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Sample records for capillary electrophoretic analysis

  1. Capillary electrophoretic and mass spectrometric analysis of a polydisperse fluorosurfactant.

    Science.gov (United States)

    Al-Jarah, Suhair Yousif; Sjödahl, Johan; Woldegiorgis, Andreas; Emmer, Asa

    2005-02-01

    A fluorosurfactant has been studied using capillary electrophoresis and mass spectrometry. The fluorosurfactant, FC134, can be used as a buffer additive in capillary electrophoresis in order to decrease wall adsorption of proteins and in micellar electrokinetic chromatography. However, it has been discovered that this fluorosurfactant is polydisperse, thus containing substances with different lengths and structures. In this work, the fluorosurfactant sample components were separated by capillary electrophoresis. An uncoated as well as a poly(vinyl alcohol)-coated capillary were used with running electrolytes containing methanol and acetic acid. Following the capillary electrophoretic separation, fractions were collected for further analysis by MALDI-MS. Non-fractionated samples were also analyzed both by MALDI-MS and by ESI-MS.

  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 ANALYSIS OF LOW-MOLECULAR-MASS OF CA SPECIES IN PHLOEM SAP OF Ricinus communis L.

    OpenAIRE

    Fitri, Noor; Thiele, Björn; Günther, Klaus; Buchari, Buchari

    2010-01-01

    A capillary electrophoretic (CE) analysis with ultra-violet (UV) detection was performed for further separation of low-molecular-mass (LMM) calcium species in phloem sap of Ricinus communis L. Two different background electrolytes (BGE) were used for the separation; these are (1) hydrogen phosphate/dihydrogen phosphate buffer containing cetyltrimethylammonium bromide (CTAB) as an electro-osmotic flow (EOF) modifier, and (2) boric acid buffer containing CTAB. Various parameters affecting the a...

  4. CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS

    Science.gov (United States)

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

  5. Analysis of urinary drugs of abuse by a multianalyte capillary electrophoretic immunoassay.

    Science.gov (United States)

    Caslavska, J; Allemann, D; Thormann, W

    1999-04-09

    This paper characterizes a novel multianalyte competitive binding, electrokinetic capillary-based immunoassay for urinary methadone, opiates, benzoylecgonine (cocaine metabolite) and amphetamines. After incubation of 25 microliters urine with the reactants for several minutes in the presence of an internal standard, a small aliquot of the mixture is applied onto a fused-silica capillary and the unbound fluorescein labelled drug tracers are monitored by capillary electrophoresis with on-column laser induced fluorescence detection. The multianalyte assay is shown to be rapid, simple, quantitative, capable of recognizing urinary drug concentrations > or = 30 ng/ml and suitable for screening of patient urines. Data are demonstrated to compare well with those obtained by routine screening methods based on enzyme multiplied immunoassay techniques and fluorescence polarization immunoassays. The electrokinetic capillary assay has been validated via analysis of external quality control urines and confirmation analysis of patient urines using GC-MS.

  6. Electrophoretic analysis of biomarkers using capillary modification with gold nanoparticles embedded in a polycation and boron doped diamond electrode.

    Science.gov (United States)

    Zhou, Lin; Glennon, Jeremy D; Luong, John H T

    2010-08-15

    Field-amplified sample stacking using a fused silica capillary coated with gold nanoparticles (AuNPs) embedded in poly(diallyl dimethylammonium) chloride (PDDA) has been investigated for the electrophoretic separation of indoxyl sulfate, homovanillic acid (HVA), and vanillylmandelic acid (VMA). AuNPs (27 nm) exhibit ionic and hydrophobic interactions, as well as hydrogen bonding with the PDDA network to form a stable layer on the internal wall of the capillary. This approach reverses electro-osmotic flow allowing for fast migration of the analytes while retarding other endogenous compounds including ascorbic acid, uric acid, catecholamines, and indoleamines. Notably, the two closely related biomarkers of clinical significance, HVA and VMA, displayed differential interaction with PDDA-AuNPs which enabled the separation of this pair. The detection limit of the three analytes obtained by using a boron doped diamond electrode was approximately 75 nM, which was significantly below their normal physiological levels in biological fluids. This combined separation and detection scheme was applied to the direct analysis of these analytes and other interfering chemicals including uric and ascorbic acids in urine samples without off-line sample treatment or preconcentration.

  7. Capillary electrophoretic analysis of flavonoids in single-styled hawthorn (Crataegus monogyna Jacq.) ethanolic extracts.

    Science.gov (United States)

    Urbonaviciūte, A; Jakstas, V; Kornysova, O; Janulis, V; Maruska, A

    2006-04-21

    Flavonoids are an important group of natural compounds, which can prevent coronary heart disease and have antioxidant properties. Hawthorn is a well known and widely used medicinal plant due to its cardiotonic activity. Previous studies refer mostly to the HPLC analysis of the flavonoids: vitexin, quercetin, hyperoside, oligomeric procyanidins, which appear to be primarily responsible for the cardiac action of the plant. Aqueous ethanolic extracts of single-styled hawthorn (Crataegus monogyna Jacq., f.: Rosaceae Juss.) leaves and sprouts were analyzed by means of capillary zone electrophoresis (CZE). Influence of vegetation period on the extract qualitative composition and flavonoids quantities was evaluated. Sample preparation by extraction using different concentration of aqueous ethanol (40-96%, v/v) and the influence of extractant composition on the recovery of flavonoids are discussed in detail. The results obtained using CZE are compared to the results of spectrophotometric and HPLC analysis of the extracts. The effect of storage conditions of extracts (solar irradiation, temperature and duration) on degradation of flavonoids was investigated.

  8. Capillary electrophoretic behavior of seven sulfonylureas.

    Science.gov (United States)

    Matchett, W H; Winnik, W; Brumley, W C

    1996-01-01

    The electrophoretic behavior of seven sulfonylureas (bensulfuron methyl, sulfometuron methyl, nicosulfuron [accent], chlorimuron ethyl, thifensulfuron methyl [harmony], metsulfuron methyl, and chlorsulfuron) was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditions. Mixtures of these compounds were separated with very high efficiencies (2 x 10(5) theoretical plates) in a running buffer consisting of 3 parts acetate buffer (25 mM, pH 5.0) and 1 part acetonitrile. In this buffer system, acetonitrile was shown to be superior to methanol, acetone, and ethanol as a nonpolar additive, but any of these solvents can be used to reduce electroosmotic flow (EOF) and to obtain adequate separation. On-column detection limits at 214 nM were of the order of 80-100 fM. Micellar agents such as sodium dodecyl sulfate (SDS) and sodium cholate (but not monosialoganglioside-Gm1 or starburst dendrimer, generation 2.5) improved separation in phosphate and borate buffers. Implications of these results for the development of methods to detect these compounds on matrices of environmental origin are discussed. In particular, the instability of these compounds in methanol is noted and degradation products are detected using free zone CE. The methanolysis products of sulfometuron are tentatively identified by tandem MS (negative ion conditions) as 2-amino-4,6-dimethylpyrimidine and 2-carboxymethylbenz(N-carboxymethyl)sulfonamide.

  9. Capillary electrophoresis, gas-phase electrophoretic mobility molecular analysis, and electron microscopy: effective tools for quality assessment and basic rhinovirus research.

    Science.gov (United States)

    Weiss, Victor U; Subirats, Xavier; Kumar, Mohit; Harutyunyan, Shushan; Gösler, Irene; Kowalski, Heinrich; Blaas, Dieter

    2015-01-01

    We describe standard methods for propagation, purification, quality control, and physicochemical characterization of human rhinoviruses, using HRV-A2 as an example. Virus is propagated in HeLa-OHIO cells grown in suspension culture and purified via sucrose density gradient centrifugation. Purity and homogeneity of the preparations are assessed with SDS-polyacrylamide gel electrophoresis (SDS-PAGE), capillary electrophoresis (CE), gas-phase electrophoretic mobility molecular analysis (GEMMA), and electron microscopy (EM). We also briefly describe usage of these methods for the characterization of subviral particles as well as for the analysis of their complexes with antibodies and soluble recombinant receptor mimics.

  10. 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.

  11. 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.

  12. Characterization of rhinovirus subviral A particles via capillary electrophoresis, electron microscopy and gas-phase electrophoretic mobility molecular analysis: Part I.

    Science.gov (United States)

    Weiss, Victor U; Subirats, Xavier; Pickl-Herk, Angela; Bilek, Gerhard; Winkler, Wolfgang; Kumar, Mohit; Allmaier, Günter; Blaas, Dieter; Kenndler, Ernst

    2012-07-01

    During infection, enteroviruses, such as human rhinoviruses (HRVs), convert from the native, infective form with a sedimentation coefficient of 150S to empty subviral particles sedimenting at 80S (B particles). B particles lack viral capsid protein 4 (VP4) and the single-stranded RNA genome. On the way to this end stage, a metastable intermediate particle is observed in the cell early after infection. This subviral A particle still contains the RNA but lacks VP4 and sediments at 135S. Native (150S) HRV serotype 2 (HRV2) as well as its empty (80S) capsid have been well characterized by capillary electrophoresis. In the present paper, we demonstrate separation of at least two forms of subviral A particles on the midway between native virions and empty 80S capsids by CE. For one of these intermediates, we established a reproducible way for its preparation and characterized this particle in terms of its electrophoretic mobility and its appearance in transmission electron microscopy (TEM). Furthermore, the conversion of this intermediate to 80S particles was investigated. Gas-phase electrophoretic mobility molecular analysis (GEMMA) yielded additional insights into sample composition. More data on particle characterization including its protein composition and RNA content (for unambiguous identification of the detected intermediate as subviral A particle) will be presented in the second part of the publication.

  13. On-capillary sample cleanup method for the electrophoretic determination of carbohydrates in juice samples.

    Science.gov (United States)

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

    2007-05-01

    On many occasions, sample treatment is a critical step in electrophoretic analysis. As an alternative to batch procedures, in this work, a new strategy is presented with a view to develop an on-capillary sample cleanup method. This strategy is based on the partial filling of the capillary with carboxylated single-walled carbon nanotube (c-SWNT). The nanoparticles retain interferences from the matrix allowing the determination and quantification of carbohydrates (viz glucose, maltose and fructose). The precision of the method for the analysis of real samples ranged from 5.3 to 6.4%. The proposed method was compared with a method based on a batch filtration of the juice sample through diatomaceous earth and further electrophoretic determination. This method was also validated in this work. The RSD for this other method ranged from 5.1 to 6%. The results obtained by both methods were statistically comparable demonstrating the accuracy of the proposed methods and their effectiveness. Electrophoretic separation of carbohydrates was achieved using 200 mM borate solution as a buffer at pH 9.5 and applying 15 kV. During separation, the capillary temperature was kept constant at 40 degrees C. For the on-capillary cleanup method, a solution containing 50 mg/L of c-SWNTs prepared in 300 mM borate solution at pH 9.5 was introduced for 60 s into the capillary just before sample introduction. For the electrophoretic analysis of samples cleaned in batch with diatomaceous earth, it is also recommended to introduce into the capillary, just before the sample, a 300 mM borate solution as it enhances the sensitivity and electrophoretic resolution.

  14. Characterization of rhinovirus subviral A particles via capillary electrophoresis, electron microscopy and gas phase electrophoretic mobility molecular analysis: part II.

    Science.gov (United States)

    Subirats, Xavier; Weiss, Victor U; Gösler, Irene; Puls, Christoph; Limbeck, Andreas; Allmaier, Günter; Kenndler, Ernst

    2013-06-01

    Human rhinoviruses (HRVs) are valuable tools in the investigation of early viral infection steps due to their far reaching (although still incomplete) characterization. During endocytosis, native virions first loose one of the four capsid proteins (VP4); corresponding particles sediment at 135S and were termed subviral A particles. Subsequently, the viral RNA genome leaves the viral shell giving rise to empty capsids. In continuation of our previous work with HRV serotype 2 (HRV2) intermediate subviral particles, in which we were able to discriminate by CE even between two intermediates (AI and AII) of virus uncoating, we further concentrated on the characterization of AI particles with the electrophoretic mobility of around -17.2 × 10(-9) m(2) /Vs at 20°C. In the course of our present work we related these particles to virions as previously described at the subviral A stage of uncoating (and as such sedimenting at 135S) by determination of their protein and RNA content--in comparison to native virions AI particles did not include VP4, however, still 93% of their initial RNA content. Binding of an mAb specific for subviral particles demonstrated antigenic rearrangements on the capsid surface at the AI stage. Furthermore, we investigated possible factors stabilizing intermediates of virus uncoating. We could exclude the influence of the previously suspected so-called contaminant of virus preparation on HRV2 subviral particle formation. Instead, we regarded other factors being part of the virus preparation system and found a dependence of AI particle formation on the presence of divalent cations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Gordaliza, Estefanía, E-mail: emorenog@ucm.es [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Analytical Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040, Madrid (Spain); Stigter, Edwin C.A. [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Molecular Cancer Research, Universitair Medisch Centrum Utrecht, Wilhelmina Kinder Ziekenhuis, Lundlaan 6, 3584, EA Utrecht (Netherlands); Lindenburg, Petrus W.; Hankemeier, Thomas [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands)

    2016-06-07

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

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

    OpenAIRE

    Árpád Gyéresi; Eleonora Mircia; Brigitta Simon; Aura Rusu; Gabriel Hancu

    2013-01-01

    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...

  17. 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 at...

  18. Development of a Capillary Zone Electrophoretic Method for the Rapid Separation and Detection of Hepatotoxic Microcystins

    Energy Technology Data Exchange (ETDEWEB)

    Li, Paul C.H.; Hu, Shen; Lam, Paul K.S

    1999-01-01

    Analysis of trace amounts of various hepatotoxic microcystins in marine and freshwater samples is very important since these toxins, especially microcystin-LR, have been demonstrated to have tumour-promoting activity. In this study, instead of measuring the total amount of microcystins, we developed a capillary zone electrophoretic method for the separation and detection of individual toxin standards. No additives were used for enhancement of resolution. This technique is characterized by a high separation efficiency, short analysis time and small sample volume. In order to improve the detection sensitivity, a laser-induced fluorescence detector was used, and the labelling of microcystins was accomplished through a two-step procedure. First, the microcystin standards were converted into cysteine conjugates, followed by derivatization with Fluorescein 5-Isothiocyanate (FITC). After derivatization, the FITC-labelled microcystins were directly injected, separated and detected in 8 min. This method was shown to be a promising technique for sensitive and rapid analysis of individual microcystin toxins.

  19. Use of gemini surfactants as semipermanent capillary coatings in aqueous-organic solvents for capillary electrophoretic separation of inorganic anions.

    Science.gov (United States)

    Liu, Qian; Li, Yanqing; Yao, Lihua; Yao, Shouzhuo

    2009-12-01

    This paper proposes a new method for CE separation of inorganic anions based on the use of gemini surfactants as capillary coatings in mixed aqueous-organic solvents. The semipermanent gemini surfactant coatings were facilely prepared by rinsing the capillary with 18-s-18 solutions; they can keep be stable during the electrophoretic runs without surfactants in buffer. The coatings showed a good tolerance of methanol (MeOH) or ACN, e.g. at pH 8.0 and with 40% v/v MeOH or ACN, the EOF magnitude after 60 min of continuous electrokinetic rinsing only decreased by 2.9 or 6.0%, respectively. The coatings were successfully applied to the separation of inorganic anions. Adding organic solvents in buffer can effectively improve the resolution and efficiencies; however, it remarkably prolonged the analysis time due to the suppression of EOF. Interestingly, varying the spacer length of the gemini surfactants can also modulate (improve) the resolution but without any sacrifice of analysis time. This benefit was resulted from the unique chemical structures of gemini surfactants because it introduced a new variable, i.e. the spacer length, to the separation mechanism.

  20. 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).

  1. 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.

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

    Science.gov (United States)

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

    2011-06-01

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

  3. Capillary electrophoretic study of green fluorescent hollow carbon nanoparticles.

    Science.gov (United States)

    Liu, Lizhen; Feng, Feng; Hu, Qin; Paau, Man Chin; Liu, Yang; Chen, Zezhong; Bai, Yunfeng; Guo, Fangfang; Choi, Martin M F

    2015-09-01

    CE coupled with laser-induced fluorescence and UV absorption detections has been applied to study the complexity of as-synthesized green fluorescent hollow carbon nanoparticles (HC-NP) samples. The effects of pH, type, and concentration of the run buffer and SDS on the separation of HC-NP are studied in detail. It is observed that phosphate run buffer is more effective in separating the HC-NP and the optimal run buffer is found to be 30 mM phosphate and 10 mM SDS at pH 9.0. The CE separation of this HC-NP is based on the difference in size and electrophoretic mobility of HC-NP. Some selected HC-NP fractions are collected and further characterized by UV-visible absorption and photoluminescence (PL) spectroscopy, MS, and transmission electron microscopy. The fractionated HC-NP show profound differences in absorption, emission characteristics, and PL quantum yield that would have been otherwise misled by studying the complex mixture alone. It is anticipated that our CE methodology will open a new initiative on extensive studies of individual HC-NP species in the biomedical, catalysis, electronic, and optical device, energy storage, material, and sensing field.

  4. 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.

  5. Principles of micellar electrokinetic capillary chromatography applied in pharmaceutical analysis.

    Science.gov (United States)

    Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Arpád

    2013-01-01

    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.

  6. 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.

  7. 21 CFR 864.7440 - Electrophoretic hemoglobin analysis system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrophoretic hemoglobin analysis system. 864....7440 Electrophoretic hemoglobin analysis system. (a) Identification. An electrophoretic hemoglobin... hemoglobin types as an aid in the diagnosis of anemia or erythrocytosis (increased total red cell mass)...

  8. Capillary Electrophoresis in the Analysis of Polyunsaturated Fatty Acids

    Directory of Open Access Journals (Sweden)

    Gabriel Hancu

    2015-12-01

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

  9. 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.

  10. Electrophoretic behavior of charge regulated zwitter ionic buffers in covalently and dynamically coated fused silica capillaries

    Directory of Open Access Journals (Sweden)

    Medhat A. Al-Ghobashy

    2014-06-01

    Full Text Available In this work, the electrophoretic behavior of zwitterionic buffers is investigated in the absence of electroosmotic flow (EOF. Electro mobilization of capillary contents is noted when zwitterionic buffers are employed as the background electrolyte at a pH where the buffering moiety carries a net charge. The bulk flow of capillary contents was demonstrated via monitoring the migration of a neutral marker as well as a free and micellar negatively charged marker and SDS–protein complexes. This electrolyte-driven mobilization (EDM was investigated in detail using 4-(2-hydroxyethylpiprazine-1-ethanesulfonic acid (HEPES buffer over a wide pH range (pH 4.0–8.0. Results confirmed that at a pH where HEPES molecules carry a net negative charge, a bulk flow toward the anode is observed. This was attributed to the migration of HEPES ions toward the anode along with their hydration shells. The relatively large difference in size and solvation number between the ionic buffering moiety and its counter-migrating ions (Na+ or H+ resulted in such a net movement. Results indicated that at constant voltage, plotting the measured current versus buffer pH can be used for determination of the isoelectric point of the zwitterionic buffering moiety. Furthermore, this novel mobilization modality was demonstrated using five different HEPES analogs over pH range 5.0–8.0. More in depth investigations are required in order to explore the applicability of EDM in coated capillaries of different wall chemistries and dimensions.

  11. Separation and analysis of triazine herbcide residues by capillary electrophoresis.

    Science.gov (United States)

    Elbashir, Abdalla A; Aboul-Enein, Hassan Y

    2015-06-01

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

  12. Capillary electrophoretic determination of main components of natural dyes with MS detection.

    Science.gov (United States)

    Surowiec, Izabella; Pawelec, Katarzyna; Rezeli, Melinda; Kilar, Ferenc; Trojanowicz, Marek

    2008-07-01

    CE with UV-Vis and MS detections was investigated as a technique for detection of main components of selected natural dyes of plant and insect origin. The BGE giving the best separation of the investigated flavonoids and anthraquinoids, suitable for MS detection consisted of 40 mM ammonium acetate solution of pH 9.5 with 40% ACN. LODs obtained with MS detection were even one order of magnitude lower than the ones obtained with UV-Vis detection. Application of MS detection enabled determination of eleven dye compounds from three different chemical groups in 15 min. and proved to be more satisfactory than diode-array detection in the electrophoretic analysis of main classes of natural dyes both in terms of selectivity and sensitivity of analysis.

  13. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Andrea Ming-Wei [Iowa State Univ., Ames, IA (United States)

    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.

  15. 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.

  16. Characterization of Dickeya and Pectobacterium species by capillary electrophoretic techniques and MALDI-TOF MS.

    Science.gov (United States)

    Šalplachta, Jiří; Kubesová, Anna; Horký, Jaroslav; Matoušková, Hana; Tesařová, Marie; Horká, Marie

    2015-10-01

    Dickeya and Pectobacterium species represent an important group of broad-host-range phytopathogens responsible for blackleg and soft rot diseases on numerous plants including many economically important plants. Although these species are commonly detected using cultural, serological, and molecular methods, these methods are sometimes insufficient to classify the bacteria correctly. On that account, this study was undertaken to investigate the feasibility of three individual analytical techniques, capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), for reliable classification of Dickeya and Pectobacterium species. Forty-three strains, representing different Dickeya and Pectobacterium species, namely Dickeya dianthicola, Dickeya dadantii, Dickeya dieffenbachiae, Dickeya chrysanthemi, Dickeya zeae, Dickeya paradisiaca, Dickeya solani, Pectobacterium carotovorum, and Pectobacterium atrosepticum, were selected for this purpose. Furthermore, the selected bacteria included one strain which could not be classified using traditional microbiological methods. Characterization of the bacteria was based on different pI values (CIEF), migration velocities (CZE), or specific mass fingerprints (MALDI-TOF MS) of intact cells. All the examined strains, including the undetermined bacterium, were characterized and classified correctly into respective species. MALDI-TOF MS provided the most reliable results in this respect.

  17. Electrophoretic concentration and sweeping-micellar electrokinetic chromatography analysis of cationic drugs in water samples.

