WorldWideScience

Sample records for capillary electrophoretic analysis

  1. Capillary Electrophoretic Analysis of Classical Organic Pollutants.

    Science.gov (United States)

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

    2016-01-01

    The synthesis and usage of a wide range of organic compounds have shown a considerable increase in the past few decades. Many of these compounds are potential pollutants for the environment. They differ from each other in their chemical structure and properties. Correspondingly different separation strategies are required for their separation. There is need to assess the human exposure to these chemicals and to identify and develop analytical methods for their identification. In this chapter we have presented some methods for the separation and the analysis of the organic pollutants like dyes, phenolic pollutants, phthalates, endocrine disrupting chemicals, polycyclic aromatic hydrocarbon, explosives, agricultural pesticides, and toxins. PMID:27645747

  2. Study on the Interaction between Strychnine and Bovine Serum Albumin by Capillary Electrophoretic Frontal Analysis

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The protein binding constant, binding sites of the Strychnos alkaloid-strychnine and bovine serum albumin (BSA) was determined by capillary electrophoretic frontal analysis (CE-FA)for the first time. The experiment was carried out in a polyacrylamide-coated fused silica capillary (48.4 cm×50 μm i.d., 38.1 cm effective length) with 20 mmol/L citrate/MES buffer (pH 6.0, ionic strength 0.17). The applied voltage was 12 kV and detection wavelength was set at 257nm. The plateau height of the peak was employed to determine the unbound concentration of drug in BSA equilibrated sample solution based on the external drug standard in the absence of protein. The present method provides a convenient, accurate technique for the early stage of drug screening.

  3. Capillary electrophoretic study on UDP-sugars in cells

    Institute of Scientific and Technical Information of China (English)

    许国旺; R.Lehmann; 路鑫; H.M.Liebich; 张玉奎; 卢佩章

    2000-01-01

    Glucose is an important regulator of cell growth and metabolism. Uridine diphosphate sugars (UDP-sugars), as the intermediate products of metabolism, play pivotal roles as precursors in the synthesis of complex carbohydrates and glycolipids as well as lectose. It is very important to study their metabolism in cells in clinical biochemistry. A capillary electrophoretic method has been developed for the analysis of UDP-sugars and nucleotides. By using an uncoated capillary (70cm×50μm) and 20 mmol/L borax buffer (pH 9), 4 important UDP-sugars can be analyzed in 15 min at 22 kV with satisfactory precision and sensitivity. The developed method has been applied to analyze UDP-sugars concentrations in lymphocytes, fibroblasts and mesangial cells, and the results show it not only is much better than HPLC method, but also can be used to measure the energy charge of cells.

  4. Capillary electrophoretic study on UDP-sugars in cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Glucose is an important regulator of cell growth and metabolism. Uridine diphosphate sugars (UDP-sugars), as the intermediate products of metabolism, play pivotal roles as precursors in the synthesis of complex carbohydrates and glycolipids as well as lectose. It is very important to study their metabolism in cells in clinical biochemistry. A capillary electrophoretic method has been developed for the analysis of UDP-sugars and nucleotides. By using an uncoated capillary (70cm×50 μm) and 20 mmol/L borax buffer (pH 9), 4 important UDP-sugars can be analyzed in 15 min at 22 kV with satisfactory precision and sensitivity. The developed method has been applied to analyze UDP-sugars concentrations in lymphocytes, fibroblasts and mesangial cells, and the results show it not only is much better than HPLC method, but also can be used to measure the energy charge of cells.

  5. New methodology for capillary electrophoresis with ESI-MS detection: Electrophoretic focusing on inverse electromigration dispersion gradient. High-sensitivity analysis of sulfonamides in waters.

    Science.gov (United States)

    Malá, Zdena; Gebauer, Petr; Boček, Petr

    2016-09-01

    This article describes for the first time the combination of electrophoretic focusing on inverse electromigration dispersion (EMD) gradient, a new separation principle described in 2010, with electrospray-ionization (ESI) mass spectrometric detection. The separation of analytes along the electromigrating EMD profile proceeds so that each analyte is focused and concentrated within the profile at a particular position given by its pKa and ionic mobility. The proposed methodology combines this principle with the transport of the focused zones to the capillary end by superimposed electromigration, electroosmotic flow and ESI suction, and their detection by the MS detector. The designed electrolyte system based on maleic acid and 2,6-lutidine is suitable to create an inverse EMD gradient of required properties and its components are volatile enough to be compatible with the ESI interface. The characteristic properties of the proposed electrolyte system and of the formed inverse gradient are discussed in detail using calculated diagrams and computer simulations. It is shown that the system is surprisingly robust and allows sensitive analyses of trace amounts of weak acids in the pKa range between approx. 6 and 9. As a first practical application of electrophoretic focusing on inverse EMD gradient, the analysis of several sulfonamides in waters is reported. It demonstrates the potential of the developed methodology for fast and high-sensitivity analyses of ionic trace analytes, with reached LODs around 3 × 10(-9) M (0.8 ng mL(-1)) of sulfonamides in spiked drinking water without any sample pretreatment. PMID:27543034

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

    OpenAIRE

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

    2015-01-01

    Purpose: The aim of the study was the characterization of the electrophoretic behavior of cephalosporins from different generation having different structural characteristics in order to develop a rapid, simple and efficient capillary electrophoretic method for their identification and simultaneous separation from complex mixtures. Methods: Ten cephalosporin derivatives (cefaclor, cefadroxil, cefalexin, cefazolin, cefoxitin, cefuroxime, cefoperazone, cefotaxime, ceftazidime, ce...

  7. Electrophoretic Focusing: An Alternative to Capillary Electrophoresis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrophoretic focusing is a new separation method intended to achieve high resolution within very short sample residence times because one fraction is separated...

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

    Directory of Open Access Journals (Sweden)

    Gabriel Hancu

    2015-06-01

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

  9. Increasing conclusiveness of metabonomic studies by chem-informatic preprocessing of capillary electrophoretic data on urinary nucleoside profiles.

    Science.gov (United States)

    Szymańska, E; Markuszewski, M J; Capron, X; van Nederkassel, A-M; Heyden, Y Vander; Markuszewski, M; Krajka, K; Kaliszan, R

    2007-01-17

    Nowadays, bioinformatics offers advanced tools and procedures of data mining aimed at finding consistent patterns or systematic relationships between variables. Numerous metabolites concentrations can readily be determined in a given biological system by high-throughput analytical methods. However, such row analytical data comprise noninformative components due to many disturbances normally occurring in analysis of biological samples. To eliminate those unwanted original analytical data components advanced chemometric data preprocessing methods might be of help. Here, such methods are applied to electrophoretic nucleoside profiles in urine samples of cancer patients and healthy volunteers. The electrophoretic nucleoside profiles were obtained under following conditions: 100 mM borate, 72.5 mM phosphate, 160 mM SDS, pH 6.7; 25 kV voltage, 30 degrees C temperature; untreated fused silica capillary 70 cm effective length, 50 microm I.D. Different most advanced preprocessing tools were applied for baseline correction, denoising and alignment of electrophoretic data. That approach was compared to standard procedure of electrophoretic peak integration. The best results of preprocessing were obtained after application of the so-called correlation optimized warping (COW) to align the data. The principal component analysis (PCA) of preprocessed data provides a clearly better consistency of the nucleoside electrophoretic profiles with health status of subjects than PCA of peak areas of original data (without preprocessing).

  10. Capillary Electrophoretic Immunoassay with Laser-induced Fluorescence Detection for Interferon-gamma

    Institute of Scientific and Technical Information of China (English)

    Hua ZHANG; Hai Ming WEI; Wen Rui JIN

    2004-01-01

    Capillary electrophoretic immunoassay with laser-induced fluorescence detection for recombinant human interferon-gamma (IFN-γ) was established. The limits of detection for three forms of IFN-γare 6.9 ng/L, 5.7 ng/L and 5.0 ng/L, respectively.

  11. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Árpád Gyéresi

    2013-02-01

    Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  12. Ligand-substitution mode capillary electrophoretic reactor: extending capillary electrophoretic reactor toward measurement of slow dissociation kinetics with a half-life of hours.

    Science.gov (United States)

    Iki, Nobuhiko; Takahashi, Mariko; Takahashi, Toru; Hoshino, Hitoshi

    2009-09-15

    A method employing capillary electrophoresis (CE) was developed to determine the rate constant of the very slow spontaneous dissociation of a complex species. The method uses a CE reactor (CER) to electrophoretically separate components from a complex zone and, thus, spontaneously dissociate a complex. The dissociation is accelerated by ligand substitution (LS) involving a competing ligand added to the electrophoretic buffer. The LS-CER method is validated using the dissociation of a Ti(IV)-catechin complex and EDTA as a competing ligand. There is good agreement between the spontaneous dissociation rate constant (k(d) = (1.64 +/- 0.63) x 10(-4) s(-1)) and the rate constant obtained by a conventional batchwise LS reaction (k(d) = (1.43 +/- 0.04) x 10(-4) s(-1)). Furthermore, the usefulness of the method is demonstrated using a Ti(IV)-tiron complex, for which k(d) = (0.51 +/- 0.43) x 10(-4) s(-1), corresponding to a half-life (t(1/2)) of 3.8 h. Notably, a single run of LS-CER for the Ti(IV) complex is completed within 40 min, implying that LS-CER requires a considerably shorter measurement time (roughly equal to t(1/2)) than conventional CER. LS-CER can be widely applied to determine the spontaneous dissociation rates of inorganic diagnostic and therapeutic reagents as well as of biomolecular complexes.

  13. Current role of capillary electrophoretic/electrokinetic techniques in forensic toxicology.

    Science.gov (United States)

    Tagliaro, Franco; Bortolotti, Federica; Pascali, Jennifer P

    2007-08-01

    The current application of capillary electrophoresis in forensic toxicology has been critically reviewed with special focus on the areas where this technique has shown real advantages over chromatographic methods. For example, capillary electrophoresis has been most successfully applied to the chiral analysis of some drugs of forensic interest, including amphetamines and their congeners. Another typical application field of capillary electrophoresis is represented by protein analysis. Recently, special interest has been paid to carbohydrate deficient transferrin (CDT), the most important biological marker of chronic alcohol abuse. Other specific applications of capillary electrophoresis of potential forensic toxicological concern are also discussed. The review includes 62 references. PMID:17572886

  14. Correlation between Molecular Structures and Relative Electrophoretic Mobility in Capillary Electrophoresis: Alkylpyridines

    Institute of Scientific and Technical Information of China (English)

    YAO, Xiao-Jun; FAN, Bo-Tao; DOUCET, J. P.; PANAYE, A.; LIU, Man-Cang; ZHANG, Rui-Sheng; HU, Zhi-De

    2003-01-01

    The quantitative relationship between relative electrophoretic mobility in capillary electrophoresis for a series of 31 closely related alkylpyridines and their molecular structures was studied by using CODESSA. According to the t-test on the results, we found that the three most important descriptors affecting the mobility are the relative number of rings (NR), Min e-n attraction for a C-N bond (MEN) and average complementary information index (ACIC). With these structure descriptors a good three-parameter linear model was developed to correlate the mobility of these compounds with their structures. This model can not only correctly predict the migration behavior of these compounds, but also find the structural factors which are responsible for the migration behavior of these compounds,thus can help to explain the separation mechanism of these compounds. The method used in this work can also be extended to the mobility-structure relationship research of other compounds.

  15. Capillary electrophoretic-ultraviolet method for the separation and estimation of zineb, maneb, and ferbam in food samples.

    Science.gov (United States)

    Aulakh, Jatinder Singh; Fekete, Agnes; Malik, Ashok Kumar; Mahajan, Rakesh Kumar; Schmitt-Kopplin, Philippe

    2007-01-01

    A simple and sensitive capillary electrophoretic method with ultraviolet detection has been developed for the separation and determination of ferbam [iron(III)-dimethyldithiocarbamate], maneb [manganese(II)-ethylenebisdithiocarbamate] and zineb [zinc(II)-ethylenebisdithiocarbamate], in borate buffer, after their acidic decomposition and complexation with CDTA (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid monohydrate), as CDTA-metal complexes of Fe+3, Mn +2, and Zn+2. The determination is dependent on the pH and the nature of the buffer solutions. In this method, the detection limit (signal-to-noise ratio = 3) is 0.0013, 0.0022, and 0.0023 mM for ferbam, maneb, and zineb, respectively. The relative standard deviation for the analysis of 1 mM of each was found to be 1.5 +/- 0.2%. The method was successfully applied for the analysis of red beans and grain samples spiked with ferbam, maneb, and zineb. The applicability of capillary electrophoresis as a useful tool for the simultaneous determination and analysis of ferbam, maneb, and zineb is demonstrated. PMID:17580637

  16. Capillary electrophoretic behaviors of pharmacologically active xanthones from Securidaca inappendiculata with beta-cyclodextrin as a buffer additive.

    Science.gov (United States)

    Bo, Tao; Huang, Yongfa; Yang, Xuedong; Li, Ke An; Liu, Huwei; Xu, Lizhen

    2003-04-01

    The capillary electrophoretic (CE) behaviors of ten xanthones in the presence of beta-cyclodextrin (CD) are investigated, and apparent analyte-selector binding constants between beta-CD and the xanthones in the CE running buffer are calculated to elucidate the migration order. Also, the separation selectivity with beta-CD additive is compared with that of sulfated beta-CD additive. It is indicated that beta-CD can greatly change the separation selectivity of xanthones, and the electrophoretic behaviors of xanthones are rather different when using beta-CD from that when using sulfated beta-CD as an additive. PMID:12803804

  17. Metal Ions Analysis with Capillary Zone Electrophoresis.

    Science.gov (United States)

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

    2016-01-01

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

  18. Capillary electrophoretic study of thiolated alpha-cyclodextrin-capped gold nanoparticles with tetraalkylammonium ions.

    Science.gov (United States)

    Paau, Man Chin; Lo, Chung Keung; Yang, Xiupei; Choi, Martin M F

    2009-11-27

    Capillary zone electrophoresis (CZE) has been employed to characterize nanometer-sized thiolated alpha-cyclodextrin-capped gold nanoparticles (alpha-CD-S-AuNPs). The addition of tetrabutylammonium (Bu(4)N(+)) ions to the run buffer greatly narrows the migration peak of alpha-CD-S-AuNP. The optimal run buffer was determined to be 10mM Bu(4)N(+) in 30 mM phosphate buffer at pH 12 and an applied voltage of 15 kV. The effect of various tetraalkylammonium ions on the peak width and electrophoretic mobility (mu(e)) of alpha-CD-S-AuNP was studied in detail. Bu(4)N(+) ions assist in inter-linking the alpha-CD-S-AuNPs and narrowing the migration peak in CZE. This observation can be explained by the fact that each Bu(4)N(+) ion can simultaneously interact with several hydrophobic cavities of the surface-attached alpha-CDs on AuNPs. The TEM images show that alpha-CD-S-AuNPs with Bu(4)N(+) are linked together but in the absence of Bu(4)N(+), they are more dispersed. The migration mechanism in CZE is based on the formation of inclusion complexes between Bu(4)N(+) and alpha-CD-S-AuNPs which induces changes in the charge-to-size ratio of alpha-CD-S-AuNPs and mu(e). An inverse linear relationship (r(2)>0.998) exists between the mu(e) and size of alpha-CD-S-AuNPs in the core range 1.4-4.1 nm. The CZE analyses are rapid with migration time less than 4 min. A few nanoliters of each of the alpha-CD-S-AuNP samples were injected hydrodynamically at 0.5 psi for 5s. Our work confirms that CZE is an efficient tool for characterizing the sizes of alpha-CD-S-AuNPs using Bu(4)N(+) ions. PMID:19853853

  19. Capillary electrophoretic determination of antimigraine formulations containing caffeine, ergotamine, paracetamol and domperidone or metoclopramide.

    Science.gov (United States)

    Sultan, Maha A; Maher, Hadir M; Alzoman, Nora Z; Alshehri, Mona M; Rizk, Mohamed S; Elshahed, Mona S; Olah, Ileana V

    2013-07-01

    A novel, fast, sensitive and specific technique using capillary electrophoresis coupled to a diode array detector has been developed for the separation and simultaneous determination of two antimigraine mixtures in tablet formulation. The two combinations are ergotamine tartrate (ERG), caffeine (CAF) and paracetamol (PAR) with either domperidone (DOM), combination (I) or metoclopramide (MET), combination (II). The proposed method utilized a fused silica capillary (55 cm × 75 µm i.d.) and background electrolyte composed of phosphate buffer (25 mM, pH 9.8). The separation was achieved at 20 KV applied voltage and at 25°C. The described method was linear over the range of 1-80 and 2-100 µg/mL for CAF and MET, respectively, and 1-80 µg/mL for DOM, ERG and PAR. Intra-day and inter-day relative standard deviation (n = 5) was ≤1.10%. The limits of detection of CAF and PAR were 0.20 and 0.10 µg/mL, respectively, and 0.50 µg/mL for MET, DOM and ERG. Other aspects of analytical validation were also evaluated. The proposed method was successfully applied to the analysis of the two combinations in their tablets. Therefore, the proposed method is suitable for the routine control of these ingredients in multicomponent dosage forms. PMID:23180758

  20. Rational use of stacking principles for signal enhancement in capillary electrophoretic separations of poliovirus samples.

    Science.gov (United States)

    Oita, Iuliana; Halewyck, Hadewych; Pieters, Sigrid; Dejaegher, Bieke; Thys, Bert; Rombaut, Bart; Vander Heyden, Yvan

    2011-04-28

    The use of an earlier developed capillary electrophoresis (CE) method, either to investigate poliovirus (PV) samples with a low viral-purity level or to study the less abundant sub-viral particles, revealed the necessity for an intra-column signal enhancement strategy. Although intra-column signal enhancement is a very popular approach to assay small molecules, it is less straightforward for the analysis of biological macromolecules or particles. A reason could be that, for a proper signal enhancement approach, these samples have to be thoroughly studied to understand the factors affecting the separation process. For the investigated PV samples, a screening design revealed that injecting larger sample plugs significantly enhanced the analytical signal, but also significantly decreased the separation efficiency. A subsequently executed central composite design determined the largest sample plug that can be injected without compromising the separation. Finally, the sample dilution and the length of the injected plug were used for tuning the intensity of the analytical response. Two combinations of sample dilution and injected plug size, at extreme values, were investigated in detail to define the best procedure for PV analysis using CE. In both situations, PV was effectively separated and quantified in rather complex samples, showing a good repeatability, an acceptable linearity for the PV particles and a decreased limit of detection in comparison with the existing method. In conclusion, intra-column signal enhancement can be successfully applied for viral suspensions, extending the applicability of CE methods to samples with lower virus concentrations, and/or allowing a significant reduction in the minimum required volume of sample. For PV samples, 5μl of sample is necessary instead of the previous 20μl, while the analytical signal was enhanced up to 14 times. The results of this study can provide a basis for the development of routine CE methods for viral

  1. Capillary electrophoretic study of individual exocytotic events in single mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ho, A.M.W.

    1999-02-12

    The peak profile of individual degranulation events from the on-column release of serotonin from single rat peritoneal mast cells (RPMCs) was monitored using capillary electrophoresis with laser-induced native fluorescence detection (CE-LINF). Serotonin, an important biogenic amine, is contained in granules (0.25 fL) within RPMCs and is extruded by a process termed exocytosis. The secretagogue, Polymyxin B sulfate, was used as the CE running buffer after injection of a single RPMC into the separation capillary to stimulate the release of the granules. Because the release process occurs on a ms time scale, monitoring individual exocytotic events is possible with the coupling of high-speed CE and LINF detection.

  2. Inter-instrumental method transfer of chiral capillary electrophoretic methods using robustness test information.

    Science.gov (United States)

    De Cock, Bart; Borsuk, Agnieszka; Dejaegher, Bieke; Stiens, Johan; Mangelings, Debby; Vander Heyden, Yvan

    2014-08-01

    Capillary electrophoresis (CE) is an electrodriven separation technique that is often used for the separation of chiral molecules. Advantages of CE are its flexibility, low cost and efficiency. On the other hand, the precision and transfer of CE methods are well-known problems of the technique. Reasons for the more complicated method transfer are the more diverse instrumental differences, such as total capillary lengths and capillary cooling systems; and the higher response variability of CE methods compared to other techniques, such as liquid chromatography (HPLC). Therefore, a larger systematic change in peak resolutions, migration times and peak areas, with a loss of separation and efficiency may be seen when a CE method is transferred to another laboratory or another type of instrument. A swift and successful method transfer is required because development and routine use of analytical methods are usually not performed in the same laboratory and/or on the same type of equipment. The aim of our study was to develop transfer rules to facilitate CE method transfers between different laboratories and instruments. In our case study, three β-blockers were chirally separated and inter-instrumental transfers were performed. The first step of our study was to optimise the precision of the chiral CE method. Next, a robustness test was performed to identify the instrumental and experimental parameters that were most influencing the considered responses. The precision- and the robustness study results were used to adapt instrumental and/or method settings to improve the transfer between different instruments. Finally, the comparison of adapted and non-adapted transfers allowed deriving some rules to facilitate CE method transfers.

  3. Study of nucleic acid-ligand interactions by capillary electrophoretic techniques: A review.

    Science.gov (United States)

    Neaga, I O; Bodoki, E; Hambye, S; Blankert, B; Oprean, R

    2016-01-01

    The understanding of nucleic acids-ligand (proteins, nucleic acids or various xenobiotics) interactions is of fundamental value, representing the basis of complex mechanisms that govern life. The development of improved therapeutic strategies, as well as the much expected breakthroughs in case of currently untreatable diseases often relies on the elucidation of such biomolecular interactions. Capillary electrophoresis (CE) is becoming an indispensable analytical tool in this field of study due to its high versatility, ease of method development, high separation efficiency, but most importantly due to its low sample and buffer volume requirements. Most often the availability of the compounds of interest is severely limited either by the complexity of the purification procedures or by the cost of their synthesis. Several reviews covering the investigation of protein-protein and protein-xenobiotics interactions by CE have been published in the recent literature; however none of them promotes the use of these techniques in the study of nucleic acid interactions. Therefore, various CE techniques applicable for such interaction studies are discussed in detail in the present review. The paper points out the particular features of these techniques with respect the estimation of the binding parameters, in analytical signal acquisition and data processing, as well as their current shortcomings and limitations.

  4. Chromatographic and electrophoretic methods for nanodisc purification and analysis

    DEFF Research Database (Denmark)

    Justesen, Bo Højen; Günther-Pomorski, Thomas

    2014-01-01

    of proper reconstitution are still major challenges during the sample preparation. This review gives an overview of the methods used for purifying and analyzing nanodiscs and nanodisc-reconstituted membrane proteins, with an emphasis on the chromatographic and electrophoretic approaches....

  5. Analysis of Small Ions with Capillary Electrophoresis.

    Science.gov (United States)

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

    2016-01-01

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

  6. Capillary electrophoretic separation of humic substances using hydroxyethyl cellulose as a buffer additive and its application to characterization of humic substances in a river water sample.

    Science.gov (United States)

    Takahashi, Toru; Kawana, Jun; Hoshino, Hitoshi

    2009-01-01

    We have developed a concise tool for the investigation of the transition of humic substances in environmental water. The separation of water-soluble humic substances was achieved rapidly and effectively by capillary electrophoresis using a polyacrylamide-coated capillary and a phosphate electrophoretic buffer solution (pH 7.0) containing hydroxyethyl cellulose. The separation mechanism was assessed using the ultrafiltration technique. The effect of the complexation of humic substances with metal ions was studied by using the proposed method. When Fe(III) ions or EDTA was added to the sample solution of fulvic acid, a distinct change in the electropherogram pattern based on the conformational change of fulvic acid was observed. The successful application of the proposed method to the characterization of humic substances in a river water sample was also demonstrated.

  7. Classification of Spanish white wines using their electrophoretic profiles obtained by capillary zone electrophoresis with amperometric detection.

    Science.gov (United States)

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

    2014-06-01

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

  8. Improved Peak Capacity for Capillary Electrophoretic Separations of Enzyme Inhibitors with Activity-Based Detection Using Magnetic Bead Microreactors

    OpenAIRE

    Yan, Xiaoyan; Gilman, S. Douglass

    2010-01-01

    A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using NdFeB magnet(s) to immobilize alkaline phosphatase-coated superparamagnetic beads (2.8 μm diameter) inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with the substrate, AttoPhos. Product generated in the enzyme ...

  9. Application of a new capillary electrophoretic method for the determination of carbohydrates in forensic, pharmaceutical, and beverage samples.

    Science.gov (United States)

    Sarazin, Cédric; Delaunay, Nathalie; Costanza, Christine; Eudes, Véronique; Gareil, Pierre

    2012-09-15

    A new capillary electrophoresis method dedicated to the analysis of neutral underivatized carbohydrates was recently developed by our group. It involved a background electrolyte composed of 98 mM NaOH and 120 mM NaCl, and direct UV detection via the formation of an absorbing intermediate in the detection window by photooxidation. This article focuses on the validation of this method for the determination of fructose, glucose, lactose, and sucrose in forensic, pharmaceutical, and beverage samples. Intermediate precisions were about 2.3% for normalized corrected peak areas and 1.8% for normalized migration times using naphthalenesulfonate as internal standard. Limits of detection varying from 5 μM for sucrose and lactose to 7 μM for glucose and 10 μM for fructose were obtained. Potential matrix effects were statistically studied for soil, cloth, plastic, cotton, red wine, and with simulated iron, calcium, and sucrose-based matrices, containing various inorganic anions and cations, sometimes at high levels. No significant matrix effect was observed. Finally, analyses of real post-explosion residues, smoke device, cough syrup, red wine, and apple juice were successfully performed. PMID:22967542

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

    Science.gov (United States)

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

    2016-04-22

    Glycoproteins expressed in the human body can experience modifications as result of pathological situations. Detection of those changes can be useful as disease biomarkers. As a result of these modifications, size and/or electrical charge of the glycoprotein can be altered. Migration in capillary zone electrophoresis (CZE) is governed by the size to charge ratio of the analyte and therefore this separation technique can be used to monitor those modifications. At its turn, the alteration of the electrophoretical pattern of a given glycoprotein could be used as disease biomarker. To this aim, high repeatability for separation of a large number of peaks for a given glycoprotein is desirable. For prostate cancer, new markers are needed to decrease the high number of false positive results provided by the biomarkers currently used in clinics. In this sense, CZE methods for analysis of the several prostate specific antigen (PSA) peaks which this glycoprotein exhibit, called isoforms and containing one or more glycoforms, could be useful to study the PSA pattern as prostate cancer marker. In this study two complementary strategies to achieve both lot-to-lot capillary repeatability and high resolution of a large number of PSA isoforms are developed. Better performance and precision have been obtained for capillaries conditioned with HCl than for those conditioned with NaOH. Optimization of the background electrolyte (BGE) pH value to 8.0 and inclusion of 3M urea on its composition were the two factors of highest impact for enhancing resolution of the highest number of PSA peaks. Under the optimized conditions for capillary conditioning and BGE pH and composition, long-term resolution of 10 isoforms of PSA was achieved. Inter-day (n=3) %RSD was 0.55 for the ratio tm/tEOF, 1.15 for μeff, and 5.02 for % Acorr of the PSA peaks. PMID:27018191

  11. Capillary electrophoretic methods in the development of metal-based therapeutics and diagnostics: new methodology and applications.

    Science.gov (United States)

    Bytzek, Anna K; Hartinger, Christian G

    2012-02-01

    In recent years, capillary electrophoresis (CE) has matured to a standard method in medicinal inorganic chemistry. More and more steps of the drug discovery process are followed by CE. However, not only the number of applications has steadily increased but also the variety of used methodology has significantly broadened and, as compared to a few years ago, a wider scope of separation modes and hyphenated systems has been used. Herein, a summary of the newly utilized CE methods and their applications in metallodrug research in the timeframe 2006-2011 is presented, following related reviews from 2003 and 2007 (Electrophoresis, 2003, 24, 2023-2037; Electrophoresis 2007, 28, 3436-3446). Areas covered include impurity profiling, quality control of pharmaceutical formulations, lipophilicity estimation, interactions between metallodrugs and proteins or nucleotides, and characterization and also quantification of metabolites in biological matrices and real-world samples.

  12. Serum proteins analysis by capillary electrophoresis

    OpenAIRE

    Uji, Yoshinori; Okabe, Hiroaki

    2001-01-01

    The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of...

  13. Analysis of a Common Cold Virus and Its Subviral Particles by Gas-Phase Electrophoretic Mobility Molecular Analysis and Native Mass Spectrometry

    NARCIS (Netherlands)

    Weiss, Victor U.; Bereszcazk, Jessica Z.; Havlik, Marlene; Kallinger, Peter; Gösler, Irene; Kumar, Mohit; Blaas, Dieter; Marchetti-Deschmann, Martina; Heck, Albert J R; Szymanski, Wladyslaw W.; Allmaier, Günter

    2015-01-01

    Gas-phase electrophoretic mobility molecular analysis (GEMMA) separates nanometer-sized, single-charged particles according to their electrophoretic mobility (EM) diameter after transition to the gas-phase via a nano electrospray process. Electrospraying as a soft desorption/ionization technique pre

  14. A capillary electrophoretic study on the specificity of beta-galactosidases from Aspergillus oryzae, Escherichia coli, Streptococcus pneumoniae, and Canavalia ensiformis (jack bean).

    Science.gov (United States)

    Zeleny, R; Altmann, F; Praznik, W

    1997-03-01

    The specificities of the beta-galactosidases from Aspergillus oryzae, Escherichia coli, Streptococcus pneumoniae, and Canavalia ensiformis (jack bean) have been studied by capillary zone electrophoresis. Various di- and oligosaccharides as well as a biantennary asialo N-glycan were used as substrates. Following enzymatic hydrolysis, the mixtures of substrates and products were derivatized with ethyl 4-aminobenzoate and separated by high-performance capillary electrophoresis in a borate buffer system using uv detection. Baseline separation of the respective peaks was obtained in 4 min, allowing the analysis of a large number of samples. Therefore, initial rates of hydrolysis could be determined. The beta-galactosidase from A. oryzae exhibited minimal activity toward Galbeta1-3GlcNAc. In contrast to the enzyme from S. pneumoniae which is almost specific for beta1-4 linkages, the Aspergillus galactosidase readily hydrolyzed Galbeta1-4GlcNAc and Galbeta1-6GlcNAc. Neither of the four beta-galactosidases acted upon Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4Gl c (lacto-N-fucopentaose III) even though the corresponding nonfucosylated oligosaccharides were good substrates. With the exception of the enzyme from E. coli, the beta-galactosidases degalactosylated a biantennary N-linked oligosaccharide. PMID:9056188

  15. Analysis of organic acids in Macedonian wines by capillary electrophoresis

    OpenAIRE

    Jancovska, Maja; Ivanova, Violeta; Gulaboski, Rubin; Belder, Detlev

    2013-01-01

    Capillary electrophoresis as a separation technique can be applied for analysis of organic acids in white and red wines, providing high resolution separation of the analytes. Organic acids such as of tartaric, malic, lactic citric and succinic acids have been analysed in many Macedonian red and white wines by capillary electrophoresis, and results have been discussed.

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

    Science.gov (United States)

    Król, Małgorzata; Karoly, Agnes; Kościelniak, Paweł

    2014-09-01

    Forensic laboratories are increasingly engaged in the examination of fraudulent documents, and what is important, in many cases these are inkjet-printed documents. That is why systematic approaches to inkjet printer inks comparison and identification have been carried out by both non-destructive and destructive methods. In this study, micro-Raman spectroscopy and capillary electrophoresis (CE) were applied to the analysis of colour inkjet printer inks. Micro-Raman spectroscopy was used to study the chemical composition of colour inks in situ on a paper surface. It helps to characterize and differentiate inkjet inks, and can be used to create a spectra database of inks taken from different cartridge brands and cartridge numbers. Capillary electrophoresis in micellar electrophoretic capillary chromatography mode was applied to separate colour and colourless components of inks, enabling group identification of those components which occur in a sufficient concentration (giving intensive peaks). Finally, on the basis of the obtained results, differentiation of the analysed inks was performed. Twenty-three samples of inkjet printer inks were examined and the discriminating power (DP) values for both presented methods were established in the routine work of experts during the result interpretation step. DP was found to be 94.0% (Raman) and 95.6% (CE) when all the analysed ink samples were taken into account, and it was 96.7% (Raman) and 98.4% (CE), when only cartridges with different index numbers were considered.

  17. Immunochromatographic removal of albumin in erythropoietin biopharmaceutical formulations for its analysis by capillary electrophoresis.

    Science.gov (United States)

    Lara-Quintanar, Pilar; Lacunza, Izaskun; Sanz, Jesus; Diez-Masa, Jose Carlos; de Frutos, Mercedes

    2007-06-15

    Human serum albumin (HSA) is added to some pharmaceutical preparations as an excipient. This is the case for some of the commercial preparations of recombinant erythropoietin (rEPO). Differences in the number of the sialic acid moieties in the different rEPO glycoforms confer to these forms different net charges and different bioactivity. Knowledge of the isoforms present in each pharmaceutical product is then of interest. Differences in net charge of the rEPO forms make possible their separation by electrophoretical methods. However it has been observed in our laboratory that the amount of HSA usually present in these drug formulations interferes or even precludes separation of rEPO bands by capillary zone electrophoresis (CZE). In this work, an immunochromatographic method to remove HSA from rEPO biopharmaceutical formulations and a procedure to concentrate the sample that is needed to be performed prior to the analysis by CZE are developed. A home-made computer program to compare the percentage of correct assignments of electrophoretical bands provided by different migration parameters is used to study the effect of HSA remaining in samples on the accuracy of assignment of rEPO bands. When there exists a residual concentration of HSA in the sample (studies and for the quality control laboratories of the manufacturers. PMID:16919660

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

    NARCIS (Netherlands)

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

    1999-01-01

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

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

    Science.gov (United States)

    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

  20. Estratégias de pré-concentração em eletroforese capilar (CE: parte 1. Manipulação da velocidade eletroforética do analito Preconcentration strategies in capillary electrophoresis (CE: part 1. Manipulation of the analyte electrophoretic velocity

    Directory of Open Access Journals (Sweden)

    Maria de Lourdes Leite de Moraes

    2009-01-01

    Full Text Available Capillary electrophoresis has become a well-established and routine-based separation technique. It is based on the differences between charged analyte mobility in aqueous or organic electrolytes. Its major limitation is the sensitivity due to small sample injection volumes and the narrow diameter of the capillaries, especially when UV detection is used. There are a number of ways to increase the concentration sensitivity. This report shows some on-line preconcentration strategies to perform it in free solution capillary electrophoresis that are based on manipulation of the analyte electrophoretic velocity during the sample introduction (stacking, field amplification and transient isotachophoresis.

  1. Capacitively coupled contactless conductivity detection and sequential injection analysis in capillary electrophoresis and capillary electro-chromatography

    OpenAIRE

    Mai, Thanh Duc

    2011-01-01

    This thesis focuses on the applications of capacitively coupled contactless conductivity detection (C4D) in capillary electrophoresis (CE) hybridized with high-performance liquid chromatography (HPLC), i.e. in capillary electrochromatography and pressure-assisted capillary electrophoresis, as well as on the development and applications of an extension of CE-C4D with sequential injection analysis (SIA). At first, the in-house built C4D was used for electro-chromatographic determinations of...

  2. Capillary zone electrophoresis for analysis of phytochelatins and other thiol peptides in complex biological samples derivatized with monobromobimane.

    Science.gov (United States)

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

    2005-02-01

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

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

    Science.gov (United States)

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

    2016-08-16

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

  4. Analysis of White Blood Cell Dynamics in Nailfold Capillaries

    Science.gov (United States)

    Bourquard, Aurélien; Butterworth, Ian; Sánchez-Ferro, Alvaro; Giancardo, Luca; Soenksen, Luis; Cerrato, Carolina; Flores, Rafael; Castro-González, Carlos

    2016-01-01

    Based on video data acquired with low-cost, portable microscopy equipment, we introduce a semi-automatic method to count visual gaps in the blood flow as a proxy for white blood cells (WBC) passing through nailfold capillaries. Following minimal user interaction and a pre-processing stage, our method consists in the spatio-temporal segmentation and analysis of capillary profiles. Besides the mere count information, it also estimates the speed associated with every WBC event. The accuracy of our algorithm is validated through the analysis of two capillaries acquired from one healthy subject. Results are compared with manual counts from four human raters and confronted with related physiological data reported in literature. PMID:26738019

  5. Capillary electrophoretic enantioseparation of basic drugs using a new single-isomer cyclodextrin derivative and theoretical study of the chiral recognition mechanism.

    Science.gov (United States)

    Liu, Yongjing; Deng, Miaoduo; Yu, Jia; Jiang, Zhen; Guo, Xingjie

    2016-05-01

    A novel single-isomer cyclodextrin derivative, heptakis {2,6-di-O-[3-(1,3-dicarboxyl propylamino)-2-hydroxypropyl]}-β-cyclodextrin (glutamic acid-β-cyclodextrin) was synthesized and used as a chiral selector in capillary electrophoresis for the enantioseparation of 12 basic drugs, including terbutaline, clorprenaline, tulobuterol, clenbuterol, procaterol, carvedilol, econazole, miconazole, homatropine methyl bromide, brompheniramine, chlorpheniramine and pheniramine. The primary factors affecting separation efficiency, which include the background electrolyte pH, the concentration of glutamic acid-β-cyclodextrin and phosphate buffer concentration, were investigated. Satisfactory enantioseparations were obtained using an uncoated fused-silica capillary of 50 cm (effective length 40 cm) × 50 μm id with 120 mM phosphate buffer (pH 2.5-4.0) containing 0.5-4.5 mM glutamic acid-β-cyclodextrin as background electrolyte. A voltage of 20 kV was applied and the capillary temperature was kept at 20°C. The results proved that glutamic acid-β-cyclodextrin was an effective chiral selector for studied 12 basic drugs. Moreover, the possible chiral recognition mechanism of brompheniramine, chlorpheniramine and pheniramine on glutamic acid-β-cyclodextrin was investigated using the semi-empirical Parametric Method 3. PMID:26935589

  6. Mass spectrometric analysis of electrophoretically separated allergens and proteases in grass pollen diffusates

    Directory of Open Access Journals (Sweden)

    Geczy Carolyn L

    2003-09-01

    Full Text Available Abstract Background Pollens are important triggers for allergic asthma and seasonal rhinitis, and proteases released by major allergenic pollens can injure airway epithelial cells in vitro. Disruption of mucosal epithelial integrity by proteases released by inhaled pollens could promote allergic sensitisation. Methods Pollen diffusates from Kentucky blue grass (Poa pratensis, rye grass (Lolium perenne and Bermuda grass (Cynodon dactylon were assessed for peptidase activity using a fluorogenic substrate, as well as by gelatin zymography. Following one- or two-dimensional gel electrophoresis, Coomassie-stained individual bands/spots were excised, subjected to tryptic digestion and analysed by mass spectrometry, either MALDI reflectron TOF or microcapillary liquid chromatography MS-MS. Database searches were used to identify allergens and other plant proteins in pollen diffusates. Results All pollen diffusates tested exhibited peptidase activity. Gelatin zymography revealed high Mr proteolytic activity at ~ 95,000 in all diffusates and additional proteolytic bands in rye and Bermuda grass diffusates, which appeared to be serine proteases on the basis of inhibition studies. A proteolytic band at Mr ~ 35,000 in Bermuda grass diffusate, which corresponded to an intense band detected by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense group 1 allergen Phl p 1, was identified by mass spectrometric analysis as the group 1 allergen Cyn d 1. Two-dimensional analysis similarly demonstrated proteolytic activity corresponding to protein spots identified as Cyn d 1. Conclusion One- and two-dimensional electrophoretic separation, combined with analysis by mass spectrometry, is useful for rapid determination of the identities of pollen proteins. A component of the proteolytic activity in Bermuda grass diffusate is likely to be related to the allergen Cyn d 1.

  7. Capillary Electrophoresis Analysis of Conventional Splicing Assays

    DEFF Research Database (Denmark)

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

    2014-01-01

    Rare sequence variants in "high-risk" disease genes, often referred as unclassified variants (UVs), pose a serious challenge to genetic testing. However, UVs resulting in splicing alterations can be readily assessed by in vitro assays. Unfortunately, analytical and clinical interpretation...... of these assays is often challenging. Here, we explore this issue by conducting splicing assays in 31 BRCA2 genetic variants. All variants were assessed by RT-PCR followed by capillary electrophoresis and direct sequencing. If assays did not produce clear-cut outputs (Class-2 or Class-5 according to analytical...... International Agency for Research on Cancer guidelines), we performed qPCR and/or minigene assays. The latter were performed with a new splicing vector (pSAD) developed by authors of the present manuscript (patent #P201231427 CSIC). We have identified three clinically relevant Class-5 variants (c.682-2A>G, c...

  8. Analysis of flavonoids by capillary zone electrophoresis with electrokinetic supercharging.

    Science.gov (United States)

    Zhong, Hao; Yao, Qingqiang; Breadmore, Michael C; Li, Yumei; Lu, Yuanqi

    2011-11-01

    On-line concentration via Electrokinetic Supercharging (EKS) was used to enhance the sensitivity of the capillary electrophoretic separation of the four flavonoids naringenin, hesperetin, naringin and hesperidin. Separation conditions, including the background electrolyte pH and concentration, the length and choice of terminator and the electrokinetic injection time were optimized. The optimum conditions were: a background electrolyte of 30 mM sodium tetraborate (pH 9.5) containing 5% (v/v) of methanol, electrokinetic injection of the sample (130 s, -10 kV) followed by hydrodynamic injecting of 100 mM 2-(cyclohexylamino)ethanesulfonic acid (CHES) (17 s, 0.5 psi) as terminator, and separation with -20 kV. Under these conditions the four flavonoids could be separated with a sample-to-sample time of 15 min and detection limits from 2.0 to 6.8 ng mL(-1). When compared to a conventional hydrodynamic injection the sensitivity was enhanced between 824 and 1515 times which is 7.6-16 times higher than other CE methods for the on-line concentration of flavonoids. The applicability of the developed method was demonstrated by the detection of the four flavonoids in an aqueous extract of Clematis hexapetala pall. PMID:21949941

  9. Polyamidoamine dendrimers as sweeping agent and stationary phase for rapid and sensitive open-tubular capillary electrophoretic determination of heavy metal ions.

    Science.gov (United States)

    Ge, Ying; Guo, Yujun; Qin, Weidong

    2014-04-01

    Polyamidoamine (PAMAM) dendrimer generation 2.5 was synthesized and evaluated as sweeping agent for in-column enrichment and as stationary phase for capillary electrochromatographic separation of heavy metal ions, viz., Pb(II), Cu(II), Hg(II), Zn(II) and Co(II), in a running buffer containing 4-(2-pyridylazo)resorcinol (PAR) as a chromogenic reagent. During experiment, a plug of aqueous PAMAM generation 2.5 solution was first introduced to the capillary, followed by electrokinetic injection of the heavy metal ions under a positive voltage. In this step, PAMAM acted as a sweeping agent, stacking the metal ions on the analyte/PAMAM boundary by forming metal ion-PAMAM complexes. The second preconcentration process occurred when PAR, a stronger ligand, moving toward the injection end under the electric field, reached and re-swept the metal ion-PAMAM zone, forming metal ion-PAR complexes. During separation, the neutral PAMAM moved toward the detector with the electroosmotic flow, dynamically coating the capillary wall, forming stationary phases that affected the separation of the metal ions. Due to the function of PAMAM, the detection sensitivity and resolution of the heavy metal ions improved significantly. Under the optimum conditions, the detection limits were 0.299, 0.184, 0.774, 0.182 and 0.047 μg/L for Pb(II), Cu(II), Hg(II), Zn(II) and Co(II), respectively. The method was successfully applied to the determination of heavy metals in snow, tap and rain water samples. PMID:24607109

  10. Rapid inorganic ion analysis using quantitative microchip capillary electrophoresis

    NARCIS (Netherlands)

    Vrouwe, Elwin X.; Lüttge, Regina; Olthuis, Wouter; Berg, van den Albert

    2006-01-01

    Rapid quantitative microchip capillary electrophoresis (CE) for online monitoring of drinking water enabling inorganic ion separation in less than 15s is presented. Comparing cationic and anionic standards at different concentrations the analysis of cationic species resulted in non-linear calibratio

  11. Electrophoretic analysis, labeling and isolation of Chlamydomonas reinhardtii flagellum membrane proteins

    Directory of Open Access Journals (Sweden)

    Aleksander F. Sikorski

    2015-05-01

    Full Text Available SDS-polyacrylamide electrophoretic patterns of Chlamydomonas flagellum membrane proteins displayad 6 fractions, 3 PAS-positive among them. The surface radiolabeling of the flagellum membrane suggested an outer surface exposure of fraction '5', and internal localization of fractions '4' and '6'. Application of SDS-polyacrylamide gel electrophoresis and radiolabeled membranes allowed to isolate individual membrane polypeptides.

  12. Simultaneous electrophoretic concentration and separation of herbicides in beer prior to stacking capillary electrophoresis UV and liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

    2016-05-01

    Simultaneous electrophoretic concentration and separation (SECS) was used as a simple and environmental friendly sample preparation strategy for herbicides in beer samples. An electric field was used to facilitate the separation and concentration of the analytes based on their charge from a 20 mL sample of diluted beer into two separate 20 μL aliquots of an acceptor electrolyte housed inside a micropipette. The anionic organophosphonate and cationic quaternary ammonium herbicides were concentrated in the anodic and cathodic pipette, respectively. Under optimized conditions, SECS was completed in 30 min at an applied voltage of 150 V, which provided analyte concentration factors of up to 90. After sample preparation, the SECS concentrate of cationic and anionic herbicides was analyzed by stacking CE with UV detection and also by LC-MS, respectively. The method detection limit for the diluted and undiluted sample was as low as 3 and 15 ng/mL, respectively. The method was linear over two orders of concentration with repeatability and intermediate precision of better than 5.8 and 7.0%RSD, respectively. Accuracy values were between 91.0-115.1%. PMID:26921124

  13. The sensitive capillary electrophoretic-LIF method for simultaneous determination of curcuminoids in turmeric by enhancing fluorescence intensities of molecules upon inclusion into (2-hydroxypropyl)-β-cyclodextrin.

    Science.gov (United States)

    Kalaycıoğlu, Zeynep; Hashemi, Parya; Günaydın, Keriman; Erim, F Bedia

    2015-10-01

    Curcuminoids have received great attention in the past decades due to their health benefit properties. The aim of this study is to develop a very simple, rapid, and sensitive capillary zone electrophoresis technique coupled with a laser induced fluorescence detector (LIF) for the simultaneous determination of three major curcuminoids of turmeric, namely, curcumin, demethoxy curcumin (DMC), and bisdemethoxy curcumin (BDMC). Background electrolyte was selected as borate at pH 9.6 and (2-hydroxypropyl)-β-cyclodextrin (2-HP-β-CD) was added to prevent rapid alkali degradation of curcuminoids in buffer and to increase fluorescence intensities of molecules. With the addition of 2-HP-β-CD to the separation electrolyte, the fluorescence signal intensities of curcuminoids were enhanced considerably by 30, 40, and 54 fold for curcumin, DMC, and BDMC, respectively. The three curcuminoids of turmeric were fully separated and quantified in less than 4.5 min. The repeatability of the peak areas of curcuminoids for intra-day and inter-day experiments was in the satisfactory range of 2.26 and 2.55%, respectively. The LOD and LOQ values for the developed method were equal to or less than 0.081 and 0.270 μg/mL, respectively, for all curcuminoids. The developed method was successfully applied to find curcuminoids amount in turmeric samples and herbal supplements.

  14. Capillary Electrophoresis-based Methodology Development for Biomolecule Analysis

    OpenAIRE

    Li, Ni

    2011-01-01

    Capillary electrophoresis (CE) is a separation tool with wide applications in biomolecule analysis. Fast and high-resolution separation requiring minute sample volumes is advantageous to study multiple components in biological samples. Flexible modes and methods can be developed. In this thesis, I focus on developing and applying novel CE methods to study multi-target nucleic acid sensing with high sensitivity (Part I) and interactions between multiple components, i.e. proteins, nanoparticles...

  15. Molecular analysis and physicochemical properties of electrophoretic variants of wild soybean Glycine soja storage proteins.

    Science.gov (United States)

    Fukuda, Takako; Maruyama, Nobuyuki; Kanazawa, Akira; Abe, Jun; Shimamoto, Yoshiya; Hiemori, Miki; Tsuji, Hideaki; Tanisaka, Takatoshi; Utsumi, Shigeru

    2005-05-01

    Cultivated soybeans (Glycine max) are derived from wild soybeans (Glycine soja) and can be crossed with them to produce fertile offspring. The latter exhibit greater genetic variation than the former, suggesting a possibility that wild soybeans contain storage proteins with properties different from and better than those of cultivated soybeans. To identify a wild soybean suitable for breeding a new soybean cultivar, we analyzed seed proteins from 390 lines of wild soybeans by electrophoresis. We found some lines containing electrophoretic variants of glycinin and beta-conglycinin subunits: one line containing a small alpha' subunit of beta-conglycinin and two and five lines containing small A3 and large A4 polypeptides of glycinin, respectively. Beta-Conglycinin and glycinin containing such variant subunits exhibited solubility and emulsifying ability similar to those of the predominant types of wild and cultivated soybeans. Glycinins containing small A3 and large A4 gave a shoulder derived from the start of denaturation at a temperature 4 degrees C lower than that of glycinin from the predominant types of wild and cultivated soybeans, although their thermal denaturation midpoint temperatures were very similar to each other. Cloning and sequencing of the predominant and variant subunit cDNAs revealed that the small alpha' and the small A3 lacked 24 amino acid residues in the extension region and four amino acid residues in the hypervariable region, respectively, and that the large A4 did not have an insert corresponding to the difference in the electrophoretic mobility but Arg279 and Gln305 were replaced by glutamine and histidine, respectively, in the hypervariable region. These suggest that small differences even in the hypervariable region can affect the thermal stability, as well as the electrophoretic mobilities, of the proteins.

  16. Analysis of roller pen inks by capillary zone electrophoresis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Pengcheng; WANG Yanji; XU Yuanyuan; YAO Lijuan

    2007-01-01

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

  17. Quality criterion to optimize separations in capillary electrophoresis: Application to the analysis of harmala alkaloids.

    Science.gov (United States)

    Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G

    2016-08-19

    In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model. PMID:27443250

  18. Investigation of the free flow electrophoretic process. Volume 2: Technical analysis

    Science.gov (United States)

    Weiss, R. A.; Lanham, J. W.; Richman, D. W.; Walker, C. D.

    1979-01-01

    The effect of gravity on the free flow electrophoretic process was investigated. The demonstrated effects were then compared with predictions made by mathematical models. Results show that the carrier buffer flow was affected by gravity induced thermal convection and that the movement of the separating particle streams was affected by gravity induced buoyant forces. It was determined that if gravity induced buoyant forces were included in the mathematical models, then effective predictions of electrophoresis chamber separation performance were possible. The results of tests performed using various methods of electrophoresis using supportive media show that the mobility and the ability to separate were essentially independent of concentration, providing promise of being able to perform electrophoresis with higher inlet concentrations in space.

  19. Direct coupling of supported liquid membranes to capillary electrophoresis for analysis of complex samples: A tutorial

    OpenAIRE

    Kubáň, P. (Pavel); Boček, P. (Petr)

    2013-01-01

    This tutorial provides an overview of direct coupling of extraction techniques based on supported liquid membranes to capillary electrophoresis for treatment and subsequent analysis of complex samples.

  20. glyXalign: high-throughput migration time alignment preprocessing of electrophoretic data retrieved via multiplexed capillary gel electrophoresis with laser-induced fluorescence detection-based glycoprofiling.

    Science.gov (United States)

    Behne, Alexander; Muth, Thilo; Borowiak, Matthias; Reichl, Udo; Rapp, Erdmann

    2013-08-01

    Glycomics has become a rapidly emerging field and monitoring of protein glycosylation is needed to ensure quality and consistency during production processes of biologicals such as therapeutic antibodies or vaccines. Glycoanalysis via multiplexed CGE with LIF detection (xCGE-LIF) represents a powerful technique featuring high resolution, high sensitivity as well as high-throughput performance. However, sample data retrieved from this method exhibit challenges for downstream computational analysis due to intersample migration time shifts as well as stretching and compression of electropherograms. Here, we present glyXalign, a freely available and easy-to-use software package to automatically correct for distortions in xCGE-LIF based glycan data. We demonstrate its ability to outperform conventional algorithms such as dynamic time warping and correlation optimized warping in terms of processing time and alignment accuracy for high-resolution datasets. Built upon a set of rapid algorithms, the tool includes an intuitive graphical user interface and allows full control over all parameters. Additionally, it visualizes the alignment process and enables the user to readjust misaligned results. Software and documentation are available at http://www.glyxera.com.

