N-acetylhexosamine (UDP-HexNAc)]/[uridine diphosphate hexose (UDP-hexose)] ratio exhibited dramatic tailing to higher values. Lipid turnover rates were studied by pulse-chase experiments at the single cell level. PMID:26398405

  18. Analysis of pesticides in soy milk combining solid-phase extraction and capillary electrophoresis-mass spectrometry.

    PubMed

    Hernández-Borges, Javier; Rodriguez-Delgado, Miguel Angel; García-Montelongo, Francisco J; Cifuentes, Alejandro

    2005-06-01

    In this work, the determination of a group of triazolopyrimidine sulfoanilide herbicides (cloransulam-methyl, metosulam, flumetsulam, florasulam, and diclosulam) in soy milk by capillary electrophoresis-mass spectrometry (CE-MS) is presented. The main electrospray interface (ESI) parameters (nebulizer pressure, dry gas flow rate, dry gas temperature, and composition of the sheath liquid) are optimized using a central composite design. To increase the sensitivity of the CE-MS method, an off-line sample preconcentration procedure based on solid-phase extraction (SPE) is combined with an on-line stacking procedure (i.e. normal stacking mode, NSM). Samples could be injected for up to 100 s, providing limits of detection (LODs) down to 74 microg/L, i.e., at the low ppb level, with relative standard deviation values (RSD,%) between 3.8% and 6.4% for peak areas on the same day, and between 6.5% and 8.1% on three different days. The usefulness of the optimized SPE-NSM-CE-MS procedure is demonstrated through the sensitive quantification of the selected pesticides in soy milk samples. PMID:16013821

  19. Determination of aminoglycosides in honey by capillary electrophoresis tandem mass spectrometry and extraction with molecularly imprinted polymers.

    PubMed

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

    2015-09-01

    A new analytical method based on capillary zone electrophoresis-tandem mass spectrometry is proposed and validated for the identification and simultaneous quantification of nine aminoglycosides in honey samples. Detection using an ion trap mass analyzer operating in the multiple reaction monitoring mode was used. Different parameters were optimized in order to obtain an adequate separation combined with the highest sensitivity. In order to achieve high selectivity in the sample treatment, a commercially-available molecularly imprinted polymer has been used for the solid phase extraction of the analytes. Under optimum conditions, recoveries for fortified samples ranged from 88.2 to 99.8%, with relative standard deviations lower than 8%. The limits of detection ranged from 0.4 to 28.5 μg kg(-1). Furthermore, the decision limit and the detection capability were evaluated, ranging from 3.5 to 60.5 μg kg(-1) and from 6.0 to 103.1 μg kg(-1), respectively, demonstrating the sensitivity and applicability of this fast and simple method. PMID:26388393

  20. 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.

  1. 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. PMID:14971492

  2. 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

    2015-10-01

    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

  3. 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

  4. Simultaneous separation and determination of organic acids in blueberry juices by capillary electrophoresis- electrospray ionization mass spectrometry.

    PubMed

    Li, Bin; Yongku, Li; Wang, Xinyi; Wang, Fen; Wang, Xu; Wang, Yanfang; Meng, Xianjun

    2015-08-01

    A sensitive and expeditious capillary electrophoresis-electrospray ionization mass spectrometry(CE-ESIMS) method for the separation, identification and determination of succinic, citric, salicylic, malic, benzoic, sorbic, ascorbic, and tartaric acid in blueberry juices has been developed. In order to obtain the analytical separation, CE-MS interface parameters(e.g., buffer pH and composition, sheath liquid and gas flow rates, sheath liquid composition, electrospray voltage, etc.) were carefully optimized. Eight organic acids were baseline separated in 8 min under optimum experimental conditions. The precisions for eight replicate separations of a standard mixture solution were 2.54-4.12 % for peak area and 0.85-2.12 % for migration time respectively. The linear ranges were 10.0-1000.0, 8.0-1000.0, 13.0-1000.0, 6.0-1000.0, 9.0-1000.0, 3.2-600.0, 6.0-1000.0 and 18.0-1000.0 μg/L for succinic, citric, salicylic, malic, benzoic, sorbic, ascorbic, and tartaric acid with detection limits of 2.5, 2.0, 3.4, 1.5, 2.2, 0.8, 1.5, 4.5 μg/L, respectively. The average recoveries of the eight components were between 86.8 and 99.8 % with RSDs of 1.8-5.3 %. The proposed method was applied to the simultaneous analysis of eight analytes in Blueberry Juice samples with satisfactory results. PMID:26243946

  5. 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. PMID:23922762

  6. Analysis of recombinant human erythropoietin glycopeptides by capillary electrophoresis electrospray-time of flight-mass spectrometry.

    PubMed

    Giménez, Estela; Ramos-Hernan, Raquel; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

    2012-01-01

    Capillary electrophoresis electrospray-mass spectrometry was used to detect and characterize the great variety of O- and N-glycopeptide glycoforms of recombinant human erythropoietin (rhEPO) using an orthogonal accelerating time-of-flight mass spectrometer to obtain their exact molecular masses (CE-TOF-MS). rhEPO was digested with trypsin and Glu-C and analyzed by CE-TOF-MS to detect O(126), N(83), N(24)-N(38) and N(24) and N(38) glycopeptide glycoforms, respectively. Neuraminidase was first used to enhance the detection of the glycopeptides and detect all possible glycoforms contained in each glycosylation site. O(126) and N(83) glycopeptides were extensively characterized. Twelve sialoforms corresponding to 5 different glycoforms were detected in N(83), and for the first time, a sulfated sialoform of this glycopeptide was also detected. In the case of O(126), different sialoforms with different types of sialic acids (Neu5Gc and Neu5Ac) were detected and an estimation of the relative percentage of Neu5Gc versus Neu5Ac was also carried out for this glycopeptide. N(24) and N(38) glycosylation sites were also characterized by CE-TOF-MS after Glu-C digestion and these results permitted to rule out some glycan combinations for N(24)-N(38) glycopeptide glycoforms. This study provided a reliable glycopeptide map of rhEPO and may be regarded as an excellent starting point to analyze rhEPO glycopeptides in biological fluids and detect the use of this hormone in sports. PMID:22122935

  7. 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

    2004-10-01

    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. PMID:15532584

  8. 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. PMID:17222002

  9. Determination of steroids and their intact glucuronide conjugates in mouse brain by capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Jäntti, Sirkku E; Tammimäki, Anne; Raattamaa, Helena; Piepponen, Petteri; Kostiainen, Risto; Ketola, Raimo A

    2010-04-15

    A method for the identification and quantitation of 10 brain steroids and their 2 sulfate and 9 glucuronide conjugates in mouse brain tissues was developed and validated. The method includes the extraction of homogenized brain by solid-phase extraction and the analysis of the extracts by capillary liquid chromatography-tandem mass spectrometry. The main advantage of the method is that steroid conjugates in brain can be analyzed as intact compounds, without derivatization, hydrolysis, or complex sample preparation procedures; thus, the true identity of the conjugates can be confirmed with tandem mass spectrometric detection. The method was validated to show its linearity (r > 0.998) and precision (<9%). The limits of detection in solution were from 6 to 80 pmol/L for steroid glucuronides, from 13 to 32 pmol/L for steroid sulfates, and from 26 pmol/L to 2.2 nmol/L for native steroids. The recovery of internal standards was 95% for d3-testosterone glucuronide and 69% for d4-allopregnanolone from spiked mouse hippocampus. Brain tissue samples from mouse hippocampus and hypothalamus were analyzed using the new method. Several steroids and glucuronides were identified and quantified from the mouse brain at concentration levels of 0.2-58 ng/g. The concentrations of steroid glucuronides were significant compared to those of their aglycons, indicating that glucuronidation might be an important metabolic pathway for some steroids in the mouse brain. The method developed in this study provides for the first time direct quantitative determination of steroids and their glucuronides and sulfates in brain without hydrolysis and, therefore, creates the possibility to study in detail the role of steroid glucuronidation and sulfation in the brain. PMID:20345173

  10. A quick method for determination of psychoactive agents in serum and hair by using capillary electrophoresis and mass spectrometry.

    PubMed

    Woźniakiewicz, Aneta; Wietecha-Posłuszny, Renata; Woźniakiewicz, Michał; Bryczek, Ewelina; Kościelniak, Paweł

    2015-01-01

    The aim of the research was to develop a new sensitive method for simultaneously the determination of psychoactive drugs: 1-benzylpiperazine, 7-aminoclonazepam, alprazolam, clonazepam, diazepam, estazolam, lorazepam and tetrazepam in human serum and hair samples. In the preparation step, microwave-assisted extraction (MAE) was used. Extracts were analyzed by means of capillary electrophoresis with mass spectrometry time-of-flight detection (CE-TOF-MS). In the validation study of the MAE/CE-TOF-MS analytical method, three concentration levels of analytes (10, 100 and 250 ng/mL for serum and 0.2, 2.2 and 5.6 ng/mL for hair) were taken into account. Such parameters as limit of detection (0.4-1.2 ng/mL for serum, 6.0-23.0 pg/mg for hair), limit of quantification (1.3-4.1 ng/mL for serum, 20.0-77.0 pg/mg for hair), precision (3.0-11.3% for serum, 2.4-14.2% for hair), accuracy of the assay (RE) (-8.0 to 12.0% for serum, -8.0 to 11.0% for hair), recovery (88.6-113.4% for serum, 86.1-107.4% for hair) and matrix effects (87.9-110.7% for serum, 85.1-108.4% for hair) were calculated for the studied compounds. Then, the MAE/CE-TOF-MS method was successfully applied to the analysis of hair samples taken from patients treated with benzodiazepines. PMID:25890213

  11. 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

  12. Rapid discovery of putative protein biomarkers of traumatic brain injury by SDS-PAGE-capillary liquid chromatography-tandem mass spectrometry.

    PubMed

    Haskins, William E; Kobeissy, Firas H; Wolper, Regina A; Ottens, Andrew K; Kitlen, Jason W; McClung, Scott H; O'Steen, Barbara E; Chow, Marjorie M; Pineda, Jose A; Denslow, Nancy D; Hayes, Ronald L; Wang, Kevin K W

    2005-06-01

    We report the rapid discovery of putative protein biomarkers of traumatic brain injury (TBI) by SDS-PAGE-capillary liquid chromatography-tandem mass spectrometry (SDS-PAGE-Capillary LC-MS(2)). Ipsilateral hippocampus (IH) samples were collected from naive rats and rats subjected to controlled cortical impact (a rodent model of TBI). Protein database searching with 15,558 uninterpreted MS(2) spectra, collected in 3 days via data-dependent capillary LC-MS(2) of pooled cyanine dye-labeled samples separated by SDS-PAGE, identified more than 306 unique proteins. Differential proteomic analysis revealed differences in protein sequence coverage for 170 mammalian proteins (57 in naive only, 74 in injured only, and 39 of 64 in both), suggesting these are putative biomarkers of TBI. Confidence in our results was obtained by the presence of several known biomarkers of TBI (including alphaII-spectrin, brain creatine kinase, and neuron-specific enolase) in our data set. These results show that SDS-PAGE prior to in vitro proteolysis and capillary LC-MS(2) is a promising strategy for the rapid discovery of putative protein biomarkers associated with a specific physiological state (i.e., TBI) without a priori knowledge of the molecules involved. PMID:15941373

  13. 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

  14. Analysis of phosphorus-containing amino acid-type herbicides by sheathless capillary electrophoresis/electrospray ionization-mass spectrometry using a high sensitivity porous sprayer.

    PubMed

    Kawai, Mio; Iwamuro, Yoshiaki; Iio-Ishimaru, Reiko; Chinaka, Satoshi; Takayama, Nariaki; Hayakawa, Kazuichi

    2011-01-01

    We describe a new practical capillary electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS) method for the forensic analysis of phosphorus-containing amino acid-type herbicides, glyphosate (GLYP), glufosinate (GLUF) and bialaphos (BIAL). A new sheathless interface, a high sensitivity porous sprayer (HSPS), was used in this study. The limits of detections of GLYP, GLUF and BIAL were 7.6, 0.61 and 0.57 pg, respectively. These values were 4-36 times lower than these obtained by conventional CE/ESI-MS using a sheath liquid. The developed method was successfully applied to the analysis of beverages spiked with the herbicides. PMID:21828926

  15. Use of capillary electrophoresis with laser-induced fluorescence detection to screen and liquid chromatography-tandem mass spectrometry to confirm sulfonamide residues: validation according to European Union 2002/657/EC.

    PubMed

    Hoff, Rodrigo Barcellos; Barreto, Fabiano; Kist, Tarso B Ledur

    2009-11-13

    A multiresidue method is described for determining six sulfonamides (SAs) (sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxazole, sulfaquinoxaline and sulfadimethoxine) in liver by a capillary electrophoresis screening method and a liquid chromatography coupled to tandem mass spectrometry confirmatory assay. Samples were prepared by homogenizing the tissue, with sodium hydroxide and acetonitrile. After evaporation, extracts were injected in the capillary electrophoresis system or mass spectrometry system for confirmatory analysis. The detection of analytes was achieved by laser-induced fluorescence in capillary electrophoresis. Procedures were validated according to the European Union regulation 2002/657/EC determining specificity, selectivity and detection capability for screening method and decision limit, detection capability, specificity, selectivity, trueness and precision for confirmation method. The results of validation process demonstrate that the method is suitable for application in Brazilian statutory veterinary drug residue surveillance programs. Capillary electrophoresis was proved to be a fast, robust method with low time and reagents consumption. PMID:19765714

  16. Capillary pressure spectrometry: Toward a new method for the measurement of the fractional wettability of porous media

    NASA Astrophysics Data System (ADS)

    Sygouni, Varvara; Tsakiroglou, Christos D.; Payatakes, Alkiviades C.

    2006-05-01

    A transparent porous medium of controlled fractional wettability is fabricated by mixing intermediate-wet glass microspheres with strongly oil-wet polytetrafluouroethylene microspheres, and packing them between two transparent glass plates. Silicon oil is displaced by water, the growth pattern is video-recorded, and the transient response of the pressure drop across the pore network is measured for various fractions of oil-wet particles. The measured global capillary pressure fluctuates as the result of the variation of the equilibrium curvature of menisci between local maxima and local minima. With the aid of wavelets, the transient response of the capillary pressure is transformed to a capillary pressure spectrum (CPS). The peaks of the CPS are used to identify the most significant flow events and correlate their amplitude with the spatial distribution of fractional wettability. The flow events are closely related with the fluctuations of the capillary pressure and are classified into three main categories: motion in pore clusters, generation/expansion of capillary fingers, coalescence of interfaces. The amplitude of the peaks of CPS is related quasilinearly with a local coefficient of fractional wettability presuming that the same class of flow events is concerned. Approximate calculations of the maximum meniscus curvature in pores of converging-diverging geometry and uniform wettability in combination with simple mixing laws predict satisfactorily the experimentally measured average prebreakthrough capillary pressure as a function of the fraction of the oil-wet particles.

  17. Identification of fentanyl derivatives at trace levels with nonaqueous capillary electrophoresis-electrospray-tandem mass spectrometry (MS(n), n = 2, 3): analytical method and forensic applications.

    PubMed

    Rittgen, Jan; Pütz, Michael; Zimmermann, Ralf

    2012-06-01

    The identification of fentanyl derivatives at trace levels employing capillary electrophoresis coupled to electrospray ionization tandem mass spectrometry (CE-ESI-MS(n) , n = 2, 3) is presented. The studied synthetic opioid fentanyl and its derivatives have an exceeding analgesic potency which can be up to 8000 times higher that of morphine. Apart from their therapeutical applications, there is an abuse of them in the drug scene as a heroin substitute. The identification of these opioids at trace levels is of further significant forensic interest with respect to recent seizures of clandestine fentanyl laboratories in Germany. In this work, a nonaqueous capillary electrophoresis (NACE)-ESI-MS(n) procedure was developed for the separation and identification of six fentanyl derivatives including fentanyl, cis- and trans-methylfentanyl, sufentanil, alfentanil, and carfentanil. Their fragmentation pattern in MS(n) experiments were investigated as well as the influence of the sheath-liquid mixture and the influence of the inside diameter of the fused silica capillary on the peak shape and the signal to noise ratio. Method validation included determination of the detection limits (about 1-2 nmol/L) and the repeatability of migration time (at most 0.07% relative standard deviation). The NACE-MS procedure was successfully applied for the analysis of real samples from seizures in illegal fentanyl laboratories. PMID:22736362

  18. 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. PMID:18095054

  19. 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. PMID:24054601

  20. 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 ( ...

  1. In-Line Separation by Capillary Electrophoresis Prior to Analysis by Top-Down Mass Spectrometry Enables Sensitive Characterization of Protein Complexes

    PubMed Central

    2015-01-01

    Intact protein analysis via top-down mass spectrometry (MS) provides a bird’s eye view over the protein complexes and complex protein mixtures with the unique capability of characterizing protein variants, splice isoforms, and combinatorial post-translational modifications (PTMs). Here we applied capillary electrophoresis (CE) through a sheathless CE–electrospray ionization interface coupled to an LTQ Velos Orbitrap Elite mass spectrometer to analyze the Dam1 complex from Saccharomyces cerevisiae. We achieved a 100-fold increase in sensitivity compared to a reversed-phase liquid chromatography coupled MS analysis of recombinant Dam1 complex with a total loading of 2.5 ng (12 amol). N-terminal processing forms of individual subunits of the Dam1 complex were observed as well as their phosphorylation stoichiometry upon Mps1p kinase treatment. PMID:25382489

  2. Characterization of polar polycyclic aromatic compounds in a heavy-duty diesel exhaust particulate by capillary column gas chromatography and high-resolution mass spectrometry

    SciTech Connect

    Bayona, J.M.; Markides, K.E.; Lee, M.L.

    1988-12-01

    Polar normal-phase HPLC fractions of a heavy-duty diesel exhaust particulate, a National Bureau of Standards (NBS) standard reference material (SRM) 1650, were analyzed by capillary column GC coupled to both low- and high-resolution mass spectrometry (HRMS) using electron impact (EI) and negative ion chemical ionization (NICI). Over 80 polycyclic aromatic compounds (PAC), belonging to many different chemical classes (anhydrides, carboxaldehydes, diazaarenes, cyclic imides, nitrohydroxy-PAC, nitroaza-PAC, nitrodiaza-PAC, nitrolactones, and quinones) were tentatively identified. Ten of them were positively identified by comparison of retention times with authentic standards. Among them, phenazine and phthalic anhydride were positively identified for the first time in diesel exhaust particulates. In addition, cyclic imides and their alkylated derivatives were tentatively identified for the first time. Other novel polar chemical classes of PAC were evidenced by MICI MS using a direct-insertion probe.

  3. 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

    2016-08-01

    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. PMID:26879424

  4. 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.

  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. PMID:24630980

  6. 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

    2016-01-01

    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. PMID:26296988

  7. 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

    2015-01-01

    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. PMID:25427190

  8. 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. PMID:26377388

  9. Profiling of Arabidopsis Secondary Metabolites by Capillary Liquid Chromatography Coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry1

    PubMed Central

    von Roepenack-Lahaye, Edda; Degenkolb, Thomas; Zerjeski, Michael; Franz, Mathias; Roth, Udo; Wessjohann, Ludger; Schmidt, Jürgen; Scheel, Dierk; Clemens, Stephan

    2004-01-01

    Large-scale metabolic profiling is expected to develop into an integral part of functional genomics and systems biology. The metabolome of a cell or an organism is chemically highly complex. Therefore, comprehensive biochemical phenotyping requires a multitude of analytical techniques. Here, we describe a profiling approach that combines separation by capillary liquid chromatography with the high resolution, high sensitivity, and high mass accuracy of quadrupole time-of-flight mass spectrometry. About 2,000 different mass signals can be detected in extracts of Arabidopsis roots and leaves. Many of these originate from Arabidopsis secondary metabolites. Detection based on retention times and exact masses is robust and reproducible. The dynamic range is sufficient for the quantification of metabolites. Assessment of the reproducibility of the analysis showed that biological variability exceeds technical variability. Tools were optimized or established for the automatic data deconvolution and data processing. Subtle differences between samples can be detected as tested with the chalcone synthase deficient tt4 mutant. The accuracy of time-of-flight mass analysis allows to calculate elemental compositions and to tentatively identify metabolites. In-source fragmentation and tandem mass spectrometry can be used to gain structural information. This approach has the potential to significantly contribute to establishing the metabolome of Arabidopsis and other model systems. The principles of separation and mass analysis of this technique, together with its sensitivity and resolving power, greatly expand the range of metabolic profiling. PMID:14966245

  10. Styrene oxide DNA adducts: in vitro reaction and sensitive detection of modified oligonucleotides using capillary zone electrophoresis interfaced to electrospray mass spectrometry.

    PubMed

    Schrader, W; Linscheid, M

    1997-01-01

    Styrene is one of the most important synthetic chemicals in the world and is subject to investigations concerning carcinogenicity and mutagenicity due to the active metabolite, styrene-7,8-oxide. This epoxide shows a tendency to react, among others, with DNA and DNA constituents. The in vitro reaction of styrene oxide with DNA was investigated by cleaving incubated calf thymus DNA with two different enzymes, namely Benzonase and alkaline phosphatase, to obtain oligonucleotides of the type n-nucleotide-(n-1)-phosphate with chain length from 2 to 8 bases. Alkylated and nonalkylated nucleotides were separated in groups according to their chain length using capillary zone electrophoresis and were detected with electrospray mass spectrometry. This improvement in sensitivity made it possible to obtain new information about the reaction of styrene oxide with DNA, especially to detect unknown reaction products. The results indicate that primarily purine bases were alkylated by styrene oxide before pyrimidine bases, which react with higher concentrations of styrene oxide. This means that in addition to the already reported adducts in DNA at the N-7-, O6- and N2-position of guanine also adducts at the nucleophilic sites of adenine can be found using mass spectrometry. We anticipate for the future this procedure will allow us to investigate base sequence specific reactions as well as interactions from xenobiotics and cytostatic drugs, since reaction products would directly be detectable. PMID:9285042

  11. Newborn screening of inborn errors of metabolism by capillary electrophoresis-electrospray ionization-mass spectrometry: a second-tier method with improved specificity and sensitivity.

    PubMed

    Chalcraft, Kenneth R; Britz-McKibbin, Philip

    2009-01-01

    The advent of electrospray-ionization mass spectrometry (ESI-MS) has given rise to expanded newborn screening programs for the early detection of inborn errors of metabolism (IEM). Despite the benefit of high-throughput screening for disease prognosis, conventional ESI-MS methods are limited by inadequate specificity, complicated sample handling, and low positive predictive outcome that can contribute to a high rate of false-positives. Herein, we report a robust strategy for neonatal screening based on capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) that offers a convenient platform for the direct analysis of amino acids, acylcarnitines, and their stereoisomers from dried blood spot (DBS) extracts without chemical derivatization. On-line sample preconcentration with desalting by CE-ESI-MS allowed for improved concentration sensitivity when detecting poorly responsive metabolites in complex biological samples without ionization suppression or isomeric/isobaric interferences. Method validation demonstrated that accurate yet precise quantification can be achieved for 20 different amino acid and acylcarnitine biomarkers associated with IEMs when using a single non-deuterated internal standard. CE-ESI-MS represents a promising second-tier method in newborn screening programs that is compatible with ESI-MS/MS technology in cases when improved specificity and sensitivity is warranted for diagnosis confirmation and subsequent monitoring. PMID:19117458

  12. 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%. PMID:25124225

  13. 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. PMID:27027468

  14. 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. PMID:23255368

  15. DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN SOILS USING EQUILIBRIUM HEADSPACE ANALYSIS AND CAPILLARY COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY

    EPA Science Inventory

    Existing methods for determination of volatile organic compounds (VOCs) in soil matrices using the purge and trap technique with gas chromatography/mass spectrometry (GC/MS) have several problems, which include preserving sample integrity from collection to analysis and efficient...

  16. Capillary electrophoresis

    SciTech Connect

    Warner, M.

    1988-10-15

    Rapid instrumental methods for performing electrophoretic separations in capillary tubes have recently been developed, making capillary electrophoresis one of the most exciting new techniques available to analytical chemists. This article discusses detection methods, applications, and the future of capillary electrophoresis.

  17. 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 ...

  18. 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. PMID:26626777

  19. 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. PMID:3379116

  20. 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

  1. Development of a low-flow multiplexed interface for capillary electrophoresis/electrospray ion trap mass spectrometry using sequential spray.

    PubMed

    Chen, Chao-Jung; Li, Fu-An; Her, Guor-Rong

    2008-05-01

    A multiplexed CE-MS interface using four low-flow sheath liquid ESI sprayers has been developed. Because of the limited space between the low-flow sprayers and the entrance aperture of the ESI source, multichannel analysis is difficult using conventional rotating plate approaches. Instead, a multiplexed low-flow system was achieved by applying an ESI potential sequentially to the four low-flow sprayers, resulting in only one sprayer being sprayed at any given time. The synchronization of the scan event and the voltage relays was accomplished by using the data acquisition signal from the IT mass spectrometer. This synchronization resulted in the ESI voltage being sequentially applied to each of the four sprayers according to the corresponding scan event. With this design, a four-fold increase in analytical throughput was achieved. Because of the use of low-flow interfaces, this multiplexed system has superior sensitivity than a rotating plate design using conventional sheath liquid interfaces. The multiplexed design presented has the potential to be applied to other low-flow multiplexed systems, such as multiplexed capillary LC and multiplexed CEC. PMID:18409161

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

    Wunschel, David; Wahl, Jon; Willse, Alan; Valentine, Nancy; Wahl, Karen

    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 spore phenotype. 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. PMID:16798120

  4. Dopant Enriched Nitrogen Gas Combined with Sheathless Capillary Electrophoresis-Electrospray Ionization-Mass Spectrometry for Improved Sensitivity and Repeatability in Glycopeptide Analysis.

    PubMed

    Kammeijer, Guinevere S M; Kohler, Isabelle; Jansen, Bas C; Hensbergen, Paul J; Mayboroda, Oleg A; Falck, David; Wuhrer, Manfred

    2016-06-01

    Over the last years, numerous strategies have been proposed to enhance both ionization efficiency and spray stability in electrospray ionization (ESI), in particular for nanospray applications. In nano-liquid chromatography-mass spectrometry (nano-LC-ESI-MS), a better ESI performance has been observed when a coaxial gas flow is added around the ESI emitter. Moreover, enrichment of the gas with an organic dopant has led to an improved desolvation and ionization efficiency with an overall enhanced sensitivity. In this study, the use of a dopant enriched nitrogen (DEN)-gas combined with sheathless capillary electrophoresis (CE)-ESI-MS was evaluated for glycopeptide analysis. Using acetonitrile as a dopant, an increased sensitivity was observed compared to conventional sheathless CE-ESI-MS. Up to 25-fold higher sensitivities for model glycopeptides were obtained, allowing for limits of detection unachieved by state-of-the-art nano-LC-ESI-MS. The effect of DEN-gas on the repeatability and intermediate precision was also investigated. When compared to previously reported nano-LC-ESI-MS measurements, similar values were found for CE-ESI-MS with DEN-gas. The enhanced repeatability fosters the use of DEN-gas sheathless CE-ESI-MS in protein glycosylation analysis, where precision is essential. The use of DEN-gas opens new avenues for highly sensitive sheathless CE-ESI-MS approaches in glycoproteomics research, by significantly improving sensitivity and precision. PMID:27119460

  5. A novel positively charged achiral co-monomer for β-cyclodextrin monolithic stationary phase: Improved chiral separation of acidic compounds using capillary electrochromatography coupled to mass spectrometry

    PubMed Central

    Bragg, William; Shamsi, Shahab A.

    2013-01-01

    The work presented here demonstrates the incorporation of vinylbenzyl trimethylammonium (VBTA) as a novel positively charged achiral co-monomer to a glycidyl methacrylate-beta cyclodextrin (GMA/β-CD) based monolith, providing anion exchange sites with reversed electroosmotic flow (EOF) for capillary electrochromatography (CEC). The monolithic phases, GMA/β-CD-VBTA and GMA/β-CD (without co-monomer) were characterized by scanning electron microscopy, optical microscopy, pressure drop/flow-rate curves and nitrogen adsorption analysis. After optimizing the stationary phase and mobile phase parameters, chiral separations of 41 pairs of structurally diverse anionic chiral analytes were compared individually using the GMA/β-CD-VBTA and GMA/β-CD monolithic columns. The GMA/β-CD-VBTA monolith chiral stationary phase separated significantly more acidic compounds compared to the GMA/β-CD column. To-date there has been limited work in the development of chiral monolithic column for CEC-mass spectrometry (MS). Because of good electrodriven flow characteristics, which allow the column to maintain a stable current in the absence of outlet vial, GMA/β-CD-VBTA column was successfully coupled to single quadrupole mass spectrometer for CEC-MS of several chiral test compounds. In addition, the same monolithic CEC column when coupled to a triple quadrupole MS instrument, two orders of magnitude higher sensitivity was observed compared to a single quadrupole MS instrument. PMID:23062876

  6. Design, synthesis, and characterization of new cyclic d,l-α-alternate amino acid peptides by capillary electrophoresis coupled to electrospray ionization mass spectrometry.