    Science.gov (United States)

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

    2015-07-03

    Sample preparation by electrophoretic concentration, followed by analysis using sweeping-micellar electrokinetic chromatography, was studied as a green and simple analytical strategy for the trace analysis of cationic drugs in water samples. Electrophoretic concentration was conducted using 50 mmol/L ammonium acetate at pH 5 as acceptor electrolyte. Electrophoretic concentration was performed at 1.0 kV for 50 min and 0.5 kV and 15 min for purified and 10-fold diluted waste water samples, respectively. Sweeping-micellar electrokinetic chromatography was with 100 mmol/L sodium phosphate at pH 2, 100 mmol/L sodium dodecyl sulfate and 27.5%-v/v acetonitrile as separation electrolyte. The separation voltage was -20 kV, UV-detection was at 200 nm, and the acidified concentrate was injected for 36 s at 1 bar (or 72% of the total capillary length, 60 cm). Both purified water and 10-fold diluted waste water exhibited a linear range of two orders of concentration magnitude. The coefficient of determination, and intra- and interday repeatability were 0.991-0.997, 2.5-6.2, and 4.4-9.7%RSD (n=6), respectively, for purified water. The values were 0.991-0.997, 3.4-7.1, and 8.7-9.8%RSD (n=6), correspondingly, for 10-fold diluted waste water. The method detection limit was in the range from 0.04-0.09 to 1.20-6.97 ng/mL for purified and undiluted waste water, respectively.

  18. 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.

  19. Screening for urinary amphetamine and analogs by capillary electrophoretic immunoassays and confirmation by capillary electrophoresis with on-column multiwavelength absorbance detection.

    Science.gov (United States)

    Ramseier, A; Caslavska, J; Thormann, W

    1998-11-01

    This paper characterizes competitive binding, electrokinetic capillary-based immunoassays for screening of urinary amphetamine (A) and analogs using reagents which were commercialized for a fluorescence polarization immunoassay (FPIA). After incubation of 25 microL urine with the reactants, a small aliquot of the mixture is applied onto a fused-silica capillary and unbound fluorescein-labeled tracer compounds are monitored by capillary electrophoresis with on-column laser-induced fluorescence detection. Configurations in presence and absence of micelles were investigated and found to be capable of recognizing urinary D-(+)-amphetamine at concentrations > about 80 ng/mL. Similar responses were obtained for racemic methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA). The electrokinetic immunoassay data suggest that the FPIA reagent kit includes two immunoassay systems (two antibodies and two tracer molecules), one that recognizes MA and MDMA, and one that is geared towards monitoring of A. For confirmation analysis of urinary amphetamines and ephedrines, capillary electrophoresis in a pH 9.2 buffer and multiwavelength UV detection was employed. The suitability of the electrokinetic methods for screening and confirmation is demonstrated via analysis of patient and external quality control urines.

  20. 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.

  1. 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.

  2. ESI-MS compatible permanent coating of glass surfaces using poly(ethylene glycol)-terminated alkoxysilanes for capillary zone electrophoretic protein separations.

    Science.gov (United States)

    Razunguzwa, Trust T; Warrier, Manoj; Timperman, Aaron T

    2006-07-01

    Thin poly(ethylene glycol) silane (PEG-silane) coatings formed from N-(triethoxysilyl propyl)-O-poly(ethylene oxide) urethane with different chain lengths of poly(ethylene glycol) (MW 750 and 4000-5000) are used to modify glass microfluidic channels and fused-silica capillaries for electrophoretic separations of proteins. These coatings combine three important properties, which make them favorable for proteomic analyses including reduction of protein adsorption, compatibility with mass spectrometry due to their stability, and the ability to control the magnitude of electroosmotic flow (EOF). The coatings have been successfully used in microfluidic chips and fused-silica capillaries for separation of protein sample mixtures under low EOF conditions. The long-chain and mixed PEG-silane coatings suppress electroosmotic flow by more than 90%, whereas the short-chain PEG silane suppresses EOF by 65-75% at pH values of 3-9. The long-chain and mixed PEG-silane coatings are suitable for low EOF applications or for cases where negative effects of EOF are to be minimized. Efficient separations of unlabeled basic proteins at low pH and FITC-labeled proteins at high pH were achieved, as well as excellent stability for at least 200 electrophoretic runs. Additionally, these covalent coatings produce no detectable background ions in ESI-MS, making them compatible with on-line mass spectrometry.

  3. Chromatographic and electrophoretic methods for nanodisc purification and analysis

    DEFF Research Database (Denmark)

    Justesen, Bo Højen; Günther-Pomorski, Thomas

    2014-01-01

    Soluble nanoscale lipid bilayers, termed nanodiscs, are widely used in science for studying the membrane-anchored and integral membrane protein complexes under defined experimental conditions. Although their formation occurs by a self-assembly process, nanodisc purification and the verification...... 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....

  4. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    Science.gov (United States)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  5. 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.

  6. 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.

  7. Use of beta-cyclodextrin in the capillary zone electrophoretic separation of the components of clandestine heroin preparations.

    Science.gov (United States)

    Macchia, M; Manetto, G; Mori, C; Papi, C; Di Pietro, N; Salotti, V; Bortolotti, F; Tagliaro, F

    2001-07-27

    The present paper describes the methodological optimization and validation of a capillary zone electrophoresis method for the rapid determination of heroin, secondary products and additives present in clandestine heroin samples, by using 20 mM beta-cyclodextrins in phosphate buffer, pH 3.23. Applied potential was 15 kV and separation temperature was 24 degrees C; detection was by UV absorption at 200 nm wavelength. Heroin samples were first dissolved in CHCl3-MeOH (96:4, v/v) and injected by pressure (0.5 p.s.i., 3 s; 1 p.s.i.=6894.76 Pa) after evaporation of the organic mixture and reconstitution in aqueous buffer. Under the described conditions, phenylethylamine (internal standard), morphine, monoacetylmorphine, heroin, acetylcodeine, papaverine, codeine and narcotine were baseline resolved in less than 10 min. The limit of detection was better than 1 microg/ml for each analyte. The study of the intra-day and day-to-day precision showed, in terms of migration times, RSDs < or = 0.71% and, in terms of peak areas, RSDs < or = 3.2%. Also, the evaluation of linearity and analytical accuracy of the method provided good results for all the analytes investigated, thus allowing its application to real cases of seized controlled drug preparations.

  8. Electrophoretic analysis of seed storage proteins from gymnosperms.

    Science.gov (United States)

    Allona, I; Collada, C; Casado, R; Aragoncillo, C

    1994-01-01

    Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pore gradient gel electrophoresis (PGGE) followed by SDS-PAGE and Western blot analysis were used to characterize the seed storage proteins from seven gymnosperm species from the families Pinaceae (Abies alba, Cedrus atlantica and Picea abies), Cupressaceae (Biota orientalis, Chamaecyparis lawsoniana and Cupressus arizonica), and Taxaceae (Taxus baccata). SDS-PAGE and PGGE X SDS-PAGE indicate the presence of proteins with characteristics similar to the 7S globulins in all the species studied. Antibodies to a 7S globulin subunit from Pinus pinaster cross-reacted with homologous polypeptides from Pinaceae species, but not with corresponding subunits from species belonging to other families. Also detected in each of the studied species, with the exception of A. alba and T. baccata, were those of C. atlantica may be extracted by saline buffer, while the remainder require a dissociating agent. Antibodies raised against the small subunit from P. pinaster 11S protein recognized only the corresponding polypeptides from Pinaceae species. Overall, these results help clarify our knowledge of gymnosperm seed storage proteins.

  9. Development and validation of a stability-indicating capillary zone electrophoretic method for the assessment of entecavir and its correlation with liquid chromatographic methods.

    Science.gov (United States)

    Dalmora, Sergio Luiz; Nogueira, Daniele Rubert; D'Avila, Felipe Bianchini; Souto, Ricardo Bizogne; Leal, Diogo Paim

    2011-01-01

    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of entecavir in pharmaceutical formulations, using nimesulide as an internal standard. A fused-silica capillary (50 µm i.d.; effective length, 40 cm) was used while being maintained at 25°C; the applied voltage was 25 kV. A background electrolyte solution consisted of a 20 mM sodium tetraborate solution at pH 10. Injections were performed using a pressure mode at 50 mbar for 5 s, with detection at 216 nm. The specificity and stability-indicating capability were proven through forced degradation studies, evaluating also the in vitro cytotoxicity test of the degraded products. The method was linear over the concentration range of 1-200 µg mL(-1) (r(2) = 0.9999), and was applied for the analysis of entecavir in tablet dosage forms. The results were correlated to those of validated conventional and fast LC methods, showing non-significant differences (p > 0.05).

  10. 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.

  11. Gel electrophoretic methods for the analysis of biosimilar pharmaceuticals using the example of recombinant erythropoietin.

    Science.gov (United States)

    Reichel, Christian; Thevis, Mario

    2013-03-01

    Due to their versatility and cost-effectiveness, gel electrophoretic methods provide an important set of tools for the analysis of therapeutic proteins. As an increasing number of biosimilar pharmaceuticals are entering the market, techniques are required that allow reliable demonstration of comparability of these products with the reference products. Isoelectric focusing, SDS-PAGE, native PAGE and 2D electrophoresis (2D-PAGE) have been frequently applied for this purpose. Supplementary techniques are fluorophore-assisted carbohydrate electrophoresis and sarcosyl-PAGE. Of additional importance is the comparison of recombinant with endogenously synthesized glycoproteins. Reagent array analysis combined with SDS-PAGE and western blotting proved especially useful for this purpose. As an example for the application of these methods, the analysis of recombinant originator erythropoietins and some of their biosimilar counterparts is described.

  12. 20 Years of Fatty Acid Analysis by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Marcone Augusto Leal de Oliveira

    2014-09-01

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

  13. Column-coupling strategies for multidimensional electrophoretic separation techniques.

    Science.gov (United States)

    Kler, Pablo A; Sydes, Daniel; Huhn, Carolin

    2015-01-01

    Multidimensional electrophoretic separations represent one of the most common strategies for dealing with the analysis of complex samples. In recent years we have been witnessing the explosive growth of separation techniques for the analysis of complex samples in applications ranging from life sciences to industry. In this sense, electrophoretic separations offer several strategic advantages such as excellent separation efficiency, different methods with a broad range of separation mechanisms, and low liquid consumption generating less waste effluents and lower costs per analysis, among others. Despite their impressive separation efficiency, multidimensional electrophoretic separations present some drawbacks that have delayed their extensive use: the volumes of the columns, and consequently of the injected sample, are significantly smaller compared to other analytical techniques, thus the coupling interfaces between two separations components must be very efficient in terms of providing geometrical precision with low dead volume. Likewise, very sensitive detection systems are required. Additionally, in electrophoretic separation techniques, the surface properties of the columns play a fundamental role for electroosmosis as well as the unwanted adsorption of proteins or other complex biomolecules. In this sense the requirements for an efficient coupling for electrophoretic separation techniques involve several aspects related to microfluidics and physicochemical interactions of the electrolyte solutions and the solid capillary walls. It is interesting to see how these multidimensional electrophoretic separation techniques have been used jointly with different detection techniques, for intermediate detection as well as for final identification and quantification, particularly important in the case of mass spectrometry. In this work we present a critical review about the different strategies for coupling two or more electrophoretic separation techniques and the

  14. Capillary Electrophoresis Analysis of Conventional Splicing Assays

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...

  15. 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

  16. 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.

  17. 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.

  18. Effect of Joule heating on efficiency and performance for microchip-based and capillary-based electrophoretic separation systems: a closer look.

    Science.gov (United States)

    Petersen, Nickolaj J; Nikolajsen, Rikke P H; Mogensen, Klaus B; Kutter, Jörg P

    2004-01-01

    An attempt is made to revisit the main theoretical considerations concerning temperature effects ("Joule heating") in electro-driven separation systems, in particular lab-on-a-chip systems. Measurements of efficiencies in microfabricated devices under different Joule heating conditions are evaluated and compared to both theoretical models and measurements performed on conventional capillary systems. The widely accepted notion that planar microdevices are less susceptible to Joule heating effects is largely confirmed. The heat dissipation from a nonthermostatically controlled glass microdevice was found to be comparable to that from a liquid-cooled-fused silica capillary. Using typically dimensioned glass and glass/silicon microdevices, the experimental results indicate that 5-10 times higher electric field strengths can be applied than on conventional capillaries, before detrimental effects on the separation efficiency occur. The main influence of Joule heating on efficiency is via the establishment of a radial temperature profile across the lumen of the capillary or channel. An overall temperature increase of the buffer solution has only little influence on the quality of the separation. Still, active temperature control (cooling, thermostatting) can help prevent boiling of the buffer and increase the reproducibility of the results.

  19. Graphene/poly(ethylene-co-vinyl acetate) composite electrode fabricated by melt compounding for capillary electrophoretic determination of flavones in Cacumen platycladi.

    Science.gov (United States)

    Sheng, Shijun; Liu, Shuang; Zhang, Luyan; Chen, Gang

    2013-02-01

    In this report, a graphene/poly(ethylene-co-vinyl acetate) composite electrode was fabricated by melt compounding for the amperometric detection of capillary electrophoresis. The composite electrode was fabricated by packing a mixture of graphene and melted poly(ethylene-co-vinyl acetate) in a piece of fused silica capillary under heat. The structure of the composite was investigated by scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that graphene sheets were well dispersed in the composite to form an interconnected conducting network. The performance of this unique graphene-based detector has been demonstrated by separating and detecting rutin, quercitrin, kaempferol, and quercetin in Cacumen platycladi in combination with capillary electrophoresis. The four flavones have been well separated within 9 min in a 50-cm-long capillary at a separation voltage of 12 kV using a 50 mM sodium borate buffer (pH 9.2). The graphene-based detector offered significantly lower operating potentials, substantially enhanced signal-to-noise characteristics, lower expense of operation, high resistance to surface fouling, and enhanced stability. It showed long-term stability and repeatability with relative standard deviations of <5% for the peak current (n = 15).

  20. Principles, Practice, and Evolution of Capillary Electrophoresis as a Tool for Forensic DNA Analysis.

    Science.gov (United States)

    Shewale, J G; Qi, L; Calandro, L M

    2012-07-01

    Capillary electrophoresis (CE) is a versatile and widely used analysis platform with application in diverse areas such as analytical chemistry, chiral separations, clinical, forensics, molecular biology, natural products, organic chemistry, and the pharmaceutical industry. Forensic applications of CE include fragment analysis, DNA sequencing, SNP typing, and analysis of gunshot residues, explosive residues, and drugs. Fragment analysis is a widely used method for short tandem repeat (STR) profiling for human identification (HID) due to the single-base resolution capability of CE. This approach circumvents the tedious and expensive approach of DNA sequencing for STR typing. The high sizing precision, ability to detect fluorescence emitted from multiple dyes, automated electrophoretic runs, and data collection software are key factors in the worldwide adoption of CE as the preferred platform for forensic DNA analysis. The most common CE systems used in forensic DNA analysis include the ABI PRISM® 310, 3100, 3100 Avant, 3130, 3130xl, 3500, and 3500xL Genetic Analyzers (GAs). The 3500 series GAs are developed with features useful for forensic scientists, including a normalization feature for analysis of the data designed to reduce the variation in peak height from instrument to instrument and injection to injection. Other hardware and software features include improved temperature control, radio frequency identification (RFID) tags for monitoring instrument consumables, HID-focused software features, and security and maintenance.

  1. Capillary electrophoresis-mass spectrometry using noncovalently coated capillaries for the analysis of biopharmaceuticals.

    Science.gov (United States)

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

    2011-04-01

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

  2. 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

  3. 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.

  4. Electrophoretic mobility shift assays for the analysis of DNA-protein interactions.

    Science.gov (United States)

    Gaudreault, Manon; Gingras, Marie-Eve; Lessard, Maryse; Leclerc, Steeve; Guérin, Sylvain L

    2009-01-01

    Electromobility shift assay is a simple, efficient, and rapid method for the study of specific DNA-protein interactions. It relies on the reduction in the electrophoretic mobility conferred to a DNA fragment by an interacting protein. The technique is suitable to qualitative, quantitative, and kinetic analyses. It can also be used to analyze conformational changes.

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

    Science.gov (United States)

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

    2015-02-01

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

  6. 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.

  7. Analysis of recombinant human growth hormone by capillary electrophoresis with bilayer-coated capillaries using UV and MS detection.

    Science.gov (United States)

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

    2007-06-01

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

  8. 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

    2005-05-04

    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.

  9. 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.

  10. Development of a capillary electrophoresis-mass spectrometry method using polymer capillaries for metabolomic analysis of yeast.

    Science.gov (United States)

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

    2008-05-01

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

  11. Analysis of the anti-Parkinson drug pramipexole in human urine by capillary electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Musenga, Alessandro; Kenndler, Ernst; Morganti, Emanuele; Rasi, Fabrizio; Raggi, Maria Augusta

    2008-09-19

    A sensitive method based on capillary electrophoresis with laser-induced fluorescence detection has been developed for the analysis of the non-ergoline dopamine agonist pramipexole in human urine. Separation was carried out in uncoated fused silica capillaries (75microm internal diameter, 75.0 and 60.0cm total and effective length, respectively), with a background electrolyte composed of borate buffer (50mM, pH 10.3), tetrabutylammonium bromide (30mM), and acetone (15%, v/v). Applying a 20kV voltage, the electrophoretic run is completed within 12min. A sample pre-treatment procedure based on liquid/liquid extraction with ethyl acetate, followed by derivatisation of pramipexole with fluorescein isothiocyanate at pH 9, allows the complete removal of biological interferences, with extraction yields always higher than 94.5%. Method validation gave good linearity (r(2)=0.9992) in the 25.0-1000ngmL(-1) range; limit of detection and limit of quantitation were 10.0 and 25.0ngmL(-1), respectively; precision was 90.0. The method was applied to the analysis of urine samples from patients undergoing therapy with pramipexole.

  12. 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.

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

    Science.gov (United States)

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

    2016-09-01

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

  14. On-line capillary isotachophoresis-capillary zone electrophoresis analysis of bromate in drinking waters in an automated analyzer with coupled columns and photometric detection.

    Science.gov (United States)

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

    2012-12-07

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

  15. Challenges of glycoprotein analysis by microchip capillary gel electrophoresis.

    Science.gov (United States)

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

    2015-08-01

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

  16. In-capillary approach to eliminate SDS interferences in antibody analysis by capillary electrophoresis coupled to mass spectrometry.

    Science.gov (United States)

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

    2016-12-23

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

  17. 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.

  18. 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.

  19. Analysis of anions in ambient aerosols by microchip capillary electrophoresis.

    Science.gov (United States)

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

    2006-11-01

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

  20. On-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry for the analysis of large biomolecules: a preliminary report.

    Science.gov (United States)

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

    2014-08-01

    The analysis of large biomolecules by on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry (IA-SPE-CE-MS) remains unexplored because of the complex issues that need to be addressed. In this preliminary study, we used the human glycoprotein transferrin (Tf) as a model of a large biomolecule. First, we established by CE-UV a novel method compatible with IA-SPE-CE-MS, based on the use of a fused silica capillary coated with an anionic derivative of polyacrylamide (UltraTrol(TM) Dynamic Pre-Coat High Normal, HN) to prevent protein adsorption. The methodology allowed the detection of the most abundant Tf sialoforms. Repeatability studies demonstrated high stability of the coated capillaries, which was required for on-line immunoextraction and MS detection. IA-SPE-CE-UV and IA-SPE-CE-MS methods were optimized for the analysis of Tf standards and human serum samples using a laboratory-made IA sorbent. Three peaks corresponding to Tf were detected with UV detection when on-line immunoextraction was applied to the standards. The use of MS detection, however, reduced the resolution of the electrophoretic separation. Finally, we demonstrated that it was possible to detect Tf in human serum samples, after off-line serum sample de-salting by centrifugal filtration.

  1. 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.

  2. 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.

  3. Very fast capillary electrophoresis with electrochemical detection for high-throughput analysis using short, vertically aligned capillaries.

    Science.gov (United States)

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

    2014-09-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

  5. 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.

  6. 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.

  7. Particle separations by electrophoretic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ballou, N.E.; Petersen, S.L.; Ducatte, G.R.; Remcho, V.T.

    1996-03-01

    A new method for particle separations based on capillary electrophoresis has been developed and characterized. It uniquely separates particles according to their chemical nature. Separations have been demonstrated with chemically modified latex particles and with inorganic oxide and silicate particles. Separations have been shown both experimentally and theoretically to be essentially independent of particle size in the range of about 0.2 {mu}m to 10 {mu}m. The method has been applied to separations of U0{sub 2} particles from environmental particulate material. For this, an integrated method was developed for capillary electrophoretic separation, collection of separated fractions, and determinations of U0{sub 2} and environmental particles in each fraction. Experimental runs with the integrated method on mixtures of UO{sub 2} particles and environmental particulate material demonstrated enrichment factors of 20 for UO{sub 2} particles in respect to environmental particles in the U0{sub 2}containing fractions. This enrichment factor reduces the costs and time for processing particulate samples by the lexan process by a factor of about 20.

  8. 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

    2014-11-07

    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.

  9. Electrophoretic fingerprinting of benzodiazepine tablets in spike drinks.

    Science.gov (United States)

    Sáiz, Jorge; Ortega-Ojeda, Fernando; López-Melero, Lucía; Montalvo, Gema; García-Ruiz, Carmen

    2014-11-01

    Over the last few years, there has been an increase in the reports of drug-facilitated crimes. The list of drugs associated with these crimes is extensive and benzodiazepines constitute one of the groups of substances more commonly used. The sedative properties, which characterize benzodiazepines, are enhanced when such drugs are combined with alcohol, being more attractive for committing these types of crimes. In this work, a capillary electrophoresis method was applied to the analysis of 63 different samples of club drinks spiked with benzodiazepine tablets. The resulting electropherograms were processed and analyzed with the chemometric multivariate techniques: principal component analysis (PCA) and soft independent modeling of class analogies (SIMCA) classification. The PCA results allowed a clear differentiation of each drug class in a 3D plot. In addition, the SIMCA classification model (5% significance level) showed that eight out of nine test samples were automatically assigned by software to their proper sample class. The conflicting sample was correctly classified in the Coomans' plot (95% confidence). This novel approach based on the comparison of electrophoretic profiles of spiked drinks by chemometric tools allows determining the benzodiazepine used for drink spiking without the use of drug standards. Moreover, it provides an opportunity for the forensic laboratories to incorporate the identification capability provided by the electrophoretic fingerprinting of benzodiazepine solutions in existing or new databases.

  10. 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.