  1. The 'Densitometric Image Analysis Software' and its application to determine stepwise equilibrium constants from electrophoretic mobility shift assays.

    Directory of Open Access Journals (Sweden)

    Liesbeth van Oeffelen

    Full Text Available Current software applications for densitometric analysis, such as ImageJ, QuantityOne (BioRad and the Intelligent or Advanced Quantifier (Bio Image do not allow to take the non-linearity of autoradiographic films into account during calibration. As a consequence, quantification of autoradiographs is often regarded as problematic, and phosphorimaging is the preferred alternative. However, the non-linear behaviour of autoradiographs can be described mathematically, so it can be accounted for. Therefore, the 'Densitometric Image Analysis Software' has been developed, which allows to quantify electrophoretic bands in autoradiographs, as well as in gels and phosphorimages, while providing optimized band selection support to the user. Moreover, the program can determine protein-DNA binding constants from Electrophoretic Mobility Shift Assays (EMSAs. For this purpose, the software calculates a chosen stepwise equilibrium constant for each migration lane within the EMSA, and estimates the errors due to non-uniformity of the background noise, smear caused by complex dissociation or denaturation of double-stranded DNA, and technical errors such as pipetting inaccuracies. Thereby, the program helps the user to optimize experimental parameters and to choose the best lanes for estimating an average equilibrium constant. This process can reduce the inaccuracy of equilibrium constants from the usual factor of 2 to about 20%, which is particularly useful when determining position weight matrices and cooperative binding constants to predict genomic binding sites. The MATLAB source code, platform-dependent software and installation instructions are available via the website http://micr.vub.ac.be.

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

    Science.gov (United States)

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

    2013-03-01

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

  3. Capillary Electrophoretic Technologies for Single Cell Metabolomics

    Science.gov (United States)

    Lapainis, Theodore E.

    2009-01-01

    Understanding the functioning of the brain is hindered by a lack of knowledge of the full complement of neurotransmitters and neuromodulatory compounds. Single cell measurements aid in the discovery of neurotransmitters used by small subsets of neurons that would be diluted below detection limits or masked by ubiquitous compounds when working with…

  4. Nonlinear analysis of capillary instability with heat and mass transfer

    Science.gov (United States)

    Awasthi, Mukesh Kumar; Agrawal, G. S.

    2012-06-01

    The nonlinear capillary instability of the cylindrical interface between the vapor and liquid phases of a fluid is studied when there is heat and mass transfer across the interface, using viscous potential flow theory. The fluids are considered to be viscous and incompressible with different kinematic viscosities. Both asymmetric and axisymmetric disturbances are considered. The analysis is based on the method of multiple scale perturbation and the nonlinear stability is governed by first-order nonlinear partial differential equation. The stability conditions are obtained and discussed theoretically as well as numerically. Regions of stability and instability have been shown graphically indicating the effect of various parameters. It has been observed that the heat and mass transfer has stabilizing effect on the stability of the system in the nonlinear analysis for both axisymmetric as well as asymmetric disturbances.

  5. Applications of capillary electrophoresis in DNA mutation analysis of genetic disorders.

    OpenAIRE

    Le, H; Fung, D.; Trent, R.J.

    1997-01-01

    AIM: To facilitate DNA mutation analysis by use of capillary electrophoresis. METHODS: The usefulness and applications of capillary electrophoresis in DNA fragment sizing and sequencing were evaluated. RESULTS: DNA mutation testing in disorders such as cystic fibrosis, Huntington disease, alpha thalassaemia, and hereditary fructose intolerance were undertaken effectively. However, sizing the (CAG)n repeat in the case of Huntington disease was a potential problem when using capillary electroph...

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

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, C.A.; Townsley, C.

    1995-04-01

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

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

    Science.gov (United States)

    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

  8. Capillary Electrophoretic Analysis of Common Illicit Drugs%常见毒品的毛细管电泳分析

    Institute of Scientific and Technical Information of China (English)

    孟品佳; 孙毓庆; 姜兆林; 姚丽娟; 王景翰

    1999-01-01

    系统地研究了毛细管电泳分析中各种因素对常见毒品混合物分析的影响,用均匀设计确定了适用几类毒品分离分析的最佳电泳条件. 并采用固相提取技术、毛细管区带电泳检测方法对血和尿生物检材中的冰毒、吗啡、单乙酰吗啡、可待因、海洛因等毒品进行了测定. 通过对各种提取剂回收率的测定, 认为GDX301和反相C18提取效果较好; 并考察了几种毒品的线性关系、最小检测量等, 为体内毒品分析提供了一些可借鉴的数据.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    Science.gov (United States)

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

    2008-09-26

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

  12. Capillary isotachophoresis with ESI-MS detection: Methodology for highly sensitive analysis of ibuprofen and diclofenac in waters.

    Science.gov (United States)

    Malá, Zdena; Gebauer, Petr; Boček, Petr

    2016-02-11

    The possibilities of reaching higher sensitivity in capillary electrophoretic analyses of complex samples with ESI-MS detection were investigated on the example of analysis of diclofenac and ibuprofen in waters. The applied separation approach is based on application of isotachophoresis that ensures permanent stacking of analytes until they reach the detector. Investigation of the possibilities of MS detector optimization have shown that optimization of fragmentor voltage and working in the SIM mode with collection of data for multiple fragments both increases the method specificity and approx. doubles its sensitivity. Combination with an offline SPE preconcentration step resulted in very high sensitivity of the described methodology with a reached LOD below 2 × 10(-12) M, corresponding to analyte levels of 0.6 ng L(-1) of diclofenac and 0.4 ng L(-1) of ibuprofen. The results demonstrate that CE-MS, particularly when performed in the ITP mode, has the potential to reach sensitivities comparable to HPLC-MS.

  13. Biochemical Analysis of Autophagy in Algae and Plants by Monitoring the Electrophoretic Mobility of ATG8.

    Science.gov (United States)

    Pérez-Pérez, María Esther; Andrés-Garrido, Ascensión; Crespo, José L

    2016-01-01

    Identification of specific autophagy markers has been fundamental to investigate autophagy as catabolic process. Among them, the ATG8 protein turned out to be one of the most widely used and specific molecular markers of autophagy both in higher and lower eukaryotes. Here, we describe how ATG8 can be used to monitor autophagy in Chlamydomonas and Arabidopsis by western blot analysis. PMID:27424752

  14. Recent advances in the analysis of biological particles by capillary electrophoresis

    OpenAIRE

    Kostal, Vratislav; Arriaga, Edgar A.

    2008-01-01

    This review covers research papers published in the years 2005–2007 that describe the application of capillary electrophoresis to the analysis of biological particles such as whole cells, subcellular organelles, viruses and microorganisms.

  15. Coated capillaries with highly charged polyelectrolytes and carbon nanotubes co-aggregated with sodium dodecyl sulphate for the analysis of sulfonylureas by capillary electrophoresis.

    Science.gov (United States)

    El-Debs, Racha; Nehmé, Reine; Claude, Bérengère; Motteau, Solène; Togola, Anne; Berho, Catherine; Morin, Philippe

    2014-11-01

    Sulfonylureas (SUs) are one of the most widely used herbicides to control weeds in crops. Herein, capillary electrophoresis (CE) was used to determine four sulfonylureas in natural waters, namely chlorsulfuron (CS), iodosulfuron methyl (IM), metsulfuron methyl (MSM) and mesosulfuron methyl (MSS). First of all, a bare silica capillary was chosen with 10mM of 1-butyl-3-methylimidazolium tetrafluoroborate (bminBF4) as electrophoretic buffer (pH 9.6) containing 2 mg L(-1) of surfactant-coated single-wall carbon nanotubes (SC-SWCNTs). A dramatic deviation in migration times was observed. Therefore, a poly(diallyldimethylammonium) chloride (PDADMAC) statically coated cationic capillary was used to improve repeatability and to alter the selectivity of the separation. The electroosmotic flow (EOF) measurement revealed that the SC-SWCNTs were strongly adsorbed at the surface of the PDADMAC coating even in the absence of the surfactant-coated nanotubes in the electrolyte buffer. Consequently, a stable strong cathodic EOF and excellent repeatabilities were obtained with relative standard deviations (RSDs) on migration times and on corrected peak areas below 0.9 and 1.5%, respectively. The separation of the SUs was conducted in only 6 min. No regeneration of the coating between analyses was necessary, and high peak efficiencies up to 173,000 theoretical plates were obtained. The bi-layer coating was subsequently used to analyze sulfonylureas in tap water, in several mineral waters as well as in underground waters spiked with SUs and directly injected into the CE capillary.

  16. ELECTROPHORETIC SEPARATION AND COMPARATIVE ANALYSIS OF SILK GLAND PROTEINS FROM BOMBYX AND PHILOSAMIA

    OpenAIRE

    Muzafar A Bhat, Punyavathi and Manjunatha H Boregowda*

    2014-01-01

    A comparative analysis of protein extracted from different regions of silk glands in the Bombyx mori L. and Philosamia ricini Hutt was performed employing single-dimensional-electrophoresis technique. Notably, a protein extracted directly from the lumen of the middle silk gland yielded two discrete protein bands with molecular mass of 325 and 26 kDa representing fibroin heavy (H) and low (L) chains than whole silk gland of B. mori. Contrastingly, such differentiation in protein separation cou...

  17. Structural analysis of electrophoretic variation in the genome profiles of rotavirus field isolates.

    OpenAIRE

    Clarke, I. N.; McCrae, M A

    1982-01-01

    Detailed structural studies were undertaken on five isolates of bovine rotavirus which showed variability in the migration patterns of their genome segments on electrophoresis in polyacrylamide gels. The individual genome segments of each isolate were characterized by partial digestion of terminally radiolabeled RNA with a base-specific nuclease. This analysis showed that whereas mobility variations were always associated with detectable changes in nucleotide sequence, sequence changes at lea...

  18. Electrophoretic mobility shift assays: analysis of tRNA binding to the T box riboswitch antiterminator RNA.

    Science.gov (United States)

    Anupam, R; Zhou, S; Hines, J V

    2015-01-01

    Changes in electrophoretic mobility upon complex formation with RNA can be used to probe structure-function relationships that are critical for complex formation. Here, we describe the application of this technique to monitor tRNA binding to the T box riboswitch antiterminator RNA. PMID:25352142

  19. Comparison of chiral electrophoretic separation methods for phenethylamines and application on impurity analysis.

    Science.gov (United States)

    Borst, Claudia; Holzgrabe, Ulrike

    2010-12-15

    A chiral microemulsion electrokinetic chromatography method has been developed for the separation of the enantiomers of the phenethylamines ephedrine, N-methylephedrine, norephedrine, pseudoephedrine, adrenaline (epinephrine), 2-amino-1-phenylethanol, diethylnorephedrine, and 2-(dibutylamino)-1-phenyl-1-propanol, respectively. The separations were achieved using an oil-in-water microemulsion consisting of the oil-component ethyl acetate, the surfactant sodium dodecylsulfate, the cosurfactant 1-butanol, the organic modifier propan-2-ol and 20mM phosphate buffer pH 2.5 as aqueous phase. For enantioseparation sulfated beta-cyclodextrin was added. The method was compared to an already described CZE method, which made use of heptakis(2,3-di-O-diacetyl-6-O-sulfo)-beta-cyclodextrin (HDAS) as chiral selector. Additionally, the developed method was successfully applied to the related substances analysis of noradrenaline, adrenaline, dipivefrine, ephedrine and pseudoephedrine monographed in the European Pharmacopoeia 6.

  20. Electrophoretic protein patterns and numerical analysis of Candida albicans from the oral cavities of healthy children

    Directory of Open Access Journals (Sweden)

    Boriollo Marcelo Fabiano Gomes

    2003-01-01

    restricted dissemination route of these microorganisms in some groups of healthy scholars, which may be dependent of either socioeconomic categories or geographic site of each child. In contrast to the higher similarity, the lower similarity or higher polymorphism degree (0.499 < S D < 0.788 of protein profiles was shown in 23 (30.6% C. albicans oral isolates. Considering the social epidemiological aspect, 42.1%, 41.7%, 26.6%, 23.5%, and 16.7% were isolates from children concerning to socioeconomic categories A, D, C, B, and E, respectively, and geographically, 63.6%, 50%, 33.3%, 33.3%, 30%, 25%, and 14.3% were isolates from children from schools LAE (Liceu Colégio Albert Einstein, MA (E.E.P.S.G. "Prof. Elias de Melo Ayres", CS (E.E.P.G. "Prof. Carlos Sodero", AV (Alphaville, HF (E.E.P.S.G. "Honorato Faustino, FMC (E.E.P.G. "Prof. Francisco Mariano da Costa", and MEP (E.E.P.S.G. "Prof. Manasses Ephraim Pereira, respectively. Such results suggest a higher protein polymorphism degree among some strains isolated from healthy children independent of their socioeconomic strata or geographic sites. Complementary studies, involving healthy students and their families, teachers, servants, hygiene and nutritional habits must be done in order to establish the sources of such colonization patterns in population groups of healthy children. The whole-cell protein profile obtained by SDS-PAGE associated with computer-assisted numerical analysis may provide additional criteria for the taxonomic and epidemiological studies of C. albicans.

  1. Fast separation and analysis of reduced monoclonal antibodies with capillary zone electrophoresis coupled to mass spectrometry.

    Science.gov (United States)

    Zhao, Yimeng; Sun, Liangliang; Knierman, Michael D; Dovichi, Norman J

    2016-02-01

    Capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) was used for analysis of reduced antibodies. We first developed a simple protocol to condition commercial linear-polyacrylamide coated capillaries for use in top-down proteomics. We then suspended reduced antibodies in a solution of 35% acetic acid, 50% acetonitrile in water. Heavy and light chains were baseline resolved within 10 min and with 3-30 µg/mL detection limits using a 0.1% aqueous formic acid background electrolyte. Quintuplicate runs of a two-antibody mixture produced relative standard deviations of ∼1% in migration time and 10% in peak amplitudes. Resolution was further improved for the two-antibody mixture by using 5% acetic acid as the background electrolyte, highlighting the potential of capillary electrophoresis-mass spectrometry for analysis of antibody mixtures. PMID:26653481

  2. Transient analysis of a capillary pumped loop heat pipe

    Science.gov (United States)

    Kiper, A. M.; Feric, G.; Anjum, M. I.; Swanson, T. D.

    1990-01-01

    A bench-top Capillary Pumped Loop (CPL) test system has been developed and tested to investigate the transient mode operation of this system by applying a step power input to the evaporators. Tests were conducted at several power input and evaporator inlet subcooling combinations. In addition, a lumped-heat-capacity model of the CPL test system has been presented which is used for predicting qualitatively the transient operation characteristics. Good agreement has been obtained between the predicted and the measured temperature variations. A simple evaporator inlet subcooler model has also been developed to study effects of inlet subcooling on the steady-state evaporator wall temperature. Results were compared with the test data collected.

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

    Science.gov (United States)

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

    2004-06-01

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

  4. Advances in capillary electrophoresis : In-line preconcentration for biomedical analysis. Impurity profiling of heparin

    NARCIS (Netherlands)

    van der Hoorn, Y.H.

    2015-01-01

    Capillary electrophoresis (CE) has shown to be highly suitable for the analysis of polar and ionogenic compounds in biomedical and pharmaceutical samples. Separation with CE is based on the charge-to-size ratio of analytes. The application of CE for bioanalysis may be hindered by its relatively low

  5. ZIC-HILIC monolithic capillary column coupled with MALDI-MS: A tool for glycan analysis

    OpenAIRE

    Šesták, J. (Jozef); Křenková, J. (Jana); Moravcová, D. (Dana); Planeta, J. (Josef); Kahle, V. (Vladislav)

    2014-01-01

    In this contribution, we report analysis of glycans enzymatically released from bovine ribonuclease B (RNase B) and human immunoglobulin G (hIgG) combining glycan separation using the synthesized zwitterionic silica-based monolithic capillary column and off-line MALDI-MS detection.

  6. Demonstrating Chemical and Analytical Concepts in the Undergraduate Laboratory Using Capillary Electrophoresis and Micellar Electrokinetic Chromatography

    Science.gov (United States)

    Palmer, Christopher P.

    1999-11-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

  8. Separation of ions in acidic solution by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, M.

    1997-10-08

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

  9. Bis-Indole Derivatives for Polysaccharide Compositional Analysis and Chiral Resolution of D-, L-Monosaccharides by Ligand Exchange Capillary Electrophoresis Using Borate-Cyclodextrin as a Chiral Selector

    Directory of Open Access Journals (Sweden)

    Wen-Bin Yang

    2011-02-01

    Full Text Available A series of aldo-bis-indole derivatives (aldo-BINs was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV absorbing aldo-BINs. The use of a capillary electrophoretic method to separate these novel aldo-BIN derivatives was established. The capillary electrophoresis conditions were set by using borate buffer (100 mM at high pH (pH 9.0. The limit of determination was assessed to be 25 nM. The enantioseparation of D, L-pairs of aldo-BINs based on chiral ligand-exchange capillary electrophoresis technology was also achieved by using modified hydroxypropyl-β-cyclodextrin as the chiral selector in the presence of borate buffer. This aldose labeling method was applied successfully to the compositional and configurational analysis of saccharides, exemplified by a rapid and efficient method to simultaneously analyze the composition and configuration of saccharides from the medicinal herbs Cordyceps sinensis and Dendrobium huoshanense.

  10. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    OpenAIRE

    Svetlana Hrouzková; Eva Matisová

    2012-01-01

    Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC) and fast CG...

  11. Surface modification of inorganic black particles for electrophoretic display

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Deuk; Ahn, Woo Jin; Choi, Hyoung Jin [Inha University, Incheon (Korea, Republic of)

    2014-11-15

    Inorganic black particles (Black 444) were modified with poly(methyl methacrylate) as a shell material by using dispersion polymerization to improve their dispersion stability in a medium oil for electrophoretic display applications. They were also positively charged with vinylimidazole to enhance their electrophoretic mobility. The morphology and the shape of the composite particles were characterized by using scanning electron microscopy. The thermal properties and the chemical structure of the samples were examined by using thermogravimetric analysis and Fourier transform infrared spectroscopy, respectively. In addition, the electrophoretic mobility and the zeta-potential of the black444 /PMMA /vinylimidazole particles in a dielectric fluid were measured by using optical microscopy and electrophoretic light scattering. With increasing positive charge, the black444 /PMMA /vinylimidazole particles showed improved electrophoretic characteristics compared to pristine Black 444.

  12. Application of the TVD scheme to the nonlinear instability analysis of a capillary jet

    Science.gov (United States)

    Chuech, Stephen G.; Yan, Ming-Ming

    2006-12-01

    In the past, when either the perturbation-type method or direct-simulation approach was used to analyse capillary jets, the governing equations, which are parabolic in time and elliptic in space, were simplified or linearized. In the present study, the convective derivative term and a full, nonlinear form of the capillary pressure term are retained in the governing equations to investigate nonlinear effects on the break-up of capillary jets. In this work, the TVD (i.e. total variation diminishing) scheme with flux-vector splitting is applied to obtain the solutions of the system of nonlinear equations in a matrix form. Numerical results show that the present nonlinear model predicts longer jet break-up lengths and slower growth rates for capillary jets than the previous linear model does. Comparing with other measurements from past literatures, the nonlinear results are consistent with the experimental data and appear more accurate than the linear analysis. In the past, the classic perturbation-type analyses assumed constant growth rates for the fundamental and all harmonic components. By contrast, the present model is able to capture the local features of growth rates, which are not spatially and temporally constant.

  13. Electrophoretic karyotype of Cercospora kikuchii.

    Science.gov (United States)

    Hightower, R C; Callahan, T M; Upchurch, R G

    1995-02-01

    Classical genetic analyses are not possible with the phytopathogenic fungus Cercospora kikuchii since no sexual stage has been identified. To facilitate gene mapping and to develop an understanding of the genome organization of C. kikuchii, an electrophoretic karyotype has been obtained using contour-clamped homogeneous electric field gel electrophoresis (CHEF). Eight chromosomes, two of which migrate as a doublet, have been separated into seven bands ranging from 2.0 to 5.5 Mb. Using this determination of chromosome number and size, the total genome size of C. kikuchii is estimated to be 28.4 Mb. In addition, genes encoding tubulin, ribosomal DNA, and four previously isolated light-enhanced cDNAs from C. kikuchii were assigned to chromosomes by Southern-hybridization analysis of CHEF blots.

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

    Directory of Open Access Journals (Sweden)

    Cheng-Huan Hsieh

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

  15. Analysis of Evaporation Heat Transfer of Thin Liquid Film in a Capillary of Equilateral Triangular Cross-Section

    Institute of Scientific and Technical Information of China (English)

    Miao Jianyin; Wang Jinliang; Ma Tongze

    2001-01-01

    In this paper, theoretical analysis on evaporating heat transfer in capillary with equilateral triangular cross section is presented and numerical calculations based on glass-water system are carried out. Considering evaporation mechanism in capillary with polygonal section, one-dimensional model is used to describe the three-dimensional case. The evaporating meniscus in the capillary along axis can be divided into six regions. The following conclusions are obtained: (1) The local heat transfer coefficients and heat fluxes in capillary increase quickly in the first and second regions, and slowly in the third region. The maximum value appears at interline between the third and fourth regions, then gradually decreases in the last three regions. (2) The average heat transfer coefficients decrease when the sizes of the capillary section increase, and become larger under higher wall temperature.

  16. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    International Nuclear Information System (INIS)

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

  17. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    Science.gov (United States)

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

    2015-12-01

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

  18. Analysis of proteins in biological samples by capillary sieving electrophoresis with postcolumn derivatization/laser-induced fluorescence detection.

    Science.gov (United States)

    Kaneta, Takashi; Ogura, Takehito; Imasaka, Totaro

    2011-04-01

    Previously, we have demonstrated postcolumn derivatization of proteins separated by capillary sieving electrophoresis (CSE), in which naphthalene-2,3-dicarbaldehyde was employed as a fluorogenic labeling reagent. Standard proteins separated by CSE were reacted with naphthalene-2,3-dicarbaldehyde in the presence of 2-mercaptoethanol (2-ME) which plays a role of a reducing agent in the derivatization reaction. To improve the sensitivity, we attempted the use of ethanethiol instead of 2-ME. Ethanethiol showed 1.4- to 4.5-fold lower limits of detection for proteins than 2-ME. Furthermore, we found that 8-aminopyrene-1,3,6-trisulfonate (APTS) is a good marker for relative electrophoretic mobilities of proteins in CSE. Since APTS is a fluorescent and trivalent anion, it generates strong fluorescence and migrates faster than any of the proteins. Therefore, we employed APTS as a marker to obtain the relative electrophoretic mobilities of proteins. The present method was applied to the analyses of proteins in biological samples. Human Ewing's family tumor cell line 'RDES' was used as a sample. The cultured cells were lysed with a buffer containing Tris-HCl, NaCl, sodium dodecyl sulfate, and 2-ME. After denaturation, the lysate was directly introduced into the capillary. Several peaks, which would correspond to proteins with molecular mass ranging from 10 to 93 kDa, were found in the cell lysate. In addition, we measured a milk sample by the CSE with postcolumn derivatization. The electropherogram showed five major peaks which corresponded to α-lactalbumin, β-lactoglobulin, κ-casein, bovine serum albumin, and mixture of α- and β-casein. PMID:21449073

  19. Analysis of Alkaloids from Physalis peruviana by Capillary GC, Capillary GC-MS, and GC-FTIR.

    Science.gov (United States)

    Kubwabo, C; Rollmann, B; Tilquin, B

    1993-04-01

    The alkaloid composition of the aerial parts and roots of PHYSALIS PERUVIANA was analysed by capillary GC (GC (2)), GC (2)-MS and GC (2)-FTIR. Eight alkaloids were identified, three of those alkaloids are 3beta-acetoxytropane and two N-methylpyrrolidinylhygrine isomers, which were not previously found in the genus PHYSALIS. A reproduction of the identification of alkaloids detected in the plant by the use of retention indices has been proposed. PMID:17230349

  20. Classification of electrophoretic registers from meningitis contaminated rats

    Directory of Open Access Journals (Sweden)

    Luis E Mendoza

    2015-10-01

    Full Text Available This paper proposes a new method for classification of Capillary Electrophoretic Registers (CER retrieved from cerebrospinal fluid sample taken from meningitis contaminated rats. The proposed approach applies several signal processing tools such as, wavelet analysis (WA, dynamic programming, principal component analysis (PCA and support vector machines (SVM, for data pre-processing, feature extraction and CER classification. Furthermore, an algorithm is developed that detects zones in the CER where local energy variations between study groups (meningitis group and control group are observed. This algorithm help us to identify the effects that Kliebsella Pneumonie (KP bacteria produce in certain substances (aminoacids that are part of the cerebrospinal fluid samples. It is shown that Meningitis disease can be effectively detected, analyzing the CER with the proposed methods. Futhermore, we show that exploiting the information related to the local energy variation improves the classification correctness rate up to 97.3%. This classification performance is obtained using least square SVM (LS-SVM as classification tools and the parameterized CER representation proposed in this paper.

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

    Science.gov (United States)

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

    2012-01-01

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

  2. Nano electrospray gas-phase electrophoretic mobility molecular analysis (nES GEMMA) of liposomes: applicability of the technique for nano vesicle batch control

    Science.gov (United States)

    Weiss, Victor U.; Urey, Carlos; Gondikas, Andreas; Golesne, Monika; Friedbacher, Gernot; von der Kammer, Frank; Hofmann, Thilo; Andersson, Roland; Marko-Varga, György; Marchetti-Deschmann, Martina

    2016-01-01

    Liposomes are biodegradable nanoparticle vesicles consisting of a lipid bilayer encapsulating an aqueous core. Entrapped cargo material is shielded from the extra-vesicular medium and sustained release of encapsulated material can be achieved. However, application of liposomes as nano-carriers demands their characterization concerning size and size distribution, particle-number concentration, occurrence of vesicle building blocks in solution and determination of the resulting vesicle encapsulation capacity. These questions can be targeted via gas-phase electrophoretic mobility molecular analysis (GEMMA) based on a nano electrospray (nES) charge-reduction source. This instrument separates single-charged nanoparticles in the gas-phase according to size in a high-laminar sheath-flow by means of an orthogonal, tunable electric field. nES GEMMA analysis enables to confirm liposome integrity after passage through the instrument (in combination with atomic force microscopy) as well as to exclude vesicle aggregation. Additionally, nanoparticle diameters at peak apexes and size distribution data are obtained. Differences of hydrodynamic and dry particle diameter values, as well as the effect of number- and mass-based concentration data analysis on obtained liposome diameters are shown. Furthermore, the repeatability of liposome preparation is studied, especially upon incorporation of PEGylated lipids in the bilayer. Finally, the instruments applicability to monitor mechanical stress applied to vesicles is demonstrated. PMID:27549027

  3. Contactless conductometric determination of methanol and ethanol in samples containing water after their electrophoretic desalination.

    Science.gov (United States)

    Tůma, Petr; Opekar, František

    2015-08-01

    Determination of the contents of methanol and ethanol in aqueous solutions was performed by measuring the permittivity of solutions using a contactless conductivity detector (C(4) D) normally used for detection in capillary electrophoresis. The detection cell is a section of a fused silica capillary with an internal diameter of 50 μm with a pair of conductivity electrodes on the external walls. The C(4) D response to samples of methanol/water and ethanol/water mixtures is linear in the concentration interval of approx. 40-100% v/v alcohol content. In the analysis of technical samples of methanol and ethanol, the determination is disturbed by the presence of even trace amounts of salts. This interference can be effectively eliminated by integrated electrophoretic desalination of the sample by the application of a direct current electric voltage with a magnitude of 10 kV to the capillary with the injected sample zone. Under these conditions, the ions migrate out of the sample zone and the detector response is controlled purely by the permittivity of the solvent/water zone. Desalinating is effective for NaCl contents in the range from 0 to 5 mmol/L NaCl. The effectiveness of the desalinating process has been verified on MeOH/water samples and in determination of the ethanol content in distilled beverages normally available in the retail network.

  4. Electrophoretic karyotype for Dictyostelium discoideum.

    OpenAIRE

    Cox, E. C.; Vocke, C. D.; Walter, S; Gregg, K Y; Bain, E S

    1990-01-01

    This paper reports on the separation of the Dictyostelium discoideum chromosomes by pulse-field electrophoresis and the correlation of the electrophoretic pattern with linkage groups established by classical genetic methods. In two commonly used laboratory strains, five chromosome-sized DNA molecules have been identified. Although the majority of the molecular probes used in this study can be unambiguously assigned to established linkage groups, the electrophoretic karyotype differs between t...

  5. Automated sample preparation and analysis using a sequential-injection-capillary electrophoresis (SI-CE) interface.

    Science.gov (United States)

    Kulka, Stephan; Quintás, Guillermo; Lendl, Bernhard

    2006-06-01

    A fully automated sequential-injection-capillary electrophoresis (SI-CE) system was developed using commercially available components as the syringe pump, the selection and injection valves and the high voltage power supply. The interface connecting the SI with the CE unit consisted of two T-pieces, where the capillary was inserted in one T-piece and a Pt electrode in the other (grounded) T-piece. By pressurising the whole system using a syringe pump, hydrodynamic injection was feasible. For characterisation, the system was applied to a mixture of adenosine and adenosine monophosphate at different concentrations. The calibration curve obtained gave a detection limit of 0.5 microg g(-1) (correlation coefficient of 0.997). The reproducibility of the injection was also assessed, resulting in a RSD value (5 injections) of 5.4%. The total time of analysis, from injection, conditioning and separation to cleaning the capillary again was 15 minutes. In another application, employing the full power of the automated SIA-CE system, myoglobin was mixed directly using the flow system with different concentrations of sodium dodecyl sulfate (SDS), a known denaturing agent. The different conformations obtained in this way were analysed with the CE system and a distinct shift in migration time and decreasing of the native peak of myoglobin (Mb) could be observed. The protein samples prepared were also analysed with off-line infrared spectroscopy (IR), confirming these results. PMID:16732362

  6. Available energy analysis of new tandem double-capillary tube refrigeration system for refrigerator-freezers

    Institute of Scientific and Technical Information of China (English)

    Maogang HE; Xinzhou SONG; Ying ZHANG; Jiantao ZHANG

    2008-01-01

    A new tandem double-capillary tube refri-geration system for refrigerator-freezers is proposed. A capillary tube was added between the two evaporators in the fresh and frozen food storage chests to raise the evaporation temperature of the refrigerating chamber, and reduce the heat exchange temperature difference and the available energy loss. Peng-Robinson (P-R) equation of state was adopted to calculate the thermodynamic properties of the refrigerants, and the available energy analysis of the vapor compression refrigeration cycle was programmed to calculate the thermodynamic perfor-mances of the new and the conventional refrigeration cycle of the refrigerator-freezer. The calculation results show that the available energy efficiency of the conven-tional refrigeration cycle of the refrigerator-freezer is 21.20% and 20.57%, respectively when the refrigerant is R12 and R134a, while that of the double-capillary tube refrigeration cycle of the refrigerator-freezer is 23.97% and 23.44%, respectively. By comparison, the available energy efficiency of the new refrigeration system increases by 13.07% and 13.95%, respectively.

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

    Science.gov (United States)

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

    2005-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wenwan Zhong

    2003-08-05

    Capillary electrophoresis (CE) offers many advantages over conventional analytical methods, such as speed, simplicity, high resolution, low cost, and small sample consumption, especially for the separation of enantiomers. However, chiral method developments still can be time consuming and tedious. They designed a comprehensive enantioseparation protocol employing neutral and sulfated cyclodextrins as chiral selectors for common basic, neutral, and acidic compounds with a 96-capillary array system. By using only four judiciously chosen separation buffers, successful enantioseparations were achieved for 49 out of 54 test compounds spanning a large variety of pKs and structures. Therefore, unknown compounds can be screened in this manner to identify optimal enantioselective conditions in just one rn. In addition to superior separation efficiency for small molecules, CE is also the most powerful technique for DNA separations. Using the same multiplexed capillary system with UV absorption detection, the sequence of a short DNA template can be acquired without any dye-labels. Two internal standards were utilized to adjust the migration time variations among capillaries, so that the four electropherograms for the A, T, C, G Sanger reactions can be aligned and base calling can be completed with a high level of confidence. the CE separation of DNA can be applied to study differential gene expression as well. Combined with pattern recognition techniques, small variations among electropherograms obtained by the separation of cDNA fragments produced from the total RNA samples of different human tissues can be revealed. These variations reflect the differences in total RNA expression among tissues. Thus, this Ce-based approach can serve as an alternative to the DNA array techniques in gene expression analysis.

  9. Capillary electrophoresis with direct chemiluminescence detection for the analysis of catecholamines in human urine

    Institute of Scientific and Technical Information of China (English)

    Cheng Quan Wang; Hui Wang; Yan Ming Liu

    2007-01-01

    A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis (CE) with direct chemiluminescence (CL) detection is described. The detection limits (S/N = 3) were 1.3 × 10-8 g/mL for isoprenaline,1.0 × 10-8 g/mL for epinephrine and 2.8 × 10-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.

  10. High Throughput Sample Preparation and Analysis for DNA Sequencing, PCR and Combinatorial Screening of Catalysis Based on Capillary Array Technique

    Energy Technology Data Exchange (ETDEWEB)

    Yonghua Zhang

    2002-05-27

    Sample preparation has been one of the major bottlenecks for many high throughput analyses. The purpose of this research was to develop new sample preparation and integration approach for DNA sequencing, PCR based DNA analysis and combinatorial screening of homogeneous catalysis based on multiplexed capillary electrophoresis with laser induced fluorescence or imaging UV absorption detection. The author first introduced a method to integrate the front-end tasks to DNA capillary-array sequencers. protocols for directly sequencing the plasmids from a single bacterial colony in fused-silica capillaries were developed. After the colony was picked, lysis was accomplished in situ in the plastic sample tube using either a thermocycler or heating block. Upon heating, the plasmids were released while chromsomal DNA and membrane proteins were denatured and precipitated to the bottom of the tube. After adding enzyme and Sanger reagents, the resulting solution was aspirated into the reaction capillaries by a syringe pump, and cycle sequencing was initiated. No deleterious effect upon the reaction efficiency, the on-line purification system, or the capillary electrophoresis separation was observed, even though the crude lysate was used as the template. Multiplexed on-line DNA sequencing data from 8 parallel channels allowed base calling up to 620 bp with an accuracy of 98%. The entire system can be automatically regenerated for repeated operation. For PCR based DNA analysis, they demonstrated that capillary electrophoresis with UV detection can be used for DNA analysis starting from clinical sample without purification. After PCR reaction using cheek cell, blood or HIV-1 gag DNA, the reaction mixtures was injected into the capillary either on-line or off-line by base stacking. The protocol was also applied to capillary array electrophoresis. The use of cheaper detection, and the elimination of purification of DNA sample before or after PCR reaction, will make this approach an

  11. Diamond electrophoretic microchips-Joule heating effects

    Energy Technology Data Exchange (ETDEWEB)

    Karczemska, Anna T., E-mail: anna.karczemska@p.lodz.pl [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Witkowski, Dariusz [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Ralchenko, Victor, E-mail: ralchenko@nsc.gpi.ru [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Bolshakov, Andrey; Sovyk, Dmitry [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Lysko, Jan M., E-mail: jmlysko@ite.waw.pl [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Fijalkowski, Mateusz, E-mail: petr.louda@vslib.cz [Technical University of Liberec, Faculty of Mechanical Engineering (Czech Republic); Bodzenta, Jerzy, E-mail: jerzy.bodzenta@polsl.pl [Silesian University of Technology, Institute of Physics, 2 Krzywoustego str., 44-100 Gliwice (Poland); Hassard, John, E-mail: j.hassard@imperial.ac.uk [Imperial College of Science, Technology and Medicine, London (United Kingdom)

    2011-03-15

    Microchip electrophoresis (MCE) has become a mature separation technique in the recent years. In the presented research, a polycrystalline diamond electrophoretic microchip was manufactured with a microwave plasma chemical vapour deposition (MPCVD) method. A replica technique (mould method) was used to manufacture microstructures in diamond. A numerical analysis with CoventorWare{sup TM} was used to compare thermal properties during chip electrophoresis of diamond and glass microchips of the same geometries. Temperature distributions in microchips were demonstrated. Thermal, electrical, optical, chemical and mechanical parameters of the polycrystalline diamond layers are advantageous over traditionally used materials for microfluidic devices. Especially, a very high thermal conductivity coefficient gives a possibility of very efficient dissipation of Joule heat from the diamond electrophoretic microchip. This enables manufacturing of a new generation of microdevices.

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

    Science.gov (United States)

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

    2010-11-01

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

  13. A new injection method for soil nutrient analysis in capillary electrophoresis

    Science.gov (United States)

    Smolka, M.; Puchberger-Enengl, D.; Bipoun, M.; Fercher, G.; Klasa, A.; Krutzler, C.; Keplinger, F.; Vellekoop, M. J.

    2013-05-01

    We present a new method for the direct injection of liquid sample into a capillary electrophoresis (CE) device. Instead of a double-T injection mechanism, a single inlet provided with a membrane filter is used. From a reservoir on top of this inlet, the liquid directly enters the separation channel through the membrane. The driving force is a short electrical pulse. This avoids an additional sample channel, so that the chip needs only three microfluidic connects and no mechanical sample pumping is demanded. The high injection reproducibility and the comparatively simple setup open up the way for mobile application of soil analysis.

  14. The ‘Densitometric Image Analysis Software’ and Its Application to Determine Stepwise Equilibrium Constants from Electrophoretic Mobility Shift Assays

    OpenAIRE

    Liesbeth van Oeffelen; Eveline Peeters; Phu Nguyen Le Minh; Daniël Charlier

    2014-01-01

    Current software applications for densitometric analysis, such as ImageJ, QuantityOne (BioRad) and the Intelligent or Advanced Quantifier (Bio Image) do not allow to take the non-linearity of autoradiographic films into account during calibration. As a consequence, quantification of autoradiographs is often regarded as problematic, and phosphorimaging is the preferred alternative. However, the non-linear behaviour of autoradiographs can be described mathematically, so it can be accounted for....

  15. The analysis of cations and anions in illicit heroin using capillary electrophoresis with indirect UV detection.

    Science.gov (United States)

    Lurie, I S

    1996-01-01

    Methodology is presented for the analysis of cations and anions in illicit heroin using CE with indirect UV detection. The cations investigated include ammonium, calcium, potassium, magnesium, and sodium; the anions included acetate, chloride, citrate, phosphate, sulfate, and tartrate. For cations, the Ion Phor run buffer (Dionex Corp., Sunnyvale, CA, U.S.A.) consisting of 4 mM copper sulfate, 4 mM formic acid, and 3 mM 18-crown-6 (pH 3.0) was used. For anions, proprietary reagents were used, including the Anitron run buffer (PE Applied Biosystems, Foster City, CA, U.S.A.) and Micro-Coat capillary charge-reversal agent (PE Applied Biosystems), which was utilized to flush the capillary prior to each analysis. Lithium nitrate was used as an internal standard; excellent long- and short-term precision in relative retention times were obtained for both cations and anions. The short-term precision in peak areas was satisfactory. For the various ions examined, a linearity range of a little less than two orders of magnitude was observed. The methodology is capable of analyzing ions down to the 10(-3)% level relative to heroin.

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  17. Electrophoretic analysis of different human growth hormone preparations:characterization and molecular weight estimation of isohormones and other proteic components

    International Nuclear Information System (INIS)

    Twelve human growth hormone (hGH) preparations were studied on analytical polyacrilamide gel electrophoresis with the purpose of evaluating degree of homogeneity of the extracts, the geometric mean radius (R) sup(-) and the molecular weight (MW) of the protein hormone. A standard curve was used for ten proteins of known molecular weight, where the square root of the retardation coefficient (K sub(R)) was plotted against R sup(-). Five isohormones were identified and defined as charge isomers, based on their different relative free mobility and on their similar R sup(-)(1.81-1.97 nm) and MW (20300-26000 d) values. The heterogeneity of all preparations was due to the presence in general of three isohormones. In five preparations, isohormones B, C1 and C2, were predominant. In recent hGH (IEA) preparations by the method of ROOS, the isohormones C2, D and E were identified while in an older one, isohormones E and E1 were detected. From two to five minor components were found in all samples. Moreover the same type of analysis was carried out on several fractions from protein peaks II and III eluting from Sephadex G 100 purification of three hGH (IEA) extracts. The isohormones start to appear in peak II and their relative concentration is in agreement with the peak III profile read at 280 nm. Practically all secondary components were present in peak II and in most of peak III, showing a type of heterogeneity due to hGH polymeric forms and a relatively small presence of contaminants. (Author)

  18. Analysis of Soft Drinks: UV Spectrophotometry, Liquid Chromatography, and Capillary Electrophoresis

    Science.gov (United States)

    McDevitt, Valerie L.; Rodriguez, Alejandra; Williams, Kathryn R.

    1998-05-01

    Instrumental analysis students analyze commercial soft drinks in three successive laboratory experiments. First, UV multicomponent analysis is used to determine caffeine and benzoic acid in Mello YelloTM using the spectrophotometer's software and manually by the simultaneous equations method. The following week, caffeine, benzoic acid and aspartame are determined in a variety of soft drinks by reversed-phase liquid chromatography using 45% methanol/55% aqueous phosphate, pH 3.0, as the mobile phase. In the third experiment, the same samples are analyzed by capillary electrophoresis using a pH 9.4 borate buffer. Students also determine the minimum detection limits for all three compounds by both LC and CE. The experiments demonstrate the analytical use and limitations of the three instruments. The reports and prelab quizzes also stress the importance of the chemistry of the three compounds, especially the relationships of acid/base behavior and polarity to the LC and CE separations.

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

    Directory of Open Access Journals (Sweden)

    Arın Gül Dal

    2014-01-01

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

  20. Protein analysis by membrane preconcentration-capillary electrophoresis: systematic evaluation of parameters affecting preconcentration and separation.

    Science.gov (United States)

    Rohde, E; Tomlinson, A J; Johnson, D H; Naylor, S

    1998-08-25

    Fast and efficient analysis of proteins in physiological fluids is of great interest to researchers and clinicians alike. Capillary electrophoresis (CE) has proven to be a potentially valuable tool for the separation of proteins in specimens. However, a generally acknowledged drawback of this technique is the limited sample volumes which can be loaded onto the CE capillary which results in a poor concentration limit of detection. In addition, matrix components in samples may also interfere with separation and detection of analytes. Membrane preconcentration-CE (mPC-CE) has proved to be effective in overcoming these problems. In this report, we describe the systematic evaluation of parameters affecting on-line preconcentration/clean-up and separation of protein mixtures by mPC-CE. Method development was carried out with a standard mixture of proteins (lysozyme, myoglobin, carbonic anhydrase, and human serum albumin). First, using MALDI-TOF-MS, membrane materials with cation-exchange (R-SO3H) or hydrophobic (C2, C8, C18, SDB) characteristics were evaluated for their potential to retain proteins in mPC cartridges. Hydrophobic membranes were found most suitable for this application. Next, all mPC-CE analysis of protein samples were performed in polybrene coated capillaries and parameters affecting sample loading, washing and elution, such as the composition and volume of the elution solvent were investigated. Furthermore, to achieve optimal mPC-CE performance for the separation of protein mixtures parameters affecting postelution focusing and electrophoresis, including the composition of the background electrolyte and a trailing stacking buffer were varied. Optimal conditions for mPC-CE analysis of proteins using a C2 impregnated membrane preconcentration (mPC) cartridge were achieved with a background electrolyte of 5% acetic acid and 2 mM ammonium acetate, 60 nl of 80% acetonitrile in H2O as an elution solvent, and 60 nl of 0.5% ammonium hydroxide as a trailing

  1. Correlation dimension analysis and capillary wave turbulence in Dragon-Wash phenomena

    Institute of Scientific and Technical Information of China (English)

    Peng Huai-Wu; Li Rui-Qu; Chen Song-Ze; Li Cun-Biao

    2008-01-01

    This paper describes the evolution of surface capillary waves of deep water excited by gradually increasing the lateral external force at a single frequency.The vertical velocities of the water surface are measured by using a Polytec Laser Vibrometer with a thin layer of aluminium powder scattering on the surface to reflect the laser beam.Nonlinear interaction processes result in a stationary Fourier spectrum of the vertical surface velocities (the same as the surface elevation),i.e.Iω~ω-3.5.The observed spectrum can be interpreted as a wave-turbulent Kolmogorov spectrum for the case of 'narrowband pumping' for a direct cascade of energy.Correlation dimension analysis of the whole development process reveals four distinct stages during the wave structure development and identifies the wave turbulence stage.

  2. Analysis of ecstasy tablets using capillary electrophoresis with capacitively coupled contactless conductivity detection.

    Science.gov (United States)

    Porto, Suely K S S; Nogueira, Thiago; Blanes, Lucas; Doble, Philip; Sabino, Bruno D; do Lago, Claudimir L; Angnes, Lúcio

    2014-11-01

    A method for the identification of 3,4-methylenedioxymethamphetamine (MDMA) and meta-chlorophenylpiperazine (mCPP) was developed employing capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C(4) D). Sample extraction, separation, and detection of "Ecstasy" tablets were performed in Ecstasy tablets seized in Rio de Janeiro, Brazil, were analyzed by CE-C(4) D and compared against routine gas chromatography-mass spectrometry (GC-MS). The CE method demonstrated sufficient selectivity to discriminate the two target drugs, MDMA and mCPP, from the other drugs present in seizures, namely amphepramone, fenproporex, caffeine, lidocaine, and cocaine. Separation was performed in <90 sec. The advantages of using C(4) D instead of traditional CE-UV methods for in-field analysis are also discussed.

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

    Institute of Scientific and Technical Information of China (English)

    Xiang Dong XU; Yong Gang HU; Ze Yu YANG

    2006-01-01

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

  4. Correlation dimension analysis and capillary wave turbulence in Dragon-Wash phenomena

    Science.gov (United States)

    Peng, Huai-Wu; Li, Rui-Qu; Chen, Song-Ze; Li, Cun-Biao

    2008-02-01

    This paper describes the evolution of surface capillary waves of deep water excited by gradually increasing the lateral external force at a single frequency. The vertical velocities of the water surface are measured by using a Polytec Laser Vibrometer with a thin layer of aluminium powder scattering on the surface to reflect the laser beam. Nonlinear interaction processes result in a stationary Fourier spectrum of the vertical surface velocities (the same as the surface elevation), i.e. Iω ~ ω-3.5. The observed spectrum can be interpreted as a wave-turbulent Kolmogorov spectrum for the case of 'narrowband pumping' for a direct cascade of energy. Correlation dimension analysis of the whole development process reveals four distinct stages during the wave structure development and identifies the wave turbulence stage.

  5. Functional integration of PCR amplification and capillary electrophoresis in a microfabricated DNA analysis device.

    Science.gov (United States)

    Woolley, A T; Hadley, D; Landre, P; deMello, A J; Mathies, R A; Northrup, M A

    1996-12-01

    Microfabricated silicon PCR reactors and glass capillary electrophoresis (CE) chips have been successfully coupled to form an integrated DNA analysis system. This construct combines the rapid thermal cycling capabilities of microfabricated PCR devices (10 degrees C/s heating, 2.5 degrees C/s cooling) with the high-speed (Real-time monitoring of PCR target amplification in these integrated PCR-CE devices is also feasible. Amplification of the beta-globin target as a function of cycle number was directly monitored for two different reactions starting with 4 x 10(7) and 4 x 10(5) copies of DNA template. This work establishes the feasibility of performing high-speed DNA analyses in microfabricated integrated fluidic systems. PMID:8946790

  6. Analysis of Glutamic Acid in Cerebrospinal Fluid by Capillary Electrophoresis with High Frequency Conductivity Detection

    Institute of Scientific and Technical Information of China (English)

    Hai Yun ZHAI; Jun Mei WANG; Xiao Li YAO; Xue Cai TAN; Pei Xiang CAI; Zuan Guang CHEN

    2005-01-01

    A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillary electrophoresis with high frequency conductivity detection (contactless conductivity detection) was described. The CSF sample was pretreated with silver cation resin to remove high concentration of Cl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8 mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of 5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used for analysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.

  7. Collagen Content and Electrophoretic Analysis of Type I Collagen in Breast Skin of Heterozygous Naked Neck and Normally Feathered Commercial Broilers

    OpenAIRE

    BİLGEN, Güldehen

    1999-01-01

    This study was conducted to evaluate the breast skin collagen content and electrophoretic analyses of type I collagen in heterozygous naked neck and normally feathered commercial chicks. A total of 72 birds from each genotype were randomly selected at 7 weeks and slaughtered. Breast skin was separated from each carcass and was analysed for collagen content and gel electrophopresis of type I collagen was performed. Males had significantly higher level of skin collagen content than females i...

  8. Analysis of endocrine disrupting pesticides by capillary GC with mass spectrometric detection.

    Science.gov (United States)

    Matisová, Eva; Hrouzková, Svetlana

    2012-09-01

    Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC) and fast CGC with mass spectrometric detection (MS) has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP) residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  9. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    Directory of Open Access Journals (Sweden)

    Svetlana Hrouzková

    2012-09-01

    Full Text Available Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC and fast CGC with mass spectrometric detection (MS has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  10. Analysis of polycyclic aromatic hydrocarbons. I. Determination by gas chromatography with glass and fused solica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silice capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (author). 3 figs., 17 refs

  11. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs

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

    Science.gov (United States)

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

    2016-02-01

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

  13. Electrophoretic Deposition of Hydroxyapatite Coating

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition (EPD) fromethanol. The results indicated that the addition of very small amount of HCI resulted in a decrease in the aging timeas well as the suspension concentration required to obtain a coating. In addition, the results revealed the existenceof a critical saturated voltage (Vsat), which had significant effect on the quality of deposition. The mean interfacialshear strengths of HAP coatings after sintering were found to be greater than 13 MPa.

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

    Science.gov (United States)

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

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Patrícia M. de Castro Barra

    2013-01-01

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

  16. Quality Analysis of Herbal Medicine Products Prepared from Herba Sarcandrae by Capillary Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-guang; SUN Jin-ying; ZHU De-rong; YUAN Bai-qing; YOU Tian-yan

    2008-01-01

    A capillary electrophoresis with electrochemical detection(CE-ED)method was developed for the quality analysis of herbal medicine products prepared from the sanle herb of Herba Sarcandrae:Fufang Caoshanhu tablets,Qingrexiaoyanning capsules,and Xuekang oral liquids.Under the optimal analysis conditions,the low detection limit[1.0×10-7mol/L(S/N=3)]and the wide linear range(1.0×10-7-1.0×10-4 mol/L)were obtained for quality standard compound of isofraxidin.The precisions of the peak current and the migration time(as RSDs)for the real sample analysis were 2.0%-2.6%,and 1.2%-1.8%for isofraxidin,respectively.The contents of isofraxidin detected were 15.77 μg/tablet,0.48 mg/capsule,1.2 mg/ampoule(Jiangxi),and 0.44 mg/ampoule(Dalian)for Fufang Canshanhu tablets,Qingrexiao yanning capsules,and Xuekang oral liquids from different manufacturers,respectively.Quality estimate Was conducted by comparing the contents of isofraxidin in the herbal medicine products with the demanded values of Chinese pharmacopeia.In addition,based on their own unique CE-ED profiles(namely,CE-ED electropherograrns)the Xuekang oral liquids from the different manufacturers could be easily identified.

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

    Science.gov (United States)

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

    1991-12-01

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

  18. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan); Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-06-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-{sup 2}H{sub 19}, was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-{sup 2}H{sub 19} to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-{sup 2}H{sub 19}. This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  19. Fractal Analysis of Power-Law Fluid in a Single Capillary

    Institute of Scientific and Technical Information of China (English)

    YUN Mei-Juan; YU Bo-Ming; Xu Peng; CAI Jian-Chao

    2008-01-01

    The fractal expressions for flow rate and hydraulic conductivity for power-law fluids in a single capillary are derived based on the fxactal nature of tortuous capillaries.Every parameter in the proposed expressions has clear physical meaning.The flow rate and hydraulic conductivity for power-law fluids are found to be related to the tortuosity fractal dimension and the power-law index.Tjle flow rate for power-law fluids increases with the increasing power-law index but decreases with the increasing tortuosity fractal dimension.Good agreement between the model predictions for flow in a fractal capillary and in a converging-diverging duct is obtained.The results suggest that the fractal capillary model can be used to model the power-law fluids with different rheological properties.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

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

    Science.gov (United States)

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

  2. Semi-targeted analysis of metabolites using capillary-flow ion chromatography coupled to high-resolution mass spectrometry.