    PubMed

    Cortez-Díaz, María Dámaris; d'Orlyé, Fanny; Gutierrez-Granados, Silvia; de Leon-Rodriguez, Luis Manuel; Varenne, Anne

    2016-06-01

    The self-assembly of peptide nanotubes (PNTs) depends on the structure and chemistry of cyclic peptide (CP) monomers, having an impact on their properties, making the choice of their monomers and their characterization a great challenge. We synthesized for the first time a new set of eight original CP sequences of 8, 10, and 12 d,l-α-alternate amino acids with a controlled internal diameter from 7 to 13 Å. They present various properties (e.g., diameter, global surface charge, hydrophobicity) that can open the way to new applications. Their structure and purity were determined thanks to a capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) methodology developed for the first time for this purpose. The CPs were successfully separated in a basic hydro-organic background electrolyte (BGE, pH 8.0, H2O/EtOH 50:50, v/v) and analyzed in MS positive mode. The effect of CP structure on electrophoretic mobility was studied, and the mass spectra were deeply analyzed. This methodology allowed verifying their purity and the absence of linear peptide precursors as well as their stability when stored over several months. Therefore, we have developed a new CE-ESI-MS methodology for the structure and purity control of interesting potential precursors for PNTs that could be employed as nanoplatforms in diagnostics or as pseudo sieving tools for separative purposes. PMID:26969790

  7. Chemical vapor deposition of aminopropyl silanes in microfluidic channels for highly efficient microchip capillary electrophoresis-electrospray ionization-mass spectrometry.

    PubMed

    Batz, Nicholas G; Mellors, J Scott; Alarie, Jean Pierre; Ramsey, J Michael

    2014-04-01

    We describe a chemical vapor deposition (CVD) method for the surface modification of glass microfluidic devices designed to perform electrophoretic separations of cationic species. The microfluidic channel surfaces were modified using aminopropyl silane reagents. Coating homogeneity was inferred by precise measurement of the separation efficiency and electroosmotic mobility for multiple microfluidic devices. Devices coated with (3-aminopropyl)di-isopropylethoxysilane (APDIPES) yielded near diffusion-limited separations and exhibited little change in electroosmotic mobility between pH 2.8 and pH 7.5. We further evaluated the temporal stability of both APDIPES and (3-aminopropyl)triethoxysilane (APTES) coatings when stored for a total of 1 week under vacuum at 4 °C or filled with pH 2.8 background electrolyte at room temperature. Measurements of electroosmotic flow (EOF) and separation efficiency during this time confirmed that both coatings were stable under both conditions. Microfluidic devices with a 23 cm long, serpentine electrophoretic separation channel and integrated nanoelectrospray ionization emitter were CVD coated with APDIPES and used for capillary electrophoresis (CE)-electrospray ionization (ESI)-mass spectrometry (MS) of peptides and proteins. Peptide separations were fast and highly efficient, yielding theoretical plate counts over 600,000 and a peak capacity of 64 in less than 90 s. Intact protein separations using these devices yielded Gaussian peak profiles with separation efficiencies between 100,000 and 400,000 theoretical plates. PMID:24655020

  8. 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. PMID:26685060

  9. 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.

  10. 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

  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. Disequilibrium effects in metal speciation by capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS); theory, simulations and experiments.

    PubMed

    Sonke, Jeroen E; Salters, Vincent J M

    2004-08-01

    A theoretical-experimental approach to evaluate disequilibrium effects in capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS) is presented. Electrophoresis requires metal ligand (ML) complexes to be stable on the time scale of separation and detection. By expressing ML complex stability in terms of half-life during a CE separation, an evaluation of separation artifacts can be made. Kinetically slow metals like Cr, Al or Fe form complexes that are stable on the time scale of electrophoretic separations. Kinetically fast metals, like Pb, Hg, Cu, Cd and REE, however tend to form labile complexes which unless complexed by strong chelators will dissociate during CE separations. A reactive transport simulation model of CE separations involving ML complexes allows a more detailed prediction of disequilibrium bias and identifies kinetically limited from mobility-limited types of dissociation. Complementary experimental results are given for kinetic and equilibrium binding experiments of Sm with humic acid. The equilibrium logK for Sm-Leonardite humic acid (HA) binding at pH 7 and 0.01 mol L(-1) ionic strength was determined to be 13.04. Kinetic rates of formation and dissociation for SmHA were 5.9 10(8) and 5.3 10(-5) mol s(-1). PMID:15284917

  13. 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

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

    PubMed

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

    2016-01-15

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

  15. Over 10,000 peptide identifications from the HeLa proteome by using single-shot capillary zone electrophoresis combined with tandem mass spectrometry.

    PubMed

    Sun, Liangliang; Hebert, Alexander S; Yan, Xiaojing; Zhao, Yimeng; Westphall, Michael S; Rush, Matthew J P; Zhu, Guijie; Champion, Matthew M; Coon, Joshua J; Dovichi, Norman J

    2014-12-01

    Capillary zone electrophoresis (CZE)-tandem mass spectrometry (MS/MS) has recently attracted attention as a tool for shotgun proteomics. However, its performance for this analysis has so far fallen far below that of reversed-phase liquid chromatography (RPLC)-MS/MS. The use of a CZE method with a wide separation window (up to 90 min) and high peak capacity (ca. 300) is reported. This method was coupled to an Orbitrap Fusion mass spectrometer through an electrokinetically pumped sheath-flow interface for the analysis of complex proteome digests. Single-shot CZE-MS/MS lead to the identification of over 10 000 peptides and 2100 proteins from a HeLa cell proteome digest in approximately 100 min. This performance is nearly an order of magnitude better than earlier CZE studies and is within a factor of two to four of the state-of-the-art nano ultrahigh-pressure LC system. PMID:25346227

  16. 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.

  17. Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) for the enantiomeric analysis of D,L-selenomethionine in food supplements and urine.

    PubMed

    Devos, Christophe; Sandra, Koen; Sandra, Pat

    2002-01-15

    Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) was applied to the determination of D- and L-selenomethionine in food supplements and in urine. Derivatization was performed with ethylchloroformate (ECF) offering the advantage that the reaction can be carried out in aqueous medium i.e. urine. The derivatives were separated on the chiral stationary phase (CSP) Chiralsil-L-Val. The method was validated with D- and L-seleno-ethionine as internal standard (IS) and the linearity for a seven point calibration from 12.5 pg to 2.5 ng per enantiomer was excellent (R(2) 0.9997). Repeatability of injection (n=3) was <1.8%. The limit of detection (LOD) and quantification (LOQ) were 4 and 12 pg, respectively. Food supplements presently on the market contain L-selenomethionine for at least 90%. Repeatability of the whole procedure (n=6) was tested on one L-selenomethionine formulation and was 3.8 (R.S.D.%). Data for urine samples after a daily intake of L-selenomethionine or the racemate D,L-selenomethionine corresponding to 100 microg selenium indicate that the D-enantiomer is not metabolized. PMID:11755752

  18. Use of capillary gas chromatography with negative ion-chemical ionization mass spectrometry for the determination of perfluorocarbon tracers in the atmosphere.

    PubMed

    Cooke, K M; Simmonds TPG; Nickless, G; Makepeace, A P

    2001-09-01

    A sensitive and selective technique for the quantitative measurement of atmospheric perfluorocarbon trace species at the sub part per quadrillion (10(-15)) levels is presented. The method utilizes advances in adsorbent enrichment techniques coupled with benchtop capillary gas chromatography and negative ion-chemical ionization mass spectrometry. The development and enhancement of sampling technology for tracer experiments is described, and the results from background measurements and a preliminary field experiment are presented. The overall precision of the analytical method with respect to the preferred tracer for these atmospheric transport studies, perfluoromethylcyclohexane, was +/-1.7%. The background concentrations of perfluorodimethylcyclobutane, perfluoromethylcyclopentane, and perfluoromethylcyclohexane at a remote coastal location (Mace Head, Ireland, 53 degrees N, 10 degrees W) were found to be 2.5 (+/-0.4), 6.8 (+/-1.0), and 5.2 fL L(-1) (+/-1.3), respectively. Background concentrations within an urban conurbation (Bristol, U.K.) were slightly greater at 3.0 (+/-1.5), 8.1 (+/-1.8), and 6.3 fL L(-1) (+/-1.1), respectively. PMID:11569822

  19. On-line capillary electrophoresis/microelectrospray ionization-tandem mass spectrometry using an ion trap storage/time-of-flight mass spectrometer with SWIFT technology.

    PubMed

    Jin, X; Kim, J; Parus, S; Lubman, D M; Zand, R

    1999-08-15

    The development of a system capable of the speed required for on-line capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) of tryptic digests is described. The ion trap storage/reflectron time-of-flight (IT/reTOF) mass spectrometer is used as a nonscanning detector for rapid CE separation, where the peptides are ionized on-line using electrospray ionization (ESI). The ESI produced ions are stored in the ion trap and dc pulse injected into the reTOF-MS at a rate sufficient to maintain the separation achieved by CE. Using methodology generated by software and hardware developed in our lab, we can produce SWIFT (Stored Waveform Inverse Fourier Transform) ion isolation and TICKLE activation/fragmentation voltage waveforms to generate MS/MS at a rate as high as 10 Hz so that the MS/MS spectra can be optimized on even a 1-2 s eluting peak. In CE separations performed on tryptic digests of dogfish myelin basic protein (MBP) where eluting peaks 4-8 s wide are observed, it is demonstrated that an acquisition rate of 4 Hz provides > 20 spectra/peak and is more than sufficient to provide optimized MS/MS spectra of each of the eluting peaks in the electropherogram. The detailed structural analysis of dogfish MBP including several posttranslational modifications using CE-MS and CE-MS/MS is demonstrated using this method with < 10 fmol of material consumed. PMID:10464485

  20. 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.

  1. Multiresidue determination of penicillins in environmental waters and chicken muscle samples by means of capillary electrophoresis-tandem mass spectrometry.

    PubMed

    Bailón-Pérez, M Isabel; García-Campaña, Ana M; del Olmo Iruela, Monsalud; Cruces-Blanco, Carmen; Gámiz Gracia, Laura

    2009-05-01

    A new analytical method based on CZE coupled with tandem MS detection (CE-MS/MS) has been developed for the simultaneous determination of nine penicillins of human and veterinary use (nafcillin, dicloxacillin, cloxacillin, oxacillin, ampicillin, penicillin G, amoxicillin, penicillin V and piperacillin), whose levels are regulated by the EU Council regulation No. 2377/90 in animal edible tissues. CE separation conditions, sheath liquid composition and electrospray parameters have been carefully optimized to reach high sensitivity and precision. Separation was carried out in a 96 cm total length fused-silica capillary (50 microm id, 360 microm od) using 60 mM ammonium acetate at pH 6.0 as running buffer. Lomefloxacin was used as internal standard. MS/MS experiments were carried out using an IT as analyzer operating in multiple reaction monitoring mode to achieve the minimum number of identification points established by the 2002/657/EC European Decision. The use of an SPE procedure in two steps, combining Oasis hydrophilic-liphophilic balance and Alumina N cartridges provide a satisfactory preconcentration and clean up treatment for meat samples after extraction of the compounds with ACN. Only Oasis hydrophilic-liphophilic balance cartridges were necessary in water samples to obtain adequate recoveries. The method has been characterized for its use in meat and water samples, using matrix-matched calibrations. For chicken muscle samples, LODs between 8 and 12 microg/kg have been obtained, in all cases lower than the maximum residue limits permitted. For water samples LODs from 0.18 to 0.26 microg/L could ensure its satisfactory application in aquatic samples. PMID:19391147

  2. 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

  3. Determination of gamma-hydroxybutyric acid in human urine by capillary electrophoresis with indirect UV detection and confirmation with electrospray ionization ion-trap mass spectrometry.

    PubMed

    Baldacci, Andrea; Theurillat, Regula; Caslavska, Jitka; Pardubská, Helena; Brenneisen, Rudolf; Thormann, Wolfgang

    2003-03-21

    Gamma-hydroxybutyric acid (GHB), a minor metabolite or precursor of gamma-aminobutyric acid (GABA), acts as a neurotransmitter/neuromodulator via binding to GABA receptors and to specific presynaptic GHB receptors. Based upon the stimulatory effects, GHB is widely abused. Thus, there is great interest in monitoring GHB in body fluids and tissues. We have developed an assay for urinary GHB that is based upon liquid-liquid extraction and capillary zone electrophoresis (CZE) with indirect UV absorption detection. The background electrolyte is composed of 4 mM nicotinic acid (compound for indirect detection), 3 mM spermine (reversal of electroosmosis) and histidine (added to reach a pH of 6.2). Having a 50 microm I.D. capillary of 40 cm effective length, 1-octanesulfonic acid as internal standard, solute detection at 214 nm and a diluted urine with a conductivity of 2.4 mS/cm, GHB concentrations > or = 2 microg/ml can be detected. Limit of detection (LOD) and limit of quantitation (LOQ) were determined to be dependent on urine concentration and varied between 2-24 and 5-60 microg/ml, respectively. Data obtained suggest that LOD and LOQ (both in microg/ml) can be estimated with the relationships 0.83 kappa and 2.1 kappa, respectively, where kappa is the conductivity of the urine in mS/cm. The assay was successfully applied to urines collected after administration of 25 mg sodium GHB/kg body mass. Negative electrospray ionization ion-trap tandem mass spectrometry was used to confirm the presence of GHB in the urinary extract via selected reaction monitoring of the m/z 103.1-->m/z 85.1 precursor-product ion transition. Independent of urine concentration, this approach meets the urinary cut-off level of 10 microg/ml that is required for recognition of the presence of exogenous GHB. Furthermore, data obtained with injection of plain or diluted urine indicate that CZE could be used to rapidly recognize GHB amounts (in microg/ml) that are > or = 4 kappa. PMID:12685588

  4. Multiresidue pesticide analysis in fresh produce by capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) and -tandem mass spectrometry (GC-MS/MS).

    PubMed

    Wong, Jon W; Zhang, Kai; Tech, Katherine; Hayward, Douglas G; Makovi, Carolyn M; Krynitsky, Alexander J; Schenck, Frank J; Banerjee, Kaushik; Dasgupta, Soma; Brown, Don

    2010-05-26

    A multiresidue method for the analysis of pesticides in fresh produce has been developed using salt-out acetonitrile extraction, solid-phase dispersive cleanup with octadecyl-bonded silica (C(18)), and graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, followed by capillary gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). Quantitation was determined from calibration curves using matrix-matched standards ranging from 3.3 to 6667 ng/mL with r(2) > 0.99, and geometric mean limits of quantitation were typically 8.4 and 3.4 microg/kg for GC-MS/SIM and GC-MS/MS, respectively. Identification was determined by using target and qualifier ions and qualifier-to-target ratios for GC-MS/SIM and two ion transitions for GC-MS/MS. Fortification studies (10, 25, 100, and 500 microg/kg) were performed on 167 organohalogen, organophosphorus, and pyrethroid pesticides in 10 different commodities (apple, broccoli, carrot, onion, orange, pea, peach, potato, spinach, and tomato). The mean percent recoveries were 90 +/- 14, 87 +/- 14, 89 +/- 14, and 92 +/- 14% for GC-MS/SIM and 95 +/- 22, 93 +/- 14, 93 +/- 13, and 97 +/- 13% for GC-MS/MS at 10, 25, 100, and 500 microg/kg, respectively. GC-MS/MS was shown to be more effective than GC-MS/SIM due to its specificity and sensitivity in detecting pesticides in fresh produce samples. The method, based on concepts from the multiresidue procedure used by the Canadian Food Inspection Agency and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe), was shown to be efficient in screening, identifying, and quantitating pesticides in fresh produce samples. PMID:20199080

  5. Single-Cell Metabolite Profiling of Stalk and Glandular Cells of Intact Trichomes with Internal Electrode Capillary Pressure Probe Electrospray Ionization Mass Spectrometry.

    PubMed

    Nakashima, Taiken; Wada, Hiroshi; Morita, Satoshi; Erra-Balsells, Rosa; Hiraoka, Kenzo; Nonami, Hiroshi

    2016-03-15

    In this report, we developed the pressure probe electrospray ionization-mass spectrometry with internal electrode capillary (IEC-PPESI-MS) which enables high spatial-resolution cell sampling, precise postsampling manipulation, and high detection sensitivity. Using this technique, a comparative in situ single-cell metabolite profiling of stalk and glandular cells, the two adjacent cell types comprising a trichome unit in tomato plants (Solanum lycopersicum L.), were performed to clarify the extent of metabolic differentiation between two cell types as well as among different types of trichomes. Owing to high sensitivity of the system, less than a picoliter cell sap from a single stalk cell sufficiently yielded a number of peaks of amino acids, organic acids, carbohydrates, and flavonoids. The minimal cell sap removal from a stalk cell without severe disturbance of trichome structure enabled sequential analysis of adjacent glandular cell on the same trichome, which showed the presence of striking differences in metabolite compositions between two adjacent cell types. Comparison among different types of trichome also revealed significant variations in metabolite profiles, particularly in flavonoids and acyl sugars compositions. Some metabolites were found only in specific cell types or particular trichome types. Although extensive metabolomics analysis of glandular cells of tomato trichomes has been previously documented, this is the first report describing cell-to-cell variations in metabolite compositions of stalk and glandular cells as well as in different trichome types. Further application of this technique may provide new insights into distinct metabolism in plant cells displaying variations in shape, size, function and physicochemical properties. PMID:26845634

  6. Identification of phosphorylated peptides from complex mixtures using negative-ion orifice-potential stepping and capillary liquid chromatography/electrospray ionization mass spectrometry.

    PubMed

    Ding, J; Burkhart, W; Kassel, D B

    1994-01-01

    A rapid method for identifying and characterizing sites of phosphorylation of peptides and proteins is described. High-performance capillary liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS) is used to distinguish non-phosphorylated and phosphorylated peptides originating from mixtures as complex as enzyme digests. The method relies on the ability to produce a fragment ion characteristic and unique to phosphopeptides (m/z 79, PO3) by stepping the orifice potential of the mass spectrometer as a function of mass. At low m/z values, a high orifice potential is applied to induce extensive fragmentation of the peptide, leading to the formation of the m/z 79 phosphate-derived ion. This method is analogous to that described by Carr et al. for the identification of glycopeptides from enzymatic digestion of glycoproteins (S.A. Carr, M.J. Huddleston, M.F. Bean, Protein Science 2, 183 (1993)). The method was first evaluated and validated for a mixture of non-, mono- and di-phosphorylated synthetic peptides. Both mono- and di-phosphorylated peptides were found to generate fragment ions characteristic of PO3 whereas the non-phosphorylated peptide did not. Application of the method was extended to identifying phosphopeptides generated from an endoprotease Lys-C digestion of beta-casein. Both the expected mono- and tetra-phosphorylated Lys-C peptides were observed and identified rapidly in the LC/SEI-MS analysis. The procedure was used additionally to identify the site(s) of phosphorylation of the cytosolic non-receptor tyrosine kinase, pp60(c-src). PMID:8118063

  7. Component-resolved diagnostic of cow's milk allergy by immunoaffinity capillary electrophoresis-matrix assisted laser desorption/ionization mass spectrometry.

    PubMed

    Gasilova, Natalia; Girault, Hubert H

    2014-07-01

    Component-resolved diagnostic (CRD) of cow's milk allergy has been performed using immunoaffinity capillary electrophoresis (IACE) coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). First, total IgE quantification in the blood serum of a milk allergic patient by the IACE-UV technique was developed using magnetic beads (MBs) coated with antihuman IgE antibodies (Abs) to perform the general allergy diagnosis. Then, the immunocomplex of antihuman IgE Abs with the patient IgE Abs, obtained during the total IgE analysis, was chemically cross-linked on the MBs surface. Prepared immunosupport was used for the binding of individual milk allergens to identify the proteins triggering the allergy by IACE with UV and MALDI MS detection. Then, allergy CRD was also performed directly with milk fractions. Bovine serum albumin, lactoferrin, and α-casein (S1 and S2 forms, as was revealed by MALDI MS) were found to bind with the extracted IgE Abs, indicating that the chosen patient is allergic to these proteins. The results were confirmed by performing classical enzyme-linked immunosorbent assay of total and specific IgE Abs. The present IACE-UV/MALDI MS method required only 2 μL of blood serum and allowed the performance of the total IgE quantification and CRD of the food allergy not only with the purified allergen molecules but also directly with the food extract. Such an approach opens the possibility for direct identification of allergens molecular mass and structure, discovery of unusual allergens, which could be useful for precise personalized allergy diagnostic, allergens epitope mapping, and cross-reactivity studies. PMID:24915289

  8. Coaxial capillary and conductive capillary interfaces for collection of fractions isolated by capillary electrophoresis

    SciTech Connect

    Chiu, R.W.; Walker, K.L.; Hagen, J.J.; Monning, C.A.; Wilkins, C.L.

    1995-11-15

    An instrument is described that allows the automated collection of fractions isolated by capillary electrophoresis. This instrument allows the electrical connection to be established with the separation capillary by using a coaxial capillary flow cell or by treating the outer surface of the capillary with a gold-filled epoxy to allow electrophoresis. The coaxial interface is most useful when the electroosmotic flow in the capillary is small, and the conductive capillary interface is favored when dilution and contamination of the sample must be minimized. Both geometries permit closely spaced fractions to be acquired with minimal cross-contamination and dilution. Sample recoveries were better than 80% and virtually independent of the chemical characteristics of the sample. Fractions isolated with this instrument were successfully analyzed by high-pressure liquid chromatography and electrospray mass spectrometry. 25 refs., 4 figs.

  9. 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

  10. Optimization of capillary electrophoresis?inductively coupled plasma mass spectrometry for species analysis of metallothionein-like proteins extracted from liver tissues of Elbe-bream and Roe deer

    NASA Astrophysics Data System (ADS)

    Pröfrock, Daniel; Prange, Andreas; Schaumlöffel, Dirk; Ruck, Wolfgang

    2003-08-01

    Species analysis of metallothionein-like proteins (MLP) in liver tissues from Elbe-Bream ( Abramis brama L.) and Roe Deer ( Capreolus capreolus L.) using capillary electrophoresis (CE) combined with inductively coupled plasma mass spectrometry detection is described. In order to allow systematic development of the method, commercially available metallothionein (MT) preparations of rabbit liver were used. Optimum separation efficiency was obtained by investigating the influence of parameters such as voltage, capillary temperature, buffer concentration, buffer pH and the use of different buffer systems. Instrumental parameters such as CE capillary position, interface adjustment and contamination problems are also discussed. Separation was performed using uncoated fused silica capillaries with 75 μm i.d. and 70 cm length. The optimum conditions were found to be: Separation voltage 30 kV, positive polarity, capillary temperature 288.15 K and a buffer concentration of 100 mmol l -1 Tricine-NH 3 adjusted to pH 7.2. Sample preparation was performed so as to minimize oxidation and heavy metal contamination of the samples. The high molecular mass protein matrix was reduced by acetonitrile precipitation. For commercial MT preparations the relative standard deviations (R.S.D) in the retention times were 0.9% for MT-1 and 1.9% for MT-2; the R.S.D.'s in the peak areas were less than 6% for MT-1 and 16% for MT-2, respectively. Under optimized conditions the MLPs in the real samples could be separated efficiently in less than 10 min. By comparison with the migration times of commercially available MT preparations, two of the observed peaks could be assigned to MT-1 and MT-2.

  11. 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

  12. 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%. PMID:25865795

  13. 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.

  14. 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.

  15. Capillary Electrophoresis-Nanoelectrospray Ionization-Selected Reaction Monitoring Mass Spectrometry via a True Sheathless Metal-Coated Emitter Interface for Robust and High-Sensitivity Sample Quantification.

    PubMed

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

    2016-04-19

    A new sheathless transient capillary isotachophoresis (CITP)/capillary zone electrophoresis (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 electrochemical reaction inside 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 below 5 attomole. PMID:27028594

  16. TiO₂ nanoparticles functionalized monolithic capillary microextraction online coupled with inductively coupled plasma mass spectrometry for the analysis of Gd ion and Gd-based contrast agents in human urine.

    PubMed

    Liu, Xiaolan; Chen, Beibei; Zhang, Lin; Song, Shiyao; Cai, Yabing; He, Man; Hu, Bin

    2015-09-01

    In this work, a novel method of TiO2 nanoparticles (NPs) functionalized monolithic capillary microextraction (CME) online coupling with inductively coupled plasma mass spectrometry (ICPMS) was developed for the sequential determination of Gd(3+) and Gd-based contrast agents in human urine samples. The monolithic capillary was prepared by embedding anatase TiO2 NPS in the poly(methacrylic acid-ethylene glycol dimethacrylate) (MAA-EDMA) framework. The Gd(3+) and Gd-based contrast agents (such as gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) and Gd-DTPA-bismethylamide (Gd-DTPA-BMA)) display different adsorption behaviors on the prepared monolithic capillary which possesses the adsorption properties of both anatase TiO2 NPS and poly(MAA-EDMA) monolith. Under the optimized conditions, the limits of detection (LODs) were found to be 3.6, 3.2, and 4.5 ng L(-1) for Gd(3+), Gd-DTPA, and Gd-DTPA-BMA, respectively, which are the lowest up to date. The enrichment factor was 25-fold with the sample throughput of 5 h(-1). The proposed method was validated by the analysis of Gd(3+) and Gd-DTPA in the healthy human urine samples as well as Gd(3+) and Gd-DTPA-BMA in patient urine samples. It was found that only a small amount of the free Gd(3+) was released from Gd-DTPA-BMA, and accurate results could be obtained since no oxidation/reduction or subtraction is involved in this method. This method is simple, sensitive, and rapid and provides a very attractive nonchromatography strategy for the speciation of Gd(3+) and Gd-based contrast agents in urine samples. PMID:26239367

  17. 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.

  18. 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. PMID:27473481

  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

    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. PMID:25863379

  20. 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

  1. 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.

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

    PubMed

    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

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

    PubMed

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

    2011-08-01

    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. 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.

  5. 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. PMID:22012690

  6. 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. PMID:26530449

  7. 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. PMID:26838404

  8. 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.

  9. 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.

  10. 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. PMID:17256811

  11. Capillary and nano-liquid chromatography-tandem mass spectrometry for the quantification of small molecules in microdialysis samples: comparison with microbore dimensions.

    PubMed

    Lanckmans, Katrien; Van Eeckhaut, Ann; Sarre, Sophie; Smolders, Ilse; Michotte, Yvette

    2006-10-27

    Enhanced sensitivity is a well known benefit of miniaturised LC-electrospray (ESI)-MS/MS methods. The suitability of miniaturised LC-MS/MS for quantification of small molecules in dialysates was investigated using the anti-epileptic drug oxcarbazepine, its active metabolite, 10,11-dihydro-10-hydroxycarbamazepine, and the internal standard for microdialysis probe calibration, 2-methyl-5H-dibenz(b,f)azepine-5-carboxamide, as test compounds. ESI-MS detection is sensitive to matrix effects. Therefore, dialysate matrix effects were investigated by comparing the responses of standards made in water, Ringer's solution (salt solution used as perfusion fluid) and blank dialysate matrix. Due to the occurrence of ion suppression or enhancement, direct injection of dialysis samples onto the analytical column could not be applied for quantification of small molecules in dialysis samples. Column switching was necessary for desalting and preconcentration of the dialysates. However, this approach was not able to completely eliminate salt effects when the injection volume exceeded 1 microL. No differences in response between Ringer's solution and dialysate matrix were detected at capillary and nano-dimensions. Calibration standards should be prepared with Ringer's solution instead of water for quantitative analysis of microdialysates. A microbore, capillary and nano-LC-ESI-MS/MS method were compared in terms of method feasibility, linearity, sensitivity, accuracy and precision. Downscaling to capillary and nano-dimensions resulted in a gain in detection sensitivity of 5 and 50, respectively. Miniaturised LC-MS/MS was found to be fit for quantification of small molecules in dialysates with acceptable accuracy and method precision. PMID:16938304

  12. 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

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

    2013-06-01

    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

  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. PMID:14670034

  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. PMID:22451051

  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. Simultaneous measurements of endogenous and deuterium-labelled tracer variants of androstenedione and testosterone by capillary gas chromatography-mass spectrometry.

    PubMed

    Furuta, T; Kusano, K; Kasuya, Y

    1990-01-26

    A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of androstenedione and testosterone in human plasma using [19,19,19-2H3]androstenedione and [19,19,19-2H3]testosterone as internal standards is described. For calculation of plasma androstenedione and testosterone, peak heights were measured by selected-ion monitoring of the molecular ions of the heptafluorobutyryl derivatives of androstenedione and [2H3]androstenedione (m/z 482 and 485) and of testosterone and [2H3]testosterone (m/z 680 and 683). The isotope dilution method needed no complex corrections for contributions and provides a sensitive and reliable technique with good accuracy, precision and reproducibility. PMID:2338435

  17. 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. PMID:24141390

  18. 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.

  19. 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

  20. 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. PMID:26916593

  1. Quantitation of sunitinib, an oral multitarget tyrosine kinase inhibitor, and its metabolite in urine samples by nonaqueous capillary electrophoresis time of flight mass spectrometry.