  11. Analysis of phenolic type antioxidants; Capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, S.K. (Indian Inst. of Petroleum, Dehradun (India)); Kapoor, V.B. (Indian Inst. of Petroleum, Dehradun (India)); Vishnoi, S.C. (Indian Inst. of Petroleum, Dehradun (India)); Bhagat, S.D. (Indian Inst. of Petroleum, Dehradun (India))

    1994-06-01

    A simple gas chromatographic (GC) procedure has been developed to estimate the individual alkylated phenols used as antioxidants to improve the shelf life of fuels and lubricants. Preparative gas chromatography was applied for separation and collection in sufficient quantity of the isomers of tertiary butyl, octyl and dodecyl phenols prepared by catalytic alkylation of phenol with isobutylene or its oligomers. The separated fractions were characterised by Infra-red spectrometry (IR) and paper chromatography. Out of several GC columns studies, a high resolution capillary column of 100% Methyl, Silicone gum (SE-30) as stationary phase gave best results. Data generated on various packed and capillary columns are in good agreement. (orig.)

  12. Analysis of Turkish lignite tar by coupled LC/GC, GC/MS, and capillary SFC

    Energy Technology Data Exchange (ETDEWEB)

    Davies, I.L.; Raynor, M.W.; Urwin, D.J.; Bartle, K.D.; Tolay, M.; Ekinci, E.; Schwartz, H.E.

    1988-11-01

    This work describes the analysis of a pyrolysis product of a lignite sample obtained from the Turkish Goynuk reserve. The aliphatic, aromatic and polar compounds present in the tar are separated and identified by various chromatographic techniques: capillary gas chromatography/mass spectrometry (GC/MS), on-line high performance microbore liquid chromatography/capillary gas chromatography (LC/GC) and capillary supercritical fluid chromatography (SFC). The suitability of each technique for this particular application is discussed, and semi-quantitative results are presented for the major components detected. 35 refs., 6 figs., 3 tabs.

  13. Analysis of electrokinetic pumping efficiency in capillary tubes.

    Science.gov (United States)

    Chein, Reiyu; Liao, Jenchen

    2007-02-01

    A mathematical model for predicting the maximum pumping efficiency and pressure difference generation by an electrokinetic-driven fluid pumping system through a capillary tube is presented in this study. Both the maximum pumping efficiency and optimum pressure difference generation are found to depend on a single variable. This single variable is termed as the figure of merit since it determines the performance of electrokinetic pumping. The figure of merit is found to depend on three dimensionless parameters, the normalized Debye length, zeta potential, and Levine number indicating the nominal ratio of convective current to conductive current. All three parameters can be related to the pH value and concentration of aqueous salt solution by the introduction of concentration-dependent electrical conductivity and pH-dependent zeta potential. By presenting the maximum pumping efficiency and optimum pressure difference generation as functions of pH value, salt concentration, and capillary tube radius, it is found that both maximum pumping efficiency and optimum pressure difference generation increase with the decrease in capillary radius and salt concentration. The optimum pH values at which the maximum pumping efficiency and optimum pressure difference generation occur are found to be in the range between 6 and 9. For the salt concentration of 10(-6) M, pH 6.9, and a capillary tube radius value of 0.5 micro m, the predicted maximum pumping efficiency is 5.4% which is close to the experimental measurement reported in the literature.

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

    Science.gov (United States)

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

    2016-01-21

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

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

    Directory of Open Access Journals (Sweden)

    Yuqing Cao

    2016-01-01

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

  16. Analysis of In Vitro DNA Interactions of Brassinosteroid-Controlled Transcription Factors Using Electrophoretic Mobility Shift Assay.

    Science.gov (United States)

    Unterholzner, Simon J; Rozhon, Wilfried; Poppenberger, Brigitte

    2017-01-01

    Most signaling cascades ultimately lead to changes in gene expression by modulating the activity of transcription factors (TFs). The electrophoretic mobility shift assay (EMSA) is a simple but powerful in vitro method for investigation of specific protein-DNA interactions. It makes use of the fact that protein-DNA complexes have a lower electrophoretic mobility in gels than free DNA has. The application of labeled probes in combination with unlabeled competitors allows investigation of DNA-binding specificity and identification of binding motifs with single base-pair resolution. Here we describe the application of EMSAs for the study of interactions of the brassinosteroid-regulated TFs, BRASSINAZOLE-RESISTANT1, (BZR1), BRI1-ETHYL METHANESULFONATE-SUPPRESSOR1 (BES1)/BZR2, and CESTA with putative binding sites. The classical approach using radiolabeled probes, as well as the more recent application of fluorescent probes, is described and the advantages and disadvantages of both methods are discussed.

  17. Gold nanoparticles deposited capillaries for in-capillary microextraction capillary zone electrophoresis of monohydroxy-polycyclic aromatic hydrocarbons.

    Science.gov (United States)

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

    2011-03-01

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

  18. Cold neutron microprobe for materials analysis using tapered capillary optics

    Science.gov (United States)

    Sharov, V. A.; Xiao, Q.-F.; Ponomarev, I. Yu.; Mildner, D. F. R.; Chen-Mayer, H. H.

    2000-09-01

    A prototype monolithic capillary lens for focusing neutrons produced by thermally drawing straight multicapillary bundles has been characterized with cold neutrons, and gives an intensity gain of a factor of 25 at a focal distance of 8 mm, over the focal spot area of width 87 μm. This is over an order of magnitude smaller in area than for the multifiber capillary lens. The spatial resolution available with the lens has been tested with prompt gamma measurements on slivers of dysprosium. Background problems that can affect the spatial resolution of measurements taken at the focal position of the lens are addressed. The boron glass of the tapered monolithic lens provides good shielding from unfocused neutrons in the vicinity of the lens focus.

  19. Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

    Directory of Open Access Journals (Sweden)

    Injac Rade

    2008-01-01

    Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

  20. Enhanced electrophoretic DNA separation in photonic crystal fiber.

    Science.gov (United States)

    Sun, Yi; Nguyen, Nam-Trung; Kwok, Yien Chian

    2009-07-01

    Joule heating generated by the electrical current in capillary electrophoresis leads to a temperature gradient along the separation channel and consequently affects the separation quality. We describe a method of reducing the Joule heating effect by incorporating photonic crystal fiber into a micro capillary electrophoresis chip. The photonic crystal fiber consists of a bundle of extremely narrow hollow channels, which ideally work as separation columns. Electrophoretic separation of DNA fragments was simultaneously but independently carried out in 54 narrow capillaries with a diameter of 3.7 microm each. The capillary bundle offers more efficient heat dissipation owing to the high surface-to-volume ratio. Under the same electrical field strength, notable improvement in resolution was obtained in the capillary bundle chip.

  1. Capillaries for use in a multiplexed capillary electrophoresis system

    Science.gov (United States)

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

    1997-12-09

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

  2. Microchip capillary electrophoresis for frontal analysis of free bilirubin and study of its interaction with human serum albumin.

    Science.gov (United States)

    Nie, Zhou; Fung, Ying Sing

    2008-05-01

    To meet the need for bedside monitoring of free bilirubin for neonates under critical conditions, a microfluidic chip was fabricated and tested for its coupling with CE/frontal analysis (FA) to determine free bilirubin and study of its binding interaction with HSA, which regulated its concentration in plasma. The poly(methyl methacrylate) (PMMA) multichannel chip was fabricated by CO2 laser ablation and bonded with a fused-silica separation capillary for CE/FA separation with UV detection. The chip was designed to allow a complete assay of four electrophoretic runs using preconditioned channels to speed up the determination of free bilirubin and to deliver quick results for bedside monitoring. Under optimized conditions, the linear working range for free bilirubin was from 10 to 200 micromol with RSDs from 2.1 to 5.0% for n=3, and the LOD at 9 micromol for S/N=3. From a binding study between bilirubin and HSA under FA condition, the second binding constant for bilirubin-HSA was determined as 1.07x10(5) L/mol and the number of binding sites per HSA as 3.46. The results enabled the calculation of free bilirubin for jaundiced infants based on the clinically significant level of total bilirubin, producing a range of 118.3-119.4 micromol/L. The developed method is shown to meet the clinical requirement with additional margin of protection to detect the early rising level of free bilirubin prior to jaundice condition. The low-cost microchip CE/FA device is shown to produce quick results with high potential to deliver a suitable bed-side monitoring method for bilirubin management in neonates.

  3. 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.

  4. 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.

  5. Novel covalently coated diazoresin/polyvinyl alcohol capillary column for the analysis of proteins by capillary electrophoresis.

    Science.gov (United States)

    Yu, Bing; Liu, Peng; Cong, Hailin; Tang, Jianguo; Zhang, Lixin

    2012-10-01

    A novel method for the preparation of covalently linked capillary coatings of PVA was demonstrated using photosensitive diazoresin (DR) as coupling agents. Layer-by-layer self-assembly film of DR and PVA based on hydrogen bonding was first fabricated on the inner wall of capillary, then the hydrogen bonding was converted into covalent bonding after treatment with UV light through the unique photochemistry reaction of DR. The covalently bonded coatings suppressed basic protein adsorption on the inner surface of capillary, and thus a baseline separation of lysozyme, cytochrome c and BSA was achieved using CE. Compared with bare capillary or noncovalently bonded DR/PVA coatings, the covalently linked DR/PVA capillary coatings not only improved the CE separation performance for proteins, but also exhibited good stability and repeatability. Due to the replacement of highly toxic and moisture-sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide a green and easy way to make the covalently coated capillaries for CE.

  6. 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.

  7. 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.

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Single-strand conformation polymorphism analysis using capillary array electrophoresis for large-scale mutation detection.

    Science.gov (United States)

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

    2007-01-01

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

  14. 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.

  15. Optimization of micellar electrokinetic capillary chromatography method using central composite design for the analysis of components in Yangwei granule

    Institute of Scientific and Technical Information of China (English)

    Shu-fang WANG; Hai-yan FANG; Hai-bin QU

    2011-01-01

    Central composite design (CCD), together with multiple linear regression, was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography (MEKC) for the determination of albiflorin, paeoniflorin, liquiritin, and glycyrrhizic acid in the traditional Chinese medicine (TCM) prescription,Yangwei granule. Concentrations of sodium deoxycholate (SDC) and borate, and proportions of ammonia, acetonitrile,and methanol were optimized. The total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation efficiency. The optimum electrophoretic buffer contained 80 mmol/L SDC, 20 mmol/L borate, 5% (v/v) methanol, 0.5% (v/v) ammonia, and 5% (v/v) acetonitrile. The correlation coefficients (R2) between the peak areas and the corresponding concentrations of analytes were greater than 0.9956. The limits of detection (LODs) (S/N=3) of the analytes were 0.97-4.00 μg/mi. The results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.

  16. 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.

  17. Capillary electrophoresis-time of flight-mass spectrometry using noncovalently bilayer-coated capillaries for the analysis of amino acids in human urine.

    Science.gov (United States)

    Ramautar, Rawi; Mayboroda, Oleg A; Derks, Rico J E; van Nieuwkoop, Cees; van Dissel, Jaap T; Somsen, Govert W; Deelder, André M; de Jong, Gerhardus J

    2008-06-01

    A capillary electrophoresis-time of flight-mass spectrometry (CE-TOF-MS) method for the analysis of amino acids in human urine was developed. Capillaries noncovalently coated with a bilayer of Polybrene (PB) and poly(vinyl sulfonate) (PVS) provided a considerable EOF at low pH, thus facilitating the fast separation of amino acids using a BGE of 1 M formic acid (pH 1.8). The PB-PVS coating proved to be very consistent yielding stable CE-MS patterns of amino acids in urine with favorable migration time repeatability (RSDs capillary preconcentration step based on pH-mediated stacking allowing 100-nL sample injection (i.e. ca. 4% of capillary volume). As a result, LODs for amino acids were down to 20 nM while achieving satisfactory separation efficiencies. Preliminary validation of the method with urine samples showed good linear responses for the amino acids (R(2) >0.99), and RSDs for peak areas were <10%. Special attention was paid to the influence of matrix effects on the quantification of amino acids. The magnitude of ion suppression by the matrix was similar for different urine samples. The CE-TOF-MS method was used for the analysis of urine samples of patients with urinary tract infection (UTI). Concentrations of a subset of amino acids were determined and compared with concentrations in urine of healthy controls. Furthermore, partial least squares-discriminant analysis (PLS-DA) of the CE-TOF-MS dataset in the 50-450 m/z region showed a distinctive grouping of the UTI samples and the control samples. Examination of score and loadings plot revealed a number of compounds, including phenylalanine, to be responsible for grouping of the samples. Thus, the CE-TOF-MS method shows good potential for the screening of body fluids based on the analysis of endogenous low-molecular weight metabolites such as amino acids and related compounds.

  18. Determination of the Acid-Base Dissociation Constant of Acid-Degradable Hexamethylenetetramine by Capillary Zone Electrophoresis.

    Science.gov (United States)

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

    2016-01-01

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

  19. A comparison of nano-electrospray gas-phase electrophoretic mobility macromolecular analysis and matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometry for the characterization of the recombinant coagulation glycoprotein von Willebrand factor.

    Science.gov (United States)

    Kemptner, Jasmin; Marchetti-Deschmann, Martina; Müller, Roland; Ivens, Andreas; Turecek, Peter; Schwarz, Hans Peter; Allmaier, Günter

    2010-03-01

    Von Willebrand factor (VWF), an adhesive glycoprotein with an approximate molecular weight (MW) of the monomer of 260 kDa, circulates in human blood plasma as a series of multimers ranging in size up to 20.000 kDa; thus the determination of the accurate MW of the monomer is of great importance and due to its high MW quite challenging. In this study accurate MW determination of intact recombinant VWF monomer (rVWF) was performed with GEMMA (gas-phase electrophoretic mobility macromolecular analysis) and MALDI TOF MS (matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometry). Three rVWF preparations with differing buffer systems and glycoprotein concentrations were analyzed. First investigations directed towards heterogeneity determination by means of capillary gel electrophoresis (CGE)-on-the-chip with a laser-induced fluorescence detector revealed two compounds (MW of 277 kDa (migration time 44.3 s) and 341 kDa (migration time 49.5 s)) present in each sample to varying extents, namely mature and pro-rVWF. MALDI MS analysis in the linear positive ion mode allowed the detection of mature rVWF with an exact MW of 256.1 kDa (+/-0.8%) and pro-rVWF with a MW of 349.8 kDa (+/-0.8%). Two samples containing pro-rVWF in very minor concentration resulted in GEMMA detection of the mature rVWF with a MW of 227.4 kDa (+/-2.5%), derived from the measured globular size of 10.9 nm. For one sample containing both rVWF species in almost equal concentrations no differentiation of the two species was possible with GEMMA. Due to its lower resolution only a peak representing a mixture of both species at 11.8 nm could be observed, yielding a MW of 298.8 kDa (+/-1.6%).

  20. 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

  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. 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.

  3. Electrophoretically mediated microanalysis for characterization of the enantioselective CYP3A4 catalyzed N-demethylation of ketamine.

    Science.gov (United States)

    Ying Kwan, Hiu; Thormann, Wolfgang

    2012-11-01

    Execution of an enzymatic reaction performed in a capillary with subsequent electrophoretic analysis of the formed products is referred to as electrophoretically mediated microanalysis (EMMA). An EMMA method was developed to investigate the stereoselectivity of the CYP3A4-mediated N-demethylation of ketamine. Ketamine was incubated in a 50 μm id bare fused-silica capillary together with human CYP3A4 Supersomes using a 100 mM phosphate buffer (pH 7.4) at 37°C. A plug containing racemic ketamine and the NADPH regenerating system including all required cofactors for the enzymatic reaction was injected, followed by a plug of the metabolizing enzyme CYP3A4 (500 nM). These two plugs were bracketed by plugs of incubation buffer to ensure proper conditions for the enzymatic reaction. The rest of the capillary was filled with a pH 2.5 running buffer comprising 50 mM Tris, phosphoric acid, and 2% w/v of highly sulfated γ-cyclodextrin. Mixing of reaction plugs was enhanced via application of -10 kV for 10 s. After an incubation of 8 min at 37°C without power application (zero-potential amplification), the capillary was cooled to 25°C within 3 min followed by application of -10 kV for the separation and detection of the formed enantiomers of norketamine. Norketamine formation rates were fitted to the Michaelis-Menten model and the elucidated values for V(max) and K(m) were found to be comparable to those obtained from the off-line assay of a previous study.

  4. 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.

  5. 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.

  6. 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.

  7. Analysis of electrophoretic soil humic acids fractions by reversed-phase high performance liquid chromatography with on-line absorbance and fluorescence detection.

    Science.gov (United States)

    Trubetskoj, Oleg A; Richard, Claire; Guyot, Ghislain; Voyard, Guillaume; Trubetskaya, Olga E

    2012-06-22

    A combination of reversed-phase high performance liquid chromatography (RP HPLC) with on-line absorbance and fluorescence detection was used for analysis of chernozem soil humic acids (HAs) and their fractions A, B and C+D with different electrophoretic mobility (EM) and molecular size (MS). Samples were injected onto the column at the identical volume and absorbance. All chromatograms exhibit the resolution of seven peaks. The estimation of relative recovery of HAs and fractions from the reverse-phase column has been done. High MS fraction A, which possesses the low EM, is essentially more hydrophobic (73% of the fraction amount remained adsorbed on the column) and aliphatic than medium MS and EM fraction B (33% of the fraction amount remained adsorbed on the column). The most hydrophilic and aromatic properties belong to low MS fraction C+D, which possess the highest EM and practically was not adsorbed on the column. The hydrophobicity of the bulk HAs lies within the range of fractions hydrophobicity. The absorption spectra of bulk HAs, electrophoretic fractions A, B, C+D and corresponding RP HPLC peaks were featureless but had differences in the values of absorbance ratio at 300 and 400 nm (A3/A4). For fractions A and B this ratio gradually decreased from peak 1 to 7 (from 3.05 to 2.80 and 3.00 to 2.40, respectively). This trend was less pronounced in HAs and practically absent in fraction C+D, where ratio A3/A4 varied within a small range. The strong relationship between fluorescence properties, EM, MS, polarity and aliphaticity/aromaticity of HAs fractions was found. Humic and protein-like fluorescence had different polarity nature. The protein-like fluorescence is located in humic material which irreversibly adsorbed on the reverse-phase column and not subjected to RP HPLC characterization. The humic-like fluorescence at Ex/Em 270/450 nm is mostly located in the hydrophilic peak of low MS fraction C+D. Taking into account that high MS fraction A consisted

  8. 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)

    Zhang, Yonghua [Iowa State Univ., Ames, IA (United States)

    2000-01-01

    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

  9. 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

  10. 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.

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

    Science.gov (United States)

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

    2006-09-01

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

  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. Determination of cyanide in microsamples by means of capillary flow injection analysis with amperometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Backofen, U. [Leipzig Univ. (Germany). Sektion 8 - Chemie; Matysik, F.-M. [Department of Chemistry, University of Coimbra (Portugal); Werner, G. [Leipzig Univ. (Germany). Sektion 8 - Chemie

    1996-10-01

    A new approach for determining cyanide in microsamples is described. The method is based on capillary flow injection analysis (CFIA) with amperometric detection. The sensing electrode is a silver-plated microdisk electrode, where cyanide can react under formation of a dicyanoargentate complex. A remarkably low mass detection limit of 231 fmol cyanide is obtained for an injection volume of 60 nl. The sample throughput of the CFIA-arrangement is comparable with a conventional sized FIA-system. A practical application is given by analyzing the cyanide (amygdalin) concentration in apple kernels. (orig.). With 5 figs.

  15. Analysis of bioactive ingredients in the brown alga Fucus vesiculosus by capillary electrophoresis and neutron activation analysis.

    Science.gov (United States)

    Truus, Kalle; Vaher, Merike; Koel, Mihkel; Mähar, Andres; Taure, Imants

    2004-07-01

    Two different types of bioactive components of the seaweed Fucus vesiculosus were analysed: (1) polyphenols (phlorotannins) by capillary electrophoresis (CE) and (2) mineral part (including bioactive microelements) by neutron activation analysis (NAA). CE experiments were carried out using a UV detector (at 210 nm) and an uncoated silica capillary. The best separation was achieved at a voltage of 20 kV using borate or acetate buffer in a methanol/acetonitrile mixture as background electrolyte. The CE analysis data were confirmed by high-performance liquid chromatography (HPLC). Determination of mineral composition of algal biomass by NAA was performed on the basis of various nuclides; the best results (from 38 elements determined) were obtained for Mn, Fe, Zn, As, Br, Sr, I, Ba, Au and Hg.

  16. 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.

  17. Capillary sample

    Science.gov (United States)

    ... several times a day using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a limited ... do not constitute endorsements of those other sites. Copyright 1997-2017, A.D.A.M., Inc. Duplication ...

  18. Characterization of phosphoproteins from electrophoretic gels by nanoscale Fe(III) affinity chromatography with off-line mass spectrometry analysis

    DEFF Research Database (Denmark)

    Stensballe, A; Andersen, Søren; Jensen, Ole Nørregaard

    2001-01-01

    Detailed characterization of phosphoproteins as well as other post-translationally modified proteins is required to fully understand protein function and regulatory events in cells and organisms. Here we present a mass spectrometry (MS) based experimental strategy for the identification and mapping...... chromatography (Fe(III)-IMAC) columns were employed for enrichment of phosphorylated peptides from crude peptide mixtures prior to off-line analysis by matrix-assisted laser desorption/ionization (MALDI) MS or nanoelectrospray tandem mass spectrometry (MS/MS). An optimized and sensitive procedure for alkaline...... of phosphorylation sites. The advantages and limitations of the experimental strategy was demonstrated by enrichment, identification and sequencing of phosphopeptides from the model proteins ovalbumin and bovine beta-casein isolated by gel electrophoresis. Furthermore, an autophosphorylation site at Ser-3...

  19. Tudy on drug displacement interactions by capillary electrophoresis-frontal analysis

    Institute of Scientific and Technical Information of China (English)

    Zhou Dawei; Li Famei

    2006-01-01

    The interaction between 18-methyl norethindrone and ketoprofen,including the displacement of ketoprofen from human serum albumin binding sites,was investigated by the capillary electrophoresis-frontal analysis method (CE-FA)at room temperature.A very large sample plug was introduced hydrostatically into the capillary(65 cm x 50 μm i.d.;effective length of 35 cm)over 80 s at a height difference of 11 cm.The working conditions for CE-FA separation are as follows:operating voltage,10 kV;running buffer,67 mmol.L-1 phosphate,pH 7.4.The unbound ketoprofen concentration was directly measured from the height of the frontal peak.When the concentration of 18-methyl norethindrone was increased from 0 to 200 μmol/L,the unbound ketoprofen concentration was found to increase from 22.4 to 26.4 μmol/L at 100 μmol/L total ketoprofen concentration and from 82.1 to 106.2 μmol/L at 200 μmol/L total ketoprofen concentration.From these data,it may be deduced that the administration of high concentration of 18-methyl norethindrone can displace ketoprofen from its secondary binding site.