    Science.gov (United States)

    Burgess, Karl; Creek, Darren; Dewsbury, Paul; Cook, Ken; Barrett, Michael P

    2011-11-30

    This work describes a novel application of capillary-flow ion chromatography mass spectrometry for metabolomic analysis, and comparison of the technique to octadecyl silica and hydrophilic interaction chromatography (HILIC)-based mass spectrometry. While liquid chromatography/mass spectrometry (LC/MS) is rapidly becoming the standard technique for metabolomic analysis, metabolomic samples are extremely heterogeneous, leading to a requirement for multiple methods of analysis and separation techniques to perform a 'global' metabolomic analysis. While C18 is suitable for hydrophobic metabolites and has been used extensively in pharmaceutical drug metabolism studies, HILIC is, in general, efficient at separating polar metabolites. Phosphorylated species and organic acids are challenging to analyse and effectively quantitate on both systems. There is therefore a requirement for an MS-compatible analytical technique that can separate negatively charged compounds, such as ion-exchange chromatography. Evaluation of capillary flow ion chromatography with electrolytic suppression was performed on a library of metabolite standards and was shown to effectively separate organic acids and sugar di- and tri-phosphates. Limits of detection for these compounds range from 0.01 to 100 pmol on-column. Application of capillary ion chromatography to a comparative analysis of energy metabolism in procyclic forms of the parasitic protozoan Trypanosoma brucei where cells were grown on glucose or proline as a carbon source was demonstrated to be more effective than HILIC for detection of the organic acids that comprise glucose central metabolism and the tricarboxylic acid (TCA) cycle.

  3. Selective Photo-Initiated Electrophoretic Separator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Optics Corporation (POC) proposes to develop a Selective Photoinitiated Electrophoretic Separator (SPIES) System to address NASA's volatile gas separation...

  4. Neutron imaging and prompt gamma activation analysis using a monolithic capillary neutron lens

    International Nuclear Information System (INIS)

    Neutron focusing lenses have been shown to enhance the measurement capabilities of prompt gamma activation analysis (PGAA) for small samples (∼100 μm in size) using a reactor-based cold neutron beam. As reported in our earlier work, a cold neutron beam emerging from a 58Ni-coated guide, cross section 50 mm x 45 mm, is compressed to a spot size of about 0.54 mm (FWHM). In the current work, we report preliminary prompt gamma measurements performed with a monolithic capillary lens that accepts a 10 mm (hexagon flat-to-flat) size beam and focuses it to a spot size of 40. The smaller focal spot size enables better spatial resolution, but also makes sample alignment more challenging. We have added a neutron imaging technique to the sample positioning procedure that takes advantage of the converging and subsequent diverging nature of the focused beam. The measurement sensitivity for a 2.6 μg Gd sample has improved by a factor of 34. In addition to rastering samples in the lateral plane, we have also explored the possibility of profiling the inhomogeneity of the sample in the direction along the beam axis. (author)

  5. Stereoselective analysis of herbicides by capillary electrophoresis using sulfobutyl ether beta-cyclodextrin as chiral selector.

    Science.gov (United States)

    Desiderio, C; Polcaro, C M; Fanali, S

    1997-02-01

    Capillary zone electrophoresis has been used for the enantiomeric separation of several herbicides. Different beta-cyclodextrin (CD) derivatives have been investigated for chiral separations and among them the negatively charged sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) proved to be effective for the stereo-selective resolutions of the investigated herbicides. The effect of CD concentration, buffer pH and organic modifier on effective mobilities, resolution and selectivity of the analytes have been studied. Addition of SBE-beta-CD (5-50 mg/mL) to the buffer at pH 9 resulted in a general increase of migration times as well as resolution. A CD concentration as low as 5 mg/mL was effective to completely resolve napropamide and ethofumesate enantiomers. Buffer solutions containing 40 mg/mL of SBE-beta-CD were chosen to study the effect of buffer pH (7, 8, and 9) on chiral separation of the herbicides. No great differences in resolution and effective mobilities have been found in the pH 7-9 range. The addition of different organic modifiers to the background electrolyte at pH 9, containing 20 mg/mL of SBE-beta-CD, showed different effects. Methanol was the most effective in improving resolution but in some cases total loss in enantiomeric separation was observed. The qualitative analysis of an enantiomerically pure herbicide (flamprop isopropyl) commercial preparation is also shown. PMID:9080130

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

    Science.gov (United States)

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

    2017-01-01

    Simple and inexpensive capillary electrophoresis with UV-detection method (CE-UV) was optimized and validated for determination of six amino acids namely (alanine, asparagine, glutamine, proline, serine and valine) for Sudanese food. Amino acids in the samples were derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-UV analysis. Labeling reaction conditions (100mM borate buffer at pH 8.5, labeling reaction time 60min, temperature 70°C and NBD-Cl concentration 40mM) were systematically investigated. The optimal conditions for the separation were 100mM borate buffer at pH 9.7 and detected at 475nm. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) (RSD%) and accuracy (recovery). Good linearity was achieved for all amino acids (r(2)>0.9981) in the concentration range of 2.5-40mg/L. The LODs in the range of 0.32-0.56mg/L were obtained. Recoveries of amino acids ranging from 85% to 108%, (n=3) were obtained. The validated method was successfully applied for the determination of amino acids for Sudanese food samples. PMID:27507479

  7. A simple and compact fluorescence detection system for capillary electrophoresis and its application to food analysis.

    Science.gov (United States)

    Zhai, Haiyun; Yuan, Kaisong; Yu, Xiao; Chen, Zuanguang; Liu, Zhenping; Su, Zihao

    2015-10-01

    A novel fluorescence detection system for CE was described and evaluated. Two miniature laser pointers were used as the excitation source. A Y-style optical fiber was used to transmit the excitation light and a four-branch optical fiber was used to collect the fluorescence. The optical fiber and optical filter were imported into a photomultiplier tube without any extra fixing device. A simplified PDMS detection cell was designed with guide channels through which the optical fibers were easily aligned to the detection window of separation capillary. According to different requirements, laser pointers and different filters were selected by simple switching and replacement. The fluorescence from four different directions was collected at the same detecting point. Thus, the sensitivity was enhanced without peak broadening. The fluorescence detection system was simple, compact, low-cost, and highly sensitive, with its functionality demonstrated by the separation and determination of red dyes and fluorescent whitening agents. The detection limit of rhodamine 6G was 7.7 nM (S/N = 3). The system was further applied to determine illegal food dyes. The CE system is potentially eligible for food safety analysis. PMID:26109527

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

    Science.gov (United States)

    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

  9. Further development and applications of capillary electrophoresis with capacitively coupled contactless conductivity detection and sequential injection analysis in analytical chemistry

    OpenAIRE

    Stojkovic, Marko

    2013-01-01

    This dissertation is based on the further development and applications of capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C4D), i. e. sequential injection analysis (SIA) applications when coupled with CE-C4D, or determination and quantification of various ions that are not or barely UV absorbed. A purpose made CE-C4D system was used for determination of the DNA fragments of different length, using additives to modify the medium and to sieve ch...

  10. Ionic liquids in chromatographic and electrophoretic techniques: toward additional improvements in the separation of natural compounds

    Science.gov (United States)

    Freire, Carmen S. R.; Coutinho, João A. P.; Silvestre, Armando J. D.; Freire, Mara G.

    2016-01-01

    Due to their unique properties, in recent years, ionic liquids (ILs) have been largely investigated in the field of analytical chemistry. Particularly during the last sixteen years, they have been successfully applied in the chromatographic and electrophoretic analysis of value-added compounds extracted from biomass. Considering the growing interest in the use of ILs in this field, this critical review provides a comprehensive overview on the improvements achieved using ILs as constituents of mobile or stationary phases in analytical techniques, namely in capillary electrophoresis and its different modes, in high performance liquid chromatography, and in gas chromatography, for the separation and analysis of natural compounds. The impact of the IL chemical structure and the influence of secondary parameters, such as the IL concentration, temperature, pH, voltage and analysis time (when applied), are also critically addressed regarding the achieved separation improvements. Major conclusions on the role of ILs in the separation mechanisms and the performance of these techniques in terms of efficiency, resolution and selectivity are provided. Based on a critical analysis of all published results, some target-oriented ILs are suggested. Finally, current drawbacks and future challenges in the field are highlighted. In particular, the design and use of more benign and effective ILs as well as the development of integrated (and thus more sustainable) extraction–separation processes using IL aqueous solutions are suggested within a green chemistry perspective. PMID:27667965

  11. Capillary saturation and desaturation.

    Science.gov (United States)

    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. PMID:26764820

  12. Measuring the concentrations of drinking water disinfection by-products using capillary membrane sampling-flow injection analysis.

    Science.gov (United States)

    Geme, Gija; Brown, Michael A; Simone, Paul; Emmert, Gary L

    2005-10-01

    A capillary membrane sampling-flow injection analysis method is presented for selectively measuring the concentrations of total trihalomethanes (THMs) and total haloacetic acids (HAAs) in drinking water. The method is based on the reaction between nicotinamide and THM or HAA species to yield a fluorescent product. Two configurations are presented, one selective for total THMs and another selective for total HAAs. The construction of a capillary membrane sampler is described, and the results of method detection limit, accuracy and precision studies are reported for each method. Interference, selectivity and linearity studies are reported as well as the effect of temperature and ionic strength changes. Drinking water samples were analyzed by each proposed method and the results were compared to USEPA methods 502.2 and 552.3.

  13. Nucleation theory - Is replacement free energy needed?. [error analysis of capillary approximation

    Science.gov (United States)

    Doremus, R. H.

    1982-01-01

    It has been suggested that the classical theory of nucleation of liquid from its vapor as developed by Volmer and Weber (1926) needs modification with a factor referred to as the replacement free energy and that the capillary approximation underlying the classical theory is in error. Here, the classical nucleation equation is derived from fluctuation theory, Gibb's result for the reversible work to form a critical nucleus, and the rate of collision of gas molecules with a surface. The capillary approximation is not used in the derivation. The chemical potential of small drops is then considered, and it is shown that the capillary approximation can be derived from thermodynamic equations. The results show that no corrections to Volmer's equation are needed.

  14. Affinity chromatography and capillary electrophoresis for analysis of the yeast ribosomal proteins

    Directory of Open Access Journals (Sweden)

    Miriam S. Goyder

    2012-04-01

    Full Text Available We present a top down separation platform for yeast ribosomalproteins using affinity chromatography and capillary electrophoresiswhich is designed to allow deposition of proteins ontoa substrate. FLAG tagged ribosomes were affinity purified, andrRNA acid precipitation was performed on the ribosomes followedby capillary electrophoresis to separate the ribosomalproteins. Over 26 peaks were detected with excellent reproducibility(<0.5% RSD migration time. This is the first reportedseparation of eukaryotic ribosomal proteins using capillaryelectrophoresis. The two stages in this workflow, affinity chromatographyand capillary electrophoresis, share the advantagesthat they are fast, flexible and have small sample requirementsin comparison to more commonly used techniques. This methodis a remarkably quick route from cell to separation that hasthe potential to be coupled to high throughput readout platformsfor studies of the ribosomal proteome. [BMB reports2012; 45(4: 233-238

  15. Measurement of Liquid Viscosities in Tapered or Parabolic Capillaries.

    Science.gov (United States)

    Ershov; Zorin; Starov

    1999-08-01

    The possibility of using tapered or parabolic capillaries for measurement of liquid viscosities is investigated both experimentally and theoretically. It is demonstrated that even small deviations in capillary radius from a constant value may substantially affect measurement results. Equations are derived which allow correct analysis of the measurement results in tapered or parabolic capillaries. The following cases are analyzed: a water imbibition into a tapered or parabolic capillary and displacement of one liquid by another immiscible liquid in tapered or parabolic capillaries. Two possibilities are considered: (a) the narrow end of the capillary as capillary inlet and (b) the wide end of the capillary as capillary inlet. Copyright 1999 Academic Press.

  16. Screening of Small-Molecule Inhibitors of Protein-Protein Interaction with Capillary Electrophoresis Frontal Analysis.

    Science.gov (United States)

    Xu, Mei; Liu, Chao; Zhou, Mi; Li, Qing; Wang, Renxiao; Kang, Jingwu

    2016-08-16

    A simple and effective method for identifying inhibitors of protein-protein interactions (PPIs) was developed by using capillary electrophoresis frontal analysis (CE-FA). Antiapoptotic B-cell-2 (Bcl-2) family member Bcl-XL protein, a 5-carboxyfluorescein labeled peptide truncated from the BH3 domain of Bid (F-Bid) as the ligand, and a known Bcl-XL-Bid interaction inhibitor ABT-263 were employed as an experimental model for the proof of concept. In CE-FA, the free ligand is separated from the protein and protein-ligand complex to permit the measurement of the equilibrium concentration of the ligand, hence the dissociation constant of the protein-ligand complex. In the presence of inhibitors, formation of the protein-ligand complex is hindered, thereby the inhibition can be easily identified by the raised plateau height of the ligand and the decayed plateau of the complex. Further, we proposed an equation used to convert the IC50 value into the inhibition constant Ki value, which is more useful than the former for comparison. In addition, the sample pooling strategy was employed to improve the screening throughput more than 10 times. A small chemical library composed of synthetic compounds and natural extracts were screened with the method, two natural products, namely, demethylzeylasteral and celastrol, were identified as new inhibitors to block the Bcl-XL-Bid interaction. Cell-based assay was performed to validate the activity of the identified compounds. The result demonstrated that CE-FA represents a straightforward and robust technique for screening of PPI inhibitors. PMID:27425825

  17. A theoretical analysis to estimate the hydraulic properties of a loam soil from a capillary-evaporation process

    Science.gov (United States)

    Peña-Sancho, Carolina; Ghezzehei, Teamrat A.; Latorre, Borja; Moret-Fernández, David

    2015-04-01

    The determination of the water retention curve (WRC) parameters and the hydraulic conductivity (K) is of paramount importance in many scientific fields such as hydrology or environmental science. Their direct characterization, however, is typically cumbersome and time consuming. This work analyze the viability to estimate the α and n Van Genuchten (VG) WRC parameters and K from following processes: a capillary wetting process at saturation, an evaporation process and a capillary wetting at saturation followed by an evaporation process. The theoretical analysis was carried out on a 5 cm high and 5 cm diameter cylinder filled with loam soil using numerically generated data with the HYDRUS 2D code. The error maps for the above mentioned processes and the n-K, α-n and K-α planes were generated from the RMSE calculated between the original and the simulated cumulative curves. The deviation (%) between the optimal and original hydraulic parameters was also calculated. Results showed that the capillary plus evaporation method applied on the n-K and α-n planes was the unique process that allowed a unique and well defined minimum. For this last case, the deviation for the α and n parameter were 6'67 and 0'88%, respectively. Taking into account that K can be easy measured from the same soil cylinder by means of Darcy's law, we conclude the capillary + evaporation process can be a simple and effective alternative to estimate the WRC parameters. To this end, the hysteresis phenomena due to the wetting-evaporation process should be taking into account.

  18. TAR柱前络合、毛细管电泳分析痕量金属离子%CAPILLARY ELECTROPHORESIS FOR THE ANALYSIS OF TRACE METAL IONS USING PRE-COLUMN COMPLEXING WITH 4-(2-THIAZOLYLAZO)RESORCINOL

    Institute of Scientific and Technical Information of China (English)

    王敏; 屈锋; 林金明

    2003-01-01

    The capillary electrophoretic separation of Fe2+, Co2+, Zn2+ and Ni2+ in a phosphate buffer solution by complexing with 4-(2-thiazolylazo)resorcinol was investigated. The influences of some crucial parameters that included chelating ligand in the electrophoretic running buffer and sample solution, pH value and concentration of buffer were examined. Under optimum conditions (10mmol*l-1 NaH2PO4-Na2HPO4 buffer containing 1×10-4mol*l-1TAR, pH 7.5), a baseline separation of these metals was accomplished within 3 min. The detection limits (S/N=3) ranged from 0.013-0.14 μg*ml-1. The method was applied to analyze trace metal ions in the environmental samples.

  19. Ultrasensitive analysis of glucose in serum by capillary electrophoresis with LIF detection in combination with signal amplification strategies and on-column enzymatic assay.

    Science.gov (United States)

    Guan, Yueqing; Zhou, Guobin

    2016-03-01

    A highly specific and sensitive method for glucose quantification in human serum samples based on on-column enzymatic assay is described. In this method, the head of the capillary was used as a nanoliter-microreactor, the diluted samples spiked with a novel fluorogenic reagent named 2-[6-(4'-amino) phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (APF), and the mixed enzyme solutions of glucose oxidase (GOx) and horseradish peroxidase (HRP), were individually injected into the capillary. Hydrogen peroxide (H2 O2 ) generated in situ by catalytic reaction between GOx and glucose, activates APF in the presence of HRP to form a highly fluorescent product, which was electrophoretically separated from the unreacted APF and detected by the LIF detector. The proposed method allowed the determination of glucose down to 10 nM in real samples, with RSD values lower than 3.5%, which also has the potential for measurements of multicomponents in many other systems including measurement of α-glucosidase activity and screening for its inhibitors. PMID:26668076

  20. High Sensitivity Method to Estimate Distribution of Hyaluronan Molecular Sizes in Small Biological Samples Using Gas-Phase Electrophoretic Mobility Molecular Analysis

    Directory of Open Access Journals (Sweden)

    Lan Do

    2015-01-01

    Full Text Available Hyaluronan is a negatively charged polydisperse polysaccharide where both its size and tissue concentration play an important role in many physiological and pathological processes. The various functions of hyaluronan depend on its molecular size. Up to now, it has been difficult to study the role of hyaluronan in diseases with pathological changes in the extracellular matrix where availability is low or tissue samples are small. Difficulty to obtain large enough biopsies from human diseased tissue or tissue from animal models has also restricted the study of hyaluronan. In this paper, we demonstrate that gas-phase electrophoretic molecular mobility analyzer (GEMMA can be used to estimate the distribution of hyaluronan molecular sizes in biological samples with a limited amount of hyaluronan. The low detection level of the GEMMA method allows for estimation of hyaluronan molecular sizes from different parts of small organs. Hence, the GEMMA method opens opportunity to attain a profile over the distribution of hyaluronan molecular sizes and estimate changes caused by disease or experimental conditions that has not been possible to obtain before.

  1. In situ observation and analysis of ultrasonic capillary effect in molten aluminium.

    Science.gov (United States)

    Tzanakis, I; Xu, W W; Eskin, D G; Lee, P D; Kotsovinos, N

    2015-11-01

    An in situ synchrotron radiographic study of a molten Al-10 wt% Cu alloy under the influence of an external ultrasonic field was carried out using the Diamond-Manchester Branchline pink X-ray imaging at the Diamond Light Source in UK. A bespoke test rig was used, consisting of an acoustic transducer with a titanium sonotrode coupled with a PID-controlled resistance furnace. An ultrasonic frequency of 30 kHz, with a peak to peak amplitude at 140 microns, was used, producing a pressure output of 16.9 MPa at the radiation surface of the 1-mm diameter sonotrode. This allowed quantification of not only the cavitation bubble formation and collapse, but there was also evidence of the previously hypothesised ultrasonic capillary effect (UCE), providing the first direct observations of this phenomenon in a molten metallic alloy. This was achieved by quantifying the re-filling of a pre-existing groove in the shape of a tube (which acted as a micro-capillary channel) formed by the oxide envelope of the liquid sample. Analytical solutions of the flow suggest that the filling process, which took place in very small timescales, was related to micro-jetting from the collapsing cavitation bubbles. In addition, a secondary mechanism of liquid penetration through the groove, which is related with the density distribution of the oxides inside the groove, and practically to the filtration of aluminium melt from oxides, was revealed. The observation of the almost instantaneous re-filling of a micro-capillary channel with the metallic melt supports the hypothesised sono-capillary effect in technologically important liquids other than water, like metallic alloys with substantially higher surface tension and density. PMID:26186822

  2. Numerical analysis of capillary compensated micropolar fluid lubricated hole-entry journal bearings

    OpenAIRE

    Nathi Ram

    2016-01-01

    The micropolar lubricated symmetric/asymmetric hole-entry bearings using capillary restrictor have been analyzed in the present work. Reynolds equation for micropolar lubricant has been derived and solved by FEM. The results have been computed using selected parameters of micropolar lubricant for hole-entry hydrostatic/hybrid journal bearings. A significant increase in damping and stiffness coefficients is observed for bearings having micropolar parameter N2=0.9, lm=10 than similar bearings ...

  3. Electrophoretic Analysis on the Enzyme Hydrolysis of Chickpea Protein%鹰嘴豆分离蛋白酶解过程的电泳分析

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In this paper,we determined the degree of hydrolysis(DH) of the chickpea protein with three proteolytic enzymes of alcalase,papain and bromelain(domestic)at different times,and analysed the electrophoretic pattern of the hydrolytic products. The result shows that after treated with the proteases for three hours,the chickpea proteins were mostly hydrolysed into oligopeptides,and the DH value(35.42%)of chickpea protein hydrolyzing by the three proteases above-mentioned under each optimum conditions respectively in order was much higher than that of the DH of chickpea protein hydrolyzing by the three proteases simultaneously.%  对国产碱性蛋白酶降解鹰嘴豆分离蛋白的酶解过程及酶解产物的水解度和电泳结果进行了分析研究.结果表明,国产蛋白酶可有效降解鹰嘴豆分离蛋白为小分子蛋白肽;使用碱性蛋白酶、木瓜蛋白酶、菠萝蛋白酶顺序酶解鹰嘴豆分离蛋白3 h 时的水解度可达到35.42%以上,此时绝大多数鹰嘴豆分离蛋白被降解为小分子肽.实验结果为鹰嘴豆蛋白的开发利用与鹰嘴豆的精深加工提供了科学依据.

  4. Analysis of Capillary Tube Sludge in Refrigeration Circuit with HFC 134 a

    Science.gov (United States)

    Nakayama, Yoshinori; Yamamoto, Thutomu; Takahashi, Yuuichi; Shimizu, Yasuhiko; Takizawa, Kikuo; Yamasita, Tsugito

    We conducted a continuous test with a refrigeration test circuit using HFC 134 a,and we made a study of the form and components of the sludge inside the capillary tube comparing different kinds of lubricant from this perspective. A rotary compressor was used for the test, and HAB oil, blended oil and ester oil were employed as the lubricants. The results showed that the capillary sludge consists mainly of a copper oxide which is caused by corrosion in the case of the HAB oil, and mainly a metal soap, a decomposition product and polymeric product of the lubricant, and zeolite in the case of the ester oil. In order to decrease the amount of these sludges, it is necessary, in the former case, to remove the remaining chlorine solvents and other impurities in the constituent parts of the refrigeration test circuit and, in the latter case, to develop a stabler lubricant and zeolite. In the case of the blended oil, we discovered that zeolite and ohter substances are deposited in the capillary tube over the course of time.

  5. Development of chiral methodologies by capillary electrophoresis with ultraviolet and mass spectrometry detection for duloxetine analysis in pharmaceutical formulations.

    Science.gov (United States)

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

    2014-10-10

    Two chiral methodologies were developed by capillary electrophoresis (CE) with UV and mass spectrometry (MS) detection to ensure the quality control of the drug duloxetine, commercialized as a pure enantiomer. Both methods were optimized to achieve a high baseline enantioresolution (Rs>2) and an acceptable precision (RSD values developed methods were validated and applied for the first time to the analysis of four pharmaceutical formulations. The content of R-duloxetine in all these samples was below the detection limit and the amount of S-duloxetine was in good agreement with the labeled content, obtaining results by the two methods that did not differ significantly (p-values >0.05).

  6. Derivatization in Capillary Electrophoresis.

    Science.gov (United States)

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS). PMID:27645730

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

    Directory of Open Access Journals (Sweden)

    Elena Domínguez Vega

    2014-12-01

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

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

    Science.gov (United States)

    Domínguez Vega, Elena; Marina, Maria Luisa

    2014-01-01

    Advances in biotechnology have increased the demand for suitable analytical techniques for the analysis of genetically modified organisms. Study of the substantial equivalence, discrimination between transgenic and non-transgenic cultivars, study of the unintended effects caused by a genetic modification or their response to diverse situations or stress conditions (e.g., environmental, climatic, infections) are some of the concerns that need to be addressed. Capillary electrophoresis (CE) is emerging as an alternative to conventional techniques for the study and characterization of genetically modified organisms. This article reviews the most recent applications of CE for the analysis and characterization of transgenic cultivars in the last five years. Different strategies have been described depending on the level analyzed (DNA, proteins or metabolites). Capillary gel electrophoresis (CGE) has shown to be particularly useful for the analysis of DNA fragments amplified by PCR. Metabolites and proteins have been mainly separated using capillary zone electrophoresis (CZE) using UV and MS detection. Electrophoretic chips have also proven their ability in the analysis of transgenic cultivars and a section describing the new applications is also included. PMID:25535077

  9. Lanthanides separation by counter - current electrophoretic using α - hydroxyisobutyric acid

    International Nuclear Information System (INIS)

    Studies about counter-current electrophoretic separation of rare earth metal ions using α-hydroxyisobutyric acid as complexing electrolyte are discussed. La, Pr, Nd, Sm and Eu were separated and fractions with purities better than 99,9% were obtained, using neutron activation analysis. A relation between the first stability constant of the α-hydroxyisobutyrate/lanthanide complexes and their migration velocities were observed. (M.J.C.)

  10. Determination of zeta-potential, charge, and number of organic ligands on the surface of water soluble quantum dots by capillary electrophoresis

    OpenAIRE

    Voráčová, I. (Ivona); Klepárník, K. (Karel); Lišková, M. (Marcela); Foret, F

    2015-01-01

    The number of charges and/or organic ligands covalently attached to the surface of CdTe quantum dot nanoparticles has been determined from their electrophoretic mobilities measured in capillaries filled with free electrolyte buffers. Three sizes of water soluble CdTe quantum dots with 3-mercaptopropionic and thioglycolic acids as surface ligands were prepared. Their electrophoretic mobilities in different pH and ionic strength values of separation buffers were measured by capillary elect...

  11. Validation of STR typing by capillary electrophoresis.

    Science.gov (United States)

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

    2001-05-01

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

  12. Polyaniline coated micro-capillaries for continuous flow analysis of aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Florea, Larisa; Diamond, Dermot [CLARITY: Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin (Ireland); Benito-Lopez, Fernando, E-mail: fernando.lopez@dcu.ie [CLARITY: Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin (Ireland); CIC MicroGUNE, Microtechnologies Cooperative Research Center, Arrasate-Mondragon (Spain)

    2013-01-08

    Highlights: Black-Right-Pointing-Pointer Microcapillaries were coated with polyaniline nanofibres by the grafting approach. Black-Right-Pointing-Pointer Optical detection of aqueous ammonia in continuous flow mode was achieved. Black-Right-Pointing-Pointer The sensing platform can be easily regenerated after detection. Black-Right-Pointing-Pointer Very small volumes of analytes are necessary for detection. Black-Right-Pointing-Pointer The nanostructure of the coating guarantees fast response and regeneration times. - Abstract: The inner walls of fused silica micro-capillaries were successfully coated with polyaniline nanofibres using the 'grafting' approach. The optical response of polyaniline coatings was evaluated during the subsequent redoping-dedoping processes with hydrochloric acid and ammonia solutions, respectively, that were passed inside the micro-capillary in continuous flow. The optical absorbance of the polyaniline coatings was measured and analysed in the wavelength interval of [300-850 nm] to determine its optical sensitivity to different concentrations of ammonia. It was found that the optical properties of polyaniline coatings change in response to ammonia solutions in a wide concentration range from 0.2 ppm to 2000 ppm. The polyaniline coatings employed as a sensing material for the optical detection of aqueous ammonia have a fast response time and a fast regeneration time of less than 5 s at room temperature. The coating was fully characterised by scanning electron microscopy, Raman spectroscopy, absorbance measurements and kinetic studies. The response of the coatings showed very good reproducibility, demonstrating that this platform can be used for the development of micro-capillary integrated sensors based on the inherited sensing properties of polyaniline.

  13. Capillary absorption spectrometer and process for isotopic analysis of small samples

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

    2016-03-29

    A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

  14. Evaluation of CP sil 8 film thickness for the capillary GC analysis of methyl mercury

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Drabæk, Iver

    1992-01-01

    Different commercially available CP-Sil 8 CB capillary columns have been tested with a mixed standard containing methyl mercury chloride, ethyl mercury chloride and a stable nonpolar chlorinated hydrocarbon. The aim of the study was to see whether the columns tested could be used without special...... available insert for on-column injections on wide bore columns, and a 5.35 mum thick stationary phase. It was concluded that this CP Sil 8 CB column gave good results although minor interactions between the organo-mercury compounds and the column could be seen....

  15. Numerical analysis of capillary compensated micropolar fluid lubricated hole-entry journal bearings

    Directory of Open Access Journals (Sweden)

    Nathi Ram

    2016-06-01

    Full Text Available The micropolar lubricated symmetric/asymmetric hole-entry bearings using capillary restrictor have been analyzed in the present work. Reynolds equation for micropolar lubricant has been derived and solved by FEM. The results have been computed using selected parameters of micropolar lubricant for hole-entry hydrostatic/hybrid journal bearings. A significant increase in damping and stiffness coefficients is observed for bearings having micropolar parameter N2=0.9, lm=10 than similar bearings under Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant.

  16. Capillary electrophoresis with inhibited electrochemiluminescent detection for the trace analysis of epinephrine and dopamine

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,a novel electrochemiluminescent (ECL) detection approach was developed for highly sensitive detection of ECL inhibitors based on the ECL inhibition of Ru(bpy)32+/2-(Dibutylamino)ethanol (DBAE) system. A microfluidic ECL detection cell was fabricated to couple with the capillary electrophoresis system,the electrochemical system and the postcolumn injection system. Both Ru(bpy)32+ and DBAE solutions were injected directly to the working electrode surface by a micro-infusion system to obtain a hi...

  17. 用于高效液相色谱和开管毛细管电色谱的氢化硅胶分离材料%Hydride-Based Separation Materials for High Performance Liquid Chromatography and Open Tubular Capillary Electrochromatography

    Institute of Scientific and Technical Information of China (English)

    PESEK Joseph J; MATYSKA Maria T

    2005-01-01

    Silica hydride is a recent development in chromatographic support materials for high performance liquid chromatography (HPLC) where hydride groups replace 95% of the silanols on the surface. This conversion changes many of the fundamental properties of the material as well as the bonded stationary phases that are the result of further chemical modification of the hydride surface. Some unique chromatographic properties of hydride-based phases are described as well as some general application areas where these bonded materials may be used in preference to or have advantages not available from typical stationary phases. The fabrication, properties and applications of etched chemically modified capillaries for electrophoretic analysis are also reviewed. It is shown that the etching process creates a surface that is fundamentally different than a bare fused silica capillary. The new surface matrix produces unique electroosmotic flow properties and is more compatible with basic and biological compounds. After chemical modification of the surface, the bonded organic moiety (stationary phase) contributes to the control of migration of solutes in the capillary. Both electrophoretic and chromatographic processes take place in the etched chemically modified capillaries leading to a variety of experimental variables that can be used to optimize separations. A number of examples of separations on these capillaries are described.

  18. Soft X-Ray Emission Analysis Of A Pulsed Capillary Discharge Operated In Nitrogen

    Science.gov (United States)

    Valdivia, M. P.; Valenzuela, J. C.; Wyndham, E. S.; Favre, M.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present results from a pulsed capillary ns discharge source, operated in Nitrogen and N/He mixtures, in an alumina capillary 2.1mm long with outer diameter of 6.3mm and inner diameter of 1.6mm. The electrical energy stored is 0.5J with peak current of 6kA. Fast charging from an IGBT based pulsed power circuit allows operation at 35-600 Hz with voltages in the range of 18-24kV. Characteristic time-integrated N/He spectra were recorded and analyzed for values of 20-200 Å, with clear evidence of He-like Nitrogen emission at 28.8Å, which represents a possible source for water window soft x-ray microscopy. Filtered diode measurements reveal the influence of axial electron beams, generated by hollow cathode dynamics, on the x-ray emission in the range of 300-450 eV. We discuss optimal voltage applied and pressure conditions for soft x-ray generation. Time-integrated MCP images of a filtered slit-wire system delivered clear evidence of full wall detachment with ~500μm in radial size for the entire emission range and ~200μm for the emission in the 300-450 eV range.

  19. High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Gang Xue

    2001-12-31

    The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations (RSD) after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. The authors further improved the fluorescence detection by step laser scanning. A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluorescein is 3 x 10{sup -11} M (S/N = 3) for 5-mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  20. The inclusion complex of rosmarinic acid into beta-cyclodextrin: A thermodynamic and structural analysis by NMR and capillary electrophoresis.

    Science.gov (United States)

    Aksamija, Amra; Polidori, Ange; Plasson, Raphaël; Dangles, Olivier; Tomao, Valérie

    2016-10-01

    This work focuses on the characterization of the rosmarinic acid (RA)-β-cyclodextrin (CD) complex in aqueous solution by (1)H NMR (1D- and 2D-ROESY), completed with studies by capillary electrophoresis (CE). From the (1)H NMR data, the stoichiometry of the complex was determined by a Job's plot and the binding constant was estimated from a linear regression (Scott's method). At pH 2.9, the results showed that RA binds CD with a 1:1 stoichiometry and a binding constant Kb of 445 (±53) M(-1) or 465 (±81) M(-1) depending on the CD protons (H-5 or H-3) selected for the evaluation. The Kb value was also calculated from the CD-induced chemical shifts of each RA proton in order to collect information on the structure of the complex. The pH dependence of Kb revealed that the RA carboxylic form displays the highest affinity for CD. An investigation by capillary electrophoresis fully confirmed these results. 2D ROESY analysis provided detailed structural information on the complex and showed a strong correlation between H-3 and H-5 of CD and most RA protons. In conclusion, RA, an efficient phenolic antioxidant from rosemary with a marketing authorization, spontaneously forms a relatively stable inclusion complex with CD in water. PMID:27132848

  1. Capillary-Seeding Crystallization and Preliminary Crystallographic Analysis of a Solvent-Tolerant Elastase from Pseudomonas aeruginosa Strain K

    Directory of Open Access Journals (Sweden)

    Abu Bakar Salleh

    2013-08-01

    Full Text Available Seeding is a versatile method for optimizing crystal growth. Coupling this technique with capillary counter diffusion crystallization enhances the size and diffraction quality of the crystals. In this article, crystals for organic solvent-tolerant recombinant elastase strain K were successfully produced through microseeding with capillary counter-diffusion crystallization. This technique improved the nucleation success rate with a low protein concentration (3.00 mg/mL. The crystal was grown in 1 M ammonium phosphate monobasic and 0.1 M sodium citrate tribasic dihydrate pH 5.6. The optimized crystal size was 1 × 0.1 × 0.05 mm3. Elastase strain K successfully diffracted up to 1.39 Å at SPring-8, Japan, using synchrotron radiation for preliminary data diffraction analysis. The space group was determined to be monoclinic space group P1211 with unit cell parameters of a = 38.99 Ǻ, b = 90.173 Å and c = 40.60 Å.

  2. Electrophoretic mobilities of erythrocytes in various buffers

    Science.gov (United States)

    Plank, L. D.; Kunze, M. E.; Todd, P. W.

    1985-01-01

    The calibration of space flight equipment depends on a source of standard test particles, this test particle of choice is the fixed erythrocyte. Erythrocytes from different species have different electrophoretic mobilities. Electrophoretic mobility depends upon zeta potential, which, in turn depends upon ionic strength. Zeta potential decreases with increasing ionic strength, so cells have high electrophoretic mobility in space electrophoresis buffers than in typical physiological buffers. The electrophoretic mobilities of fixed human, rat, and rabbit erythrocytes in 0.145 M salt and buffers of varying ionic strength, temperature, and composition, to assess the effects of some of the unique combinations used in space buffers were characterized. Several effects were assessed: glycerol or DMSO (dimethylsulfoxide) were considered for use as cryoprotectants. The effect of these substances on erythrocyte electrophoretic mobility was examined. The choice of buffer depended upon cell mobility. Primary experiments with kidney cells established the choice of buffer and cryoprotectant. A nonstandard temperature of EPM in the suitable buffer was determined. A loss of ionic strength control occurs in the course of preparing columns for flight, the effects of small increases in ionic strength over the expected low values need to be evaluated.

  3. Simultaneous chromatographic fingerprinting and quantitative analysis of flavonoids in Pollen Typhae by high-performance capillary electrophoresis

    Directory of Open Access Journals (Sweden)

    Le Han

    2012-12-01

    Full Text Available To evaluate the quality of Pollen Typhae as used in traditional Chinese medicine, a high-performance capillary electrophoresis (HPCE method has been developed, validated and applied to chromatographic fingerprinting and quantitation of its eight main bioactive flavonoids (naringenin, isorhamnetin 3-O-(2G-α-l-rhamnosyl-rutinoside, rhamnetin 3-O-neohesperidoside, isorhamnetin, quercetin 3-O-(2G-α-l-rhamnosyl-rutinoside, quercetin 3-O-neohesperidoside, kaempferol and quercetin. Fingerprinting was based on the selection of nine characteristic chromatographic peaks. In quantitative analysis, the recovery of all eight compounds was in the range 98.5–102.2% with good linearity (r2>0.9919 over a relatively wide concentration range. The assay was successfully applied to the analysis of the eight bioactive flavonoids in 14 different samples. The results indicate that the assay is reproducible and precise and can be used for convenient quality assessment of Pollen Typhae.

  4. Simultaneous analysis of acidulants and preservatives in food samples by using capillary zone electrophoresis with indirect UV detection.

    Science.gov (United States)

    Yoshikawa, Kenji; Saito, Shintaro; Sakuragawa, Akio

    2011-08-01

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

  5. Analysis of pulsating heat pipe with capillary wick and varying channel diameter

    Energy Technology Data Exchange (ETDEWEB)

    Holley, B.; Amir Faghri [University of Connecticut, Storrs, CT (United States). Dept. of Mechanical University

    2005-06-01

    Variation in channel diameter is investigated as a means of enhancing heat transfer in a pulsating heat pipe with capillary wick using the model presented here. The model is one-dimensional with slug flow where the momentum equation is solved for each liquid slug. The number and mass of liquid slugs are allowed to vary throughout a simulation. The energy equation is solved both in the wall and wick and in the working fluid. The effects of diameter profile, gravity, fill ratio, and heating and cooling schemes can be studied with the model. Results yield similar trends to what has been experimentally observed. Results also indicate that heat transfer can be enhanced when the diameter of the channel is varied along the channel length, thereby providing increased range of heat load capability, less sensitivity to gravity, and in some cases smaller temperature differentials. (author)

  6. Restricted-access media development for direct analysis of drugs in biofluids using capillary liquid chromatography.

    Science.gov (United States)

    Jarmalaviciene, Reda; Kornysova, Olga; Bendokas, Vidmantas; Westerlund, Douglas; Buszewski, Boguslaw; Maruska, Audrius

    2008-07-01

    In analytical sciences the design of novel materials and stationary phases for the sample preparation and separation of analytes from biological fluids is needed. In this work we present different strategies for modification of stationary phases to produce tailored solutions for the analytical problem. In this context a novel shielded polymeric reversed-phase monolithic material was prepared in the presence of different numbers of reactive groups and concentrations of the coating polymer. Chromatographic experiments were performed using benzoic acid propyl ester in order to characterize the hydrophobicity and efficiency of the different restricted-access continuous beds prepared. Inverse size-exclusion chromatography was used for investigation of the pore structure properties of the beds. Capillary columns were applied for nanochromatography of biological fluids containing a mixture of nitrazepamum and medazepamum. PMID:18392755

  7. Cytogenetic analysis of mechanism of formation of radiation-induced chromosome exchanges. [Crepis capillaris, x radiation

    Energy Technology Data Exchange (ETDEWEB)

    Azatyan, R.A.; Akif' ev, A.P.; Shavel' zon, R.A.; Voskanyan, A.Z.; Zakaryan, M.S.

    1977-01-01

    An unusual spectrum of aberrations, characterized by a sharp exchange deficiency, was demonstrated in germinating seeds of Crepis capillaris L. synchronized with 2'-deoxy-5-fluorouridine at the start of the S phase following exposure to 100 R x-rays. The modification of the cytogenetic effect of x-radiation of dry crepis seeds (10 and 15 kR) by 5-aminouracil consisted of a higher yield of aberrations without decrease in share of exchanges of the chromosome type. The obtained data are consistent with the hypothesis that exchange aberrations occur due to interaction between spontaneous single-stranded DNA defects limited to identical or similar repeated nucleotide sequences The exchange interactions are blocked when the cells move into the stage of DNA synthesis.

  8. Capillary electrophoresis with electrochemiluminescence detection for the analysis of quinolone drugs and pharmacokinetics study

    Institute of Scientific and Technical Information of China (English)

    Yan Ming Liu; Jun Tao Cao; Hui Wang

    2008-01-01

    A novel method for the determination of two quinolone drugs norfloxacin (NOR) and levofloxacin (LVX) was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship (r ≥ 0.9991) between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection (LOD, S/N = 3) in standard solution are 4.8 × 10-7 mol/L for NOR and 6.4 × 10-7 mol/L for LVX, respectively. The limits of quantitation (LOQ, S/N = 10) in real human urine samples are 1.2 × 10-6 mol/L for NOR and 1.4 × 10-6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the study of pharmacokinetics of NOR.

  9. Analysis of Trinitrophenylated Adenosine and Inosine by Capillary Electrophoresis and γ-Cyclodextrin-Enhanced Fluorescence Detection.

    Science.gov (United States)

    Stephen, Terilyn K L; Guillemette, Katherine L; Green, Thomas K

    2016-08-01

    Monitoring molecules such as adenosine (Ado) and inosine (Ino) in the central nervous system has enabled the field of neuroscience to correlate molecular concentrations dynamics to neurological function, behavior, and disease. In vivo sampling techniques are commonly used to monitor these dynamics; however, many techniques are limited by the sensitivity and sample volume requirements of currently available detection methods. Here, we present a novel capillary electrophoresis-laser-induced fluorescence detection (CE-LIF) method that analyzes Ado and Ino by derivatization with 2,4,6-trinitrobenzenesulfonic acid to form fluorescent trinitrophenylated complexes of Ado (TNP-Ado) and Ino (TNP-Ino). These complexes exhibit ∼25-fold fluorescence enhancement upon the formation of inclusion complexes with γ-cyclodextrin (γ-CD). Association constants were determined as 4600 M(-1) for Ado and 1000 M(-1) for Ino by CE-LIF. The structure of the TNP-Ado:γ-CD complex was determined by 2D nuclear magnetic resonance (NMR) spectroscopy. Optimal trinitrophenylation reaction conditions and CE-LIF parameters were determined and resulted in the limit of detection of 1.6 μM for Ado and 4 μM for Ino. Ado and Ino were simultaneously quantified in homogenized rat forebrain samples to illustrate application of the technique. Simulated biological samples, desalted by ultrafiltration in the presence γ-CD, were concentrated on-capillary by large-volume sample stacking (LVSS) to achieve detection limits of 32 and 38 nM for TNP-Ado and TNP-Ino, respectively. PMID:27314490

  10. Electrophoretic karyotypes of some related Mucor species.

    Science.gov (United States)

    Nagy, A; Palagyi, Z; Vastag, M; Ferenczy, L; Vágvölgyi, C

    2000-07-01

    Contour clamped homogeneous electric field (CHEF) gel electrophoresis was used to obtain electrophoretic karyotypes from nine Mucor strains representing five different species (M. bainieri, M. circinelloides, M. mucedo, M. plumbeus and M. racemosus). The chromosomal banding patterns revealed high variability among the isolates. The sizes of the DNA in the Mucor chromosomes were estimated to be between 2.5 and 8.7 Mb. The total genome sizes were calculated to be between 30.0 and 44.7 Mb. The applicability of these electrophoretic karyotypes for the investigation of genome structure, for strain identification and for species delimitation is considered.

  11. Genotyping of Bacillus anthracis strains based on automated capillary 25-loci Multiple Locus Variable-Number Tandem Repeats Analysis

    Directory of Open Access Journals (Sweden)

    Ciervo Alessandra

    2006-04-01

    Full Text Available Abstract Background The genome of Bacillus anthracis, the etiological agent of anthrax, is highly monomorphic which makes differentiation between strains difficult. A Multiple Locus Variable-number tandem repeats (VNTR Analysis (MLVA assay based on 20 markers was previously described. It has considerable discrimination power, reproducibility, and low cost, especially since the markers proposed can be typed by agarose-gel electrophoresis. However in an emergency situation, faster genotyping and access to representative databases is necessary. Results Genotyping of B. anthracis reference strains and isolates from France and Italy was done using a 25 loci MLVA assay combining 21 previously described loci and 4 new ones. DNA was amplified in 4 multiplex PCR reactions and the length of the resulting 25 amplicons was estimated by automated capillary electrophoresis. The results were reproducible and the data were consistent with other gel based methods once differences in mobility patterns were taken into account. Some alleles previously unresolved by agarose gel electrophoresis could be resolved by capillary electrophoresis, thus further increasing the assay resolution. One particular locus, Bams30, is the result of a recombination between a 27 bp tandem repeat and a 9 bp tandem repeat. The analysis of the array illustrates the evolution process of tandem repeats. Conclusion In a crisis situation of suspected bioterrorism, standardization, speed and accuracy, together with the availability of reference typing data are important issues, as illustrated by the 2001 anthrax letters event. In this report we describe an upgrade of the previously published MLVA method for genotyping of B. anthracis and apply the method to the typing of French and Italian B. anthracis strain collections. The increased number of markers studied compared to reports using only 8 loci greatly improves the discrimination power of the technique. An Italian strain belonging to the

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

    Science.gov (United States)

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

    2004-04-15

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

  13. Isolation of individual fatty acids in sediments using preparative capillary gas chromatography (PCGC) for radiocarbon analysis at NIES-TERRA

    International Nuclear Information System (INIS)

    Compound-specific radiocarbon analysis (CSRA) of individual fatty acids (140-1190 μg C) in an estuarine sediment sample collected from Tokyo Bay was carried out using a recently developed preparative capillary gas chromatography (PCGC) system and accelerator mass spectrometry (AMS). The results showed that the estimated 14C ages of four components greatly varied from modern age (combined iso and anteiso C15:0, C16:0) to 17 000 years BP (C22:0), while a bulk-phase 14C age of organic matter is 5000 years BP. The 14C ages of the fatty acids derived from phytoplankton and bacteria are much younger than that of the bulk phase. On the other hand, the fatty acid originated from terrestrial higher plants (C22:0) shows an older 14C age of 17 000 years BP

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

    Science.gov (United States)

    Peng, Xuejun; Sternberg, Ethan; Dolphin, David

    2002-01-01

    A method for the separation of benzoporphyrin derivative mono- and diacid (BPDMA, BPDDA) enantiomers by laser induced fluorescence-capillary electrophoresis (LIF-CE) has been developed. By using 300 mM borate buffer, pH 9.2, 25 mM sodium cholate and 10% acetronitrile as electrolyte, +10 kV electrokinetic sampling injection of 2 s and an applied +20 kV voltage across the ends of a 37 cm capillary (30 cm to the detector, 50 microm ID), all six BPD stereoisomers were baseline-separated within 20 min. Formation constants, free electrophoretic and complexation mobilities with borate and cholate were determined based on dynamic complexation capillary electrophoresis theory. The BPD enantiomers can be quantitatively determined in the range of 10(-2)-10(-5) mg mL(-1). The correlation coefficients (r2) of the least-squares linear regression analysis of the BPD enantiomers are in the range of 0.9914-0.9997. Their limits of detection are 2.18-3.5 x 10(-3) mg mL(-1). The relative standard deviations for the separation were 2.90-4.64% (n = 10). In comparison with high-performance liquid chromatography (HPLC), CE has better resolution and efficiency. This separation method was successfully applied to the BPD enantiomers obtained from a matrix of bovine serum and from liposomally formulated material as well as from studies with rat, dog and human microsomes. PMID:11824627

  15. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    Science.gov (United States)

    Ghosal, Sandip

    2006-01-01

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

  16. SPECIES IDENTIFICATION OF MEAT BY ELECTROPHORETIC METHODS

    Directory of Open Access Journals (Sweden)

    Edward Pospiech

    2007-03-01

    Full Text Available Electrophoretic methods can be used to identify meat of various animal species. The protein electrophoresis, especially the IEF of the sarcoplasmic proteins, is a well-established technique for species identification of raw fish and is used in the control of seafood authenticity. However, in the case of the analysis of heat-processed fish, the method is applicable only to those species which possess characteristic patterns of the heat-stable parvalbumins. Heat-denatured fish muscle proteins may be solubilised by urea or sodium dodecylsulfate (SDS and separated by urea-IEF or SDS-PAGE, respectively. The comparison of these two methods allowed to conclude that, basically, each of them can be used for species identification of heated fishery products. However, extensively washed products may be preferentially analysed by the SDS-PAGE, because most of the parvalbumins are washed out leaving mainly myosins. On the other hand, the IEF method may be preferred for the differentiation of closely related species rich in parvalbumins isoforms. It is evident from the literature data that species-specific protein separations yield proteins of low molecular weight made up of three light chains of myosin (14-23 kDa, troponin (19-30 kDa and parvalbumin (about 12 kDa. Investigations showed that the SDS-PAGE method can be used to identify meats of: cattle, sheep, lambs, goats, red deer and rabbits. The technique allowed researchers to identify the following myofibrillar and sarcoplasmic muscle proteins: myosin and actin, α-actinin, tropomyosin, troponin. SDS-PAGE allowed the identification of myofibrillar proteins taking into account their molecular weights which was not possible with the assistance of the PAGIF because too many protein bands were obtained. It was possible to obtain differences in the separation of proteins characteristic for certain species, e.g. beef, resulting from the presence of sin-gle myofibrillar proteins.

  17. Precision improvement for the analysis of flavonoids in selected Thai plants by capillary zone electrophoresis.

    Science.gov (United States)

    Suntornsuk, Leena; Anurukvorakun, Oraphan

    2005-02-01

    A capillary zone electrophoresis (CZE) method for the analyses of kaempferol in Centella asiatica and Rosa hybrids and rutin in Chromolaena odorata was developed. The optimization was performed on analyses of flavonoids (e.g., rutin, kaempferol, quercetin, myricetin, and apigenin) and organic carboxylic acids (e.g., ethacrynic acid and xanthene-9-carboxylic acid) by investigation of the effects of types and amounts of organic modifiers, background electrolyte concentrations, temperature, and voltage. Baseline separation (R(s) = 2.83) of the compounds was achieved within 10 min in 20 mM NaH2PO4 - Na2HPO4 (pH 8.0) containing 10% v/v ACN and 6% v/v MeOH using a voltage of 25 kV, a temperature of 30 degrees C, and a detection wavelength set at 220 nm. The application of the corrected migration time (t(c)), using ethacrynic acid as the single marker, was efficient to improve the precision of flavonoid identification (% relative standard deviation (RSD) = 0.65%). The method linearity was excellent (r2 > 0.999) over 50-150 microg/mL. Precision (%RSD 96% and %RSDs odorata was 0.088 g/100 g (%RSD = 0.06%). PMID:15690438

  18. Analysis of Trace Ingredients in Green Tea by Capillary Electrophoresis with Amperometric Detection

    Institute of Scientific and Technical Information of China (English)

    LI Ping; DONG Shu-Qing; WANG Qing-Jiang; FANG Yu-Zhi

    2008-01-01

    In this paper, four trace ingredients (rutin, gallic acid, quercetin, chlorogenic acid) in green tea were simultaneously determined by capillary electrophoresis coupled with amperometric detection (CE-AD). Effects of several important factors such as the pH and concentration of running buffer, separation voltage, injection time and detection potential were investigated to acquire the optimum conditions. Under the optimum conditions, the analytes could be separated within 20 min at a separation voltage of 18 kV in a 60 mmol/L borate buffer (pH 8.7). A 300 μmdiameter carbon disk electrode generated good responses at 950 mV (vs. SCE) for all analytes. The relationship between the peak currents and concentrations of the analytes was linear over about three orders of magnitude with demonstrated long-term stability and reproducibility with relative standard deviations less than 3% for both migration time and peak current (n=7), which could be successfully used for the determination of the analytes in green tea with satisfactory assay results.