    PubMed

    Rodríguez, Juana; Castañeda, Gregorio; Muñoz, Lorena; Villa, Jose C

    2015-07-01

    A rapid, sensitive, and specific method was developed and validated using a nonaqueous-capillary electrophoresis method with TOF-MS for determination of sunitinib and N-desethyl sunitinib in human urine. In order to avoid ionic suppression a urine samples dilution with methanol 1:10 previous step was used. This was the only treatment step to urine samples before the injection. Despite this dilution of the urine, the detection limit was as low as 0.07 mg/L for sunitinib and 0.15 mg/L for N-desethyl sunitinib. Separation of compounds was achieved with a mixture of 5 mM ammonium formate in methanol. The calibration curves were linear over the range of 0.5-50.0 mg/L for the two analyzed compounds. The within-run and between-run precisions were within 5%, while the accuracy ranged from 96.0 to 100.4%. This method can be used in routine clinical practice to monitor sunitinib and N-desethyl sunitinib drugs in the urine of cancer patients treated with once daily administration. PMID:25873554

  2. Fully automatic sample treatment by integration of microextraction by packed sorbents into commercial capillary electrophoresis-mass spectrometry equipment: application to the determination of fluoroquinolones in urine.

    PubMed

    Morales-Cid, Gabriel; Cárdenas, Soledad; Simonet, Bartolomé M; Valcárcel, Miguel

    2009-04-15

    This paper describes a new and innovative way to integrate microextraction by packed sorbents (MEPS) into commercial CE equipment. The suggested integration allows the automatic sample cleanup and preconcentration requiring only a few microliters of sample and no additional hardware and software. The MEPS was integrated in the outlet region of a commercial CE equipment cartridge in order to provide easy manipulation and exchange. The robustness of the proposed integration was demonstrated by the design and use of a (MEPS)-nonaqueous capillary electrophoresis (NACE)-MS method used to determine fluoroquinolones "FQs" (namely, ofloxacin, marbofloxacin, enrofloxacin, danofloxacin, and difloxacin) in urine. The method allows the analysis of micrograms per liter of FQs to be carried out with only 48 microL of urine sample. The obtained LODs were in the range 6.3-10.6 microg/L. An analysis of spiked urine samples was used to validate the method. Absolute recoveries were in the range of 71-109% while the precision expressed as repetitivity of peak area was lower than 5.9%. PMID:19284777

  3. Investigation of corrosion behavior of biodegradable magnesium alloys using an online-micro-flow capillary flow injection inductively coupled plasma mass spectrometry setup with electrochemical control

    NASA Astrophysics Data System (ADS)

    Ulrich, A.; Ott, N.; Tournier-Fillon, A.; Homazava, N.; Schmutz, P.

    2011-07-01

    The development of biodegradable metallic materials designed for implants or medical stents is new and is one of the most interesting new fields in material science. Besides biocompatibility, a detailed understanding of corrosion mechanisms and dissolution processes is required to develop materials with tailored degradation behavior. The materials need to be sufficiently stable as long as they have to fulfill their medical task. However, subsequently they should dissolve completely in a controlled manner in terms of maximum body burden. This study focuses on the elemental and time resolved dissolution processes of a magnesium rare earth elements alloy which has been compared to pure magnesium with different impurity level. The here described investigations were performed using a novel analytical setup based on a micro-flow capillary online-coupled via a flow injection system to a plasma mass spectrometer. Differences in element-specific and time-dependent dissolution were monitored for various magnesium alloys in contact with sodium chloride or mixtures of sodium and calcium chloride as corrosive media. The dissolution behavior strongly depends on bulk matrix elements, secondary alloying elements and impurities, which are usually present even in pure magnesium.

  4. 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

    2015-04-01

    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. PMID:25725958

  5. Capillary electrophoresis-electrospray mass spectrometry and HR-ICP-MS for the detection and quantification of 10B-boronophenylalanine (10B-BPA) used in boron neutron capture therapy.

    PubMed

    Pitois, Aurélien; de las Heras, Laura Aldave; Zampolli, Antonella; Menichetti, Luca; Carlos, Ramon; Lazzerini, Guido; Cionini, Luca; Salvatori, Pietro Alberto; Betti, Maria

    2006-02-01

    Boron neutron capture therapy (BNCT) is a bimodal radiotherapeutic treatment based on the irradiation of neoplastic tissues with neutrons after the tissues have selectively accumulated molecules loaded with nuclides with large neutron capture cross-sections (such boron-10). Boron-10 carriers have been tested to a limited extent, and clinical trials have been conducted on sulfhydryl borane (10B-BSH) and boronophenylalanine (10B-BPA). However, precise and accurate measurements of boron-10 concentrations (0.1-100 microg/g) in specimens and samples of limited size (microg scale) are needed in order to be able to biologically characterise new compounds in predictive tissue dosimetry, toxicology and pharmacology studies as well as in clinical investigations. A new approach based on fast separation and detection of 10B-BPA performed by coupling capillary electrophoresis to electrospray mass spectrometry is reported. This method allows the quantitative analysis and characterisation of 10B-BPA in a short time with a high separation efficiency. Detection limits of 3 microM for 10B-BPA and 30 ng/mL for 10B were obtained with CE-ESI-MS. A quantification limit of 10 microM for 10B-BPA (100 ng/mL for 10B) was attained. The total boron-10 concentration was determined by high-resolution inductively coupled mass spectrometry in order to validate the method. Boron-10 isotope measurements were carried out by HR-ICP-MS at medium resolution (R=4000) due to the presence of an isobaric interference at mass 10. Good agreement was obtained between the values from CE-ESI-MS and those from HR-ICP-MS. The method has been successfully used to determine the 10B-BPA in two lines of cultured cells. PMID:16372182

  6. Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus x canadensis leaves by LC-(+)ESI-MS and capillary liquid chromatography/frit-fast atom bombardment mass spectrometry.

    PubMed

    Tarkowská, Danuse; Dolezal, Karel; Tarkowski, Petr; Astot, Crister; Holub, Jan; Fuksová, Kvetoslava; Schmülling, Thomas; Sandberg, Göran; Strnad, Miroslav

    2003-04-01

    A search for naturally occurring aromatic cytokinins (ARCKs) in Arabidopsis thaliana plants and Populus x canadensis leaves led to the discovery of four new plant hormone substances: 6-(2-methoxybenzylamino)purine (ortho-methoxytopolin, MeoT), 6-(3-methoxybenzylamino)purine (meta-methoxytopolin, MemT) (Fig. 1) and their 9-beta-D-ribofuranosyl derivatives. These substances were identified by liquid chromatography electrospray ionization mass spectrometry [LC (+)ESI-MS] and capillary-liquid chromatography/frit-fast atom bombardment-mass spectrometry [CapLC/frit-FAB-MS] after pre-column derivatization. The chemical structures were subsequently confirmed by chemical synthesis. Because of lack of heavy labelled internal standards, the endogenous levels of methoxytopolins in A. thaliana plants, Populus x canadensis leaves and samples derived from cultures of Agrobacterium tumefaciens strain GV3101 were determined by enzyme-linked immunosorbent assay (ELISA) of HPLC-fractionated extracts. While the levels of MeoT, MemT and their ribosides in A. thaliana shoots and Populus x canadensis leaves were relatively low (approximately 0.25-10 pmol g-1 FW for MeoT and MemT, respectively), the A. tumefaciens strain produced up to 600 times more of the newly identified substances. Cytokinin activity of methoxytopolines was demonstrated in three bioassays testing their ability to stimulate tobacco callus growth, to delay chlorophyll degradation in excised wheat leaves, and to induce betacyanin synthesis in Amaranthus caudatus var. atropurpurea cotyledons. Notably, their anti-senescing activity in the wheat leaf assay exceeded that of BAP and Z by almost 200%. Methoxytopolins are proposed to be new members of the biologically active aromatic cytokinin family, which might have specific physiological functions. PMID:12675749

  7. 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. PMID:18314967

  8. 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.

  9. 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 M.

    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.

  10. Quantification of oxidative DNA lesions in tissues of Long-Evans Cinnamon rats by capillary high-performance liquid chromatography-tandem mass spectrometry coupled with stable isotope-dilution method.

    PubMed

    Wang, Jin; Yuan, Bifeng; Guerrero, Candace; Bahde, Ralf; Gupta, Sanjeev; Wang, Yinsheng

    2011-03-15

    The purpose of our study was to develop suitable methods to quantify oxidative DNA lesions in the setting of transition metal-related diseases. Transition metal-driven Fenton reactions constitute an important endogenous source of reactive oxygen species (ROS). In genetic diseases with accumulation of transition metal ions, excessive ROS production causes pathophysiological changes, including DNA damage. Wilson's disease is an autosomal recessive disorder with copper toxicosis due to deficiency of ATP7B protein needed for excreting copper into bile. The Long-Evans Cinnamon (LEC) rat bears a deletion in Atp7b gene and serves as an excellent model for hepatic Wilson's disease. We used a sensitive capillary liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS/MS) method in conjunction with the stable isotope-dilution technique to quantify several types of oxidative DNA lesions in the liver and brain of LEC rats. These lesions included 5-formyl-2'-deoxyuridine, 5-hydroxymethyl-2'-deoxyuridine, and the 5'R and 5'S diastereomers of 8,5'-cyclo-2'-deoxyguanosine and 8,5'-cyclo-2'-deoxyadenosine. Moreover, the levels of these DNA lesions in the liver and brain increased with age and correlated with age-dependent regulation of the expression of DNA repair genes in LEC rats. These results provide significant new knowledge for better understanding the implications of oxidative DNA lesions in transition metal-induced diseases, such as Wilson's disease, as well as in aging and aging-related pathological conditions. PMID:21323344

  11. Application of capillary electrophoresis-inductively coupled plasma mass spectrometry to comparative studying of the reactivity of antitumor ruthenium(III) complexes differing in the nature of counter-ion toward human serum proteins.

    PubMed

    Połeć-Pawlak, Kasia; Abramski, Jan K; Ferenc, Julia; Foteeva, Lidia S; Timerbaev, Andrei R; Keppler, Bernhard K; Jarosz, Maciej

    2008-05-30

    Varying the counter-ion is a highly supportive practice in tackling the problem of poor water-solubility of metal complexes of pharmaceutical importance. As a matter of fact, the relevant structural modification may alter the metabolic pathways and possibly the mode of action of a drug. To prove that this does not take place for one of the lead anticancer metal-based developmental compounds, indazolium trans-[RuCl(4)(1H-indazole)(2)] (KP1019), its reactivity toward human serum proteins was assessed under simulated physiological conditions and compared to that of a much more soluble analogue, sodium trans-[RuCl(4)(1H-indazole)(2)] (KP1339). For such kinetic assaying, capillary electrophoresis (CE) interfaced online with inductively coupled plasma mass spectrometry (ICP-MS) to specifically monitor changes in the metal speciation following the formation of ruthenium-protein adducts was applied. The rate constants of interaction with albumin and transferrin were determined at pharmacologically fitting drug-to-protein ratios as on average 0.0319+/-0.0021 min(-1) and 0.0931+/-0.0019 min(-1) (KP1019) and 0.0316+/-0.0018 min(-1) and 0.0935+/-0.0053 min(-1) (KP1339), respectively. The results of this brief study showed that changing from organic to inorganic counter-ion at the stage of formulation could commonly be recommended for improving ruthenium-based drug solubility and bioavailability. PMID:18433763

  12. 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

  13. 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

    2015-01-01

    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, 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. PMID:25585609

  14. 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

  15. 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

  16. Capillary muscle.

    PubMed

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-05-19

    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

  17. Label-free Quantification of Proteins in Single Embryonic Cells with Neural Fate in the Cleavage-Stage Frog (Xenopus laevis) Embryo using Capillary Electrophoresis Electrospray Ionization High-Resolution Mass Spectrometry (CE-ESI-HRMS).

    PubMed

    Lombard-Banek, Camille; Reddy, Sushma; Moody, Sally A; Nemes, Peter

    2016-08-01

    Quantification of protein expression in single cells promises to advance a systems-level understanding of normal development. Using a bottom-up proteomic workflow and multiplexing quantification by tandem mass tags, we recently demonstrated relative quantification between single embryonic cells (blastomeres) in the frog (Xenopus laevis) embryo. In this study, we minimize derivatization steps to enhance analytical sensitivity and use label-free quantification (LFQ) for single Xenopus cells. The technology builds on a custom-designed capillary electrophoresis microflow-electrospray ionization high-resolution mass spectrometry platform and LFQ by MaxLFQ (MaxQuant). By judiciously tailoring performance to peptide separation, ionization, and data-dependent acquisition, we demonstrate an ∼75-amol (∼11 nm) lower limit of detection and quantification for proteins in complex cell digests. The platform enabled the identification of 438 nonredundant protein groups by measuring 16 ng of protein digest, or <0.2% of the total protein contained in a blastomere in the 16-cell embryo. LFQ intensity was validated as a quantitative proxy for protein abundance. Correlation analysis was performed to compare protein quantities between the embryo and n = 3 different single D11 blastomeres, which are fated to develop into the nervous system. A total of 335 nonredundant protein groups were quantified in union between the single D11 cells spanning a 4 log-order concentration range. LFQ and correlation analysis detected expected proteomic differences between the whole embryo and blastomeres, and also found translational differences between individual D11 cells. LFQ on single cells raises exciting possibilities to study gene expression in other cells and models to help better understand cell processes on a systems biology level. PMID:27317400

  18. 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.

  19. Analysis of Stevia glycosides by capillary electrophoresis.

    PubMed

    Mauri, P; Catalano, G; Gardana, C; Pietta, P

    1996-02-01

    The determination of diterpene glycosides from Stevia rebaudiana leaves using capillary electrophoresis is described. Analyses were performed on fused silica capillaries with 20 mM sodium tetraborate buffer, pH 8.3, and 30 mM sodium dodecyl sulfate. The effect of the organic solvent injected with the sample solution on the electrophoretic solution has been confirmed, and an absolute amount of 1.6 nL per injected sample was optimal. Rebaudioside A and steviolbioside were isolated by semipreparative high performance liquid chromatography (HPLC), and their structure was assessed by mass spectrometry. PMID:8900944

  20. 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.

  1. 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.

  2. TEACHING PHYSICS: Capillary effects

    NASA Astrophysics Data System (ADS)

    Ivanov, Dragia; Petrova, Hristina

    2000-07-01

    We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY...

    EPA Science Inventory

    Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species. Selenate (SeVI) was reduced on-line to selenite (SeIV) by mixing the CE effluent with concentrated HCl. A microporou...

  12. Analysis of atrazine, terbutylazine and their N-dealkylated chloro and hydroxy metabolites by solid-phase extraction and gas chromatography-mass spectrometry and capillary electrophoresis-ultraviolet detection.

    PubMed

    Loos, R; Niessner, R

    1999-03-12

    Solid-phase extraction (SPE) with the styrene-divinylbenzene adsorbent LiChrolut EN was investigated for the extraction of the s-triazine herbicides atrazine and terbutylazine, their polar N-dealkylated degradation products deethylatrazine (DEA), deisopropylatrazine (DIA) and deethylterbutylazine (DET) and for the hydrophilic hydroxytriazine degradation products (HTDPs) hydroxyatrazine (HA), hydroxyterbutylazine (HT), deethylhydroxyatrazine (DEHA), deisopropylhydroxyatrazine (DIHA) and deethyldeisopropylhydroxyatrazine (ameline). The optimum pH value for the extraction of the HTDPs from fortified tap water at 2 micrograms/l is 3.0. Recovery values with 200 mg LiChrolut EN are > 80% for HA, HT, DEHA and 30% for DIHA from 200 ml spiked tap and river water. Atrazine, terbutylazine, DEA, DIA and DET are quantitatively extracted by LiChrolut EN. The chlorotriazines are analyzed by GC-MS and the HTDPs by capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) with an acetate buffer at pH 4.6 or a sodium borate-sodium dodecyl sulfate buffer at pH 9.3. The combined method of SPE enrichment and CE analysis allows the determination of HTDPs in the low microgram/l range. PMID:10220922

  13. Sensitive determination of polycyclic aromatic hydrocarbons in water samples using monolithic capillary solid-phase extraction and on-line thermal desorption prior to gas chromatography-mass spectrometry.

    PubMed

    Galán-Cano, Francisco; Bernabé-Zafón, Virginia; Lucena, Rafael; Cárdenas, Soledad; Herrero-Martínez, José Manuel; Ramis-Ramos, Guillermo; Valcárcel, Miguel

    2011-04-01

    A methacrylate-based monolithic capillary column has been evaluated for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. For this purpose, the monolyte was in situ synthesized in a 6cm×0.32mm id fused-silica capillary. The microextraction unit was fitted to a micro-HPLC pump to pass 10mL of sample. The isolated pollutants were eluted by means of 10μL of methanol, the organic phase being directly collected in a specific interface that can be fitted to the injection port of the gas chromatograph without modification. The interface allows the on-line thermal desorption of the PAHs, avoiding the dilution and providing enough sensitivity to reach the legal limits established for these pollutants in the matrices selected. The limits of detection achieved for 10mL of water ranged between 2.8ng/L (indeno(1,2,3-cd)pyrene) and 11.5ng/L (acenaphthene) with acceptable precision (between 4.5 and 18.2% RSD). The method was applied to the determination of the selected PAHs in tap, river waters and sewage, being fluoranthene and pyrene detected in all of them at concentrations lower than the legal limits established for these compounds in the matrices assayed. PMID:21377161

  14. 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.

  15. 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. PMID:26331950

  16. 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.

  17. 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.

  18. Combining tissue extraction and off-line capillary electrophoresis matrix-assisted laser desorption/ionization Fourier transform mass spectrometry for neuropeptide analysis in individual neuronal organs using 2,5-dihydroxybenzoic acid as a multi-functional agent.

    PubMed

    Wang, Junhua; Jiang, Xiaoyue; Sturm, Robert M; Li, Lingjun

    2009-11-20

    In this study we report an improved protocol that combines simplified sample preparation and micro-scale separation for mass spectrometric analysis of neuropeptides from individual neuroendocrine organs of crab Cancer borealis. A simple, one-step extraction method with commonly used matrix-assisted laser desorption/ionization (MALDI) matrix, 2,5-dihydroxybenzoic acid (DHB), in saturated aqueous solution, is employed for improved extraction of neuropeptides. Furthermore, a novel use of DHB as background electrolyte for capillary electrophoresis (CE) separation in the off-line coupling of CE to MALDI-Fourier transform mass spectrometric (FT-MS) detection is also explored. The new CE electrolyte exhibits full compatibility with MALDI-MS analysis of neuropeptides in that both the peptide extraction process and MALDI detection utilize DHB. In addition, enhanced resolving power and improved sensitivity are also observed for CE-MALDI-MS of peptide mixture analysis. Collectively, the use of DHB has simplified the extraction and reduced the sample loss by elimination of homogenizing, drying, and desalting processes. In the mean time, the concurrent use of DHB as CE separation buffer and subsequent MALDI matrix offers improved spectral quality by eliminating the interferences from typical CE electrolyte in MALDI detection. PMID:19473662

  19. 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.

  20. Semipreparative capillary electrochromatography.

    PubMed

    Chen, J R; Zare, R N; Peters, E C; Svec, F; Frechét, J J

    2001-05-01

    Capillaries with inner diameters of 550 microm have successfully been packed with 1.5-microm octadecyl silica particles using frits made of macroporous polymers by the UV photopolymerization of a solution of glycidyl methacrylate and trimethylolpropane trimethacrylate. This type of frit is found superior to one made of low-melting point poly(styrene-co-divinylbenzene) beads. Bubble formation is not observed to occur within these capillary columns under our experimental conditions. Separations can be achieved with sample injection volumes as high as 1 microL. To demonstrate its semipreparative use, a mixture of 500 nL of taxol (20 mM) and its precursor, baccatin III (30 mM), is separated using such a column with a Tris buffer. PMID:11354480

  1. 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 M.

    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.

  2. 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.

  3. 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

    2015-08-01

    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. PMID:26118803

  4. Quantification of N2-Carboxymethyl-2’-deoxyguanosine in Calf-thymus DNA and Cultured Human Kidney Epithelial Cells by Capillary HPLC-Tandem Mass Spectrometry Coupled with Stable Isotope-dilution Method

    PubMed Central

    Wang, Hongxia; Cao, Huachuan; Wang, Yinsheng

    2009-01-01

    Glyoxal is generated endogenously from the degradation of glucose and the oxidation of carbohydrates, lipids as well as the 2-deoxyribose moieties of DNA. Glyoxal is also widely used in industry and is present cigarette smoke and food. Glyoxal can conjugate with nucleobases and proteins to give advanced glycation end products. N2-carboxymethyl-2’-deoxyguanosine (N2-CMdG) and the cyclic 1,N2-glyoxal-dG are the major glyoxal adducts formed in DNA. In this study, we first assessed the stabilities of these two adducts. It turned out that 1,N2-glyoxal-dG was very unstable, with more than 70% of the adduct being decomposed to dG upon a 24-hr incubation at 37°C in phosphate buffered saline. However, N2-CMdG was very stable, less than 0.5% of the lesion was degraded to dG after a 7-day incubation under the same conditions. We further developed a sensitive capillary LC-ESI-MS/MS/MS coupled with stable isotope dilution method and quantified the formation of N2-CMdG in calf thymus DNA and 293T human kidney epithelial cells that were exposed to glyoxal and in calf thymus DNA treated with D-glucose. Our results showed that N2-CMdG was produced at 2–134 lesions per 106 nucleosides in calf thymus DNA when the surrounding glyoxal concentration was increased from 10 to 500 µM and approximately 3–27 lesions per 107 nucleosides while the D-glucose concentration changed from 2 to 50 mM. Furthermore, N2-CMdG was induced endogenously in 293T human kidney epithelial cells and exposure to glyoxal further stimulated the formation of this lesion; the level of this adduct ranged from 7 to 15 lesions per 108 nucleosides while the glyoxal concentration increased from 10 µM to 1.25 mM. Collectively, our results suggested that N2-CMdG might serve as a biomarker for glyoxal exposure. PMID:19968260

  5. High-performance liquid chromatographic, capillary electrophoretic and capillary electrophoretic-electrospray ionisation mass spectrometric analysis of selected alkaloid groups.

    PubMed

    Stöckigt, Joachim; Sheludk, Yuri; Unger, Matthias; Gerasimenko, Irina; Warzecha, Heribert; Stöckigt, Detlef

    2002-08-16

    Systems for efficient separation of selected alkaloid groups by high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and capillary electrophoresis coupled with electrospray ionisation mass spectrometry (CE-ESI-MS) are described. The optimized HPLC system was applied for the separation of 23 standard indole alkaloids as well as for qualitative and quantitative analyses of crude alkaloid extracts of Rauvolfia serpentina X Rhazya stricta hybrid cell cultures. The developed conditions for CE analysis proved to be efficient for separation of mixtures of standard indole and beta-carboline alkaloids. The described buffer system is also applicable in the combination of CE with electrospray ionisation mass spectrometry. This analytical technique allowed the separation and identification of components of standard indole alkaloid mixture as well as crude extracts of R. serpentina roots, R. serpentina cell suspension cultures and cortex of Aspidosperma quebracho-blanco. The influence of buffer composition and analyte structures on separation is discussed. PMID:12219932

  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. 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.

  8. Integration of monolithic frit into the particulate capillary (IMFPC) column in shotgun proteome analysis.

    PubMed

    Wang, Fangjun; Dong, Jing; Ye, Mingliang; Wu, Ren'an; Zou, Hanfa

    2009-10-12

    Capillary column plays an important role in nano-flow liquid chromatography coupled with tandem mass spectrometry for dealing with the high dynamic range and complexity of protein samples in shotgun proteome analysis. In this study, the integrated monolithic frit into the particulate capillary (IMFPC) column was prepared. By comparing the prepared IMFPC column with conventionally fritless capillary column, smaller size of packing materials could be easily packed into the capillary to achieve higher average peak capacity and proteome coverage. As the monolithic emitter was integrated onto this type of column, the void volume between packing particles and electrospray emitter was eliminated and the electrospray quality was improved. The prepared IMFPC column was applied to proteome analysis of mouse liver extracts, and it was observed that the number of identified proteins and peptides increased 14.9 and 12.9% as well as the peak capacity increased 11.6% by using IMFPC column over conventionally fritless capillary column. PMID:19786199

  9. Alveolar Capillary Dysplasia

    PubMed Central

    Stankiewicz, Pawel; Steinhorn, Robin H.

    2011-01-01

    Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder. PMID:21471096

  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. 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.)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Capillary interconnect device

    DOEpatents

    Renzi, Ronald F.

    2007-12-25

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) means for applying an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  19. 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.

  20. Capillaries for use in a multiplexed capillary electrophoresis system

    SciTech Connect

    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.

  1. Applications of capillary optical fibers

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard

    2006-10-01

    The paper updates and summarizes contemporary applications of capillary optical fibers. Some of these applications are straight consequence of the classical capillary properties and capillary devices like: rheometry, electrophoresis, column chromatography (gas and liquid). Some new applications are tightly connected with co-propagation (or counter-propagation) of micro-mass together with optical wave - evanescent or of considerable intensity. In the first case, the optical wave is propagated in a narrow (more and more frequently single-mode) optical ring core adjacent to the capillary hole. The optical propagation is purely refractive. In the second case, the intensity maximum of optical wave is on the capillary long axis, i.e. in the center of the hole. The optical propagation is purely photonic, i.e. in a Bragg waveguide (one dimensional photonic band-gap). The capillary hole is filled with vacuum or with propagated matter (gas, liquid, single atoms, continuous particle arrangement). Optical capillaries, filamentary and embedded, are turning to a fundamental component of nano- and micro-MOEMS.

  2. 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.

  3. Integrated multiplexed capillary electrophoresis system

    SciTech Connect

    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.

  4. 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.

  5. 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)

  6. 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.

  7. Gravity-Capillary Lumps

    NASA Astrophysics Data System (ADS)

    Akylas, Triantaphyllos R.; Kim, Boguk

    2004-11-01

    In dispersive wave systems, it is known that 1-D plane solitary waves can bifurcate from linear sinusoidal wavetrains at particular wave numbers k = k0 where the phase speed c(k) happens to be an extremum (dc/dk| _0=0) and equals the group speed c_g(k_0). Two distinct possibilities thus arise: either the extremum occurs in the long-wave limit (k_0=0) and, as in shallow water, the bifurcating solitary waves are of the KdV type; or k0 ne 0 and the solitary waves are in the form of packets, described by the NLS equation to leading order, as for gravity-capillary waves in deep water. Here it is pointed out that an entirely analogous scenario is valid for the genesis of 2-D solitary waves or `lumps'. Lumps also may bifurcate at extrema of the phase speed and do so when 1-D solitary waves happen to be unstable to transverse perturbations; moreover, they have algebraically decaying tails and are either of the KPI type (e.g. in shallow water in the presence of strong surface tension) or of the wave packet type (e.g. in deep water) and are described by an elliptic-elliptic Davey-Stewartson equation system to leading order. Examples of steady lump profiles are presented and their dynamics is discussed.

  8. Filling of charged cylindrical capillaries.

    PubMed

    Das, Siddhartha; Chanda, Sourayon; Eijkel, J C T; Tas, N R; Chakraborty, Suman; Mitra, Sushanta K

    2014-10-01

    We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because of decreased velocity gradients at the wall. Both these effects essentially stem from the spontaneous formation of an electric double layer (EDL) and the resulting streaming potential caused by the net capillary-flow-driven advection of ionic species within the EDL. Our results demonstrate that filling of charged capillaries also exhibits the well-known linear and Washburn regimes witnessed for uncharged capillaries, although the filling rate is always lower than that of the uncharged capillary. We attribute this to a competitive success of the lowering of the driving forces (because of electroviscous effects), in comparison to the effect of weaker drag forces. We further reveal that the time at which the transition between the linear and the Washburn regime occurs may become significantly altered with the introduction of surface charges, thereby altering the resultant capillary dynamics in a rather intricate manner. PMID:25375597

  9. 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.

  10. 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.

  11. 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.

  12. Nanopore Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bush, Joseph; Mihovilovic, Mirna; Maulbetsch, William; Frenchette, Layne; Moon, Wooyoung; Pruitt, Cole; Bazemore-Walker, Carthene; Weber, Peter; Stein, Derek

    2013-03-01

    We report on the design, construction, and characterization of a nanopore-based ion source for mass spectrometry. Our goal is to field-extract ions directly from solution into the high vacuum to enable unit collection efficiency and temporal resolution of sequential ion emissions for DNA sequencing. The ion source features a capillary whose tip, measuring tens to hundreds of nanometers in inner diameter, is situated in the vacuum ~ 1.5 cm away from an extractor electrode. The capillary was filled with conductive solution and voltage-biased relative to the extractor. Applied voltages of hundreds of volts extracted tens to hundreds of nA of current from the tip. A mass analysis of the extracted ions showed primarily singly charged clusters comprising the cation or anion solvated by several solvent molecules. Our interpretation of these results, based on the works of Taylor and of de la Mora, is that the applied electric stresses distort the fluid meniscus into a Taylor cone, where electric fields reach ~ 1V/nm and induce significant ion evaporation. Accordingly, the abundances of extracted ionic clusters resemble a Boltzmann distribution. This work was supported by NIH grant NHGRI 1R21HG005100-01.