  20. Multiresidue analysis of phenylurea herbicides in environmental waters by capillary electrophoresis using electrochemical detection.

    Science.gov (United States)

    Chicharro, M; Bermejo, E; Sánchez, A; Zapardiel, A; Fernandez-Gutierrez, A; Arraez, D

    2005-05-01

    A rapid multiresidue method has been developed for the analysis of seven phenylurea herbicides in the presence of two s-triazines in environmental waters. A simple end-column electrochemical detector was used in combination with a commercially-available capillary electrophoresis instrument with UV detection. The determination of phenylurea pesticides using micellar electrokinetic capillary chromatography with electrochemical detection represents the first such determination that has been reported. In both detection systems, linear ranges were obtained for the seven phenylurea herbicides at concentrations lower than 2.0x10(-5) mol l(-1), in 0.020 mol l(-1) phosphoric acid at pH 7.0 and containing 0.020 mol l(-1) of sodium dodecylsulfate, in order to obtain selectivity in the additional separation by a micellar distribution process. Under these conditions a detection limit lower than 5.0x10(-6) mol l(-1) (0.25 pmol of pesticide) was achieved for most of them. The pesticides were resolved in less than 30 min.

  1. Heteroduplex analysis by capillary array electrophoresis for rapid mutation detection in large multiexon genes.

    Science.gov (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Pérez-Cabornero, Lucía; Sanz, David J; Esteban-Cardeñosa, Eva; Miner, Cristina

    2007-01-01

    Heteroduplex analysis (HA) has proven to be a robust tool for mutation detection. HA by capillary array electrophoresis (HA-CAE) was developed to increase throughput and allow the scanning of large multiexon genes in multicapillary DNA sequencers. HA-CAE is a straightforward and high-throughput technique to detect both known and novel DNA variants with a high level of sensitivity and specificity. It consists of only three steps: multiplex-PCR using fluorescently labeled primers, heteroduplex formation and electrophoresis in a multicapillary DNA sequencer. It allows, e.g., the complete coding and flanking intronic sequences of BRCA1 and BRCA2 genes from two patients (approximately 25 kb each) to be scanned in a single run of a 16-capillary sequencer, and has enabled us to detect 150 different mutations to date (both single nucleotide substitutions, or SNSs, and small insertions/deletions). Here, we describe the protocol developed in our laboratory to scan BRCA1, BRCA2, MLH1, MSH2 and MSH6 genes using an ABI3130XL sequencer. This protocol could be adapted to other instruments or to the study of other large multiexon genes and can be completed in 7-8 h.

  2. 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.

  3. Capillary electrophoresis micro X-ray fluorescence: a tool for benchtop elemental analysis.

    Science.gov (United States)

    Miller, Thomasin C; Joseph, Martha R; Havrilla, George J; Lewis, Cris; Majidi, Vahid

    2003-05-01

    A new tool was developed for separation and elemental detection by interfacing a simple capillary electrophoresis (CE) apparatus, constructed using a thin-walled fused-silica capillary, with a benchtop energy-dispersive micro X-ray fluorescence (MXRF) system. X-ray excitation and detection of the separated analytes was done using an EDAX Eagle II micro X-ray fluorescence system equipped with a polycapillary Rh target excitation source and a SiLi detector. It was demonstrated that this prototype system could be used for the separation and detection of species containing two different metals from one another, specifically Cu and Co. Free Co could also be separated from Co bound to cyanocobalamin (vitamin B-12). Two organic compounds were also separated from one another, a large biological protein, ferritin, from a small biological organic, cyanocobalamin. Preliminary average detection limits obtained on this system were on the order of 10(-)(4) M and compared favorably to those reported for the similar technique of CE-synchrotron XRF. CEMXRF allows for nondestructive, simultaneous, on-line, benchtop elemental analysis for chemical speciation applications.

  4. Capillary electrophoresis in a fused-silica capillary with surface roughness gradient.

    Science.gov (United States)

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

    2016-10-01

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

  5. Applications of capillary electrophoresis with chemiluminescence detection in clinical, environmental and food analysis. A review

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Francisco J.; Airado-Rodríguez, Diego; Moreno-González, David; Huertas-Pérez, José F.; García-Campaña, Ana M., E-mail: amgarcia@ugr.es

    2016-03-24

    This paper reviews the latest developments and analytical applications of chemiluminescence detection coupled to capillary electrophoresis (CE-CL). Different sections considering the most common CL systems have been included, such as the tris(2,2′-bipyridine)ruthenium(II) system, the luminol and acridinium derivative reactions, the peroxyoxalate CL or direct oxidations. Improvements in instrumental designs, new strategies for improving both resolution and sensitivity, and applications in different fields such as clinical, pharmaceutical, environmental and food analysis have been included. This review covers the literature from 2010 to 2015. - Highlights: • An up-to-date critical review about the evolution of CE-CL is presented. • Tris(2,2′-bipyridine)ruthenium(II) and luminol as the most used CL systems. • Instrumental designs and strategies for improving resolution and sensitivity. • Applications in clinical, pharmaceutical, environmental and food analysis.

  6. 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.

  7. 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.

  8. 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

  9. Rapid mutation detection in complex genes by heteroduplex analysis with capillary array electrophoresis.

    Science.gov (United States)

    Velasco, Eladio; Infante, Mar; Durán, Mercedes; Esteban-Cardeñosa, Eva; Lastra, Enrique; García-Girón, Carlos; Miner, Cristina

    2005-06-01

    Mutational analysis of large multiexon genes without prevalent mutations is a laborious undertaking that requires the use of a high-throughput scanning technique. The Human Genome Project has enabled the development of powerful techniques for mutation detection in large multiexon genes. We have transferred heteroduplex analysis (HA) by conformation-sensitive gel electrophoresis of the two major breast cancer (BC) predisposing genes, BRCA1 and BRCA2, to a multicapillary DNA sequencer in order to increase the throughput of this technique. This new method that we have called heteroduplex analysis by capillary array electrophoresis (HA-CAE) is based on the use of multiplex-polymerase chain reaction (PCR), different fluorescent labels and HA in a 16-capillary DNA sequencer. To date, a total of 114 different DNA sequence variants (19 insertions/deletions and 95 single-nucleotide substitutions - SNS) of BRCA1 and BRCA2 from 431 unrelated BC families have been successfully detected by HA-CAE. In addition, we have optimized the multiplex-PCR conditions for the colorectal cancer genes MLH1 and MSH2 in order to analyze them by HA-CAE. Both genes have been amplified in 13 multiplex groups, which contain the 35 exons, and their corresponding flanking intronic sequences. MLH1 and MSH2 have been analyzed in nine hereditary nonpolyposis colorectal cancer patients, and we have found six different DNA changes: one complex deletion/insertion mutation in MLH1 exon 19 and another five SNS. Only the complex mutation and one SNS may be classified as cancer-prone mutations. Our experience has revealed that HA-CAE is a simple, fast, reproducible and sensitive method to scan the sequences of complex genes.

  10. 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.

  11. 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.

  12. 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%.

  13. 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.

  14. 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.

  15. 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.

  16. New approaches for capillary electrophoresis–mass spectrometry in drug analysis : Evaluation of photo-, chemical and thermospray ionization

    NARCIS (Netherlands)

    Hommerson, P.

    2009-01-01

    During the past two decades, capillary electrophoresis–mass spectrometry (CE–MS) has emerged as a powerful analytical tool that is well suited to the analysis of pharmaceutical samples. CE–MS combines efficient and fast separation with mass-selective detection and can be considered as orthogonal to

  17. Capillary electrophoresis analysis of inorganic cations in post-blast residue extracts applying a guanidinium-based electrolyte and bilayer-coated capillaries.

    Science.gov (United States)

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

    2011-06-01

    A new CE method was developed for the identification and quantitation of inorganic cations in post-blast residues. The simultaneous analysis in 20 min total runtime of eight cations in post-blast residues (ammonium, potassium, monomethylammonium, calcium, sodium, magnesium, strontium), plus lithium cation as the internal reference, was carried out with a BGE involving a non-CMR (carcinogenic, mutagenic, and harmful to reproduction) chromophore (guanidinium cation) and a double-layer modified capillary (hexadimethrine bromide/polyvinylsulfonate). A study of UV detection conditions using guanidinium ion as the probe led us to set the analysis and reference wavelengths and their associated bandwidths as well as the probe concentration fixed at 15 mM. The successive multiple ionic-polymer layer approach limited the cation adsorption on capillary wall and improved the EOF stability. These caused a significant improvement in method repeatability. Intermediate precisions were 2.4% for corrected areas and 1.3% for normalized migration times. Limits of detection close to 1 mg/L for all cations were obtained. The matrix effects were studied with chemometric approach for different matrices representative of those collected after explosion. Tests with blank matrix extracts of soil, cloth, and with simulated matrix extract containing 800 mg/L Ca²⁺ and 500 mg/L Fe²⁺ were carried out and no significant matrix effects were observed. Finally, analyses of real residues collected after cash dispenser and homemade firework explosions demonstrate excellent correlation between the CE results and those obtained with the ion chromatography method used routinely.

  18. 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.

  19. 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…

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

    Science.gov (United States)

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

  1. Shear distortion and failure of capillary bridges. Wetting information beyond contact angle analysis.

    Science.gov (United States)

    Wang, Liming; McCarthy, Thomas J

    2013-06-25

    Water capillary bridges are prepared that span hydrophilic pinning features on parallel opposing smooth, flat, and hydrophobic surfaces. These bridges are distorted by shearing the parallel plates at a low rate. The capillary bridges lengthen and distort to balance Laplace pressure (equilibrate mean curvature) as the features are separated and eventually rupture at a distance that is a function of the liquid volume, the advancing and receding contact angles of the surfaces, the separation between the parallel surfaces, and in particular, the shape and orientation of the hydrophilic pinning features. Two modes of capillary bridge failure are observed: (1) tensile, in which the capillary bridge breaks to form sessile drops on both the upper and lower surfaces, and (2) sessile, in which sessile capillary bridge rupture occurs on one surface to form a puddle (contact-line-distorted sessile drop) on the feature and a retained capillary bridge spanning the hydrophobic surface and the hydrophilic feature on the opposing surface. The shape and orientation of the features control the mode of capillary bridge failure as well as the distribution of water between the two separate sessile drops or the retained capillary bridge and the puddle.

  2. 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.

  3. Analytical study of Joule heating effects on electrokinetic transportation in capillary electrophoresis.

    Science.gov (United States)

    Xuan, Xiangchun; Li, Dongqing

    2005-02-04

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

  4. Optimization of capillary array electrophoresis single-strand conformation polymorphism analysis for routine molecular diagnostics.

    Science.gov (United States)

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

    2006-10-01

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

  5. 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.

  6. Applications of graphene electrophoretic deposition. A review.

    Science.gov (United States)

    Chavez-Valdez, A; Shaffer, M S P; Boccaccini, A R

    2013-02-14

    This Review summarizes research progress employing electrophoretic deposition (EPD) to fabricate graphene and graphene-based nanostructures for a wide range of applications, including energy storage materials, field emission devices, supports for fuel cells, dye-sensitized solar cells, supercapacitors and sensors, among others. These carbonaceous nanomaterials can be dispersed in organic solvents, or more commonly in water, using a variety of techniques compatible with EPD. Most deposits are produced under constant voltage conditions with deposition time also playing an important role in determining the morphology of the resulting graphene structures. In addition to simple planar substrates, it has been shown that uniform graphene-based layers can be deposited on three-dimensional, porous, and even flexible substrates. In general, electrophoretically deposited graphene layers show excellent properties, e.g., high electrical conductivity, large surface area, good thermal stability, high optical transparency, and robust mechanical strength. EPD also enables the fabrication of functional composite materials, e.g., graphene combined with metallic nanoparticles, with other carbonaceous materials (e.g., carbon nanotubes) or polymers, leading to novel nanomaterials with enhanced optical and electrical properties. In summary, the analysis of the available literature reveals that EPD is a simple and convenient processing method for graphene and graphene-based materials, which is easy to apply and versatile. EPD has, therefore, a promising future for applications in the field of advanced nanomaterials, which depend on the reliable manipulation of graphene and graphene-containing systems.

  7. 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.

  8. Self-assembled and covalently linked capillary coating of diazoresin and cyclodextrin-derived dendrimer for analysis of proteins by capillary electrophoresis.

    Science.gov (United States)

    Yu, Bing; Chi, Ming; Han, Yuxing; Cong, Hailin; Tang, Jianbin; Peng, Qiaohong

    2016-05-15

    Self-assembled and covalently linked capillary coatings of cyclodextrin-derived (CD) dendrimer were prepared using photosensitive diazoresin (DR) as a coupling agent. Layer by layer (LBL) self-assembled DR/CD-dendrimer coatings based on ionic bonding was fabricated first on the inner surface of capillary, and subsequently converted into covalent bonding after treatment with UV light through a unique photochemistry reaction of DR. Protein adsorption on the inner surface of capillary was suppressed by the DR/CD-dendrimer coating, and thus a baseline separation of lysozyme (Lys), myoglobin (Mb), bovine serum albumin (BSA) and ribonuclease A (RNase A) was achieved using capillary electrophoresis (CE). Compared with the bare capillary, the DR/CD-dendrimer covalently linked capillary coatings showed excellent protein separation performance with good stability and repeatability. Because of the replacement of highly toxic and moisture sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide an environmentally friendly and simple way to prepare the covalently coated capillaries for CE.

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

    Science.gov (United States)

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

    2016-03-11

    Self-assembled and covalently linked capillary coatings of carboxyl fullerenes (C60-COOH) were prepared using photosensitive diazoresin (DR) as a coupling agent. Layer by layer (LBL) self-assembled DR/C60-COOH coatings based on ionic bonding was fabricated first on the inner surface of silica capillary, and subsequently converted into covalent bonding after treatment with UV light through a unique photochemistry reaction of DR. The covalently bonded coatings had the ability of suppressing protein adsorption on the inner surface of silica capillary, and thus the baseline separation of lysozyme (Lys), cytochrome c (Cyt-c), bovine serum albumin (BSA) and myoglobin (Mb) was achieved within 13min by using capillary electrophoresis (CE). The covalently linked DR/C60-COOH capillary coatings presented good chemical stability and repeatability. The reproducibility of the separation of proteins was less than 1%, 2.5%, and 3.5%, respectively, for run-to-run, day-to-day, capillary-to-capillary, respectively; and the RSD of migration time for the proteins are all less than 2.5% after a continuous 100 times running in a coating column. Compared with DR/graphene oxide (GO) coatings prepared by the same method, the DR/C60-COOH capillary coatings showed excellent protein separation performance due to a self-lubrication based anti-fouling mechanism. Because of the replacement of highly toxic and moisture sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide an environmentally friendly and simple way to prepare the covalently coated capillaries for CE.

  10. 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)

  11. Fast analysis of glibenclamide and its impurities: quality by design framework in capillary electrophoresis method development.

    Science.gov (United States)

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

    2015-10-01

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

  12. Capillary ion-exchange chromatography with nanogram sensitivity for the analysis of monoclonal antibodies.

    Science.gov (United States)

    Rea, Jennifer C; Freistadt, Benny S; McDonald, Daniel; Farnan, Dell; Wang, Yajun Jennifer

    2015-12-11

    Ion-exchange chromatography (IEC) is widely used for profiling the charge heterogeneity of proteins, including monoclonal antibodies (mAbs). Despite good resolving power and robustness, ionic strength-based ion-exchange separations are generally product specific and can be time consuming to develop. In addition, conventional analytical scale ion-exchange separations require tens of micrograms of mAbs for each injection, amounts that are often unavailable in sample-limited applications. We report the development of a capillary IEC (c-IEC) methodology for the analysis of nanogram amounts of mAb charge variants. Several key modifications were made to a commercially available liquid chromatography system to perform c-IEC for charge variant analysis of mAbs with nanogram sensitivity. We demonstrate the method for multiple monoclonal antibodies, including antibody fragments, on different columns from different manufacturers. Relative standard deviations of <10% were achieved for relative peak areas of main peak, acidic and basic regions, which are common regions of interest for quantifying monoclonal antibody charge variants using IEC. The results herein demonstrate the excellent sensitivity of this c-IEC characterization method, which can be used for analyzing charge variants in sample-limited applications, such as early-stage candidate screening and in vivo studies.

  13. 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...

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  16. 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.

  17. [Pyogenic granuloma vs. lobular capillary hemangioma. Histopathological analysis and epidemiology (Venezuela)].

    Science.gov (United States)

    Tinoco, P J; Sanalzar, N

    1989-01-01

    A review of the literature is done concerning Pyogenic Granuloma. From two hundred and thirty eight cases of our files. Twenty four cases are separated which are considered histopathologically different and to which the term Lobular Capillary Hemangioma is more applicable. Epidemiologic studies are analyzed and conclusions are established. Pyogenic Granuloma is more a reactive type of lesion of inflammatory nature, while Lobular Capillary Hemangioma separated as an entity is considered a lesion of benign neoplastic nature and vascular origin.

  18. Capillary gas chromatographic analysis of alditol acetates of neutral and amino sugars in bacterial cell walls.

    Science.gov (United States)

    Fox, A; Morgan, S L; Hudson, J R; Zhu, Z T; Lau, P Y

    1983-02-18

    Several improvements in the preparation of alditol acetates of neutral and amino sugars and in the preparation of glass capillary columns for their separation are described. Modifications in sample preparation permitted the simultaneous processing of multiple samples and eliminated extraneous background peaks. Efficient and inert columns were tailor-made for the separation of alditol acetates of neutral and amino sugars by leaching glass capillaries with aqueous hydrochloric acid and dynamically coating with SP-2330.

  19. 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...

  20. Evaluation of migration behaviour of therapeutic peptide hormones in capillary electrophoresis using polybrene-coated capillaries.

    Science.gov (United States)

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

    2010-02-01

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

  1. 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 <10 min without sample derivatization. The separation electrolyte was 20 mm TAPS/Lithium, pH 8.7. Average minimal detectable amounts for MDMA and mCPP were 0.04 mg/tablet, several orders of magnitude lower than the minimum amount encountered in a tablet. Seven different Ecstasy tablets seized in Rio de Janeiro, Brazil, were analyzed by CE-C(4) D and compared against routine gas chromatography-mass spectrometry (GC-MS). The CE method demonstrated sufficient selectivity to discriminate the two target drugs, MDMA and mCPP, from the other drugs present in seizures, namely amphepramone, fenproporex, caffeine, lidocaine, and cocaine. Separation was performed in <90 sec. The advantages of using C(4) D instead of traditional CE-UV methods for in-field analysis are also discussed.

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

    Directory of Open Access Journals (Sweden)

    Melania Cârcu-Dobrin

    2017-03-01

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

  3. 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.

  4. 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

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

    Science.gov (United States)

    Soares, Belinda; Passos, Helena; Freire, Carmen S R; Coutinho, João A P; Silvestre, Armando J D; Freire, Mara G

    2016-09-07

    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.

  6. Metabolism of excised embryos of Lupinus luteus L. VI. An electrophoretic analysis of some dehydrogenases in cultured embryos as compared with the normal seedling axes

    Directory of Open Access Journals (Sweden)

    J. Czosnowski

    2015-05-01

    Full Text Available The electrophoretic patterns (disc electrophoresis of the studied dehydrogenases: glucose-6-phosphate - (A, malate - (B, glutamate - (C, alcohol - (D and lactate dehydrogenase (E, in the axial organs of isolated Lupinus luteus embryos and seedlings cultivated over 12 days are characterized by great similarities. With time, after the third day of cultivation the patterns begin to become less deyeloped. Analyses performed during the first 10 hours of imbibition of seed parts indicate that the maximal development of isozyme patterns occurs during the third hour after which the patterns become poorer. The most uniform type of pattern. and the lowest number of isozymes was shown by glutamate dehydrogenase, the richest pattern was shown by malate dehydrogenase. No band common for a 11 the 27 experimental elements was found.

  7. Analysis of effect of electrolyte types on electrokinetic energy conversion in nanoscale capillaries.

    Science.gov (United States)

    Chein, Reiyu; Tsai, Kunyong; Yeh, Liying

    2010-01-01

    An analytical study on the effect of electrolyte types on the electrokinetic energy conversion is presented using nanoscale cylindrical capillary, which is either positively or negatively charged. The sign of surface charge determines the role and concentration magnitude of ions in the capillary and the energy conversion performance. Our study shows that the electrokinetic energy conversion performance (maximum efficiency, pressure rise and streaming potential) are approximately identical for 1:1 (KCl), 2:1 (CaCl2) and 3:1 (LaCl3) electrolytes when capillary is positively charged. For negatively charged capillary, energy conversion performance degrades significantly with the increase of counter-ion valence. For both positively and negatively charged capillaries, higher maximum efficiency can be resulted in low bulk concentration and surface charge density regimes. However, high maximum pressure rise generation for the pumping is found in the low bulk concentration and high surface charge density regimes. For the electric power generation, higher maximum streaming potential is found when both bulk concentration and surface charge density are low.

  8. Optimization of a nano-enzymatic reactor for on-line tryptic digestion of polypeptide conjugates by capillary electrophoresis.

    Science.gov (United States)

    Ladner, Yoann; Coussot, Gaelle; Ebner, Stefanie; Ibrahim, Amal; Vidal, Laetitia; Perrin, Catherine

    2016-01-01

    This work aims at studying the optimization of an on-line capillary electrophoresis (CE)-based tryptic digestion methodology for the analysis of therapeutic polypeptides (PP). With this methodology, a mixture of surrogate peptide fragments and amino acid were produced on-line by trypsin cleavage (enzymatic digestion) and subsequently analyzed using the same capillary. The resulting automation of all steps such as injection, mixing, incubation, separation and detection minimizes the possible errors and saves experimental time. In this paper, we first study the differents parameters influencing PP cleavage inside the capillary (plug length, reactant concentration, incubation time, diffusion and electrophoretic plugs mixing). In a second part, the optimization of the electrophoretic separation conditions of generated hydrolysis products (nature, pH and ionic strength (I) of the background electrolyte (BGE)) is described. Using the optimized conditions, excellent repeatability was obtained in terms of separation (migration times) and proteolysis (number of products from enzymatic hydrolysis and corresponding amounts) demonstrating the robustness of the proposed methodology.

  9. 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.

  10. 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.

  11. 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.