  19. Capillary-gravity waves on a liquid film of arbitrary depth: analysis of the wave resistance.

    Science.gov (United States)

    Wędołowski, Karol; Napiórkowski, Marek

    2013-10-01

    We discuss the wave resistance in the case of an externally perturbed viscous liquid film of arbitrary thickness. Emphasis is placed on the dependence of the wave resistance on the film thickness H, the length scale b characterizing the external perturbation, and its velocity V. In particular, the effectiveness of the mechanisms of capillary-gravity waves and the viscous dissipation localized in the vicinity of the perturbation are compared and discussed as functions of H and V. We show that, in general, the wave resistance is a nonmonotonous function of H with a maximum whose amplitude and position depend on b and V. In the case of small H the wave resistance depends on a parameter S proportional V/H(3). We find three different regimes of this parameter in which the wave resistance behaves like S(r) with the exponent r equal to 1, 1/3, and -1. These results are also obtained independently within the thin liquid film approximation. This allows us to assess the range of validity of the thin liquid film approximation in various cases, in particular its dependence on the perturbation length scale b. PMID:24229283

  20. Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Ganzera, Markus; Egger, Christoph; Zidorn, Christian; Stuppner, Hermann

    2008-05-01

    Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution containing 50 mM borax, 25 mM sodium dodecyl sulfate and 30% of acetonitrile the separation of seven flavonoids and four caffeic acid derivatives was feasible in less than 20 min. The optimized system was validated for repeatability (sigma(rel) or = 0.9996), and then successfully applied to assay several plant samples. In all of them the most dominant flavonoid was found to be quercetin 3-O-glucuronic acid, whereas 3,5-dicaffeoylquinic acid was the major phenolic acid; the total content of flavonoids and phenolic acids varied in the samples from 0.60 to 1.70%, and 1.03 to 2.24%, respectively.

  1. Development of a simplified microfluidic injector for analysis of droplet content via capillary electrophoresis.

    Science.gov (United States)

    DeLaMarre, Michael F; Shippy, Scott A

    2014-10-21

    Droplet-based microfluidic platforms sequester nanoliter to picoliter samples in an immiscible carrier phase and have gained notoriety for their ability to be used in laboratory procedures on a miniaturized scale. Recently, droplet microfluidics has been used to prevent zone diffusion in time-resolved sample collection methods and in separation techniques. The assay of droplets remains challenging, however, because the carrier phase is often incompatible with separation techniques. In this work, we report the development of a droplet injector for capillary electrophoresis (CE) which delivers 750 pL droplets to a channel for separation while excluding the fluorous carrier phase. This design is simple compared to previous reports, consisting of only two straight channels and no additional working parts such as membranes or valves. To demonstrate a proof-of-concept and characterize performance, riboflavin was used as a biologically relevant model molecule. Droplets containing a step change in riboflavin concentration were injected and mobilized by CE. The current method is capable of riboflavin peak % relative standard deviations (RSDs) down to 4.4% and temporal resolutions down to 15 s. Human urine samples containing riboflavin and its photolysis products were successfully separated and found to be chemically compatible with the injector. Our simplified design could improve robustness and ruggedness and may allow device construction via nontraditional fabrication techniques. PMID:25226066

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

    Institute of Scientific and Technical Information of China (English)

    王清江; 丁飞; 李辉; 何品刚; 方禹之

    2003-01-01

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

  3. Microchip capillary electrophoresis instrumentation for in situ analysis in the search for extraterrestrial life.

    Science.gov (United States)

    Mora, Maria F; Stockton, Amanda M; Willis, Peter A

    2012-09-01

    The search for signs of life on extraterrestrial planetary bodies is among NASA's top priorities in Solar System exploration. The associated pursuit of organics and biomolecules as evidence of past or present life demands in situ investigations of planetary bodies for which sample return missions are neither practical nor affordable. These in situ studies require instrumentation capable of sensitive chemical analyses of complex mixtures including a broad range of organic molecules. Instrumentation must also be capable of autonomous operation aboard a robotically controlled vehicle that collects data and transmits it back to Earth. Microchip capillary electrophoresis (μCE) coupled to laser-induced fluorescence (LIF) detection provides this required sensitivity and targets a wide range of relevant organics while offering low mass, volume, and power requirements. Thus, this technology would be ideally suited for in situ studies of astrobiology targets, such as Mars, Europa, Enceladus, and Titan. In this review, we introduce the characteristics of these planetary bodies that make them compelling destinations for extraterrestrial astrobiological studies, and the principal groups of organics of interest associated with each. And although the technology we describe here was first developed specifically for proposed studies of Mars, by summarizing its evolution over the past decade, we demonstrate how μCE-LIF instrumentation has become an ideal candidate for missions of exploration to all of these nearby worlds in our Solar System. PMID:22965706

  4. A Theoretical Analysis of the Influence of Electroosmosis on the Effective Ionic Mobility in Capillary Zone Electrophoresis

    Science.gov (United States)

    Hijnen, Hens

    2009-01-01

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

  5. Selective enzymatic cleavage and labeling for sensitive capillary electrophoresis laser-induced fluorescence analysis of oxidized DNA bases.

    Science.gov (United States)

    Li, Cuiping; Wang, Hailin

    2015-08-01

    Oxidatively generated DNA damage is considered to be a significant contributing factor to cancer, aging, and age-related human diseases. It is important to detect oxidatively generated DNA damage to understand and clinically diagnosis diseases caused by oxidative damage. In this study, using selective enzymatic cleavage and quantum dot (QD) labeling, we developed a novel capillary electrophoresis-laser induced fluorescence method for the sensitive detection of oxidized DNA bases. First, oxidized DNA bases are recognized and removed by one DNA base excision repair glycosylase, leaving apurinic and apyrimidinic sites (AP sites) at the oxidized positions. The AP sites are further excised by the AP nicking activity of the chosen glycosylase, generating a nucleotide gap with 5'- and 3'- phosphate groups. After dephosphorylation with one alkaline phosphatase, a biotinylated ddNTP is introduced into the nucleotide space within the DNA strand by DNA polymerase I. The biotin-tagged DNA is further labeled with a QD-streptavidin conjugate via non-covalent interactions. The DNA-bound QD is well-separated from excess DNA-unbound QD by highly efficient capillary electrophoresis and is sensitively detected by online coupled laser-induced fluorescence analysis. Using this method, we can assess the trace levels of oxidized DNA bases induced by the Fenton reaction and UV irradiation. Interestingly, the use of the formamidopyrimidine glycosylase (FPG) protein and endonuclease VIII enables the detection of oxidized purine and pyrimidine bases, respectively. Using the synthesized standard DNA, the approach has low limits of detection of 1.1×10(-19)mol in mass and 2.9pM in concentration. PMID:26105778

  6. Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

    2008-06-30

    Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

  7. Two-dimensional electrophoretic analysis of transformation-sensitive polypeptides during chemically, spontaneously, and oncogene-induced transformation of rat liver epithelial cells

    DEFF Research Database (Denmark)

    Wirth, P J; Luo, L D; Fujimoto, Y;

    1992-01-01

    Recently, we described the establishment of a computerized database of rat liver epithelial (RLE) cellular polypeptides (Wirth et al., Electrophoresis, 1991, 12, 931-954). This database has now been expanded to include the analysis of cellular polypeptide alterations during chemically (aflatoxin B1...

  8. Analysis of phenolic compounds in extra virgin olive oil by using reversed-phase capillary electrochromatography.

    Science.gov (United States)

    Aturki, Zeineb; Fanali, Salvatore; D'Orazio, Giovanni; Rocco, Anna; Rosati, Chiara

    2008-04-01

    In this work, the simultaneous separation of ten phenolic compounds (protocatechuic, p-coumaric, o-coumaric, vanillic, ferulic, caffeic, syringic acids, hydroxytyrosol, tyrosol and oleuropein) in extra virgin olive oils (EVOOs) by isocratic RP CEC is proposed. A CEC method was optimized in order to completely resolve all the analyzed compounds by studying several experimental parameters. The influence of the stationary phase type (C(18) and C(8) modified silica gel), buffer concentration and pH as well as the organic modifier content of the mobile phase on retention factors, selectivity and efficiency were evaluated in details. A capillary column packed with Cogent bidentate C(18) particles for 23 cm and a mobile phase composed by 100 mM ammonium formate buffer pH 3/H(2)O/ACN (5:65:30 v/v/v) allowed the baseline resolution of the compounds under study in less than 35 min setting the applied voltage and temperature at 22 kV and 20 degrees C, respectively. A study, evaluating the intra- and interday precision as well as LOD and LOQ and method linearity was developed in accordance with the analytical procedures for method validation. LODs were in the range of 0.015-2.5 microg/mL, while calibration curves showed a good linearity (r(2) >0.997). The CEC method was applied to the separation and determination of these compounds in EVOO samples after a suitable liquid-liquid extraction procedure. The mean recovery values of the studied compounds ranged between 87 and 99%. PMID:18383030

  9. Analysis of the interfacial properties of fibrillated and nonfibrillated oral streptococcal strains from electrophoretic mobility and titration measurements: evidence for the shortcomings of the 'classical soft-particle approach'.

    Science.gov (United States)

    Duval, Jérôme F L; Busscher, Henk J; van de Belt-Gritter, Betsy; van der Mei, Henny C; Norde, Willem

    2005-11-22

    Chemical and structural intricacies of bacterial cells complicate the quantitative evaluation of the physicochemical properties pertaining to the cell surface. The presence of various types of cell surface appendages has a large impact on those properties and therefore on various interfacial phenomena, such as aggregation and adhesion. In this paper, an advanced analysis of the electrophoretic mobilities of fibrillated and nonfibrillated strains (Streptococcus salivarius HB and Streptococcus salivarius HB-C12, respectively) is performed over a wide range of pH and ionic strength conditions on the basis of a recent electrokinetic theory for soft particles. The latter extends the approximate formalism originally developed by Ohshima by solving rigorously the fundamental electrokinetic equations without restrictions on the bacterial size, charge, and double layer thickness. It further allows (i) a straightforward implementation of the dissociation characteristics, as evaluated from titration experiments, of the ionogenic charged groups distributed throughout the bacterial cell wall and/or the surrounding exopolymer layer and (ii) the inclusion of possible specific interactions between the charged groups and ions from the background electrolyte other than charge-determining ions. The theory also enables an estimation of possible swelling/shrinking processes operating on the outer polymeric layer of the bacterium. Application of the electrokinetic model to HB and HB-C12 clearly shows a significant discrepancy between the amount of surface charges probed by electrophoresis and by protolytic titration. This is ascribed to the specific adsorption of cations onto pristine charged sites in the cell wall. Physicochemical parameters pertaining to the hydrodynamics (softness degree) and electrostatics of the bacterial cell wall (HB-C12) and soft polymeric layer (HB) are quantitatively derived.

  10. due to Capillary Forces

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2009-01-01

    Full Text Available We present modeling and analysis for the static behavior and collapse instabilities of doubly-clamped and cantilever microbeams subjected to capillary forces. These forces can be as a result of a volume of liquid trapped underneath the microbeam during the rinsing and drying process in fabrication. The model considers the microbeam as a continuous medium, the capillary force as a nonlinear function of displacement, and accounts for the mid-plane stretching and geometric nonlinearities. The capillary force is assumed to be distributed over a specific length underneath the microbeam. The Galerkin procedure is used to derive a reduced-order model consisting of a set of nonlinear algebraic and differential equations that describe the microbeams static and dynamic behaviors. We study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so-called pinned configuration. We calculate the pull-in length that distinguishes the free from the pinned configurations as a function of the beam thickness and gap width for both microbeams. Comparisons are made with analytical results reported in the literature based on the Ritz method for linear and nonlinear beam models. The instability problem, which brings the microbeam from a pinned to adhered configuration is also investigated. For this case, we use a shooting technique to solve the boundary-value problem governing the deflection of the microbeams. The critical microbeam length for this second instability is also calculated.

  11. Electrochemical Enzyme Immunoassay of Tumor Marker CA15-3 with Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Tumor marker CA15-3 was determined by using capillary electrophoretic enzyme immunoassay with electrochemical detection (CE-EIA-ED). The method can be used to detect CA15-3 with a limit of 0.024 U/mL.

  12. Isotope dilution analysis for urinary fentanyl and its main metabolite, norfentanyl, in patients by isotopic fractionation using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan). Faculty of Pharmacy and Pharmaceutical Sciences; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-07-01

    Isotope dilution analysis was applied to determine urinary excretion of fentanyl (FT) and its main metabolite, norfentanyl (Nor-FT), by isotopic fractionation using a capillary gas chromatograph equipped with a surface ionization detector (SID). Urinary FT was determined quantitatively in the range of 0.4-40 ng/ml using deuterium labeled FT (FT-{sup 2}H{sub 19}), as an internal standard. We also performed isotope dilution analysis of Nor-FT in urine. N-Alkylation was necessary to sensitively detect Nor-FT with SID. Methyl derivative was selected from 3 kinds of N-alkyl derivatives to increase sensitivity and peak resolution, and to prevent interference with urinary compound. Nor-FT concentration was quantitatively determined in the range of 10-400 ng/ml using deuterium labeled Nor-FT (Nor-FT-{sup 2}H{sub 10}). No endogenous compounds or concomitant drugs interfered with the detection of FT and Nor-FT in the urine of patients. The present method will be useful for pharmacokinetic studies and the evaluation of drug interactions in FT metabolism. (author)

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

    Science.gov (United States)

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

    2016-05-20

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

  14. Electrophoretic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates: Application to proenkephalin processing enzymes

    International Nuclear Information System (INIS)

    A novel method is described for the zymographic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates such as [35S]methionine-labeled proenkephalin or 125I-labeled proinsulin. After electrophoresis the enzyme is reactivated and cleaves the radiolabeled in situ substrate into smaller peptides. These small peptides are able to diffuse out of the gel, leaving clear areas against a dark background when visualized by autoradiography. The technique can be used to detect as little as 200 fg of trypsin using only 50 ng (1.25 microCi) of [35S]proenkephalin. Soluble- and membrane-bound adrenal trypsin-like enzyme were isolated from bovine adrenal chromaffin granules. Both proteinases cleaved [35S]methionine-labeled proenkephalin but not 125I-labeled proinsulin. Moreover, both had a Mr of approximately 30,000. The potential of this technique for general use is discussed. An additional method using the synthetic fluorogenic substrate t-butoxycarbonyl Glu-Lys-Lys aminomethylcoumarin is also described

  15. Electrophoretic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates: Application to proenkephalin processing enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Irvine, J.W.; Roberts, S.F.; Lindberg, I. (Louisiana State Univ. Medical Center, New Orleans (USA))

    1990-10-01

    A novel method is described for the zymographic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates such as ({sup 35}S)methionine-labeled proenkephalin or {sup 125}I-labeled proinsulin. After electrophoresis the enzyme is reactivated and cleaves the radiolabeled in situ substrate into smaller peptides. These small peptides are able to diffuse out of the gel, leaving clear areas against a dark background when visualized by autoradiography. The technique can be used to detect as little as 200 fg of trypsin using only 50 ng (1.25 microCi) of ({sup 35}S)proenkephalin. Soluble- and membrane-bound adrenal trypsin-like enzyme were isolated from bovine adrenal chromaffin granules. Both proteinases cleaved ({sup 35}S)methionine-labeled proenkephalin but not {sup 125}I-labeled proinsulin. Moreover, both had a Mr of approximately 30,000. The potential of this technique for general use is discussed. An additional method using the synthetic fluorogenic substrate t-butoxycarbonyl Glu-Lys-Lys aminomethylcoumarin is also described.

  16. A lateral electrophoretic flow diagnostic assay

    OpenAIRE

    Lin, Robert; Skandarajah, Arunan; Gerver, Rachel E.; Neira, Hector D.; Daniel A Fletcher; Herr, Amy E.

    2015-01-01

    Immunochromatographic assays are a cornerstone tool in disease screening. To complement existing lateral flow assays (based on wicking flow) we introduce a lateral flow format that employs directed electrophoretic transport. The format is termed a “lateral e-flow assay” and is designed to support multiplexed detection using immobilized reaction volumes of capture antigen. To fabricate the lateral e-flow device, we employ mask-based UV photopatterning to selectively immobilize unmodified captu...

  17. A lateral electrophoretic flow diagnostic assay

    OpenAIRE

    Lin, R.; Skandarajah, A.; Gerver, RE; Neira, HD; Fletcher, DA; Herr, AE

    2015-01-01

    © 2015 The Royal Society of Chemistry. Immunochromatographic assays are a cornerstone tool in disease screening. To complement existing lateral flow assays (based on wicking flow) we introduce a lateral flow format that employs directed electrophoretic transport. The format is termed a "lateral e-flow assay" and is designed to support multiplexed detection using immobilized reaction volumes of capture antigen. To fabricate the lateral e-flow device, we employ mask-based UV photopatterning to ...

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

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

  19. Recent innovations in protein separation on microchips by electrophoretic methods.

    Science.gov (United States)

    Peng, Youyuan; Pallandre, Antoine; Tran, N Thuy; Taverna, Myriam

    2008-01-01

    Microchips for analytical purposes have attracted great attention over the last 20 years. In the present review, we focus on the most recent development of microchips for electrophoretic separation of proteins. This review starts with a short recalling about the microchips covering the basic microchip layout for CE and the commercial chips and microchip platforms. A short paragraph is dedicated to the surface treatment of microchips, which is of paramount importance in protein analysis. One section is dedicated to on-line sample pretreatment in microchips and summarizes different strategies to pre-concentrate or to purify proteins from complex matrixes. Most of the common modes used for CE of proteins have already been adapted to the chip format, while multidimensional approaches are still in progress. The different routes to achieve detection in microchip are also presented with a special attention to derivatization or labeling of proteins. Finally, several recent applications are mentioned. They highlight the great potential of electrophoretic separations of proteins in numerous fields such as biological, pharmaceutical or agricultural and food analysis. A bibliography with 151 references is provided covering papers published from 2000 to the early 2007.

  20. Analysis of Gums by Capillary Electrophoresis with Laser Induced Fluorescence%毛细管电泳分离和激光检测分析多糖胶

    Institute of Scientific and Technical Information of China (English)

    彭加瑜; SANDRA Pat

    2004-01-01

    将多糖胶的混合物与荧光剂9-氨基芘-1,4,6-三磺酸(APTS)派生后再进行微量离心过滤分离.所得到的高分子部分采用毛细管电泳(CE)分离和激光诱导荧光(LIF)检测技术进行分析.缓冲溶液pH的调节和聚丙烯酰胺(PAA)涂层毛细管的使用有效地改善了多糖胶的分离效率和峰形.在优化条件下,iota、kappa角叉菜胶、藻胶、xanthan、carboxymethyl cellulose (CMC)等5种组分的混合物和阿拉伯树胶、刺梧桐树胶、CMC等3种组分的混合物分别在pH 3.2和7.8的缓冲溶液下得到了完整组分的分离.这被认为是一种分析多糖胶的既简单快速又有效的方法.%Gums were derivatised with the fluorescence reagent, 9-aminopyrene-1,4,6-trisulfonic acid followed by microcentrifuge filtration. The resulting high mass fractions were analysed by capillary electrophoresis (CE) on a polyacrylamide coated capillary with laser induced fluorescence (LIF) detection. A wide pH range of electrolytes was used to study the influences on the electrophoretic mobilities and on the peak shapes of the gums. In this way, the separation of a mixture of five commercial gums, namely iota carrageenan, kappa carrageenan, alginic acid, xanthan and carboxymethyl cellulose (CMC), could be achieved at pH 3.2 with a 25 mmol/L trisodium citrate buffer. It is also shown that a mixture of Arabic gum, Karaya gum and CMC could be separated at pH 7.8 in a similar buffer.

  1. Analysis of a ribonuclease H digestion of N3'-->P5' phosphoramidate-RNA duplexes by capillary gel electrophoresis.

    Science.gov (United States)

    DeDionisio, L; Gryaznov, S M

    1995-07-01

    Phosphodiester oligonucleotides (ODNs) and their analogs are presently being investigated as potential antisense therapeutics in the treatment of viral infections and various forms of cancer. here, we would like to report results from an investigation of activity for a ribonuclease H (RNase H) mediated RNA digestion assay in the duplexes formed by an ODN or the ODN analog, N3'-->P5' phosphoramidate (3'-phosphoramidate), and complimentary RNA strands. Capillary gel electrophoresis (CGE) proved to be an effective method for determining RNA hydrolysis in the presence of RNase H. RNA and an ODN or RNA and a 3'-phosphoramidate were hybridized in a Tris-HCl, MgCl2 buffer at room temperature (RT) and incubated with RNase H. Digestions were carried out at RT or at 37 degrees C. Control samples were unhybridized RNA with RNase H, RNA without RNase H, and duplexes (RNA-ODN or 3'-phosphoramidate) without RNase H. All controls were incubated in Tris-HCl, MgCl2 buffer, and sample aliquots were analyzed at various time intervals. A homodecamer, (dT)10, was used as an internal standard to determine the relative migration time of the RNA strand. The final digestion products for the duplexes and the various controls were monitored by CGE. In addition, polyacrylamide gel electrophoresis (PAGE) was used in conjunction with Stains-All (staining) and a densitometric analysis to verify CGE results. PMID:7581876

  2. Clinical features and imaging findings in pulmonary capillary hemangiomatosis: report of two cases and a pooled analysis

    Institute of Scientific and Technical Information of China (English)

    XIE Wan-mu; DAI Hua-ping; JIN Mu-lan; WANG Zhen; YANG Yuan-hua; ZHAI Zhen-guo; WANG Chen

    2012-01-01

    Background Pulmonary capillary hemangiomatosis (PCH) is a rare disease and no Chinese case has been reported yet.The disease is often misdiagnosed and its clinical characteristics are incompletely described.The aim of this study was to describe two Chinese cases and to clarify the clinical and radiographic parameters of patients with PCH.Methods Two PCH cases were presented and other cases were searched from the English literature.All available clinical and radiographic data were collected from 62 literature reported PCH cases.A pooled analysis of total 64 cases was made.Results Dyspnea and hemoptysis were the most common clinical symptoms of PCH.Pulmonary hypertension (PH)was found in 78% of the reported cases.PCH typically showed characteristic diffuse or patchy ground-glass opacities (GGOs) and/or multiple ill-defined centrilobular nodules in the computed tomography.Conclusions The diagnosis of PCH requires a high clinical suspicion.However,both clinical presentations and radiographic studies often provide clues to the diagnosis,which may prompt early lung biopsy for a definite diagnosis.

  3. Luminescent electrophoretic particles via miniemulsion polymerization for night-vision electrophoretic displays.

    Science.gov (United States)

    Meng, Xianwei; Wen, Ting; Qiang, Li; Ren, Jun; Tang, Fangqiong

    2013-05-01

    A novel glowing electrophoretic display (EPD) is achieved by luminescent electrophoretic particles (EPs), which is potentially to improve the situation in which the existing EPDs disable in darkness. To combine both modes of reflective and emissive displays, a trilayer luminescence EP is designed and synthesized via an improved miniemulsion polymerization. The luminescence EP is composed of a pigment core, a polystyrene interlayer, and a fluorescent coating. The particle sizes are from 140 to 170 nm, and the size distribution is narrow. Their ζ potential value is -12.4 mV, which is enough to migrate in the electrophoretic fluid by the driving of an electric field. The display performance of the particles in an EPD cell has been characterized under the bias of 20 V. Both the reflectance (491 nm) and fluorescence (521 nm) intensities of the EPD cell remained in a constant range after 30 switches. PMID:23547950

  4. Quality by design in the chiral separation strategy for the determination of enantiomeric impurities: development of a capillary electrophoresis method based on dual cyclodextrin systems for the analysis of levosulpiride.

    Science.gov (United States)

    Orlandini, S; Pasquini, B; Del Bubba, M; Pinzauti, S; Furlanetto, S

    2015-02-01

    Quality by design (QbD) concepts, in accordance with International Conference on Harmonisation Pharmaceutical Development guideline Q8(R2), represent an innovative strategy for the development of analytical methods. In this paper QbD principles have been comprehensively applied in the set-up of a capillary electrophoresis method aimed to quantify enantiomeric impurities. The test compound was the chiral drug substance levosulpiride (S-SUL) and the developed method was intended to be used for routine analysis of the pharmaceutical product. The target of analytical QbD approach is to establish a design space (DS) of critical process parameters (CPPs) where the critical quality attributes (CQAs) of the method have been assured to fulfil the desired requirements with a selected probability. QbD can improve the understanding of the enantioseparation process, including both the electrophoretic behavior of enantiomers and their separation, therefore enabling its control. The CQAs were represented by enantioresolution and analysis time. The scouting phase made it possible to select a separation system made by sulfated-β-cyclodextrin and a neutral cyclodextrin, operating in reverse polarity mode. The type of neutral cyclodextrin was included among other CPPs, both instrumental and related to background electrolyte composition, which were evaluated in a screening phase by an asymmetric screening matrix. Response surface methodology was carried out by a Doehlert design and allowed the contour plots to be drawn, highlighting significant interactions between some of the CPPs. DS was defined by applying Monte-Carlo simulations, and corresponded to the following intervals: sulfated-β-cyclodextrin concentration, 9-12 mM; methyl-β-cyclodextrin concentration, 29-38 mM; Britton-Robinson buffer pH, 3.24-3.50; voltage, 12-14 kV. Robustness of the method was examined by a Plackett-Burman matrix and the obtained results, together with system repeatability data, led to define a method

  5. Capillary ion chromatography with on-column focusing for ultra-trace analysis of methanesulfonate and inorganic anions in limited volume Antarctic ice core samples.

    Science.gov (United States)

    Rodriguez, Estrella Sanz; Poynter, Sam; Curran, Mark; Haddad, Paul R; Shellie, Robert A; Nesterenko, Pavel N; Paull, Brett

    2015-08-28

    Preservation of ionic species within Antarctic ice yields a unique proxy record of the Earth's climate history. Studies have been focused until now on two proxies: the ionic components of sea salt aerosol and methanesulfonic acid. Measurement of the all of the major ionic species in ice core samples is typically carried out by ion chromatography. Former methods, whilst providing suitable detection limits, have been based upon off-column preconcentration techniques, requiring larger sample volumes, with potential for sample contamination and/or carryover. Here, a new capillary ion chromatography based analytical method has been developed for quantitative analysis of limited volume Antarctic ice core samples. The developed analytical protocol applies capillary ion chromatography (with suppressed conductivity detection) and direct on-column sample injection and focusing, thus eliminating the requirement for off-column sample preconcentration. This limits the total sample volume needed to 300μL per analysis, allowing for triplicate sample analysis with <1mL of sample. This new approach provides a reliable and robust analytical method for the simultaneous determination of organic and inorganic anions, including fluoride, methanesulfonate, chloride, sulfate and nitrate anions. Application to composite ice-core samples is demonstrated, with coupling of the capillary ion chromatograph to high resolution mass spectrometry used to confirm the presence and purity of the observed methanesulfonate peak.

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

    Science.gov (United States)

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

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

  7. Rapid enantioseparation of amlodipine by highly sulfated cyclodextrins using short-end injection capillary electrophoresis

    Directory of Open Access Journals (Sweden)

    M Zandkarimi

    2009-12-01

    Full Text Available "n  "n Background and the purpose of the study:The use of highly sulfated cyclodextrins (HS-CDs as chiral selectors in capillary electrophoresis (CE has been examined for rapid and reproducible enantioseparation of the model drug amlodipine, a calcium channel blocker. "nMaterials and Methods: Fused silica capillaries with an inner diameter of 50 μm, and a total length of 45.5 cm (8.5 cm to the detector were used. Capillaries were rinsed with polyethylene oxide (PEO once daily. A systematic method development approach was conducted by modifying selected parameters such as the type and concentration of the chiral selector, the buffer pH and concentration of the background electrolyte. "nResults: Baseline separation was achieved at low (i.e. 0.05%w/v concentrations of HS-αCD, but migration time and peak area repeatability were more than 4% and 25% of the relative standard deviation (RSD, respectively. At higher concentrations (>0.3% of HS-αCD, amlodipine was transported to the anode by the carrier ability of HS-αCD. In carrier mode, the migration order of enantiomers was reversed, the migration time was reduced and the peak area repeatability of analysis was improved. The optimum electrophoretic conditions for the stereoselective analysis of amlodipine were obtained in carrier mode with 25 mM sodium phosphate buffer containing 1.25% w/v of HS-αCD at pH 2.5 with an applied voltage of +15 kV. Under these conditions migration time was less than 3 min and within-day migration time and peak area repeatability, were less than 0.4% and 2.1% RSD, respectively. Conclusions: Rapid enantioseparation was achieved with minimum variation in quantitative analysis. These optimized conditions are appropriate for the enantioselective analysis of amlodipine.

  8. Modeling and Analysis of the Electrokinetic Mass Transport and Adsorption Mechanisms of a Charged Adsorbate in Capillary Electrochromatography Systems Employing Charged Nonporous Adsorbent Particles.

    Science.gov (United States)

    Grimes, B. A.; Liapis, A. I.

    2001-02-01

    Mass-transfer systems based on electrokinetic phenomena (i.e., capillary electrochromatography (CEC)) have shown practical potential for becoming powerful separation methods for the biotechnology and pharmaceutical industries. A dynamic mathematical model, consisting of the momentum balance and the Poisson equations, as well as the unsteady-state continuity expressions for the cation and anion of the background electrolyte and of a positively charged analyte (adsorbate), is constructed and solved to determine quantitatively the electroosmotic velocity, the electrostatic potential, the concentration profiles of the charged species in the double layer and in the electroneutral core region of the fluid in the interstitial channels for bulk flow in the packed chromatographic column, and the axial current density profiles as the adsorbate adsorbs onto the negatively charged fixed sites on the surface of the nonporous particles packed in the chromatographic column. The frontal analysis mode of operation is simulated in this work. The results obtained from model simulations provide significant physical insight into and understanding of the development and propagation of the dynamic profile of the concentration of the adsorbate (analyte) and indicate that sharp, highly resolved adsorption fronts and large amounts of adsorbate in the adsorbed phase for a given column length can be obtained under the following conditions: (i) The ratio, gamma(2, 0), of the electroosmotic velocity of the mobile liquid phase at the column entrance after the adsorption front has passed the column entrance to the electrophoretic velocity of the anion is very close to -1. The structure of the equations of the model and model simulations indicate that a stable adsorption front cannot develop when gamma(2, 0) is less than -1 unless the value of the mobility of the cation is less than the value of the mobility of the analyte, which may be a rare occurrence in practical CEC systems. (ii) The ratio of

  9. Establishment of fingerprint of active fraction from dried body of Catharsius molossus by capillary electrophoresis and analysis by its total quantum statistical moment%蜣螂有效部位毛细管电泳指纹图谱的建立及其总量统计矩分析

    Institute of Scientific and Technical Information of China (English)

    马家骅; 谭承佳; 赵云生; 贺福元; 杨明

    2013-01-01

    目的 建立蜣螂有效部位的毛细管电泳(CE)指纹图谱,探讨利用总量统计矩法分析指纹图谱的可行性.方法 采用毛细管区带电泳法(CZE),以弹性石英毛细管柱(60 cm×75 μm)为分离通道,75 mmol/L硼砂溶液(pH 9.8)作缓冲液,运行电压+20 kV,检测波长200 nm,指纹图谱的评价采用药典委员会相似度分析软件与总量统计矩法.结果 建立了蜣螂有效部位的CE指纹图谱,药典委员会的相似度软件与总量统计矩法计算的相似度基本一致,显示蜣螂有效部位批间差异小.结论 建立的CE指纹图谱准确简便、重现性好,可作为蜣螂提取物的质量控制方法,而总量统计矩法可以作为指纹图谱的分析方法.%Objective To establish capillary electrophoresis (CE) fingerprint of active fraction from the dried body of Catharsius molossus and to explore the feasibility of fingerprint evaluation by total quantum statistical moment method.Methods Capillary zone electrophoresis (CZE) was used.The electrophoretic conditions were as follows:fused silica capillary column (60 cm × 75 μm),borate solution (75 mmol/L,pH 9.8) as the running buffer,applied voltage of +20 kV,and the detection wavelength of 200 nm.Fingerprint was evaluated by similarity analysis software of Pharmacopeia Committee and total quantum statistical moment method.Results The CE fingerprint of active fraction from the dried body of C.molossus was established.The similarities in six batches of the active fractions evaluated by similarity analysis software of Pharmacopeia Committee and total quantum statistical moment method had no significant difference.Conclusion The method is accurate,simple,and reproducible.It could be used for the quality control of active fraction from the dired body of C.molossus.The total quantum statistical moment method could be used to analyze the fingerprint.

  10. High-Throughput and Low-Cost Analysis of Trace Volatile Phthalates in Seafood by Online Coupling of Monolithic Capillary Adsorbent with GC-MS.

    Science.gov (United States)

    Insuan, Wimonrut; Khawmodjod, Phatchara; Whitlow, Harry J; Soonthondecha, Peerapong; Malem, Fairda; Chienthavorn, Orapin

    2016-04-27

    A simple, sensitive, and high-throughput method was developed for the determination of six volatile phthalate esters-dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)-in seafood samples by using monolith adsorbent in a capillary coupled to a gas chromatography-mass spectrometry (GC-MS) system. The freeze-dried samples were subjected to an ultrasonication with hexane, followed by vortex mixing. The liquid extract was quantitatively determined by a direct application to an online silica monolith capillary adsorbent coupled with a gas chromatograph with mass spectrometric detection. Method validation in seafood matrix gave recoveries of 72.8-85.4% and a detection limit of 6.8-10.0 ng g(-1) for bivalve samples. Reusability of the monolith capillary for trapping coextracted matrix was up to six times, allowing high-throughput analysis at the parts per billion level. When compared with the Food and Environment Research Agency (FERA) method, no significant difference in the result was observed, confirming the method was valid and applicable for the routine analysis of phthalates in seafood samples for food and environmental laboratories. PMID:27082024

  11. High-Throughput and Low-Cost Analysis of Trace Volatile Phthalates in Seafood by Online Coupling of Monolithic Capillary Adsorbent with GC-MS.

    Science.gov (United States)

    Insuan, Wimonrut; Khawmodjod, Phatchara; Whitlow, Harry J; Soonthondecha, Peerapong; Malem, Fairda; Chienthavorn, Orapin

    2016-04-27

    A simple, sensitive, and high-throughput method was developed for the determination of six volatile phthalate esters-dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)-in seafood samples by using monolith adsorbent in a capillary coupled to a gas chromatography-mass spectrometry (GC-MS) system. The freeze-dried samples were subjected to an ultrasonication with hexane, followed by vortex mixing. The liquid extract was quantitatively determined by a direct application to an online silica monolith capillary adsorbent coupled with a gas chromatograph with mass spectrometric detection. Method validation in seafood matrix gave recoveries of 72.8-85.4% and a detection limit of 6.8-10.0 ng g(-1) for bivalve samples. Reusability of the monolith capillary for trapping coextracted matrix was up to six times, allowing high-throughput analysis at the parts per billion level. When compared with the Food and Environment Research Agency (FERA) method, no significant difference in the result was observed, confirming the method was valid and applicable for the routine analysis of phthalates in seafood samples for food and environmental laboratories.

  12. Laser-based capillary polarimeter.

    Science.gov (United States)

    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

  13. Enantioselective analysis of proteinogenic amino acids in cerebrospinal fluid by capillary electrophoresis-mass spectrometry.

    Science.gov (United States)

    Prior, Amir; Sánchez-Hernández, Laura; Sastre-Toraño, Javier; Marina, Maria Luisa; de Jong, Gerhardus J; Somsen, Govert W

    2016-09-01

    d-Amino acids (AAs) are increasingly being recognized as essential molecules in biological systems. Enantioselective analysis of proteinogenic AAs in biological samples was accomplished by CE-MS employing β-CD as chiral selector and ESI via sheath-liquid (SL) interfacing. Prior to analysis, AAs were fully derivatized with FMOC, improving AA-enantiomer separation and ESI efficiency. In order to optimize the separation and MS detection of FMOC-AAs, the effects of type and concentration of CD in the BGE, the composition of the SL, and MS-interfacing parameters were evaluated. Using a BGE of 10 mM β-CD in 50 mM ammonium bicarbonate (pH 8) containing 15% v/v isopropanol, a SL of isopropanol-water-1 M ammonium bicarbonate (50:50:1, v/v/v) at a flow rate of 3 μL/min, and a nebulizer gas pressure of 2 psi, 15 proteinogenic AAs could be detected with enantioresolutions up to 3.5 and detection limits down to 0.9 μM (equivalent to less than 3 pg AA injected). The selectivity of the method was demonstrated by the analysis of spiked cerebrospinal fluid, allowing specific detection of d-AAs. Repeatability and linearity obtained for cerebrospinal fluid were similar to standard solutions, with peak area and migration-time RSDs (n = 5) below 16.2 and 1.6%, respectively, and a linear response (R(2) ≥ 0.977) in the 3-90 μM range. PMID:27465690

  14. Theoretical Analysis of the Pressure Oscillation Phenomena in Capillary Pumped Loop

    Institute of Scientific and Technical Information of China (English)

    ZhangJiaxun; HouZengqi; 等

    1998-01-01

    Based on the physical model of caplillary pumped loop(CPL)system,the phenomena of pressure oscillation are simplified and analyzed.From a set of non-linear differential equations,the influence of ststem parameters on the performance of the CPL is discussed,including the working temperature (the set point),loop resistance,vapor volume etc.From the analysis,some measures were taken to improve the performance of the loop,Meanwhile ,the reason why the deprive of the CPL occurs during the operation is given by analyzing the theoretical calculation results.

  15. A simple method for assessment and minimization of errors in determination of electrophoretic or electroosmotic mobilities and velocities associated with the axial electric field distortion.

    Science.gov (United States)

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

    2015-12-01

    It is commonly accepted that the modern CE instruments equipped with efficient cooling system enable accurate determination of electrophoretic or electroosmotic mobilities. It is also often assumed that velocity of migration in a given buffer is constant throughout the capillary length. It is simultaneously neglected that the noncooled parts of capillary produce extensive Joule heating leading to an axial electric field distortion, which contributes to a difference between the effective and nominal electric field potentials and between velocities in the cooled and noncooled parts of capillary. This simplification introduces systematic errors, which so far were however not investigated experimentally. There was also no method proposed for their elimination. We show a simple and fast method allowing for estimation and elimination of these errors that is based on combination of a long-end and short-end injections. We use it to study the effects caused by variation of temperature, electric field, capillary length, and pH.

  16. Capillary Electrophoretic Analysis of Amnesic Shellfish Toxin-Domoic Acid%记忆缺失性贝类毒素的主要成分——软骨藻酸的毛细管电泳分析

    Institute of Scientific and Technical Information of China (English)

    李大志; 祝文君; 宋文斌; 林炳承

    2002-01-01

    通过萃取、离子交换等技术,建立了毛细管电泳/紫外检测法分析海洋赤潮生物毒素的重要种类之一、记忆缺失性贝类毒素的主要成分软骨藻酸的方法.结果表明:软骨藻酸在0.2 mg/L~50 mg/L时具有良好的线性关系,相关系数r=0.999*!0;方法检出限为0.063 mg/L(S/N>3).在3个添加水平上进行加标回收试验(n=6),平均回收率分别为97.24%,96.92%和97.55%,RSD分别为2.74%,2.59%和1.95%.利用该方法对5种经济贝类样品进行了测定.该方法简单、灵敏、高效、成本低,对软骨藻酸的检测和监控具有重要意义.

  17. Electrophoretic mobilities of dissolved polyelectrolyte charging agent and suspended non-colloidal titanium during electrophoretic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Kok-Tee [School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76109 Durian Tunggal, Melaka (Malaysia); Sorrell, C.C., E-mail: C.Sorrell@unsw.edu.au [School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

    2011-03-25

    Coarse ({<=}20 {mu}m) titanium particles were deposited on low-carbon steel substrates by cathodic electrophoretic deposition (EPD) with ethanol as suspension medium and poly(diallyldimethylammonium chloride) (PDADMAC) as polymeric charging agent. Preliminary data on the electrophoretic mobilities and electrical conductivities on the suspensions of these soft particles as well as the solutions themselves as a function of PDADMAC level were used as the basis for the investigation of the EPD parameters in terms of the deposition yield as a function of five experimental parameters: (a) PDADMAC addition level, (b) solids loading, (c) deposition time, (d) applied voltage, and (e) electrode separation. These data were supported by particle sizing by laser diffraction and deposit surface morphology by scanning electron microscopy (SEM). The preceding data demonstrated that Ti particles of {approx}1-12 {mu}m size, electrosterically modified by the PDADMAC charging agent, acted effectively as colloidal particles during EPD. Owing to the non-colloidal nature of the particles and the stabilization of the Ti particles by electrosteric forces, the relevance of the zeta potential is questionable, so the more fundamental parameter of electrophoretic mobility was used. A key finding from the present work is the importance of assessing the electrophoretic mobilities of both the suspensions and solutions since the latter, which normally is overlooked, plays a critical role in the ability to interpret the results meaningfully. Further, algebraic uncoupling of these data plus determination of the deposit yield as a function of charging agent addition allow discrimination between the three main mechanistic stages of the electrokinetics of the process, which are: (1) surface saturation; (2) compression of the diffuse layer, growth of polymer-rich layer, and/or competition between the mobility of Ti and PDADMAC; and (3) little or no decrease in electrophoretic mobility of Ti

  18. CSE-MECC two-dimensional capillary electrophoresis analysis of proteins in the mouse tumor cell (AtT-20) homogenate

    OpenAIRE

    Chen, Xingguo; Fazal, Md. Abul; Dovichi, Norman J.

    2007-01-01

    Two-dimensional capillary electrophoresis was used for the separation of proteins and biogenic amines from the mouse AtT-20 cell line. The first-dimension capillary contained a TRIS-CHES-SDS-dextran buffer to perform capillary sieving electrophoresis, which is based on molecular weight of proteins. The second-dimension capillary contained a TRIS-CHES-SDS buffer for micel1ar electrokinetic capillary chromatography. After a 61 seconds preliminary separation, fractions from the first-dimension c...

  19. Analysis of thiols by microchip capillary electrophoresis for in situ planetary investigations.

    Science.gov (United States)

    Mora, Maria F; Stockton, Amanda M; Willis, Peter A

    2013-01-01

    The detection of thiols on extraterrestrial bodies could provide evidence for life, as well as a host of potential prebiological or abiological processes. Here, we report a novel protocol to analyze organic thiols by microchip CE with LIF detection. Thiols were labeled with Pacific Blue C5 maleimide and analyzed by MEKC. The separation buffer consisted of 15 mM tetraborate pH 9.2 and 25 mM SDS. The optimized method provided LODs ranging from 1.4 to 15 nM. The method was validated using samples collected from geothermal pools at Hot Creek Gorge, California, which were found to contain 2-propanethiol and 1-butanethiol in the nanomolar concentration range. These samples serve as chemical analogues to material potentially present in the reducing environment of primitive Earth and also at sulfurous regions of Mars. Hence, the protocol developed here enables highly sensitive thiol analysis in samples with complexity comparable to that expected in astrobiologically relevant extraterrestrial settings. This new protocol could be readily added to the existing suite of microfluidic chemical analyses developed for in situ planetary exploration; all that is required is the incorporation of two new reagents to the payload of an existing instrument concept. PMID:23161601

  20. In-capillary formation of polymer/surfactant complexes-assisted reversed-migration micellar electrokinetic chromatography for facile analysis of neutral steroids.

    Science.gov (United States)

    Wu, Li-Chen; Hu, Ching-Yuan; Dung, Yi-Shiou; Wu, Tsung-Hung

    2013-03-30

    In this study we developed a novel approach, using in-capillary formation of polymer/surfactant complexes (IPSC)-assisted reversed-migration MEKC (RM-MEKC), for the analysis of neutral steroids. This process involved two sequential events: in-capillary polymer/surfactant complexes formation during sample preconcentration, followed by IPSC separation. The procedure began with a polymer-filled capillary. Initially, on-line preconcentration of the sample was performed at the sample plug. Meanwhile, free surfactants migrated to interact with polymers, forming polymer-surfactant complexes. Analytes were then kinetically partitioned between the mixed phases (micelles and polymer-SDS complexes). Sodium dodecyl sulfate (SDS) and poly(N-isopropylacrylamide) (PNIPAAm) were employed as pseudo-stationary phases (PSPs). This system allowed the successful separation of five steroids (testosterone, hydrocortisone 21-acetate, dexamethasone, prednisolone, hydrocortisone) in acetate buffer and the determination of urinary free hydrocortisone; it also exhibited excellent performance for sample on-line concentration. The limit of detection for hydrocortisone was 20.98 ng/mL (R(2)=0.9995). The polymer size, concentrations, end-group charges, and SDS concentrations were evaluated. This IPSC/RM-MEKC system, which can be adopted in commercial CE instruments, is easy to operate, suitable for combination with several sample preconcentration options, sensitive, robust, and environmentally sustainable. We suspect that such systems might have potential applications in clinical analyses and in microanalytical devices. PMID:23598239

  1. Forensic ancestry analysis with two capillary electrophoresis ancestry informative marker (AIM) panels: Results of a collaborative EDNAP exercise.

    Science.gov (United States)

    Santos, C; Fondevila, M; Ballard, D; Banemann, R; Bento, A M; Børsting, C; Branicki, W; Brisighelli, F; Burrington, M; Capal, T; Chaitanya, L; Daniel, R; Decroyer, V; England, R; Gettings, K B; Gross, T E; Haas, C; Harteveld, J; Hoff-Olsen, P; Hoffmann, A; Kayser, M; Kohler, P; Linacre, A; Mayr-Eduardoff, M; McGovern, C; Morling, N; O'Donnell, G; Parson, W; Pascali, V L; Porto, M J; Roseth, A; Schneider, P M; Sijen, T; Stenzl, V; Court, D Syndercombe; Templeton, J E; Turanska, M; Vallone, P M; van Oorschot, R A H; Zatkalikova, L; Carracedo, Á; Phillips, C

    2015-11-01

    There is increasing interest in forensic ancestry tests, which are part of a growing number of DNA analyses that can enhance routine profiling by obtaining additional genetic information about unidentified DNA donors. Nearly all ancestry tests use single nucleotide polymorphisms (SNPs), but these currently rely on SNaPshot single base extension chemistry that can fail to detect mixed DNA. Insertion-deletion polymorphism (Indel) tests have been developed using dye-labeled primers that allow direct capillary electrophoresis detection of PCR products (PCR-to-CE). PCR-to-CE maintains the direct relationship between input DNA and signal strength as each marker is detected with a single dye, so mixed DNA is more reliably detected. We report the results of a collaborative inter-laboratory exercise of 19 participants (15 from the EDNAP European DNA Profiling group) that assessed a 34-plex SNP test using SNaPshot and a 46-plex Indel test using PCR-to-CE. Laboratories were asked to type five samples with different ancestries and detect an additional mixed DNA sample. Statistical inference of ancestry was made by participants using the Snipper online Bayes analysis portal plus an optional PCA module that analyzes the genotype data alongside calculation of Bayes likelihood ratios. Exercise results indicated consistent genotyping performance from both tests, reaching a particularly high level of reliability for the Indel test. SNP genotyping gave 93.5% concordance (compared to the organizing laboratory's data) that rose to 97.3% excluding one laboratory with a large number of miscalled genotypes. Indel genotyping gave a higher concordance rate of 99.8% and a reduced no-call rate compared to SNP analysis. All participants detected the mixture from their Indel peak height data and successfully assigned the correct ancestry to the other samples using Snipper, with the exception of one laboratory with SNP miscalls that incorrectly assigned ancestry of two samples and did not obtain

  2. Determination of vanillin in vanilla perfumes and air by capillary electrophoresis.

    Science.gov (United States)

    Minematsu, Saaya; Xuan, Guang-Shan; Wu, Xing-Zheng

    2013-12-01

    The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364 μm, inner diameter: 50 μm) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0-10(-2) mol/L. The detection limit was about 10(-5) mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10(-4) mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated. PMID:25078845

  3. Determination of vanillin in vanilla perfumes and air by capillary electrophoresis.

    Science.gov (United States)

    Minematsu, Saaya; Xuan, Guang-Shan; Wu, Xing-Zheng

    2013-12-01

    The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364 μm, inner diameter: 50 μm) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0-10(-2) mol/L. The detection limit was about 10(-5) mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10(-4) mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated.

  4. Electrochemically powered self-propelled electrophoretic nanosubmarines

    Science.gov (United States)

    Pumera, Martin

    2010-09-01

    In the past few years, we have witnessed rapid developments in the realization of the old nanotechnology dream, autonomous nanosubmarines. These nanomachines are self-powered, taking energy from their environment by electrocatalytic conversion of chemicals present in the solution, self-propelled by flux of the electrons within the submarine and the hydronium ions on the surface of the nanosub, powering it in the direction opposite to that of the flux of the hydronium. These nanosubmarines are responsive to external fields, able to follow complex magnetic patterns, navigate themselves in complex microfluidic channels, follow chemical gradients, carry cargo, and communicate with each other. This minireview focuses on a discussion of the fundamentals of the electrophoretic mechanism underlying the propulsion of this sort of nanosub, as well as a demonstration of the proof-of-concept capabilities of nanosubmarines.In the past few years, we have witnessed rapid developments in the realization of the old nanotechnology dream, autonomous nanosubmarines. These nanomachines are self-powered, taking energy from their environment by electrocatalytic conversion of chemicals present in the solution, self-propelled by flux of the electrons within the submarine and the hydronium ions on the surface of the nanosub, powering it in the direction opposite to that of the flux of the hydronium. These nanosubmarines are responsive to external fields, able to follow complex magnetic patterns, navigate themselves in complex microfluidic channels, follow chemical gradients, carry cargo, and communicate with each other. This minireview focuses on a discussion of the fundamentals of the electrophoretic mechanism underlying the propulsion of this sort of nanosub, as well as a demonstration of the proof-of-concept capabilities of nanosubmarines. In memory of Karel Zeman, Czech animator, who encouraged thousands of young people into science and technology, on the occasion of the 100th

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

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, C.A.

    1995-12-31

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

  6. Intramedullary capillary haemangioma.

    LENUS (Irish Health Repository)

    Kelleher, T

    2012-02-03

    Intramedullary capillary haemangioma is extremely rare and only four cases have been previously reported. We describe a further case, outlining the clinical, radiological, surgical and pathological features.

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

    OpenAIRE

    Herrero, Miguel; Arráez-Román, David; Segura-Carretero, Antonio; Kendler, Ernst; Gius, Beatrice; Raggi, Maria Augusta; Ibáñez, Elena; Cifuentes, Alejandro

    2005-01-01

    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 concentrati...

  8. Optimization of capillary electrophoresis method with contactless conductivity detection for the analysis of tobramycin and its related substances.

    Science.gov (United States)

    El-Attug, Mohamed Nouri; Hoogmartens, Jos; Adams, Erwin; Van Schepdael, Ann

    2012-01-25

    A method was validated and optimized to determine tobramycin (TOB) and its related substances. TOB is an aminoglycoside antibiotic which lacks a strong UV absorbing chromophore or fluorophore. Due to the physicochemical properties of TOB, capillary electrophoresis (CE) in combination with Capacitively Coupled Contactless Conductivity Detection (C(4)D) was chosen. The optimized separation method uses a background electrolyte (BGE) composed of 25 mM morpholinoethane-sulphonic acid (MES) adjusted to pH 6.4 by L-histidine (l-His). 0.3 mM cetyltrimethyl ammonium bromide (CTAB) was added as electroosmotic flow modifier in a concentration below the critical micellar concentration (CMC). Ammonium acetate 50 mg L(-1) was used as internal standard (IS). 30 kV was applied in reverse polarity (cathode at the injection capillary end) on a fused silica capillary (65/43 cm; 75 μm id). The optimized separation was obtained in less than 7 min with good linearity (R(2)=0.9995) for tobramycin. It shows a good precision expressed as RSD on relative peak areas equal to 0.2% and 0.7% for intraday and interday respectively. The LOD and LOQ are 0.4 and 1.3 mg L(-1) corresponding to 9 pg and 31 pg respectively. PMID:22015240

  9. Applications of capillary electrophoresis and laser-induced fluorescence detection to the analysis of trace species: From single cells to single molecules

    Energy Technology Data Exchange (ETDEWEB)

    Qifeng, X.

    1995-11-01

    This Ph.D. Thesis describes several separation and detection schemes for the analysis of small volume and amount of samples, such as intracellular components and single enzymes developed during research. Indirect Laser-induced fluorescence detection and capillary electrophoresis were used to quantify lactate and pyruvate in single red blood cells. The assay of specific enzyme activities was achieved by monitoring the highly fluorescent enzymatic reaction product, NADH. LDH activity was found not to be a unique marker for diagnosis of leukemia. Reactions of single LDH-1 molecules were investigated by monitoring the reaction product with LIF detection.