  13. Advanced Capillary Liquid Chromatography-Mass Spectrometry for Proteomics

    SciTech Connect

    Shen, Yufeng; Page, Jason S.; Smith, Richard D.

    2009-02-23

    The liquid chromatography (LC)-mass spectrometric (MS) analysis of peptides has become a routine method for proteomics – the study of the entire complement of proteins e.g., expressed by a cell under a specific set of conditions at a specific time. Mixtures of peptides, such as those generated from enzymatic (e.g., trypsin) digestion of globally recovered proteins (i.e. a proteome), are typically very complex and >100,000 different molecular species may be observable using MS detection [1]. LC separations implemented prior to MS for broad protein identification have three major roles: 1) to isolate individual components or reduce complexity as much as possible, 2) to increase sensitivity by concentrating the components into narrow zones prior to MS, and 3) to eliminate or displace interfering species (e.g., salts and polymers) that may be present in proteomics samples. A desired quality of LC separation can be achieved from the use of either multiple steps of moderate quality separations, or fewer steps of high power separations. The former approach is generally more easily accessible for very high quality separations due to the variety of commercialized LC platforms available, while the latter still often requires considerable developmental efforts (for both columns and instrumentation). In addition to proteomics data quality, other differences between these two approaches include proteomics analysis time and sample consumption (and subsequent analysis costs), as well as direct impact on potential proteomics applications that have special requirements in terms of analysis coverage, sample size, dynamic range, sensitivity, and throughput.

  14. 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. PMID:26593113

  15. 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. PMID:24011728

  16. 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.

  17. Laser-based capillary polarimeter.

    PubMed

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158

  18. 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.

  19. Non-Aqueous Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Szumski, Michał; Buszewski, Bogusław

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

  20. 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.

  1. 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.

  2. Separation and identification of smokeless gunpowder additives by capillary electrochromatography.

    PubMed

    de Perre, Chloé; Corbin, Inge; Blas, Maximilien; McCord, Bruce R

    2012-12-01

    This paper details a method for the separation and identification of fourteen organic compounds commonly found as constituents in commercial smokeless powders using a hexyl acrylate-based porous monolith. Capillary electrochromatography (CEC) coupled to UV and time of flight-mass spectrometry (TOF-MS) methods were both explored. The CEC-UV method provides an effective and efficient method for the detection of all components in the additive package of the powder. The TOF-MS procedure provides better sensitivity and selectivity allowing an additional confirmation of the presence of the subset of those compounds, which are detectable via positive and/or negative ion electrospray ionization mass spectrometry. Both methods were used for the analysis of smokeless powder components in a mixed standard as well as in the determination of the composition of the additive package of individual powders. PMID:22897867

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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…

  11. Gradient elution in capillary electrochromatography

    SciTech Connect

    Anex, D.; Rakestraw, D.J.; Yan, Chao; Dadoo, R.; Zare, R.N.

    1997-08-01

    In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

  12. Capillary electrophoresis systems and methods

    DOEpatents

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

    2011-08-02

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

  13. Capillary Flow Limitations of Nanowicks

    NASA Astrophysics Data System (ADS)

    Zhang, Conan; Hidrovo, Carlos

    2009-11-01

    Thermal management is an important issue in microelectronic systems. The inaccessibility and diminishing size of these systems, however, requires that the heat management components be reliable and compact, such as is the case with heat pipes. In most intermediate temperature heat pipes typically found in microelectronics, the critical heat flux is governed by the capillary limit. Given the projected increases in computer chip heat fluxes, it is important to investigate the use of nanowicks as a means of raising this capillary limit. A theoretical model was developed to simulate flow through a vertical nanopillar array by balancing the capillary driving forces and the viscous losses in a quasi-steady state dynamic formulation. Based on this model, the maximum mass flow and its critical heat flux can be found for a wick given its microstructure geometry. These values were also found experimentally for commercially available wicks and nanowicks. We found that nanowicks provide lower mass flow rates than conventional wicks, mainly due to a reduced cross section. However, nanowicks achieved higher velocities and show promise over some conventional heat pipe wicks.

  14. Treelike networks accelerating capillary flow

    NASA Astrophysics Data System (ADS)

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006), 10.1103/PhysRevE.73.066302; J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007), 10.1103/PhysRevE.75.056301]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube.

  15. 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.

  16. Treelike networks accelerating capillary flow.

    PubMed

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006); J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007)]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube. PMID:25353880

  17. Viscous peeling with capillary suction

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Lister, John

    2014-11-01

    If an elastic tape is stuck to a rigid substrate by a thin film of viscous fluid and then peeled off by pulling at a small angle to the horizontal, then both viscous and capillary forces affect the peeling speed (McEwan and Taylor, 1966). If there is no capillary meniscus (e.g. if the peeling is due to viscous fluid being injected under the tape), then the peeling speed is given by a Cox-Voinov-like law, and is an increasing function of the peeling angle. We show that, with a meniscus present, the effect of the capillary forces is to suck down the tape, reducing the effective peeling angle and hence the peeling speed. When surface tension dominates and the peeling speed tends to zero, the system transitions to a new state whose time-evolution can be described by a system of coupled ordinary differential equations. These asymptotic results are confirmed by numerical calculations. Similar results hold for the peeling-by-bending of elastic beams, with ``angle'' replaced by ``curvature'' (i.e. bending moment).

  18. 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. PMID:24630982

  19. 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

  20. 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.

  1. 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

  2. Brain capillaries in Alzheimer's disease.

    PubMed

    Baloyannis, Stavros J

    2015-01-01

    Alzheimer's disease is the most common cause of irreversible dementia, affecting mostly the presenile and senile age, shaping a tragic profile in the epilogue of the life of the suffering people. Due to the severity and the social impact of the disease an ongoing research activity is in climax nowadays, associated with many legal, social, ethical, humanitarian, philosophical and economic considerations. From the neuropathological point of view the disease is characterized by dendritic pathology, loss of synapses and dendritic spines, affecting mostly selective neuronal networks of critical importance for memory and cognition, such as the basal forebrain cholinergic system, the medial temporal regions, the hippocampus and many neocortical association areas. Tau pathology consisted of intracellular accumulation of neurofibrillary tangles of hyperphosphorilated tau protein and accumulation of Aβ-peptide's deposits, defined as neuritic plaques, are the principal neuropathological diagnostic criteria of the disease. The neurotoxic properties of the oligomerics of the Aβ-peptide and tau mediated neurodegeneration are among the main causative factors of impaired synaptic plasticity, neuronal loss, dendritic alterations and tremendous synaptic loss. The gradual degeneration of the organelles, particularly mitochondria, smooth endoplasmic reticulum and Golgi apparatus, visualized clearly by electron microscopy (EM), emphasize the importance of the oxidative stress and amyloid toxicity in the pathogenetic cascade of the disease. The vascular factor may be an important component of the whole spectrum of the pathogenesis of AD. It is of substantial importance the concept that the structural alterations of the brain capillaries, may contribute in the pathology of AD, given that the disruption of the BBB may induce exacerbation of AD pathology, by promoting inflammation around the blood capillaries and in the neuropile space diffusely. From the morphological point of view

  3. Capillary Phenomena at Nanoscales: Electrowetting and Capillary Adhesion

    NASA Astrophysics Data System (ADS)

    Robbins, Mark

    2011-11-01

    Theories of capillary phenomena have traditionally been based on continuum approximations that break down as dimensions shrink to nanometer scales. Molecular simulations are used to test the limits of continuum theory in electrowetting on dielectric (EWOD) and capillary adhesion between solids. In EWOD, a fluid drop is separated from an electrode by a dielectric. Increasing the voltage V between drop and electrode, decreases the contact angle θ, allowing the droplet to be manipulated. Simulations of nanoscale drops show the same behavior as experiments on millimeter drops. The contact angle follows the continuum Young-Lippmann equation (YLE) at low voltages and then saturates. The saturation mechanism has been difficult to identify in experiments. Simulations show that charged molecules are pulled from the drop by large electrostatic forces near the contact line. Saturation can be delayed by increasing molecular binding, lowering temperature or increasing dielectric constant. A local force balance equation is derived that agrees with the YLE below saturation and remains valid after saturation. Simulations of capillary adhesion examined the force between a spherical tip of radius R and a flat substrate. The shape of the meniscus agrees remarkably well with continuum theory down to nanometer separations, as does the adhesive force from interfacial tension. However, the total force may deviate by factors of two or have the opposite sign. While the component of the pressure along the substrate agrees with the Laplace pressure from continuum theory, the out-of âplane component does not. There may also be significant force oscillations associated with layering near the solids. The elastic response of the solid has little affect on adhesive forces. This material is based upon work supported by National Science Foundation Grant No. CMS-0103408.

  4. 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

  5. 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.

  6. 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

  7. Intracranial capillary hemangioma mimicking a dissociative disorder

    PubMed Central

    John, Santosh G.; Pillai, Unnikrishnan; Lacasse, Alexander

    2012-01-01

    Capillary hemangiomas, hamartomatous proliferation of vascular endothelial cells, are rare in the central nervous system (CNS). Intracranial capillary hemangiomas presenting with reversible behavioral abnormalities and focal neurological deficits have rarely been reported. We report a case of CNS capillary hemangioma presenting with transient focal neurological deficits and behavioral abnormalities mimicking Ganser's syndrome. Patient underwent total excision of the vascular malformation, resulting in complete resolution of his symptoms. PMID:24765434

  8. 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.

  9. Malpighi and the discovery of capillaries.

    PubMed

    Pearce, J M S

    2007-01-01

    Leonardo da Vinci clearly observed and described capillaries. Using the microscope, Marcello Malpighi examined the brain and major organs to demonstrate their finer anatomical features. This led to his discovery in 1661, of capillaries that proved fundamental to our understanding of the vascular system in the brain and cord. He hypothesized that capillaries were the connection between arteries and veins that allowed blood to flow back to the heart in the circulation of the blood, as first asserted by William Harvey. PMID:17851250

  10. Capillary rise kinetics of some building materials.

    PubMed

    Karoglou, M; Moropoulou, A; Giakoumaki, A; Krokida, M K

    2005-04-01

    The presence of water in masonry is one of the main factors in deterioration. Capillary rise is the most usual mechanism of water penetration into building materials. In this study the kinetics of the capillary rise phenomenon was studied for various building materials: four stones, two bricks, and six plasters. A first-order kinetic model was proposed, in which the equilibrium moisture height derived from Darcy law. The capillary height time constant found to be strongly affected by the material characteristics. Moreover, the capillary height time constant can be predicted if the average pore radius of the materials is known. PMID:15752811

  11. 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

  12. 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.

  13. Microfoam formation in a capillary.

    PubMed

    Kotopoulis, Spiros; Postema, Michiel

    2010-02-01

    The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source. In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1-10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena. We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces. We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall. Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation. PMID:19875143

  14. Exotic containers for capillary surfaces

    NASA Technical Reports Server (NTRS)

    Concus, Paul; Finn, Robert

    1991-01-01

    This paper discusses 'exotic' rotationally symmetric containers that admit an entire continuum of distinct equilibrium capillary free surfaces. The paper extends earlier work to a larger class of parameters and clarifies and simplifies the governing differential equations, while expressing them in a parametric form appropriate for numerical integration. A unified presentation suitable for both zero and nonzero gravity is given. Solutions for the container shapes are depicted graphically along with members of the free-surface continuum, and comments are given concerning possible physical experiments.

  15. Microbeam-coupled capillary electrophoresis.

    PubMed

    Garty, G; Ehsan, M U; Buonanno, M; Yang, Z; Sweedler, J V; Brenner, D J

    2015-09-01

    Within the first few microseconds following a charged particle traversal of a cell, numerous oxygen and nitrogen radicals are formed along the track. Presented here is a method, using capillary electrophoresis, for simultaneous measurement, within an individual cell, of specific reactive oxygen species, such as the superoxide radical ([Formula: see text]) as well as the native and oxidised forms of glutathione, an ubiquitous anti-oxidant that assists the cell in coping with these species. Preliminary data are presented as well as plans for integrating this system into the charged particle microbeam at Columbia University. PMID:25870435

  16. Capillary rafts and their destabilization

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Abkarian, Manouk; Aristoff, Jeffrey; Stone, Howard

    2010-11-01

    Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. The study of such particle-laden interfaces is therefore of practical as well as fundamental importance. Here we report experiments on the self-assembly of spherical particles into capillary rafts at an oil-water interface and elucidate how such rafts sink. We characterize different types of sinking behavior and show that it is possible to obtain "armored droplets," whereby the sinking oil is encapsulated within a shell of particles.

  17. Capillary electrophoresis in metallodrug development.

    PubMed

    Holtkamp, Hannah; Hartinger, Christian G

    2015-09-01

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

  18. 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.

  19. Evaluation of capillary reinforced composites

    NASA Technical Reports Server (NTRS)

    Cahill, J. E.; Halase, J. F.; South, W. K.; Stoffer, L. J.

    1985-01-01

    Anti-icing of the inlet of jet engines is generally performed with high pressure heated air that is directed forward from the compressor through a series of pipes to various manifolds located near the structures to be anti-iced. From these manifolds, the air is directed to all flowpath surfaces that may be susceptible to ice formation. There the anti-icing function may be performed by either heat conduction or film heating. Unfortunately, the prospect of utilizing lighweight, high strength composites for inlet structures of jet engines has been frustrated by the low transverse thermal conductivity of such materials. It was the objective of this program to develop an advanced materials and design concept for anti-icing composite structures. The concept that was evaluated used capillary glass tubes embedded on the surface of a composite structure with heated air ducted through the tubes. An analytical computer program was developed to predict the anti-icing performance of such tubes and a test program was conducted to demonstrate actual performance of this system. Test data and analytical code results were in excellent agreement. Both indicate feasibility of using capillary tubes for surface heating as a means for composite engine structures to combat ice accumulation.

  20. Capillary Rise in Porous Media.

    PubMed

    Lago, Marcelo; Araujo, Mariela

    2001-02-01

    Capillary rise experiments were performed in columns filled with glass beads and Berea sandstones, using visual methods to register the advance of the water front. For the glass bead filled columns, early time data are well fitted by the Washburn equation. However, in the experiments, the advancing front exceeded the predicted equilibrium height. For large times, an algebraic behavior of the velocity of the front is observed (T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)). A model for studying the capillary pressure evolution in a regular assembly of spheres is proposed and developed. It is based on a quasi-static advance of the meniscus with a piston-like motion and allows us to estimate the hydraulic equilibrium height, with values very close to those obtained by fitting early time data to a Washburn equation. The change of regime is explained as a transition in the mechanism of advance of the meniscus. On the other hand, only the Washburn regime was observed for the sandstones. The front velocity was fitted to an algebraical form with an exponent close to 0.5, a value expected from the asymptotic limit of the Washburn equation. Copyright 2001 Academic Press. PMID:11161488

  1. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  2. 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.

  3. Electrostatic-spray ionization mass spectrometry.

    PubMed

    Qiao, Liang; Sartor, Romain; Gasilova, Natalia; Lu, Yu; Tobolkina, Elena; Liu, Baohong; Girault, Hubert H

    2012-09-01

    An electrostatic-spray ionization (ESTASI) method has been used for mass spectrometry (MS) analysis of samples deposited in or on an insulating substrate. The ionization is induced by a capacitive coupling between an electrode and the sample. In practice, a metallic electrode is placed close to but not in direct contact with the sample. Upon application of a high voltage pulse to the electrode, an electrostatic charging of the sample occurs leading to a bipolar spray pulse. When the voltage is positive, the bipolar spray pulse consists first of cations and then of anions. This method has been applied to a wide range of geometries to emit ions from samples in a silica capillary, in a disposable pipet tip, in a polymer microchannel, or from samples deposited as droplets on a polymer plate. Fractions from capillary electrophoresis were collected on a polymer plate for ESTASI MS analysis. PMID:22876737

  4. Quantitation of Leishmania lipophosphoglycan repeat units by capillary electrophoresis.

    PubMed

    Barron, Tamara L; Turco, Salvatore J

    2006-04-01

    The glycosylphosphatidylinositol (GPI)-anchored lipophosphoglycan (LPG) of Leishmania is the dominant cell surface glycoconjugate of these pathogenic parasites. LPG is structurally characterized by a series of phosphoglycan repeat units. Determining the number of repeat units per LPG molecule has proven difficult using current technologies, such as mass spectrometry. As an alternative method to quantitate the number of repeat units in LPG, a procedure based on capillary electrophoretic analysis of the proportion of mannose to 2,5-anhydromannose (derived from the nonacetylated glucosamine of the GPI anchor of LPG) was developed. The CE-based technique is sensitive and relatively rapid compared to GC-MS-based protocols. Its application was demonstrated in quantitating the number of LPG repeat units from several species of Leishmania as well as from two life-cycle stages of these organisms. PMID:16310310

  5. Capillary Movement in Granular Beds in Microgravity

    NASA Technical Reports Server (NTRS)

    Yendler, Boris S.; Bula, Ray J.; Kliss, Mark (Technical Monitor)

    1996-01-01

    Understanding the dynamics of capillary flow through unsaturated porous media is very important for the development of an effective water and nutrient delivery system for growing plants in microgravity and chemical engineering applications. Experiments were conducted on the Space Shuttle during the STS-63 mission using three experimental cuvettes called "Capillary Testbed-M." These experiments studied the effect of bead diameter on capillary flow by comparing the capillary flow in three different granular beds. It was observed that the speed of water propagation in the granular bed consisting of 1.5 mm diameter particles was less than that in the bed consisting of 1.0 mm. diameter particles. Such results contradict the existing theory of capillary water propagation in granular beds. It was found also that in microgravity water propagates independently in adjacent layers of a layered granular bed .

  6. Intracranial capillary hemangioma in an elderly patient

    PubMed Central

    Okamoto, Ai; Nakagawa, Ichiro; Matsuda, Ryosuke; Nishimura, Fumihiko; Motoyama, Yasushi; Park, Young-Su; Nakamura, Mitsutoshi; Nakase, Hiroyuki

    2015-01-01

    Background: Capillary hemangiomas are neoplasms involving skin and soft tissue in infants. These lesions rarely involved an intracranial space and reported age distribution ranges from infancy to middle age. We report an extremely rare case of rapidly rising intracranial capillary hemangioma in an elderly woman. Case Description: The 82-year-old woman presented with vomiting, reduced level of consciousness, and worsening mental state. Computed tomography showed a contrast-enhanced extra-axial lesion in the left frontal operculum, although no intracranial mass lesion was identifiable from magnetic resonance imaging taken 2 years earlier. Complete surgical excision was performed and histopathological examination diagnosed benign capillary hemangioma consisting of a variety of dilated capillary blood vessels lined by endothelial cells. Conclusion: This is the first description of rapid growth of an intracranial capillary hemangioma in an elderly woman. These lesions are exceedingly rare in the elderly population, but still show the capacity for rapid growth. Complete excision would prevent further recurrence. PMID:26664868

  7. Modeling capillary barriers in unsaturated fractured rock

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Shu; Zhang, W.; Pan, Lehua; Hinds, Jennifer; Bodvarsson, G. S.

    2002-11-01

    This work presents a series of numerical modeling studies that investigate the hydrogeologic conditions required to form capillary barriers and the effect that capillary barriers have on fluid flow and tracer transport processes in the unsaturated fractured rock of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. The modeling approach is based on a dual-continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. The numerical modeling results showed that effective capillary barriers can develop where both matrix and fracture capillary gradients tend to move water upward. Under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary barrier effects exist for diverting a significant amount of moisture flow through the relatively shallow Paintbrush nonwelded unit, with major faults observed at the site serving as major downward pathways for laterally diverted percolation fluxes. In addition, we used observed field liquid saturation and goechemical isotopic data to check model results and found consistent agreement.

  8. Capillary condensation onto titania (TiO2) nanoparticle agglomerates.

    PubMed

    Kim, Seonmin; Ehrman, Sheryl H

    2007-02-27

    A capillary condensation process was developed for the purpose of forming interconnections between nanoparticles at low temperatures. The process was performed in a temperature-controlled flow chamber on nanoparticle agglomerates deposited at submonolayer coverage on a transmission electron microscope grid. The partial pressure of the condensing species, tetraethyl orthosilicate, and the temperature of the chamber were adjusted in order to obtain the various saturation conditions for capillary condensation. The modified samples were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, BET surface area method, and scanning transmission electron microscopy with electron energy-loss spectrometry. Experimental results show that bridge-shaped layers were dominantly formed in the neck region between particles and were composed of amorphous silica. The analysis of TEM micrographs verified that the coverage of the layers is strongly dependent on the saturation ratio. Image analysis of TEM micrographs shows that this dependency is qualitatively in agreement with theoretical predictions based on the classical Kelvin equation for the specific geometries in our system. PMID:17243733

  9. Capillary-Based Multi Nanoelectrospray Emitters: Improvements in Ion Transmission Efficiency and Implementation with Capillary Reversed-Phase LC-ESI-MS

    SciTech Connect

    Kelly, Ryan T.; Page, Jason S.; Zhao, Rui; Qian, Weijun; Mottaz, Heather M.; Tang, Keqi; Smith, Richard D.

    2008-01-01

    We describe the coupling of liquid chromatography (LC) separations with mass spectrometry (MS) using nanoelectrospray ionization (nanoESI) multi-emitters. The array of 19 emitters reduced the flow rate delivered to each emitter, allowing the enhanced sensitivity that is characteristic of nanoESI to be extended to higher flow rate separations. The signal for peptides from spiked proteins in a human plasma tryptic digest increased 11-fold on average when the multi-emitters were employed, due to increased ionization efficiency and improved ion transfer efficiency through a newly designed heated multi-capillary MS inlet. Additionally, the LC peak signal-to-noise ratio increased ~7-fold when the multi-emitter configuration was used. The low dead volume of the emitter arrays preserved peak shape and resolution for robust capillary LC separations using total flow rates of 2-µL/min.

  10. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    2005-08-09

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

  11. The Capillary Fluidics of Espresso

    NASA Astrophysics Data System (ADS)

    Ott, Nathan; Wollman, Drew; Graf, John; Weislogel, Mark

    2014-11-01

    Espresso is enjoyed by tens of millions of people daily. The coffee is distinguished by a complex low density colloid of emulsified oils. Due to gravity, these oils rise to the surface forming a foam lid called the crema. In this work we present a variety of large length scale capillary fluidic effects for espresso in a gravity-free environment. Drop tower tests are performed to establish brief microgravity conditions under which spontaneous capillarity-driven behavior is observed. Because the variety of espresso drinks is extensive, specific property measurements are made to assess the effects of wetting and surface tension for `Italian' espresso, caffe latte, and caffe Americano. To some, the texture and aromatics of the crema play a critical role in the overall espresso experience. We show how in the low-g environment this may not be possible. We also suggest alternate methods for enjoying espresso aboard spacecraft. NASA NNX09AP66A, Glenn Research Center.

  12. Mass spectrometry

    SciTech Connect

    Burlingame, A.L.; Baillie, T.A.; Derrick, P.J.

    1986-04-01

    It is the intention of the review to bring together in one source the direction of major developments in mass spectrometry and to illustrate these by citing key contributions from both fundamental and applied research. The Review is intended to provide the reader with a sense of the main currents, their breadth and depth, and probable future directions. It is also intended to provide the reader with a glimpse of the diverse discoveries and results that underpin the eventual development of new methods and instruments - the keys to obtaining new insights in all the physical, chemical, and biological sciences which depend on mass spectrometry at various levels of sophistication. Focal points for future interdisciplinary synergism might be selective quantitative derivatization of large peptides, which would convey properties that direct fragmentation providing specific sequence information, or optimization of LCMS for biooligomer sequencing and mixture analysis, or the perfect way to control or enhance the internal energy of ions of any size, or many others. 1669 references.

  13. Geometry of the capillary net in human hearts.

    PubMed

    Rakusan, K; Cicutti, N; Spatenka, J; Samánek, M

    1997-01-01

    The geometry of the coronary capillary bed in human hearts was studied using samples obtained during cardiac surgery of children operated for tetralogy of Fallot and samples from fresh normal hearts used for valve harvesting. The results revealed a similar coronary capillary density and heterogeneity of capillary spacing in samples from both groups. A double-staining method was used to distinguish between capillary segments close to the feeding arteriole (proximal capillaries) and segments distant from the arteriole (distal capillaries). In both groups of hearts, capillary segment length was consistently shorter on the venular than the arteriolar portion of the capillary. Similarly, capillary domain areas were also smaller and the resulting capillary supply unit was smaller along venular portions compared to arteriolar regions of the capillary bed. This distinctive geometry would provide advantageous geometric conditions for tissue oxygen supply. PMID:9176723

  14. Towards new applications using capillary waveguides

    PubMed Central

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N.; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-01-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  15. Towards new applications using capillary waveguides.

    PubMed

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-12-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  16. Evaporation dynamics of femtoliter water capillary bridges

    NASA Astrophysics Data System (ADS)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Kim, Jung Gu; Weon, Byung Mook

    2015-11-01

    Capillary bridges are usually formed by a small liquid volume in confined space between two solid surfaces and particularly they have lower internal pressure than 1 atm at femtoliter scales. Femtoliter capillary bridges exhibit rapid evaporation rates. To quantify detailed evaporation kinetics of femtoliter bridges, we present a feasible protocol to directly visualize femtoliter water bridges that evaporate in still air between a microsphere and a flat substrate by utilizing transmission X-ray microscopy. Precise measurements of evaporation kinetics for water bridges indicate that lower water pressure than 1 atm can significantly decelerate evaporation by suppression of vapor diffusion. This finding would provide a consensus to understand evaporation of ultrasmall capillary bridges.

  17. Arrested segregative phase separation in capillary tubes.

    PubMed

    Tromp, R Hans; Lindhoud, Saskia

    2006-09-01

    Phase separation in a capillary tube with one of the phases fully wetting the capillary wall is arrested when the typical size of the phase domains reaches the value of the diameter of the tube. The arrested state consists of an alternating sequence of concave-capped and convex-capped cylindrical domains, called "plugs," "bridges," or "lenses," of wetting and nonwetting phase, respectively. A description of this arrested plug state for an aqueous mixture of two polymer solutions is the subject of this work. A phase separating system consisting of two incompatible polymers dissolved in water was studied. The phase volume ratio was close to unity. The initial state from which plugs evolve is characterized by droplets of wetting phase in a continuous nonwetting phase. Experiments show the formation of plugs by a pathway that differs from the theoretically well-described instabilities in the thickness of a fluid thread inside a confined fluid cylinder. Plugs appear to form after the wetting layer (the confined fluid cylinder) has become unstable after merging of droplet with the wetting layer. The relative density of the phases could be set by the addition of salt, enabling density matching. As a consequence, the capillary length can in principle be made infinitely large and the Bond number (which represents the force of gravity relative to the capillary force) zero, without considerably changing the interfacial tension. Using the possibility of density matching, the relations among capillary length and capillary diameter on the one hand, and the presence of plugs and their average size on the other were studied. It was found that stable plugs are present when the capillary radius does not exceed a certain value, which is probably smaller than the capillary length. However, the average plug size is independent of capillary length. At constant capillary length, average plug size was found to scale with the capillary diameter to a power 1.3, significantly higher than the

  18. Cytokine Analysis by Immunoaffinity Capillary Electrophoresis

    PubMed Central

    Mendonca, Mark; Kalish, Heather

    2014-01-01

    Immunoaffinity capillary electrophoresis (ICE) is a powerful tool used to detect and quantify target proteins of interest in complex biological fluids. The target analyte is captured and bound to antibodies immobilized onto the wall of a capillary, labeled in situ with a fluorescent dye, eluted and detected online using laser-induced fluorescence following electrophoretic separation. Here, we illustrate how to construct an immunoaffinity capillary and utilize it to run ICE in order to capture and quantify target cytokines and chemokines from a clinical sample. PMID:22976107

  19. Micromechanism linear actuator with capillary force sealing

    DOEpatents

    Sniegowski, Jeffry J.

    1997-01-01

    A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.

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

    PubMed

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

    2016-09-01

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

  1. Dermal nitrate: an old marker of firearm discharge revisited with capillary electrophoresis.

    PubMed

    Tagliaro, Franco; Bortolotti, Federica; Manetto, Giulia; Pascali, Vincenzo L; Marigo, Mario

    2002-01-01

    The present work describes a capillary electrophoretic method for nitrite and nitrate determination to be used as a screening tool for investigating the residues of firearm discharge. The use of capillary electrophoresis allowed the rapid determination of nitrite and nitrate, which are major inorganic components of gunshot residues, offering a quantitative and selective alternative to the traditional paraffin test (dermal nitrate test). The method is simpler, cheaper, and faster than the modern approaches to gunshot residue analysis based on the determination of barium, lead and antimony by using flameless absorption spectrometry, inductively coupled plasma-mass spectrometry (ICP-MS), or scanning electron microscopy. The analysis was carried out in a bare fused-silica capillary (75 microm inner diameter) with a 100 mM borate buffer (pH 9.24). The detection was by UV absorption at 214 nm. Separation took place under reversed voltage of 15 kV. Bromide was used as the internal standard. Sensitivity was about 1 mM for both nitrite and nitrate. Reproducibility (intraday and day-to-day) was also good with relative standard deviations (RSDs) < 1.0% for relative migration times and < 4.5% for peak areas in both standard solutions and real matrix. Hair and skin samples from a victim shot in the head were successfully analyzed for the presence of nitrite and nitrate. PMID:11840536

  2. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  3. ISS Update: Capillary Flow Experiments-2

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Dr. Mark Weislogel, Principal Investigator for the Capillary Flow Experiments-2 (CFE), from the Portland State University in Oregon. The CFE i...