  12. Capillary Index Score and Correlation with Outcomes in Acute Ischemic Stroke: A Meta-analysis

    Science.gov (United States)

    Jagani, Manoj; Brinjikji, Waleed; Murad, Mohammad H.; Rabinstein, Alejandro A.; Cloft, Harry J.; Kallmes, David F.

    2017-01-01

    Background and Purpose The capillary index score (CIS) has been recently introduced as a metric for rating the collateral circulation of ischemic stroke patients. Multiple studies in the last five years have evaluated the correlation of good CIS with clinical outcomes and suggested the use of CIS in selecting patients for endovascular treatment. We performed a meta-analysis of these studies comparing CIS with clinical outcomes. Methods We conducted a computerized search of three databases from January 2011 to November 2015 for studies related to CIS and outcomes. A CIS = 0 or 1 is considered poor (pCIS) and a CIS = 2 or 3 is considered favorable (fCIS). Using random-effect meta-analysis, we evaluated the relationship of CIS to neurological outcome (modified Rankin scale score ≤ 2), recanalization, and post-treatment hemorrhage. Meta-regression analysis of good neurological outcome was performed for adjusting baseline National Institutes of Health Stroke Scale (NIHSS) between groups. Results Six studies totaling 338 patients (212 with fCISs and 126 with pCISs) were included in the analysis. Patients with fCIS had higher likelihood of good neurological outcome [relative risk (RR) = 3.03; confidence interval (CI) = 95%, 2.05–4.47; p < 0.001] and lower risk of post-treatment hemorrhage (RR = 0.38; CI = 95%, 0.19–0.93; p = 0.04) as compared with patients in the pCIS group. When adjusting for baseline NIHSS, patients with fCIS had higher RR of good neurological outcome when compared with those with pCIS (RR = 2.94; CI = 95%, 1.23–7, p < 0.0001). Favorable CIS was not associated with higher rates of recanalization. Conclusions Observational evidence suggests that acute ischemic stroke patients with fCIS may have higher rates of good neurological outcomes compared with patients with pCIS, independent of baseline NIHSS. CIS may be used as another tool to select patients for endovascular treatment of acute ischemic stroke.

  13. Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites.

    Science.gov (United States)

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

    2014-10-01

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

  14. Capillary origami

    OpenAIRE

    Py, Charlotte; Reverdy, Paul; Doppler, L.; J. Bico; Roman, B.; Baroud, Charles,

    2007-01-01

    International audience; The hairs of a wet dog rushing out from a pond assemble into bundles; this is a common example of the effect of capillary forces on flexible structures. From a practical point of the deformation and adhesion of compliant structures induced by interfacial forces may lead to disastrous effects in mechanical microsystems.

  15. Recent advances on the use of cyclodextrins in the chiral analysis of drugs by capillary electrophoresis.

    Science.gov (United States)

    Saz, J M; Marina, M L

    2016-10-07

    The most recent advances on the use of cyclodextrins as chiral selectors in capillary electrophoresis for the enantioseparation of drugs are reviewed in this article. The types of cyclodextrins employed and the resolutions achieved are discussed. The use of dual chiral systems, modified capillaries, non-aqueous media or microfluidic devices is also included and the mechanisms for enantioseparation of drugs and the inversion of the enantiomer migration order are studied. The most relevant applications developed to carry out the quantitation of chiral drugs, to assess the enantiomeric purity of pharmaceutical formulations, to study their metabolism or to achieve criminalistic or forensic investigations are described. Articles published in the last six years (period from 2010 to 2015) are considered.

  16. Analysis of insecticidal proteins from Bacillus thuringiensis and recombinant Escherichia coli by capillary electrokinetic chromatography.

    Science.gov (United States)

    Luong, John H T; Male, Keith B; Mazza, Alberto; Masson, Luke; Brousseau, Roland

    2004-10-01

    Bacillus thuringiensis and recombinant Escherichia coli proteinaceous protoxins were subject to proteolysis and analyzed by capillary electrokinetic chromatography. Three resulting toxins (65 kDa) were baseline-resolved within 22 min using a 10 mM borate, pH 11 separation buffer consisting of 25 mM sodium dodecyl sulfate (SDS) and 30 mM phytic acid. The toxins displayed differential interactions with the SDS and phytic acid phases to effect their separation. The ion-pairing interaction between the analyte and phytic acid was also useful in preventing adsorption to the capillary walls and thus enhanced separation resolution and efficiency. The use of electrokinetic chromatography allows achievement of the separation in a significantly shorter time than conventional high-performance liquid chromatography (HPLC) using a diethylaminoethyl (DEAE) weak-anion exchanger.

  17. 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

      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.%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.

  18. 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.

  19. 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).

  20. 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.

  1. 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).

  2. Polyacrylamide medium for the electrophoretic separation of biomolecules

    Science.gov (United States)

    Madabhushi, Ramakrishna S.; Gammon, Stuart A.

    2003-11-11

    A polyacryalmide medium for the electrophoretic separation of biomolecules. The polyacryalmide medium comprises high molecular weight polyacrylamides (PAAm) having a viscosity average molecular weight (M.sub.v) of about 675-725 kDa were synthesized by conventional red-ox polymerization technique. Using this separation medium, capillary electrophoresis of BigDye DNA sequencing standard was performed. A single base resolution of .about.725 bases was achieved in .about.60 minute in a non-covalently coated capillary of 50 .mu.m i.d., 40 cm effective length, and a filed of 160 V/cm at 40.degree. C. The resolution achieved with this formulation to separate DNA under identical conditions is much superior (725 bases vs. 625 bases) and faster (60 min. vs. 75 min.) to the commercially available PAAm, such as supplied by Amersham. The formulation method employed here to synthesize PAAm is straight-forward, simple and does not require cumbersome methods such as emulsion polymerizaiton in order to achieve very high molecular weights. Also, the formulation here does not require separation of PAAm from the reaction mixture prior to reconstituting the polymer to a final concentration. Furthermore, the formulation here is prepared from a single average mol. wt. PAAm as opposed to the mixture of two different average mo. wt. PAAm previously required to achieve high resolution.

  3. Effect of temperature gradients on single-strand conformation polymorphism analysis in a capillary electrophoresis system using Pluronic polymer matrix.

    Science.gov (United States)

    Hwang, Hee Sung; Shin, Gi Won; Park, Han Jin; Ryu, Chang Y; Jung, Gyoo Yeol

    2013-09-02

    Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) analysis is a prominent bioseparation method based on the mobility diversity caused by sequence-induced conformational differences of single-stranded DNA. The use of Pluronic polymer matrix has opened up new opportunities for CE-SSCP, because it improved the resolution for various genetic analyses. However, there still exists a challenge in optimizing Pluronic-based CE-SSCP, because the physical properties of Pluronic solutions are sensitive to temperature, particularly near the gelation temperature, where the viscoelasticity of Pluronic F108 solutions sharply changes from that of a Newtonian fluid to a hydrogel upon heating. We have focused on a set of experiments to control the ambient temperature of the CE system with the aim of enhancing the reliability of the CE-SSCP analysis by using the Applied Biosystems ABI 3130xl genetic analyzer with Pluronic F108 solution matrix. The ambient temperature control allowed us to vary the inlet and outlet portion of the capillary column, while the temperature of the column was kept at 35°C. The resolution to separate 2 single-base-pair-differing DNA fragments was significantly enhanced by changing the temperature from 19 to 30°C. The viscoelastic properties of the F108 solution matrix upon heating were also investigated by ex situ rheological experiments with an effort to reveal how the development of gels in Pluronic solutions affects the resolution of CE-SSCP. We found that the column inlet and outlet temperatures of the capillary column have to be controlled to optimize the resolution in CE-SSCP by using the Pluronic matrix.

  4. Effect of passage number on electrophoretic mobility distributions of cultured human embryonic kidney cells

    Science.gov (United States)

    Kunze, M. E.

    1985-01-01

    A systematic investigation was undertaken to characterize population shifts that occur in cultured human embryonic kidney cells as a function of passage number in vitro after original explantation. This approach to cell population shift analysis follows the suggestion of Mehreshi, Klein and Revesz that perturbed cell populations can be characterized by electrophoretic mobility distributions if they contain subpopulations with different electrophoretic mobilities. It was shown that this is the case with early passage cultured human embryo cells.

  5. 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.

  6. Single-strand conformation polymorphism analysis of candidate genes for reliable identification of alleles by capillary array electrophoresis.

    Science.gov (United States)

    Kuhn, David N; Borrone, James; Meerow, Alan W; Motamayor, Juan C; Brown, J Steven; Schnell, Raymond J

    2005-01-01

    We investigated the reliability of capillary array electrophoresis-single strand conformation polymorphism (CAE-SSCP) to determine if it can be used to identify novel alleles of candidate genes in a germplasm collection. Both strands of three different size fragments (160, 245 and 437 bp) that differed by one or more nucleotides in sequence were analyzed at four different temperatures (18 degrees C, 25 degrees C, 30 degrees C, and 35 degrees C). Mixtures of amplified fragments of either the intron interrupting the C-terminal WRKY domain of the Tc10 locus or the NBS domain of the TcRGH1 locus of Theobroma cacao were electroinjected into all 16 capillaries of an ABI 3100 Genetic Analyzer and analyzed three times at each temperature. Multiplexing of samples of different size range is possible, as intermediate and large fragments were analyzed simultaneously in these experiments. A statistical analysis of the means of the fragment mobilities demonstrated that single-stranded conformers of the fragments could be reliably identified by their mobility at all temperatures and size classes. The order of elution of fragments was not consistent over strands or temperatures for the intermediate and large fragments. If samples are only run once at a single temperature, small fragments could be identified from a single strand at a single temperature. A combination of data from both strands of a single run was needed to identify correctly all four of the intermediate fragments and no combination of data from strands or temperatures would allow the correct identification of two large fragments that differed by only a single single-nucleotide polymorphism (SNP) from a single run. Thus, to adequately assess alleles at a candidate gene locus using SSCP on a capillary array, fragments should be strands and both temperatures, and undenatured double-stranded (ds)DNA molecular weight standards, such as ROX 2500, should be included as internal standards.

  7. Electrokinetic energy conversion efficiency analysis using nanoscale finite-length surface-charged capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Reiyu; Liao, Chencheng; Chen, Hongjie [Department of Mechanical Engineering, National Chung Hsing University, Taichung 402 (China)

    2009-02-15

    Electrokinetic power generation efficiency using a two-dimensional axisymmetrical model is numerically investigated. A finite-length nanoscale surface-charged cylindrical capillary with reservoirs connected at the capillary ends is considered as the physical domain. The Navier-Stokes, Laplace, Poisson, and Nernst-Planck equations are solved simultaneously to obtain the fluid flow, electrical potential, ion concentration and electrical current in the flow field. The energy conversion efficiency predicted using a one-dimensional model assuming an infinitely long channel, Boltzmann ion distribution and equal ionic electrical mobility is also carried out and compared with the two-dimensional result. The two-dimensional model results show that the electrostatic potential gradient resulting from the concentration changes at the capillary entrance and exit and fluid flow produce a conductive current that reduces the total current in the flow field. The conductive current due to the electrostatic potential gradient increases with the decrease in electrolyte bulk concentration and increase in surface charge density. This results in nonlinear variations in the electric current-voltage curve and maximum conversion efficiency as functions of the surface charge density and dimensionless Debye length when the electrolyte bulk concentration is low. Comparison of the maximum efficiencies predicted from one- and two-dimensional models indicates that the one-dimensional model is valid only when the dimensionless Debye length is large and the surface charge density is small because the electrostatic potential gradient is neglected. The two-dimensional model also predicts that optimum maximum energy conversion efficiency can be obtained when the dimensionless Debye length is equal to 2 and its magnitude increases with the increase in surface charge density. (author)

  8. Analysis of neutral surfactants by non-aqueous capillary electrophoresis using an electroosmotic flow reversal.

    Science.gov (United States)

    Desbène, A M; Geulin, L; Morin, C J; Desbène, P L

    2005-03-11

    The separation of KM 20, that is in fact a mixture of non-ionic surfactants, was carried out by non-aqueous capillary electrophoresis. This complex mixture resulting from the condensation of ethylene oxide with fatty alcohols does not have chromophoric moieties. So, we analysed it after derivatization by means of 3,5-dinitrobenzoyl chloride. The proposed approach is based both on the formation of complexes with alkaline or ammonium cations in methanol and on the utilisation of a positively charged capillary. From a comparative study on the capillary treatment procedure, we used hexadimethrine bromide as electroosmotic flow reverser in order to obtain both repeatable analyses and good resolutions of the largest KM 20 oligomers. Then, among the five cations used to form complexes with KM 20, we pointed out that ammonium cation led to the best resolutions. Moreover, we evidenced that the counter-ion of this cation had a great influence on resolution because it modified the magnitude of electroosmotic flow. Ion pair formation that is more or less strong between ammonium and its counter-ion was involved in this variation of electroosmotic flow. So, we calculated the association constants for various ammonium salts in methanol. Then, using ammonium chloride as background electrolyte, we optimised the concentration of this salt, in methanol, in order to reach the optimal separation of KM 20 oligomers. Thus, a baseline separation was obtained by using 6 x 10(-2) mol/L NH4Cl as running electrolyte. In these conditions, we separated, in about 30 min, more than 30 oligomers of KM 20. The distribution of these oligomers that was determined from the optimal separation, appeared consistent with that obtained from HPLC analyses. Indeed, we determined that the mean ethoxylation number was equal to 18 while its real value is equal to 20.

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

    Science.gov (United States)

    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.

  10. 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.

  11. 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...

  12. Surface initiated polymerization of a cationic monomer on inner surfaces of silica capillaries: analyte separation by capillary electrophoresis versus polyelectrolyte behavior.

    Science.gov (United States)

    Witos, Joanna; Karesoja, Mikko; Karjalainen, Erno; Tenhu, Heikki; Riekkola, Marja-Liisa

    2013-03-01

    [2-(Methacryloyl)oxyethyl]trimethylammonium chloride was successfully polymerized by surface-initiated atom transfer radical polymerization method on the inner surface of fused-silica capillaries resulting in a covalently bound poly([2-(methacryloyl)oxyethyl]trimethylammonium chloride) coating. The coated capillaries provided in capillary electrophoresis an excellent run-to-run repeatability, capillary-to-capillary and day-to-day reproducibility. The capillaries worked reliably over 1 month with EOF repeatability below 0.5%. The positively charged coated capillaries were successfully applied to the capillary electrophoretic separation of three standard proteins and five β-blockers with the separation efficiencies ranging from 132,000 to 303,000 plates/m, and from 82,000 to 189,000 plates/m, respectively. In addition, challenging high- and low-density lipoprotein particles could be separated. The hydrodynamic sizes of free polymer chains in buffers used in the capillary electrophoretic experiments were measured for the characterization of the coatings.

  13. Capillary ion electrophoresis of inorganic anions and uric acid in human saliva using a polyvinyl alcohol coated capillary column and hexamethonium chloride as additive of background electrolyte.

    Science.gov (United States)

    Mori, Masanobu; Yamamoto, Tsukasa; Kaseda, Maki; Yamada, Sachiko; Itabashi, Hideyuki

    2012-03-01

    A combination of polyvinyl alcohol chemically coated capillary (PVA capillary) and background electrolyte (BGE) with ion-pair reagent (hexamethonium dichloride, HMC) was used on capillary ion electrophoresis-UV detection (CIE-UV) for analysis of Br⁻, I⁻, NO₂⁻, NO₃⁻, SCN⁻ and uric acid in human saliva. The PVA capillary prepared in our laboratory minimized electro-osmotic flow (EOF) at the BGE in pH 3-10, and did not affect the UV detection at 210 nm by the PVA-layer on capillary wall. Therefore, use of the PVA capillary was suitable for sensitive UV detection for analyte anions, as well as suppression of protein adsorption. In this study, we optimized the BGE of 10 mM phosphate plus 10 mM HMC with applying a voltage of -15 kV. HMC as an additive to BGE could manipulate the electrophoretic mobility of anions, without electrostatic adsorption to the PVA capillary. The CIE-UV could separate and determine analyte anions in human saliva containing proteins by the direct injection without pretreatments such as dilution or deproteinization within 13 min. The relative standard deviations (n=10) were ranged of 0.5-1.6% in migration times, 2.2-6.8% in peak heights and 2.8-8.4% in peak areas. The limits of detection (S/N=3) were ranged of 3.42-6.87 μM. The peak height of anions in this system was gradually decreased through the successive injections of saliva samples, but the problem was successfully solved by periodically conditioning the PVA capillary. The quantifiability of anions in human saliva samples by the CIE-UV was evaluated through the recoveries by standard addition methods and comparison of other representative analytical methods, as well as identification by ion chromatography (IC). From the anion analyses in 12 different saliva samples, the CIE-UV demonstrated that can obtain obvious differences in concentrations of SCN⁻ between of smoker and non-smoker and those of uric acid between male and female with satisfactory results.

  14. Selectivity in capillary electrokinetic separations

    NARCIS (Netherlands)

    de Zeeuw, R.A; de Jong, G.J.; Ensing, K

    1999-01-01

    This review gives a survey of selectivity modes in capillary electrophoresis separations in pharmaceutical analysis and bioanalysis. Despite the high efficiencies of these separation techniques, good selectivity is required to allow quantitation or identification of a Chemistry and Toxicology, parti

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-01-01

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

  16. 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.

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

    Science.gov (United States)

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

    2016-12-01

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

  18. Capillary electrophoresis and column chromatography in biomedical chiral amino acid analysis.

    Science.gov (United States)

    Waldhier, Magdalena C; Gruber, Michael A; Dettmer, Katja; Oefner, Peter J

    2009-06-01

    Free amino acids are typically quantified as the sum of their enantiomers, because in terrestrial organisms they mainly exist in the left-handed form. However, with increasing understanding of the biological significance of right-handed amino acids interest in enantioselective quantification of amino acids has steadily increased. Initially, electrophoretic and chromatographic methods using chiral (pseudo)-stationary phases or chiral eluents were applied to the separation of amino acid enantiomers. Later, derivatization of amino acids prior to chromatography with chiral reagents gained in popularity, because the diastereomers formed can be resolved on conventional reversed-phase columns. Novel multi-interaction chiral columns turned attention back to direct chiral chromatographic methods. Hyphenation to mass spectrometry has increasingly replaced optical detection because of superior selectivity, although this has not obviated the need for baseline resolution of amino acid enantiomers. Despite the progress made, enantioselective separation and quantification of amino acids remains an analytical challenge owing to frequently incomplete resolution of all naturally occurring enantiomers and insufficient sensitivity for the determination of the trace amounts of D-amino acids typically found in biological fluids and tissues.

  19. Analysis of red inks by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection.

    Science.gov (United States)

    Król, Małgorzata; Gondko, Klaudia; Kula, Agnieszka; Kościelniak, Paweł

    2016-01-01

    A combination of MEKC with a--highly sensitive but not commonly used--LIF detector was tested regarding the possibility of differentiation of red inks. The separation process was conducted in a fused silica capillary (id 50 μm, 60/50 cm total/effective length) in BGE consisting of 40 mM sodium borate, 20 mM SDS and 10% v/v ACN with 30 kV applied. The optimized temperature of storage and capillary was 10 and 25°C, respectively. The samples were prepared using 20 dots (ø 0.5 mm), extracted in 35 μL BGE and diluted with 30 μL of water. The proposed method showed excellent repeatability and reproducibility (RSD (tm ) < 0.8 and < 2.5%, respectively). It was applied to group identification and differentiation of different brands, models, and batches of red printing, stamp, and pen inks. It was demonstrated that differentiation can be performed effectively on the basis of migration times and ratios of peak areas. The high efficiency of the developed method was indicated by discriminating power ranging from 87.3 to 98.8%, for stamp and pen inks, respectively. The results showed that the proposed procedure can be valuable for an objective examination of the red parts of questioned documents.

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

    Science.gov (United States)

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

    2000-07-21

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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. [Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis].

    Science.gov (United States)

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

    2014-04-01

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

  7. Forensic ancestry analysis with two capillary electrophoresis ancestry informative marker (AIM) panels

    DEFF Research Database (Denmark)

    Santos, C; Fondevila, M; Ballard, D

    2015-01-01

    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......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...

  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. 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...... pretreatments and precautions for the determination of organo-mercury compounds. The GC conditions in these determinations where similar to those conditions used for the determination of chlorinated pesticides. The best peak shapes where found using a normal packed column injector, modified with a commercially...... 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....

  10. Stability and Determination of Metamizole Sodium by Capillary Electrophoresis Analysis Combined with Infra-red Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    XIANG Qian; NIU Gang; WU Xian-hua; CHEN Gang

    2007-01-01

    Metamizole sodium was chosen as a representative of unstable analytes for investigation by discusing the effects of oxygen and solvent on its degradation reaction using the capillary electrophoresis technique. A possible degradation mechanism was deduced from the observed behavior and was confirmed by infra-red spectroscopic study. The degradation reaction could be inhibited obviously by methanol instead of water as the solvent of analyte. Under the optimized conditions: separation voltage of 20 kV, and 5 mmol/L disodium hydrogen phosphate and 5 mmol/L borax with 10% methanol(pH 9. 12) as the running buffer, the standard curve of metamizole sodium was linear in a range of 3.77-74.07 mg/L. A satisfactory result was achieved when the technique was used to detect metamizole sodium in tablet.

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

    Directory of Open Access Journals (Sweden)

    Brigitta Simon

    2014-09-01

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

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

    Science.gov (United States)

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

    2013-11-19

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

  13. 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

    2016-08-02

    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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Theory of Cast Formation in Electrophoretic Deposition

    NARCIS (Netherlands)

    Biesheuvel, P. Maarten; Verweij, Henk

    1999-01-01

    The rate of cast formation in electrophoretic deposition is described by a combination of the equation of continuity for the suspension phase with expressions for the particle velocity and the movement of the cast-suspension boundary. The assumptions necessary to arrive at the well-known equations o

  19. 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.