  10. Cyclodextrine Screening for the Chiral Separation of Amlodipine Enantiomers by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Gabriel Hancu

    2015-03-01

    Full Text Available Purpose: Amlodipine is a long acting, dihydropyridine type calcium channel blocker frequently used in the treatment of hypertension and coronary insufficiency. The calcium channel blocking activity resides primarily in the S-amlodipine enantiomer, while R-amlodipine is a potent inhibitor of smooth muscle cell migration. Methods: In this study capillary electrophoresis was applied for the enantiomeric separation of amlodipine using different native and derivatized; neutral and charged cyclodextrines as chiral selectors. The effects of pH and composition of the background electrolyte, concentration and type of chiral selector, capillary temperature, running voltage and injection parameters have been investigated. Results: Stereoselective interactions were observed when using α-CD, β-CD, HP-β-CD, RAMEB, CM-β-CD and SBE-β-CD. Optimized separation conditions consisted on a 50 mM phosphate buffer, pH – 3.0, 20 mM RAMEB as chiral selector, + 25 kV applied voltage, 15°C temperature and UV detection at 238 nm. Using the optimized electrophoretic conditions we succeeded the chiral separation of amlodipine enantiomers in approximately 6 minute, the order of migration being R-amlodipine followed by S-amlodipine. The method was successfully applied for the determination of amlodipine enantiomers from commercially available pharmaceuticals. The linearity range, limits of detection and quantification, precision and accuracy were determined and the results obtained confirmed that the method was suitable for this purpose. Conclusion: It can be concluded that the proposed capillary electrophoresis methods can be useful for routine pharmaceutical applications with benefits of its effectivity, simplicity, short analysis time and low consumption of analytes, solvents and chiral selectors.

  11. Determination of antazoline and tetrahydrozoline in ophthalmic solutions by capillary electrophoresis and stability-indicating HPLC methods.

    Science.gov (United States)

    Gumustas, Mehmet; Alshana, Usama; Ertas, Nusret; Goger, Nilgun Gunden; Ozkan, Sibel A; Uslu, Bengi

    2016-05-30

    Capillary electrophoretic (CE) and high performance liquid chromatographic (HPLC) methods were developed and optimized for the determination of antazoline (ANT) and tetrahydrozoline (TET) in ophthalmic formulations. Optimum electrophoretic conditions were achieved using a background electrolyte of 20mM phosphate buffer at pH 7.0, a capillary temperature of 25°C, a separation voltage of 22kV and a pressure injection of the sample at 50mbar for 17s. HPLC analysis was performed with Kinetex (150×4.6mm ID×5μm) (Phenomenex, USA) analytical column with 1mLmin(-1) flow rate of mobile phase which consisted of 0.05% TFA in bidistilled water (pH adjusted to 3.0 with 5M NaOH) and acetonitrile/buffer in the ratio of 63:37 (v/v) at room temperature. Injection volume of the samples was 10μL and the wavelength of the detector was set at 215nm for monitoring both analytes. Calibration graphs showed a good linearity with a coefficient of determination (R(2)) of at least 0.998 for both methods. Intraday and interday precision (expressed as RSD%) were lower than 2.8% for CE and 0.92% for HPLC. The developed methods were demonstrated to be simple and rapid for the determination of ANT and TET in ophthalmic solutions providing recoveries in the range between 97.9 and 102.70% for CE and HPLC. PMID:26952922

  12. Capillary zone electrophoretic determination of phenolic compounds in chess (Bromus inermis L.) plant extracts.

    Science.gov (United States)

    Sterbová, Dagmar; Vlcek, Jirí; Kubán, Vlastimil

    2006-02-01

    A simple CZE method for quantification of phenolic compounds (vanillin, cinnamic, sinapic, chlorogenic, syringic, ferulic, benzoic, p-coumaric, vanillic, p-hydroxybenzoic, rosmarinic, caffeic, gallic and protocatechuic acids) in less than 10 min using 20 mM sodium tetraborate (pH 9.2) with 5% v/v methanol as a BGE and with UV detection at 254 nm is described. The LODs (3 S/N) ranged between 0.02 and 0.12 microg/ mL. Repeatabilities (RSDs) were 0.66-1.8 and 1.56-4.23% for migration times and peak areas (n = 5), respectively. The method was applied to the determination of phenolic compounds in chess (Bromus inermis L.) after Soxhlet extraction and purification of the crude extracts with SPE procedures. The results compared well with those obtained by liquid chromatographic method. B. inermis was found as a suitable model plant containing a broad spectrum of phenolic compounds in easily detectable concentrations and as a potential source of antioxidants. PMID:16524108

  13. Characterization and performance of a neutral hydrophilic coating for the capillary electrophoretic separation of biopolymers.

    Science.gov (United States)

    Schmalzing, D; Piggee, C A; Foret, F; Carrilho, E; Karger, B L

    1993-10-15

    Polyvinylmethylsiloxanediol (50% vinyl) was synthesized and combined with a cross-linker for static coating onto fused-silica columns. After cross-linking and binding to the surface, linear polyacrylamide was grafted to the double bonds of the siloxanediol; subsequently, this linear polymer matrix was cross-linked with formaldehyde. The grafted neutral polymeric layer provided suppression of electroosmotic flow and minimized adsorption. This combination yielded successful open tube and polymer network separations of proteins, peptides and DNA molecules. Very high efficiencies (ca. 1 x 10(6) plates/m) were achieved for open tube protein separations, and hundreds of consecutive runs were performed with minimal change in migration times.

  14. High Performance Wafer-Based Capillary Electrochromatography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II research comprises designing, constructing, and testing a chip-based capillary electrochromatography (CEC) prototype for separation and analysis of...

  15. Monolithic molecular imprinted polymer fiber for recognition and solid phase microextraction of ephedrine and pseudoephedrine in biological samples prior to capillary electrophoresis analysis.

    Science.gov (United States)

    Deng, Dong-Li; Zhang, Ji-You; Chen, Chen; Hou, Xiao-Ling; Su, Ying-Ying; Wu, Lan

    2012-01-01

    A novel capillary electrophoresis (CE) method coupled with monolithic molecular imprinted polymer (MIP) fiber based solid phase microextraction (SPME) was developed for selective and sensitive determination of ephedrine (E) and pseudoephedrine (PE). With in situ polymerization in a silica capillary mold and E as template, the MIP fibers could be produced in batch reproducibly and each fiber was available for 50 extraction cycles without significant decrease in extraction ability. Using the MIP fiber under optimized extraction conditions, CE detection limits of E and PE were greatly lowered from 0.20 to 0.00096 μg/mL and 0.12 to 0.0011 μg/mL, respectively. Analysis of urine and serum samples by the MIP-SPME-CE method was also performed, with results indicating that E and PE could be selectively extracted. The recoveries and relative standard deviations (RSDs) for sample analysis were found in the range of 91-104% and 3.8-9.1%, respectively.

  16. Microencapsulated Electrophoretic Films for Electronic Paper Displays

    Science.gov (United States)

    Amundson, Karl

    2003-03-01

    Despite the dominance of liquid crystal displays, they do not perform some functions very well. While backlit liquid crystal displays can offer excellent color performance, they wash out in bright lighting and suffer from high power consumption. Reflective liquid crystal displays have limited brightness, making these devices challenging to read for long periods of time. Flexible liquid crystal displays are difficult to manufacture and keep stable. All of these attributes (long battery lifetime, bright reflective appearance, compatibility with flexible substrates) are traits that would be found in an ideal electronic paper display - an updateable substitute for paper that could be employed in electronic books, newspapers, and other applications. I will discuss technologies that are being developed for electronic-paper-like displays, and especially on particle-based technologies. A microencapsulated electrophoretic display technology is being developed at the E Ink corporation. This display film offers offer high brightness and an ink-on-paper appearance, compatibility with flexible substrates, and image stability that can lead to very low power consumption. I will present some of the physical and chemical challenges associated with making display films with high performance.

  17. New multilayer coating using quaternary ammonium chitosan and κ-carrageenan in capillary electrophoresis: application in fast analysis of betaine and methionine.

    Science.gov (United States)

    Vitali, Luciano; Della Betta, Fabiana; Costa, Ana Carolina O; Vaz, Fernando Antonio Simas; Oliveira, Marcone Augusto Leal; Vistuba, Jacqueline Pereira; Fávere, Valfredo T; Micke, Gustavo A

    2014-06-01

    The aim of this study was to develop a new multilayer coating with crosslinked quaternary ammonium chitosan (hydroxypropyltrimethyl ammonium chloride chitosan; HACC) and κ-carrageenan for use in capillary electrophoresis. A new semi-permanent multilayer coating was formed using the procedure developed and the method does not require the presence of polymers in the background electrolyte (BGE). The new capillary multilayer coating showed a cathodic electroosmotic flow (EOF) of around 30×10(-9) m(2) V(-1) s(-1) which is pH-independent in the range of pH 2 to 10. The enhanced EOF at low pH obtained contributed significantly to the development of a fast method of separation. The multilayer coating was then applied in the development of a fast separation method to determine betaine and methionine in pharmaceutical formulations by capillary zone electrophoresis (CZE). The BGE used to determine the betaine and methionine concentrations was composed of 10 mmol L(-1) tris(hydroxymethyl) aminomethane, 40 mmol L(-1) phosphoric acid and 10% (v/v) ethanol, at pH 2.1. A fused-silica capillary of 32 cm (50 µm ID×375 µm OD) was used in the experiments and samples and standards were analyzed employing the short-end injection procedure (8.5 cm effective length). The instrumental analysis time of the optimized method was 1.53 min (approx. 39 runs per hour). The validation of the proposed method for the determination of betaine and methionine showed good linearity (R(2)>0.999), adequate limit of detection (LOD <8 mg L(-1)) for the concentration in the samples and inter-day precision values lower than 3.5% (peak area and time migration). The results for the quantification of the amino acids in the samples determined by the CZE-UV method developed were statistically equal to those obtained with the comparative LC-MS/MS method according to the paired t-test with a confidence level of 95%. PMID:24725863

  18. Influence of Analyte Concentration on Stability Constant Values Determined by Capillary Electrophoresis.

    Science.gov (United States)

    Sursyakova, Viktoria V; Burmakina, Galina V; Rubaylo, Anatoly I

    2016-08-01

    The influence of analyte concentration when compared with the concentration of a charged ligand in background electrolyte (BGE) on the measured values of electrophoretic mobilities and stability constants (association, binding or formation constants) is studied using capillary electrophoresis (CE) and a dynamic mathematical simulator of CE. The study is performed using labile complexes (with fast kinetics) of iron (III) and 5-sulfosalicylate ions (ISC) as an example. It is shown that because the ligand concentration in the analyte zone is not equal to that in BGE, considerable changes in the migration times and electrophoretic mobilities are observed, resulting in systematic errors in the stability constant values. Of crucial significance is the slope of the dependence of the electrophoretic mobility decrease on the ligand equilibrium concentration. Without prior information on this dependence to accurately evaluate the stability constants for similar systems, the total ligand concentration must be at least >50-100 times higher than the total concentration of analyte. Experimental ISC peak fronting and the difference between the direction of the experimental pH dependence of the electrophoretic mobility decrease and the mathematical simulation allow assuming the presence of capillary wall interaction. PMID:27090731

  19. MICROSPORIDIAN TAXONOMY: APPLICATION OF ELECTROPHORETIC AND IMMUNOLOGICAL TECHNIQUES

    Science.gov (United States)

    A review of investigations utilizing electrophoretic and immunological methods for identification and classification of microsporidians, the group to which the first protozoan microbial pesticide belongs, indicate that these methods can be successfully used to classify strains an...

  20. Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

    Science.gov (United States)

    Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

    2014-03-01

    Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate.

  1. Capillary-Tube Model and Experiment of Multiphase Flow in Capillary Fringes

    Institute of Scientific and Technical Information of China (English)

    武晓峰; 唐杰; 吕贤弼

    2002-01-01

    Contamination of soil and groundwater by organic substances is causing more and more problems worldwide. Analysis of the movement and distribution of nonaqueous phase liquids (NAPLs) in subsurface domain is critical for contaminant remediation. Two-dimensional experiments were conducted in a transparent plexiglass trough (105.0 cm×70.0 cm×1.5 cm) to simulate the release and redistribution of gasoline and kerosene in porous media. The results show that before the contaminant distribution reaches equilibrium, the movement of light NAPLs (LNAPLs) can be divided into four sub-stages. After the contaminant front reaches the upper boundary of the capillary fringe, contaminant movement along the upper boundary of the capillary fringe is the primary transport process. Most of the contaminants then move into the capillary fringe except for the residual part. One-dimensional and two-dimensional capillary tube models were developed to analyze the movement of LNAPLs in the capillary fringe.

  2. Aggregate of Amphiphilic Block Copolymer as a Pseudo-Stationary Phase in Capillary Electrophoresis

    OpenAIRE

    Nakamura, Tohru; OHKI, Akira; Mishiro, Masaki; Tsuyashima, Osamu; Maeda, Shigeru; ナカムラ, トオル; オオキ, アキラ; ミシロ, マサキ; ツヤシマ, オサム; マエダ, シゲル; 中村, 透; 大木, 章; 艶島, 修; 前田, 滋

    1999-01-01

    The use of an aggregate of amphiphilic block copolymer 1, which consists of poly[(N-acetylimino)ethylene] and poly[(N-pentanoylimino)ethylene], for a pseudo-stationary phase in capillary electrophoresis has been examined. From gel-filtration chromatography, the aggregate from 1 (1-AG) was found to incorporate phenol. When the running solution contains 1-AG and sodium dodecyl sulfate (SDS), the electrophoretic mobility becomes nearly zero. Thus, it is found that when 1-AG and SDS are added to ...

  3. Enhanced electrophoretic motion using supercapacitor-based energy storage system.

    Science.gov (United States)

    Liu, Ran; Wong, Flory; Duan, Wentao; Sen, Ayusman

    2013-12-23

    Electrophoretic motion at low potentials is facilitated by redox chemistry occurring in a supercapacitor-based electrochemical energy storage system during charge and discharge. We show that MnO2 -modified electrodes can effectively alleviate the electrode surface polarization, the main factor that leads to inefficient electrophoresis at low voltages. A self-powered electrophoretic system based on a discharging battery has been also fabricated.

  4. Electrophoretic karyotype variation among pathotypes of Fusarium oxysporum f.sp. dianthi

    OpenAIRE

    Migheli, Quirico; Berio, T.; Gullino, Maria Lodovica; Garibaldi, Angelo

    1995-01-01

    Karyotype analysis by pulsed-field gel electrophoresis was applied to characterize isolates of Fusarium oxysporum f.sp. dianthi, the causal agent of Fusarium wilt on carnation. Eleven distinct chromosomal DNA patterns were detected among 38 pathogenic isolates, and the total genome size was estimated to range from 23·7 to 36·4 Mb. Except for isolates belonging to pathotypes 2 and 4, all members of the same pathotype shared overlapping electrophoretic karyotypes. Karyotypes of isolates assigne...

  5. Determination of polyphenols in Spanish wines by capillary zone electrophoresis. Application to wine characterization by using chemometrics.

    Science.gov (United States)

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

    2012-08-29

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

  6. Electrophoretic dynamics of self-assembling branched DNA structures

    Science.gov (United States)

    Heuer, Daniel Milton

    This study advances our understanding of the electrophoretic dynamics of branched biopolymers and explores technologies designed to exploit their unique properties. New self-assembly techniques were developed to create branched DNA for visualization via fluorescence microscopy. Experiments in fixed gel networks reveal a distinct trapping behavior, in contrast with linear topologies. The finding that detection can be achieved by introducing a branch point contributes significantly to the field of separation science and can be exploited to develop new applications. Results obtained in polymer solutions point to identical mobilities for branched and linear topologies, despite large differences in their dynamics. This finding led to a new description of electrophoresis based on non-Newtonian viscoelastic effects in the electric double layer surrounding a charged object. This new theoretical framework presents a new outlook important not only to the electrophoretic physics of nucleic acids, but all charged objects including proteins, colloids, and nanoparticles. To study the behavior of smaller biopolymers, such as restriction fragments and recombination intermediates, a library of symmetrically branched DNA was synthesized followed by characterization in gels. The experimental results contribute a large body of information relating molecular architecture and the dynamics of rigid structures in an electric field. The findings allow us to create new separation technologies based on topology. These contributions can also be utilized in a number of different applications including the study of recombination intermediates and the separation of proteins according to structure. To demonstrate the importance of these findings, a sequence and mutation detection technique was envisioned and applied for genetic analysis. Restriction fragments from mutation "hotspots" in the p53 tumor suppressor gene, known to play a role in cancer development, were analyzed with this technique

  7. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    Science.gov (United States)

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites. PMID:26878711

  8. Authentication of coffee by means of PCR-RFLP analysis and lab-on-a-chip capillary electrophoresis.

    Science.gov (United States)

    Spaniolas, Stelios; May, Sean T; Bennett, Malcolm J; Tucker, Gregory A

    2006-10-01

    Coffee is one of the most important world food commodities, commercial trade consisting almost entirely of Arabica and Robusta varieties. The former is considered to be of superior quality and thus attracts a premium price. Methods to differentiate these coffee species could prove to be beneficial for the detection of either deliberate or accidental adulteration. This study describes a molecular genetics approach to differentiate Arabica and Robusta coffee beans. This employs a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism to monitor a single nucleotide polymorphism within the chloroplastic genome. Samples were analyzed with a lab-on-a-chip capillary electrophoresis system. Coffee powder mixtures were analyzed with this technique, displaying a 5% limit of detection. The plastid copy number was found to be relatively constant across a wide range of bean samples, suggesting that this methodology can also be employed for the quantification of any adulteration of Arabica with Robusta beans. PMID:17002409

  9. [Does bilirubin interfere with capillary electrophoresis of serum proteins?].

    Science.gov (United States)

    Hellara, Ilhem; Fekih, Ons; Triki, Sonia; Elmay, Ahlem; Neffati, Fadoua; Najjar, Mohamed Fadhel

    2014-01-01

    Capillary electrophoresis of serum proteins is a fast, reliable and simple technique, but many interference exist. The objective of our work is to study the interference of bilirubin on this technique; 70 icteric sera were analysed on Capillarys ™ (Sebia). A second electrophoresis was performed on 40 samples after bilirubin photodegradation. The bilirubin and serum proteins were determinated respectively by Jendrassik and Grof and biuret methods on Konélab 20i ™ (Thermo Electron Corporation). We found abnormal spreading of the albumin fraction of the anode side wich constitute sometimes an isolated fraction in the traditional area of pre-albumin migration. This fraction varies from 2.0 ± 2.0% (0.0 to 7.3%) or 0.98 ± 1.53 g/L (0 to 5.3 g/L) and it seems to be related to the direct bilirubin since, following overloading sera with a solution of bilirubin, no further fraction was recovered. An average decrease of bilirubin after photodegradation of 58 ± 17% (26-89%) is followed by a decrease in the same order 64 ± 38% (10-100%) of the additional fraction. Acetate cellulose electrophoresis of the same samples showed no variation. The high bilirubin levels seem modify slightly the electrophoretic profile. However the impact of the interference on the interpretation of electrophoretic trace is negligible. PMID:24492101

  10. Capillary Electrophoresis - Optical Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Cell adhesion during bullet motion in capillaries.

    Science.gov (United States)

    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.

  12. Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE): Lunar Advanced Volatile Analysis (LAVA) Capillary Fluid Dynamic Restriction Effects on Gas Chromatography

    Science.gov (United States)

    Gonzalez, Marianne; Quinn, Jacqueline; Captain, Janine; Santiago-Bond, Josephine; Starr, Stanley

    2015-01-01

    The Resource Prospector (RP) mission with the Regolith and Environment Science and Oxygen Lunar Volatile Extraction (RESOLVE) payload aims to show the presence of water in lunar regolith, and establish a proving ground for NASAs mission to Mars. One of the analysis is performed by the Lunar Advanced Volatiles Analysis (LAVA) subsystem, which consists of a fluid network that facilitates the transport of volatile samples to a gas chromatograph and mass spectrometer (GC-MS) instrument. The understanding of fluid dynamics directed from the GC to the MS is important due to the influence of flow rates and pressures that affect the accuracy of and prevent the damage to the overall GC-MS instrument. The micro-scale capillary fluid network within the GC alone has various lengths and inner-diameters; therefore, determination of pressure differentials and flow rates are difficult to model computationally, with additional complexity from the vacuum conditions in space and lack of a lunar atmosphere. A series of tests were performed on an experimental set-up of the system where the inner diameters of the GC transfer line connecting to the MS were varied. The effect on chromatography readings were also studied by applying these lines onto a GC instrument. It was found that a smaller inner diameter transfer line resulted in a lower flow rate, as well as a lower pressure differential across the thermal conductivity detector (TCD) unit of the GC and a negligible pressure drop across the mock-up capillary column. The chromatography was affected with longer retention times and broader peak integrations. It was concluded that a 0.050 mm inner diameter line still proved most suitable for the systems flow rate preferences. In addition, it was evident that this small transfer line portrayed some expense to GC signal characteristics and the wait time for steady-state operation.

  13. Electrophoretic nanotechnology of composite electrodes for electrochemical supercapacitors.

    Science.gov (United States)

    Su, Y; Zhitomirsky, I

    2013-02-14

    The electrophoretic deposition (EPD) method has been developed for the fabrication of MnO(2)-multiwalled carbon nanotube (MWCNT) films for application in electrochemical supercapacitors (ESs). For MWCNT applications, which depend on electrical conductivity, it is challenging to achieve dispersion and EPD of pristine MWCNT and avoid defects due to chemical treatment or functionalization. An important finding was the possibility of efficient dispersion and controlled EPD of MWCNT using calconcarboxylic acid (CCA). Moreover, the use of CCA allowed efficient dispersion of MnO(2) in concentrated suspensions and EPD of MnO(2) films. The comparison of the experimental data for chromotrope FB (CFB) and CCA and chemical structures of the molecules provided insight into the mechanism of CCA adsorption on MnO(2). The fabrication of stable suspensions of MnO(2) nanoparticles containing MWCNT, and controlled codeposition of both materials is a crucial aspect in the EPD of composites. The new approach was based on the use of CCA as a charging and dispersing agent for EPD of MnO(2) nanoparticles and MWCNT. The deposition yield measurements at various experimental conditions and Fourier transform infrared spectroscopy data, coupled with results of electron microscopy, thermogravimetric, and differential thermal analysis provided evidence of the formation of MnO(2)-MWCNT composites. The electrochemical testing results and impedance spectroscopy data showed good capacitive behavior of the composite films and the beneficial effect of MWCNTs. PMID:22662969

  14. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns; Analisis de Hidrocarburos aromaticos policiclicos. I. Determinacion por cromatografia de gases con columnas capilares de vidrio de silice fundida

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M. M.; Gonzalez, D.

    1987-07-01

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs.

  15. Analysis of regulatory phosphorylation sites in ZAP-70 by capillary high-performance liquid chromatography coupled to electrospray ionization or matrix-assisted laser desorption ionization time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Miliotis, Tasso; Olof Ericsson, Per; Marko-Varga, Gyorgy; Svensson, Robert; Nilsson, Johan; Laurell, Thomas; Bischoff, Rainer

    2001-01-01

    A methodology for the rapid and quantitative analysis of phosphorylation sites in proteins is presented. The coupling of capillary high-performance liquid chromatography (HPLC) to electrospray ionization mass spectrometry (ESI-MS) allowed one to distinguish phosphorylation sites based on retention t

  16. Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Claude, Berengere, E-mail: berengere.claude@univ-orleans.fr [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France); Nehme, Reine; Morin, Philippe [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France)

    2011-08-12

    Highlights: {yields} Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. {yields} The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. {yields} The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. {yields} The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H{sub 3}PO{sub 4}-LiOH (pH 4, ionic strength of 80 mmol L{sup -1}) as running buffer, 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in methanol-water 90/10 (v/v) as sample solvent and 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L{sup -1} concentration range for DA, 3-MT and 5-HT with a determination coefficient (r{sup 2}) higher than 0.99. The limits of quantification (10 nmol L{sup -1} for DA and 3-MT, 5.9 nmol L{sup -1} for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of

  17. Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

    International Nuclear Information System (INIS)

    Highlights: → Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. → The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. → The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. → The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H3PO4-LiOH (pH 4, ionic strength of 80 mmol L-1) as running buffer, 100 μmol L-1 of H3PO4 in methanol-water 90/10 (v/v) as sample solvent and 100 μmol L-1 of H3PO4 in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L-1 concentration range for DA, 3-MT and 5-HT with a determination coefficient (r2) higher than 0.99. The limits of quantification (10 nmol L-1 for DA and 3-MT, 5.9 nmol L-1 for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of neurotransmitters in urine, the presence of salts in the matrix greatly reduces the sensitivity of the FASI

  18. Use of molybdate as novel complex-forming selector in the analysis of polyhydric phenols by capillary zone electrophoresis.

    Science.gov (United States)

    Polásek, Miroslav; Petriska, Ivan; Pospísilová, Marie; Jahodár, Ludek

    2006-03-15

    Molybdate was examined as a complex-forming additive to the CE background electrolytes (BGE) to affect the selectivity of separation of polyhydric phenols such as flavonoids (apigenin, hyperoside, luteolin, quercetin and rutin) and hydroxyphenylcarboxylic acids (ferulic, caffeic, p-coumaric and chlorogenic acid). Effects of the buffer concentrations and pH and the influence of molybdate concentration on the migration times of the analytes were investigated. In contrast to borate (which is a buffering and complex-forming agent generally used in CE at pH > or =9) molybdate forms more stable complexes with aromatic o-dihydroxy compounds and hence the complex-formation effect is observed at considerably lower pH. Model mixtures of cinnamic acid, ferulic acid, caffeic acid and 3-hydroxycinnamic acid were separated with 25 mM morpholinoethanesulfonic acid of pH 5.4 (adjusted with Tris) containing 0.15 mM sodium molybdate as the BGE (25 kV, silica capillary effective length 45 cm x 0.1mm I.D., UV-vis detection at 280 nm). With 25 mM 2-hydroxy-3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulphonic acid/Tris of pH* 7.4 containing 2mM sodium molybdate in aqueous 25% (v/v) methanol as the BGE mixtures of all the above mentioned flavonoids, p-coumaric acid and chlorogenic acid could be separated (the same capillary as above, UV-vis detection at 263 nm). The calibration curves (analyte peak area versus concentration) were rectilinear (r>0.998) for approximately 8-35 microg/ml of an analyte (with 1-nitroso-2-naphthol as internal standard). The limit of quantification values ranged between 1.1 mg l(-1) for p-coumaric acid and 2.8 mg l(-1) for quercetin. The CE method was employed for the assay of flavonoids in medicinal plant extracts. The R.S.D. values ranged between 0.9 and 4.7% (n=3) when determining luteolin (0.08%) and apigenin (0.92%) in dry Matricaria recutita flowers and rutin (1.03%) and hyperoside (0.82%) in dry Hypericum perforatum haulm. The recoveries were >96%. PMID

  19. Determination of the Median Lethal Dose and Electrophoretic Pattern of Hottentotta saulcyi (Scorpiones, Buthidae Scorpion Venom

    Directory of Open Access Journals (Sweden)

    ErsenAydın Yağmur

    2015-10-01

    Full Text Available Background: In this study, we investigated the lethal potency, electrophoretic protein pattern and in vivo effects of Hottentotta saulcyi scorpion venom in mice.Methods: Scorpions were collected at night, by using a UV lamp from Mardin Province, Turkey. Venom was obtained from mature H. saulcyi scorpions by electrical stimulation of the telson. The lethality of the venom was determined by i.v. injections using Swiss mice. In vivo effects of the venom were assessed by using the intraperitoneal route (ip injections into mice (20±1g and monitored for 24 h. The protein profiles of the scorpion venom were analyzed by NuPAGE® Novex® 4–12 % gradient Bis-Tris gel followed by Coomassie blue staining.Results: The lethal assay of the venom was 0.73 mg/kg in mice. We determined the electrophoretic protein pattern of this scorpion venom to be 4, 6, 9, 31, 35, 40, 46 and 69 kDa by SDS-PAGE. Analysis of electrophoresis indicated that H. saulcyi scorpion intoxicated mice exhibited autonomic nervous system symptoms (tachypnea, restlessness, hyperexcitability, convulsions, salivation, lacrimation, weakness.Conclusions: Hottentotta saulcyi scorpion venom includes short-chain neurotoxins and long-chain neurotoxins according to the electrophoretic protein patterns. The stings of H. saulcyi scorpion must be considered of risk for humans in the southeastern region, Turkey.

  20. Sample injection and electrophoretic separation on a simple laminated paper based analytical device.

    Science.gov (United States)

    Xu, Chunxiu; Zhong, Minghua; Cai, Longfei; Zheng, Qingyu; Zhang, Xiaojun

    2016-02-01

    We described a strategy to perform multistep operations on a simple laminated paper-based separation device by using electrokinetic flow to manipulate the fluids. A laminated crossed-channel paper-based separation device was fabricated by cutting a filter paper sheet followed by lamination. Multiple function units including sample loading, sample injection, and electrophoretic separation were integrated on a single paper based analytical device for the first time, by applying potential at different reservoirs for sample, sample waste, buffer, and buffer waste. As a proof-of-concept demonstration, mixed sample solution containing carmine and sunset yellow were loaded in the sampling channel, and then injected into separation channel followed by electrophoretic separation, by adjusting the potentials applied at the four terminals of sampling and separation channel. The effects of buffer pH, buffer concentration, channel width, and separation time on resolution of electrophoretic separation were studied. This strategy may be used to perform multistep operations such as reagent dilution, sample injection, mixing, reaction, and separation on a single microfluidic paper based analytical device, which is very attractive for building micro total analysis systems on microfluidic paper based analytical devices.

  1. Analysis of water from the Space Shuttle and Mir Space Station by ion chromatography and capillary electrophoresis

    Science.gov (United States)

    Orta, D.; Mudgett, P. D.; Ding, L.; Drybread, M.; Schultz, J. R.; Sauer, R. L.

    1998-01-01

    Drinking water and condensate samples collected from the US Space Shuttle and the Russian Mir Space Station are analyzed routinely at the NASA-Johnson Space Center as part of an ongoing effort to verify water quality and monitor the environment of the spacecraft. Water quality monitoring is particularly important for the Mir water supply because approximately half of the water consumed is recovered from humidity condensate. Drinking water on Shuttle is derived from the fuel cells. Because there is little equipment on board the spacecraft for monitoring the water quality, samples collected by the crew are transported to Earth on Shuttle or Soyuz vehicles, and analyzed exhaustively. As part of the test battery, anions and cations are measured by ion chromatography, and carboxylates and amines by capillary electrophoresis. Analytical data from Shuttle water samples collected before and after several missions, and Mir condensate and potable recovered water samples representing several recent missions are presented and discussed. Results show that Shuttle water is of distilled quality, and Mir recovered water contains various levels of minerals imparted during the recovery processes as designed. Organic ions are rarely detected in potable water samples, but were present in humidity condensate samples.

  2. Vibrational analysis of single-layered piezoelectric AFM microcantilever in amplitude mode by considering the capillary force

    Science.gov (United States)

    Habibnejad Korayem, Alireza; Habibnejad Korayem, Moharam; Ghaderi, Reza

    2014-12-01

    In this article, the vibrational behavior of a microcantilever (MC) with an extended piezoelectric layer in the air ambient undergoes examination. To model the vibrational motion of this type of cantilever, the Hamilton's principle has been used. For this purpose, the MC vibrational equation has been derived by the assumption of the continuous beam based on the Euler-Bernoulli beam theory. By adopting the finite element method (FEM), the MC differential equation has been solved. In the present simulation not only van der Waals and contact forces but also the capillary forces resulting from the condensation of the water vapors in air on MC tip have been considered. The results illustrate that the force between the sample surface and the probe affects the MC amplitude; furthermore, it causes the reduction in the resonance frequency. In addition, to reduce the time delay during topography from the surface roughness, it is better to select MCs with larger width and length and smaller thickness. Furthermore, the results indicate that the best imaging takes place when the vibration is in its second vibrational mode. Finally, the effects of MC geometric parameters on the time delay between the starting moment of surface roughness and the moment of variation in the MC amplitude (surface roughness topography) have been analyzed.

  3. Capillary electrophoresis analysis of conventional splicing assays: IARC analytical and clinical classification of 31 BRCA2 genetic variants.

    Science.gov (United States)

    de Garibay, Gorka Ruiz; Acedo, Alberto; García-Casado, Zaida; Gutiérrez-Enríquez, Sara; Tosar, Alicia; Romero, Atocha; Garre, Pilar; Llort, Gemma; Thomassen, Mads; Díez, Orland; Pérez-Segura, Pedro; Díaz-Rubio, Eduardo; Velasco, Eladio A; Caldés, Trinidad; de la Hoya, Miguel

    2014-01-01

    Rare sequence variants in "high-risk" disease genes, often referred as unclassified variants (UVs), pose a serious challenge to genetic testing. However, UVs resulting in splicing alterations can be readily assessed by in vitro assays. Unfortunately, analytical and clinical interpretation of these assays is often challenging. Here, we explore this issue by conducting splicing assays in 31 BRCA2 genetic variants. All variants were assessed by RT-PCR followed by capillary electrophoresis and direct sequencing. If assays did not produce clear-cut outputs (Class-2 or Class-5 according to analytical International Agency for Research on Cancer guidelines), we performed qPCR and/or minigene assays. The latter were performed with a new splicing vector (pSAD) developed by authors of the present manuscript (patent #P201231427 CSIC). We have identified three clinically relevant Class-5 variants (c.682-2A>G, c.7617+1G>A, and c.8954-5A>G), and 27 analytical Class-2 variants (not inducing splicing alterations). In addition, we demonstrate that rs9534262 (c.7806-14T>C) is a BRCA2 splicing quantitative trait locus.

  4. Simultaneous analysis of Cu and Pb as ABEDTA complexes in Rhizoma coptidis by capillary electrophoresis coupled with solid phase extraction

    Institute of Scientific and Technical Information of China (English)

    Fan YunMeng; Ying Qin Wei; Heng Lu; Xin Xin Liu; Jin Xin Liu

    2012-01-01

    A novel capillary electrophoresis method for simultaneous determination of Cu and Pb has been developed in this paper.Cu(Ⅱ)and Pb(Ⅱ) ions were reacted with ABEDTA to form complex to achieve an ideal sensitivity of heavy metal complexes.The digestion solution of Rhizoma coptidis drug sample was purified by neutral Al2O3 column chromatography and the chromatographic behavior of metal-L complexes was investigated.The calibration curve was linear in the range of 5-60 μg/mL for Cu2+ and 5-25 μg/mL for Pb2+ with the correlation coefficients 0.9970 and 0.9972 for each (n =5).The average recoveries were 86.2% for Pb and 90.1% for Cu,while the relative standard deviations were 5.1% and 3.6% respectively.The method was successfully applied to determine Cu and Pb in R.coptidis drug samples.

  5. A comparative analysis of fine-needle capillary cytology vs. fine-needle aspiration cytology in superficial lymph node lesions.

    Science.gov (United States)

    Sajeev, Suraj; Siddaraju, Neelaiah

    2009-11-01

    Fine-needle capillary cytology (FNCC) has been attempted in various organs and studies have shown this procedure to yield qualitatively superior material compared with fine-needle aspiration cytology (FNAC). Studies evaluating the efficacy of this technique in lymph nodes are rare. The present study has attempted to assess the relative advantages and disadvantages of the FNCC technique in comparison to the more widely applied FNAC technique.Thirty enlarged lymph nodes from 26 patients were sampled by both the FNCC and FNAC techniques. The smears obtained were routinely stained by May-Grünwald-Giemsa (MGG) and Papanicolaou staining. The quality of smears was evaluated using an objective scoring system originally devised by Mair et al., for various organs. The score of individual parameters in each case as well as the total scores for FNAC and FNCC procedures were calculated separately and Mann-Whitney's test was performed; a P-value of less than 0.05 was considered significant. Statistical results showed smears obtained by FNCC to be qualitatively better than those obtained by FNAC. Though, individual parameters were not statistically significant, FNCC smears showed better scores as compared with those of FNA smears. Also, the technique was found to be easier to perform and less apprehensive to the patient.Our study convincingly proved the technical superiority of the FNCC technique in cellular lymph node lesions, emphasizing the need for this less publicized procedure to be more widely applied. PMID:19526570

  6. Stacking and Analysis of Melamine in Milk Products with Acetonitrile-Salt Stacking Technique in Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Yu Kong

    2014-01-01

    Full Text Available Melamine was measured in real milk products with capillary electrophoresis (CE based on acetonitrile-salt stacking (ASS method. Real milk samples were deproteinized with acetonitrile at a final concentration of 60% (v/v and then injected hydrodynamically at 50 mBar for 40.0 s. The optimized buffer contains 80.0 mmol/L pH 2.8 phosphates. Melamine could be detected within 20.0 min at +10 kV with a low limit of detection (LOD of 0.03 μmol/L. Satisfactory reproducibility (inter- and intraday RSD% both for migration time and peak area was lower than 5.0% and a wide linearity range of 0.05 μmol/L ~ 10.0 μmol/L were achieved. The proposed method was suitable for routine assay of MEL in real milk samples that was subjected to a simple treatment step.

  7. Gas-Filled Capillary Model

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  8. How Capillary Rafts Sink

    CERN Document Server

    Protiere, S; Aristoff, J; Stone, H

    2010-01-01

    We present a fluid dynamics video showing how capillary rafts sink. 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. Thanks to Archimedes principle we can easily predict whether an object sinks or floats. But what happens when several small particles are placed at an interface between two fluids. In this case surface tension also plays an important role. These particles self-assemble by capillarity and thus form what we call a "capillary raft". We show how such capillary rafts sink for varying sizes of particles and define how this parameter affects the sinking process.

  9. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    Science.gov (United States)

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

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

  10. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

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

    2015-01-01

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

  11. High charged red pigment nanoparticles for electrophoretic displays

    Science.gov (United States)

    Hou, Xin-Yan; Bian, Shu-Guang; Chen, Jian-Feng; Le, Yuan

    2012-12-01

    Organic pigment permanent red F2R nanoparticles were prepared via surface modification to improve the surface charge and dispersion ability in organic medium. Their large surface chargeability is confirmed by ζ-potential value of -49.8 mV. The prepared particles exhibited average size of 105 nm and showed very narrow distribution with polydispersity index of 0.068. The sedimentation ratio of the prepared particles in tetrachloroethylene was less than 5% within 12 days. The electrophoretic inks consisting of the prepared red particles with white particles as contrast showed good electrophoretic display, its refresh time was 200 ms.

  12. Photolithographic process of microcapsule sheet for electrophoretic display

    Energy Technology Data Exchange (ETDEWEB)

    Park, Lee Soon; Choi, Hyung Suk; Kim, Woo-Sik; Lee, Dong-Ho; Min, Kyung-Eun; Seo, Kwan-Ho; Kyu Kang, Inn; Park, Soo-Young; Ho Hwang, Sung; Kwon, Younghwan

    2004-01-05

    A new method of fabricating electrophoretic display sheet was developed utilizing a photolithographic process. In this method, stripe-type barrier ribs with height of 50-80 {mu}m and gap between ribs of 100-150 {mu}m were patterned on the transparent electrode substrate by photolithographic process using a negative-type photoresist. Microspheres dispersed in UV curable monomer system were closely packed into the spaces between the barrier ribs. After laminating the upper ITO film, the resulting sheet was UV-irradiated to give an electrophoretic display panel with uniform packing of microspheres.

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

    Science.gov (United States)

    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

  14. High-throughput molecular determination of salmonella enterica serovars by use of multiplex PCR and capillary electrophoresis analysis.

    Science.gov (United States)

    Leader, Brandon T; Frye, Jonathan G; Hu, Jinxin; Fedorka-Cray, Paula J; Boyle, David S

    2009-05-01

    Salmonella enterica is a leading cause of food-borne illness worldwide and is also a major cause of morbidity and mortality in domestic and wild animals. In the current study, a high-throughput molecular assay was developed to determine the most common clinical and nonhuman serovars of S. enterica in the United States. Sixteen genomic targets were identified based on their differential distribution among common serovars. Primers were designed to amplify regions of each of these targets in a single multiplex PCR while incorporating a 6-carboxyfluorescein-labeled universal primer to fluorescently label all amplicons. The fluorescently labeled PCR products were separated using capillary electrophoresis, and a Salmonella multiplex assay for rapid typing (SMART) code was generated for each isolate, based upon the presence or absence of PCR products generated from each target gene. Seven hundred fifty-one blind clinical isolates of Salmonella from Washington State, collected in 2007 and previously serotyped via antisera, were screened with the assay. A total of 89.6% of the isolates were correctly identified based on comparison to a panel of representative SMART codes previously determined for the top 50 most common serovars in the United States. Of the remaining isolates, 6.2% represented isolates that produced a new SMART code for a previously determined serotype, while the final 8.8% were from serotypes not screened in the original panel used to score isolates in the blinded study. This high-throughput multiplex PCR assay allowed simple and accurate typing of the most prevalent clinical serovars of Salmonella enterica at a level comparable to that of conventional serotyping, but at a fraction of both the cost and time required per test. PMID:19261787

  15. 毛细管电泳技术在检测分析中的应用%Application of Capillary Electrophoresis in Detection Analysis

    Institute of Scientific and Technical Information of China (English)

    关凤华

    2015-01-01

    毛细管电泳技术(CE)作为现今一种主要的分析技术,凭借其高效、灵敏、快速、设备简单、广泛适用性等特点,广泛应用于各个领域.本文简要概述了CE技术的原理及特点,并简述了它在环境分析、食品分析、药物分析、生物大分子分析等各个领域的应用.%Capillary electrophoresis (CE) as a major analytical techniques today, with its efficient, sensitive, rapid, simple equipment, a wide range of applicability and other characteristics, is widely used in various fields. This paper briefly outlines the principles and characteristics of CE technology, and outlines its environmental analysis, food analysis, drug analysis, application of biological macromolecules and other fields.

  16. Capillary electrokinetic separations with optical detection. Technical progress report, February 1, 1993--January 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M.J.

    1998-02-01

    The seminal work of Jorgenson in 1981 ushered in the modern era of capillary electrophoresis (CE). Since that time, research activities involving capillary electrokinetic methods of separation have grown exponentially. Numerous conferences, symposia, monographs, and dedicated journals attest to the maturing of these techniques. While many of the obvious approaches have been explored, and instrumentation is reasonably well-developed, the full potential of CE has clearly not yet been reached. Moreover, CE techniques are not universally accepted as desirable alternatives to traditional chromatographic and electrophoretic methods of separation. Thus, it is likely that research into various aspects of capillary electrokinetic separations will continue at a torrid pace for at least the remainder of this decade.

  17. Capillary permeability in adipose tissue

    DEFF Research Database (Denmark)

    Paaske, W P; Nielsen, S L

    1976-01-01

    of about 7 ml/100 g-min. This corresponds to a capillary diffusion capacity of 2.0 ml/100 g-min which is half the value reported for vasodilated skeletal muscle having approximately twice as great capillary surface area. Thus, adipose tissue has about the same capillary permeability during slight metabolic...

  18. Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.

    1992-06-01

    Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

  19. High-speed DNA genotyping using microfabricated capillary array electrophoresis chips

    Energy Technology Data Exchange (ETDEWEB)

    Woolley, A.T.; Sensabaugh, G.F.; Mathies, R.A. [Univ. of California, Berkeley, CA (United States)

    1997-06-01

    Capillary array electrophoresis (CAE) chips have been designed and fabricated with the capacity to rapidly (<160 s) analyze 12 different samples in parallel. Detection of all lanes with 0.3 s temporal resolution was achieved using a laser-excited confocal-fluorescence scanner. The operation and capabilities of these CAE microdevices were first determined by performing electrophoretic separations of pBR322 MspI DNA samples. Genotyping of HLA-H, a candidate gene for the diagnosis of hereditary hemochromatosis, was then performed to demonstrate the rapid analysis of biologically relevant samples. Two-color multiplex fluorescence detection of HLA-H genotypes was accomplished by prelabeling the standard pBR322 MspI DNA ladder with a red emitting bisintercalation dye (butyl TOTIN) and on-column labeling of the HLA-H DNA with thiazole orange. This work establishes the feasibility of using CAE chips for high-speed, high-throughput genotyping. 44 refs., 7 figs.

  20. A combination of single-drop microextraction and open tubular capillary electrochromatography with carbon nanotubes as stationary phase for the determination of low concentration of illicit drugs in horse urine.

    Science.gov (United States)

    Stege, Patricia W; Lapierre, Alicia V; Martinez, Luis D; Messina, Germán A; Sombra, Lorena L

    2011-10-30

    In this study we developed an interesting alternative to HPLC-mass spectrometry for the quantification of seven important drugs of abuse in racehorses. The procedure proposed in this work is a combination of single-drop microextraction (SDME) and an open tubular capillary electrochromatography (OT-CEC) using multi-wall carbon nanotubes (MWCTs) immobilized into a fused-silica capillary as a stationary phase. The SDME showed to be a powerful tool for extraction/preconcentration of the seven drugs analyzed in the study, showing an enrichment factor between 38- and 102-fold depending on the drug. We have investigated the electrophoretic features of MWCTs immobilized fused-silica capillary by covalent modification of the inner surface of the capillary. The results show a good run-to-run, day-to-day and capillary-to-capillary reproducibility of the method. Compared with the capillary zone electrophoresis (CZE), the coating of the capillary allowed the separation of the analytes with high resolution, with less band-broadening and without distortion of the baseline. The interactions between the analytes and the MWCTs resulted in an increased migration time and probably this was the reason of the front tailing effect. The results showed a good capillary efficiencies and an improved of the electrophoretic separation.

  1. Variations in virulence between different electrophoretic types of Listeria monocytogenes

    DEFF Research Database (Denmark)

    Nørrung, Birgit; Andersen, Jens Kirk

    2000-01-01

    A total of 245 strains of Listeria monocytogenes, representing 33 different electrophoretic types (ETs), were examined quantitatively for haemolytic activity. No significant difference was observed in the mean haemolytic activity between different ETs. Eighty four out of 91 strains examined were...

  2. Surface modification of titanium dioxide for electrophoretic particles

    Institute of Scientific and Technical Information of China (English)

    PENG Xuhui; LE Yuan; BIAN Shuguang; LI Woyuan; WU Wei; DAI Haitao; CHEN Jianfeng

    2007-01-01

    To prepare stable electrophoretic ink (E Ink)needs color particles to be uniformly dispersed in the organic medium.Thus,t-he modification of inorganic particle surface is required.In this paper,Titanium dioxide modified by alumina has been studied.The surface composition and structures of modified particles have been characterized by X-ray photoelectron spectrometer (XPS),X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FT-IR).The dispersibility and electrophoretic mobility of these particles in tetrachloroethylene (TCE) have been investigated by laser particle size analyzer,static sedimentation and electrophoretic instrument.Effects of temperature,pH value and stirring rate on the dispersibility and the charge property of samples have been discussed.The results indicate the settle time of modified TiO2 can last 120 h with the response time of 35 s under the optimized modifying conditions,in which temperature is 85℃-90℃,pH is 8-9 and stirring rate is have been significantly improved,which means that the modified TiO2 is suitable for electrophoretic ink particles.

  3. Electrophoretic Partitioning of Proteins in Two-Phase Microflows

    DEFF Research Database (Denmark)

    Münchow, G.; Hardt, S.; Kutter, Jörg Peter;

    2007-01-01

    conductor and decouples the channel from the electrodes, thus preventing bubble generation inside the separation channel. The experiments show that the electrophoretic transport of proteins between the laminated liquid phases is characterized by a strong asymmetry. When bovine serum albumin (BSA...... increased will the BSA molecules leave the dextran-rich phase almost completely....

  4. Controlled method of reducing electrophoretic mobility of various substances

    Science.gov (United States)

    Vanalstine, James M. (Inventor)

    1989-01-01

    A method of reducing electrophoretic mobility of macromolecules, particles, cells, and the like is provided. The method comprises interacting the particles or cells with a polymer-linked affinity compound composed of: a hydrophilic neutral polymer such as polyethylene glycol, and an affinity component consisting of a hydrophobic compound such as a fatty acid ester, an immunocompound such as an antibody or active fragment thereof or simular macromolecule, or other ligands. The reduction of electrophoretic mobility achieved is directly proportional to the concentration of the polymer-linked affinity compound employed, and the mobility reduction obtainable is up to 100 percent for particular particles and cells. The present invention is advantageous in that analytical electrophoretic separation can not be achieved for macromolecules, particles, and cells whose native surface charge structure had prevented them from being separated by normal electrophoretic means. Depending on the affinity component utilized, separation can be achieved on the basis of specific/irreversible, specific/reversible, semi-specific/reversible, relatively nonspecific/reversible, or relatively nonspecific/irreversible ligand-substance interactions. The present method is also advantageous in that it can be used in a variety of standard laboratory electrophoresis equipment.

  5. Calculation of the electrophoretic mobility of a spherical colloid particle

    NARCIS (Netherlands)

    Wiersema, P.H.; Loeb, A.L.; Overbeek, J.Th.G.

    1966-01-01

    A new calculation of the relation between the electrophoretic mobility and the ζ-potential of a spherical colloid particle is presented. The model consists of a rigid, electrically insulating sphere surrounded by a Gouy-Chapman double layer. The appropriate differential equations (which account for

  6. Electrophoretic deposition of zinc-substituted hydroxyapatite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Guangfei [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ma, Jun, E-mail: caltary@gmail.com [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Shengmin [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-06-01

    Zinc-substituted hydroxyapatite nanoparticles synthesized by the co-precipitation method were used to coat stainless steel plates by electrophoretic deposition in n-butanol with triethanolamine as a dispersant. The effect of zinc concentration in the synthesis on the morphology and microstructure of coatings was investigated. It is found that the deposition current densities significantly increase with the increasing zinc concentration. The zinc-substituted hydroxyapatite coatings were analyzed by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. It is inferred that hydroxyapatite and triethanolamine predominate in the chemical composition of coatings. With the increasing Zn/Ca ratios, the contents of triethanolamine decrease in the final products. The triethanolamine can be burnt out by heat treatment. The tests of adhesive strength have confirmed good adhesion between the coatings and substrates. The formation of new apatite layer on the coatings has been observed after 7 days of immersion in a simulated body fluid. In summary, the results show that dense, uniform zinc-substituted hydroxyapatite coatings are obtained by electrophoretic deposition when the Zn/Ca ratio reaches 5%. - Highlights: • We investigate the Zn/Ca ratios for the synthesis of zinc-substituted HA. • Zinc-substituted HA nanoparticles are used for electrophoretic deposition. • Adding triethanolamine and HCl may aid electrophoretic deposition. • Uniform dense coatings of zinc-substituted HA are obtained when Zn/Ca = 5%.

  7. Electrophoretic separation of kidney and pituitary cells on STS-8

    Science.gov (United States)

    Morrison, D. R.; Nachtwey, D. S.; Barlow, G. H.; Cleveland, C.; Lanham, J. W.; Farrington, M. A.; Hatfield, J. M.; Hymer, W. C.; Todd, P.; Wilfinger, W.; Grindeland, R.; Lewis, M. L.

    A Continuous Flow Electrophoresis System (CFES) was used on Space Shuttle flight STS-8 to separate specific secretory cells from suspensions of cultured primary human embryonic kidney cells and rat pituitary cells. The objectives were to isolate the subfractions of kidney cells that produce the largest amounts of urokinase (plasminogen activator), and to isolate the subfractions of rat pituitary cells that secrete growth hormone, prolactin, and other hormones. Kidney cells were separated into more than 32 fractions in each of two electrophoretic runs. Electrophoretic mobility distributions in flight experiments were spread more than the ground controls. Multiple assay methods confirmed that all cultured kidney cell fractions produced some urokinase, and five to six fractions produced significantly more urokinase than the other fractions. Several fractions also produced tissue plasminogen activator. The pituitary cells were separated into 48 fractions in each of the two electrophoretic runs, and the amounts of growth hormone (GH) and prolactin (PRL) released into the medium for each cell fraction were determined. Cell fractions were grouped into eight mobility classes and immunocytochemically assayed for the presence of GH, PRL, ACTH, LH, TSH, and FSH. The patterns of hormone distribution indicate that the specialized cells producing GH and PRL are isolatable due to the differences in electrophoretic mobilities.