  4. Capillary Optics generate stronger X-rays

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA scientist, in the Space Sciences lab at Marshall, works with capillary optics that generate more intense X-rays than conventional sources. This capability is useful in studying the structure of important proteins.

  5. Suppressed conductometric capillary electrophoresis separation systems

    SciTech Connect

    Dasgupta, P.K.; Bao, L. )

    1993-04-15

    A tubular cation-exchange membrane is installed at the end of a 60-cm-long 75-[mu]m-bore fused-silica capillary. A static dilute acid regenerant solution surrounds the membranes that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerant solution grounded, effective suppression of electrolytes such as solutions of alkalic metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 10--20 [mu]g/L range for a variety of anions; a typical separation requires 15 min. Applicability to a variety of real samples is demonstrated. 26 refs., 10 figs.

  6. Capillary electrochromatography using fibers as stationary phases.

    PubMed

    Jinno, K; Watanabe, H; Saito, Y; Takeichi, T

    2001-10-01

    Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method. PMID:11669512

  7. CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS

    EPA Science Inventory

    The electrophoretic behavior of bensulfuron Me, sulfometuron Me, nicosulfuron (Accent), chlorimuron Et, thifensulfuron Me (Harmony), metsulfuron Me, and chlorsulfuron was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditio...

  8. Characterising Microstructured Materials Using a Capillary Rheometer

    NASA Astrophysics Data System (ADS)

    Hicks, Christopher I.; See, Howard; Arabo, Emad Y. M.

    2008-07-01

    A parallel plate and capillary rheometer have been used to rheologically characterize an Australian hard wheat flour-water dough over an extensive range of shear rates (10-3-104 s-1). Torsional measurements showed that the shear viscosity of dough increased with strain to a maximum value then decreased, suggesting a breakdown of the dough structure. This was consistent with other published data on doughs. Capillary experiments revealed the shear thinning behavior of dough, which was described by a power-law model. The wall slip behavior of dough was examined, revealing a critical shear stress at which slip occurs for a 1 mm diameter capillary. The capillary data was best linked to the torsional data at low strain values (˜0.1) as expected given the nature of sampling in the two rheometers.

  9. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis

    PubMed Central

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

    2014-01-01

    The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis. PMID:25126117

  10. Capillary Movement in Substrates in Microgravity

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Duffie, N. A.

    1996-01-01

    A more complete understanding of the dynamics of capillary flow through an unsaturated porous medium would be useful for a number of space and terrestrial applications. Knowledge of capillary migration of liquids in granular beds in microgravity would significantly enhance the development and understanding of how a matrix based nutrient delivery system for the growth of plants would function in a microgravity environment. Thus, such information is of interest from the theoretical as well as practical point of view.

  11. DNA Sequencing by Capillary Electrophoresis

    PubMed Central

    Karger, Barry L.; Guttman, Andras

    2009-01-01

    Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA sequencing methods have evolved from the labor intensive slab gel electrophoresis, through automated multicapillary electrophoresis systems using fluorophore labeling with multispectral imaging, to the “next generation” technologies of cyclic array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes was only possible by the advent of modern sequencing technologies that was a result of step by step advances with a contribution of academics, medical personnel and instrument companies. While next generation sequencing is moving ahead at break-neck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of capillary electrophoresis in DNA sequencing based in part of several of our articles in this journal. PMID:19517496

  12. Nonlinear waves in capillary electrophoresis

    PubMed Central

    Ghosal, Sandip; Chen, Zhen

    2011-01-01

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

  13. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1996-10-22

    A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

  14. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1996-01-01

    A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

  15. Unexpected surface chemistry in capillaries for electrophoresis.

    PubMed

    Kaupp, S; Bubert, H; Baur, L; Nelson, G; Wätzig, H

    2000-10-13

    Good and reproducible capillary quality is needed to develop robust methods and to facilitate method transfer in CE. Physical surface defects no longer play a major role in variability of fused-silica capillaries. Nevertheless, problems are frequently being reported when buffers in the pH range between 4 and 7 are used. Thus the surface chemistry has been studied by X-ray photoelectron spectroscopy. Silicon-carbon bindings have been found on inner capillary surfaces for electrophoresis. This binding type is not completely removed by pre-conditioning with 1 M NaOH for 30 min. This corresponds to the result, that capillaries provide more stable migration times, especially in the pH range 4-7, when they are pre-conditioned for longer than 1 h. The origin of this Si-C bond is still not quite clear. They could be caused by graphite which is used during the fabrication of the raw cylinders prior to capillary drawing. Further investigations are intended in order to understand if there are any differences in surface carbon content from batch to batch and if this can influence experimental results in CE. A better understanding of the surface chemistry should not only improve robustness in CE, but also help to facilitate and accelerate capillary pre-conditioning and rinsing procedures to remove strongly adsorbed analytes or matrices. PMID:11100849

  16. Cell adhesion during bullet motion in capillaries.

    PubMed

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis. PMID:27261363

  17. One-step multiple component isolation from the oil of Crinitaria tatarica (Less) Sojak by preparative capillary gas chromatography with characterization by spectroscopic and spectrometric techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the present work multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by Preparative Capillary Gas Chromatography (PCGC) with characterization by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have been carried out. Gas chromatography (GC-FID) ...

  18. Capillary GC analysis of compounds leached into parenteral solutions packaged in plastic bags

    SciTech Connect

    Snell, R.P. )

    1989-09-01

    A number of investigators have reported finding the plasticizer di(2-ethylhexyl)phthalate in plasma, urine, and parenteral solutions. These findings have been associated with the use of polyvinyl chloride packaging materials. Capillary gas chromatography--mass spectrometry, packed column gas chromatography, and high-performance liquid chromatography were used for the analyses. The screening procedure described herein accurately and quantitatively analyzes the plasticizers di(2-ethylhexyl)phthalate and dibutylphthalate and some of the degradation products plus 2,6-di-tert-butyl-p-cresol and cyclohexanone. Liquid--liquid extraction followed by capillary gas chromatography is used. Linear regression analysis of standard solutions gives correlation coefficients from 0.99963 to 0.99989 for six compounds. Recoveries for these compounds vary from 84.9% to 114% with relative standard deviations ranging from 2.51% to 6.33%.

  19. A capillary holder for scanning detection of capillary isoelectric focusing with laser-induced fluorescence.

    PubMed

    Takahashi, Katsuyoshi; Maruo, Yuji; Kitamori, Takehiko; Shimura, Kiyohito

    2009-02-01

    A holder for a 12 cm long capillary was designed for scanning LIF detection of CIEF. The polyimide coat of a fused-silica capillary has been removed, and 1.5 mm diameter flanges have been attached near both ends. The holder is fixed on the stage of a fluorescence microscope via a translational stage, and a capillary guide is directly fixed on the microscope stage. The guide has a groove and a pressure plate for the capillary to slide in. The holder has two pulling plates with slits of 1 mm to accept the capillary just inside the flanges. The slits and the groove of the guide have been aligned. The motion of the translational stage brings the pulling plate into contact with the flange at the pulled side, and slides the capillary through the guide. The other end of the capillary is free and produces no strain on the capillary. When the motion of the stage is reversed, an unstrained contact is achieved at the other end. The baseline noise from scanning was only 50% larger than that without scanning. The fluorescence-signal variation during scanning was about 4% of the total signal, which was about twice that without scanning. PMID:19142915

  20. Gold nanoparticle-coated capillaries for protein and peptide analysis on open-tubular capillary electrochromatography.

    PubMed

    Hamer, Mariana; Yone, Angel; Rezzano, Irene

    2012-01-01

    We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary. PMID:22222978

  1. Critical Velocities in Open Capillary Flow

    NASA Technical Reports Server (NTRS)

    Dreyer, Michael; Langbein, Dieter; Rath, Hans J.

    1996-01-01

    This paper describes the proposed research program on open capillary flow and the preliminary work performed theoretically and in drop tower experiments. The work focuses on the fundamental physical understanding of the flow through capillary bound geometries, where the circumference of the cross section of the flow path contains free surfaces. Examples for such a flow configuration are capillary vanes in surface tension tanks, flow along edges and corners and flow through liquid bridges. The geometries may be classified by their cross section areas, wetted circumferences and the radii of curvature of the free surfaces. In the streaming float zone the flow path is bound by a free surface only. The ribbon vane is a model for vane types used in surface tension tanks, where a structure in proximity to the tank wall forms a capillary gap. A groove is used in heat pipes for the transportation of the condensed working fluid to the heat source and a wedge may occur in a spaceborne experiment where fluid has to be transported by the means of surface tension. The research objectives are the determination of the maximum volume flux, the observation of the free surfaces and the liquid flow inside the flow path as well as the evaluation of the limiting capillary wave speed. The restriction of the maximum volume flux is due to convective forces (flow velocity exceeding the capillary wave speed) and/or viscous forces, i.e. the viscous head loss along the flow path must be compensated by the capillary pressure due to the curved free surface. Exceeding the maximum volume flux leads to the choking of the flow path, thus the free surface collapses and.gas ingestion occurs at the outlet. The means are ground-based experimental work with plateau tanks and in a drop tower, a sounding rocket flight, and theoretical analysis with integral balances as well as full three dimensional CFD solutions for flow with free surfaces.

  2. Use of capillary electrophoresis and indirect detection to quantitate in-capillary enzyme-catalyzed microreactions.

    PubMed

    Zhang, Y; el-Maghrabi, M R; Gomez, F A

    2000-04-01

    The use of capillary electrophoresis and indirect detection to quantify reaction products of in-capillary enzyme-catalyzed microreactions is described. Migrating in a capillary under conditions of electrophoresis, plugs of enzyme and substrate are injected and allowed to react. Capillary electrophoresis is subsequently used to measure the extent of reaction. This technique is demonstrated using two model systems: the conversion of fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate by fructose-biphosphate aldolase (ALD, EC 4.1.2.13), and the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate by fructose-1,6-bisphospatase (FBPase, EC 3.1.3.11). These procedures expand the use of the capillary as a microreactor and offer a new approach to analyzing enzyme-mediated reactions. PMID:10892022

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

    SciTech Connect

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

    1992-01-01

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

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

    SciTech Connect

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

    2006-10-01

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

  5. Simulations of Slow Capillary Discharges for BELLA

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey; Colella, Phillip; Geddes, Cameron; Esarey, Eric; Leemans, Wim; Mittelberger, Daniel; Bulanov, Stepan; Stoltz, Peter

    2010-11-01

    Capillary plasma channels are used to extend the propagation distance of relativistically intense laser pulses for laser plasma acceleration [1], and axial density modulation has been used to stabilize injection at LBNL. Channel formation is a complex process in which a gas is ionized via a slow discharge, and subsequently stabilized by a capillary wall via heat transfer. Here we describe simulations using a multi-species, 2-temperature plasma model to study the effects of electrical and thermal conduction, species diffusion, and externally-applied magnetic fields on this process for present experiments and to plan m-scale capillaries at reduced densities for the BELLA laser. These radially-symmetric simulations, performed with the 1D cylindrical code SCYLLA from LBNL, resolve the radial behavior of the plasma within the capillary but do not accurately describe dynamics near the ends of the capillary or near gas feed slots or jets. To understand these regions, we present results of simulations using the 3-dimensional hydrodynamics code HYDRA from Lawrence Livermore National Laboratory. We discuss work in progress on a multi-dimensional plasma model that leverages results from these simulations. References: [1] W. Leemans et al., Nat. Phys. 2, 696 (2006)

  6. Case report of lumbar intradural capillary hemangioma

    PubMed Central

    Unnithan, Ajaya Kumar Ayyappan; Joseph, T. P.; Gautam, Amol; Shymole, V.

    2016-01-01

    Background: Capillary hemangioma is a rare tumor in spinal intradural location. Despite the rarity, early recognition is important because of the risk of hemorrhage. This is a case report of a woman who had capillary hemangioma of cauda equina. Case Description: A 54 -year-old woman presented with a low backache, radiating to the left leg for 2 months. She had left extensor hallucis weakness, sensory impairment in left L5 dermatome, and mild tenderness in lower lumbar spine. Magnetic resonance imaging (MRI) LS spine showed L4/5 intradural tumor, completely occluding canal in myelogram, enhancing with contrast, s/o benign nerve sheath tumor. L4 laminectomy was done. Reddish tumor was seen originating from a single root. It was removed preserving the root. Postoperatively, she was relieved of symptoms. MRI showed no residue. Histopathology showed lobular proliferation of capillary-sized blood vessels and elongated spindle cells. Immunohistochemistry showed CD34 positivity in endothelial cell lining of blood vessel and smooth muscle actin positivity in blood vessel muscle cells. HPR-capillary hemangioma. Conclusion: Although rare, capillary hemangioma should be in the differential diagnosis of intradural tumors. It closely mimics nerve sheath tumor. PMID:27069745

  7. Passive Reactor Cooling Using Capillary Porous Wick

    SciTech Connect

    Miller, Christopher G.; Lin, Thomas F.

    2006-07-01

    Long-term reliability of actively pumped cooling systems is a concern in space-based nuclear reactors. Capillary-driven passive cooling systems are being considered as an alternative to gravity-driven systems. The high surface tension of liquid lithium makes it attractive as the coolant in a capillary-driven cooling system. A system has been conceived in which the fuel rod of a reactor is surrounded by a concentric wick through which liquid lithium flows to provide cooling under normal and emergency operating conditions. Unheated wicking experiments at three pressures using four layered screen mesh wicks of different porosities and three relatively high surface tension fluids have been conducted to gain insight into capillary phenomena for such a capillary cooling system. All fluids tested demonstrated wicking ability in each of the wick structures for all pressures, and wicking ability for each fluid increased with decreasing wick pore size. An externally heated wicking experiment with liquid lithium as the wicking fluid was also conducted. In addition to wicking experiments, a heater rod is under development to simulate the fuel rod of a space based nuclear reactor by providing a heat flux of up to 110 kW/m{sup 2}. Testing of this heater rod has shown its ability to undergo repeated cycling from below 533 K to over 1255 K without failure. This heater rod will be integrated into lithium wicking experiments to provide more realistic simulation of the proposed capillary-driven space nuclear reactor cooling system. (authors)

  8. Synthetic Capillaries to Control Microscopic Blood Flow

    PubMed Central

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  9. Capillary effects on floating cylindrical particles

    NASA Astrophysics Data System (ADS)

    Dixit, Harish N.; Homsy, G. M.

    2012-12-01

    In this study, we develop a systematic perturbation procedure in the small parameter, B1/2, where B is the Bond number, to study capillary effects on small cylindrical particles at interfaces. Such a framework allows us to address many problems involving particles on flat and curved interfaces. In particular, we address four specific problems: (i) capillary attraction between cylinders on flat interface, in which we recover the classical approximate result of Nicolson ["The interaction between floating particles," Proc. Cambridge Philos. Soc. 45, 288-295 (1949), 10.1017/S0305004100024841], thus putting it on a rational basis; (ii) capillary attraction and aggregation for an infinite array of cylinders arranged on a periodic lattice, where we show that the resulting Gibbs elasticity obtained for an array can be significantly larger than the two cylinder case; (iii) capillary force on a cylinder floating on an arbitrary curved interface, where we show that in the absence of gravity, the cylinder experiences a lateral force which is proportional to the gradient of curvature; and (iv) capillary attraction between two cylinders floating on an arbitrary curved interface. The present perturbation procedure does not require any restrictions on the nature of curvature of the background interface and can be extended to other geometries.

  10. EUV radiation from nitrogen capillary discharge

    NASA Astrophysics Data System (ADS)

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav

    2014-08-01

    In the last decade EUV sources attract interest from researchers over the world. One of the main motivations is EUV lithography, which could lead to further miniaturization in electronics. Nitrogen recombination laser at wavelength of 13.4 nm based on capillary discharge Z-pinch configuration could be used in experiments with testing of resolution of photoresist for EUV lithography (close to wavelength of 13.5 nm Si/Mo multilayer mirrors have a high reflectivity at normal incidence angles). In this work, pinching of nitrogen-filled capillary discharge is studied for the development of EUV laser, which is based on recombination pumping scheme. The goal of this study is achieving the required plasma conditions using a capillary discharge Z-pinch apparatus. In experiments with nitrogen, the capillary length was shortened from 232 mm to 90 mm and current quarter-period was changed from 60 ns to 50 ns in contrast with early experiments with Ne-like argon laser. EUV radiation from capillary discharge was registered by X-ray vacuum diode for different pressure, amplitude and duration of pre-pulse and charging voltage of the Marx generator.

  11. Synthetic Capillaries to Control Microscopic Blood Flow

    NASA Astrophysics Data System (ADS)

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-02-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function.

  12. Synthetic Capillaries to Control Microscopic Blood Flow.

    PubMed

    Sarveswaran, K; Kurz, V; Dong, Z; Tanaka, T; Penny, S; Timp, G

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using "live cell lithography"(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision-no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  13. Capillary xray compressor: principle versus practice

    NASA Astrophysics Data System (ADS)

    Brewe, Dale L.; Heald, Steve M.; Barg, Bill; Brown, Frederick C.; Kim, Kyungha H.; Stern, Edward A.

    1995-09-01

    Guiding x rays down the inside of tapered capillaries is a means to increase the flux density of x rays from synchrotron light sources without some of the disadvantages inherent in other techniques. We have demonstrated that a process based on techniques for fabrication of glass fibers may be used to produce tapered capillaries with inlet diameters on the order of 150 micrometers or more, and outlets on the order of 1 micrometer or less. We present a description of the capillary fabrication and results of tests of the performance of several capillaries, along with a comparison with calculations of performance. We also summarize refinements to the fabrication process that will provide additional improvements. The transmission of x rays from linear capillaries with inlet diameters of approximately 150 micrometers and outlet diameters of 1.3 - 1.4 micrometer is on the order of 2%, with corresponding intensity gains of up to 274. Initial results indicate that the capability exists for producing convex profiles necessary for optimal transmission. Calculated and measured transmission efficiencies are in fairly good agreement, leading to the expectation that efficiencies predicted by calculations to be attainable from optimal profiles are a realistic goal, given the ability to manufacture these profiles.

  14. Capillary self-assembly of floating bodies

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan; Thompson, Paul; Bush, John

    2007-11-01

    We study the self-assembly of bodies supported on the water surface by surface tension. Attractive and repulsive capillary forces exist between menisci of, respectively, the same and opposite signs. In nature, floating objects (e.g. mosquito larvae) thus interact through capillary forces to form coherent packings on the water surface. We here present the results of an experimental investigation of such capillary pattern formation. Thin elliptical metal sheets were designed to have variable shape, flexibility and mass distribution. On the water surface, mono-, bi-, or tri-polar menisci could thus be achieved. The influence of the form of the menisci on the packings arising from the interaction of multiple floaters is explored. Biological applications are discussed.

  15. Deformation of vesicles flowing through capillaries

    NASA Astrophysics Data System (ADS)

    Vitkova, V.; Mader, M.; Podgorski, T.

    2004-11-01

    The flow of giant lipid vesicles through cylindrical capillaries is experimentally investigated. Vesicles are deflated with reduced volumes between 0.8 and 1, corresponding to prolate spheroidal equilibrium shapes. Both interior and exterior fluids are sugar solutions with viscosities close to 10-3 Pa s. Vesicles are aspirated into a capillary tube with a diameter close to the vesicle size and a constant flow rate is imposed. Significant deformation of the membrane occurs and increases when the velocity, confinement or deflation of the vesicle are increased. The mobility of vesicles, defined as the ratio of their velocity to the average velocity of the fluid is a decreasing function of confinement. Our experimental system provides a controllable and flexible tool to investigate deformability effects responsible for crucial aspects of blood rheology in capillaries.

  16. Prediction of tilted capillary barrier performance

    SciTech Connect

    Webb, S.W.; McCord, J.T.; Dwyer, S.F.

    1997-04-01

    Capillary barriers, consisting of tilted fine-over-coarse layers under unsaturated conditions, have been suggested as landfill covers to divert water infiltration away from sensitive underground regions, especially for arid and semi-arid regions. The Hydrological Evaluation of Landfill Performance (HELP) computer code is an evaluation tool for landfill covers used by designers and regulators. HELP is a quasi-two-dimensional model that predicts moisture movement into and through the underground soil and waste layers. Processes modeled within HELP include precipitation, runoff, evapotranspiration, unsaturated vertical drainage, saturated lateral drainage, and leakage through liners. Unfortunately, multidimensional unsaturated flow phenomena that are necessary for evaluating tilted capillary barriers are not included in HELP. Differences between the predictions of the HELP and those from a multidimensional unsaturated flow code are presented to assess the two different approaches. Comparisons are presented for the landfill covers including capillary barrier configurations at the Alternative Landfill Cover Demonstration (ALCD) being conducted at Sandia.

  17. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Y.

    1994-07-27

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

  18. Mach-like capillary-gravity wakes.

    PubMed

    Moisy, Frédéric; Rabaud, Marc

    2014-08-01

    We determine experimentally the angle α of maximum wave amplitude in the far-field wake behind a vertical surface-piercing cylinder translated at constant velocity U for Bond numbers Bo(D)=D/λ(c) ranging between 0.1 and 4.2, where D is the cylinder diameter and λ(c) the capillary length. In all cases the wake angle is found to follow a Mach-like law at large velocity, α∼U(-1), but with different prefactors depending on the value of Bo(D). For small Bo(D) (large capillary effects), the wake angle approximately follows the law α≃c(g,min)/U, where c(g,min) is the minimum group velocity of capillary-gravity waves. For larger Bo(D) (weak capillary effects), we recover a law α∼√[gD]/U similar to that found for ship wakes at large velocity [Rabaud and Moisy, Phys. Rev. Lett. 110, 214503 (2013)]. Using the general property of dispersive waves that the characteristic wavelength of the wave packet emitted by a disturbance is of order of the disturbance size, we propose a simple model that describes the transition between these two Mach-like regimes as the Bond number is varied. We show that the new capillary law α≃c(g,min)/U originates from the presence of a capillary cusp angle (distinct from the usual gravity cusp angle), along which the energy radiated by the disturbance accumulates for Bond numbers of order of unity. This model, complemented by numerical simulations of the surface elevation induced by a moving Gaussian pressure disturbance, is in qualitative agreement with experimental measurements. PMID:25215822

  19. Control of electroosmosis in coated quartz capillaries

    NASA Technical Reports Server (NTRS)

    Herren, Blair J.; Van Alstine, James; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1987-01-01

    The effectiveness of various coatings for controlling the electroosmotic fluid flow that hinders electrophoretic processes is studied using analytical particle microelectrophoresis. The mobilities of 2-micron diameter glass and polystyrene latex spheres (exhibiting both negative and zero effective surface charge) were measured in 2-mm diameter quartz capillaries filled with NaCl solutions within the 3.5-7.8 pH range. It is found that capillary inner surface coatings using 5000 molecular weight (or higher) poly(ethylene glycol): significantly reduced electroosmosis within the selected pH range, were stable for long time periods, and appeared to be more effective than dextran, methylcellulose, or silane coatings.

  20. A lymph nodal capillary-cavernous hemangioma.

    PubMed

    Dellachà, A; Fulcheri, E; Campisi, C

    1999-09-01

    A capillary-cavernous hemangioma in an obturator lymph node was found incidentally in a 64 year-old woman who had undergone unilateral salpingo-oophorectomy and lymphadenectomy for an ovarian neoplasm. Vascular tumors of lymph nodes are briefly reviewed including eight previously described nodal capillary-cavernous hemangiomas. The association with other splanchnic hemangiomas is pointed out and the likelihood that the lesion is a hamartoma rather than a true neoplasm is addressed. Despite its rarity, this entity needs to be recognized by lymphologists who image lymph nodes by lymphangiography as well as by lymph nodal pathologists. PMID:10494525

  1. Use of Plastic Capillaries for Macromolecular Crystallization

    NASA Technical Reports Server (NTRS)

    Potter, Rachel R.; Hong, Young-Soo; Ciszak, Ewa M.

    2003-01-01

    Methods of crystallization of biomolecules in plastic capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods used batch, free-interface liquid- liquid diffusion alone, or a combination with vapor diffusion. Results demonstrated growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as protein studied in our laboratory such dihydrolipoamide dehydrogenase. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until the desired time of activation of crystallization experiments.

  2. Capillary origami and superhydrophobic membrane surfaces

    NASA Astrophysics Data System (ADS)

    Geraldi, N. R.; Ouali, F. F.; Morris, R. H.; McHale, G.; Newton, M. I.

    2013-05-01

    Capillary origami uses surface tension to fold and shape solid films and membranes into three-dimensional structures. It uses the fact that solid surfaces, no matter how hydrophobic, will tend to adhere to and wrap around the surface of a liquid. In this work, we report that a superhydrophobic coating can be created, which can completely suppress wrapping as a contacting water droplet evaporates. We also show that using a wetting azeotropic solution of allyl alcohol, which penetrates the surface features, can enhance liquid adhesion and create more powerful Capillary Origami. These findings create the possibility of selectively shaping membrane substrates.

  3. Laser absorption waves in metallic capillaries

    NASA Astrophysics Data System (ADS)

    Anisimov, V. N.; Arutiunian, R. V.; Bol'Shov, L. A.; Kanevskii, M. F.; Kondrashov, V. V.

    1987-07-01

    The propagation of laser absorption waves in metallic capillaries was studied experimentally and numerically during pulsed exposure to CO2 laser radiation. The dependence of the plasma front propagation rate on the initial air pressure in the capillary is determined. In a broad range of parameters, the formation time of the optically opaque plasma layer is governed by the total laser pulse energy from the beginning of the exposure to the instant screening appears, and is weakly dependent on the pulse shape and gas pressure.

  4. Spectrometer capillary vessel and method of making same

    DOEpatents

    Linehan, John C.; Yonker, Clement R.; Zemanian, Thomas S.; Franz, James A.

    1995-01-01

    The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube.

  5. Spectrometer capillary vessel and method of making same

    DOEpatents

    Linehan, J.C.; Yonker, C.R.; Zemanian, T.S.; Franz, J.A.

    1995-11-21

    The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube. 13 figs.

  6. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, Harbans S.; Quesada, Mark A.; Studier, F. William

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis.

  7. Application of CHESS single-bounce capillaries at synchrotron beamlines

    NASA Astrophysics Data System (ADS)

    Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.

    2014-03-01

    Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

  8. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, H.S.; Quesada, M.A.; Studier, F.W.

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis. 35 figs.

  9. Cyclodextrin-Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications.

    PubMed

    Adly, Frady G; Antwi, Nana Yaa; Ghanem, Ashraf

    2016-02-01

    In this review, the recently reported approaches for the preparation of cyclodextrin-functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97-109, 2016. © 2015 Wiley Periodicals, Inc. PMID:26563470

  10. Capillary migration of microdisks on curved interfaces.

    PubMed

    Yao, Lu; Sharifi-Mood, Nima; Liu, Iris B; Stebe, Kathleen J

    2015-07-01

    The capillary energy landscape for particles on curved fluid interfaces is strongly influenced by the particle wetting conditions. Contact line pinning has now been widely reported for colloidal particles, but its implications in capillary interactions have not been addressed. Here, we present experiment and analysis for disks with pinned contact lines on curved fluid interfaces. In experiment, we study microdisk migration on a host interface with zero mean curvature; the microdisks have contact lines pinned at their sharp edges and are sufficiently small that gravitational effects are negligible. The disks migrate away from planar regions toward regions of steep curvature with capillary energies inferred from the dissipation along particle trajectories which are linear in the deviatoric curvature. We derive the curvature capillary energy for an interface with arbitrary curvature, and discuss each contribution to the expression. By adsorbing to a curved interface, a particle eliminates a patch of fluid interface and perturbs the surrounding interface shape. Analysis predicts that perfectly smooth, circular disks do not migrate, and that nanometric deviations from a planar circular, contact line, like those around a weakly roughened planar disk, will drive migration with linear dependence on deviatoric curvature, in agreement with experiment. PMID:25618486

  11. Design criteria for SW-205 capillary system

    SciTech Connect

    Lyons, W.J.

    1989-04-01

    This design criteria covers the converting of the SW-250 Capillary System from fumehood manual operation to sealed glovebox automated operation. The design criteria contains general guidelines and includes drawings reflecting a similar installation at another site. Topics include purpose and physical description, architectural-engineering requirements, reference document, electrical, fire protection, occupational safety and health, quality assurance, and security.

  12. DNA ADDUCT RESEARCH WITH CAPILLARY ELECTROPHORESIS

    EPA Science Inventory

    DNA's central importance in all biological systems dictates a wide variety of DNA-related research. or much of this research, the utilization of capillary electrophoresis (CE) can be of significant advantage. pen-tube CE yields excellent separations of DNA components, which can b...