  20. Application of capillary electrophoresis in analysis of intact mammalian cells%毛细管电泳在完整哺乳动物细胞分析中的应用

    Institute of Scientific and Technical Information of China (English)

    张璐; 屈锋; 娄蓓蕾

    2012-01-01

    Cell is the basic structural and functional unit of human body. The research of cells' structure, function and behavior is very important. Capillary electrophoresis (CE) is a powerful tool for the separation and analysis, the application of which in cell analysis has progressed significantly. In this paper, the developments of CE applied in the intact mammalian cell analysis are reviewed, which consist of cell population and single cell analysis. The erythrocyte, boar sperm, HeLa cells, SH-SY5Y cells, Caco-2 cells, K562 cells and rat cerebellar granule cells are involved in this review. The methods and conditions for the intact mammalian cell analysis are summarized. In addition, the problems caused by the breakage, aggregation, sedimentation , adsorption and electrophoretic heterogeneity of the cell in the intact mammalian cell analysis by CE are discussed, and the corresponding solutions are introduced. Also, the future research trends are presented. Forty nine papers in all are reviewed.%作为人体形态结构、生理功能和生长发育的基本单位,细胞的结构功能及行为分析具有重要的研究价值.毛细管电泳作为日渐成熟的微量分析技术在细胞分析及应用方面已取得显著进展.本文综述了毛细管电泳在完整哺乳动物细胞分析中的应用,包括群体细胞分析和完整单细胞分析.所述内容涉及血红细胞、公猪精子、人宫颈癌细胞、人神经母细胞瘤细胞、人结直肠腺癌细胞、人慢性髓系白血病细胞以及鼠小脑颗粒细胞.总结了完整哺乳动物细胞分析的毛细管电泳方法和条件,归纳分析了完整细胞分析中存在的细胞破碎、聚集、沉降、吸附及电泳异质性等关键问题及解决方法.对毛细管电泳在细胞分析方面未来的应用方向进行了展望.综述文献49篇.

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

    Science.gov (United States)

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

    2008-01-01

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

  2. Analysis of reducing carbohydrates by reductive tryptamine derivatization prior to micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Andersen, Keld E; Bjergegaard, Charlotte; Sørensen, Hilmer

    2003-12-03

    A micellar electrokinetic capillary chromatography method for determination of low molecular weight carbohydrates (dp 1-2) with an unbound carbonyl group as in aldoses or other reducing carbohydrates has been developed. Reductive amination of aldoses on the carbonyl group using tryptamine introduced a chromophor system to the carbohydrates enabling their sensitive UV detection at 220 nm and identification based on the indole group using diode array detection. Twelve carbohydrates including pentoses (d-ribose, l-arabinose, and d-xylose), hexoses (d-glucose, d-mannose, and d-galactose), deoxy sugars (l-rhamnose and l-fucose), uronic acids (d-glucuronic acid and d-galacturonic acid), and disaccharides (cellobiose and melibiose) are included in the study, using d-thyminose (2-deoxy-d-ribose) as the internal standard. Detection of all 12 carbohydrates is performed within 30 min. Linearity with correlation coefficients from 0.9864 to 0.9992 was found in the concentration range of 25-2500 micromol/L for all carbohydrates; the relative standard deviation on the migration times was between 0.27 and 0.80 min, and limits of quantification and limits of determination were in the picomole range.

  3. 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.

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

    Institute of Scientific and Technical Information of China (English)

    王清江; 丁飞; 李辉; 何品刚; 方禹之

    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.

  5. 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.

  6. Capillary gas chromatographic analysis of nerve agents using large volume injections. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Deinum, T.; Nieuwenhuy, C.

    1994-11-01

    The procedure developed at TNO-Prins Maurits Laboratory (TNO-PML) for the verification of intact organophosphorus chemical warfare agents in water samples was improved. The last step in this procedure, the laborious and non-reproducible transfer of an ethyl acetate extract onto a Tenax-adsorption tube followed by thermal desorption of the Tenax-tube, was replaced by large volume injection of the extract onto a capillary gas chromatographic system. The parameters controlling the injection of a large volume of an extract (200 ul) were investigated and optimized. As ethyl acetate caused severe problems, potential new solvents were evaluated. With the improved procedure, the nerve agents sarin, tabun, soman, diisopropyl fluorophosphate (DFP) and VX could be determined in freshly prepared water samples at pg/ml (ppt) levels. The fate of the nerve agents under study in water at two pH`s (4.8 and 6) was investigated. For VX, the pH should be adjusted before extraction. Moreover, it is worthwhile to acidify water samples to diminish hydrolysis.

  7. 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…

  8. 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

  9. Linear stability analysis of immiscible two-phase flow in porous media with capillary dispersion and density variation

    Science.gov (United States)

    Riaz, Amir; Tchelepi, Hamdi A.

    2004-12-01

    Linear stability analysis of immiscible displacements is carried out for both viscously and gravitationally unstable two-phase flows in porous media with very large adverse viscosity ratios. Capillary dispersion is the proper dissipative mechanism in this case which sets both the preferred length scale and the band width of the spectrum of unstable length scales. The growth rate, the most dangerous and the cutoff wavenumbers, all scale linearly with the capillary number. We show that the instability is governed by fluid properties across the shock rather than those across the full Buckley-Leverett profile. The shock total mobility ratio provides a sufficient condition for the onset of instability; however, it is not an appropriate criterion for predicting the magnitude of the growth rate, particularly for large viscosity ratios. The details of the relative permeability functions are observed to have a significant influence on the stability characteristics. For neutrally buoyant flows the maximum growth rate scales linearly with the viscosity ratio while the most dangerous and the cutoff wavenumbers scale with the square root of the viscosity ratio. In the case of displacements with density contrast, the maximum growth rate scales with the square of the unstable gravity number while the most dangerous and the cutoff wavenumbers scale with an exponent of 1.2, for all viscosity ratios. A marginal stability curve is computed for stable and unstable regions in the parameter space of the viscosity ratio and the gravity number. It is found that flows with unstable viscosity contrasts are more readily stabilized with buoyancy as compared to the viscous stabilization of gravitationally unstable flows.

  10. DNA typing by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, N.

    1997-10-08

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

  11. Nitromethane as solvent in capillary electrophoresis.

    Science.gov (United States)

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

    2005-06-24

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

  12. 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...

  13. [The rapid analysis of polychlorinated quaterphenyls in blood using different diameter capillary column with the high-resolution gas chromatograph high-resolution mass spectrometer].

    Science.gov (United States)

    Yasutake, Daisuke; Ashizuka, Yuki; Hori, Tsuguhide; Kurokawa, Youichi; Kajiwara, Jumboku; Hirata, Teruaki; Ishiguro, Yasuhisa; Iida, Takao; Uchi, Hiroshi; Furue, Masutaka

    2011-04-01

    The polychlorinated quaterphenyl (PCQ) concentrations in blood are important discriminative parameters in yusho patient. In this study, a rapid analytical method for PCQ using different diameter capillary column (rapid-Rtx65TG) with high-resolution gas chromatograph high-resolution mass spectrometer (HRGC/HRMS) instead of the gas chromatograph electron capture detector (ECD/GC) was developed. Using different diameter capillary columns, the analysis time of the HRGC/HRMS was drastically shortened, and the detection sensitivity was improved. In the rapid-Rtx65TG column, a small-bore capillary column (length 1m, I.D. 0.1mm) was connected with the inlet side of the GC, and behind that column, a large-bore capillary column (length 15mm, I.D. 0.53mm) for octadecachloroquaterphenyl (ODCQ) analysis was connected. In the HRGC/HRMS measurement of ODCQ by the rapid-Rtx65TG column, the minimum limit of detection for the apparatus was 0.4 pg, and the minimum limit of determination for the blood was 0.008 ppb. On ECD/GC in the conventional method and HRGC/HRMS in this study, the PCQ concentration in blood including yusho patients and yusho suspected persons was almost equivalent.

  14. Leukocytes in capillary flow.

    Science.gov (United States)

    Schmid-Schönbein, G W; Lee, J

    1995-01-01

    During disease, the flow of blood cells through the capillary network is one of the most perilous events in the microcirculation. Capillary distensibility, cytoplasmic activity of endothelial cells, red cells and leukocytes play an important role in capillary perfusion. Occlusion of capillaries is one of the early signs of vascular failure and is encountered in many different conditions and organs. Adhesion of leukocytes to the endothelium via expression of membrane adhesion molecules leads to microvascular entrapment with capillary occlusion.

  15. Analysis of phosphate and phosphate containing headgroups enzymatically cleaved from phospholipids of Bacillus subtilis by capillary electrophoresis.

    Science.gov (United States)

    Bierhanzl, Václav Matěj; Riesová, Martina; Taraba, Lukáš; Čabala, Radomír; Seydlová, Gabriela

    2015-09-01

    A new, fast, selective, and reliable capillary electrophoresis method has been developed for analysis of selected phosphoesters (phosphoserine, phosphoethanolamine, phosphoglycerol) and phosphate. The method is based on separation of specific phosphate containing headgroups (phosphoesters) which are cleaved from the glycerol skeleton of a phospholipid by a regioselective enzyme (phospholipase C). Analysis of intact phospholipids with the same polar headgroup but different fatty acids shows that fatty acid composition has a high impact on separation of phospholipids, so analysis of separated polar headgroups, which avoids this influence, represents a much more suitable approach for phospholipid class research. Optimization of method parameters results in running buffers of relatively narrow pH interval (pH about 10) where all phosphoesters are separated. Further method validation has shown that direct UV detection has a sufficient detection limit for all analytes to perform suitable analyses of cell membrane lipids. The optimized method was tested on the lysate of cell membrane of Bacillus subtilis, where all analytes were determined.

  16. 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.

  17. 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.

  18. Finding the "bio" in biobased products: electrophoretic identification of wheat proteins in processed products.

    Science.gov (United States)

    Robertson, George H; Hurkman, William J; Cao, Trung K; Tanaka, Charlene K; Orts, William J

    2010-04-14

    Verification of the biocontent in biobased or "green" products identifies genuine products, exposes counterfeit copies, supports or refutes content claims, and ensures consumer confidence. When the biocontent includes protein, elemental nitrogen analysis is insufficient for verification since non-protein, but nitrogen-rich, content also may be present. However, the proteins can be extracted, separated by electrophoretic methods, and detected by UV absorption, protein stain, or immunoblotting. We utilized capillary zone electrophoresis (CZE) to separate proteins in a gliadin fraction that had been dissolved in aqueous ethanol (70%) and polyacrylamide gel electrophoresis (PAGE) to separate proteins in a gliadin-plus-glutenin fraction that had been dissolved in water containing both sodium dodecyl sulfate (SDS) and a reducing agent, dithiothreitol (DTT). We sought to verify the presence of these wheat grain proteins in wheat bread, a wheat flake cereal, wheat beer, and an enclosure for an antique automobile ignition coil reputed to contain wheat gluten. Proteins extracted from commercial wheat, corn, and soy flours served as standards, and proteins from heat-altered wheat served as process condition references. This approach successfully identified wheat proteins in these products especially if the process temperature did not exceed 120 degrees C. Above this temperature attenuation was nearly complete for proteins analyzed by CZE, but wheat-like patterns could still be recognized by one- and two-dimensional PAGE. Immunoblots reacted with grain-specific antibodies confirmed the identities of the cereal component especially when the protein pattern was greatly altered by thermal modification, specific protein adsorption, or protein digestion. In addition to verifying that wheat proteins are present, the complementary use of these methods can reveal whether whole wheat gluten or merely an alcohol-soluble fraction had been used in the specific product and indicate the

  19. 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.

  20. 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)

  1. Amine Analysis Using AlexaFluor 488 Succinimidyl Ester and Capillary Electrophoresis with Laser-Induced Fluorescence

    Directory of Open Access Journals (Sweden)

    Christian G. Kendall

    2015-01-01

    Full Text Available Fluorescent probes enable detection of otherwise nonfluorescent species via highly sensitive laser-induced fluorescence. Organic amines are predominantly nonfluorescent and are of analytical interest in agricultural and food science, biomedical applications, and biowarfare detection. Alexa Fluor 488 N-hydroxysuccinimidyl ester (AF488 NHS-ester is an amine-specific fluorescent probe. Here, we demonstrate low limit of detection of long-chain (C9 to C18 primary amines and optimize AF488 derivatization of long-chain primary amines. The reaction was found to be equally efficient in all solvents studied (dimethylsulfoxide, ethanol, and N,N-dimethylformamide. While an organic base (N,N-diisopropylethylamine is required to achieve efficient reaction between AF488 NHS-ester and organic amines with longer hydrophobic chains, high concentrations (>5 mM result in increased levels of ethylamine and propylamine in the blank. Optimal incubation times were found to be >12 hrs at room temperature. We present an initial capillary electrophoresis separation for analysis using a simple micellar electrokinetic chromatography (MEKC buffer consisting of 12 mM sodium dodecylsulfate (SDS and 5 mM carbonate, pH 10. Limits of detection using the optimized labeling conditions and these separation conditions were 5–17 nM. The method presented here represents a novel addition to the arsenal of fluorescent probes available for highly sensitive analysis of small organic molecules.

  2. A unified mathematical theory of electrophoretic processes

    Science.gov (United States)

    Bier, M.; Palusinski, O. A.; Mosher, R. A.; Graham, A.; Saville, D. A.

    1983-01-01

    A mathematical theory is presented which shows that each of the four classical electrophoretic modes (zone electrophoresis, moving boundary electrophoresis, isotachophoresis, and isoelectric focusing) is based on the same general principles and can collectively be described in terms of a single set of equations. This model can predict the evolution of the four electrophoretic modes as a function of time. The model system is one-dimensional, neglecting the effects of electroosmosis, temperature gradients, and any bulk flows of liquid. The model is based on equations which express the components' dissociation equilibria, the mass transport due to electromigration and diffusion, electroneutrality, and the conservation of mass and charge. The model consists of a system of coupled partial differential and nonlinear algebraic equations which can be solved numerically by use of a computer. The versatility of this model was verified using an example of a three-component system containing cacodylate, tris hydroxylmethylaminomethane, and histidine. Results show that this model not only correctly predicts the characteristic features of each electrophoretic mode, but also gives details of the concentration, pH, and conductivity profiles not easily amenable to direct experimental measurement.

  3. 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.

  4. 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.

  5. Capillary high-performance liquid chromatography/mass spectrometric analysis of proteins from affinity-purified plasma membrane.

    Science.gov (United States)

    Zhao, Yingxin; Zhang, Wei; White, Michael A; Zhao, Yingming

    2003-08-01

    Proteomics analysis of plasma membranes is a potentially powerful strategy for the discovery of proteins involved in membrane remodeling under diverse cellular environments and identification of disease-specific membrane markers. A key factor for successful analysis is the preparation of plasma membrane fractions with low contamination from subcellular organelles. Here we report the characterization of plasma membrane prepared by an affinity-purification method, which involves biotinylation of cell-surface proteins and subsequent affinity enrichment with strepavidin beads. Western blotting analysis showed this method was able to achieve a 1600-fold relative enrichment of plasma membrane versus mitochondria and a 400-fold relative enrichment versus endoplasmic reticulum, two major contaminants in plasma membrane fractions prepared by conventional ultracentrifugation methods. Capillary-HPLC/MS analysis of 30 microg of affinity-purified plasma membrane proteins led to the identification of 918 unique proteins, which include 16.4% integral plasma membrane proteins and 45.5% cytosol proteins (including 8.6% membrane-associated proteins). Notable among the identified membrane proteins include 30 members of ras superfamily, receptors (e.g., EGF receptor, integrins), and signaling molecules. The low number of endoplasmic reticulum and mitochondria proteins (approximately 3.3% of the total) suggests the plasma membrane preparation has minimum contamination from these organelles. Given the importance of integral membrane proteins for drug design and membrane-associated proteins in the regulation cellular behaviors, the described approach will help expedite the characterization of plasma membrane subproteomes, identify signaling molecules, and discover therapeutic membrane-protein targets in diseases.

  6. 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.

  7. 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

    2015-02-06

    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

  8. 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.

  9. Capillary electrophoresis using core-based hyperbranched polyethyleneimine (CHPEI) static-coated capillaries.

    Science.gov (United States)

    Boonyakong, Cheerapa; Tucker, Sheryl A

    2009-10-01

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

  10. Electrophoretic separation techniques and their hyphenation to mass spectrometry in biological inorganic chemistry.

    Science.gov (United States)

    Holtkamp, Hannah; Grabmann, Gerlinde; Hartinger, Christian G

    2016-04-01

    Electrophoretic methods have been widely applied in research on the roles of metal complexes in biological systems. In particular, CE, often hyphenated to a sensitive MS detector, has provided valuable information on the modes of action of metal-based pharmaceuticals, and more recently new methods have been added to the electrophoretic toolbox. The range of applications continues to expand as a result of enhanced CE-to-MS interfacing, with sensitivity often at picomolar level, and evolved separation modes allowing for innovative sample analysis. This article is a followup to previous reviews about CE methods in metallodrug research (Electrophoresis, 2003, 24, 2023-2037; Electrophoresis, 2007, 28, 3436-3446; Electrophoresis, 2012, 33, 622-634), also providing a comprehensive overview of metal species studied by electrophoretic methods hyphenated to MS. It highlights the latest CE developments, takes a sneak peek into gel electrophoresis, traces biomolecule labeling, and focuses on the importance of early-stage drug development.

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

    Science.gov (United States)

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

    2005-09-01

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

  12. 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 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.

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

    Science.gov (United States)

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

    2014-02-01

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

  14. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    DEFF Research Database (Denmark)

    Franzen, Ulrik; Østergaard, Jesper

    2012-01-01

    Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary...... electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability...... of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization...

  15. Comparative analysis of the possibility of applying low-melting metals with the capillary-porous system in tokamak conditions

    Science.gov (United States)

    Lyublinski, I. E.; Vertkov, A. V.; Semenov, V. V.

    2016-12-01

    The use of capillary-porous systems (CPSs) with liquid Li, Ga, and Sn is considered as an alternative for solving the problem of creating plasma-facing elements (PFEs) of the fusion neutron source (FNS) and the DEMO-type reactor. The main advantages of CPSs with liquid metal compared with hard materials are their stability with respect to the degradation of properties in tokamak conditions and capability of surface self-restoration. The evaluation of applicability of liquid metals is performed on the basis of the analysis of their physical and chemical properties, the interaction with the tokamak plasma, and constructive and process features of in-vessel elements with CPSs implementing the application of these metals in a tokamak. It is shown that the upper limit of the PFE working temperature for all low-melting metals under consideration lies in the range of 550-600°C. The decisive factor for PFEs with Li is the limitation on the admissible atomic flux into plasma, while for those with Ga and Sn it is the corrosion resistance of construction materials. The upper limit of thermal loads in the steady-state operating mode for the considered promising PFE design with the use of Li, Ga, and Sn is close to 18-20 MW/m2. It is seen from the analysis that the use of metals with a low equilibrium vapor pressure of (Ga, Sn) gives no gain in extension of the region of admissible working temperatures of PFEs. However, with respect to the totality of properties, the possibility of implementing the self-restoration and stabilization effect of the liquid surface, the influence on the plasma discharge parameters, and the ability to protect the PFE surface in conditions of plasma perturbations and disruption, lithium is the most attractive liquid metal to create CPS-based PFEs for the tokamak.

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

    Science.gov (United States)

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

    2012-01-01

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

  17. 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.

  18. Separation of Proteins by Electrophoretic Affinity Chromatography

    Institute of Scientific and Technical Information of China (English)

    邺韶骅; 刘铮; 丁富新; 袁乃驹

    1999-01-01

    A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed,Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the central compartments.The presence of an electric field accelerated the migration of proteins inside the gel matrix during adsorption and descrption processes,This led to the increase of the overall speed of separation,The present study was focused on the effect of the strength of the electric field on adsorption and desorption processes.

  19. Validation of a Serum Analysis Method to Analyze Antihistamines by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    J. Peris-Vicente

    2014-01-01

    Full Text Available The validation of an electrophoresis-based analytical method to quantify 17 antihistamines in pharmaceutical formulations and serum is described. Then, whether the methodology provides true values with low uncertainty and is able to detect the concentration range level of analyte usually found in the matrix was evaluated. The analytical method was validated following the recommendations of an official guide to provide more reliability to the results. The ICH Harmonized Tripartite Guideline was selected because it was especially developed for analysis of drugs. The guide and the following required validation parameters, selectivity, calibration range, linearity, limit of detection, limit of quantification, inter- and intraday accuracy and precision, and robustness, were described. The method was inexpensive, fast, simple, environmentally friendly, and useful for routine analysis. The methodology was successfully validated and applied to commercial pharmaceutical formulations and spiked blank serum samples.

  20. 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.

  1. 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.

  2. Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection.

    Science.gov (United States)

    Greguš, Michal; Foret, František; Kubáň, Petr

    2015-02-01

    The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics.

  3. A Local Condensation Analysis Representing Two-phase Annular Flow in Condenser/radiator Capillary Tubes

    Science.gov (United States)

    Karimi, Amir

    1991-01-01

    NASA's effort for the thermal environmental control of the Space Station Freedom is directed towards the design, analysis, and development of an Active Thermal Control System (ATCS). A two phase, flow through condenser/radiator concept was baselined, as a part of the ATCS, for the radiation of space station thermal load into space. The proposed condenser rejects heat through direct condensation of ATCS working fluid (ammonia) in the small diameter radiator tubes. Analysis of the condensation process and design of condenser tubes are based on the available two phase flow models for the prediction of flow regimes, heat transfer, and pressure drops. The prediction formulas use the existing empirical relationships of friction factor at gas-liquid interface. An attempt is made to study the stability of interfacial waves in two phase annular flow. The formulation is presented of a stability problem in cylindrical coordinates. The contribution of fluid viscosity, surface tension, and transverse radius of curvature to the interfacial surface is included. A solution is obtained for Kelvin-Helmholtz instability problem which can be used to determine the critical and most dangerous wavelengths for interfacial waves.

  4. 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.

  5. Role of phospholipids in drug-LDL bindings as studied by high-performance frontal analysis/capillary electrophoresis.

    Science.gov (United States)

    Kuroda, Yukihiro; Watanabe, Yoshinori; Shibukawa, Akimasa; Nakagawa, Terumichi

    2003-01-15

    The binding study between basic drugs ((S)-verapamil (VER) and (S)-propranolol (PRO)) and phospholipid liposomes was performed by using high-performance frontal analysis/capillary electrophoresis (HPFA/CE) in order to investigate the effect of oxidative modification of low-density lipoprotein (LDL) upon drug-binding affinity from molecule-based viewpoint. 1-Palmitoyl-2-oleoyl-phosphatidylcholine (POPC, 16:0, 18:1), 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC, 16:0, 18:2), dilauloyl-phosphatidylcholine (DLaPC, 12:0, 12:0), 1-palmitoyl-2-oleoyl-phosphatidyl-glycerol (POPG, 16:0, 18:1), and 1-palmitoyl-sn-glycero-3-phosphocholine (monoPPC, 16:0) were used to prepare the model liposomes. At physiological pH (pH 7.4), the model liposome prepared from POPG+POPC had negative net charges, while the total net charge of the other model liposomes (POPC liposome, PLPC liposome, DLaPC liposome, and monoPPC+POPC liposome) was zero. The drug and the model liposome mixed solutions were subjected to HPFA/CE, and the total binding affinities (nK) were calculated. The nK values of VER and PRO to POPG+POPC liposome were more than six and 10 times higher than those of other liposomes, respectively. On the other hand, the nK values of the model drugs to POPC liposome, PLPC liposome, DLaPC liposome and monoPPC+POPC liposome showed small differences less than twice. These results indicate that the electrostatic interaction plays an important effect on drug-liposome binding, and suggest that the increase in the negative charge of LDL phospholipids gives more significant effect on the drug-binding affinity of the basic drugs than the acyl-chain structure.