  8. An enhanced capillary electrophoresis method for characterizing natural organic matter.

    Science.gov (United States)

    Cottrell, Barbara A; Cheng, Wei Ran; Lam, Buuan; Cooper, William J; Simpson, Andre J

    2013-02-21

    Natural organic matter (NOM) is ubiquitous and is one of the most complex naturally occurring mixtures. NOM plays an essential role in the global carbon cycle; atmospheric and natural water photochemistry; and the long-range transport of trace compounds and contaminants. There is a dearth of separation techniques capable of resolving this highly complex mixture. To our knowledge, this is the first reported use of ultrahigh resolution counterbalance capillary electrophoresis to resolve natural organic matter. The new separation strategy uses a low pH, high concentration phosphate buffer to reduce the capillary electroosmotic flow (EOF). Changing the polarity of the electrodes reverses the EOF to counterbalance the electrophoretic mobility. Sample stacking further improves the counterbalance separation. The combination of these conditions results in an electropherogram comprised up to three hundred peaks superimposed on the characteristic "humic hump" of NOM. Fraction collection, followed by three-dimensional emission excitation spectroscopy (EEMs) and UV spectroscopy generated a distinct profile of fluorescent and UV absorbing components. This enhanced counterbalance capillary electrophoresis method is a potentially powerful technique for the characterization and separation of NOM and complex environmental mixtures in general. PMID:23289095

  9. Identification of inorganic improvised explosive devices by analysis of postblast residues using portable capillary electrophoresis instrumentation and indirect photometric detection with a light-emitting diode.

    Science.gov (United States)

    Hutchinson, Joseph P; Evenhuis, Christopher J; Johns, Cameron; Kazarian, Artaches A; Breadmore, Michael C; Macka, Miroslav; Hilder, Emily F; Guijt, Rosanne M; Dicinoski, Greg W; Haddad, Paul R

    2007-09-15

    A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris

  10. Electrophoretic Separation of Single Particles Using Nanoscale Thermoplastic Columns.

    Science.gov (United States)

    Weerakoon-Ratnayake, Kumuditha M; Uba, Franklin I; Oliver-Calixte, Nyoté J; Soper, Steven A

    2016-04-01

    Phenomena associated with microscale electrophoresis separations cannot, in many cases, be applied to the nanoscale. Thus, understanding the electrophoretic characteristics associated with the nanoscale will help formulate relevant strategies that can optimize the performance of separations carried out on columns with at least one dimension below 150 nm. Electric double layer (EDL) overlap, diffusion, and adsorption/desorption properties and/or dielectrophoretic effects giving rise to stick/slip motion are some of the processes that can play a role in determining the efficiency of nanoscale electrophoretic separations. We investigated the performance characteristics of electrophoretic separations carried out in nanoslits fabricated in poly(methyl methacrylate), PMMA, devices. Silver nanoparticles (AgNPs) were used as the model system with tracking of their transport via dark field microscopy and localized surface plasmon resonance. AgNPs capped with citrate groups and the negatively charged PMMA walls (induced by O2 plasma modification of the nanoslit walls) enabled separations that were not apparent when these particles were electrophoresed in microscale columns. The separation of AgNPs based on their size without the need for buffer additives using PMMA nanoslit devices is demonstrated herein. Operational parameters such as the electric field strength, nanoslit dimensions, and buffer composition were evaluated as to their effects on the electrophoretic performance, both in terms of efficiency (plate numbers) and resolution. Electrophoretic separations performed at high electric field strengths (>200 V/cm) resulted in higher plate numbers compared to lower fields due to the absence of stick/slip motion at the higher electric field strengths. Indeed, 60 nm AgNPs could be separated from 100 nm particles in free solution using nanoscale electrophoresis with 100 μm long columns. PMID:26963496

  11. Shift dynamics of capillary self-alignment

    NARCIS (Netherlands)

    Arutinov, G.; Mastrangeli, M.; Smits, E.C.P.; Heck, G.V.; Schoo, H.F.M.; Toonder, J.J.M. den; Dietzel, A.H.

    2014-01-01

    This paper describes the dynamics of capillary self-alignment of components with initial shift offsets from matching receptor sites. The analysis of the full uniaxial self-alignment dynamics of foil-based mesoscopic dies from pre-alignment to final settling evidenced three distinct, sequential regim

  12. Thermodynamics of binding of a sulfonamide inhibitor to metal-mutated carbonic anhydrase as studied by affinity capillary electrophoresis.

    Science.gov (United States)

    Sato, Yosuke; Hoshino, Hitoshi; Iki, Nobuhiko

    2015-09-01

    By affinity capillary electrophoresis (ACE), the thermodynamic binding constants of a sulfonamide (SA) inhibitor to bovine carbonic anhydrase II (CA) and metal mutated variants (M-CAs) were evaluated. 1-(4-Aminosulfonylphenylazo)-2-naphthol-6,8-disulfonate was used as the SA in the electrophoretic buffer for ACE. The Scatchard analysis of the dependence of the electrophoretic mobility of native CA on the SA concentration provided the binding constant to be Kb=(2.29±0.05)×10(6) M(-1) (at pH8.4, 25°C). On the other hand, apoCA showed far smaller value [Kb=(3.76±0.14)×10(2) M(-1)], suggesting that the coordination of SA to the Zn(II) center controlled the binding thermodynamics. The ACE of M-CAs showed the same behaviors as native CA but with different Kb values. For example, Co-CA adopting the same tetrahedral coordination geometry as native CA exhibited the largest Kb value [(2.55±0.05)×10(6) M(-1)] among the M-CAs. In contrast, Mn- and Ni-CA, which adopted the octahedral coordination geometry, had Kb values that were about two orders of magnitude lower. Because the hydrophobic cavity of CA around the active center pre-organized the orientation of SA, thereby fixing the ligating NH(-) moiety to the apex of the tetrahedron supported by three basal His3 of CA, metals such as Zn and Co at the center of M-CA gave the most stable CA-SA complex. However, pre-organization was not favored for octahedral geometry. Thus, pre-organization of SA was the key to facilitating the tetrahedral coordination geometry of the Zn(II) active center of CA.

  13. Comparison of Carboxylic and Hydroxycarboxylic Acids as Complexing Agents for Transition Metal Separation with Nonaqueous Capillary Electrophoresis%非水毛细管电泳分离过渡金属羧酸和羟基羧酸配位剂的比较

    Institute of Scientific and Technical Information of China (English)

    屈锋; 林金明

    2004-01-01

    @@ Many papers have been published on the analysis of metal cations by capillary electrophoresis (CE), for example, lanthanide, transition metal, alkali, and alkaline earth metal ions. Separations of metal ions are based on the differences in their electrophoretic mobilities. Since most metal ions having identical charge and size give rise to identical electrophoretic mobilities, the direct electrophoretic separation of these ions is impossible. However, their mobilities can be modified by introducing chemical equilibria in which the ions are involved in forming complexes. If metal ions have different complex formation constants, their apparent electrophoretic mobilities differ. The separation process is mainly carried out by using various weak complexing agents[1-4], which complex the metal ions to different extents. The weak complexing agents for metal ion separation primarily are hydroxycarboxylic acids with hydroxyl and carboxyl groups. In addition, organic solvents have also been added into the electrolytes to improve the selectivity of metal ion separation. When a metal ion interacts with polar solvent molecules through ion-dipole bonds, a solvation shell may be formed around the central ion. In principle, the solvent solvates all kinds of ions in solution, some to a greater extent than others, depending on the specific properties of the central ion regarding a certain solvent. The use of pure nonaqueous systems offers potential for adjustment of relative migration rates via changes in solvent-ion interaction. Evidence for such analyte-electrolyte interaction has been reported for the separations of inorganic anions[5] and alkali, alkaline earth and transition metal ions in pure nonaqueous systems[6-8].

  14. Carboxylated ficolls: preparation, characterization, and electrophoretic behavior of model charged nanospheres.

    Science.gov (United States)

    Guo, Xuhong; Kirton, Gavin F; Dubin, Paul L

    2006-10-26

    Carboxylated ficolls were prepared as model spherical colloids of variable charge and size, with radii ranging from 3.0 to 19.3 nm. Capillary electrophoresis (CE), electrophoretic light scattering (ELS), and potentiometric titration were used to determine mobilities as a function of pH, degree of ionization alpha, and surface potential psi(0). Measured mobilities typically display a plateau at high pH, corresponding to high alpha and psi(0), confirming the general nature of this effect for charged spheres, seen also for charged dendrimers and charged latex particles. This result is examined in the context of a discontinuity in mobility predicted by the Wiersema, O'Brien, and White (WOW) theory and a more recent primitive model electrophoresis (PME) theory, in which bound counterions are considered either as point charges or as hard spheres. While no mobility maximum can be determined as expected by these two theories, our data seem more to support Belloni's theoretical expectations on charged polymers and spheres. Here we explain the mobility plateaus in terms of counterions accumulated close to the surface (surface potential-determining ions) or within the shear plane (mobility-determining ions).

  15. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    OpenAIRE

    Zulkarnain Zainal; Mohd Norizam Md Daud; Azmi Zakaria; Mohd Sabri Mohd Ghazali; Atefeh Jafari; Wan Rafizah Wan Abdullah

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the ...

  16. Correlation of MFOLD-predicted DNA secondary structures with separation patterns obtained by capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) analysis.

    Science.gov (United States)

    Glavac, Damjan; Potocnik, Uros; Podpecnik, Darja; Zizek, Teofil; Smerkolj, Sava; Ravnik-Glavac, Metka

    2002-04-01

    We have studied 57 different mutations within three beta-globin gene promoter fragments with sizes 52 bp, 77 bp, and 193 bp by fluorescent capillary electrophoresis CE-SSCP analysis. For each mutation and wild type, energetically most-favorable predicted secondary structures were calculated for sense and antisense strands using the MFOLD DNA-folding algorithm in order to investigate if any correlation exists between predicted DNA structures and actual CE migration time shifts. The overall CE-SSCP detection rate was 100% for all mutations in three studied DNA fragments. For shorter 52 bp and 77 bp DNA fragments we obtained a positive correlation between the migration time shifts and difference in free energy values of predicted secondary structures at all temperatures. For longer 193 bp beta-globin gene fragments with 46 mutations MFOLD predicted different secondary structures for 89% of mutated strands at 25 degrees C and 40 degrees C. However, the magnitude of the mobility shifts did not necessarily correlate with their secondary structures and free energy values except for the sense strand at 40 degrees C where this correlation was statistically significant (r = 0.312, p = 0.033). Results of this study provided more direct insight into the mechanism of CE-SSCP and showed that MFOLD prediction could be helpful in making decisions about the running temperatures and in prediction of CE-SSCP data patterns, especially for shorter (50-100 bp) DNA fragments.

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

    Science.gov (United States)

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

    2013-12-15

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

  18. Ultrasound-assisted dispersive liquid-liquid microextraction of tetracycline drugs from egg supplements before flow injection analysis coupled to a liquid waveguide capillary cell.

    Science.gov (United States)

    Rodríguez, Michael Pérez; Pezza, Helena Redigolo; Pezza, Leonardo

    2016-09-01

    A simple, rapid, and efficient ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) method was developed for extraction of tetracycline residues from egg supplement samples, with subsequent determination by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell (LWCC) and a controlled temperature heating bath. Tetracyclines react with diazotized p-sulfanilic acid, in a slightly alkaline medium, to form azo compounds that can be measured at 435 nm. The reaction sensitivity improved substantially (5.12-fold) using an in-line heating temperature of 45 °C. Multivariate methodology was used to optimize the factors affecting the extraction efficiency, considering the volumes of extraction and disperser solvents, sonication time, extraction time, and centrifugation time. Good linearity in the range 30-600 μg L(-1) was obtained for all the tetracyclines, with regression coefficients (r) higher than 0.9974. The limits of detection ranged from 6.4 to 11.1 μg L(-1), and the recoveries were in the range 85.7-96.4 %, with relative standard deviation lower than 9.8 %. Analyte recovery was improved by approximately 6 % when the microextraction was assisted by ultrasound. The results obtained with the proposed US-DLLME-FIA method were confirmed by a reference HPLC method and showed that the egg supplement samples analyzed were suitable for human consumption.

  19. Ultrasound-assisted dispersive liquid-liquid microextraction of tetracycline drugs from egg supplements before flow injection analysis coupled to a liquid waveguide capillary cell.

    Science.gov (United States)

    Rodríguez, Michael Pérez; Pezza, Helena Redigolo; Pezza, Leonardo

    2016-09-01

    A simple, rapid, and efficient ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) method was developed for extraction of tetracycline residues from egg supplement samples, with subsequent determination by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell (LWCC) and a controlled temperature heating bath. Tetracyclines react with diazotized p-sulfanilic acid, in a slightly alkaline medium, to form azo compounds that can be measured at 435 nm. The reaction sensitivity improved substantially (5.12-fold) using an in-line heating temperature of 45 °C. Multivariate methodology was used to optimize the factors affecting the extraction efficiency, considering the volumes of extraction and disperser solvents, sonication time, extraction time, and centrifugation time. Good linearity in the range 30-600 μg L(-1) was obtained for all the tetracyclines, with regression coefficients (r) higher than 0.9974. The limits of detection ranged from 6.4 to 11.1 μg L(-1), and the recoveries were in the range 85.7-96.4 %, with relative standard deviation lower than 9.8 %. Analyte recovery was improved by approximately 6 % when the microextraction was assisted by ultrasound. The results obtained with the proposed US-DLLME-FIA method were confirmed by a reference HPLC method and showed that the egg supplement samples analyzed were suitable for human consumption. PMID:27379391

  20. Determination of diethanolamine or N-methyldiethanolamine in high ammonium concentration matrices by capillary electrophoresis with indirect UV detection: application to the analysis of refinery process waters

    Energy Technology Data Exchange (ETDEWEB)

    Bord, N.; Cretier, G.; Rocca, J.-L. [Universite Claude Bernard Lyon 1 (France). Laboratoire des Sciences Analytiques; Bailly, C. [Centre de Recherches de Gonfreville, Total France, Laboratoires Chromatographie Liquide et Microbiologie, Rogerville (France); Souchez, J.-P. [Centre de Recherches de Solaize, Total France, Chemin du Canal, BP 22, St-Symphorien d' Ozon (France)

    2004-09-01

    Alkanolamines such as diethanolamine (DEA) and N-methyldiethanolamine (MDEA) are used in desulfurization processes in crude oil refineries. These compounds may be found in process waters following an accidental contamination. The analysis of alkanolamines in refinery process waters is very difficult due to the high ammonium concentration of the samples. This paper describes a method for the determination of DEA in high ammonium concentration refinery process waters by using capillary electrophoresis (CE) with indirect UV detection. The same method can be used for the determination of MDEA. Best results were achieved with a background electrolyte (BGE) comprising 10 mM histidine adjusted to pH 5.0 with acetic acid. The development of this electrolyte and the analytical performances are discussed. The quantification was performed by using internal standardization, by which triethanolamine (TEA) was used as internal standard. A matrix effect due to the high ammonium content has been highlighted and standard addition was therefore used. The developed method was characterized in terms of repeatability of migration times and corrected peak areas, linearity, and accuracy. Limits of detection (LODs) and quantification (LOQs) obtained were 0.2 and 0.7 ppm, respectively. The CE method was applied to the determination of DEA or MDEA in refinery process waters spiked with known amounts of analytes and it gave excellent results, since uncertainties obtained were 8 and 5%, respectively. (orig.)

  1. Effectiveness of charged noncovalent polymer coatings against protein adsorption to silica surfaces studied by evanescent-wave cavity ring-down spectroscopy and capillary electrophoresis.

    Science.gov (United States)

    Haselberg, Rob; van der Sneppen, Lineke; Ariese, Freek; Ubachs, Wim; Gooijer, Cees; de Jong, Gerhardus J; Somsen, Govert W

    2009-12-15

    Protein adsorption to silica surfaces is a notorious problem in analytical separations. Evanescent-wave cavity ring-down spectroscopy (EW-CRDS) and capillary electrophoresis (CE) were employed to investigate the capability of positively charged polymer coatings to minimize the adsorption of basic proteins. Adsorption of cytochrome c (cyt c) to silica coated with a single layer of polybrene (PB), or a triple layer of PB, dextran sulfate (DS), and PB, was studied and compared to bare silica. Direct analysis of silica surfaces by EW-CRDS revealed that both coatings effectively reduce irreversible protein adsorption. Significant adsorption was observed only for protein concentrations above 400 microM, whereas the PB-DS-PB coating was shown to be most effective and stable. CE analyses of cyt c were performed with and without the respective coatings applied to the fused-silica capillary wall. Monitoring of the electroosmotic flow and protein peak areas indicated a strong reduction of irreversible protein adsorption by the positively charged coatings. Determination of the electrophoretic mobility and peak width of cyt c revealed reversible protein adsorption to the PB coating. It is concluded that the combination of results from EW-CRDS and CE provides highly useful information on the adsorptive characteristics of bare and coated silica surfaces toward basic proteins. PMID:19921852

  2. On-line sequential injection-capillary electrophoresis for near-real-time monitoring of extracellular lactate in cell culture flasks.

    Science.gov (United States)

    Alhusban, Ala A; Gaudry, Adam J; Breadmore, Michael C; Gueven, Nuri; Guijt, Rosanne M

    2014-01-01

    Cell culture has replaced many in vivo studies because of ethical and regulatory measures as well as the possibility of increased throughput. Analytical assays to determine (bio)chemical changes are often based on end-point measurements rather than on a series of sequential determinations. The purpose of this work is to develop an analytical system for monitoring cell culture based on sequential injection-capillary electrophoresis (SI-CE) with capacitively coupled contactless conductivity detection (C(4)D). The system was applied for monitoring lactate production, an important metabolic indicator, during mammalian cell culture. Using a background electrolyte consisting of 25mM tris(hydroxymethyl)aminomethane, 35mM cyclohexyl-2-aminoethanesulfonic acid with 0.02% poly(ethyleneimine) (PEI) at pH 8.65 and a multilayer polymer coated capillary, lactate could be resolved from other compounds present in media with relative standard deviations 0.07% for intraday electrophoretic mobility and an analysis time of less than 10min. Using the human embryonic kidney cell line HEK293, lactate concentrations in the cell culture medium were measured every 20min over 3 days, requiring only 8.73μL of sample per run. Combining simplicity, portability, automation, high sample throughput, low limits of detection, low sample consumption and the ability to up- and outscale, this new methodology represents a promising technique for near real-time monitoring of chemical changes in diverse cell culture applications. PMID:24309712

  3. Evaluation of the performance of single-walled carbon nanohorns in capillary electrophoresis.

    Science.gov (United States)

    Jiménez-Soto, Juan Manuel; Moliner-Martínez, Yolanda; Cárdenas, Soledad; Valcárcel, Miguel

    2010-05-01

    This paper describes for the first time the use of single-walled carbon nanohorns (SWNHs) as pseudostationary and stationary phases for EKC and CEC, respectively, taking advantage of their characteristic features, such as conical-end termination, formation of spherical assemblies dahlia-flower like superstructure and easy functionalization. The use of SWNHs as pseudostationary phase for EKC required the study of their dispersion in different surfactants as well as their compatibility with the electrophoretic system. The carboxylation and subsequent immobilization of carboxylated SWNHs in fused-silica capillary to obtain useful, reproducible and stable stationary phases for CEC has also been investigated, with promising results. The electrophoretic separations obtained for water-soluble vitamins in both modalities (EKC and CEC) have been systematically compared with those obtained with single-walled carbon nanotubes. PMID:20419702

  4. Electrophoretic deposition of silica-hyaluronic acid and titania-hyaluronic acid nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Ma, R. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada); Zhitomirsky, I., E-mail: zhitom@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada)

    2011-06-15

    Research highlights: > The kinetics of electrodeposition of hyaluronic acid has been studied using quartz crystal microbalance. > Composite films containing silica and titania were prepared by electrophoretic deposition. > The deposition yield and deposit composition can be varied by variation of deposition time, voltage and bath composition. > We concluded that the method offers the advantages of room temperature processing for the fabrication of composite materials for biomedical applications. - Abstract: Thin films of hyaluronic acid were prepared by anodic electrophoretic deposition (EPD) and the deposition kinetics was studied using quartz crystal microbalance. EPD method has been developed for the fabrication of new ceramic-biopolymer nanocomposites containing silica and titania nanoparticles in the matrix of hyaluronic acid. The deposit thickness was varied in the range of 0-10 {mu}m. The composition of the deposits can be varied by the variation of silica and titania concentration in the suspensions. The deposits were studied by thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy. The method offers the advantages of room temperature processing of nanocomposite materials for biomedical applications.

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

    Science.gov (United States)

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

    2014-04-25

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

  6. Polyvinylpyrrolidone-sodium dodecylsulfate complex is a family of pseudo-polyanions with different charge densities: Evidence from capillary electrophoresis, capillary viscosimetry and conductometry.

    Science.gov (United States)

    Wu, Yefan; Chen, Jie; Fang, Yun; Zhu, Meng

    2016-10-01

    Accordance with the previously supposed polyelectrolyte-like behaviour of neutral polymer-anionic surfactant complexes, direct evidence for the formation of the pseudo-polyanions in polyvinylpyrrolidone (PVP)-sodium dodecylsulfate (SDS) solution is put forward in this paper by capillary electrophoresis (CE) experiments in assistance with capillary viscosimetry and conductometry. The contradictory phenomena of the absolute value of relative electrophoretic mobility (re) increasing while the ionization degree (α) decreasing with the increasing specific clusterization [Г] in aqueous PVP-SDS solution are explained by the finding that the PVP-SDS complex is eventually a family of PVP-SDS pseudo-polyanions with different charge densities. And it is found countercations playing an important role in the formation of the PVP-SDS pseudo-polyanions in virtue of bridge effect. PMID:27348481

  7. Integrated Microfluidic Isolation of Aptamers Using Electrophoretic Oligonucleotide Manipulation

    OpenAIRE

    Jinho Kim; Olsen, Timothy R.; Jing Zhu; Hilton, John P.; Kyung-Ae Yang; Renjun Pei; Stojanovic, Milan N.; Qiao Lin

    2016-01-01

    We present a microfluidic approach to integrated isolation of DNA aptamers via systematic evolution of ligands by exponential enrichment (SELEX). The approach employs a microbead-based protocol for the processes of affinity selection and amplification of target-binding oligonucleotides, and an electrophoretic DNA manipulation scheme for the coupling of these processes, which are required to occur in different buffers. This achieves the full microfluidic integration of SELEX, thereby enabling ...

  8. Mobility fluctuations and electrophoretic light scattering from macromolecular solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, J.B.; McQuarrie, D.A.

    1988-09-01

    We discuss the origins and the effects of mobility fluctuations of rigid, globular macromolecules on a solution's electrophoretic light scattering spectrum. Assuming a dilute solution, a modified van Hove self-correlation function is calculated via van Kampen's time-ordered cumulant method and the results are compared with less rigorous approaches. The consequences of generalizing to dynamic external fields are briefly considered.

  9. Properties of electrophoretically deposited single wall carbon nanotube films

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Junyoung; Jalali, Maryam; Campbell, Stephen A., E-mail: campb001@umn.edu

    2015-08-31

    This paper describes techniques for rapidly producing a carbon nanotube thin film by electrophoretic deposition at room temperature and determines the film mass density and electrical/mechanical properties of such films. The mechanism of electrophoretic deposition of thin layers is explained with experimental data. Also, film thickness is measured as a function of time, electrical field and suspension concentration. We use Rutherford backscattering spectroscopy to determine the film mass density. Films created in this manner have a resistivity of 2.14 × 10{sup −3} Ω·cm, a mass density that varies with thickness from 0.12 to 0.54 g/cm{sup 3}, and a Young's modulus between 4.72 and 5.67 GPa. The latter was found to be independent of thickness from 77 to 134 nm. We also report on fabricating free-standing films by removing the metal seed layer under the CNT film, and selectively etching a sacrificial layer. This method could be extended to flexible photovoltaic devices or high frequency RF MEMS devices. - Highlights: • We explain the electrophoretic deposition process and mechanism of thin SWCNT film deposition. • Characterization of the SWCNT film properties including density, resistivity, transmittance, and Young's modulus. • The film density and resistivity are found to be a function of the film thickness. • Techniques developed to create free standing layers of SW-CNTs for flexible electronics and mechanical actuators.

  10. Capillary electrophoresis-mass spectrometry-based metabolome analysis of serum and saliva from neurodegenerative dementia patients.

    Science.gov (United States)

    Tsuruoka, Mayuko; Hara, Junko; Hirayama, Akiyoshi; Sugimoto, Masahiro; Soga, Tomoyoshi; Shankle, William R; Tomita, Masaru

    2013-10-01

    Despite increasing global prevalence, the precise pathogenesis and terms for objective diagnosis of neurodegenerative dementias remain controversial, and comprehensive understanding of the disease remains lacking. Here, we conducted metabolomic analysis of serum and saliva obtained from patients with neurodegenerative dementias (n = 10), including Alzheimer's disease, frontotemporal lobe dementia, and Lewy body disease, as well as from age-matched healthy controls (n = 9). Using CE-TOF-MS, six metabolites in serum (β-alanine, creatinine, hydroxyproline, glutamine, iso-citrate, and cytidine) and two in saliva (arginine and tyrosine) were significantly different between dementias and controls. Using multivariate analysis, serum was confirmed as a more efficient biological fluid for diagnosis compared to saliva; additionally, 45 metabolites in total were identified as candidate markers that could discriminate at least one pair of diagnostic groups from the healthy control group. These metabolites possibly provide an objective method for diagnosing dementia-type by multiphase screening. Moreover, diagnostic-type-dependent differences were observed in several tricarboxylic acid cycle compounds detected in serum, indicating that some pathways in glucose metabolism may be altered in dementia patients. This pilot study revealed novel alterations in metabolomic profiles between various neurodegenerative dementias, which would contribute to etiological investigations.

  11. Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

    Energy Technology Data Exchange (ETDEWEB)

    Deen, I. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Zhitomirsky, I., E-mail: zhitom@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2014-02-15

    Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties.

  12. Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

    International Nuclear Information System (INIS)

    Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties

  13. An electrophoretic profiling method for thiol-rich phytochelatins and metallothioneins.

    Science.gov (United States)

    Fan, Teresa W M; Lane, Andrew N; Higashi, Richard M

    2004-01-01

    Thiol-rich peptides such as phytochelatins (PCs) and metallothioneins (MTs) are important cellular chelating agents which function in metal detoxification and/or homeostasis. The variations in molecular sizes and lack of chromophores of these peptides make their analysis difficult. This paper reports an electrophoresis-based method for a broad screen of thiol-rich peptides and proteins. The method uses the thiol-selective fluorescent tag, monobromobimane, coupled with Tricine--sodium dodecyl sulphate--urea polyacrylamide gel electrophoresis for a sensitive determination of both PCs and MTs. Results for PCs were confirmed by two-dimensional NMR and HPLC-tandem MS analyses. Sample throughput is substantially improved over chromatography-based methods through parallel sample analysis in 1 h of electrophoretic separation. The method is versatile in that peptides ranging from glutathione to large proteins can be analysed by simple modification(s) of the extraction and electrophoretic conditions, and the nature of the method supports serendipitous detection of unexpected or novel thiol metabolites.

  14. Electrophoretically-deposited solid film lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Dugger, M.T.; Panitz, J.K.J.; Vanecek, C.W.

    1995-04-01

    An aqueous-based process that uses electrophoresis to attract powdered lubricant in suspension to a charged target was developed. The deposition process yields coatings with low friction, complies with environmental safety regulations, requires minimal equipment, and has several advantages over processes involving organic binders or vacuum techniques. This work focuses on development of the deposition process, includes an analysis of the friction coefficient of the material in sliding contact with stainless steel under a range of conditions, and a functional evaluation of coating performance in a precision mechanical device application. Results show that solid lubricant films with friction coefficients as low as 0.03 can be produced. A 0.03 friction coefficient is superior to solid lubricants with binder systems and is comparable to friction coefficients generated with more costly vacuum techniques.

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

    Directory of Open Access Journals (Sweden)

    Szeliga Jacek

    2011-10-01

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

  16. Separation of acidic and basic proteins by capillary electrophoresis using gemini surfactants and gemini-capped nanoparticles as buffer additives

    Institute of Scientific and Technical Information of China (English)

    LIU Qian; LI YanQing; YANG YanMin; YAO ShouZhuo

    2009-01-01

    This paper demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives in capillary electrophoresis. We showed that even at a low concentration (0.1 mmol·L~(-1)) of alkanediyl-α,ω-bis(dimethyloctadecylammonium bromide) (18-s-18), the wall adsorp-tion of both acidic and basic proteins could be effectively suppressed under acidic conditions. Smaller micelle size (e.g., s=5-8) is more effective for the separation of acidic proteins than larger micelle size (e.g., s 10). Varying the spacer length of gemini surfactants can influence the electrophoretic mobility and selectivity of proteins to achieve the desired separation. Under the optimized conditions, RSDs of the migration time were less than 0.8% and 2.2% for run-to-run and day-to-day assays, re-spectively, and protein recoveries ranged from 79% to 100.4%. Furthermore, we also investigated the use of gemini surfactant-capped gold nanoparticles (gemini@AuNPs) as buffer additives in protein separation. Introduction of AuNPs into the buffer shortened the analysis time and slightly improved the separation efficiencies. Finally, we presented the applications of this method in the analysis of bio-logical samples, including plasma, red blood cells and egg white.

  17. Separation of acidic and basic proteins by capillary electrophoresis using gemini surfactants and gemini-capped nanoparticles as buffer additives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives in capillary electrophoresis. We showed that even at a low concentration (0.1 mmol·L-1) of alkanediyl-α,ω-bis(dimethyloctadecylammonium bromide) (18-s-18), the wall adsorption of both acidic and basic proteins could be effectively suppressed under acidic conditions. Smaller micelle size (e.g., s=5-8) is more effective for the separation of acidic proteins than larger micelle size (e.g., s<4 or >10). Varying the spacer length of gemini surfactants can influence the electrophoretic mobility and selectivity of proteins to achieve the desired separation. Under the optimized conditions, RSDs of the migration time were less than 0.8% and 2.2% for run-to-run and day-to-day assays, respectively, and protein recoveries ranged from 79% to 100.4%. Furthermore, we also investigated the use of gemini surfactant-capped gold nanoparticles (gemini@AuNPs) as buffer additives in protein separation. Introduction of AuNPs into the buffer shortened the analysis time and slightly improved the separation efficiencies. Finally, we presented the applications of this method in the analysis of bio-logical samples, including plasma, red blood cells and egg white.

  18. Utilisation of pH stacking in conjunction with a highly absorbing chromophore, 5-aminofluorescein, to improve the sensitivity of capillary electrophoresis for carbohydrate analysis.

    Science.gov (United States)

    Kazarian, Artaches A; Hilder, Emily F; Breadmore, Michael C

    2008-07-18

    This study explores the use of pH stacking in conjunction with 5-aminofluorescein as a derivatization agent for the sensitive analysis of simple sugars such as glucose, lactose and maltotriose by capillary electrophoresis (CE). The derivatization agent was selected on the basis of its extremely high molar absorptivity, its compatibility with a 488nm light-emitting diode (LED) and the fact that it has two ionizable groups making it compatible with on-line stacking using a dynamic pH junction. The influence of both acetic and formic acids at concentrations of 0.19, 0.019 and 0.0019molL(-1) were investigated with regard to both derivatization efficiency and the ability to stack using a dynamic pH junction. Superior sensitivity and resolution was obtained in formic acid over acetic acid. Substantially lower peaks were obtained with 0.19molL(-1) formic acid when compared to 0.019 and 0.0019molL(-1) concentrations, which was confirmed by computer simulation studies to be due to the inadequate movement of the pH boundary for stacking. Further simulation studies combined with experimental data showed the separation with the best resolution and greatest sensitivity when the carbohydrates were derivatized with the 0.095molL(-1) formic acid. Utilisation of stacking via dynamic pH junction mode in conjunction with LED detection enabled efficiencies of 150,000 plates and detection limits in the order of 8.5x10(-8)molL(-1) for simple sugars such as glucose, lactose and maltotriose hydrate. The current system also demonstrates a 515 times improvement in sensitivity when compared to using a normal deuterium lamp, and 16 times improvement over other systems using LEDs.

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

    Science.gov (United States)

    Anubala, S; Sekar, R; Nagaiah, K

    2014-06-01

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

  20. Capillary Electrophoresis in Food and Foodomics.

    Science.gov (United States)

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

    2016-01-01

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

  1. Carboxylic multi-walled carbon nanotubes as immobilized stationary phase in capillary electrochromatography.

    Science.gov (United States)

    Sombra, Lorena; Moliner-Martínez, Yolanda; Cárdenas, Soledad; Valcárcel, Miguel

    2008-09-01

    Carboxylic multi-walled carbon nanotubes (c-MWNT) have been immobilized into a fused-silica capillary for capillary electrochromatography. The c-MWNT were successfully incorporated after the silanization and coupling with glutaraldehyde on the inner surface of the capillary. The electrochromatographic features of the c-MWNT immobilized stationary phase have been evaluated for the analysis of different compounds of pharmaceutical interest. The results indicated high electrochromatographic resolution, good capillary efficiency and retention factors. In addition, highly reproducible results between runs, days and capillaries were obtained.

  2. Tapered capillary optics

    Science.gov (United States)

    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.

  3. Enantiopurity analysis of new types of acyclic nucleoside phosphonates by capillary electrophoresis with cyclodextrins as chiral selectors.

    Science.gov (United States)

    Solínová, Veronika; Kaiser, Martin Maxmilián; Lukáč, Miloš; Janeba, Zlatko; Kašička, Václav

    2014-02-01

    CE methods have been developed for the chiral analysis of new types of six acyclic nucleoside phosphonates, nucleotide analogs bearing [(3-hydroxypropan-2-yl)-1H-1,2,3-triazol-4-yl]phosphonic acid, 2-[(diisopropoxyphosphonyl)methoxy]propanoic acid, or 2-(phosphonomethoxy)propanoic acid moieties attached to adenine, guanine, 2,6-diaminopurine, uracil, and 5-bromouracil nucleobases, using neutral and cationic cyclodextrins as chiral selectors. With the exception of the 5-bromouracil-derived acyclic nucleoside phosphonate with a 2-(phosphonomethoxy)propanoic acid side chain, the R and S enantiomers of the other five acyclic nucleoside phosphonates were successfully separated with sufficient resolutions, 1.51-2.94, within a reasonable time, 13-28 min, by CE in alkaline BGEs (50 mM sodium tetraborate adjusted with NaOH to pH 9.60, 9.85, and 10.30, respectively) containing 20 mg/mL β-cyclodextrin as the chiral selector. A baseline separation of the R and S enantiomers of the 5-bromouracil-derived acyclic nucleoside phosphonate with 2-(phosphonomethoxy)propanoic acid side chain was achieved within a short time of 7 min by CE in an acidic BGE (20:40 mM Tris/phosphate, pH 2.20) using 60 mg/mL quaternary ammonium β-cyclodextrin chiral selector. The developed methods were applied for the assessment of the enantiomeric purity of the above acyclic nucleoside phosphonates. The preparations of all these compounds were found to be synthesized in pure enantiomeric forms. Using UV absorption detection at 206 nm, their concentration detection limits were in the low micromolar range.

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    QianDONG; XiaoLeiWANG; 等

    2002-01-01

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

  6. Characterization of CNT-MnO2 nanocomposite by electrophoretic deposition as potential electrode for supercapacitor

    Science.gov (United States)

    Darari, Alfin; Ardiansah, Hafidh Rahman; Arifin, Rismaningsih, Nurmanita; Ningrum, Andini Novia; Subagio, Agus

    2016-04-01

    Energy crisis that occured in Indonesia suggests that energy supply could not offset the high rate request and needs an electric energy saving device which can save high voltage, safety, and unlimited lifetime. The weakness of batteries is durable but has a low power density while the capacitor has a high power density but it doesn't durable. The renewal of this study is CNT-MnO2 thin film fabrication method using electrophoretic deposition. Electrophoretic deposition is a newest method to deposited CNT using power supply with cheap, and make a good result. The result of FTIR analysis showed that the best CNT-MnO2 composition is 75:25 and C-C bond is detected in fingerprint area. The result is electrode thin film homogen and characterized by X-ray diffraction (XRD) peaks 2θ=26,63° is characterization of graphite, and 2θ=43,97° is characterization of diamond Carbon type and measured by Scherrer formula results 52,3 nm material average size .EIS test results its capacitance about 7,86 F. from the data it can be concluded that CNT-MnO2 potential electrode very promising for further study and has a potential to be a high capacitance, and fast charge supercapacitor which can be applied for electronic devices, energy converter, even electric car.

  7. Capillary optics for radiation focusing

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Ion guiding in alumina capillaries

    DEFF Research Database (Denmark)

    Juhász, Z.; Sulik, B.; Biri, S.;

    2009-01-01

    Transmission of a few keV impact energy Ne ions through capillaries in anodic alumina membranes has been studied with different ion counting methods using an energy dispersive electrostatic spectrometer, a multichannel plate (MCP) array and sensitive current-measurement. In the present work, we...... focus our attention to the measurements with the MCP array. The alumina capillaries were prepared by electro-chemical oxidation of aluminium foils. For the present experiments guiding of 3-6 keV Ne ions has been studied in two samples with capillary diameter of about 140 nm and 260 nm and with capillary...... length of about 15 μm. At these energies, the ions have been efficiently guided by the capillaries up to few degrees tilt angle. In this work, we compare the results obtained by the energy dispersive spectrometer to those studied by the MCP array. © 2008 Elsevier B.V. All rights reserved....

  9. Biomedical applications of capillary electrophoresis

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-03-11

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

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

    Science.gov (United States)

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

    2016-03-11

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

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

    Science.gov (United States)

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

    2004-10-01

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

  13. DNA mutation detection with chip-based temperature gradient capillary electrophoresis using a slantwise radiative heating system.

    Science.gov (United States)

    Zhang, Hui-Dan; Zhou, Jing; Xu, Zhang-Run; Song, Jin; Dai, Jing; Fang, Jin; Fang, Zhao-Lun

    2007-09-01

    A simple and robust chip-based temperature gradient capillary electrophoresis (TGCE) system was developed for DNA mutation/single-nucleotide polymorphism (SNP) analysis using a radiative heating system. Reproducible, stable and uniform temperature gradients were established along a 3 cm length of the electrophoretic separation channel using a single thermostated aluminium heater plate. The heater was slightly slanted relative to the plane of the glass chip at 0.2-1.3 degrees by inserting thin spacers between the plate and chip at one end to produce differences in radiative heating that created the temperature gradient. On-chip TGCE analyses of 4 mutant DNA model samples amplified from plasmid templates, each containing a single base substitution, with a wide range of melting temperatures, showed that mutations were successfully detected under a wide temperature gradient of 10 degrees C and within a short gradient region of about 3 cm (3.3 degrees C cm(-1) gradient). The radiative heating system was able to establish stable spatial temperature gradients along short microfluidic separation channels using simple peripheral equipment and manipulation while ensuring good resolution for detecting a wide range of mutations. Effectiveness of the system was demonstrated by the successful detection of K-ras gene mutations in 6 colon cancer cell lines.

  14. Electrophoretic separation of kidney and pituitary cells on STS-8

    Science.gov (United States)

    Morrison, D. R.; Nachtwey, D. S.; Barlow, G. H.; Cleveland, C.; Lanham, J. W.; Farrington, M. A.; Hatfield, J. M.; Hymer, W. C.; Grindeland, R.; Lewis, M. L.

    1984-01-01

    Specific secretory cells were separated from suspensions of cultured primary human embryonic cells and rat pituitary cells in microgravity conditions, with an objective of isolating the subfractions of kidney cells that produce the largest amount of urakinase, and the subfractions of rat pituitary cells that secrete growth hormones (GH), prolactin (PRL), and other hormones. It is inferred from the experimental observations that the surface charge distributions of the GH-containing cells differ from those of the PRL-containing cells, which is explained by the presence of secretory products on the surface of pituitary cells. For kidney cells, the electrophoretic mobility distributions in flight experiments were spread more than the ground controls.

  15. Instability of the capillary bridge

    Science.gov (United States)

    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.

  16. Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

    Science.gov (United States)

    Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

    2013-11-01

    Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

  17. Analysis for Flavonoids in Bee Pollens by Capillary Electrophoresis%毛细管电泳法分析蜂花粉中黄酮类化合物

    Institute of Scientific and Technical Information of China (English)

    卢挺; Edward P C Lai; Jorn C C Yu; 胡风祖

    2006-01-01

    使用毛细管电泳法(CE)检测了健康食品中常见的六种黄酮类化合物:橙皮甙、海棠甙、异鼠李素、山奈酚、槲皮素、芦丁.研究了一系列的试验参数,如:pH、缓冲溶液浓度、分离电压以及UV检测器波长等,以确定出最佳条件.使用H3BO3-Na2B4O7缓冲液(pH9.2),各分析物可在8 min内分出.相对标准偏差(RSD):8次进样的迁移时间为0.77%~0.93%;峰面积为3.8%~8.6%;各检测限(S/N=3)范围为0.34 μg/ml~2.9 μ g/ml,回收率为80.4%~113.9%.方法简单、灵敏,重现性高,线性好,无须固相萃取前处理,用于蜂花粉分析结果准确.%A capillary electrophoresis (CE) method has been developed for the determination of six bioactive flavonoids that are commonly found in health foods: hesperidin, hyperin, isorhamnetin, kaempferol, quercetin and rutin. The effects of several parameters, such as pH, buffer concentration, separation voltage and UV detector wavelength, were investigated to find the optimal conditions. Using a H3BO3-Na2B4O7 buffer (pH 9.2), the analytes can be separated within 8 min. The relative standard deviations of migration times in eight injections were between 0.77% and 0.93%, and those of the peak areas ranged from 3.8%to 8.6%. A high reproducibility and excellent linearity was observed over two orders of magnitude, with detection limits (S/N =3) ranging from 0.34 μg ml to 2.9 μg ml for all the six analytes. Recoveries ranged from 80.4 % to 113.9 %. The new method is simple, reproducible and sensitive. No solid phase extraction for sample pretreatment is necessary. Analysis results are accurate in application to bee pollens.

  18. Analysis of [3′,3′-d2]-nicotine and [3′,3′-d2]-cotinine by capillary liquid chromatography-electrospray tandem mass spectrometry

    OpenAIRE

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

    2007-01-01

    A selective and sensitive LC/MS/MS assay was developed for the quantification of d2-nicotine and d2-cotinine in plasma of current and past smokers administered d2-nicotine. After solid phase extraction and liquid liquid extraction, HPLC separation was achieved on a capillary hydrophilic interaction chromatography phase column. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated for d2-nicotine (0.03 to 6.0 ng/...

  19. A Tentative Analysis on the Principle of Capillary Tube Viscometer%试析毛细管黏度计的原理

    Institute of Scientific and Technical Information of China (English)

    秦任甲; 梁玉娟; 张翼

    2009-01-01

    As there is justification showing that Poiseuille's Law is not suited for vertical Capillary tube viscom-eter, Poiseuille's Law has not been used to deduce the calculation formula for measuring liquid viscosity by means of vertical Capillary tube viscometer; it can only be used to deduce the calculation formula for measuring liquid viscosity by horizontal capillary tube viscometer. In this article.we explained the extension of Poiseuille's Law to deduce the Calculation formula for measuring liquid viscosity by using shallow pool and deep pool Capillar tube viscometer, and so corrected the mistakes in using Poiseuille's Law for a long time.%论证表明,泊肃叶定律不适用于直立式毛细管黏度计.因此不能用泊肃叶定律推导直立式毛细管黏度计测定液体黏度的计算公式.泊肃叶定律只能用于推导水平毛细管黏度计测定液体黏度的计算公式.论文阐明用推广的泊肃叶定律推导出浅池直立式和深池直立式毛细管黏度计测定液体黏度的计算公式,纠正了长期以来用泊肃叶定律推导中的错误.

  20. Surface Tension and Capillary Rise

    Science.gov (United States)

    Walton, Alan J.

    1972-01-01

    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  1. Capillary Condensation in Confined Media

    CERN Document Server

    Charlaix, Elisabeth

    2009-01-01

    We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and crack tips) and to their influence on AFM imaging techniques as well as on the static and dynamic friction properties of solids (including granular heaps and sliding nanocontacts). A great attention is spent in investigating the delicate role of the surface roughness and all the difficulties involved in the reduction of the probe size to nanometric dimensions. Another major consequence of capillary condensation in nanosystems is the activation of several chemical and corrosive processes that can significantly alter the surface properties, such as dissolution/redeposition of solid materials and stress-corrosion crack propagati...

  2. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2007-09-01

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

  4. THE DISTRIBUTION OF ELECTROPHORETIC FRACTIONS OF PROTEIN ISOLATES FROM SUNFLOWER MEAL

    Directory of Open Access Journals (Sweden)

    Voronova N. S.

    2014-12-01

    Full Text Available The food status of Russians is characterized by deficiency of protein. Perspective sources of food protein are the secondary resources of the oil and fat industry received when processing seeds of sunflower, including sunflower meal. Unfortunately, the features of technological process at the oilextracting press exclude a possibility of receiving food protein-containing products from them without the additional processing increasing biological value and improving technical characteristics of proteins. On the basis of the above information, the researches of a protein complex of sunflower cake, development of ways of regulation of its functional and technological properties and increase of biological value is up-to-date. The article presents the analysis of the influence of enzymatic modification on the distribution of electrophoretic fractions of the modified protein isolates

  5. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    Zulkarnain Zainal

    2012-05-01

    Full Text Available CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111 orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  6. Electrophoretic deposition of graphene oxide reinforced chitosan-hydroxyapatite nanocomposite coatings on Ti substrate.

    Science.gov (United States)

    Shi, Y Y; Li, M; Liu, Q; Jia, Z J; Xu, X C; Cheng, Y; Zheng, Y F

    2016-03-01

    Electrophoretic deposition (EPD) is a facile and feasible technique to prepare functional nanocomposite coatings for application in orthopedic-related implants. In this work, a ternary graphene oxide-chitosan-hydroxyapatite (GO-CS-HA) composite coating on Ti substrate was successfully fabricated by EPD. Coating microstructure and morphologies were investigated by scanning electron microscopy, contact angle test, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found GO-CS surface were uniformly decorated by HA nanoparticles. The potentiodynamic polarization test in simulated body fluid indicated that the GO-CS-HA coatings could provide effective protection of Ti substrate from corrosion. This ternary composite coating also exhibited good biocompatibility during incubation with MG63 cells. In addition, the nanocomposite coatings could decrease the attachment of Staphylococcus aureus. PMID:26758895

  7. POLYMER-COATED FIBROUS MATERIALS AS THE STATIONARY PHASE IN PACKED CAPILLARY GAS CHROMATOGRAPHY AND THE APPLICATIONS FOR SAMPLE PREPARATION IN ENVIRONMENTAL ANALYSIS%聚合物涂层纤维材料为固定相填充毛细管气相色谱及其在样品预处理中的应用

    Institute of Scientific and Technical Information of China (English)

    SAITOYoshihiro; JINNOKiyokatsu

    2003-01-01

    Fibrous polymers having an excellent heat-resistance were successfully introduced as the stationary phase in capillary gas chromatography (GC) and the basic separation performance has been investigated. Poly(p-phenylene-26-benzobisoxazole); Zylon, fibers were selected as the stationary phase taking into account the chemical structure, heat resistance, solvent resistance and the physical strength. About 330 filaments of the polymer were packed longitudinally into fused-silica capillaries of 0.32 mm i.d., and the GC separation of several test mixtures, such as n-alkylbenzenes and n-alkanes was carried out with these fiber-packed capillary columns. From the results it has been demonstrated that the fiber-packed capillary columns have a great potential as the separation media for volatile compounds. Polymer coating onto the surface of the packed-filaments has been also studied, and the results clearly showed that the retentivity was significantly improved over a conventional capillary columns of the same length and that the selectivity can be tuned by selecting different types of coating materials selected for the purposes. The applications of polymer-coated fiber-packed capillary as a miniaturized sample preparation device was also investigated for the analysis of environmental pollutants in river water samples.

  8. Determination and optimization of the ζ potential in boron electrophoretic deposition on aluminium substrates

    International Nuclear Information System (INIS)

    In this work we present an introduction of the electrophoretic process followed by a detailed experimental treatment of the technique used in the determination and optimization of the ζ-potential, mainly as a function of the electrolyte concentration, in a high purity boron electrophoretics deposition on aluminium substrates used as electrodes in neutron detectors. (author)

  9. 成像毛细管等电聚焦电泳分析糖蛋白类生物技术药物%Analysis of glycoproteins by imaging capillary isoelectric focusing electrophoresis

    Institute of Scientific and Technical Information of China (English)

    王丽; 周勇; 王军志

    2012-01-01

    Objective To develop an imaging capillary isoelectric focusing electrophoresis method for analysis of isomer and isoelectric point of glycoproteins. Methods Three glycoproteins, i.e. recombinant human PEGlysated erythropoietin (PEG-EPO), re-combinant human TNK mutant of tissue type plasminogen activator (rhTNF-tPA) and humanized monoclonal antibody (McAb) A were analyzed for isomers and isoelectric points by imaging capillary isoelectric focusing electrophoresis. Results The isoelectric points and isomers of PEG-EPO, rhTNF-tPA and humanized McAb A were effectively analyzed by the developed imaging capillary isoelectric focusing electrophoresis method. The method was reliable, rapid, and showed high resolution and reproducibility. Conclusion Imaging capillary isoelectric focusing electrophoresis method may be used for analysis of isomer and electric point of glycoproteins, which provides en effective tool for ensuring the stability of production procedure and quality control of glycoproteins.%目的 建立成像毛细管等电聚焦电泳分析糖白蛋类生物技术药物的异构体和等电点的方法.方法 应用优化的成像毛细管等电聚焦电泳技术,对3种糖蛋白类生物技术药物即聚乙二醇化重组人促红素(PEGlysated erythropoietin,PEG-EPO)、重组人组织型纤溶酶原激活剂TNK突变体(Recombinant human TNK mutant of tissue type plasminogen activator,rhTNK-tPA)和全人源化单抗A的异构体和等电点进行分析.结果 采用优化的成像毛细管等电聚焦电泳技术,可较好地分析PEG-EPO、rhTNK-tPA和全人源化单抗A的等电点和异构体,该方法可靠、快速,具有较好的分离度和重现性.结论 成像毛细管等电聚焦电泳技术可用于分析糖蛋白类生物技术药物的异构体和等电点,为保证糖蛋白类生物技术药物生产工艺的稳定性及质量控制提供了有效手段.

  10. Capillary-scale polarimetry for flowing streams.

    Science.gov (United States)

    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

  11. Automated dual capillary electrophoresis system with hydrodynamic injection for the concurrent determination of cations and anions

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Thi Thanh Thuy; Mai, Thanh Duc [University of Basel, Department of Chemistry, Spitalstrasse 51, Basel 4056 (Switzerland); Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Nguyen, Thanh Dam [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Sáiz, Jorge [Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering – University of Alcalá, Ctra. Madrid-Barcelona km 33.6, Alcalá de Henares, Madrid 28871 (Spain); Pham, Hung Viet, E-mail: phamhungviet@hus.edu.vn [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Hauser, Peter C., E-mail: Peter.Hauser@unibas.ch [University of Basel, Department of Chemistry, Spitalstrasse 51, Basel 4056 (Switzerland)

    2014-09-02

    Highlights: • Concurrent determination of cations and anions was carried out by electrophoretic separation. • Optimized conditions for each class of analystes was possible by using separate capillaries. • Simultaneous hydrodynamic injection was carried out. • Pneumatic actuation was used for flushing and sample handling. • The denitrification of drinking water was successfully demonstrated. - Abstract: The capillary electrophoresis instrument developed for the concurrent determination of cations and anions features two separate capillaries and individual detectors to allow independent optimization for each group of ions. The capillaries are joined in a common injector block. The sample is drawn into the injector with a small membrane pump and automated simultaneous injection into both capillaries is achieved by pressurization of the fluid with compressed air. Flushing of the injector and of the capillaries with the background electrolyte is also carried out automatically by the same means. The buffer consisted of 12 mM histidine and 2 mM 18-crown-6 adjusted to pH 4 with acetic acid and was suitable for the contactless conductivity detection employed. The system was optimized for the determination of cationic NH{sub 4}{sup +} and anionic NO{sub 3}{sup −} and NO{sub 2}{sup −}, and linear calibration curves from about 20 μM up to about 1.5 mM were obtained for these ions. In a test run over 8 h, the reproducibility for the peak areas was within ±7%. For demonstration, the instrument was successfully applied to the concurrent monitoring of the concentrations of the three ions during the biological removal of ammonium from contaminated groundwater in a sequencing batch reactor, where NO{sub 3}{sup −} and NO{sub 2}{sup −} are formed as intermediate products.