  13. Analytical biotechnology: Capillary electrophoresis and chromatography

    SciTech Connect

    Horvath, C.; Nikelly, J.G.

    1990-01-01

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

  14. Numerical simulations of capillary barrier field tests

    SciTech Connect

    Morris, C.E.; Stormont, J.C.

    1997-12-31

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.

  15. Microfluidic Breadboard Approach to Capillary Electrophoresis.

    PubMed

    Koenka, Israel Joel; Sáiz, Jorge; Rempel, Paul; Hauser, Peter C

    2016-04-01

    A breadboard approach for electrophoretic separations with contactless conductivity detection is presented. This is based on miniature off-the-shelf components such as syringe pumps, valves, and pressure controllers which could be set up in a very compact overall arrangement. It has a high flexibility for different tasks at hand, and the common operations of hydrodynamic injection and capillary flushing are automated. For demonstration of the versatility of the proposition, several very diverse configurations and modes of electrophoresis were successfully implemented, namely, standard capillary zone electrophoresis, pressure assisted zone electrophoresis, the simultaneous separation of cations and anions by dual-capillary zone electrophoresis, the separation of cationic amino acids by isotachophoresis, as well as the separation of small carboxylic acids by gradient elution moving boundary electrophoresis. The system also allows fast separations, as demonstrated by the analysis of six inorganic cations within 35 s. The approach addresses respective limitations of either conventional capillary electrophoresis instruments as well as electrophoretic lab-on-chip devices, while maintaining a performance in terms of detection limits and reproducibility comparable to standard instrumentation. PMID:26926522

  16. Macroscopic theory for capillary-pressure hysteresis.

    PubMed

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

    2015-03-01

    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials. PMID:25646688

  17. Imbibition of ``Open Capillary'': Fundamentals and Applications

    NASA Astrophysics Data System (ADS)

    Tani, Marie; Kawano, Ryuji; Kamiya, Koki; Okumura, Ko

    2015-11-01

    Control or transportation of small amount of liquid is one of the most important issues in various contexts including medical sciences or pharmaceutical industries to fuel delivery. We studied imbibition of ``open capillary'' both experimentally and theoretically, and found simple scaling laws for both statics and dynamics of the imbibition, similarly as that of imbibition of capillary tubes. Furthermore, we revealed the existence of ``precursor film,'' which developed ahead of the imbibing front, and the dynamics of it is described well by another scaling law for capillary rise in a corner. Then, to show capabilities of open capillaries, we demonstrated two experiments by fabricating micro mixing devices to achieve (1) simultaneous multi-color change of the Bromothymol blue (BTB) solution and (2) expression of the green florescent protein (GFP). This research was partly supported by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). M. T. is supported by the Japan Society for the Promotion of Science Research Fellowships for Young Scientists.

  18. Planetary In Situ Capillary Electrophoresis System (PISCES)

    NASA Astrophysics Data System (ADS)

    Willis, P. A.; Stockton, A. M.; Mora, M. F.; Cable, M. L.; Bramall, N. E.; Jensen, E. C.; Jiao, H.; Lynch, E.; Mathies, R. A.

    2012-10-01

    We propose to develop PISCES, a 3-kg, 2W, flight-capable microfluidic lab-on-a-chip capillary electrophoresis analyzer capable of ingesting solid, liquid, or gas samples and performing a suite of chemical analyses with parts per trillion sensitivity.

  19. A Capillary Viscometer with a Bellows

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hiroshi; Yoshida, Kiyoshi; Kurano, Yasumitsu

    1991-06-01

    A new capillary viscometer using a bellows as a pressure supplier and a flow meter was developed. After calibration of the viscometer using distilled water, the viscosity of a viscosity standard oil JS 2.5 at 20°C was obtained with the accuracy of a few %.

  20. Capillary zone electrophoresis for analysis of complex proteomes using an electrokinetically pumped sheath flow nanospray interface

    PubMed Central

    Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing; Champion, Mathew M.

    2014-01-01

    The vast majority of proteomic studies employ reversed-phase high-performance liquid chromatography coupled with tandem mass spectrometry for analysis of the tryptic digest of a cellular lysate. This technology is quite mature, and typically provides identification of hundreds to thousands of peptides, which is used to infer the identity of hundreds to thousands of proteins. These approaches usually require milligrams to micrograms of starting material. Capillary zone electrophoresis provides an interesting alternative separation method based on a different separation mechanism than HPLC. Capillary electrophoresis received some attention for protein analysis beginning 25 years ago. Those efforts stalled because of the limited performance of the electrospray interfaces and the limited speed and sensitivity of mass spectrometers of that era. This review considers a new electrospray interface design coupled with Orbitrap Velos and linear Q-trap mass spectrometers. Capillary zone electrophoresis coupled with this interface and these detectors provides single shot detection of >1,250 peptides from an E. coli digest in less than one hour, identification of nearly 5,000 peptides from analysis of seven fractions produced by solid-phase extraction of the E. coli digest in a six hour total analysis time, low attomole detection limits for peptides generated from standard proteins, and high zeptomole detection limits for selected ion monitoring of peptides. Incorporation of an integrated on-line immobilized trypsin microreactor allows digestion and analysis of picogram amounts of a complex eukaryotic proteome. PMID:24277677

  1. Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions.

    PubMed

    Nilsson, Christian; Harwigsson, Ian; Becker, Kristian; Kutter, Jörg P; Birnbaum, Staffan; Nilsson, Staffan

    2010-01-01

    Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas, 6.7 cm effective length). In the absence of nanoparticles, i.e. in CE mode, the protein samples adsorbed completely to the capillary walls and could not be recovered. In contrast, nanoparticle-based capillary electroseparation resolved green fluorescent protein from several of its impurities within 1 min. Furthermore, a mixture of native green fluorescent protein and two of its single-amino-acid-substituted variants was separated within 2.5 min with efficiencies of 400 000 plates/m. The nanoparticles prevent adsorption by introducing a large interacting surface and by obstructing the attachment of the protein to the capillary wall. A one-step procedure based on self-assembly of lipids was used to prepare the nanoparticles, which benefit from their biocompatibility and suspension stability at high concentrations. An aqueous tricine buffer at pH 7.5 containing lipid-based nanoparticles (2% w/w) was used as electrolyte, enabling separation at protein friendly conditions. The developed capillary-based method facilitates future electrochromatography of proteins on polymer-based microchips under physiological conditions and enables the initial optimization of separation conditions in parallel to the chip development. PMID:20119954

  2. Stability measurements of antisense oligonucleotides by capillary gel electrophoresis.

    PubMed

    Bruin, G J; Börnsen, K O; Hüsken, D; Gassmann, E; Widmer, H M; Paulus, A

    1995-08-11

    The approach of using antisense oligonucleotides as potential drugs is based on hybridization of a short chemically-modified oligonucleotide with complementary cellular DNA or RNA sequences. A critical question is the stability of chemically modified antisense oligonucleotides in cellular environments. In a model system, resistance against various nucleases was evaluated by capillary gel electrophoresis (CGE). For some of the samples, matrix assisted laser desorption and ionization mass spectrometry (MALDI-MS) was used as an additional analytical tool to perform stability measurements. Using CGE, the enzymatic degradation of single nucleotides from the oligomer can be followed after different incubation times. 10% T polyacrylamide gels give baseline resolution for oligonucleotides ranging between 5 and 30 bases in length. The kinetic influence of a specific nuclease concentration and the antisense oligonucleotide structure on the cleavage reaction are discussed. Also, a simple desalting method to improve the injection efficiency and sensitivity of the method are described. Examples of measurements of chemically modified antisense 19-mers are presented. PMID:7581844

  3. Continuous full filling capillary electrochromatography-electrospraying chromatographic nanoparticles.

    PubMed

    Malmström, David; Axén, Jakob; Bergquist, Jonas; Viberg, Peter; Spégel, Peter

    2011-01-01

    The influence of instrumental parameters affecting the ionization in continuous full filling capillary electrochromatography/electrospray ionization mass spectrometry (CFF-CEC/ESI-MS) was investigated. The investigated parameters were the BGE and sheath liquid ion strength and organic modifier content, the nebulizer gas pressure, and the concentration of nanoparticles in the BGE. It was found that the nebulizer pressure had the largest influence on the separation efficiency and apparent retention. It was shown that even the lowest pressure investigated was sufficient to guide the nanoparticle flow away from the mass spectrometer inlet. A nebulizer pressure of 5 psi was found to be optimal; increasing the pressure significantly decreased the separation efficiency due to the generation of a hydrodynamic flow. Generally, the ion strength of both the BGE and the sheath liquid were found to have very moderate effects on the separation of a homologous series of dialkyl phthalates, whereas the ionization efficiency was found to be unaffected by the nanoparticles and the separation efficiency was found to increase with increasing concentrations up to 3.8 mg/mL, whereafter it was observed to drop. The optimized method was linear over a wide concentration range and presented LOD and LOQ more than threefold lower than those previously reported using CFF-CEC/ESI-MS. PMID:21254124

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

    PubMed

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

    2014-04-01

    A simple and rapid capillary electrophoresis method was developed for the separation and determination of ephedrine (E) and pseudoephedrine (PE) in a buffer solution containing 80 mM of NaH2PO4 (pH 3.0), 15 mM of β-cyclodextrin and 0.3% of hydroxypropyl methylcellulose. The field-amplified sample injection (FASI) technique was applied to the online concentration of the alkaloids. With FASI in the presence of a low conductivity solvent plug (water), an approximately 1,000-fold improvement in sensitivity was achieved without any loss of separation efficiency when compared to conventional sample injection. Under these optimized conditions, a baseline separation of the two analytes was achieved within 16 min and the detection limits for E and PE were 0.7 and 0.6 µg/L, respectively. Without expensive instruments or labeling of the compounds, the limits of detection for E and PE obtained by the proposed method are comparable with (or even lower than) those obtained by capillary electrophoresis laser-induced fluorescence, liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. The method was validated in terms of precision, linearity and accuracy, and successfully applied for the determination of the two alkaloids in Ephedra herbs. PMID:23619557

  5. Method of making tapered capillary tips with constant inner diameters

    DOEpatents

    Kelly, Ryan T.; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2009-02-17

    Methods of forming electrospray ionization emitter tips are disclosed herein. In one embodiment, an end portion of a capillary tube can be immersed into an etchant, wherein the etchant forms a concave meniscus on the outer surface of the capillary. Variable etching rates in the meniscus can cause an external taper to form. While etching the outer surface of the capillary wall, a fluid can be flowed through the interior of the capillary tube. Etching continues until the immersed portion of the capillary tube is completely etched away.

  6. Early capillary flux homogenization in response to neural activation.

    PubMed

    Lee, Jonghwan; Wu, Weicheng; Boas, David A

    2016-02-01

    This Brief Communication reports early homogenization of capillary network flow during somatosensory activation in the rat cerebral cortex. We used optical coherence tomography and statistical intensity variation analysis for tracing changes in the red blood cell flux over hundreds of capillaries nearly at the same time with 1-s resolution. We observed that while the mean capillary flux exhibited a typical increase during activation, the standard deviation of the capillary flux exhibited an early decrease that happened before the mean flux increase. This network-level data is consistent with the theoretical hypothesis that capillary flow homogenizes during activation to improve oxygen delivery. PMID:26661145

  7. Capillary Penetration into Inclined Circular Glass Tubes.

    PubMed

    Trabi, Christophe L; Ouali, F Fouzia; McHale, Glen; Javed, Haadi; Morris, Robert H; Newton, Michael I

    2016-02-01

    The spontaneous penetration of a wetting liquid into a vertical tube against the force of gravity and the imbibition of the same liquid into a horizontal tube (or channel) are both driven by capillary forces and described by the same fundamental equations. However, there have been few experimental studies of the transition from one orientation to the other. We report systematic measurements of capillary penetration of polydimethylsiloxane oils of viscosities 9.6, 19.2, and 48.0 mPa·s into glass capillary tubes. We first report the effect of tube radii R between 140 and 675 μm on the dynamics of spontaneous imbibition. We show that the data can be fitted using the exact numerical solution to the governing equations and that these are similar to fits using the analytical viscogravitational approximation. However, larger diameter tubes show a rate of penetration slower than expected using an equilibrium contact angle and the known value of liquid viscosity. To account for the slowness, an increase in viscosity by a factor (η/ρ)(scaling) is needed. We show full agreement with theory requires the ratio R/κ(-1) ∼ 0.1 or less, where κ(-1) is the capillary length. In addition, we propose an experimental method that enables the determination of the dynamic contact angle during imbibition, which gives values that agree with the literature values. We then report measurements of dynamic penetration into the tubes of R = 190 and 650 μm for a range of inclination angles to the horizontal, φ, from 5 to 90°. We show that capillary penetration can still be fitted using the viscogravitational solution, rather than the Bosanquet solution which describes imbibition without gravity, even for inclination angles as low as 10°. Moreover, at these low angles, the effect of the tube radius is found to diminish and this appears to relate to an effective capillary length, κ(-1)(φ) = (γ(LV)/ρg sin φ)(1/2). PMID:26738739

  8. Sterility Testing by Capillary Electrophoresis: A Comparison of On-line Preconcentration Approaches in Capillaries with Greater Internal Diameters

    PubMed Central

    Petr, Jan; Jiang, Chunxia; Sevcik, Juraj; Tesarova, Eva; Armstrong, Daniel W.

    2015-01-01

    Detection of microbial contamination is of critical importance in the medical and the food industry. Rapid tests for the absence or presence of viable microorganisms are in urgent demand. Capillary electrophoresis is a modern analytical technique that can be adapted for rapid screening of microbial contamination. However, the small dimensions of capillaries allow introduction of only a small fraction of the sample, which can be problematic when examining large samples. In this article, we examine the possibilities of introducing larger sample volumes using capillaries with greater internal diameters (i.d.) together with different stacking techniques. The use of 0.32 mm i.d. capillary and the injection of 60 % of the capillary volume led to approximately 120-fold improvement of the injected sample volume over the classical injection 5% of a 0.10 mm i.d. capillary. The setup we described opens new possibilities in sterility testing using capillary electrophoresis. PMID:19847804

  9. a Comprehensive Model for Capillary Pressure Difference across a Drop/bubble Flowing Through a Constricted Capillary

    NASA Astrophysics Data System (ADS)

    Liang, Mingchao; Wei, Junhong; Han, Hongmei; Fu, Chengguo; Liu, Jianjun

    2015-09-01

    The capillary pressure is one of the crucial parameters in many science and engineering applications such as composite materials, interface science, chemical engineering, oil exploration, etc. The drop/bubble formation and its mechanisms that affect the permeability of porous media have steadily attracted much attention in the past. When a drop/bubble moves from a larger capillary to a smaller one, it is often obstructed by an additional pressure difference caused by the capillary force. In this paper, a comprehensive model is derived for the capillary pressure difference when a drop/bubble flows through a constricted capillary, i.e. a geometrically constricted passage with an abrupt change in radius. The proposed model is expressed as a function of the smaller capillary radius, pore-throat ratio, contact angle, surface tension and length of the drop/bubble in the smaller capillary. The model predictions are compared with the available experimental data, and good agreement is found between them.

  10. Capillary flow through heat-pipe wicks

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1975-01-01

    Theoretical expressions are obtained for the capillary-pressure limit and permeability of a fibrous wick in terms of the porosity and fiber diameter. Hysteresis in capillary pressure is included through the introduction of an empirical hysteresis constant. A partial-saturation model based on the statistical distribution of local porosity requires an additional empirical constant, the standard deviation. The theory is compared to results of a beta-ray absorption experiment that measured the liquid content of a partially saturated wick and to results of permeability measurements on partially and fully saturated wicks. A simple wick-weighing experiment is described that yields values for the empirical hysteresis constant and the standard deviation. Theoretical results are used to design an optimum wick.

  11. Transversally periodic solitary gravity-capillary waves.

    PubMed

    Milewski, Paul A; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922

  12. High-performance capillary electrophoresis of histones

    SciTech Connect

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

    1991-01-01

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

  13. Capillary Study - Skylab Student Experiment ED-72

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This chart describes the Skylab student experiment ED-72, Capillary Study, proposed by Roger G. Johnson of St. Paul, Mirnesota. Johnson theorized that capillary rise might continue to infinity in Skylab's zero-gravity environment. The behavior of fluids, particularly their flow properties in a low-gravity environment, had been important from the time that Robert H. Goddard launched his liquid-fueled rockets in the 1920's to the more sophisticated space systems of the day. It was necessary to design fluid-flow systems that would not only overcome the lack of gravity but also overcome, or take advantage of, the effect of surface tension. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  14. Wetting kinetics in surface capillary grooves

    SciTech Connect

    Rye, R.R.; Yost, F.G.; Mann, J.A. Jr.

    1996-10-02

    For V-shaped surface grooves in copper, we have obtained the capillary driven flow kinetics for two liquids: unreactive 1-heptanol and eutectic Sn/Pb solder, which is known to react with copper. We show experimentally that the flow of both liquids in these grooves follows the classical Washburn kinetics, i.e., a Poiseuille flow process, modified to include a dynamic contact angle. Because no subsidiary processes are necessary to fit our data, we propose that in this geometry capillary driven solder flow is too rapid for reaction to provide an appreciable effect. Thus, to observe the effects of Sn/Cu reaction kinetics, the flow rate must be decreased, which the present experiments allow through redesign of the groove geometry and size. 16 refs., 4 figs.

  15. Capillary Hemangioma of the Fallopian Tube.

    PubMed

    Katiyar, Richa; Patne, Shashikant C U; Bharti, Shreekant; Jain, Madhu

    2016-04-01

    Neoplastic lesions of the fallopian tube are rarely seen by surgical pathologists. Haemangioma of the fallopian tube is an extremely rare benign neoplasm. A 30-year-old lady with polymenorrhea and dysmenorrhea underwent hysterectomy and bilateral salpingo-oophorectomy. Her left fallopian tube showed a 2mm sized solid nodule in the wall. Histopathological examination revealed a well-defined vascular lesion in the left fallopian tube, consistent with capillary haemangioma. The vascular endothelium was highlighted by CD34 immunostaining. Our literature review has identified 10 cases of cavernous haemangioma of the fallopian tube. To the best of our knowledge, we report the first ever case of capillary haemangioma of the fallopian tube. This is also the smallest detected haemangioma in the fallopian tube. PMID:27190899

  16. Capillary Hemangioma of the Fallopian Tube

    PubMed Central

    Katiyar, Richa; Bharti, Shreekant; Jain, Madhu

    2016-01-01

    Neoplastic lesions of the fallopian tube are rarely seen by surgical pathologists. Haemangioma of the fallopian tube is an extremely rare benign neoplasm. A 30-year-old lady with polymenorrhea and dysmenorrhea underwent hysterectomy and bilateral salpingo-oophorectomy. Her left fallopian tube showed a 2mm sized solid nodule in the wall. Histopathological examination revealed a well-defined vascular lesion in the left fallopian tube, consistent with capillary haemangioma. The vascular endothelium was highlighted by CD34 immunostaining. Our literature review has identified 10 cases of cavernous haemangioma of the fallopian tube. To the best of our knowledge, we report the first ever case of capillary haemangioma of the fallopian tube. This is also the smallest detected haemangioma in the fallopian tube. PMID:27190899

  17. Capillary solitons on a levitated medium.

    PubMed

    Perrard, S; Deike, L; Duchêne, C; Pham, C-T

    2015-07-01

    A water cylinder deposited on a heated channel levitates on its own generated vapor film owing to the Leidenfrost effect. This experimental setup permits the study of the one-dimensional propagation of surface waves in a free-to-move liquid system. We report the observation of gravity-capillary waves under a dramatic reduction of gravity (up to a factor 30), leading to capillary waves at the centimeter scale. The generated nonlinear structures propagate without deformation and undergo mutual collisions and reflections at the boundaries of the domain. They are identified as Korteweg-de Vries solitons with negative amplitude and subsonic velocity. The typical width and amplitude-dependent velocities are in excellent agreement with theoretical predictions based on a generalized Korteweg-de Vries equation adapted to any substrate geometry. When multiple solitons are present, they interact and form a soliton turbulencelike spectrum. PMID:26274114

  18. [Functional morphology of endonasal blood capillaries].

    PubMed

    Grevers, G

    1989-01-01

    Harvey (1628) was the first to describe the blood circulatory system. 50 years later, the capillary system was discovered by Marcello Malpighi as a link between arteries and veins. Since then, the microvascular network has been examined abundantly by means of various morphological and physiological techniques. During the last decades the development of the technical equipment enabled us to receive detailed informations on the structural and ultrastructural aspects of the vasculature and--particularly--the capillary endothelium. New electron microscopic investigations on the behaviour of this special cell system. In the present study we combined our own morphological results on the endonasal microcirculatory system--using different morphological techniques--to interpret these anatomical finding under functional aspects. PMID:2644502

  19. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    PubMed Central

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

    2016-01-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns. PMID:27245782

  20. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns.

  1. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide.

    PubMed

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

    2016-01-01

    The integration of microfluidic devices-which efficiently handle small liquid volumes-with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns. PMID:27245782

  2. Capillary-Effect Root-Environment System

    NASA Technical Reports Server (NTRS)

    Wright, Bruce D.

    1991-01-01

    Capillary-effect root-environment system (CERES) is experimental apparatus for growing plants in nutrient solutions. Solution circulated at slight tension in cavity filled with plastic screen and covered by porous plastic membrane. By adsorptive attraction, root draws solution through membrane. Conceived for use in microgravity of space, also finds terrestrial application in germinating seedlings, because it protects them from extremes of temperature, moisture, and soil pH and from overexposure to fertilizers and herbicides.

  3. The Microcephaly-Capillary Malformation Syndrome

    PubMed Central

    Mirzaa, Ghayda M.; Paciorkowski, Alex R.; Smyser, Christopher D.; Willing, Marcia C.; Lind, Anne C.; Dobyns, William B.

    2012-01-01

    We report on three children from two families with a new pattern recognition malformation syndrome consisting of severe congenital microcephaly (MIC), intractable epilepsy including infantile spasms, and generalized capillary malformations that was first reported recently in this journal [Carter et al. (2011); Am J Med Genet A 155: 301–306]. Two of our reported patients are an affected brother and sister, suggesting this is an autosomal recessive severe congenital MIC syndrome. PMID:21815250

  4. Novel cationic polyelectrolyte coatings for capillary electrophoresis.

    PubMed

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

    2016-01-01

    The use of bare fused silica capillary in CE can sometimes be inconvenient due to undesirable effects including adsorption of sample or instability of the EOF. This can often be avoided by coating the inner surface of the capillary. In this work, we present and characterize two novel polyelectrolyte coatings (PECs) poly(2-(methacryloyloxy)ethyl trimethylammonium iodide) (PMOTAI) and poly(3-methyl-1-(4-vinylbenzyl)-imidazolium chloride) (PIL-1) for CE. The coated capillaries were studied using a series of aqueous buffers of varying pH, ionic strength, and composition. Our results show that the investigated polyelectrolytes are usable as semi-permanent (physically adsorbed) coatings with at least five runs stability before a short coating regeneration is necessary. Both PECs showed a considerably decreased stability at pH 11.0. The EOF was higher using Good's buffers than with sodium phosphate buffer at the same pH and ionic strength. The thickness of the PEC layers studied by quartz crystal microbalance was 0.83 and 0.52 nm for PMOTAI and PIL-1, respectively. The hydrophobicity of the PEC layers was determined by analysis of a homologous series of alkyl benzoates and expressed as the distribution constants. Our result demonstrates that both PECs had comparable hydrophobicity, which enabled separation of compounds with log Po/w > 2. The ability to separate cationic drugs was shown with β-blockers, compounds often misused in doping. Both coatings were also able to separate hydrolysis products of the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene acetate at highly acidic conditions, where bare fused silica capillaries failed to accomplish the separation. PMID:26464098

  5. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D'Silva, Arthur

    1996-08-06

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

  6. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D`Silva, A.

    1996-08-06

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

  7. In situ synthesis of homochiral metal-organic framework in capillary column for capillary electrochromatography enantioseparation.

    PubMed

    Pan, Congjie; Wang, Weifeng; Zhang, Huige; Xu, Laifang; Chen, Xingguo

    2015-04-01

    Homochiral metal-organic frameworks (MOFs) are promising as porous stationary phase for open-tubular capillary electrochromatography (OT-CEC) enantioseparation owing to their fine-tuned pore sizes and large surface areas. In this work, the homochiral MOF AlaZnCl was successfully coated on the inner wall of fused silica capillary by an in situ, layer-by-layer self-assembly approach at room temperature. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD), streaming potential (SP) and Fourier-transform infrared spectroscopy (FT-IR) indicated that the homochiral MOF AlaZnCl was successfully coated on the capillary inner wall. To evaluate the performance of the homochiral MOF AlaZnCl coated capillary column, the enantioseparation was carried out by using six amine drugs and monoamine neurotransmitters as model analytes and excellent enantioseparation efficiency was achieved. Run-to-run, day-to-day, and column-to-column relative standard deviations (RSDs) were all less than 5%. Moreover, the separation efficiency of the homochiral MOF AlaZnCl coated capillary column did not decrease obviously over 100 runs. PMID:25725957

  8. Covalent bonding of homochiral metal-organic framework in capillaries for stereoisomer separation by capillary electrochromatography.

    PubMed

    Ma, Jichao; Ye, Nengsheng; Li, Jian

    2016-02-01

    In this work, a [Cu(mal)(bpy)]⋅H2O (mal, L-(-)-malic acid; bpy, 4,4'-bipyridyl) homochiral metal-organic frameworks (MOFs) was synthesized and used for modifying the inner walls of capillary columns by utilizing amido bonds to form covalent links between the MOFs particles and capillary inner wall. The synthesized [Cu(mal)(bpy)]⋅H2 O and MOFs-modified capillary column were characterized by X-ray diffraction, thermogravimetric analysis, particle size distribution analysis, nitrogen absorption characterization, FTIR spectroscopy, SEM, and energy-dispersive X-ray spectroscopy (EDX). The MOFs-modified capillary column was used for the stereoisomer separation of some drugs. The LODs and LOQs of six analytes were 0.1 and 0.25 μg/mL, respectively. The linear range was 0.25-250 μg/mL for ephedrine, 0.25-250 μg/mL for pseudoephedrine, 0.25-180 μg/mL for D-penicillamine, 0.25-120 μg/mL for L-penicillamine, 0.25-180 μg/mL for D-phenylalanine, and 0.25-160 μg/mL for L-phenylalanine, all with R(2) > 0.999. Finally, the MOFs-modified capillary column was applied for the analysis of active ingredients in a real sample of the traditional Chinese medicine ephedra. PMID:26542186

  9. Highly conductive, printable pastes from capillary suspensions

    NASA Astrophysics Data System (ADS)

    Schneider, Monica; Koos, Erin; Willenbacher, Norbert

    2016-08-01

    We have used the capillary suspension phenomenon to design conductive pastes for printed electronic applications, such as front side metallization of solar cells, without non-volatile, organic additives that often deteriorate electrical properties. Adding a small amount of a second, immiscible fluid to a suspension creates a network of liquid bridges between the particles. This capillary force-controlled microstructure allows for tuning the flow behavior in a wide range. Yield stress and low-shear viscosity can be adjusted such that long-term stability is provided by inhibiting sedimentation, and, even more importantly, narrow line widths and high aspect ratios are accessible. These ternary mixtures, called capillary suspensions, exhibit a strong degree of shear thinning that allows for conventional coating or printing equipment to be used. Finally, the secondary fluid, beneficial for stability and processing of the wet paste, completely evaporates during drying and sintering. Thus, we obtained high purity silver and nickel layers with a conductivity two times greater than could be obtained with state-of-the-art, commercial materials. This revolutionary concept can be easily applied to other systems using inorganic or even organic conductive particles and represents a fundamental paradigm change to the formulation of pastes for printed electronics.

  10. Highly conductive, printable pastes from capillary suspensions.

    PubMed

    Schneider, Monica; Koos, Erin; Willenbacher, Norbert

    2016-01-01

    We have used the capillary suspension phenomenon to design conductive pastes for printed electronic applications, such as front side metallization of solar cells, without non-volatile, organic additives that often deteriorate electrical properties. Adding a small amount of a second, immiscible fluid to a suspension creates a network of liquid bridges between the particles. This capillary force-controlled microstructure allows for tuning the flow behavior in a wide range. Yield stress and low-shear viscosity can be adjusted such that long-term stability is provided by inhibiting sedimentation, and, even more importantly, narrow line widths and high aspect ratios are accessible. These ternary mixtures, called capillary suspensions, exhibit a strong degree of shear thinning that allows for conventional coating or printing equipment to be used. Finally, the secondary fluid, beneficial for stability and processing of the wet paste, completely evaporates during drying and sintering. Thus, we obtained high purity silver and nickel layers with a conductivity two times greater than could be obtained with state-of-the-art, commercial materials. This revolutionary concept can be easily applied to other systems using inorganic or even organic conductive particles and represents a fundamental paradigm change to the formulation of pastes for printed electronics. PMID:27506726

  11. Microfab-less Microfluidic Capillary Electrophoresis Devices

    PubMed Central

    Segato, Thiago P.; Bhakta, Samir A.; Gordon, Matthew; Carrilho, Emanuel; Willis, Peter A.; Jiao, Hong; Garcia, Carlos D.