  6. 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

  7. Analysis of urinary N-acetyl-beta-glucosaminidase by capillary zone electrophoresis.

    Science.gov (United States)

    Friedberg, M; Shihabi, Z K

    1997-07-18

    N-Acetyl-beta-glucosaminidase (NAG), a glycosidase enzyme, present in serum, urine and the renal lysosomes is utilized clinically as an early marker for renal damage preceding the elevation of both blood urea nitrogen and creatinine. NAG is analyzed by CE after incubation of urine samples with the synthetic substrate methylumbelliferyl-beta-D-glucosaminide. The reaction mixture is introduced directly into the instrument without further treatment. The released reaction product, 4-methyl-umbelliferone, is separated at 13.2 kV in a 400 mM borate buffer, pH 8.1. Detection was achieved with either ultraviolet absorption or with fluorescence. The fluorescence detection was more sensitive and gave cleaner electropherograms. The CZE method correlated well with an automated kinetic fluorescent assay. 4-Methyl-umbelliferone conjugated to different substrates is used in the analysis of many enzymes involved in the inborn errors of metabolism.

  8. Cyclic electrophoretic and chromatographic separation methods

    NARCIS (Netherlands)

    Eijkel, Jan C.T.; Berg, van den Albert; Manz, Andreas

    2004-01-01

    A review is given of the application of cyclic analytical methods in capillary electroseparation (CE) and liquid chromatography (LC) systems. Cyclic methods have been used since the early sixties in chromatographic systems to overcome pressure limitations to resolution. From the early nineties on th

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

    Directory of Open Access Journals (Sweden)

    G. Enne

    2011-03-01

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

  10. Applications of capillary electrophoresis electrospray ionization mass spectrometry in glycosaminoglycan analysis.

    Science.gov (United States)

    Zamfir, Alina D

    2016-04-01

    Proteoglycans (PGs) represent a class of heavily glycosylated proteins distributed in the extracellular matrix, connective tissues, and on the surface of many cell types where, as functional molecules, regulate important biological processes. Structurally, PGs consist of a core protein linked to glycosaminoglycan (GAG) chains, which basically determine the properties and activities of PGs. In view of the structural complexity of GAGs and the existing correlation between this structure and PG functions, systematic efforts are invested into development of analytical methods for GAG characterization. Although less popular and of higher technical difficulty than liquid-based chromatographic methods, CE coupled with ESI MS contributed lately an important progress to glycosaminoglycomics field. In this review article, the most significant CE ESI MS and MS/MS applications in GAG research are highlighted and critically assessed. The advantages and the limitations of each concept as well as the possible further methodological refinements are also concisely discussed. Finally, the review presents the perspectives of CE ESI MS in GAG analysis along with the objectives, which still need to be reached in the near future.

  11. In-tube solid-phase microextraction coupled by in valve mode to capillary LC-DAD: Improving detectability to multiresidue organic pollutants analysis in several whole waters.

    Science.gov (United States)

    Campíns-Falcó, P; Verdú-Andrés, J; Sevillano-Cabeza, A; Herráez-Hernández, R; Molins-Legua, C; Moliner-Martinez, Y

    2010-04-16

    A simple and fast capillary chromatographic method has been developed to identify and quantify organic pollutants at sub-ppb levels in real water samples. The major groups of pesticides (organic halogens, organic phosphorous, and organic nitrogen compounds), some hydrocarbons (polycyclic aromatic hydrocarbons), phthalates and some phenols such as phenol and bisphenol A (endocrine disruptors) were included in this study. The procedure was based on coupling, in-tube solid-phase microextraction (IT-SPME) by using a conventional GC capillary column (95% methyl-5% phenyl substituted backbone, 80cmx0.32mm i.d., 3microm film thickness) in the injection valve to capillary liquid chromatography with diode array detection. A comparative study between the IT-SPME manifold and a column-switching device using a C(18) column (35mmx0.5mm i.d., 5microm particle size) has been performed. The IT-SPME procedure was optimal, it allows reaching limits of detection (LODs) between 0.008 and 0.2microg/L. No matrix effect was found and recoveries between 70 and 116% were obtained. The precision of the method was good, and the achieved intra- and inter-day variation coefficients were between 2 and 30%. This procedure has been applied to the screening analysis of 28 compounds in whole waters from several points of the Mediterranean coast (Valencia Community, Spain).

  12. Single strand conformation polymorphism analysis of candidate genes for reliable identification of alleles by capillary array electrophoresis.

    Science.gov (United States)

    We investigated the reliability of capillary array electrophoresis-SSCP to determine if it can be used to identify novel alleles of candidate genes in a germplasm collection. Both strands of three different size fragments (160 bp, 245 pb and 437 bp) that differed by one or more nucleotides in sequen...

  13. Analysis of volatile organic compounds in water by dynamic stripping, thermal desorption, cryofocusing, and capillary gas chromatography (journal version)

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, S.A.

    1988-01-01

    A dynamic headspace procedure developed for the determination of volatile organic compounds (VOCs) in water is described. The VOCs are purged from a water sample with an inert gas, transferring them to a tube packed with Tenax adsorbent. The adsorbent tube, or trap, is thermally desorbed, the analytes cryofocused, and subsequently transferred to a capillary column gas chromatograph.

  14. A simplified electrophoretic system for determining molecular weights of proteins.

    Science.gov (United States)

    Manwell, C

    1977-09-01

    Electrophoresis of 31 different proteins in commercially prepared polyacrylamide gradient gels, Gradipore, yields a linear relationship between a hypothetical limiting pore size (the reciprocal of a limiting gel concentration, GL) and the cube root of the mol.wt., over the range 13 500-9000 000. A regression analysis of these data reveals that 98.6% of all variability in 1/GL is explained by the molecular weight, and this degree of accuracy compares favourably with existing methods for the determination of molecular weight by retardation of mobility in polyacrylamide. This new procedure has the additional advantages that molecular-weight standards can be obtained from readily available body fluids or tissue extracts by localizing enzymes and other proteins by standard histochemical methods, and that the same electrophoretic system can be used in determining molecular weights as is used in routine surveys of populations for individual and species variation in protein heterogeneity.

  15. Electrophoretic separation of lunar soils in a space manufacturing facility

    Science.gov (United States)

    Dunning, J. D.; Snyder, R. S.

    1981-01-01

    The feasibility of electrophoretic separation of lunar soil into its mineral constituents is discussed in this paper. The process and its applicability to lunar soil separation are considered in light of the special requirements of a space manufacturing effort. Data generated in studies at NASA-Marshall Space Flight Center, which assess the efficiency of electrophoretic separation of lunar soil, are discussed and evaluated.

  16. 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.

  17. Fast capillary electrophoresis-time-of-flight mass spectrometry using capillaries with inner diameters ranging from 75 to 5 μm.

    Science.gov (United States)

    Grundmann, Marco; Matysik, Frank-Michael

    2011-04-01

    Fast electrophoretic separations in fused silica capillaries (CE) coupled to time-of-flight mass spectrometry (TOF-MS) are presented. CE separations of the model analytes (epinephrine, norepinephrine, dopamine, histidine, and isoproterenol) under conditions of high electric field strengths of up to 1.25 kV cm(-1) are completed in 20 s. Coupling of CE with TOF-MS is accomplished using a coaxial sheath liquid electrospray ionization interface. The influence of parameters inherent to the interface and their effects, including suction pressure and dilution, are discussed. In addition to standard capillaries of 75 and 50 μm inner diameter (ID), separations in capillaries with IDs of 25, 15, and 5 μm have been successfully applied to this setup. The analytical performance is compared over this range of capillary dimensions, and both advantages and disadvantages are discussed.

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

    Science.gov (United States)

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

    2014-09-05

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

  19. 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

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

    Science.gov (United States)

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

    2012-10-01

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

  1. 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.

  2. Analysis of coal tar polycyclic aromatic hydrocarbon LC-fractions by capillary SFC on a liquid crystalline stationary phase

    Energy Technology Data Exchange (ETDEWEB)

    Kithinji, J.P.; Raynor, M.W.; Egia, B.; Davies, I.L.; Bartle, K.D.; Clifford, A.A. (University of Leeds, Leeds (UK). School of Chemistry)

    1990-01-01

    Supercritical fluid chromatography (SFC) on a capillary column coated with a smectic mesomorphic crystalline phase is shown to exhibit a typical turnover effect (retention versus column temperature) for polycyclic aromatic hydrocarbons (PAHs) at lower temperatures than are found on a methylpolysiloxane phase. Liquid chromatography is used to separate various fractions from a coal tar, which are analyzed by high resolution capillary SFC. Different density and temperature programs were investigated to optimize the separations. Simultaneous density and temperature programs gave the best results, and this is thought to be due to increased solute diffusion coefficients which yield highly efficient separations for the high molecular weight polycyclic aromatic hydrocarbons. The separation mechanism is based on the shape of the liquid crystalline phase, solubility, volatility, and molecular geometry of the PAHs.

  3. 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.

  4. 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.

  5. Multidimensional capillary electrophoresis.

    Science.gov (United States)

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

    2015-01-01

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

  6. Pulsed-field capillary electrophoresis: optimizing separation parameters with model mixtures of sulfonated polystyrenes.

    Science.gov (United States)

    Sudor, J; Novotny, M V

    1994-07-01

    The electrophoretic transport of high molecular weight charged solutes, both flexible and stiff polymers, has been studied by capillary electrophoresis under constant-field and pulsed-field conditions. Sulfonated polystyrenes were used as model solutes in different entangled polymer solutions. First, changes of the end-to-end distance vectors of flexible polymers were examined through the mobility/potential-gradient curves. Under pulsed-field conditions, the influence of different pulse shapes, frequencies, and amplitudes of forward and backward pulses on the electrophoretic mobilities of model solutes was studied. Resolution of the mixture components was strongly affected by changes in frequency of both sine-wave and square-wave pulses. The experimental results obtained under pulse-field conditions are roughly in agreement with the existing theories of electrophoretic transport.

  7. 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...

  8. 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.

  9. Simultaneous determination of the beta-blocker atenolol and several complementary antihypertensive agents in pharmaceutical formulations and urine by capillary zone electrophoresis.

    Science.gov (United States)

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

    1998-10-01

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

  10. 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.

  11. High-throughput analysis of bergamot essential oil by fast solid-phase microextraction-capillary gas chromatography-flame ionization detection.

    Science.gov (United States)

    Tranchida, Peter Quinto; Presti, Maria Lo; Costa, Rosaria; Dugo, Paola; Dugo, Giovanni; Mondello, Luigi

    2006-01-20

    The advantages of using a narrow-bore column in headspace solid-phase microextraction-gas chromatographic (HS-SPME-GC) analysis are investigated. An automated rapid HS-SPME-GC method for the determination of volatile compounds in a complex sample (bergamot essential oil) was developed. A low-capacity (7 microm) SPME fibre was employed, enabling a short equilibration time (15 min). The absorbed volatile compounds were then separated in 12.5 min on a 10 m x 0.1 mm I.D. capillary. The fast GC method was characterized by relatively moderate GC parameters (head pressure: 173 kPa; temperature program rate: 12 degrees C/min). The employment of the low-capacity fibre also suited the reduced sample capacity of the capillary employed, hence column overloading was avoided. Analytical repeatibility was determined in terms of retention times (maximum RSD: 0.32%) and peak areas (maximum RSD: 9.80%). The results obtained were compared to those derived from a conventional HS-SPME-GC (a 30 microm SPME fibre and 0.25 mm I.D. capillary were used) application on the same sample. In this respect, a great reduction of analytical time was obtained both with regard to the conventional SPME equilibration and GC run times, which both required 50 min. Peak resolution was altogether comparable in both applications. Although a slight loss in terms of sensitivity was observed in the rapid approach (generally within the 25-50% range), this did not impair the detection of all peaks of interest. Finally, the selectivities of the 30 and 7 microm fibres were evaluated and, as expected, these were in good agreement.

  12. A Microfluidic Platform for Interfacial Electrophoretic Deposition

    Science.gov (United States)

    Joung, Young Soo; Moran, Jeffrey; Jones, Andrew; Bailey, Eric; Buie, Cullen

    2014-11-01

    Composite membranes of hydrogel and carbon nanotubes (CNTs) are fabricated using electrophoretic deposition (EPD) at the interface of two immiscible liquids in microfluidic channels. Microfluidic channels, which have two parallel electrodes at the walls, are used to create electric fields across the interface of oil and water continuously supplied into the channels. Depending on the Reynolds (Re) and Weber (We) numbers of oil and water, we observe different formations of the interface. Once we find the optimal Re and We to create a planar interface in the channel, we apply an electric field across the interface for EPD of CNTs and/or silver (Ag) nanorods dispersed in water. During EPD, particles migrate to the oil/water interface, where cross-linking of polymers is induced to form composite hydrogel membranes. Properties of the composite hydrogel films are controlled by electric fields, CNT concentrations, and both Re and We numbers, allowing for continuous production. This fabrication method is effective to create composite polymer membranes placed in microfluidic devices with tunable electrical, mechanical, and biological properties. Potential applications include fabrication of doped hydrogels for drug delivery, conductive hydrogels for biological sensing, and electron permeable membranes for water splitting and osmotic power generation.

  13. 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.

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

    Science.gov (United States)

    Ghosal, Sandip

    2004-01-01

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

  15. 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%.

  16. A novel method for Co(Ⅱ) and Cu(Ⅱ) analysis by capillary electrophoresis with chemiluminescence detection

    Institute of Scientific and Technical Information of China (English)

    Xiao Ming Guo; Xiang Dong Xu; Hui Jing Zhang; Yong Gang Hu; Jie Zhang

    2007-01-01

    Based on the fact that some metal ions can catalyze the chemiluminescence (CL) reaction of luminol with K3Fe(CN)6, a novel capillary electrophoresis CL method was developed for the determination of Co(Ⅱ) and Cu(Ⅱ). The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/L α-HIBA (adjusted to pH 4.8 by Hac solution). The post-capillary reagent was 2.0 mmol/L K3Fe(CN)6 which was adjusted to pH 13.0 by NaOH solution. Under the optimum conditions, the detection limits (S/N = 3) for Co(Ⅱ) and Cu(Ⅱ) were 7.5 × 10-11 mol/L and 7.5 × 10-9 mol/L, with the linear range of 7.5 × 10-9 mol/L to 1.0 × 10-6 mol/L and 7.5 × 10-8 mol/L to 5.0 × 10-5 mol/L,respectively.

  17. Highly sensitive transient isotachophoresis sample stacking coupling with capillary electrophoresis-amperometric detection for analysis of doping substances.

    Science.gov (United States)

    Zheng, Lihui; Zhang, Lan; Tong, Ping; Zheng, Xinyu; Chi, Yuwu; Chen, Guonan

    2010-06-15

    A simple and effective method of capillary electrophoresis-amperometric detection (CE-AD) coupled with transient isotachophoresis (tITP) was developed for the trace determination of doping substances. Compared with the conventional capillary electrophoresis method, the maximum enhancement factor in terms of peak heights was up to 5500-fold when the tITP technique was adopted. Under the optimum conditions, the detection limit (S/N=3) for methylephedrine (MDP), celiprolol (CEL), sotalol (SOT) and indapamide (IDP) were 4.2 x 10(-14), 6.3 x 10(-13), 5.8 x 10(-14) and 9.5 x 10(-13)molL(-1), respectively. The RSDs of four analytes were 1.0-2.3% for migration time and 2.6-3.8% for peak current, respectively. The proposed method was successfully applied to determine the contents of SOT and IDP in real urine sample, and the excretion curve of IDP within 48h was also investigated. The recoveries of the four doping in urine ranged from 90.0 to 102%.

  18. 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.

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

    Science.gov (United States)

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

    2013-01-01

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

  20. 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.

  1. 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.

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

    Science.gov (United States)

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

    2017-02-01

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

  3. How many taxa can be recognized within the complex Tillandsia capillaris (Bromeliaceae, Tillandsioideae? Analysis of the available classifications using a multivariate approach

    Directory of Open Access Journals (Sweden)

    Lucía Castello

    2013-05-01

    Full Text Available Tillandsia capillaris Ruiz & Pav., which belongs to the subgenus Diaphoranthema is distributed in Ecuador, Peru, Bolivia, northern and central Argentina, and Chile, and includes forms that are difficult to circumscribe, thus considered to form a complex. The entities of this complex are predominantly small-sized epiphytes, adapted to xeric environments. The most widely used classification defines 5 forms for this complex based on few morphological reproductive traits: T. capillaris Ruiz & Pav. f. capillaris, T. capillaris f. incana (Mez L.B. Sm., T. capillaris f. cordobensis (Hieron. L.B. Sm., T. capillaris f. hieronymi (Mez L.B. Sm. and T. capillaris f. virescens (Ruiz & Pav. L.B. Sm. In this study, 35 floral and vegetative characters were analyzed with a multivariate approach in order to assess and discuss different proposals for classification of the T. capillaris complex, which presents morphotypes that co-occur in central and northern Argentina. To accomplish this, data of quantitative and categorical morphological characters of flowers and leaves were collected from herbarium specimens and field collections and were analyzed with statistical multivariate techniques. The results suggest that the last classification for the complex seems more comprehensive and three taxa were delimited: T. capillaris (=T. capillaris f. incana-hieronymi, T. virescens s. str. (=T. capillaris f. cordobensis and T. virescens s. l. (=T. capillaris f. virescens. While T. capillaris and T. virescens s. str. co-occur, T. virescens s. l. is restricted to altitudes above 2000 m in Argentina. Characters previously used for taxa delimitation showed continuous variation and therefore were not useful. New diagnostic characters are proposed and a key is provided for delimiting these three taxa within the complex.

  4. Understanding local forces in electrophoretic ink systems: utilizing optical tweezers to explore electrophoretic display devices

    Science.gov (United States)

    Wei, David L.; Dickinson, Mark R.; Smith, N.; Gleeson, Helen F.

    2016-09-01

    Optical tweezers can be used as a valuable tool to characterize electrophoretic display (EPD) systems. EPDs are ubiquitous with e-readers and are becoming a commonplace technology where reflective, low-power displays are required; yet the physics of some features crucial to their operation remains poorly defined. We utilize optical tweezers as a tool to understand the motion of charged ink particles within the devices and show that the response of optically trapped electrophoretic particles can be used to characterize electric fields within these devices. This technique for mapping the force can be compared to simulations of the electric field in our devices, thus demonstrating that the electric field itself is the sole governor of the particle motion in an individual-particle regime. By studying the individual-particle response to the electric field, we can then begin to characterize particle motion in `real' systems with many particles. Combining optical tweezing with particle tracking techniques, we can investigate deviations in many particle systems from the single-particle case.

  5. Capillary electromigration techniques as tools for assessing the status of vitamins A, C and E in patients with cystic fibrosis.

    Science.gov (United States)

    Olędzka, Ilona; Kaźmierska, Katarzyna; Plenis, Alina; Kamińska, Barbara; Bączek, Tomasz

    2015-01-01

    The purpose of this work is the evaluation of the nutritional status of patients with cystic fibrosis (CF), based on the level of vitamin C in urine and vitamins A and E in serum, using the fast, selective and fully automated micellar electrokinetic capillary chromatographic (MEKC) and microemulsion electrokinetic capillary chromatographic (MEEKC) methods. The optimization of parameters affecting the electrophoretic separation provided adequate separation of the analytes of interest in the short time of 8 min (MEKC) and 20 min (MEEKC). The developed methods were practical applications to evaluate the levels of vitamins A, C and E in real samples from 28 children suffering from cystic fibrosis and from 10 healthy volunteers. Based on the mean concentration values obtained in the two groups, it can be seen that the levels of each vitamin were lower in patients with CF than in healthy volunteers. In the case of vitamin E, these differences in both groups were statistically significant, while the disproportion of concentrations of vitamins A and C in both the studied groups were not so relevant. On the other hand, a principal component analysis (PCA) confirmed that in some patients with CF the concentration of vitamin A was significantly lower than in the control group. Thus, the future evaluation of the status of fat-soluble vitamins in the longer term for the evaluation of the nutritional status of patients with CF should be continued. The presented CE methods can become useful tools for the evaluation of the nutritional status of patients with CF.

  6. Dichotomous electrophoretic taxonomic key for identification of sibling species A, B, and C of the Anopheles quadrimaculatus complex (Diptera: Culicidae).

    Science.gov (United States)

    Narang, S K; Kaiser, P E; Seawright, J A

    1989-03-01

    Samples of 17 populations of Anopheles quadrimaculatus Say from Florida, Alabama, Arkansas, Louisiana, Mississippi, Tennessee, New York, and New Jersey were analyzed for genetic variability at 33 enzyme loci. Statistical analysis of electromorph frequency distributions indicated that sympatric sibling (morphologically indistinguishable) species occurred in about 59% of the populations tested. The association of polytene chromosome and electrophoretic patterns of individual field-collected females confirmed species-specific diagnostic allozymes, which were useful in identifying sibling species A, B, and C and in estimating the proportions of each species at the 17 collection sites. A dichotomous electrophoretic key is presented for the identification of sibling species of the An. quadrimaculatus complex. The electrophoretic method is better than the ovarian polytene chromosome method, because mosquitoes of both sexes and females irrespective of their gonotrophic condition can be identified.