  12. A Fractal Model for Capillary Pressure of Porous Media

    Directory of Open Access Journals (Sweden)

    Boqi Xiao

    2013-06-01

    Full Text Available Capillary pressure is a basic parameter in the study of the behavior of porous media containing two or more immiscible fluid phases. In this study, the capillary pressure of porous media is predicted based on based on fractal property of pore in porous media. The formula of calculating the capillary pressure of porous media is given. The capillary pressure of porous media is expressed as a function of porosity, fractal dimension of pore and saturation. Based on the parametric effect analysis, we conclude that the capillary pressure of porous media is negatively correlated with the porosity and saturation. Besides, it is shown that the capillary pressure of unsaturated porous media decreases with the increase of saturation. No additional empirical constant is introduced. This model contains less empirical constants than the conventional correlations. The model predictions are compared with the existing experimental data and good agreement between the model predictions and experimental data is found. The validity of the present fractal model is thus verified.

  13. Measurements of an ion beam diameter extracted into air through a glass capillary

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Natsuko, E-mail: fujita.natsuko@jaea.go.jp [Graduate School of Humanities and Sciences, Nara Women’s University, Nara, 630 8506 (Japan); Yamaki, Atsuko [Graduate School of Humanities and Sciences, Nara Women’s University, Nara, 630 8506 (Japan); Ishii, Kunikazu; Ogawa, Hidemi [Department of Physics, Nara Women’s University, Nara, 630 8506 (Japan)

    2013-11-15

    To establish techniques for in-air materials analysis using a glass capillary, we studied the beam distribution extracted in air as a function of the distance between the exit of the capillary and the target. We measured three-dimensional intensity distributions of the extracted beams, and compared the observed results with the model calculation. The comparison showed that the glass capillary technique is designed to reduce a divergence of the beam extracted into the air by a beam-focusing effect.

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

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

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

    OpenAIRE

    Tavares, Marina F. M.

    1997-01-01

    Since its inception in the 80's, capillary electrophoresis has matured into a well established technique for the separation and analysis of complex samples. One of its strongest aspects is the ability to handle materials from a diversity of chemical classes, ranging from few to millions of Daltons. This is only possible because several modes of electrophoresis can be performed in a single capillary format. In this work, relevant aspects of capillary zone electrophoresis in its three modes (fr...

  16. Electrophoretic Capture of a DNA Chain into a Nanopore

    CERN Document Server

    Rowghanian, Payam

    2013-01-01

    Based on our formulation of the DNA electrophoresis near a pore [P. Rowghanian and A. Y. Grosberg, Phys. Rev. E 87, 042723 (2013)], we address the electrophoretic DNA capture into a nanopore as a steady-state process of particle absorption to a sink placed on top of an energy barrier. Reproducing the previously observed diffusion-limited and barrier-limited regimes as two different limits of the particle absorption process and matching the data, our model suggests a slower growth of the capture rate with the DNA length for very large DNA molecules than the previous model, motivating more experiments beyond the current range of electric field and DNA length. At moderately weak electric fields, our model predicts a different effect, stating that the DNA length dependence of the capture rate first disappears as the field is reduced and eventually reverses to a decreasing trend with $N$.

  17. Electrophoretic Deposition of Carbon Nitride Layers for Photoelectrochemical Applications.

    Science.gov (United States)

    Xu, Jingsan; Shalom, Menny

    2016-05-25

    Electrophoretic deposition (EPD) is used for the growth of carbon nitride (C3N4) layers on conductive substrates. EPD is fast, environmentally friendly, and allows the deposition of negatively charged C3N4 with different compositions and chemical properties. In this method, C3N4 can be deposited on various conductive substrates ranging from conductive glass and carbon paper to nickel foam possessing complex 3D geometries. The high flexibility of this approach enables us to readily tune the photophysical and photoelectronic properties of the C3N4 electrodes. The advantage of this method was further illustrated by the tailored construction of a heterostructure between two complementary C3N4, with marked photoelectrochemical activity.

  18. Electrophoretic assay of specific estrogen receptors: a contribution to methodology.

    Science.gov (United States)

    van Netten, J P; Algard, F T; Montessori, G; Weare, B

    1977-11-01

    Experimental evidence is presented that supports the use of the cold agar-gel electrophoretic method for the clinical quantitation of specific estrogen-binding protein present in some human mammary carcinomas. It is necessary to dilute tumor extracts to avoid interference by serum-borne, non-relevant hormone-binding proteins such as albumin, which migrates to the same anodal region as does the binding protein. Dilution to 2.5 mg or less of total protein per milliliter circumvents such interference while still permitting reliable quantitation of the binding protein. Seventy-two mammary carcinomas were compared for binding-protein content by both the cold agar-gel electrophoresis and a single-point dextran-coated charcoal assay. The correlation coefficient (0.96) indicated excellent agreement between results by the two methods. In addition results are presented which indicate that the preparation of tumor extracts for electrophoresis does not require the use of an ultracentrifuge. PMID:912871

  19. Electrophoretic analyses of proteins transported to the rat posterior pituitary

    International Nuclear Information System (INIS)

    [35S] cysteine, [3H] methionine, or [3H] fucose were injected into the supraoptic nuclei (SON) of rats, and the labelled proteins that were transported to and accumulated in the posterior pituitary 24 h post-injection were analyzed electrophoretically. The transported, labelled proteins which were soluble in 0.1 M-HCl were primarily of low molecular weight (about 12,000 on SDS gels). However, the selectivity of labelling of these proteins by the three different labelled precursors could be revealed by isoelectric focusing. The 0.1 M-HCl insoluble labelled proteins, presumably reflecting membrane proteins transported from the SON to the pituitary, were more diverse and generally of higher molecular weight (> 43,000 on SDS gels). (author)

  20. Coating of calcium phosphate on biometallic materials by electrophoretic deposition

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    Although biometallic materials have been used as bone implant materials for a long time, they are still detected as foreign bodies by human immune system. Calcium phosphate coating, especially hydroxyapatite(HA)coating attracts special attention due to its good biocompatibility. Being one of the effective methods used to deposit HA coating onto the metallic implant, the electrophoretic deposition(EPD) was reviewed in detail, including the process of EPD, the advantages and disadvantages, the important processing factors and the microstructure and mechanical properties of the coating. Research results on the processing and the coating show potential application of EPD process to the biomedical materials surface modification. In addition, the nanoparticulate HA coating as a new trend in HA coating was also introduced.

  1. Capillary Array Waveguide Amplified Fluorescence Detector for mHealth.

    Science.gov (United States)

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2013-09-01

    array can potentially be used for sensitive analysis of multiple fluorescent detection assays simultaneously. The simple phone based capillary array approach presented in this paper is capable of amplifying weak fluorescent signals thereby improving the sensitivity of optical detectors based on mobile phones. This may allow sensitive biological assays to be measured with low sensitivity detectors and may make mHealth practical for many diagnostics applications, especially in resource-poor and global health settings.

  2. Electrophoretic deposition of ultrasonicated and functionalized nanomaterials for multifunctional composites

    Science.gov (United States)

    An, Qi

    Recent advances in the synthesis and characterization of nanostructured composite materials have enabled a broad range of opportunities for engineering the properties of polymer-matrix materials. Carbon nanotubes (CNTs) are known to have exceptional mechanical, electrical and thermal properties. Because of their small size, CNTs can occupy regions between traditional micro-scale reinforcements and create a hierarchical micro/nano structure spanning several orders of magnitude. Since CNTs possess critical reinforcement dimensions below 100 nm, new opportunities exist for tailoring the fiber/matrix interphase regions and ultimately the mechanical and electrical performance of advanced fiber-composites with minimal impact on the fiber-dominated properties. This growing interest in nanoscale hybridization with conventional fiber reinforcement has highlighted the need to develop new processing techniques for successful CNT integration. In this work, a novel and industrially scalable approach for producing multi-scale hybrid carbon nanotube/fiber composites using an electrophoretic deposition (EPD) technique has been studied as an alternative to in situ chemical vapor deposition growth (CVD). EPD is a widely used industrial coating process employed in areas ranging from automotive to electronics production. The method has a number of benefits which include low energy use and the ability to homogenously coat complex shapes with well adhered films of controlled thickness and density. A stable aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) was produced using a novel ozonolysis and ultrasonication (USO) technique that results in dispersion and functionalization in a single step. Networks of CNTs span between adjacent fibers and the resulting composites exhibit significant increases in electrical conductivity and considerable improvements in the interlaminar shear strength and fracture toughness. In order to better understand the underlying mechanisms behind the

  3. The potential of SNP-based PCR-RFLP capillary electrophoresis analysis to authenticate and detect admixtures of Mediterranean olive oils.

    Science.gov (United States)

    Bazakos, Christos; Khanfir, Emna; Aoun, Mariem; Spano, Thodhoraq; Zein, Zeina El; Chalak, Lamis; Riachy, Milad El; Abou-Sleymane, Gretta; Ali, Sihem Ben; Grati Kammoun, Naziha; Kalaitzis, Panagiotis

    2016-07-01

    Authentication and traceability of extra virgin olive oil is a challenging research task due to the complexity of fraudulent practices. In this context, the monovarietal olive oils of Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) require new tests and cutting edge analytical technologies to detect mislabeling and misleading origin. Toward this direction, DNA-based technologies could serve as a complementary to the analytical techniques assay. Single nucleotide polymorphisms are ideal molecular markers since they require short PCR analytical targets which are a prerequisite for forensic applications in olive oil sector. In the present study, a small number of polymorphic SNPs were used with an SNP-based PCR-RFLP capillary electrophoresis platform to discriminate six out of 13 monovarietal olive oils of Mediterranean origin from three different countries, Greece, Tunisia, and Lebanon. Moreover, the high sensitivity of capillary electrophoresis in combination with the DNA extraction protocol lowered the limit of detection to 10% in an admixture of Tsounati in a Koroneiki olive oil matrix. PMID:26864388

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ziqiang

    1999-12-10

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

  5. Simultaneous determination of nanomole amounts of sulphur dioxide and hydrogen sulphide by flow injection analysis with on-line preconcentration by means of capillary denuder tubes.

    Science.gov (United States)

    Achilli, Marco; Gács, Istvan

    2002-01-01

    A simple and rapid method for trace determination of SO2 and H2S in gaseous samples by using a flow injection system with on line preconcentration on capillary denuder is described. The gaseous samples are led through a 0.4 M sulphamic acid solution, retaining nitrogen dioxide, ammonia and hydrogen chloride. The sulphur dioxide is collected from the carrier gas stream (250 cm3 min-1) as sulphuric acid in a capillary denuder tube coated with a thin layer of 0.01-0.03 M hydrogen peroxide solution of 0.05 mM sulphuric acid; hydrogen sulphide passes into a second tube coated with 0.075 mM sodium sulphide solution of 0.1 M aqueous sodium hydroxide. The films containing the sulphuric acid and the sodium sulphide, respectively, are eluted with the corresponding circulating absorbent streams and pass through the detectors. Sulphuric acid is detected by conductimetry and sulphide is determined spectrophotometrically at 230 nm. If nanoequivalent amounts of H2S are present in the sample containing a large concentration of SO2 (SO2/H2S concentration ratio > 20), the sulphur dioxide is filtered out of the sample gas stream by solid sodium hydrogen carbonate. A limit of detection of 3.5 micrograms m-3 is obtained.

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

    Science.gov (United States)

    Gong, X; Yeung, E S

    1999-11-01

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

  7. 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

    Science.gov (United States)

    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.

  8. Analysis of Dimethyl Ether in Liquefied Petroleum Gases by Capillary Gas Chromatography%毛细管气相色谱法分析液化石油气中二甲醚含量

    Institute of Scientific and Technical Information of China (English)

    吕文姬

    2012-01-01

    A method was developed for the detection of the dimethyl ether in the liquefied petroleum gas by constant temperature water bath gasification sampling and capillary gas chromatography with TCD detector and PLOT/Q(30m×0.53mm×40μm)capillary column.Helium was used as carrier gas and area normalization method was applied to calculate the content of the dimethyl ether.The result showed that the method was easy to operate and practical with good accuracy and repeatability,and can be used for the analysis of the dimethyl ether in liquefied petroleum.%通过恒温水浴完全气化样品,建立了用毛细管气相色谱法测定液化石油气中二甲醚含量的方法。采用PLOT/Q(30 m×0.53 mm×40μm)毛细管柱,以热导池检测器检测,氦气为载气,以面积校正归一化法计算二甲醚含量。结果表明,该方法操作简单,实用性强,重复性好,可以用于液化石油气中二甲醚含量的分析。

  9. Numerical Modeling of the Performance of R22 and R290 in Adiabatic Capillary Tubes Considering Metastable Two-Phase Region--Flow Characteristics and Parametric Analysis of R22 and R290

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guobing; ZHANG Yufeng; HAO Hong

    2005-01-01

    Characteristics of R22 and its new alternative refrigerant R290 flowing through adiabatic capillary tubes are investigated based on the homogeneous model.Extensive flow variables along tube length such as pressure, temperature, viscosity, velocity, Reynolds number, friction factor and vapor quality etc are compared between the two fluids under the same operating condition. Two cases are considered, namely, either the same tube length or the same mass flow rate as inlet condition. The results show that the mass flow rate in the capillary tube of R290 is 40% lower than that of R22 due to the differences of physical properties between the two fluids. Further, a parametric analysis is performed and it appears that effects of geometric and thermodynamic parameters on mass flow rate of R290 are weaker than that of R22. When the condensing temperature is increased from 40 ℃ to 50 ℃, the mass flow rate for R22 is increased by 16%, while the increasing rate for R290 is 13%.

  10. Analysis of Calcium Propionate in Food by Capillary Gas Chromatography%毛细管气相色谱法测定食品中丙酸钙的含量

    Institute of Scientific and Technical Information of China (English)

    颜晓丽

    2012-01-01

    A method to analyze calcium propionate in food was developed by capillary gas chromatography (CGC), using free fatty acid phase (FFAP) capillary column and a flame ionization detector (FID). While external standard method was used for quantitative analysis and had a good linearity in the concentration range of 5txg/mL -250μg/mL. The average recovery was 93.2%, the relative standard deviation was 1.5% (n =6) and the limit detection was 2.8μg/mL.%建立了毛细管气相色谱法测定食品中丙酸钙含量的分析方法。该方法采用强极性FFAP石英毛细管柱和氢火焰检测器测定,外标法定量,丙酸含量在5~250μg/mL浓度范围内具有良好的线性关系(R=0.9997),加标回收率为93.2%,相对标准偏差为1.5%,标准曲线线性相关系数为0.9997,1μL进样最低检出限为2.8μg/mL。

  11. Impacts on oil recovery from capillary pressure and capillary heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Bognoe, Thomas

    2008-07-01

    The main conclusions drawn from this thesis are; 7 scientific papers are published on a broad variety of subjects, and describes in detail the experiments and research treated in this thesis. Scientific research has been performed, investigating the subjects of capillary pressure and capillary heterogeneities from different angles. This thesis discusses the findings in this study and aims to illustrate the benefits of the results obtained for further development of other experiments, and/or even the industrial benefits in field development. The methods for wettability alteration have developed throughout the work. From producing heterogeneous wettability alterations, the methods have improved to giving both radial and lateral uniform wettability alterations, which also remains unaltered throughout the duration of the experimental work. The alteration of wettability is dependent on initial water saturation, flow rate, aging time and crude oil composition. Capillary pressure and relative permeability curves have been measured for core plugs at different wettabilities using conventional centrifuge methods. The trends observed are mostly consistent with theory. The production mechanisms of strongly and moderately water wet chalk has been investigated. At strongly water wet conditions in fractured chalk; the flow is governed by capillary forces, showing strong impact from the fractures. At moderately water wet conditions, the impact of the fractures are absent, and a dispersed water front is observed during the displacement. The oil recovery is about the same, at the two wettabilities. Fracture crossing mechanisms at the same wettability conditions have been mapped. And the observations are consistent with those of the water floods. During strongly water wet displacement, the fracture crossing is occurring once the inlet core has reached endpoint of spontaneous imbibition. At moderately water wet conditions the fracture crossing is less abrupt, and creation of wetting

  12. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    Szumski, Michał; Buszewski, Bogusław

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

  13. Analysis of phenolic compounds in Spanish Albrariño and Portuguese Alvarinho and Loureiro wines by capillary zone electrophoresis and high-performance liquid chromatography.

    Science.gov (United States)

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

    2001-05-01

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

  14. Analysis of trace amounts of carbon dioxide, oxygen and carbon monoxide in nitrogen using dual capillary columns and a pulsed discharge helium ionisation detector.

    Science.gov (United States)

    Janse van Rensburg, M; Botha, A; Rohwer, E

    2007-10-01

    Gas mixtures of trace amounts of carbon dioxide (CO(2)), dioxygen (O(2)), and carbon monoxide (CO) in dinitrogen (N(2)) were separated and quantified using parallel dual capillary columns and pulsed discharge helium ionisation detection (PDHID). The detection limits (9 x 10(-9) mol mol(-1) for CO(2), 7 x 10(-9) mol mol(-1) for O(2) and 37 x 10(-9) mol mol(-1) for CO) were lower than those reported previously for similar methods. Uncertainties were calculated and results were validated by comparison of the CO and CO(2) results with those obtained using conventional methods. The method was also used to analyse nitrogen, carbon dioxide and carbon monoxide in oxygen. PMID:17765907

  15. Simultaneous confirmatory analysis of different transgenic maize (zea mays) lines using multiplex polymerase chain reaction-restriction analysis and capillary gel electrophoresis with laser induced fluorescence detection.

    Science.gov (United States)

    García-Cañas, Virginia; Cifuentes, Alejandro

    2008-09-24

    A novel analytical procedure based on the combination of multiplex PCR, restriction analysis, and CGE-LIF to unambiguosly and simultaneously confirm the presence of multiple lines of genetically modified corn is proposed. This methodology is based on the amplification of event-specific DNA regions by multiplex PCR using 6-FAM-labeled primers. Subsequently, PCR products are digested by a mixture containing specific restriction endonucleases. Thus, restriction endonucleases selectively recognize DNA target sequences contained in the PCR products and cleave the double-stranded DNA at a given cleavage site. Next, the restriction digest is analyzed by CGE-LIF corroborating the length of the expected restriction fragments, confirming (or not) the existence of GMOs. For accurate size determination of the DNA fragments by CGE-LIF a special standard DNA mixture was produced in this laboratory for calibration. The suitability of this mixture for size determination of labeled DNA fragments is also demonstrated. The usefulness of the proposed methodology is demonstrated through the simultaneous detection and confirmatory analysis of samples containing 0.5% of GA21 and MON863 maize plus an endogenous gene of maize as control.

  16. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter; Hassager, Ole

    1998-01-01

    The capillary thinning of a polymeric filament is analysed experimentally as well as by means of numerical simulation. The experimental procedure is as follows. Initially a liquid sample is kept between two cylindrical plates. Then the bottom plate is lowered under gravity to yield a given strain...

  17. Capillary Rise in a Wedge

    Science.gov (United States)

    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…

  18. Development and characterization of a novel semiautomated arrangement for electrochemically assisted injection in combination with capillary electrophoresis time-of-flight mass spectrometry.

    Science.gov (United States)

    Palatzky, Peter; Matysik, Frank-Michael

    2012-09-01

    Electrochemically assisted injection (EAI) is an attractive injection concept for CE that enables the separation of neutral analytes via electrochemical generation of charged species during the injection process. A new semiautomated EAI configuration was developed and applied in conjunction with CE-MS (EAI-CE-MS). The EAI cell arrangement consists of an integrated buffer reservoir for CE separations and a compartment holding screen-printed electrodes. A drop of sample solution (50 μL) was sufficient to cover the three-electrode structures. A piezo motor provided a fast and precise capillary positioning over the screen-printed electrode assembly. Using ferrocene methanol as a model system, the EAI arrangement was characterized regarding coulometric efficiency, precision, and sensitivity of electrospray ionization-time-of-flight-MS. The formation of the cationic oxidation product of ferrocene methanol enhanced the sensitivity of CE-MS determination by two orders of magnitude and the electrochemically formed product showed a migration time corresponding to its individual electrophoretic mobility. Preliminary studies of EAI-CE-MS in the field of the analysis of nitroaromatic compounds were carried out. The formation of corresponding hydroxylamines and amines paved the way for selective and sensitive CE-MS determinations without the need of adding surfactants to the electrophoresis buffer.

  19. AC electrophoretic deposition of organic-inorganic composite coatings.

    Science.gov (United States)

    Yoshioka, T; Chávez-Valdez, A; Roether, J A; Schubert, D W; Boccaccini, A R

    2013-02-15

    Alternating current electrophoretic deposition (AC-EPD) of polyacrylic acid (PAA)-titanium oxide (TiO(2)) nanoparticle composites on stainless steel electrodes was investigated in basic aqueous solution. AC square wave with duty cycle of 80% was applied at a frequency of 1 kHz. FTIR-ATR spectra showed that both AC and direct current (DC) EPD successfully deposited PAA-TiO(2) composites. The deposition rate using AC-EPD was lower than that obtained in direct current DC-EPD. However, the microstructure and surface morphology of the deposited composite coatings were different depending on the type of electric field applied. AC-EPD applied for not more than 5 min led to smooth films without bubble formation, while DC-EPD for 1 min or more showed deposits with microstructural defects possibly as result of water electrolysis. AC-EPD was thus for the first time demonstrated to be a suitable technique to deposit organic-inorganic composite coatings from aqueous suspensions, showing that applying a square wave and frequency of 1 kHz leads to uniform PAA-TiO(2) composite coatings on conductive materials.

  20. Fabrication of Electrophoretic Display Driven by Membrane Switch Array

    Science.gov (United States)

    Senda, Kazuo; Usui, Hiroaki

    2010-04-01

    Electrophoretic devices (EPDs) and organic light-emitting diodes (OLEDs) have potential application in a large-area flexible displays, such as digital signage. For this purpose, a new backplane is capable of driving a large unit is required instead of thin-film transistors. In this paper we describe the fabrication of a membrane switch array suitable for driving large-scale flat-panel displays. An array of membrane switches was prepared using flexible printed circuit (FPC) technology of polyimide films, by combining low-temperature processes of lamination and copper electroplating methods. An array of 256 matrix switches with a pixel size of 7 mm2 was prepared to drive the EPD front panel. The switches were driven at a voltage of about 40 V and a frequency of 10 Hz. The operation characteristics agreed well with the result of the theoretical calculation. The calculation also suggested that driving voltage can be lowered by increasing pixel size. The contact resistance of the membrane switch was as low as 0.2 Ω, which implies the wide applicability of this device for driving a variety of elements.

  1. Electrophoretically deposited nano-structured polyaniline film for glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Dhand, Chetna [Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics and Engineering Division, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Department of Chemistry, University of Delhi, Delhi 110007 (India); Sumana, G. [Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics and Engineering Division, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Datta, Monika [Department of Chemistry, University of Delhi, Delhi 110007 (India); Malhotra, B.D., E-mail: bansi.malhotra@gmail.co [Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics and Engineering Division, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Centre for NanoBioEngineering and Spintronics, Chungnam National University, Daejeon, 305-764 (Korea, Republic of)

    2010-11-30

    Electrophoretically deposited nano-structured polyaniline (NS-PANI) film has been utilized for fabrication of glucose biosensor by covalent immobilization of glucose oxidase (GOx) using N-ethyl-N-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide chemistry. This GOx/NS-PANI/ITO bioelectrode has been characterized using scanning electron microscopy, FT-IR, UV-Visible spectroscopy and differential pulse voltammetry (DPV) techniques. The response studies carried out on GOx/NS-PANI/ITO bioelectrode using DPV and photometric studies reveal linearity up to 400 mgdL{sup -1} with sensitivity as 1.05 x 10{sup -4} mA mg{sup -1} dL and 3.887 x 10{sup -5} Abs mg{sup -1} dL, respectively. The lower value of Michaelis-Menten constant obtained for immobilized GOx (2.1 mM) compared with that of free GOx (5.85 mM) suggests high affinity of enzyme to this matrix.

  2. Interfacial bond strength of electrophoretically deposited hydroxyapatite coatings on metals.

    Science.gov (United States)

    Wei, M; Ruys, A J; Swain, M V; Kim, S H; Milthorpe, B K; Sorrell, C C

    1999-07-01

    Hydroxyapatite (HAp) coatings were deposited onto substrates of metal biomaterials (Ti, Ti6Al4V, and 316L stainless steel) by electrophoretic deposition (EPD). Only ultra-high surface area HAp powder, prepared by the metathesis method 10Ca(NO3)2 + 6(NH4)2HPO4 + 8NH4OH), could produce dense coatings when sintered at 875-1000degreesC. Single EPD coatings cracked during sintering owing to the 15-18% sintering shrinkage, but the HAp did not decompose. The use of dual coatings (coat, sinter, coat, sinter) resolved the cracking problem. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) inspection revealed that the second coating filled in the "valleys" in the cracks of the first coating. The interfacial shear strength of the dual coatings was found, by ASTM F1044-87, to be approximately 12 MPa on a titanium substrate and approximately 22 MPa on 316L stainless steel, comparing quite favorably with the 34 MPa benchmark (the shear strength of bovine cortical bone was found to be 34 MPa). Stainless steel gave the better result since -316L (20.5 microm mK(-1)) > alpha-HAp (approximately 14 microm mK(-1)), resulting in residual compressive stresses in the coating, whereas alpha-titanium (approximately 10.3 microm mK(-1)) < alpha-HAp, resulting in residual tensile stresses in the coating. PMID:15348125

  3. Solubilization and electrophoretic characterization of select edible nut seed proteins.

    Science.gov (United States)

    Sathe, Shridhar K; Venkatachalam, Mahesh; Sharma, Girdhari M; Kshirsagar, Harshal H; Teuber, Suzanne S; Roux, Kenneth H

    2009-09-01

    The solubility of almond, Brazil nut, cashew nut, hazelnut, macadamia, pecan, pine nut, pistachio, walnut, and peanut proteins in several aqueous solvents was qualitatively and quantitatively assessed. In addition, the effects of extraction time and ionic strength on protein solubility were also investigated. Electrophoresis and protein determination (Lowry, Bradford, and micro-Kjeldahl) methods were used for qualitative and quantitative assessment of proteins, respectively. Depending on the seed, buffer type and ionic strength significantly affected protein solubility. The results suggest that buffered sodium borate (BSB; 0.1 M H(3)BO(3), 0.025 M Na(2)B(4)O(7), 0.075 M NaCl, pH 8.45) optimally solubilizes nut seed proteins. Qualitative differences in seed protein electrophoretic profiles were revealed. For a specific seed type, these differences were dependent on the solvent(s) used to solubilize the seed proteins. SDS-PAGE results suggest the polypeptide molecular mass range for the tree nut seed proteins to be 3-100 kDa. The results of native IEF suggested that the proteins were mainly acidic, with a pI range from >4.5 to <7.0. Western immunoblotting experiments indicated that rabbit polyclonal antibodies recognized substantially the same polypeptides as those recognized by the corresponding pooled patient sera IgE. PMID:19655801

  4. Electrophoretic assembly of organic molecules and composites for electrochemical supercapacitors.

    Science.gov (United States)

    Su, Y; Zhitomirsky, I

    2013-02-15

    Electrophoretic deposition (EPD) method has been developed for the fabrication of 1-pyrenebutyric acid (PBH) films from aqueous solutions. The films can be deposited at constant voltage or potentiodynamic conditions. The method allowed the formation of 0.1-2 μm thick films, containing needle-shape PBH particles. The deposition mechanism involved the electrophoresis, pH decrease at the anode surface, charge neutralization and formation of insoluble PBH films. The film morphology and shape of the PBH particles are controlled by the π-π stacking mechanism of the polyaromatic PBH molecules. The important finding was the possibility of controlled EPD of multiwalled carbon nanotubes (MWCNTs) using PBH as a charging, dispersing and film forming agent. It was found that at low voltages or low PBH concentrations the deposits contained mainly MWCNT. The increase in the deposition voltage or/and PBH concentration resulted in co-deposition of MWCNT and needle-shape PBH particles. The new approach to the deposition of MWCNT was used for the fabrication of composite MnO(2)-MWCNT films for electrodes of electrochemical supercapacitors, which showed a specific capacitance of 250 F g(-1). The EPD method developed in this investigation paves the way for the deposition of other small organic molecules and composites and their applications in new materials and devices, utilizing functional properties of the organic molecules, CNT, and other advanced materials. PMID:23141761

  5. Integrated Microfluidic Isolation of Aptamers Using Electrophoretic Oligonucleotide Manipulation

    Science.gov (United States)

    Kim, Jinho; Olsen, Timothy R.; Zhu, Jing; Hilton, John P.; Yang, Kyung-Ae; Pei, Renjun; Stojanovic, Milan N.; Lin, Qiao

    2016-05-01

    We present a microfluidic approach to integrated isolation of DNA aptamers via systematic evolution of ligands by exponential enrichment (SELEX). The approach employs a microbead-based protocol for the processes of affinity selection and amplification of target-binding oligonucleotides, and an electrophoretic DNA manipulation scheme for the coupling of these processes, which are required to occur in different buffers. This achieves the full microfluidic integration of SELEX, thereby enabling highly efficient isolation of aptamers in drastically reduced times and with minimized consumption of biological material. The approach as such also offers broad target applicability by allowing selection of aptamers with respect to targets that are either surface-immobilized or solution-borne, potentially allowing aptamers to be developed as readily available affinity reagents for a wide range of targets. We demonstrate the utility of this approach on two different procedures, respectively for isolating aptamers against a surface-immobilized protein (immunoglobulin E) and a solution-phase small molecule (bisboronic acid in the presence of glucose). In both cases aptamer candidates were isolated in three rounds of SELEX within a total process time of approximately 10 hours.

  6. An improved driving waveform reference grayscale of electrophoretic displays

    Science.gov (United States)

    Wang, Li; Yi, Zichuan; Peng, Bao; Zhou, Guofu

    2015-10-01

    Driving waveform is an important component for gray scale display on the electrophoretic display (EPD). In the traditional driving waveform, a white reference gray scale is formed before writing a new image. However, the reflectance value can not reach agreement in each gray scale transformation. In this paper, a new driving waveform, which has a short waiting time after the formation of reference gray scale, is proposed to improve the consistency of reference gray scale. Firstly, the property of the particles in the microcapsule is analyzed and the change of the EPD reflectance after the white reference gray scale formation is studied. Secondly, the reflectance change curve is fitted by using polynomial and the duration of the waiting time is determined. Thirdly, a set of the new driving waveform is designed by using the rule of DC balance and some real E-ink commercial EPDs are used to test the performance. Experimental results show that the effect of the new driving waveform has a better performance than traditional waveforms.

  7. Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography.

    Science.gov (United States)

    Kazarian, Artaches A; Sanz Rodriguez, Estrella; Deverell, Jeremy A; McCord, James; Muddiman, David C; Paull, Brett

    2016-01-28

    Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L(-1) levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min(-1), and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L(-1) for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%.

  8. PCR-SSCP analysis of p16 gene mutation by capillary electrophoresis with laser-induced fluorescence detector%毛细管电泳PCR-SSCP分析p16基因突变

    Institute of Scientific and Technical Information of China (English)

    吴逸明; 张振中; 史香林

    2000-01-01

    @@ Lung cancer is one of the most common cancers in the world. Some genetic alterations such as p53 gene and ras gene mutations, have been identified in this disease. Recently, a putative tumor suppressor gene, the p16/CDKN2/MTS1 gene containing 3 extrons and 2 introns, located in the chromosome p21 region, was cloned independently by three research groups. Traditionally, gene mutation analysis was performed by slab polyacrylamide gel electrophoresis. However, this method is laborious, time-consuming, low sensitivity and harmful to human health. Capillary electrophoresis (CE) with the characteristics of rapidity and high performance has numerous advantages over conventional slab polyacrylamide gel electrophoresis. An important advantage of CE is that the commercially available system is automation.

  9. DNA Sequencing Using capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. A plasmid containing the human metallothionein II gene can function as an antibody-assisted electrophoretic biosensor for heavy metals.

    Science.gov (United States)

    Wooten, Dennis C; Starr, Clarise R; Lyon, Wanda J

    2016-01-01

    Different forms of heavy metals affect biochemical systems in characteristic ways that cannot be detected with typical metal analysis methods like atomic absorption spectrometry. Further, using living systems to analyze interaction of heavy metals with biochemical systems can be laborious and unreliable. To generate a reliable easy-to-use biologically-based biosensor system, the entire human metallothionein-II (MT-II) gene was incorporated into a plasmid (pUC57-MT) easily replicated in Escherichia coli. In this system, a commercial polyclonal antibody raised against human metal-responsive transcription factor-1 protein (MTF-1 protein) could modify the electrophoretic migration patterns (i.e. cause specific decreases in agarose gel electrophoretic mobility) of the plasmid in the presence or absence of heavy metals other than zinc (Zn). In the study here, heavy metals, MTF-1 protein, and polyclonal anti-MTF-1 antibody were used to assess pUC57-MT plasmid antibody-assisted electrophoretic mobility. Anti-MTF-1 antibody bound both MTF-1 protein and pUC57-MT plasmid in a non-competitive fashion such that it could be used to differentiate specific heavy metal binding. The results showed that antibody-inhibited plasmid migration was heavy metal level-dependent. Zinc caused a unique mobility shift pattern opposite to that of other metals tested, i.e. Zn blocked the antibody ability to inhibit plasmid migration, despite a greatly increased affinity for DNA by the antibody when Zn was present. The Zn effect was reversed/modified by adding MTF-1 protein. Additionally, antibody inhibition of plasmid mobility was resistant to heat pre-treatment and trypsinization, indicating absence of residual DNA extraction-resistant bacterial DNA binding proteins. DNA binding by anti-DNA antibodies may be commonly enhanced by xenobiotic heavy metals and elevated levels of Zn, thus making them potentially effective tools for assessment of heavy metal bioavailability in aqueous solutions and

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  12. Electrophoretic mobilities of cultured human embryonic kidney cells in various buffers

    Science.gov (United States)

    1985-01-01

    Data on the electrophoretic mobility distributions of cells in the new D-1 buffer and the interlaboratory standardization of urokinase assay methods are presented. A table of cell strains and recent data on cell dispersal methods are also included. It was decided that glycerol in A-1 electrophoretic mobility data on cultured human embryonic kidney cells subjected to electrophoresis in this buffer. The buffer composition is presented.

  13. Mapping molecular adhesion sites inside SMIL coated capillaries using atomic force microscopy recognition imaging.

    Science.gov (United States)

    Leitner, Michael; Stock, Lorenz G; Traxler, Lukas; Leclercq, Laurent; Bonazza, Klaus; Friedbacher, Gernot; Cottet, Hervé; Stutz, Hanno; Ebner, Andreas

    2016-08-01

    Capillary zone electrophoresis (CZE) is a powerful analytical technique for fast and efficient separation of different analytes ranging from small inorganic ions to large proteins. However electrophoretic resolution significantly depends on the coating of the inner capillary surface. High technical efforts like Successive Multiple Ionic Polymer Layer (SMIL) generation have been taken to develop stable coatings with switchable surface charges fulfilling the requirements needed for optimal separation. Although the performance can be easily proven in normalized test runs, characterization of the coating itself remains challenging. Atomic force microscopy (AFM) allows for topographical investigation of biological and analytical relevant surfaces with nanometer resolution and yields information about the surface roughness and homogeneity. Upgrading the scanning tip to a molecular biosensor by adhesive molecules (like partly inverted charged molecules) allows for performing topography and recognition imaging (TREC). As a result, simultaneously acquired sample topography and adhesion maps can be recorded. We optimized this technique for electrophoresis capillaries and investigated the charge distribution of differently composed and treated SMIL coatings. By using the positively charged protein avidin as a single molecule sensor, we compared these SMIL coatings with respect to negative charges, resulting in adhesion maps with nanometer resolution. The capability of TREC as a functional investigation technique at the nanoscale was successfully demonstrated. PMID:27265903

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

    Science.gov (United States)

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

    2015-10-16

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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2012-08-01

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

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

    Science.gov (United States)

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

    2012-12-01

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

  18. A capillary-driven micromixer: idea and fabrication

    International Nuclear Information System (INIS)

    Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis. (paper)

  19. A capillary-driven micromixer: idea and fabrication

    Science.gov (United States)

    Lee, Chun-Te; Lee, Chun-Che

    2012-10-01

    Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis.

  20. Validação em métodos cromatográficos e eletroforéticos Validation for chromatographic and electrophoretic methods

    Directory of Open Access Journals (Sweden)

    Marcelo Ribani

    2004-10-01

    Full Text Available The validation of an analytical method is fundamental to implementing a quality control system in any analytical laboratory. As the separation techniques, GC, HPLC and CE, are often the principal tools used in such determinations, procedure validation is a necessity. The objective of this review is to describe the main aspects of validation in chromatographic and electrophoretic analysis, showing, in a general way, the similarities and differences between the guidelines established by the different Brazilian and international regulatory agencies.

  1. Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air.

    Science.gov (United States)

    Coelho, Lúcia H G; Melchert, Wanessa R; Rocha, Flavio R; Rocha, Fábio R P; Gutz, Ivano G R

    2010-11-15

    The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the μg m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All

  2. Three-Dimensional Reconstruction of Erythrocyte in the Capillary

    CERN Document Server

    Fan, Yifang; Li, Zhiyu; Lin, Wentao; Wei, Yuan; Zhong, Xing; Newman, Tony; Lv, Changsheng; Fan, Yuzhou

    2013-01-01

    The dynamic analysis of erythrocyte deformability is used as an important means for early diagnosis of blood diseases and blood rheology. Yet no effective method is available in terms of three-dimensional reconstruction of erythrocytes in a capillary. In this study, ultrathin serial sections of skeletal muscle tissue are obtained from the ultramicrotome, the tomographic images of an erythrocyte in a capillary are captured by the transmission electron microscope, and then a method to position and restore is devised to demonstrate the physiological relationship between two adjacent tomographic images of an erythrocyte. Both the modeling and the physical verification reveal that this method is effective, which means that it can be used to make three-dimensional reconstruction of an erythrocyte in a capillary. An example of reconstructed deformation of erythrocyte based on the serial ultrathin sections is shown at the end of this paper.

  3. In-Line Desalting of Proteins from Buffer and Synthetic Urine Solution Prior to ESI-MS Analysis via a Capillary-Channeled Polymer Fiber Microcolumn

    Science.gov (United States)

    Burdette, Carolyn Q.; Marcus, R. Kenneth

    2013-06-01

    Presented here is a novel in-line solid phase extraction (SPE) method utilizing a capillary-channeled polymer (C-CP) fiber microcolumn prior to introduction to an electrospray ionization (ESI) source. The high permeability of the microcolumn allows for operation under syringe pump or HPLC driven flow, ultimately providing greater mass spectral clarity and accurate molecular weight determinations for different protein/buffer combinations. Studies presented here focus on the desalting of several target proteins from a standard phosphate buffered saline (PBS) matrix and a synthetic urine solution prior to ESI-MS determinations. In every case, responses for μM-level proteins in PBS improve from the situation of not permitting molecular weight determinations to values that are precise to better than ±10 Da, without internal standards, with relative improvements in the signal-to-background ratios (S/B) on the order of 3,000×. De-salting of a myoglobin-spiked (12 μM) synthetic urine results in equally-improved spectral quality.

  4. Fluorescence-based Multiplex PCR-Single Strand Conformation Polymorphism (SSCP) Analysis of 16S Ribosomal DNA Using Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    高鹏; 韩英; 许国旺; 赵春霞; 戴兵; 李萍; 王运铎; 温杰; 徐维家

    2004-01-01

    The rRNA genetic locus is found in all prokaryotic organisms, and is highly conservative, although its relatively stable variations are found frequently in different bacteria. The utility of this locus as a taxonomic and phylogenetic tool has been reported widely. This study, aimed at 16S rRNA gene ( 16S rDNA) and with the help of biomolecular methods, attempted to achieve the goal of rapid identification of common pathogens In this study, 333 clinical isolated pathogenic bacteria were collected。 Two pairs of primers were chosen and labeled with different fluorescent dyes and then used to amplify the genomic DNA extracted from bacteria. The PCR products were then detected by capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) . In order to pursue higher resolution and peak-separation effect, a high efficient separating medium, liner polyacrylamidedel (LPA), was put to use in this study. Finally, every bacteria colony generated distinct patterns from each other, which were easily to be used for identification.These results indicated that PCR-CE-SSCP was a rapid identification method for bacterial identification, with the aspects of high efficiency and high precision. Compared with traditional method, this technology is of great utility for clinical use especially for its high sensitivity.

  5. Analysis of nucleic acids by capillary ion-pair reversed-phase HPLC coupled to negative-ion electrospray ionization mass spectrometry.

    Science.gov (United States)

    Huber, C G; Krajete, A

    1999-09-01

    Ion-pair reversed-phase high-performance liquid chromatography was successfully coupled to negative-ion electrospray ionization mass spectrometry by using 60 × 0.20 mm i.d. capillary columns packed with 2.3-μm micropellicular, octadecylated poly(styrene/divinylbenzene) particles as stationary phase and gradients of acetonitrile in 50 mM aqueous triethylammonium bicarbonate as mobile phase. Systematic variation of the eluent composition, such as concentration of ion-pair reagent, anion in the ion-pair reagent, solution pH, and acetonitrile concentration led to the conclusion that most parameters have opposite effects on chromatographic and mass spectrometric performances. The use of acetonitrile as sheath liquid enabled the rapid and highly efficient separation and detection of phosphorylated and nonphosphorylated oligonucleotides ranging in size from 8 to 40 nucleotides. High-quality full-scan mass spectra showing little cation adduction were acquired from which the molecular masses of the separated oligonucleotides were calculated with an accuracy of 0.011%. With calibration curves being linear over at least 2 orders of magnitude, the lower limits of detection for a oligodeoxythymidine 16-mer were 104 fmol with full scan and 710 amol with selected-ion-monitoring data acquisition. The potential of ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry was demonstrated for mixed-sequence oligomers by the characterization of a reaction mixture from solid-phase synthesis of a 40-mer oligonucleotide.

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

    Science.gov (United States)

    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 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

  7. In-house-made capillary electrophoresis instruments coupled with contactless conductivity detection as a simple and inexpensive solution for water analysis: a case study in Vietnam.

    Science.gov (United States)

    Duong, Hong Anh; Le, Minh Duc; Nguyen, Kim Diem Mai; Hauser, Peter C; Pham, Hung Viet; Mai, Thanh Duc

    2015-11-01

    A simple and inexpensive method for the determination of various ionic species in different water matrices is discussed in this study. The approach is based on the employment of in-house-made capillary electrophoresis (CE) instruments with capacitively coupled contactless conductivity detection (C(4)D), which can be realized even when only a modest financial budget and limited expertise are available. Advantageous features and considerations of these instruments are detailed following their pilot deployment in Vietnam. Different categories of ionic species, namely major inorganic cations (K(+), Na(+), Ca(2+), Mg(2+), and NH4(+)) and major inorganic anions (Cl(-), NO3(-), NO2(-), SO4(2-), and phosphate), in different water matrices in Vietnam were determined using these in-house fabricated instruments. Inorganic trivalent arsenic (As(iii)), which is the most abundant form of arsenic in reducing groundwater, was determined by CE-C(4)D. The effect of some interfering ions in groundwater on the analytical performance was investigated and is highlighted. The results from in-house-made CE-C(4)D-instruments were cross-checked with those obtained using the standard methods (AAS, AES, UV and IC), with correlation coefficients r(2) ≥ 0.9 and deviations from the referenced results less than 15%.

  8. Development and validation of a capillary electrophoresis method with capacitively coupled contactless conductivity detection (CE-C(4) D) for the analysis of amikacin and its related substances.

    Science.gov (United States)

    El-Attug, Mohamed Nouri; Adams, Erwin; Van Schepdael, Ann

    2012-09-01

    Amikacin is a semisynthetic aminoglycoside antibiotic derived from kanamycin A that lacks a strong UV absorbing chromophore or fluorophore. Due to the physicochemical properties of amikacin and its related substances, CE in combination with capacitively coupled contactless conductivity detection (CE-C(4) D) was chosen. The optimized separation method uses a BGE composed of 20 mM MES adjusted to pH 6.6 by l-histidine and 0.3 mM CTAB that was added as flow modifier in a concentration below the CMC. Ammonium acetate 20 mg.L(-1) was used as internal standard. 30 kV was applied in reverse polarity on a fused silica capillary (73/48 cm; 75 μm id). The optimized separation was obtained in less than 6 min with good linearity (R(2) = 0.9996) for amikacin base. It shows a good precision expressed as RSD on relative peak areas equal to 0.1 and 0.7% for intraday and interday, respectively. The LOD and LOQ are 0.5 mg.L(-1) and 1.7 mg.L(-1) , respectively. PMID:22965725

  9. Electrophoretic deposition of manganese dioxide-multiwalled carbon nanotube composites for electrochemical supercapacitors.

    Science.gov (United States)

    Wang, Yaohui; Zhitomirsky, Igor

    2009-09-01

    The cathodic electrophoretic deposition (EPD) method has been developed for the deposition of composite manganese dioxide-multiwalled carbon nanotube (MWCNT) films. Dopamine (DA) was shown to be an effective charging additive, which provides stabilization of manganese dioxide nanoparticles and MWCNTs in the suspensions. The influence of DA concentration on the deposition efficiency has been studied. EPD has been utilized for the fabrication of porous nanostructured films for application in electrochemical supercapacitors (ES). Obtained films were studied using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), cyclic voltammetry (CV), and impedance spectroscopy. CV data for the films tested in the 0.5 M Na(2)SO(4) solutions showed capacitive behavior in the voltage window of 0-0.9 V. The highest specific capacitance (SC) of approximately 650 F g(-1) was obtained at a scan rate of 2 mV s(-1). The SC decreased with an increasing scan rate in the range of 2-100 mV s(-1). The deposition mechanism, kinetics of deposition, and charge storage properties of the films are discussed. PMID:19449813

  10. Perfil hematológico e avaliação eletroforética das proteínas séricas de cães com cinomose Hematological profile and electrophoretic evaluation of serum proteins of dogs with canine distemper

    OpenAIRE

    I.N.G. Silva; M.I.F. Guedes; Rocha, M. F. G.; C.M.O. Medeiros; L.C. Oliveira; Moreira, O. C.; M.F.S. Teixeira

    2005-01-01

    The hematological and serum proteins electrophoretic profiles of 13 dogs with distemper (Lentz inclusion body in leukocytes) were studied. The most frequent hematological findings were: normocitic normocromic anemia (61%), leukopenia (46%), left shount (54%), trombocytopenia (69%) and lymphopenia (85%). Electrophoretic analysis of serum proteins showed hypoproteinemia (54%), with reduced albumin and increased alfa-2 globulin. These findings can be used to support the clinical diagnosis of can...

  11. Advances in Automation and Throughput of the Mars Organic Analyzer Microchip Capillary Electrophoresis System

    Science.gov (United States)

    Haldeman, B. J.; Skelley, A. M.; Scherer, J. R.; Jayarajah, C.; Mathies, R. A.

    2005-12-01

    We have previously demonstrated the design, construction and testing of a portable microchip capillary electrophoresis (CE) instrument called the Mars Organic Analyzer (MOA) for analysis of amino acids and amine containing organic molecules (1). This instrument is designed to accept organic compounds isolated from samples by sublimation or by subcritical water extraction, to label the amine groups with fluorescamine, and to perform high resolution electrophoretic analysis. The CE instrument has shown remarkable robustness during successful field tests last year in the Panoche Valley, CA (1) and more recently in the Atacama Desert, Chile (2). For successful operation on Mars, however, it is necessary to operate autonomously and to analyze large numbers of samples, blanks, and standards. Toward this end we present here two advances in the MOA system that test key aspects of an eventual flight prototype. First, we have developed an automated microfluidic system and method for the autonomous loading, running and cleaning of the CE chip on the single channel MOA instrument. The integration of microfabricated PDMS valves and pumps with all-glass separation channels in a multilayer design enabled creation of structures for complex fluidic routing. Twenty sequential analyses of an amino acid standard were performed with an automated cleaning procedure between runs. In addition, dilutions were performed on-chip, and blanks were run to demonstrate the elimination of carry-over from run to run. These results demonstrate an important advance of the technology readiness level of the MOA. Second, we have designed, constructed and successfully tested a lab version of the multichannel instrument we initially proposed for the MSL opportunity. The portable Multi-Channel Mars Organic Analyzer (McMOA, 25 by 30 by 15 cm), was designed to sequentially interrogate eight radially oriented CE separation channels on a single wafer. Since each channel can be used to analyze 20 or more

  12. CMOS absorbance detection system for capillary electrophoresis

    International Nuclear Information System (INIS)

    This paper presents a cost-effective portable photodetection system for capillary electrophoresis absorptiometry. By using a CMOS BDJ (buried double p-n junction) detector, a dual-wavelength method for absorbance measurement is implemented. This system includes associated electronics for low-noise pre-amplification and A/D conversion, followed by digital signal acquisition and processing. Two signal processing approaches are adopted to enhance the signal to noise ratio. One is variable time synchronous detection, which optimizes the sensitivity and measuring rate compared to a conventional synchronous detection technique. The other is a statistical approach based on principal component analysis, which allows optimal estimation of detected signal. This system has been designed and tested in capillary electrophoresis conditions. Its operation has been verified with performances comparable to those of a commercialized spectrophotometric system (HP-3D CE). With potential on-chip integration of associated electronics, it may be operated as an integrable detection module for microchip electrophoresis and other microanalysis systems

  13. Exponential asymptotics and capillary waves

    OpenAIRE

    Chapman, S. J.; Vanden-Broeck, J.

    2002-01-01

    Recently developed techniques in exponential asymptotics beyond all orders are employed on the problem of potential flows with a free surface and small surface tension, in the absence of gravity. Exponentially small capillary waves are found to be generated on the free surface where the equipotentials from singularities in the flow (for example, stagnation points and corners) meet it. The amplitude of these waves is determined, and the implications are considered for many quite general flows....

  14. Capillary electrophoresis in food authenticity.

    Science.gov (United States)

    Kvasnicka, Frantisek

    2005-06-01

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

  15. Inertial Rise in Short Capillaries

    CERN Document Server

    Shardt, Orest; Derksen, J J; Mitra, Sushanta K

    2013-01-01

    In this fluid dynamics video we show capillary rise experiments with diethyl ether in short tubes. The height of each short tube is less than the maximum height the liquid can achieve, and therefore the liquid reaches the top of the tube while still rising. Over a narrow range of heights, the ether bulges out from the top of the tube and spreads onto the external wall.

  16. Characterization and oxidation behavior of NiCoCrAlY coating fabricated by electrophoretic deposition and vacuum heat treatment

    Science.gov (United States)

    Li, Zhiming; Qian, Shiqiang; Wang, Wei

    2011-03-01

    Electrophoretic deposition (EPD) was showed to be a feasible and convenient method to fabricate NiCoCrAlY coatings on nickel based supperalloys. The microstructure and composition of the NiCoCrAlY coatings after vacuum heat treatment were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX). Isothermal-oxidation test was performed at 1100 °C in static air for 100 h. The results show that the major phases in electrophoretic deposited and vacuum heat treated NiCoCrAlY coating are γ-Ni and γ‧-Ni3Al phases, also there is an extremely small quantity of Al2O3 in the coating. Composition fluctuations occur in the coating and a certain amount of titanium diffuse from the superalloy substrate to the top of the coating during vacuum heat treatment. The oxidation test results exhibit that the oxidation kinetics of this coating has two typical stages. The protective oxide layer is mainly formed in the initial linear growth stage and then the oxide layer hinders further oxidation of the coating in the subsequent parabolic growth stage. The coating can effectively protect the superalloy substrate from oxidation. A certain amount of rutile TiO2 is formed in the coating during oxidation and it is adverse to the oxidation resistance of the coating.

  17. Electrophoretic deposition of ZnO/alginate and ZnO-bioactive glass/alginate composite coatings for antimicrobial applications

    Energy Technology Data Exchange (ETDEWEB)

    Cordero-Arias, L.; Cabanas-Polo, S.; Goudouri, O.M. [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, D-91058 Erlangen (Germany); Misra, S.K. [Materials Science and Engineering, Indian Institute of Technology Gandhinagar, Ahmedabad 382424 (India); Gilabert, J. [Institute of Ceramics Materials (ITC), University Jaume I, Avenida Vicent SosBaynat, 12006 Castellon (Spain); Valsami-Jones, E. [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Sanchez, E. [Institute of Ceramics Materials (ITC), University Jaume I, Avenida Vicent SosBaynat, 12006 Castellon (Spain); Virtanen, S. [Institute for Surface Science and Corrosion (LKO, WW4), Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen (Germany); Boccaccini, A.R., E-mail: aldo.boccaccini@ww.uni-erlangen.de [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, D-91058 Erlangen (Germany)

    2015-10-01

    Two organic/inorganic composite coatings based on alginate, as organic matrix, and zinc oxide nanoparticles (n-ZnO) with and without bioactive glass (BG), as inorganic components, intended for biomedical applications, were developed by electrophoretic deposition (EPD). Different n-ZnO (1–10 g/L) and BG (1–1.5 g/L) contents were studied for a fixed alginate concentration (2 g/L). The presence of n-ZnO was confirmed to impart antibacterial properties to the coatings against gram-negative bacteria Escherichia coli, while the BG induced the formation of hydroxyapatite on coating surfaces thereby imparting bioactivity, making the coating suitable for bone replacement applications. Coating composition was analyzed by thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analyses. Scanning electron microscopy (SEM) was employed to study both the surface and the cross section morphology of the coatings. Polarization curves of the coated substrates made in cell culture media at 37 °C confirmed the corrosion protection function of the novel organic/inorganic composite coatings. - Highlights: • Organic–inorganic nanocomposite coatings fabricated by electrophoretic deposition • nZnO and bioactive glass containing alginate coatings exhibit antibacterial effect. • Bioactive character and anticorrosion function of coatings demonstrated.