    2013-01-01

    Compared to conventional bench-top instruments, microfluidic devices possess advantageous characteristics including great portability potential, reduced analysis time (minutes), and relatively inexpensive production, putting them on the forefront of modern analytical chemistry. Fabrication of these devices, however, often involves polymeric materials with less-than-ideal surface properties, specific instrumentation, and cumbersome fabrication procedures. In order to overcome such drawbacks, a new hybrid platform is proposed. The platform is centered on the use of 5 interconnecting microfluidic components that serve as the injector or reservoirs. These plastic units are interconnected using standard capillary tubing, enabling in-channel detection by a wide variety of standard techniques, including capacitively-coupled contactless conductivity detection (C4D). Due to the minimum impact on the separation efficiency, the plastic microfluidic components used for the experiments discussed herein were fabricated using an inexpensive engraving tool and standard Plexiglas. The presented approach (named 52-platform) offers a previously unseen versatility: enabling the assembly of the platform within minutes using capillary tubing that differs in length, diameter, or material. The advantages of the proposed design are demonstrated by performing the analysis of inorganic cations by capillary electrophoresis on soil samples from the Atacama Desert. PMID:23585815

  12. Highly multiplexed DNA sequencing by capillary electrophoresis

    SciTech Connect

    Yeung, E.S.; Ueno, K.; Chang, H.T.

    1994-12-31

    It is obvious that irrespective of whichever basic technology is eventually selected to sequence the entire human genome there are substantial gains to be made if a high degree of multiplexing of parallel runs can be implemented. Such multiplexing should not involve expensive instrumentation and should not require additional personnel, or else the main objective of cost reduction will not be satisfied even though the total time for sequencing is reduced. In the last two years, several research groups have shown that capillary electrophoresis (CE) is an attractive alternative for DNA sequencing. Part of the improvement in sequencing speed in CE is counteracted by the inherent ability of slab gels for accommodating multiple lanes in a single run. Recently, the authors have developed several excitation schemes for highly multiplexed capillary electrophoresis. Detection at the pM level was demonstrated. The authors report here the use of a novel excitation geometry to simultaneously monitor 100 capillary tubes during electrophoresis. This represents a truly parallel multiplexing scheme for high-speed DNA sequencing.

  13. Determination of surfactants by capillary electrophoresis.

    PubMed

    Heinig, K; Vogt, C

    1999-10-01

    Capillary electrophoresis has been increasingly used during the past few years for the separation and determination of surfactants. These substances are applied in many household and industrial products such as laundry detergents, cosmetics and pharmaceuticals, often as homologous and isomeric mixtures. Product development and control as well as toxicological and environmental analyses require selective and sensitive analytical methods. This review presents capillary electrophoretic techniques to determine important representatives of cationic, anionic, and neutral surfactants. The application of different buffer additives such as organic solvents, cyclodextrins or micelles to enhance the resolution of complex mixtures is discussed. Besides direct and indirect UV and fluorescence detection, examples for conductivity and mass spectrometric detection are also given. Derivatization procedures to improve the detectability and implement charge in neutral analytes are described. The successful use of capillary electrophoresis for surfactant determinations has proven that it can serve as a routine technique in many real-world applications. Robust, validated methods for the quantitation of single compounds, such as alkylbenzene sulfonates, sodium dodecyl sulfate and benzalkonium salts, are now available. Characteristic peak patterns (fingerprint analysis) can be used for the identification of surfactants in multicomponent formulations (e.g. ethoxylates and phosphonates). PMID:10596832

  14. Drinking in Space: The Capillary Beverage Experiment

    NASA Astrophysics Data System (ADS)

    Wollman, Andrew; Weislogel, Mark; Jenson, Ryan; Graf, John; Pettit, Donald; Kelly, Scott; Lindgren, Kjell; Yui, Kimiya

    2015-11-01

    A selection from as many as 50 different drinks including coffees, teas, and fruit smoothies are consumed daily by astronauts aboard the International Space Station. For practical reasons, the drinks are generally sipped through straws inserted in sealed bags. We present the performance of a special cup designed to allow the drinking operation in much the same manner as on earth, only with the role of gravity replaced by the combined effects of surface tension, wetting, and special container geometry. One can finally `smell the coffee.' Six so-called Space Cups are currently in orbit as part of the Capillary Beverage Experiment which aims to demonstrate specific passive control of poorly wetting aqueous capillary systems through a fun mealtime activity. The mathematical fluid mechanical design process with full numerical simulations is presented alongside experimental results acquired using a drop tower and low-g aircraft before complete characterization aboard the Space Station. Astronaut commentary is both humorous and informative, but the insightful experimental results of the potable space experiment testify to the prospects of new no-moving-parts capillary solutions for certain water-based life support operations aboard spacecraft.

  15. The order of condensation in capillary grooves.

    PubMed

    Rascón, Carlos; Parry, Andrew O; Nürnberg, Robert; Pozzato, Alessandro; Tormen, Massimo; Bruschi, Lorenzo; Mistura, Giampaolo

    2013-05-15

    We consider capillary condensation in a deep groove of width L. The transition occurs at a pressure p(co)(L) described, for large widths, by the Kelvin equation p(sat) - p(co)(L) = 2σ cosθ/L, where θ is the contact angle at the side walls and σ is the surface tension. The order of the transition is determined by the contact angle of the capped end θcap; it is continuous if the liquid completely wets the cap, and first-order otherwise. When the transition is first-order, corner menisci at the bottom of the capillary lead to a pronounced metastability, determined by a complementary Kelvin equation Δp(L) = 2σ sinθcap/L. On approaching the wetting temperature of the capillary cap, the corner menisci merge and a single meniscus unbinds from the bottom of the groove. Finite-size scaling shifts, crossover behaviour and critical singularities are determined at mean-field level and beyond. Numerical and experimental results showing the continuous nature of condensation for θcap = 0 and the influence of corner menisci on adsorption isotherms are presented. PMID:23611878

  16. Capillary-scale polarimetry for flowing streams.

    PubMed

    Swinney, K; Nodorft, J; Bornhop, D J

    2001-05-01

    A micro-polarimeter with a 40 nL probe volume was configured so that it is compatible with capillary-scale flowing stream analysis. The optical configuration consists of two polarizing optics, a capillary, a laser source and a photodetector which is very simple to configure with low cost components. This unique polarimeter is based upon the interaction of a linearly polarized laser beam and a capillary tube, in this case one with an inner diameter of 250 microns. Side illumination of the tube results in a 360 degrees fan of scattered light, which contains a set of interference fringes that change in response to optically active solutes. Solutes that exhibit optical activity are quantifiable and are detected by analyzing the polarization state of the backscattered light. The ability of the instrument to make extremely sensitive optical activity measurements in flowing streams is shown by the determination of (R)-mandelic acid, with a detection limit of 66 x 10(-6) M (507 x 10(-12) g), and the non-optically active control, glycerol. Additionally, the detector was configured to minimize refractive index perturbations. PMID:11394312

  17. Highly conductive, printable pastes from capillary suspensions

    PubMed Central

    Schneider, Monica; Koos, Erin; Willenbacher, Norbert

    2016-01-01

    We have used the capillary suspension phenomenon to design conductive pastes for printed electronic applications, such as front side metallization of solar cells, without non-volatile, organic additives that often deteriorate electrical properties. Adding a small amount of a second, immiscible fluid to a suspension creates a network of liquid bridges between the particles. This capillary force-controlled microstructure allows for tuning the flow behavior in a wide range. Yield stress and low-shear viscosity can be adjusted such that long-term stability is provided by inhibiting sedimentation, and, even more importantly, narrow line widths and high aspect ratios are accessible. These ternary mixtures, called capillary suspensions, exhibit a strong degree of shear thinning that allows for conventional coating or printing equipment to be used. Finally, the secondary fluid, beneficial for stability and processing of the wet paste, completely evaporates during drying and sintering. Thus, we obtained high purity silver and nickel layers with a conductivity two times greater than could be obtained with state-of-the-art, commercial materials. This revolutionary concept can be easily applied to other systems using inorganic or even organic conductive particles and represents a fundamental paradigm change to the formulation of pastes for printed electronics. PMID:27506726

  18. One-step multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by preparative capillary gas with characterization by spectroscopic and spectrometric techniques and evaluation of biological activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the present work multiple component isolation from the oil of Crinitaria tatarica (Less.) Sojak. by Preparative Capillary Gas Chromatography (PCGC) with characterization by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have been carried out. Gas chromatography (GC-FID) ...

  19. SPECIATION OF SELENIUM AND ARSENIC COMPOUNDS BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW AND ON-LINE REDUCTION OF SELENIUM(VI) TO SELENIUM(IV) WITH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC DETECTION

    EPA Science Inventory

    Capillary electrophoresis (CE) with hydride generation inductively coupled plasma mass spectrometry was used to determine four arsenicals and two selenium species. Selenate (SeVI) was reduced on-line to selenite (SeIV') by mixing the CE effluent with concentrated HCl. A microporo...

  20. Quantitative analysis of nailfold capillary morphology in patients with fibromyalgia

    PubMed Central

    Choi, Dug-Hyun

    2015-01-01

    Background/Aims Nailfold capillaroscopy (NFC) has been used to examine morphological and functional microcirculation changes in connective tissue diseases. It has been demonstrated that NFC patterns reflect abnormal microvascular dynamics, which may play a role in fibromyalgia (FM) syndrome. The aim of this study was to determine NFC patterns in FM, and their association with clinical features of FM. Methods A total of 67 patients with FM, and 30 age- and sex-matched healthy controls, were included. Nailfold capillary patterns were quantitatively analyzed using computerized NFC. The parameters of interest were as follows: number of capillaries within the central 3 mm, deletion score, apical limb width, capillary width, and capillary dimension. Capillary dimension was determined by calculating the number of capillaries using the Adobe Photoshop version 7.0. Results FM patients had a lower number of capillaries and higher deletion scores on NFC compared to healthy controls (17.3 ± 1.7 vs. 21.8 ± 2.9, p < 0.05; 2.2 ± 0.9 vs. 0.7 ± 0.6, p < 0.05, respectively). Both apical limb width (µm) and capillary width (µm) were significantly decreased in FM patients (1.1 ± 0.2 vs. 3.7 ± 0.6; 5.4 ± 0.5 vs. 7.5 ± 1.4, respectively), indicating that FM patients have abnormally decreased digital capillary diameter and density. Interestingly, there was no difference in capillary dimension between the two groups, suggesting that the length or tortuosity of capillaries in FM patients is increased to compensate for diminished microcirculation. Conclusions FM patients had altered capillary density and diameter in the digits. Diminished microcirculation on NFC may alter capillary density and increase tortuosity. PMID:26161020

  1. Measurement of Capillary Radius and Contact Angle within Porous Media.

    PubMed

    Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

    2015-12-01

    The pore radius (i.e., capillary radius) and contact angle determine the capillary pressure generated in a porous medium. The most common method to determine these two parameters is through measurement of the capillary pressure generated by a reference liquid (i.e., a liquid with near-zero contact angle) and a test liquid. The rate of rise technique, commonly used to determine the capillary pressure, results in significant uncertainties. In this study, we utilize a recently developed technique for independently measuring the capillary pressure and permeability to determine the equivalent minimum capillary radii and contact angle of water within micropillar wick structures. In this method, the experimentally measured dryout threshold of a wick structure at different wicking lengths is fit to Darcy's law to extract the maximum capillary pressure generated by the test liquid. The equivalent minimum capillary radii of different wick geometries are determined by measuring the maximum capillary pressures generated using n-hexane as the working fluid. It is found that the equivalent minimum capillary radius is dependent on the diameter of pillars and the spacing between pillars. The equivalent capillary radii of micropillar wicks determined using the new method are found to be up to 7 times greater than the current geometry-based first-order estimates. The contact angle subtended by water at the walls of the micropillars is determined by measuring the capillary pressure generated by water within the arrays and the measured capillary radii for the different geometries. This mean contact angle of water is determined to be 54.7°. PMID:26538412

  2. Trajectory of isoelectric focusing from gels to capillaries to immobilized gradients in capillaries

    PubMed Central

    Koshel, Brooke M.; Wirth, Mary J.

    2013-01-01

    This review presents the need for replacing gels in 2D separations for proteomics, where speed, high-throughput, and the ability to characterize trace level proteins or small samples are the current desires. The theme of the review is isoelectric focusing, which is a valuable tool because it pre-concentrates proteins in addition to separating with high peak capacity. The review traces the technological progress from gel IEF to cIEF to packed capillaries with immobilized gradients for cIEF. Multiple capillary techniques are progressing toward meeting the current desires, providing extremely high sensitivity with regard to concentration and to small samples, integrated automation, and high peak capacity from multiple dimensions of separation. Capillaries with immobilized pH gradients for cIEF are emerging, which will alleviate interference from ampholytes and improve reproducibility in separation times when this valuable technique can be used as one of the dimensions. PMID:22930445

  3. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  4. Nuclear Magnetic Resonance Spectrometry.

    ERIC Educational Resources Information Center

    Wasson, John R.; Salinas, Jorge E.

    1980-01-01

    Reviews current research in NMR spectrometry, in the areas of apparatus and techniques, spectral analysis, computer applications, analytical applications, and selected organic and inorganic systems. Various aspects of NMR spectrometry are presented in tabular form, with 133 references. Listed also are 124 references from the discussions in the…

  5. Separation of DNA restriction fragments using capillary electrophoresis

    SciTech Connect

    Chan, K.C.; Whang, Chenwen; Yeung, E.S. )

    1993-01-01

    Gel-filled and non-gel' capillary electrophoresis (CE) have been applied to the separation of various DNA restriction fragments. 30% HydroLink gel, polymerized inside a 75[mu]m i.d. fused-silica capillary, was used in the gel-filled CE. Primary results show that the HL capillary gel was simple to cast, and its stability was reasonably good under the running conditions. In the non-gel CE experiment, a buffer containing the sieving additive hydroxypropylmethyl cellulose was used to affect the size-dependent separation. The use of GC capillaries eliminates the inconvenience of separately coating the capillary walls for efficient non-gel separation. Finally, the authors demonstrate that it is feasible to detect native DNA fragments using indirect fluorometry in non-gel capillary electrophoresis.

  6. An axial approach to detection in capillary electrophoresis

    SciTech Connect

    Taylor, J.A.

    1993-05-01

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

  7. Reshaping of intense laser pulse with a capillary

    SciTech Connect

    Cao Lihua; Yu Wei; Yu, M. Y.; Wang Xin; Gu Yuqiu; He, X. T.

    2009-09-15

    The reshaping of intense laser pulse by vacuum capillary is studied by particle-in-cell simulation. It is shown that as an intense laser pulse propagates from free space into a capillary, its profile is reshaped due to laser-plasma interaction near the entrance of capillary. As a result, the free-space mode is self-consistently converted into a capillary mode. Only the relatively low-intensity periphery of the reshaped pulse interacts with the capillary-wall plasma, so that the high-intensity center of the pulse can propagate in the narrow vacuum channel over a distance much larger than the Rayleigh length. The mechanism is then applied to reshape a radially imperfect laser pulse having two wings around the center spot. Most of the output light energy is concentrated in the center spot, and the wings are almost completely removed. That is, the quality of the laser pulse can be greatly improved by a capillary.

  8. Colloid Mobilization and Transport during Capillary Fringe Fluctuations

    NASA Astrophysics Data System (ADS)

    Aramrak, Surachet; Flury, Markus

    2016-04-01

    Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead filled column. Confocal images showed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively-charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively-charged colloids did not attach to static air-bubbles, but hydrophobic negatively-charged and hydrophilic positively-charged colloids did.

  9. Ion mobility spectrometry for detection of skin volatiles

    PubMed Central

    Ruzsanyi, Veronika; Mochalski, Pawel; Schmid, Alex; Wiesenhofer, Helmut; Klieber, Martin; Hinterhuber, Hartmann; Amann, Anton

    2012-01-01

    Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin. PMID:23217311

  10. Plasma mass spectrometry as a detector for chemical speciation studies.

    PubMed

    Tomlinson, M J; Lin, L; Caruso, J A

    1995-03-01

    Inductively coupled plasma mass spectrometry (ICP-MS), when coupled with the unique separating power of various chromatographic techniques, allows the detection of various elements at ultra-trace levels. The investigation of various toxic elements of environmental concern coupling relatively recent techniques, such as supercritical fluid chromatography (SFC) and capillary zone electrophoresis (CZE), to ICP-MS, is discussed. Comparisons have been made with detection limits obtained by using the flame ionization detector. The conventional technique of liquid chromatography for the speciation of vanadium, chromium and nickel is also discussed. PMID:7741220

  11. Capillary optics for micro x-ray fluorescence analysis

    SciTech Connect

    Bjeoumikhov, A.; Langhoff, N.; Bjeoumikhova, S.; Wedell, R.

    2005-06-15

    Practically achieved parameters of capillary optics are presented. A micro x-ray fluorescence (XRF) arrangement was realized by using a microfocus x-ray tube and a capillary optic. Several examples for application of micro XRF are given. It was shown that polycapillary lenses free of the 'halo effect' well suited for micro XRF of heavy elements can be manufactured. Limits of opportunities for micro XRF applications and further development for micro XRF by using capillary optics are analyzed.

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

    DOEpatents

    Yeung, Edwards; Kuhr, Werner G.

    1991-04-09

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

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

    DOEpatents

    Yeung, Edward S.; Kuhr, Werner G.

    1996-02-20

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

  14. Capillary-Condenser-Pumped Heat-Transfer Loop

    NASA Technical Reports Server (NTRS)

    Silverstein, Calvin C.

    1989-01-01

    Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

  15. Multiple beam interference model for measuring parameters of a capillary.

    PubMed

    Xu, Qiwei; Tian, Wenjing; You, Zhihong; Xiao, Jinghua

    2015-08-01

    A multiple beam interference model based on the ray tracing method and interference theory is built to analyze the interference patterns of a capillary tube filled with a liquid. The relations between the angular widths of the interference fringes and the parameters of both the capillary and liquid are derived. Based on these relations, an approach is proposed to simultaneously determine four parameters of the capillary, i.e., the inner and outer radii of the capillary, the refractive indices of the liquid, and the wall material. PMID:26368114

  16. Fluorinated ethylenepropylene copolymer as a potential capillary material in CE.

    PubMed

    Evenhuis, Christopher J; Yang, Wen-Chu; Johns, Cameron; Macka, Miroslav; Haddad, Paul R

    2007-10-01

    In this work, a new generation UV-transparent polymer, fluorinated ethylenepropylene copolymer (FEP) exhibiting a low degree of crystallinity, extruded in dimensions similar to the most commonly used CE capillaries of approximately 80 mum id and about 360 mum od was investigated for its use as a CE capillary. FEP is transparent down to the low-UV region, and as fluorinated polymers in general are good electrical insulators and exhibit reasonable heat conductivity, it has considerable potential as a material for electrodriven analysis in capillary or microchip formats. The FEP capillary has been characterised with regard to some important aspects for its use as a CE capillary, including its profile of EOF versus pH, as well as procedures for manipulating EOF by coating the inner capillary wall with various semipermanent and dynamic layers. The FEP capillaries were tested and compared with fused-silica capillary for the separation of inorganic and small organic ions using conditions involving direct and indirect detection in the low-UV region. Finally, advantages of the use of the FEP capillary for simultaneous detection of a mixture containing nine inorganic cations and anions using indirect photometric detection with a movable light-emitting diode (LED) detector and a novel electrolyte are demonstrated. PMID:17847133

  17. Cell trapping in a blood capillary phantom using laser tweezers

    NASA Astrophysics Data System (ADS)

    Klykov, Sergei S.; Fedosov, Ivan V.; Tuchin, Valery V.

    2015-03-01

    As a phantom of native blood capillary the plastic capillary tube and as a model of red blood cells the yeast cells are considered. Plastic capillary has circular a cross-section with diameter ranging between 20 and 40 μ. For velocity estimation of polystyrene beads which had a role of tracers in water the particle image velocimetry method is realized using NI Labview Vision standard functions of image processing. It is shown that in spite of the presence of uncompensated spherical aberration emerging from refraction incident beam in curved plastic capillary walls yeast cells can be confined in stable 3D trap.

  18. A Prediction Model of the Capillary Pressure J-Function.

    PubMed

    Xu, W S; Luo, P Y; Sun, L; Lin, N

    2016-01-01

    The capillary pressure J-function is a dimensionless measure of the capillary pressure of a fluid in a porous medium. The function was derived based on a capillary bundle model. However, the dependence of the J-function on the saturation Sw is not well understood. A prediction model for it is presented based on capillary pressure model, and the J-function prediction model is a power function instead of an exponential or polynomial function. Relative permeability is calculated with the J-function prediction model, resulting in an easier calculation and results that are more representative. PMID:27603701

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

    PubMed Central

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

    2016-01-01

    Soluble sugars play an important role in freezing tolerance in both herbaceous and woody plants, functioning in both the reduction of freezing-induced dehydration and the cryoprotection of cellular constituents. The quantification of soluble sugars in plant tissues is, therefore, essential in understanding freezing tolerance. While a number of analytical techniques and methods have been used to quantify sugars, most of these are expensive and time-consuming due to complex sample preparation procedures which require the derivatization of the carbohydrates being analyzed. Analysis of soluble sugars using capillary zone electrophoresis (CZE) under alkaline conditions with direct UV detection has previously been used to quantify simple sugars in fruit juices. However, it was unclear whether CZE-based methods could be successfully used to quantify the broader range of sugars present in complex plant extracts. Here, we present the development of an optimized CZE method capable of separating and quantifying mono-, di-, and tri-saccharides isolated from plant tissues. This optimized CZE method employs a column electrolyte buffer containing 130 mM NaOH, pH 13.0, creating a current of 185 μA when a separation voltage of 10 kV is employed. The optimized CZE method provides limits-of-detection (an average of 1.5 ng/μL) for individual carbohydrates comparable or superior to those obtained using gas chromatography–mass spectrometry, and allows resolution of non-structural sugars and cell wall components (structural sugars). The optimized CZE method was successfully used to quantify sugars from grape leaves and buds, and is a robust tool for the quantification of plant sugars found in vegetative and woody tissues. The increased analytical efficiency of this CZE method makes it ideal for use in high-throughput metabolomics studies designed to quantify plant sugars. PMID:27379118

  20. Effective viscosity of magnetic nanofluids through capillaries

    NASA Astrophysics Data System (ADS)

    Patel, Rajesh

    2012-02-01

    The simultaneous effect of magnetic field and temperature on the capillary viscosity of magnetic nanofluid is an important parameter for a new class of applications such as nanoduct flow, nanomotors, micro- and nanofluidic devices, for transformer cooling, magnetic targeted drug delivery, etc. The effective viscosity of a nanofluid is explained based on the rotation of the particles and the effect of torque on it due to an externally applied magnetic field. Two types of fluids are used here, temperature-sensitive and non-temperature-sensitive magnetic nanofluids. In both types of fluids, decrease in effective viscosity with temperature is observed, but in both cases the mechanism for the decrement is quite different. One is due to temperature dependence of the magnetic moment and the other is due to removal of the secondary surfactant. For temperature-sensitive magnetic nanofluids, a Curie temperature of ˜80 ∘C is extracted from this study. For non-temperature-sensitive magnetic nanofluids ˜65% of the secondary surfactant is removed for a change in temperature, ΔT = 40 ∘C. This is analogous with removal of a drug from magnetic particles for targeted drug delivery. Further, a linear dependence of effective viscosity with different capillary size and ξ (angle between magnetic field and flow direction, ξ∈[0,π/2]) is also observed. This linear dependence can also be a good approximation for the study of magnetic drug targeting, as in the human body the capillaries are of different sizes, and the externally applied magnetic field is not always parallel or perpendicular to the drug flow direction.

  1. Effective viscosity of magnetic nanofluids through capillaries.

    PubMed

    Patel, Rajesh

    2012-02-01

    The simultaneous effect of magnetic field and temperature on the capillary viscosity of magnetic nanofluid is an important parameter for a new class of applications such as nanoduct flow, nanomotors, micro- and nanofluidic devices, for transformer cooling, magnetic targeted drug delivery, etc. The effective viscosity of a nanofluid is explained based on the rotation of the particles and the effect of torque on it due to an externally applied magnetic field. Two types of fluids are used here, temperature-sensitive and non-temperature-sensitive magnetic nanofluids. In both types of fluids, decrease in effective viscosity with temperature is observed, but in both cases the mechanism for the decrement is quite different. One is due to temperature dependence of the magnetic moment and the other is due to removal of the secondary surfactant. For temperature-sensitive magnetic nanofluids, a Curie temperature of ~80 °C is extracted from this study. For non-temperature-sensitive magnetic nanofluids ~65% of the secondary surfactant is removed for a change in temperature, ΔT = 40 °C. This is analogous with removal of a drug from magnetic particles for targeted drug delivery. Further, a linear dependence of effective viscosity with different capillary size and ξ (angle between magnetic field and flow direction, ξε[0,π/2]) is also observed. This linear dependence can also be a good approximation for the study of magnetic drug targeting, as in the human body the capillaries are of different sizes, and the externally applied magnetic field is not always parallel or perpendicular to the drug flow direction. PMID:22463326

  2. Analysis of monoclonal antibody heterogeneity by post-capillary affinity detection for capillary electrophoresis

    SciTech Connect

    Kelly, J.A.; Lee, Cheng S.

    1997-12-31

    Production of monoclonal antibodies seldom results in a single uniform product. Although the use of hybridomas yields antibodies with a homogeneous amino acid sequence, differences exist in degree of glycosylation. Oligosaccharide variation is known to vary with culture conditions as well as proliferation state. Glycosylation is significant biologically, particularly agalactosyl glycoforms of IgG which can be pathogenic. This suggests a need for rapid analysis of antibody heterogeneity, including glycosylation, during production to optimize quality and yield. Post-capillary affinity detection for capillary electrophoresis is a novel bioanalytical tool which analyzes protein microheterogeneity without interference from complex sample matrices. Mouse monoclonal antibody samples from cell culture media are selectively analyzed by post-capillary affinity detection. Separation of IgG variants is accomplished by capillary zone electrophoresis (CZE) prior to on-line affinity detection with fragment B of Protein A lagged with fluorescein (BF). IgG isoforms are observed while serum proteins and cell culture media are discriminated against.

  3. Capillary zone electrophoresis and packed capillary column liquid chromatographic analysis of recombinant human interleukin-4.

    PubMed

    Bullock, J

    1993-02-24

    Capillary zone electrophoresis (CZE) and packed capillary column liquid chromatography (micro-LC) have been applied to the analysis of the recombinant human protein interleukin-4 (rhIL-4). Separations for both the parent protein and its enzymatic digest were developed for the purpose of characterizing protein purity and identity. CZE separations of the intact protein were investigated over the pH range of 4.5 to 8.0 using uncoated fused silica capillaries. Gradient reversed-phase micro-LC was performed using 0.32 mm packed capillary columns at flow-rates of 5-6 microliters/min. Emphasis was placed on the ability of these methods to separate close structural variants and degradation products of the protein. Peptide mapping of the tryptic digest of rhIL-4 using a combination of CZE and micro-LC provided complimentary high resolution methods for establishing protein identity. Reproducible separations were achieved using sub-picomol amounts of sample. The advantages and problems encountered with these two techniques for characterizing rhIL-4 were assessed. PMID:8450025

  4. Determination of glycyrrhizin in liqueurs by on-line coupled capillary isotachophoresis with capillary zone electrophoresis.

    PubMed

    Kvasnicka, Frantisek; Voldrich, Michal; Vyhnálek, Josef

    2007-10-26

    An on-line coupled capillary isotachophoresis-capillary zone electrophoresis method for the determination of glycyrrhizin in liqueurs is described. The optimised electrolyte system was 5 mM HCl+11 mM epsilon-aminocaproic acid+0.05% hydroxyethylcellulose+30% methanol (leading electrolyte), 5 mM caproic acid+30% methanol (terminating electrolyte) and 20 mM caproic acid+10 mM histidine+0.1% hydroxyethylcellulose+30% methanol (background electrolyte). Method characteristics, i.e., linearity (20-500 ng/ml), accuracy (recovery 99+/-4%), intra-assay repeatability (2%), intermediate repeatability (3.8%) and detection limit (8 ng/ml) were determined. Speed of analysis, low laboriousness, high sensitivity and low-running cost are the typical attributes of the capillary isotachophoresis-capillary zone electrophoresis method. Developed method was successfully applied to analysis of liqueurs with liquorice extract and some foods (sweets and food supplements) containing liquorice. Found levels of glycyrrhizin in liqueurs, sweets and food supplements varied between 1-16 mg/l, 850-1050 mg/kg and 1.6-1.8 g/kg, respectively. PMID:17875310

  5. Microfabricated capillary array electrophoresis device and method

    DOEpatents

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

    2004-06-15

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

  6. Microfabricated capillary array electrophoresis device and method

    DOEpatents

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

    2000-01-01

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

  7. Convective dominated flows in open capillary channels

    NASA Astrophysics Data System (ADS)

    Rosendahl, Uwe; Grah, Aleksander; Dreyer, Michael E.

    2010-05-01

    This paper is concerned with convective dominated liquid flows in open capillary channels. The channels consist of two parallel plates bounded by free liquid surfaces along the open sides. In the case of steady flow the capillary pressure of the free surface balances the differential pressure between the liquid and the surrounding constant pressure gas phase. A maximum flow rate is achieved when the adjusted volumetric flow rate exceeds a certain limit leading to a collapse of the free surfaces. The convective dominated flow regime is a special case of open capillary flow, since the viscous forces are negligibly small compared with the convective forces. Flows of this type are of peculiar interest since the free surfaces possess a quasisymmetry in the flow direction. This quasisymmetry enables the application of a new effective method for evaluation of the flow limit. The flow limit is caused by a choking effect. This effect is indicated by the speed index, S, which is defined by the ratio of the flow velocity and the longitudinal capillary wave speed. The speed index is defined analogously to Mach number and tends toward unity in the case of flow limitation, i.e., when the maximum flow rate is reached. Utilizing the quasisymmetry, a new approach for a very precise determination of the speed index is presented. This approach uses a new approximation for the curvature of the surfaces by means of the empirical surface profiles. On the basis of empirical and theoretical data, the paper discusses the typical features of the stable flow. The experiments were performed under microgravity aboard the sounding rockets TEXUS 41 and TEXUS 42. The experiment setup enables the approach to the flow limit through either increase in flow rate or channel length. The theoretical data have been gained from numerical solutions of a one-dimensional flow model. The empirical and theoretical results are in good agreement and both confirm the choking effect as cause of the flow limitation

  8. Metallized Capillaries as Probes for Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Pelletier, Michael

    2003-01-01

    A class of miniature probes has been proposed to supplant the fiber-optic probes used heretofore in some Raman and fluorescence spectroscopic systems. A probe according to the proposal would include a capillary tube coated with metal on its inside to make it reflective. A microlens would be hermetically sealed onto one end of the tube. A spectroscopic probe head would contain a single such probe, which would both deliver laser light to a sample and collect Raman or fluorescent light emitted by the sample.

  9. Gravimetric capillary method for kinematic viscosity measurements

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Iwan, J.; Alexander, D.; Jin, Wei-Qing

    1992-01-01

    A novel version of the capillary method for viscosity measurements of liquids is presented. Viscosity data can be deduced in a straightforward way from mass transfer data obtained by differential weighing during the gravity-induced flow of the liquid between two cylindrical chambers. Tests of this technique with water, carbon tetrachloride, and ethanol suggest that this arrangement provides an accuracy of about +/- 1 percent. The technique facilitates operation under sealed, isothermal conditions and, thus can readily be applied to reactive and/or high vapor pressure liquids.

  10. Paramecium swimming in a capillary tube

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Jung, Sunghwan

    2010-03-01

    Micro-organisms exhibit different strategies for swimming in complex environments. Many micro-swimmers such as paramecium congregate and tend to live near wall. We investigate how paramecium moves in a confined space as compared to its motion in an unbounded fluid. A new theoretical model based on Taylor's sheet is developed, to study such boundary effects. In experiments, paramecia are put inside capillary tubes and their swimming behavior is observed. The data obtained from experiments is used to test the validity of our theoretical model and understand how the cilia influence the locomotion of paramecia in confined geometries.

  11. Capillary Thinning of Particle-laden Drops

    NASA Astrophysics Data System (ADS)

    Wagoner, Brayden; Thete, Sumeet; Jahns, Matt; Doshi, Pankaj; Basaran, Osman

    2015-11-01

    Drop formation is central in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, a thinning filament is created between the about-to-form drop and the fluid hanging from the nozzle. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids. The thinning dynamics is, however, altered completely when the fluid contains particles, the physics of which is not well understood. In this work, we explore the impact of solid particles on filament thinning and drop formation by using a combination of experiments and numerical simulations.

  12. Capillary filling dynamics of water in nanopores

    NASA Astrophysics Data System (ADS)

    Bakli, Chirodeep; Chakraborty, Suman

    2012-10-01

    We portray a universal description of dynamic slip-stick behavior of water flowing through nanoscale pores. Based on fundamental molecular transport considerations, we derive a generalized constitutive model for describing resistive forces acting on the water column in a capillary that is being dynamically filled, as a combined function of the meniscus height, surface wettability, and roughness. This effectively acts like a unique signature of nanopore imbibition characteristics of water, which, when substituted in a simple one-dimensional force balance model agrees quantitatively with results from molecular dynamics simulations for a general class of problems, without necessitating the employment of any artificially tunable fitting parameters.

  13. Bacterial surface layer proteins as a novel capillary coating material for capillary electrophoretic separations.

    PubMed

    Moreno-Gordaliza, Estefanía; Stigter, Edwin C A; Lindenburg, Petrus W; Hankemeier, Thomas

    2016-06-01

    A novel concept for stable coating in capillary electrophoresis, based on recrystallization of surface layer proteins on hydrophobized fused silica capillaries, was demonstrated. Surface layer protein A (SlpA) from Lactobacillus acidophilus bacteria was extracted, purified and used for coating pre-silanized glass substrates presenting different surface wettabilities (either hydrophobic or hydrophilic). Contact angle determination on SlpA-coated hydrophobic silica slides showed that the surfaces turned to hydrophilic after coating (53 ± 5°), due to a protein monolayer formation by protein-surface hydrophobic interactions. Visualization by atomic force microscopy demonstrated the presence of a SlpA layer on methylated silica slides displaying a surface roughness of 0.44 ± 0.02 nm. Additionally, a protein layer was visualized by fluorescence microscopy in methylated silica capillaries coated with SlpA and fluorescein isothiocyanate-labeled. The SlpA-coating showed an outstanding stability, even after treatment with 20 mM NaOH (pH 12.3). The electroosmotic flow in coated capillaries showed a partial suppression at pH 7.50 (3.8 ± 0.5 10(-9) m(2) V(-1) s(-1)) when compared with unmodified fused silica (5.9 ± 0.1 10(-8) m(2) V(-1) s(-1)). To demonstrate the potential of this novel coating, the SlpA-coated capillaries were applied for the first time for electrophoretic separation, and proved to be very suitable for the isotachophoretic separation of lipoproteins in human serum. The separations showed a high degree of repeatability (absolute migration times with 1.1-1.8% coefficient-of-variation (CV) within a day) and 2-3% CV inter-capillary reproducibility. The capillaries were stable for more than 100 runs at pH 9.40, and showed to be an exceptional alternative for challenging electrophoretic separations at long-term use. PMID:27155306

  14. Comparison of three modifications of fused-silica capillaries and untreated capillaries for protein profiling of maize extracts by capillary electrophoresis.

    PubMed

    Pobozy, Ewa; Sentkowska, Aleksandra; Piskor, Anna

    2014-09-01

    In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused-silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω-iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated. It was found that for zeins separation, the most stable and efficient was the capillary coated with polyacrylamide. Finally, the usefulness of these methods was studied for the differentiation of zein fraction in transgenic and nontransgenic maize. Zeins extracted from maize standards containing 0 and 5% m/m genetic modification were successfully separated, but slight differences were observed in terms of the zein content. Albumin and globulin fractions were analyzed with the use of unmodified fused-silica capillary with borate buffer pH 9 and the capillary coated with polyacrylamide with phosphate buffer pH 3. In the albumin fraction, additional peaks were found in genetically modified samples. PMID:24931305

  15. Analysis of tear glucose concentration with electrospray ionization mass spectrometry.

    PubMed

    Taormina, Christopher R; Baca, Justin T; Asher, Sanford A; Grabowski, Joseph J; Finegold, David N

    2007-02-01

    We have developed a mass spectrometry-based method that allows one to accurately determine the glucose concentration of tear fluid. We used a 1 microL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 muL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting nondiabetic subject to be 13 to 51 microM while the onion-induced tear glucose concentration of a different nondiabetic subject to be 211 to 256 microM. PMID:17084090

  16. Analysis of Tear Glucose Concentration with Electrospray Ionization Mass Spectrometry

    PubMed Central

    Taormina, Christopher R.; Baca, Justin T.; Finegold, David N.; Asher, Sanford A.; Grabowski, Joseph J.

    2007-01-01

    We have developed a mass spectrometry-based method which allows one to accurately determine the glucose concentration of tear fluid. We used a 1 μL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 μL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting non-diabetic subject to be 13 to 51 μM while the onion-induced tear glucose concentration of a different non-diabetic subject to be 211 to 256 μM. PMID:17084090

  17. Linked Gas Chromatography/Fourier Transform Infrared Spectrometry/Fourier Transform Mass Spectrometry For Mixture Analysis

    NASA Astrophysics Data System (ADS)

    Laude, David A., Jr.; Johlman, Carolyn; Wilkins, Charles L.

    1985-12-01

    During the past few years it has been demonstrated that linkage of multiple spectrometry systems with gas chromatography (GC) offers significant advantages for structural analysis of mixture components as they are sepa-rated. In the work to be described, a Fourier transform mass spectrometer (FTMS) has been linked in parallel with a Fourier transform infrared (FTIR) spectrometer for concurrent analysis of GC eluants from a fused silica capillary column. This system provides FTIR, electron impact, and chemical ionization mass spectral analysis of each mixture component as it emerges from the GC. Furthermore, mass measurement accuracy in the low ppm range in the absence of calibrant is made possible by the FTMS. Effective use of the com-plementary information obtained is shown to produce more reliable analytical performance than for any individual measurement.

  18. Capillary electrophoresis of DNA for molecular diagnostics.

    PubMed

    Righetti, P G; Gelfi, C

    1997-09-01

    A number of applications of capillary zone electrophoresis (CZE) in sieving liquid polymers (notably linear polyacrylamides and cellulose) for the analysis of polymerase chain reaction (PCR) products of clinically relevant, diagnostic DNA, are reviewed. The fields covered are: human genetics, quantitative gene dosage, microbiology and virology, forensic medicine and therapeutic DNA (notably, antisense nucleotides). Some unique, novel developments are highlighted, such as: (i) nonisocratic CZE, i.e., temperature-programmed CZE for detection of DNA point mutations; (ii) the synthesis of novel N-substituted acrylamides, offering extreme resistance to alkaline hydrolysis coupled to high hydrophilicity. In the field of denaturing gradient gel electrophoresis (DGGE), as routinely performed in gel slabs, a novel methodology is described in CZE: double-gradient DGGE. In this technique, two gradients are simultaneously applied along the migration direction: a chemical (or thermal) denaturing gradient, for partially unwinding homo- and hetero-duplexes of DNA, and a porosity gradient, for recompacting diffuse bands melting over a broader range of denaturing conditions. It is thus demonstrated that chemical gradients, in addition to temperature gradients, can be easily implemented even in a capillary format. PMID:9372261

  19. Peptide separation in hydrophilic interaction capillary electrochromatography.

    PubMed

    Fu, Hongjing; Jin, Wenhai; Xiao, Hua; Huang, Haiwei; Zou, Hanfa

    2003-06-01

    Separation of small peptides by hydrophilic interaction capillary electrochromatography (HI-CEC) has been investigated. The negative surface charge of a hydrophilic, strong-cation-exchange stationary phase (PolySULFOETHYL A) provided a substantial cathodic electroosmotic flow (EOF). The influence of acetonitrile content, ionic strength, mobile phase pH as well as applied voltage on the migration of the peptides was studied. Possible retention mechanisms of the peptides in HI-CEC were discussed. It was found that hydrophilic interaction between the solutes and the stationary phase played a major role in this system, especially when mobile phases with high acetonitrile content were used. However, an ion-exchange mechanism and electrophoretic mobility also affect the migration of the peptides in HI-CEC. Elution order and selectivity was proved to be different in HI-CEC and capillary zone electrophoresis (CZE), thus revealing the potential of HI-CEC as a complementary technique to CZE for the separation of peptides. Efficiency and selectivity of HI-CEC for the separation of peptides were demonstrated by baseline separating nine peptides in 6 min. PMID:12858379

  20. Critical Velocity in Open Capillary Channel Flows

    NASA Technical Reports Server (NTRS)

    Rosendahl, Uwe; Dreyer, Michael E.; Rath, Hans J.; Motil, Brian; Singh, Bhim S. (Technical Monitor)

    2001-01-01

    We investigate forced liquid flows through open capillary channels with free surfaces experimentally. The experiments were performed under low gravity conditions in the Bremen Drop Tower and on board the sounding rocket TEXUS-37. Open capillary channels (vanes) are used in surface tension tanks to transport the propellant and to provide a flow path for the bubble-free liquid supply to the thrusters. Since the free surfaces can only withstand a certain pressure differential between the liquid and ambient, the flow rate in the channel is limited. The maximum flow rate is achieved when the surfaces collapse and gas is ingested into the outlet. Since experimental and theoretical data of this flow rate limitation is lacking, the safety factors for the application of vanes in surface tension tanks must be unnecessary high. The aim of the investigation is to determine the maximum liquid flow rate and the corresponding critical flow velocity. The characteristic nondimensional parameters, OHNESORGE number, and gap ratio, cover a wide range of usual vanes. For the theoretical approach a one-dimensional momentum balance was set up. The numerical solution yields the maximum volume flux and the position of the free surface in good agreement with the experiments.

  1. Capillary surface discontinuities above reentrant corners

    NASA Technical Reports Server (NTRS)

    Korevaar, H. J.

    1982-01-01

    A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.

  2. Analysis of spiramycin by capillary electrophoresis.

    PubMed

    González-Hernández, R; Li, Y M; Van Schepdael, A; Roets, E; Hoogmartens, J

    1999-09-01

    The development and validation of an analytical method for the determination of spiramycin I in the presence of its related substances by capillary electrophoresis is shown. The separation, performed in a phosphate buffer (80 mM, pH 7.5) containing 12 mM cetyltrimethylammonium bromide (CTAB) and 20 mM sodium cholate, with a 50 microm ID and 44 cm long fused-silica capillary (36 cm effective length), applying a voltage of 12 kV (l approximately 80 microA), at 25 degrees C, is achieved in 15 min. Good selectivity among spiramycin I and its related substances was obtained. The influence of the buffer pH, and of the CTAB and sodium cholate concentrations was investigated. The method robustness, examined by means of a full-fraction factorial design, shows that it can be used within the limits set for the three parameters that were investigated. The method is linear (r = 0.9992) and precise (day-to-day corrected peak area repeatability, n = 18, relative standard deviation = 1.3%). The limits of detection and quantitation are 7 pg (0.025%) and 22 pg (0.08%), respectively, relative to a 2 mg/mL solution. PMID:10499332

  3. Capillary wrinkling of thin bilayer polymeric sheets

    NASA Astrophysics Data System (ADS)

    Chang, Jooyoung; Menon, Narayanan; Russell, Thomas

    We have investigated capillary force induced wrinkling on a floated polymeric bilayer thin sheet. The origin of the wrinkle pattern is compressional hoop stress caused by the capillary force of a water droplet placed on the floated polymeric thin sheet afore investigated. Herein, we study the effect of the differences of surface energy arising from the hydrophobicity of Polystyrene (PS Mw: 97 K, Contact Angle: 88 º) and the hydrophilicity of Poly(methylmethacrylate) (PMMA Mw: 99K, Contact Angle: 68 º) on two sides of a bilayer film. We measure the number and the length of the wrinkles by broadly varying the range of thicknesses of top (9 nm to 550 nm) and bottom layer (25 nm to 330 nm). At the same, there is only a small contrast in mechanical properties of the two layers (PS E = 3.4 GPa, and PMMA E = 3 GPa). The number of the wrinkles is not strongly affected by the composition (PS(Top)/PMMA(Bottom) or PMMA(Top)/PS(Bottom)) and the thickness of each and overall bilayer system. However, the length of the wrinkle is governed by the contact angle of the drop on the top layer of bilayer system. We also compare this to the wrinkle pattern obtained in monolayer systems over a wide range of thickness from PS and PMMA (7 nm to 1 μm). W.M. Keck Foundation.

  4. Capillary Liquid Acquisition Device Heat Entrapment

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L. G.; Hastings, L. J.; Statham, G.; Turpin, J. B.

    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 subcooled 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.

  5. Computational modelling of microfluidic capillary breakup phenomena

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Sprittles, James; Oliver, Jim

    2013-11-01

    Capillary breakup phenomena occur in microfluidic flows when liquid volumes divide. The fundamental process of breakup is a key factor in the functioning of a number of microfluidic devices such as 3D-Printers or Lab-on-Chip biomedical technologies. It is well known that the conventional model of breakup is singular as pinch-off is approached, but, despite this, theoretical predictions of the global flow on the millimetre-scale appear to agree well with experimental data, at least until the topological change. However, as one approaches smaller scales, where interfacial effects become more dominant, it is likely that such unphysical singularities will influence the global dynamics of the drop formation process. In this talk we develop a computational framework based on the finite element method capable of resolving diverse spatio-temporal scales for the axisymmetric breakup of a liquid jet, so that the pinch-off dynamics can be accurately captured. As well as the conventional model, we discuss the application of the interface formation model to this problem, which allows the pinch-off to be resolved singularity-free, and has already been shown to produce improved flow predictions for related ``singular'' capillary flows.

  6. Capillary electrophoresis coupled with automated fraction collection.

    PubMed

    Huge, Bonnie Jaskowski; Flaherty, Ryan J; Dada, Oluwatosin O; Dovichi, Norman J

    2014-12-01

    A fraction collector based on a drop-on-demand ink-jet printer was developed to interface capillary zone electrophoresis with a 96 well microtiter plate. We first evaluated the performance of the collector by using capillary zone electrophoresis to analyze a 1mM solution of tetramethylrhodamine; a fluorescent microtiter plate reader was then used to detect the analyte and characterize fraction carryover between wells. Relative standard deviation in peak height was 20% and the relative standard deviation in migration time was 1%. The mean and standard deviation of the tetramethylrhodamine peak width was 5 ± 1 s and likely limited by the 4-s period between droplet deposition. We next injected a complex mixture of DNA fragments and used real-time PCR to quantify the product in a CE-SELEX experiment. The reconstructed electrophoretic peak was 27 s in duration. Finally, we repeated the experiment in the presence of a 30-µM thrombin solution under CE-SELEX conditions; fractions were collected and next-generation sequencing was used to characterize the DNA binders. Over 25,000 sequences were identified with close matches to known thrombin binding aptamers. PMID:25159411

  7. Using capillary electrophoresis to characterize polymeric particles.

    PubMed

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

    2016-09-01

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

  8. Capillary Electrophoresis coupled with Automated Fraction Collection

    PubMed Central

    Huge, Bonnie Jaskowski; Flaherty, Ryan; Dada, Oluwatosin O.; Dovichi, Norman J.

    2014-01-01

    A fraction collector based on a drop-on-demand ink-jet printer was developed to interface capillary zone electrophoresis with a 96 well microtiter plate. We first evaluated the performance of the collector by using capillary zone electrophoresis to analyze a 1 mM solution of tetramethylrhodamine; a fluorescent microtiter plate reader was then used to detect the analyte and characterize fraction carryover between wells. Relative standard deviation in peak height was 20% and the relative standard deviation in migration time was 1%. The mean and standard deviation of the tetramethylrhodamine peak width was 5 ± 1 s and likely limited by the 4-s period between droplet deposition. We next injected a complex mixture of DNA fragments and used real-time PCR to quantify the product in a CE-SELEX experiment. The reconstructed electrophoretic peak was 27 s in duration. Finally, we repeated the experiment in the presence of a 30-μM thrombin solution under CE-SELEX conditions; fractions were collected and next-generation sequencing was used to characterize the DNA binders. Over 25,000 sequences were identified with close matches to known thrombin binding aptamers. PMID:25159411

  9. Sounding rocket experiment on capillary channel flow

    NASA Astrophysics Data System (ADS)

    Rosendahl, U.; Fechtmann, C.; Dreyer, M. E.

    2005-08-01

    This paper is concerned with flow rate limitations in open capillary channels under low-gravity conditions. The channels consist of two parallel plates bounded by free liquid surfaces along the open sides. In the case of steady flow the capillary pressure of the free surface balances the differential pressure between the liquid and the surrounding constant-pressure gas phase. A maximum flow rate is achieved when the adjusted volumetric flow rate exceeds a certain limit leading to a collapse of the free surfaces. In order to investigate this type of flow an experiment aboard the sounding rocket TEXUS-41 was performed. The aim of the investigation was to achieve the profiles of the free liquid surfaces and to determine the maximum flow rate of the steady flow. For this purpose a new approach to the critical flow condition by enlarging the channel length was applied. The paper gives a review of the experimental set-up and the preparation of the flight procedures. Furthermore the experiment performance is described and the typical appearance of the flow indicated by its surface profiles is presented.

  10. Microfluidic Chip Coupled with Thermal Desorption Atmospheric Pressure Ionization Mass Spectrometry

    PubMed Central

    Chang, Chia-Hsien; Chen, Tsung-Yi; Chen, Yu-Chie

    2014-01-01

    Microfluidic chips have been used as platforms for a diversity of research purposes such as for separation and micro-reaction. One of the suitable detectors for microfluidic chip is mass spectrometry. Because microfluidic chips are generally operated in an open air condition, mass spectrometry coupled with atmospheric pressure ion sources can suit the requirement with minimum compromise. In this study, we develop a new interface to couple a microfluidic chip with mass spectrometry. A capillary tip coated with a layer of graphite, capable of absorbing energy of near-infrared (NIR) light is used to interface microfluidic chip with mass spectrometry. An NIR laser diode (λ=808 nm) is used to irradiate the capillary tip for assisting the generation of spray from the eluent of the microfluidic chip. An electrospray is provided to fuse with the spray generated from the microfluidic chip for post-ionization. Transesterification is used as the example to demonstrate the feasibility of using this interface to couple microfluidic chip with mass spectrometry. PMID:26839753

  11. X-Ray Spectrometry.

    ERIC Educational Resources Information Center

    Macdonald, G. L.

    1980-01-01

    Reviews instrumental developments and technique improvements in X-ray spectrometry, grouped into major topic areas of excitation, dispersion and detection, instrumentation and techniques, and quantitative analyses. Cites 162 references. (CS)

  12. Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

    ERIC Educational Resources Information Center

    Henriksson, Ulf; Eriksson, Jan Christer

    2004-01-01

    The thermodynamics of capillary rise is explained as the gravitational elevation of the whole column of liquid caused by the positive connection between the liquid, and the solid wall of the capillary tube. The curvature of the meniscus is ascribed to the maintenance of a physiochemical balance throughout the gravitational column of liquid.

  13. Capillary electrokinetic separations: Influence of mobile phase composition on performance

    SciTech Connect

    Sepaniak, M.J.; Swaile, D.F.; Powell, A.C.; Cole, R.O.

    1990-01-01

    The composition of the mobile phase employed in capillary zone electrophoresis and the related technique, micellar electrokinetic capillary chromatography, is an important factor in determining separation performance. The influences of ionic salt, surfactant, and organic solvent mobile phase additives on separation efficiency, retention, and elution range are discussed and demonstrated. 23 refs., 2 figs., 2 tabs.

  14. Capillary-Pumped Passive Reactor Concept for Space Nuclear Power

    SciTech Connect

    Dr. Thomas F. Lin; Dr. Thomas G. Hughes; Christopher G. Miller

    2008-05-30

    To develop the passively-cooled space reactor concept using the capillary-induced lithium flow, since molten lithium possesses a very favorable surface tension characteristic. In space where the gravitational field is minimal, the gravity-assisted natural convection cooling is not effective nor an option for reactor heat removal, the capillary induced cooling becomes an attractive means of providing reactor cooling.

  15. Assessing capillary flow on printed wiring board surfaces

    SciTech Connect

    Hosking, F.M.; Yost, F.G.; Hernandez, C.L.; Sackinger, S.J.

    1994-08-01

    A solderability test for evaluating capillary flow on printed wiring boards is presented. The test measures the flow of molten solder from a pad of fixed diameter onto attached strips of different widths. The technique simulates capillary flow behavior, including wetting kinetics, during typical electronics soldering. A flow model is proposed. Computational and experimental data are compared.

  16. A Simple Double-Source Model for Interference of Capillaries

    ERIC Educational Resources Information Center

    Hou, Zhibo; Zhao, Xiaohong; Xiao, Jinghua

    2012-01-01

    A simple but physically intuitive double-source model is proposed to explain the interferogram of a laser-capillary system, where two effective virtual sources are used to describe the rays reflected by and transmitted through the capillary. The locations of the two virtual sources are functions of the observing positions on the target screen. An…

  17. Rapid Screening of Complex Chemical Samples via Capillary Array Analysis

    SciTech Connect

    D. S. Anex; D. W. Neyer

    1998-11-01

    This report is a summary of the results of a two-year Laboratory-Directed Research and Development (LDRD) project that developed instrumentation and methods for capillary array analysis. During the course of this project, a new capillary array electrochromatography instrument was developed to perform eight simultaneous separations and provide complementary chromatographic information from each column on a single sample.

  18. Dynamics of monocytes flowing in a model pulmonary capillary bed

    NASA Astrophysics Data System (ADS)

    Viallat, Annie; Dupire, Jules; Adhesion and Inflammation lab Team

    2012-11-01

    The dynamics of blood cells in the pulmonary bed is an issue for tissue perfusion and host defense. The capillary segments in the lungs are smaller than the size of leukocytes so that most of them change their shape to enter and travel through a capillary pathway. During inflammation, changes in the cytoskeleton of leukocytes may stiffen them, resulting in their massive stop and sequestration within lung capillaries. However, due to difficulties of in vivo studies, little is known about the dynamics of leukocytes in the microcirculation and about the coupling between cellular rheology, capillary geometry and flow. We report the dynamics of monocytes (THP-1 cell line) flowing under constant pressure drop in a periodic network of capillaries that mimics the capillary bed. The analysis of cell entrance in the first segment allows the estimation of effective cellular elasticity, viscosity and cortical tension. Cells then present an unsteady regime, with a non-periodic trajectory, a stretching of their average shape and an increase of their velocity. This regime is interpreted from a parameter equivalent to the Deborah number of the system. Finally, a periodic regime is reached with alternatively left and right turns at capillary bifurcations. The reduced cell velocity is governed by an effective friction coefficient between the cell and the capillary walls. Both transient and final regimes depend on cell deformability, as shown by modifying the cortical actin of the cytoskeleton. This work has been supported by the French Research. National Agency (ANR) under reference ChipCellTrap.

  19. Further developments of capillary absorption spectrometers using small hollow-waveguide fibers

    SciTech Connect

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.; Kriesel, Jason M.

    2014-05-01

    Our objective is to enhance quantification of stable carbon and oxygen isotope ratios to better than 1‰ relative isotope precision for sample sizes < 1 pico-mole. A newer variant Capillary Absorption Spectrometer (CAS) is described using a proprietary linear-taper hollow waveguide in conjunction with wavelength and frequency modulation techniques of tunable laser absorption spectrometry. Previous work used circular capillaries with uniform 1 mm ID to measure 13C/12C ratios with ≥ 20 pico-mole samples to ≤ 10 ppm (1‰ precision against standards) [1]. While performing fairly well, it generated residual modal noise due to multipath propagation in the hollow-waveguides (HWGs). This system has been utilized with laser ablation-catalytic combustion techniques to analyze small resolution (~ 25 μm spot diameter) laser ablation events on solids. Using smaller ID capillary waveguides could improve detection limits and spatial resolutions. Reducing an IR compatible hollow waveguide’s inner diameter (ID) to < 300 μm, reduces modal noise significantly for mid-IR operation, but feedback noise with high gain semiconductor lasers can become problematic. A proprietary linear-taper small waveguide (mean ID = 0.35 mm, L = 1 m) was tested to understand whether modal noise and optical feedback effects could be simultaneously reduced. We see better mode filtering and, significant reductions of feedback noise under favorable coupling of a multi-spatial mode QC laser to the smaller ID of the linear-tapered HWG. We demonstrate that better modal coupling operation is consistent with Liouville’s theorem, where greater suppression of feedback from spurious scatter within the HWG occurs by injecting the laser into the smaller ID port. Our progress on developing lighter weight, potentially fieldable alternatives to Isotope Ratio Mass Spectrometers (IRMS) with a small volume (≤ 0.1 cm3) CAS system will be discussed and compared to other competitive systems.

  20. Analysis of fatty oil in Semen Ziziphi Spinosae by capillary gas chromatography.

    PubMed

    Yu-Juan, Li; Kai-Shun, Bi; Xin-Miao, Liang; Hong-Bin, Xiao

    2003-01-01

    A simple and fast capillary gas chromatographic (CGC) method with flame ionization detection is developed for the analysis of fatty oil in Semen Ziziphi Spinosae. After methyl-esterification, eight components are identified by gas chromatography-mass spectrometry. The derivatization condition is investigated in order to validate this method. Palmitic acid and stearic acid are quantitated simultaneously. The limits of detection are 5.024 microg/mL for palmitic acid and 6.957 microg/mL for stearic acid, respectively. The limits of quantitation are 16.76 microg/mL for palmitic acid and 23.19 microg/mL for stearic acid, respectively. The percent recoveries of palmitic and stearic acid are 97.4% and 96.6%. CGC is shown to be a quick and informative tool for the analysis of fatty oil in Semen Ziziphi Spinosae. PMID:12597596