  18. Separation of poly(acrylic acid) salts according to topology using capillary electrophoresis in the critical conditions.

    Science.gov (United States)

    Maniego, Alison R; Ang, Dale; Guillaneuf, Yohann; Lefay, Catherine; Gigmes, Didier; Aldrich-Wright, Janice R; Gaborieau, Marianne; Castignolles, Patrice

    2013-11-01

    Branching was detected in polyacrylates synthesised through radical polymerization via solution-state NMR, while inconsistencies have been reported for the determination of the molar mass of hydrophilic polyacrylates using aqueous-phase and organic-phase size-exclusion chromatography. In this work, poly(sodium acrylate)s, PNaAs, of various topologies were separated for the first time using free-solution capillary electrophoresis (CE). Free-solution CE does not separate the PNaAs by their molar mass, similarly to separations by liquid chromatography in the critical conditions, rather by different topologies (linear, star branched, and hyperbranched). The electrophoretic mobility of PNaAs increases as the degree of branching decreases. Separation is shown to be not only by the topology but also by the end groups as expected for a separation in the critical conditions: replacing a relatively bulky nitroxide end group with hydrogen atom yielded a higher electrophoretic mobility. This novel method, capillary electrophoresis in the critical conditions enabled, for the first time, the separation of hydrophilic polyacrylates according to their topology (branching) and their chain ends. This will allow meaningful and accurate characterization of their branched topologies as well as molar masses and progress in for advanced applications such as drug delivery or flocculation. PMID:23732867

  19. Temporal redistribution of plantar pressure points in diabetic and control subjects: A time-series analysis of neuro-capillary chaos

    Directory of Open Access Journals (Sweden)

    Devesh V Oberoi

    2010-02-01

    Full Text Available BackgroundIn diabetic individuals (DI, neuropathy hinders theredistribution of plantar pressure points thus leading tosusceptible areas where there is constant capillaryblanching which may develop into trophic ulcers. Theredistribution of pressure points may precede evidenceof clinical neuropathy. In this study we comparetemporal redistribution of plantar pressure points (areasof capillary blanching between normal subjects taken ascontrols and DI with no clinical signs of neuropathy.MethodFour adults (45±4.55 years diagnosed to have Type-2Diabetes, without signs of clinical neuropathy andage -matched controls (43±3.74 years were studied.The subjects were asked to stand on a glass slab and a10 minute video recording of 10 selected plantarpressure points was made. Changes in the distance ofthese points with reference to a defined point onMayer’s line were measured at every 10 seconds.Standard deviation of difference of redistributedconsecutive pressure point (SDPP in cms., andfractal dimension (FD was used to compare the twogroups.ResultsCombined mean SDPP (DI =0.013 ± 0.008 cms,controls= 0.196±0.233 cms, P <0.001 and FD (DI=1.000 ± 0.000, controls= 1.010±0.017, P <0.001 ofdiabetic patients were significantly lower thancontrols. Pressure point at base of the 4th toe andthe lower limit of blanching to the left Mayers line atthe heel did not differ significantly between DI andcontrols.ConclusionThere is impaired redistribution of plantar pressurepoints in individuals with diabetes without signs ofclinical neuropathy. This can be attributed to loss ofchaos generating mechanisms in DI. Redistributionof pressure points may be essential in theprevention of trophic ulcers in susceptibleindividuals.

  20. A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian-Bo, E-mail: jbhe@hfut.edu.cn; Cui, Ting; Zhang, Wen-Wen; Deng, Ning

    2013-07-05

    Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products.

  1. Triple-channel portable capillary electrophoresis instrument with individual background electrolytes for the concurrent separations of anionic and cationic species.

    Science.gov (United States)

    Mai, Thanh Duc; Le, Minh Duc; Sáiz, Jorge; Duong, Hong Anh; Koenka, Israel Joel; Pham, Hung Viet; Hauser, Peter C

    2016-03-10

    The portable capillary electrophoresis instrument is automated and features three independent channels with different background electrolytes to allow the concurrent optimized determination of three different categories of charged analytes. The fluidic system is based on a miniature manifold which is based on mechanically milled channels for injection of samples and buffers. The planar manifold pattern was designed to minimize the number of electronic valves required for each channel. The system utilizes pneumatic pressurization to transport solutions at the grounded as well as the high voltage side of the separation capillaries. The instrument has a compact design, with all components arranged in a briefcase with dimensions of 45 (w) × 35 (d) × 15 cm (h) and a weight of about 15 kg. It can operate continuously for 8 h in the battery-powered mode if only one electrophoresis channel is in use, or for about 2.5 h in the case of simultaneous employment of all three channels. The different operations, i.e. capillary flushing, rinsing of the interfaces at both capillary ends, sample injection and electrophoretic separation, are activated automatically with a control program featuring a graphical user interface. For demonstration, the system was employed successfully for the concurrent separation of different inorganic cations and anions, organic preservatives, additives and artificial sweeteners in various beverage and food matrices. PMID:26893094

  2. Critical Capillary Number of Interfacial Film Displacement in a Capillary Tube

    CERN Document Server

    Yan, Changfei

    2016-01-01

    The role of surface tension and wettability in the dynamics of air-liquid interfaces during immiscible fluid displacement flows in capillary tube driven by pressure has been investigated. The contact angle and capillary number drive the force wetting processes which is controlled by the balance between the capillary and the viscous lubrication forces. The dynamic wetting condition with the critical capillary number is studied analytically and validated experimentally, which demonstrates that the critical capillary number is associated with the contact angle, slip length and capillary radius.

  3. Progression of Diabetic Capillary Occlusion: A Model.

    Directory of Open Access Journals (Sweden)

    Xiao Fu

    2016-06-01

    Full Text Available 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.

  4. Density functional study of condensation in capped capillaries

    Science.gov (United States)

    Yatsyshin, P.; Savva, N.; Kalliadasis, S.

    2015-07-01

    We study liquid adsorption in narrow rectangular capped capillaries formed by capping two parallel planar walls (a slit pore) with a third wall orthogonal to the two planar walls. The most important transition in confined fluids is arguably condensation, where the pore becomes filled with the liquid phase which is metastable in the bulk. Depending on the temperature T, the condensation in capped capillaries can be first-order (at T≤slant {{T}\\text{cw}} ) or continuous (at T\\gt {{T}\\text{cw}} ), where {{T}\\text{cw}} is the capillary wetting temperature. At T \\gt {{T}\\text{cw}} , the capping wall can adsorb mesoscopic amounts of metastable under-condensed liquid. The onset of condensation is then manifested by the continuous unbinding of the interface between the liquid adsorbed on the capping wall and the gas filling the rest of the capillary volume. In wide capped capillaries there may be a remnant of wedge filling transition, which is manifested by the adsorption of liquid drops in the corners. Our classical statistical mechanical treatment predicts a possibility of three-phase coexistence between gas, corner drops and liquid slabs adsorbed on the capping wall. In sufficiently wide capillaries we find that thick prewetting films of finite length may be nucleated at the capping wall below the boundary of the prewetting transition. Prewetting then proceeds in a continuous manner manifested by the unbinding interface between the thick and thin films adsorbed on the side walls. Our analysis is based on a detailed numerical investigation of the density functional theory for the fluid equilibria for a number of illustrative case studies.

  5. Experimental and simulation investigation of ion transfer in different sampling capillaries.

    Science.gov (United States)

    Yu, Quan; Jiang, Tao; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

    2015-12-01

    Atmospheric pressure interfaces were a fundamental structure for transferring air generated ions into the vacuum manifold of a mass spectrometer. This work is devoted to the characterization of ion transfer in metal capillaries through both experimental and simulated investigations. The impact of capillary configurations on ion transmission efficiency was evaluated using an electrospray mass spectrometer with various bent capillaries as the transfer devices. In addition, a numerical model has been set up by coupling the SIMION 8.0 and the computational flow dynamics for simulation study of ion migration in the complex atmospheric system. The transfer efficiency was found to be highly affected by the variation in electric field and the capillary geometry, revealing that the hydrodynamic and electric force were both dominant and interactional during the transmission process. The consistency of the results from the experimental analysis and simulation modeling proved the validity of the model, which was helpful for understanding ion activity in transfer capillaries. PMID:26634970

  6. Development of a capillary electrophoresis method for the simultaneous determination of cephalosporins

    Directory of Open Access Journals (Sweden)

    Hancu Gabriel

    2013-01-01

    Full Text Available A rapid and simple capillary electrophoresis method has been developed for the simultaneous determination of six extensively used cephalosporin antibiotics (cefaclor, cefadroxil, cefalexin, cefuroxim, ceftazidim, ceftriaxon. The determination of cephalosporins was performed at a pH 6.8, using a 25 mM phospate - 25 mM borate mixed buffer, + 25 kV voltage at a temperature of 25 °C. We achieved a baseline separation in approximately 10 minutes. The separation resolution was increased by addition of an anionic surfactant, 50 mM sodium dodecyl sulfate, to the buffer solution. The proposed separation was evaluated on the basis of detection and quantification limits, effective electrophoretic mobility and relative standard deviation for migration times and peak areas.

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

    Science.gov (United States)

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

    2004-12-24

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

  8. Investigation of interaction between the drug and cell membrane by capillary electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By introducing cell membrane into electrophoretic buffer as pseudo-stationary phase,a novel capillary electrophoresis method was established to explore the interaction between drugs and cell membrane,where the interaction between citalopram and rabbit red blood cell membrane was used as an example. A series of concentrations of cell membrane were suspended into the running buffer by peak-shift method. The binding constant of citalopram to rabbit red blood cell membrane of 0.977 g-1·L was obtained after treatment of Scatchard plot. This method could provide not only a new way for the investigation on the interactions between drugs and cell membrane,but also a new approach for high throughput screening of the drug membrane permeability,biological activity,and evaluating drugs in vivo.

  9. Photoelectrochemical Behavior of Electrophoretically Deposited Hematite Thin Films Modified with Ti(IV).

    Science.gov (United States)

    Dalle Carbonare, Nicola; Boaretto, Rita; Caramori, Stefano; Argazzi, Roberto; Dal Colle, Maurizio; Pasquini, Luca; Bertoncello, Renzo; Marelli, Marcello; Evangelisti, Claudio; Bignozzi, Carlo Alberto

    2016-01-01

    Doping hematite with different elements is a common strategy to improve the electrocatalytic activity towards the water oxidation reaction, although the exact effect of these external agents is not yet clearly understood. Using a feasible electrophoretic procedure, we prepared modified hematite films by introducing in the deposition solution Ti(IV) butoxide. Photoelectrochemical performances of all the modified electrodes were superior to the unmodified one, with a 4-fold increase in the photocurrent at 0.65 V vs. SCE in 0.1 M NaOH (pH 13.3) for the 5% Ti-modified electrode, which was the best performing electrode. Subsequent functionalization with an iron-based catalyst led, at the same potential, to a photocurrent of ca. 1.5 mA·cm(-2), one of the highest achieved with materials based on solution processing in the absence of precious elements. AFM, XPS, TEM and XANES analyses revealed the formation of different Ti(IV) oxide phases on the hematite surface, that can reduce surface state recombination and enhance hole injection through local surface field effects, as confirmed by electrochemical impedance analysis. PMID:27447604

  10. Observation of separate cation and anion electrophoretic mobilities in pure ionic liquids

    Science.gov (United States)

    Zhang, Zhiyang; Madsen, Louis A.

    2014-02-01

    Ionic liquids (ILs) continue to show relevance in many fields, from battery electrolytes, to carbon capture, to advanced separations. These highly ion-dense fluids present unique challenges in understanding their electrochemical properties due to deviations in behavior from existing electrolyte theories. Here we present a novel characterization of ILs using electrophoretic NMR (ENMR) to determine separate cation and anion mobilities. This method uses an applied electric field coincident with a pulsed magnetic field gradient to encode the E-field driven flow into NMR signals for cations (1H) and anions (19F). We describe the detailed design of these experiments, including quantitative analysis of artifact mitigation and necessary control experiments. We then explore mobilities and diffusion coefficients for two representative ILs: 1-ethyl-3-methyl imidazolium tetrafluoroborate ([C2mim][BF4]) and 1-ethyl-3-methyl imidazolium trifluoromethanesulfonate ([C2mim][TfO]). We further use the individual ion mobilities to calculate the bulk net conductivity, which closely agrees with bulk conductivity measurements obtained using impedance spectroscopy. These observations represent the first reliable measurements of cation and anion mobilities in pure ILs, with errors of ±7%. We discuss this advanced experimental methodology in detail, as well as implications of these sensitive measurements for understanding conduction mechanisms in ion-dense electrolytes.

  11. Photoelectrochemical Behavior of Electrophoretically Deposited Hematite Thin Films Modified with Ti(IV

    Directory of Open Access Journals (Sweden)

    Nicola Dalle Carbonare

    2016-07-01

    Full Text Available Doping hematite with different elements is a common strategy to improve the electrocatalytic activity towards the water oxidation reaction, although the exact effect of these external agents is not yet clearly understood. Using a feasible electrophoretic procedure, we prepared modified hematite films by introducing in the deposition solution Ti(IV butoxide. Photoelectrochemical performances of all the modified electrodes were superior to the unmodified one, with a 4-fold increase in the photocurrent at 0.65 V vs. SCE in 0.1 M NaOH (pH 13.3 for the 5% Ti-modified electrode, which was the best performing electrode. Subsequent functionalization with an iron-based catalyst led, at the same potential, to a photocurrent of ca. 1.5 mA·cm−2, one of the highest achieved with materials based on solution processing in the absence of precious elements. AFM, XPS, TEM and XANES analyses revealed the formation of different Ti(IV oxide phases on the hematite surface, that can reduce surface state recombination and enhance hole injection through local surface field effects, as confirmed by electrochemical impedance analysis.

  12. Electrophoretic nanotechnology of graphene-carbon nanotube and graphene-polypyrrole nanofiber composites for electrochemical supercapacitors.

    Science.gov (United States)

    Shi, Kaiyuan; Zhitomirsky, Igor

    2013-10-01

    Thin films of multiwalled carbon nanotubes (MWCNT), graphene and polypyrrole (PPy) nanofibers were prepared by cathodic electrophoretic deposition (EPD) from aqueous suspensions, containing safranin (SAF) as a new dispersant. The results of Fourier transform infrared spectroscopy, UV-Vis spectroscopy studies and sedimentation tests, coupled with deposition yield and electron microscopy data showed that SAF adsorbed on MWCNT, graphene and PPy, provided their dispersion and charging in the suspensions and allowed efficient EPD. The deposition yield can be controlled by the variation of SAF concentration in the suspensions and deposition time. The use of SAF as a co-dispersant for MWCNT, graphene and PPy, allowed controlled EPD of composite graphene-MWCNT and graphene-PPy films. The proposed approach for the deposition of PPy paves the way for EPD of neutral polymers using organic dyes as dispersing and charging agents. The composite films were investigated for application in electrochemical supercapacitors (ES). The graphene-MWCNT and graphene-PPy films showed significant increase in capacitance, decrease in resistance and increase in capacitance retention at high charge-discharge rates compared to the films of individual components. The analysis of electrochemical testing results and electron microscopy data provided an insight into the influence of composite microstructure on electrochemical performance. The composites, prepared by EPD are promising materials for electrodes of ES. PMID:23880521

  13. The Effect of Deposition Time on Textured Magnesium Diboride Thick Films Fabricated by Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    W. G. Mutia

    2004-12-01

    Full Text Available MgB2 powders suspended in ethanol were electrophoretically deposited on high-purity molybdenum substrates having dimensions of 1 x 0.3 x 0.01 cm. The said substrate was set as the cathode and was placed 0.5 cm away from a graphite rod anode. A current density of ~0.02 mA/cm2 and a voltage of 600 V were applied. The effect of deposition time was studied by varying it as follows: 15 s, 30 s, 1 min, and 2 min. Heat treatment at 950 oC for 3 h was done after deposition. MgB2 thick films were successfully fabricated for the deposition carried out for 2 min. Deposition times less than 2 min resulted in insufficient deposited powder; hence formation of MgB2 was not facilitated. Films deposited at 15 and 30 s have good surface characteristics, wherein no microcracks were present. X-ray diffraction and surface image analysis reveal that the deposited films have a preferred orientation along the (10l direction.

  14. Electrodeposition of Cu-Pd alloys onto electrophoretic deposited carbon nanotubes for nitrate electroreduction

    International Nuclear Information System (INIS)

    Copper-palladium (Cu-Pd) alloys have been electrodeposited onto carbon nanotubes, which were uniformly and stably deposited on Ti plates via electrophoretic deposition. Electrodes with a wide range of Cu/Pd atomic ratios were fabricated by potentiostatic coelectrodeposition of Cu and Pd onto Ti/CNTs. They were characterized by energy-dispersive X-ray analyzer, X-ray diffraction and tested for nitrate electroreduction. The electrode deposited in bath with 5 mM Cu2+ and 5 mM Pd2+ (Ti/CNTs/Cu5-Pd5) possessed outstanding stability as well as the highest electrocatalytic activity with the best nitrate conversion yield and proper N2 selectivity, indicating a synergistic effect of Cu and Pd. X-ray photoelectron spectroscopy and scanning electron microscopy analysis of Ti/CNTs/Cu5-Pd5 and Ti/Cu5-Pd5 revealed that CNTs played a remarkable role in the homogeneous formation of the bimetal, significantly improving the alloy's electrocatalytic activity and stability. The fabricated Ti/CNTs/Cu5-Pd5 was proved to be a promising electrode for nitrate electroreduction.

  15. The effect of capillary pressure for concave liquid-vapor interface on interfacial evaporation

    Institute of Scientific and Technical Information of China (English)

    张金涛; 王补宣; 彭晓峰

    2001-01-01

    The analysis in this paper demonstrates that the capillary pressure on the concave liquid-vapor interface will promote the interfacial evaporation, therefore clarifying the confusion over the great difference between the estimated and real rate of interfacial evaporation. This difference increases with decreasing capillary radius, and becomes more apparent for liquid with high latent heat. The present analysis also shows that the capillary pressure on the concave interface will result in a decrease in liquid phase equilibrium temperature, which can explain the possibility of vapor bubble formation on micro liquid layer interfacial evaporation under low superheat, or even below the nominal saturated temperature.

  16. Numerical Simulation of Particle Distribution in Capillary Membrane during Backwash

    Directory of Open Access Journals (Sweden)

    Anik Keller

    2013-09-01

    Full Text Available The membrane filtration with inside-out dead-end driven UF-/MF- capillary membranes is an effective process for particle removal in water treatment. Its industrial application increased in the last decade exponentially. To date, the research activities in this field were aimed first of all at the analysis of filtration phenomena disregarding the influence of backwash on the operation parameters of filtration plants. However, following the main hypothesis of this paper, backwash has great potential to increase the efficiency of filtration. In this paper, a numerical approach for a detailed study of fluid dynamic processes in capillary membranes during backwash is presented. The effect of particle size and inlet flux on the backwash process are investigated. The evaluation of these data concentrates on the analysis of particle behavior in the cross sectional plane and the appearance of eventually formed particle plugs inside the membrane capillary. Simulations are conducted in dead-end filtration mode and with two configurations. The first configuration includes a particle concentration of 10% homogeneously distributed within the capillary and the second configuration demonstrates a cake layer on the membrane surface with a packing density of 0:6. Analyzing the hydrodynamic forces acting on the particles shows that the lift force plays the main role in defining the particle enrichment areas. The operation parameters contribute in enhancing the lift force and the heterogeneity to anticipate the clogging of the membrane.

  17. Capillary pumped loop body heat exchanger

    Science.gov (United States)

    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.

  18. Controlled method of reducing electrophoretic mobility of macromolecules, particles, or cells

    Science.gov (United States)

    Vanalstine, James M. (Inventor)

    1992-01-01

    A method of reducing electrophoretic mobility of macromolecules, particles, cells, and other substances is provided which comprises interacting in a conventional electrophoretic separating procedure, the substances with a polymer-linked affinity compound comprised of a hydrophilic neutral polymer such as polyethylene glycol bound to a second component such as a hydrophobic compound, an immunocompound such as an antibody or antibody active fragment, or a ligand such as a hormone, drug, antigen, or a hapten. The reduction of electrophoretic mobility achieved is directly proportional to the concentration of the polymer-linked affinity compound employed, and such reduction can comprise up to 100 percent for particular particles and cells. The present invention is advantageous in that electrophoretic separation can now be achieved for substances whose native surface charge structure had prevented them from being separated by normal electrophoretic means. Depending on the affinity component utilized, separation can be achieved on the basis of the specific/irreversible, specific/reversible, semi-specific/reversible, relatively nonspecific/reversible, or relatively nonspecific/irreversible ligand-substance interactions.

  19. The electrophoretic mobility of montmorillonite. Zeta potential and surface conductivity effects.

    Science.gov (United States)

    Leroy, Philippe; Tournassat, Christophe; Bernard, Olivier; Devau, Nicolas; Azaroual, Mohamed

    2015-08-01

    Clay minerals have remarkable adsorption properties because of their high specific surface area and surface charge density, which give rise to high electrochemical properties. These electrochemical properties cannot be directly measured, and models must be developed to estimate the electrostatic potential at the vicinity of clay mineral surfaces. In this context, an important model prediction is the zeta potential, which is thought to be representative of the electrostatic potential at the plane of shear. The zeta potential is usually deduced from electrophoretic measurements but for clay minerals, high surface conductivity decreases their mobility, thereby impeding straightforward interpretation of these measurements. By combining a surface complexation, conductivity and electrophoretic mobility model, we were able to reconcile zeta potential predictions with electrophoretic measurements on montmorillonite immersed in NaCl aqueous solutions. The electrochemical properties of the Stern and diffuse layers of the basal surfaces were computed by a triple-layer model. Computed zeta potentials have considerably higher amplitudes than measured zeta potentials calculated with the Smoluchowski equation. Our model successfully reproduced measured electrophoretic mobilities. This confirmed our assumptions that surface conductivity may be responsible for montmorillonite's low electrophoretic mobility and that the zeta potential may be located at the beginning of the diffuse layer. PMID:25875489

  20. Fabrication and kinetics study of nano-Al/NiO thermite film by electrophoretic deposition.

    Science.gov (United States)

    Zhang, Daixiong; Li, Xueming

    2015-05-21

    Nano-Al/NiO thermites were successfully prepared as film by electrophoretic deposition (EPD). For the key issue of this EPD, a mixture solvent of ethanol-acetylacetone (1:1 in volume) containing 0.00025 M nitric acid was proved to be a suitable dispersion system for EPD. The kinetics of electrophoretic deposition for both nano-Al and nano-NiO were investigated; the linear relation between deposition weight and deposition time in short time and parabolic relation in prolonged time were observed in both EPDs. The critical transition time between linear deposition kinetics and parabolic deposition kinetics for nano-Al and nano-NiO were 20 and 10 min, respectively. The theoretical calculation of the kinetics of electrophoretic deposition revealed that the equivalence ratio of nano-Al/NiO thermites film would be affected by the behavior of electrophoretic deposition for nano-Al and nano-NiO. The equivalence ratio remained steady when the linear deposition kinetics dominated for both nano-Al and nano-NiO. The equivalence ratio would change with deposition time when deposition kinetics for nano-NiO changed into parabolic kinetics dominated after 10 min. Therefore, the rule was suggested to be suitable for other EPD of bicomposites. We also studied thermodynamic properties of electrophoretic nano-Al/NiO thermites film as well as combustion performance. PMID:25950271

  1. A New Conductivity Detector for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  2. Ultrastructural, autoradiographic and electrophoretic examinations of Chara tomentosa spermiogenesis

    Directory of Open Access Journals (Sweden)

    Maria Kwiatkowska

    2014-02-01

    Full Text Available Ultrastructure of a spermatid nucleus changes many times during spermiogenesis. Condensed chromatin forms irregular clusters during phases I-II, a continuous ring adjacent to a nuclear envelope during phases III-V and a network occupying the whole nucleus during phase VI. In advanced spermiogenesis dense chromatin disappears and short randomly positioned fibrils arise, then long parallel ones are found (phase VIII which during phase IX form a lamellar structure. In mature spermatozoids (phase X chromatin becomes extremely condensed. 3H-arginine and 3H-lysine incorporation into spermatids during 2-min incubation is intensive during phases IN, decreases during phases VI, VII and becomes very low during phases VIII-IX. Capillary electrophoresis has shown that during Chara tomentosa spermiogenesis replacement of histones with basic proteins whose mobility is comparable to that of salmon protamines takes place. At the beginning of spermiogenesis core and linker histones are found in spermatids. During early spermiogenesis protamine-like proteins appear and their amount increases in late spermiogenesis when core histones are still present. In mature spermatozoids only protamine-like proteins represented by 3 fractions: 9.1 kDa, 9.6 kDa, 11.2 kDa are found. Disappearance of linker histones following their modification precedes disappearance of core histones. The results indicate that dynamic rearrangement of chromatin ultrastructure and aminoacid incorporation rate during spermiogenesis are reflected in basic nuclear protein changes.

  3. The role of the rheological properties of non-newtonian fluids in controlling dispersive mixing in a batch electrophoretic cell with Joule heating

    Directory of Open Access Journals (Sweden)

    M.A. Bosse

    2001-03-01

    Full Text Available The problem of the effect of Joule heating generation on the hydrodynamic profile and the solute transport found in electrophoretic devices is addressed in this article. The research is focused on the following two problems: The first one is centered around the effect of Joule heating on the hydrodynamic velocity profile and it is referred to as "the carrier fluid problem." The other one is related to the effect of Joule heating on the solute transport inside electrophoretic cells and it is referred to as "the solute problem". The hydrodynamic aspects were studied first to yield the velocity profiles required for analysis of the solute transport problem. The velocity profile obtained in this study is analytical and the results are valid for non-Newtonian fluids carriers. To this end, the power-law model was used to study the effect of the rheology of the material in conjunction with the effect of Joule heating generation inside batch electrophoretic devices. This aspect of the research was then effectively used to study the effect of Joule heating generation on the motion of solutes (such as macromolecules under the influence of non-Newtonian carriers. This aspect of the study was performed using an area-averaging approach that yielded analytical results for the effective diffusivity of the device.

  4. Slope wavenumber spectrum models of capillary and capillary-gravity waves

    Institute of Scientific and Technical Information of China (English)

    贾永君; 张杰; 王岩峰

    2010-01-01

    Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using th...

  5. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter

    1999-01-01

    The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then......, the bottom plate is lowered under gravity to produce a specified strain. The sample is thereby stretched into a filament. Provided the filament is sufficiently long, surface tension will induce a thinning of the filament until breakup in finite time. The numerical simulations are performed with a Lagrangian...

  6. Electromigration dispersion in Capillary Electrophoresis

    CERN Document Server

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

    2012-01-01

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

  7. Capillary electrophoresis theory and practice

    CERN Document Server

    Grossman, Paul D

    1992-01-01

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

  8. Capillary Pumped Heat Transfer (CHT) Experiment

    Science.gov (United States)

    Hallinan, Kevin P.; Allen, J. S.

    1998-01-01

    The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

  9. Regulation of skeletal muscle capillary growth in exercise and disease.

    Science.gov (United States)

    Haas, Tara L; Nwadozi, Emmanuel

    2015-12-01

    Capillaries, which are the smallest and most abundant type of blood vessel, form the primary site of gas, nutrient, and waste transfer between the vascular and tissue compartments. Skeletal muscle exhibits the capacity to generate new capillaries (angiogenesis) as an adaptation to exercise training, thus ensuring that the heightened metabolic demand of the active muscle is matched by an improved capacity for distribution of gases, nutrients, and waste products. This review summarizes the current understanding of the regulation of skeletal muscle capillary growth. The multi-step process of angiogenesis is coordinated through the integration of a diverse array of signals associated with hypoxic, metabolic, hemodynamic, and mechanical stresses within the active muscle. The contributions of metabolic and mechanical factors to the modulation of key pro- and anti-angiogenic molecules are discussed within the context of responses to a single aerobic exercise bout and short-term and long-term training. Finally, the paradoxical lack of angiogenesis in peripheral artery disease and diabetes and the implications for disease progression and muscle health are discussed. Future studies that emphasize an integrated analysis of the mechanisms that control skeletal muscle capillary growth will enable development of targeted exercise programs that effectively promote angiogenesis in healthy individuals and in patient populations.

  10. Properties of electrophoretic fractions of human embryonic kidney cells separated on space shuttle flight STS-8

    Science.gov (United States)

    Morrison, Dennis R.; Lewis, Marian L.; Barlow, Grant H.; Todd, Paul; Kunze, M. Elaine; Sarnoff, Burton E.; Li, Zhankui

    Suspensions of cultured primary human embryonic kidney cells were subjected to continuous flow electrophoresis on Space Shuttle flight STS-8. The objectives of the experiments were to obtain electrophoretically separated fractions of the original cell populations and to test these fractions for the amount and kind of urokinase (a kidney plasminogen activator that is used medically for digesting blood clots), the morphologies of cells in the individual fractions, and their cellular electrophoretic mobilities after separation and subsequent proliferation. Individual fractions were successfully cultured after return from orbit, and they were found to differ substantially from one another and from the starting sample with respect to all of these properties.

  11. Capillary electrophoresis for the assay of fixed-dose combination tablets of artesunate and amodiaquine

    Directory of Open Access Journals (Sweden)

    Amin N’Cho

    2012-05-01

    Full Text Available Abstract Background Quality control of drugs in formulations is still a major challenge in developing countries. For the quality control of artesunate and amodiaquine tablets in fixed-dose combination, only liquid chromatographic methods have been proposed in the literature. There are no capillary electrophoretic methods reported for the determination of these active substances, although this technique presents several advantages over liquid chromatography (long lifetime, low price of the capillary, low volumes of electrolyte consumption in addition to simplicity. In this paper, a reliable capillary electrophoresis method has been developed and validated for the quality control of these drugs in commercial fixed-dose combination tablets. Methods Artesunate and amodiaquine hydrochloride in bilayer tablets were determined by micellar electrokinetic capillary chromatography (MEKC. Analytes were extracted from tablets by sonication with a solvent mixture phosphate buffer pH 7.0-acetonitrile containing benzoic acid as internal standard. Separation was carried out on Beckman capillary electrophoresis system equipped with fused silica capillary, 30 cm long (20 cm to detector × 50 μm internal diameter, using a 25 mM borate buffer pH 9.2 containing 30 mM sodium dodecyl sulfate as background electrolyte, a 500 V cm−1 electric field and a detection wavelength of 214 nm. Results Artesunate, amodiaquine and benzoic acid were separated in 6 min. The method was found to be reliable with respect to specificity,linearity of the calibration line (r2 > 0.995, recovery from synthetic tablets (in the range 98–102%, repeatability (RSD 2–3%, n = 7 analytical procedures. Application to four batches of commercial formulations with different dosages gave content in good agreement with the declared content. Conclusion The MEKC method proposed is reliable for the determination of artesunate and amodiaquine hydrochloride in fixed

  12. Atomic Force Controlled Capillary Electrophoresis

    Science.gov (United States)

    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.

  13. Cryogenic Capillary Screen Heat Entrapment

    Science.gov (United States)

    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.

  14. A New Method to Measure Electroosmotic Flow Mobility of Capillary Electrophoresis by Abrupt Change of Current De-noising via Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    LI,Qian-Feng; ZHANG,Xiao-Yun; ZHANG,Hong-Yi; CHEN,Xing-Guo; LIU,Man-Cang; HU,Zhi-De

    2001-01-01

    The electroosmotic flow mobility has been measured by the combination of monitoring the change in electric current dur ing electrophoretic run and operating the wavelet transform. Once the sample solvent zone with different ionic stenggth from background electrolyte migrated from the capillary, a sudden change in current could be observed from the ekectric current record of time history. The exact time (in the middle of abrupt range) corresponding to the abrupt change in cur rent was determined by wavelet transform. This work showed posed method was in a good agreement with the neutral mark er method commonly used.

  15. Recent advances in the development of capillary electrophoresis methodologies for optimizing, controlling, and characterizing the synthesis, functionalization, and physicochemical, properties of nanoparticles.

    Science.gov (United States)

    Trapiella-Alfonso, Laura; d'Orlyé, Fanny; Varenne, Anne

    2016-04-01

    This paper gives a critical overview of capillary electrophoresis (CE) methodologies recently developed for controlling and optimizing the synthesis of nanoparticles as well as characterizing their functionalization in terms of physicochemical properties. Thanks to their electrophoretic mobility, various parameters can be determined, such as NP size and charge distribution, ζ-potential, surface functionality, colloidal stability, grafting rates, and dissociation constants, allowing not only the complete characterization of new nanoprobes but also helping in their design and in the selection of chemical conditions for their storage and further manipulation. New strategies for the improvement of CE detection sensitivity are also described.

  16. Interconverting conformations of variants of the human amyloidogenic protein beta2-microglobulin quantitatively characterized by dynamic capillary electrophoresis and computer simulation

    DEFF Research Database (Denmark)

    Heegaard, Niels H H; Jørgensen, Thomas J D; Cheng, Lei;

    2006-01-01

    Capillary electrophoretic separation profiles of cleaved variants of beta2-microglobulin (beta2m) reflect the conformational equilibria existing in solutions of these proteins. The characterization of these equilibria is of interest since beta2m is responsible for amyloid formation in dialysis......-related amyloidosis and thus is able to attain alternative conformations that lead to irreversible aggregation and precipitation. In this study, we quantitate the increased conformational instability of cleaved beta2m by extracting rate constants and activation energies by simulating the experimental data using...

  17. Methods of analysis and quality-assurance practices of the U.S. Geological Survey organic laboratory, Sacramento, California; determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry

    Science.gov (United States)

    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.

  18. Stereological study of the capillaries in the thyroid gland after IR laser radiation

    Science.gov (United States)

    Perez de Vargas, I.; Vidal, Lourdes; Parrado, C.; Carrillo, F.; Pelaez, A.; Rius, F.

    1994-02-01

    We have planned a stereological ultrastructural study of capillaries in the thyroid gland treated with IR laser radiation and quantified 1 day after the last treatment. Wistar rats, 50 days old, were irradiated with IR laser radiation. The rats were perfused with 2.5 percent glutaraldehyde in 0.1 M phosphate buffer (ph equals 7.4). The pieces obtained after sectioning the thyroid gland were placed immediately into the same fixative. A stereological study of the thyroid capillaries was carried out. This analysis revealed an increase of luminal area in irradiated capillaries.

  19. Capillary Electrophoresis of Substituted Benzoic Acids

    Science.gov (United States)

    Mills, Nancy S.; Spence, John D.; Bushey, Michelle M.

    2005-01-01

    A series of substituted benzoic acids (SBAs) are prepared by students. The pKa shift, a result of the electron-withdrawing or electron-donating characteristics of the subsistent is examined in reference to the electrophoretic migration behavior of benzoic acid.

  20. Template-based growth of titanium dioxide nanorods by a particulate sol-electrophoretic deposition process

    Institute of Scientific and Technical Information of China (English)

    Mohammad Reza Mohammadi; Farideh Ordikhani; Derek J. Fray; Farzad Khornamizadeh

    2011-01-01

    TiO2 nanorods have been successfully grown into a track-etched polycarbonate (PC) membrane by a particulate sol-electrophoretic deposition from an aqueous medium, The prepared sols had a narrow particle size distribution around 17 nm and excellent stability against aging, with zeta potentials in the range of 47-50 mV at pH 2. It was found that TiO2 nanorods were grown from dilute aqueous sol with a Iow, 0.1-M concentration. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that a full conversion of titanium isopropoxide was obtained by hydrolysis, resulting in the formation of TiO2particles. X-ray diffraction (XRD) results revealed that TiO2 nanorods dried at 100°C were a mixture of anatase and brookite phases, whereas they were a mixture of anatase and rutile structures at 500℃.Moreover, the futile content of the TiO2 nanorods was higher than that of TiO2 powders. Transmission electron microscope (TEM) images confirmed that TiO2 nanorods had a smooth morphology and longitudinal uniformity in diameter. Field emission scanning electron microscope (FE-SEM) images showed that Ti02 nanorods grown by sol-electrophoresis from the dilute aqueous sol had a dense structure with a uniform diameter of 200 nm, containing small particles with an average size of 15 nm. Simultaneous differential thermal (SDT) analysis verified that individual TiO2 nanorods, grown into a PC template, were obtained after annealing at 500℃. Based on kinetic studies, it was found that uniform TiO2 nanorods with high-quality morphology were obtained under optimum conditions at an applied potential of 0.3 V/cm and a deposition time or 60 min.

  1. Diagnostics of a high current capillary discharge

    International Nuclear Information System (INIS)

    We have demonstrated that thin (10 to 25 μm diameter) capillaries can be fabricated in suitably configured insulators for use in pulse power machines. Large currents can be used to heat these capillaries which produce photons with an energies greater than 1 keV

  2. Pulmonary capillary haemangiomatosis in a premature infant

    International Nuclear Information System (INIS)

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  3. Pulmonary capillary haemangiomatosis in a premature infant

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cicero J.T.A.; Massie, John; Mandelstam, Simone A. [University of Melbourne, Royal Children' s Hospital, Parkville, VIC (Australia)

    2005-06-01

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  4. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    Science.gov (United States)

    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.

  5. In vitro genotypic variation of Campylobacter coli documented by pulsed-field gel electrophoretic DNA profiling, implications for epidemiological studies

    DEFF Research Database (Denmark)

    On, Stephen L.W.

    1998-01-01

    Six isolates of Campylobacter coli from different pig herds were subcultured up to 50 times over a 6-month period and DNA samples suitable for pulsed-field gel electrophoretic (PFGE) profiling prepared at regular (1, 20, 40 and 50 passages) intervals. In 5/6 strains, changes in the banding patterns...... of Sma1, Sal1 and/or BamH1 digests were observed. In one such strain the differences were considered artifactual. However, significant alterations in PFGE profiles between subcultures of four strains were seen, irrespective of the restriction enzyme used. Spontaneous intramolecular genomic rearrangements...... were considered the most likely mechanism for the changes observed. A numerical analysis based upon the combined distribution of Sma1- and Sal1-derived fragments clustered most strain subcultures together, with the exception of those from one isolate which were divided into two clusters. The effect...

  6. A 502-Base Free-Solution Electrophoretic DNA Sequencing Method Using End-Attached Wormlike Micelles.

    Science.gov (United States)

    Istivan, Stephen B; Bishop, Daniel K; Jones, Angela L; Grosser, Shane T; Schneider, James W

    2015-11-17

    We demonstrate that the use of wormlike nonionic micelles as drag-tags in end-labeled free-solution electrophoresis ("micelle-ELFSE") provides single-base resolution of Sanger sequencing products up to 502 bases in length, a nearly 2-fold improvement over reported ELFSE separations. "CiEj" running buffers containing 48 mM C12E5, 6 mM C10E5, and 3 M urea (32.5 °C) form wormlike micelles that provide a drag equivalent to an uncharged DNA fragment with a length (α) of 509 bases (effective Rh = 27 nm). Runtime in a 40 cm capillary (30 kV) was 35 min for elution of all products down to the 26-base primer. We also show that smaller Triton X-100 micelles give a read length of 103 bases in a 4 min run, so that a combined analysis of the Sanger products using the two buffers in separate capillaries could be completed in 14 min for the full range of lengths. A van Deemter analysis shows that resolution is limited by diffusion-based peak broadening and wall adsorption. Effects of drag-tag polydispersity are not observed, despite the inherent polydispersity of the wormlike micelles. We ascribe this to a stochastic size-sampling process that occurs as micelle size fluctuates rapidly during the runtime. A theoretical model of the process suggests that fluctuations occur with a time scale less than 10 ms, consistent with the monomer exchange process in nonionic micelles. The CiEj buffer has a low viscosity (2.7 cP) and appears to be semidilute in micelle concentration. The large drag-tag size of the CiEj buffers leads to steric segregation of the DNA and tag for short fragments and attendant mobility shifts.

  7. A 502-Base Free-Solution Electrophoretic DNA Sequencing Method Using End-Attached Wormlike Micelles.

    Science.gov (United States)

    Istivan, Stephen B; Bishop, Daniel K; Jones, Angela L; Grosser, Shane T; Schneider, James W

    2015-11-17

    We demonstrate that the use of wormlike nonionic micelles as drag-tags in end-labeled free-solution electrophoresis ("micelle-ELFSE") provides single-base resolution of Sanger sequencing products up to 502 bases in length, a nearly 2-fold improvement over reported ELFSE separations. "CiEj" running buffers containing 48 mM C12E5, 6 mM C10E5, and 3 M urea (32.5 °C) form wormlike micelles that provide a drag equivalent to an uncharged DNA fragment with a length (α) of 509 bases (effective Rh = 27 nm). Runtime in a 40 cm capillary (30 kV) was 35 min for elution of all products down to the 26-base primer. We also show that smaller Triton X-100 micelles give a read length of 103 bases in a 4 min run, so that a combined analysis of the Sanger products using the two buffers in separate capillaries could be completed in 14 min for the full range of lengths. A van Deemter analysis shows that resolution is limited by diffusion-based peak broadening and wall adsorption. Effects of drag-tag polydispersity are not observed, despite the inherent polydispersity of the wormlike micelles. We ascribe this to a stochastic size-sampling process that occurs as micelle size fluctuates rapidly during the runtime. A theoretical model of the process suggests that fluctuations occur with a time scale less than 10 ms, consistent with the monomer exchange process in nonionic micelles. The CiEj buffer has a low viscosity (2.7 cP) and appears to be semidilute in micelle concentration. The large drag-tag size of the CiEj buffers leads to steric segregation of the DNA and tag for short fragments and attendant mobility shifts. PMID:26455271

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2012-08-01

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

  10. The effects of capillary dysfunction on oxygen and glucose extraction in diabetic neuropathy.

    Science.gov (United States)

    Østergaard, Leif; Finnerup, Nanna B; Terkelsen, Astrid J; Olesen, Rasmus A; Drasbek, Kim R; Knudsen, Lone; Jespersen, Sune N; Frystyk, Jan; Charles, Morten; Thomsen, Reimar W; Christiansen, Jens S; Beck-Nielsen, Henning; Jensen, Troels S; Andersen, Henning

    2015-04-01

    Diabetic neuropathy is associated with disturbances in endoneurial metabolism and microvascular morphology, but the roles of these factors in the aetiopathogenesis of diabetic neuropathy remain unclear. Changes in endoneurial capillary morphology and vascular reactivity apparently predate the development of diabetic neuropathy in humans, and in manifest neuropathy, reductions in nerve conduction velocity correlate with the level of endoneurial hypoxia. The idea that microvascular changes cause diabetic neuropathy is contradicted, however, by reports of elevated endoneurial blood flow in early experimental diabetes, and of unaffected blood flow when early histological signs of neuropathy first develop in humans. We recently showed that disturbances in capillary flow patterns, so-called capillary dysfunction, can reduce the amount of oxygen and glucose that can be extracted by the tissue for a given blood flow. In fact, tissue blood flow must be adjusted to ensure sufficient oxygen extraction as capillary dysfunction becomes more severe, thereby changing the normal relationship between tissue oxygenation and blood flow. This review examines the evidence of capillary dysfunction in diabetic neuropathy, and whether the observed relation between endoneurial blood flow and nerve function is consistent with increasingly disturbed capillary flow patterns. The analysis suggests testable relations between capillary dysfunction, tissue hypoxia, aldose reductase activity, oxidative stress, tissue inflammation and glucose clearance from blood. We discuss the implications of these predictions in relation to the prevention and management of diabetic complications in type 1 and type 2 diabetes, and suggest ways of testing these hypotheses in experimental and clinical settings.

  11. Properties of the microcirculation in capillary bundles of rat spinotrapezius muscle fascia

    Science.gov (United States)

    Jacobitz, Frank; Engebrecht, Cheryn; Metzger, Ian; Porterfield, Colin

    2006-11-01

    Properties of the microcirculation in capillary bundles of rat spinotrapezius muscle fascia are investigated using microscope observations, empirical modeling, and numerical simulations. Capillary bundles consist of a network of feeding arterioles, draining venules, and capillary vessels. A dozen samples of muscle fascia tissue were prepared for microscope observation. The chosen method of preparation allows for the long-term preservation of the tissue samples for future studies. Capillary bundles are photographed under a microscope with 40x magnification. From the images, the microvasculature of the tissue samples is reconstructed. It was found, for example, that the distribution of vessel length in a capillary bundle follows a log-normal law. In addition to a statistical analysis of the vessel data, the network topology is used for numerical simulations of the flow in the capillary bundles. The numerical approach uses a sparse-matrix solver and it considers vessel elasticity and blood rheology. The numerical simulations show, for example, a strong pressure drop across the capillary vessels of the bundle.

  12. Carboxyl modified magnetic nanoparticles coated open tubular column for capillary electrochromatographic separation of biomolecules.

    Science.gov (United States)

    Wang, Wentao; Xiao, Xing; Chen, Jia; Jia, Li

    2015-09-11

    Carboxyl modified magnetic nanoparticles (Fe3O4-COOH MNPs) coated open tubular (OT) columns were prepared for capillary electrochromatography. The Fe3O4-COOH MNPs coatings were constructed on the surface of positively charged poly(diallydimethylammonium chloride) (PDDA) modified capillaries through electrostatic self-assembly approach. The as-prepared PDDA@Fe3O4-COOH MNPs coated OT columns were characterized by scanning electron microscopy and electroosmotic flow measurement. The electrochromatographic characterization of the OT columns was evaluated by separation of amino acids, dipeptides and proteins. The influences of background solution pH, concentration, and organic modifier content on separation were investigated. The separation of these analytes was primarily based on the electrophoretic mechanism in combination with chromatographic mechanism. The Fe3O4-COOH MNPs coatings improved the separation resolution of these analytes due to their large surface area. Three variants of bovine serum albumin, two variants of β-lactoglobulin and nine glycoisoforms of ovalbumin were successfully separated. The relative standard deviations of migration times of analytes representing run-to-run, day-to-day and column-to-column were less than 4.3%. Furthermore, the feasibility of the PDDA@Fe3O4-COOH MNPs coated OT column was verified by successful separation of acidic proteins in egg white. PMID:26265004

  13. Capillary electrophoresis separation of neutral organic compounds, pharmaceutical drugs, proteins and peptides, enantiomers, and anions

    Energy Technology Data Exchange (ETDEWEB)

    Ding, W.L.

    1999-02-12

    Addition of a novel anionic surfactant, namely lauryl polyoxyethylene sulfate, to an aqueous-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the association between analytes and the surfactant. Highly hydrophobic compounds such as polyaromatic hydrocarbons are well separated by this new surfactant. Migration times of analytes can be readily changed over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. Several examples are given, including the separation of four methylbenz[a]anthracene isomers and the separation of normal and deuterated acetophenone. The effect of adding this new surfactant to the acidic electrolyte was also investigated. Incorporation of cetyltrimethylammonium bromide in the electrolyte is shown to dynamically coat the capillary and reverse electroosmotic flow. Chiral recognition mechanism is studied using novel synthetic surfactants as chiral selectors, which are made from amino acids reacting with alkyl chloroformates. A satisfactory separation of both inorganic and organic anions is obtained using electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. The effect of various salts on electrophoretic and electroosmotic mobility is further discussed. Several examples are given under high-salt conditions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yufeng (BATTELLE (PACIFIC NW LAB)); Tolic, Nikola (BATTELLE (PACIFIC NW LAB)); Zhao, Rui (ASSOC WESTERN UNIVERSITY); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)); Li, Lingjun (Illinois Univ Of-Urbana/Champa); Berger, Scott J.(ASSOC WESTERN UNIVERSITY); Harkewicz, Richard (BATTELLE (PACIFIC NW LAB)); Anderson, Gordon A.(BATTELLE (PACIFIC NW LAB)); Belov, Mikhail E.(BATTELLE (PACIFIC NW LAB)); Smith, Richard D.(BATTELLE (PACIFIC NW LAB))

    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.

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

    Science.gov (United States)

    Williams, George O., Jr.

    1996-01-01

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

  16. Efficient computation of capillary-gravity generalized solitary waves

    CERN Document Server

    Dutykh, Denys; Duran, Angel

    2015-01-01

    This paper is devoted to the computation of capillary-gravity solitary waves of the irrotational incompressible Euler equations with free surface. The numerical study is a continuation of a previous work in several points: an alternative formulation of the Babenko-type equation for the wave profiles, a detailed description of both the numerical resolution and the analysis of the internal flow structure under a solitary wave. The numerical code used in this study is provided in open source for interested readers.

  17. Sialic acid accelerates the electrophoretic velocity of injured dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Chen-xu Li; Guo-ying Ma; Min-fang Guo; Ying Liu

    2015-01-01

    Peripheral nerve injury has been shown to result in ectopic spontaneous discharges on soma and injured sites of sensory neurons, thereby inducing neuropathic pain. With the increase of membrane proteins on soma and injured site neurons, the negatively charged sialic acids bind to the external domains of membrane proteins, resulting in an increase of this charge. We therefore speculate that the electrophoretic velocity of injured neurons may be faster than non-injured neurons. The present study established rat models of neuropathic pain via chronic constriction injury. Results of the cell electrophoresis test revealed that the electrophoretic velocity of injured neuronal cells was faster than that of non-injured (control) cells. We then treated cells with di-valent cations of Ca2+and organic compounds with positive charges, polylysine to counteract the negatively charged sialic acids, or neuraminidase to speciifcally remove sialic acids from the membrane surface of injured neurons. All three treatments significantly reduced the electro-phoretic velocity of injured neuronal cells. These ifndings suggest that enhanced sialic acids on injured neurons may accelerate the electrophoretic velocity of injured neurons.

  18. Electrophoretic deposition of metal nanoparticle monolayers from nonpolar solvents for hydrogen sensing

    OpenAIRE

    Grym, J.; Yatskiv, R. (Roman); Černohorský, O. (Ondřej); Verde, M.; Lorinčík, J. (Jan); Pham, V. H.; Gebre, T.; Dickerson, J.H.

    2015-01-01

    We report on the electrophoretic deposition (EPD) of metal nanoparticles (NPs) prepared in reverse micelles on semiconductor substrates with the aim to fabricate sensitive Schottky-based hydrogen sensors with fast response and high degree of selectivity. We discuss the mechanism of NP monolayer formation and show which parameters are essential for the transition from threedimensional to two-dimensional growth

  19. Sialic acid accelerates the electrophoretic velocity of injured dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Chen-xu Li

    2015-01-01

    Full Text Available Peripheral nerve injury has been shown to result in ectopic spontaneous discharges on soma and injured sites of sensory neurons, thereby inducing neuropathic pain. With the increase of membrane proteins on soma and injured site neurons, the negatively charged sialic acids bind to the external domains of membrane proteins, resulting in an increase of this charge. We therefore speculate that the electrophoretic velocity of injured neurons may be faster than non-injured neurons. The present study established rat models of neuropathic pain via chronic constriction injury. Results of the cell electrophoresis test revealed that the electrophoretic velocity of injured neuronal cells was faster than that of non-injured (control cells. We then treated cells with divalent cations of Ca 2+ and organic compounds with positive charges, polylysine to counteract the negatively charged sialic acids, or neuraminidase to specifically remove sialic acids from the membrane surface of injured neurons. All three treatments significantly reduced the electrophoretic velocity of injured neuronal cells. These findings suggest that enhanced sialic acids on injured neurons may accelerate the electrophoretic velocity of injured neurons.

  20. Comparison of chemical, electrophoretic and in vitro digestion methods for predicting fish meal nutritive quality

    DEFF Research Database (Denmark)

    Bassompierre, M.; Larsen, K.L.; Zimmermann, W.;

    1998-01-01

    Chemical, electrophoretic and in vitro digestion methods were compared with respect to predictions given regarding fish meal (FM) quality. FMs were manufactured by mixing a press-cake, with spray dried stickwater concentrate from the identical raw material, thereby providing samples containing...