  7. Application of Capillary Electrophoresis in Trace Evidence Analysis%毛细管电泳技术在微量物证检验中的应用

    Institute of Scientific and Technical Information of China (English)

    胡灿; 梅宏成; 郭洪玲; 朱军; 权养科

    2016-01-01

    Capillary electrophoresis (CE) is an electrokinetic separation method performed in capillaries of submillimeter diameter. It is applicable for determining varieties of chemical substances including inorganic ions, small organic molecules, chiral compounds, macromolecules, and intact viruses or cells. In forensic sciences, the characterization and quantitation are of great importance for chemical substances from complex mixtures at trace levels. Separation prior to identification is hence necessary. CE is attractive for forensic applications because of its exceptional separating efficiency, rapid operating speed, economy in reagents and consumables, plus the minimally required amounts of sample. Till present, it has been applied to a wide range of analytes of forensic interests such as DNA, illicit drugs, toxic samples, explosives’ residues, and pen inks. Numerous articles about CE applications involving the analytical problems of potential interest for the forensic researchers and scientists have been published in most premiere journals of chemistry, biochemistry, pharmacology, toxicology, laboratory medicine, human genetics, inter alia. The purpose of this article is to provide an overview of CE application for trace evidence analysis in the following aspects: (i) explosive residue, (ii) gunshot residue, (iii) pen inks, (iv) fiber dyes. The separation principle and six modes of capillary electrophoresis (CZE, MEKC, CGE, CIEF, CITP, CEC) have been summarized, together with the discussion of the advantages and existing problems for the analysis of trace evidence. The main features of CE lie on its applicable versatilities through the same instrument and, in most cases, even the same one capillary, with only the running buffer being changed. Nevertheless, the single use of CE limits its forensic application due to the low sensitivity of UV detection. Promisingly, the coalescence of CE with mass spectrometry (MS) has in recent years significantly improved the

  8. Critical aspects of analysis of Micrococcus luteus, Neisseria cinerea, and Pseudomonas fluorescens by means of capillary electrophoresis.

    Science.gov (United States)

    Hoerr, Verena; Stich, August; Holzgrabe, Ulrike

    2004-10-01

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

  9. 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-re...

  10. Determination of pKa values of tenoxicam from 1H NMR chemical shifts and of oxicams from electrophoretic mobilities (CZE) with the aid of programs SQUAD and HYPNMR.

    Science.gov (United States)

    Rodríguez-Barrientos, Damaris; Rojas-Hernández, Alberto; Gutiérrez, Atilano; Moya-Hernández, Rosario; Gómez-Balderas, Rodolfo; Ramírez-Silva, María Teresa

    2009-12-15

    In this work it is explained, by the first time, the application of programs SQUAD and HYPNMR to refine equilibrium constant values through the fit of electrophoretic mobilities determined by capillary zone electrophoresis experiments, due to the mathematical isomorphism of UV-vis absorptivity coefficients, NMR chemical shifts and electrophoretic mobilities as a function of pH. Then, the pK(a) values of tenoxicam in H(2)O/DMSO 1:4 (v/v) have been obtained from (1)H NMR chemical shifts, as well as of oxicams in aqueous solution from electrophoretic mobilities determined by CZE, at 25 degrees C. These values are in very good agreement with those reported by spectrophotometric and potentiometric measurements.

  11. 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.

  12. 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.

  13. Effect of size, quaternary structure and translational error on the static and dynamic heterogeneity of beta-galactosidase and measurement of electrophoretic dynamic heterogeneity.

    Science.gov (United States)

    Craig, Douglas B; Haslam, Allison M; Silverstein, Harlyn J; Chikamatsu, Miki; Shadabi, Elnaz; Nichols, Ellert R

    2010-08-01

    Single enzyme molecule assays were performed using capillary electrophoresis-based protocols on beta-galactosidase from Lactobacillus delbrueckii, Lactobacillus reuteri, Lactobacillus helveticus and Bacillus circulans. The enzyme was found to show static heterogeneity with respect to catalytic rate and the variance in rate increased with protein size. This is consistent with the proposal that random errors in translation may be an important underlying component of enzyme heterogeneity. Additionally these enzymes were found to show static heterogeneity with respect to electrophoretic mobility. Comparison of wild-type and rpsL E. coli beta-galactosidase expressed in the presence and absence of streptomycin suggested that increases in error do not result in detectable increases in the dynamic heterogeneity of activity with increasing temperature. Finally, a method was developed to measure the dynamic heterogeneity in electrophoretic mobility.

  14. 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.

  15. Affinity capillary electrophoresis: the theory of electromigration.

    Science.gov (United States)

    Dubský, Pavel; Dvořák, Martin; Ansorge, Martin

    2016-12-01

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

  16. 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.

  17. 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

  18. 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.

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

    Science.gov (United States)

    Wei, Chong; Hou, Zhanwu; Wang, Zilong; Yuan, Jiaqiang; Yu, Jiang; Zhao, Yongxi; Tang, Yuhai; Gao, Meili

    2014-01-01

    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. PMID:25197612

  1. 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.

  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. Powerful preconcentration method for capillary electrophoresis and its application to analysis of ultratrace amounts of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Takagai, Yoshitaka; Akiyama, Ryoutaro; Igarashi, Shukuro

    2006-07-01

    For environmental analyses, a high-performance and powerful preconcentration system exceeding 1 x 10(7)-fold was developed that was composed of a blue cotton method (solid extraction method)/homogeneous liquid-liquid extraction method/on-line concentration method for capillary electrophoresis (CE). This system was named the "triplex concentration system" and it was achieved by finding a new phase-separation phenomenon (homogeneous liquid-liquid extraction) from a water-miscible organic solvent. Parts per trillion levels of polycyclic aromatic hydrocarbons (PAHs) were used as model analytical targets in this study. With the proposed method, 20-L levels of environmental water could be preconcentrated up to 1 x 10(7)-fold within a maximum of 1 h. The parts per trillion levels of PAHs were easily determined even using UV/CE, which has a serious sensitivity problem, and the detection limit of benzo[a]pyrene was 3.60 ppt. This system was also used as a practical monitoring method for the Miyata River (in Japan).

  4. 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.

  5. 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.

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

    Science.gov (United States)

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

    2013-01-25

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

  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. 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

  9. 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.

  10. 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.

  11. 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.

  12. Passive Fluidic Chip Composed of Integrated Vertical Capillary Tubes Developed for On-Site SPR Immunoassay Analysis Targeting Real Samples

    Directory of Open Access Journals (Sweden)

    Tsuneyuki Haga

    2012-05-01

    Full Text Available We have successfully developed a surface plasmon resonance (SPR measurement system for the on-site immunoassay of real samples. The system is composed of a portable SPR instrument (290 mm(W x 160 mm(D x 120 mm(H and a microfluidic immunoassay chip (16 mm(W x 16 mm(D x 4 mm(H that needs no external pump system. An integrated vertical capillary tube functions as a large volume (150 μL passive pump and a waste reservoir that has sufficient capacity for several refill operations. An immunoassay was carried out that employed the direct injection of a buffer and a test sample in sequence into a microfluidic chip that included 9 antibody bands and 10 reference reagent bands immobilized in the flow channel. By subtracting a reliable averaged reference sensorgram from the antibody, we effectively reduced the influence of the non-specific binding, and then our chip successfully detected the specific binding of spiked IgG in non-homogeneous milk. IgG is a model antigen that is certain not to be present in non-homogeneous milk, and non-homogeneous milk is a model of real sample that includes many interfering foreign substances that induce non-specific binding. The direct injection of a real sample with no pretreatment enabled us to complete the entire immunoassay in several minutes. This ease of operation and short measuring time are acceptable for on-site agricultural, environmentaland medical testing.

  13. Optimization of a microfluidic electrophoretic immunoassay using a Peltier cooler.

    Science.gov (United States)

    Mukhitov, Nikita; Yi, Lian; Schrell, Adrian M; Roper, Michael G

    2014-11-07

    Successful analysis of electrophoretic affinity assays depends strongly on the preservation of the affinity complex during separations. Elevated separation temperatures due to Joule heating promotes complex dissociation leading to a reduction in sensitivity. Affinity assays performed in glass microfluidic devices may be especially prone to this problem due to poor heat dissipation due to the low thermal conductivity of glass and the large amount of bulk material surrounding separation channels. To address this limitation, a method to cool a glass microfluidic chip for performing an affinity assay for insulin was achieved by a Peltier cooler localized over the separation channel. The Peltier cooler allowed for rapid stabilization of temperatures, with 21°C the lowest temperature that was possible to use without producing detrimental thermal gradients throughout the device. The introduction of cooling improved the preservation of the affinity complex, with even passive cooling of the separation channel improving the amount of complex observed by 2-fold. Additionally, the capability to thermostabilize the separation channel allowed for utilization of higher separation voltages than what was possible without temperature control. Kinetic CE analysis was utilized as a diagnostic of the affinity assay and indicated that optimal conditions were at the highest separation voltage, 6 kV, and the lowest separation temperature, 21°C, leading to 3.4% dissociation of the complex peak during the separation. These optimum conditions were used to generate a calibration curve and produced 1 nM limits of detection, representing a 10-fold improvement over non-thermostated conditions. This methodology of cooling glass microfluidic devices for performing robust and high sensitivity affinity assays on microfluidic systems should be amenable in a number of applications.

  14. 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.

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

    Science.gov (United States)

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

    2009-02-01

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

  16. 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.

  17. Chemometrics optimization of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection.

    Science.gov (United States)

    Zhu, Derong; Li, Xia; Sun, Jinying; You, Tianyan

    2012-01-15

    This work expanded the knowledge of the use of chemometric experimental design in optimizing of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection. Specially, central composite design was employed for optimizing the three critical electrophoretic variables (Tris-H(3)PO(4) buffer concentration, buffer pH value and separation voltage) using the chromatography resolution statistic function (CRS function) as the response variable. The optimum conditions were established from empirical model: 24.2mM Tris-H(3)PO(4) buffer (pH 2.7) with separation voltage of 15.9 kV. Applying theses conditions, the six antihistamines (carbinoxamine, chlorpheniramine, cyproheptadine, doxylamine, diphenhydramine and ephedrine) could be simultaneous separated in less than 22 min. Our results indicate that the chemometrics optimization method can greatly simplify the optimization procedure for multi-component analysis. The proposed method was also validated for linearity, repeatability and sensitivity, and was successfully applied to determine these antihistamine drugs in urine.

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. Predicting Electrophoretic Mobility of Protein-Ligand Complexes for Ligands from DNA-Encoded Libraries of Small Molecules.

    Science.gov (United States)

    Bao, Jiayin; Krylova, Svetlana M; Cherney, Leonid T; Hale, Robert L; Belyanskaya, Svetlana L; Chiu, Cynthia H; Shaginian, Alex; Arico-Muendel, Christopher C; Krylov, Sergey N

    2016-05-17

    Selection of target-binding ligands from DNA-encoded libraries of small molecules (DELSMs) is a rapidly developing approach in drug-lead discovery. Methods of kinetic capillary electrophoresis (KCE) may facilitate highly efficient homogeneous selection of ligands from DELSMs. However, KCE methods require accurate prediction of electrophoretic mobilities of protein-ligand complexes. Such prediction, in turn, requires a theory that would be applicable to DNA tags of different structures used in different DELSMs. Here we present such a theory. It utilizes a model of a globular protein connected, through a single point (small molecule), to a linear DNA tag containing a combination of alternating double-stranded and single-stranded DNA (dsDNA and ssDNA) regions of varying lengths. The theory links the unknown electrophoretic mobility of protein-DNA complex with experimentally determined electrophoretic mobilities of the protein and DNA. Mobility prediction was initially tested by using a protein interacting with 18 ligands of various combinations of dsDNA and ssDNA regions, which mimicked different DELSMs. For all studied ligands, deviation of the predicted mobility from the experimentally determined value was within 11%. Finally, the prediction was tested for two proteins and two ligands with a DNA tag identical to those of DELSM manufactured by GlaxoSmithKline. Deviation between the predicted and experimentally determined mobilities did not exceed 5%. These results confirm the accuracy and robustness of our model, which makes KCE methods one step closer to their practical use in selection of drug leads, and diagnostic probes from DELSMs.

  3. Electrophoretic deposition and constrained sintering of strontium titanate thick films

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Luís; Vilarinho, Paula M., E-mail: paula.vilarinho@ua.pt; Senos, Ana M.R.

    2015-01-15

    Thick films of functional oxides are currently substituting counterparts bulk ceramics, as in the case of low loss dielectrics. For SrTiO{sub 3} (ST) based compositions it is demonstrated that electrophoretic deposition (EPD), using acetone as a suspension media with iodine addition, is a suitable technology to fabricate 12 μm thick films. The microstructural analysis of the films sintered at 1500 °C shows that highly densified microstructures can be obtained and, by slightly varying the Sr/Ti stoichiometry in the powder composition, increased densification and grain size and enlargement of the distribution with decreasing Sr/Ti ratio can be observed. In spite of the high densification of the films, it is also demonstrated that due to the constraint imposed by the substrate a smaller grain size is observed in thick films as compared to equivalent bulk ceramics. In addition, a preferential vertical pore orientation is observed in ST thick films. These results may have broad implications if one considers that the dielectric losses and dielectric tunability is affected by pore orientation, since it affects the electric field distribution. - Highlights: • Nonstoichiometry effect on microstructure of constrained sintered thick films and bulk is similar. • Increased densification and grain size and enlargement of distribution with decreasing Sr/Ti ratio. • Independent of Sr/Ti ratio smaller grain size for thick films compared to ceramics. • Preferential vertical pore orientation for constrained sintering of thick films. • Anisotropic porosity as tailoring factor to engineer permittivity and tunability.

  4. Electrosteric stabilization of colloidal TiO2 nanoparticles with DNA and polyethylene glycol for selective enhancement of UV detection sensitivity in capillary electrophoresis analysis.

    Science.gov (United States)

    Alsudir, Samar; Lai, Edward P C

    2017-03-01

    A new approach to selectively enhance the ultraviolet (UV) detection sensitivity of titania (TiO2), albeit in the presence of silica (SiO2), alumina (Al2O3), and zinc oxide (ZnO), nanoparticles in capillary electrophoresis (CE) analysis was developed. Interactions of Triton X-100 (TX-100), polyethylene glycol (PEG), and deoxyribonucleic acid (DNA) with TiO2 nanoparticles produced larger CE-UV peaks at various enhancement factors. Single-stranded DNA (ssDNA) was a more effective adsorbate than double-stranded DNA (dsDNA) due to its flexible molecular structure that participated in a stronger interaction with TiO2 nanoparticles via its sugar-phosphate backbone. Disaggregation of TiO2 nanoparticles upon DNA binding due to electrosteric stabilization was validated using dynamic light scattering. PEG coating of TiO2-DNA nanoparticles further enhanced the UV detection sensitivity in CE analysis by providing extra electrosteric stabilization. This analytical technique, which involves binding of TiO2 nanoparticles with DNA followed by coating with PEG, has allowed us to achieve progressively an enhancement factor up to 13.0 ± 3.0 - fold in analytical sensitivity for the accurate determination of disaggregated TiO2 nanoparticles. Graphical Abstract Selective enhancement of UV detection sensitivity for TiO2 nanoparticles via electrosteric stabilization using ssDNA and PEG.

  5. 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

  6. 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].

  7. 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.

  8. 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

  9. Sweeping of alprenolol enantiomers with an organic solvent and sulfated β-cyclodextrin in capillary electrophoresis.

    Science.gov (United States)

    Rabanes, Heide R; Quirino, Joselito P

    2013-05-01

    Sweeping, an on-line sample concentration technique in CE, is the picking and accumulation of analytes by the pseudostationary phase or complexing additive. In the presence of an electric field, the analytes concentrated at the additive front that initially penetrated the sample zone. Here, we describe the sweeping of cationic alprenolol enantiomers using sulfated β-CD and organic solvent. The separation solution contained the anionic additive while ACN was in the sample solution. With fused silica capillaries, positive polarity, and solutions buffered at pH 3, the direction of the enantiomers' effective electrophoretic mobility was the same as the electrophoretic mobility (or electrophoretic mobility without additive). When the amount of ACN in the sample was increased (i.e. 60%), the interaction between the analytes and additive became negligible. This caused the sweeping boundary to shift from the electrophoretically moving β-CD front to the zone between the sample and separation solution. The equation that described the narrowing of injected sample zone was derived. The performance of sweeping with 60% ACN in the sample was then studied under different operating conditions (e.g. type of injection, injection time, and CD concentration). The low interaction between enantiomers and additive gave only moderate increases in sensitivity (approximately tenfold), but was improved when field enhancement was used during electrokinetic injection. With a conductivity difference (separation/sample solution) of 70 and a short injection time of 30 s at 20 kV, peak improvements of >100-fold was easily achieved.

  10. Biologically driven neural platform invoking parallel electrophoretic separation and urinary metabolite screening.

    Science.gov (United States)

    Page, Tessa; Nguyen, Huong Thi Huynh; Hilts, Lindsey; Ramos, Lorena; Hanrahan, Grady

    2012-06-01

    This work reveals a computational framework for parallel electrophoretic separation of complex biological macromolecules and model urinary metabolites. More specifically, the implementation of a particle swarm optimization (PSO) algorithm on a neural network platform for multiparameter optimization of multiplexed 24-capillary electrophoresis technology with UV detection is highlighted. Two experimental systems were examined: (1) separation of purified rabbit metallothioneins and (2) separation of model toluene urinary metabolites and selected organic acids. Results proved superior to the use of neural networks employing standard back propagation when examining training error, fitting response, and predictive abilities. Simulation runs were obtained as a result of metaheuristic examination of the global search space with experimental responses in good agreement with predicted values. Full separation of selected analytes was realized after employing optimal model conditions. This framework provides guidance for the application of metaheuristic computational tools to aid in future studies involving parallel chemical separation and screening. Adaptable pseudo-code is provided to enable users of varied software packages and modeling framework to implement the PSO algorithm for their desired use.

  11. 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).

  12. Electrophoretic separation of A gamma and G gamma human globin chains in Nonidet P-40.

    Science.gov (United States)

    Guerrasio, A; Saglio, G; Mazza, U; Pich, P; Camaschella, C; Ricco, G; Gianazza, E; Righetti, P G

    1979-11-15

    Electrophoresis in cellulose acetate in the presence of 3% Nonidet P-40 can resolve two neutral genetic variants, A gamma and G gamma human fetal globin chains. The ratio of these two chains, determined by densitometry of the electrophoretic strips, is in excellent agreement with the Gly-Ala ratio obtained by chemical analysis of the cyanogen bromide fragment gamma CB3. It is suggested that the detergent binds preferentially to the hydrophobic amino acid segment 133-141 in the A gamma chain, thus masking either a Lys or an Arg residue at the two extremes.

  13. 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 ...

  14. Phylogenetic relationships among wine yeast strains based on electrophoretic whole-cell protein patterns.

    Science.gov (United States)

    Guillamón, J M; Querol, A; Jiménez, M; Huerta, T

    1993-04-01

    In the present work, a phylogenetic study based on protein electrophoretic profiles of Saccharomyces strains isolated from different Spanish wine regions has been carried out. Qualitative differences between the protein electrophoregrams were found at inter- and intraspecific level, but not between electrophoregrams of strains isolated at the same ecosystem. The numerical analysis of these results allowed us to conclude that intraspecific relationships are determined by ecological factors, as well as human influences (dispersion and artificial selection). A correlation between ecological and/or geographical origin and the relationships among strains was observed.

  15. Variation in the electrophoretic karyotype of Brazilian strains of Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Valadares-Inglis Maria Cléria

    1998-01-01

    Full Text Available Pulsed-field gel electrophoresis (PFGE was used to separate chromosome-sized DNA molecules of four strains of Metarhizium anisopliae from Brazil. Metarhizium anisopliae isolates from Japan have been reported as possessing seven chromosomes. Variation was observed among the Brazilian strains and the chromosomal DNA was resolved into eight bands for strain CG46. Densitometric analysis of PFGE gels suggested that the other three Brazilian strains also possess eight chromosomes, with two chromosomes migrating as doublets under the electrophoretic conditions used. The genome size was estimated as varying between 23.39 to 31.88 Mb, not including possible doublet chromosomes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Proefrock, Daniel; Prange, Andreas E-mail: andreas.prange@gkss.de; Schaumloeffel, Dirk; Ruck, Wolfgang

    2003-08-15

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

  17. Comparing nanostructured hydroxyapatite coating on AZ91 alloy samples via sol-gel and electrophoretic deposition for biomedical applications.

    Science.gov (United States)

    Rojaee, Ramin; Fathi, Mohammadhossein; Raeissi, Keyvan

    2014-12-01

    Magnesium is one of the most critical elements in hard tissues regeneration and therefore causes speeding up the restoration of harmed bones, while high deterioration rate of magnesium in body fluid restricts it to be used as biodegradable implants. Alloying magnesium with some relatively nobler metals such as aluminium, zinc, rare earth elements, magnesium-bioceramics composites, and surface modification techniques are some of the routes to control magnesium corrosion rate. In this study AZ91 magnesium alloy had been coated by nanostructured hydroxyapatite via sol-gel dip coating and electrophoretical methods to survey the final barricade properties of the obtained coatings. In order to perform electrophoretic coating, powders were prepared by sol-gel method, and then the powders deposited on substrates utilizing direct current electricity. Zeta potentials of the electrophoresis suspensions were measured to determine a best mode for good quality coatings. Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) were used to confirm nanoscale dimension, and the uniformity of the nanostructured hydroxyapatite coating, respectively. Fourier Transform-Infrared and X-ray diffraction analysis were utilized for functional group and phase structure evaluation of the prepared coatings, correspondingly. Electrochemical corrosion tests were performed in SBF at 37±1 (°)C which revealed considerable increase in corrosion protection resistivity and corrosion current density for electrophoretic coated specimens versus sol-gel coated specimens. Results showed that both sol-gel and electrophoretical techniques seem to be suitable to coat magnesium alloys for biomedical applications but electrophoretic coating technique is a better choice due to the more homogeneity and more crystalline structure of the coating.

  18. 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.

  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.

  20. 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.

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

    Science.gov (United States)

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

    2016-10-07

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

  2. 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.)

  3. Estimation of apparent binding constant of complexes of selected acyclic nucleoside phosphonates with β-cyclodextrin by affinity capillary electrophoresis.

    Science.gov (United States)

    Šolínová, Veronika; Mikysková, Hana; Kaiser, Martin Maxmilián; Janeba, Zlatko; Holý, Antonín; Kašička, Václav

    2016-01-01

    Affinity capillary electrophoresis (ACE) has been applied to estimation of apparent binding constant of complexes of (R,S)-enantiomers of selected acyclic nucleoside phosphonates (ANPs) with chiral selector β-cyclodextrin (βCD) in aqueous alkaline medium. The noncovalent interactions of five pairs of (R,S)-enantiomers of ANPs-based antiviral drugs and their derivatives with βCD were investigated in the background electrolyte (BGE) composed of 35 or 50 mM sodium tetraborate, pH 10.0, and containing variable concentration (0-25 mM) of βCD. The apparent binding constants of the complexes of (R,S)-enantiomers of ANPs with βCD were estimated from the dependence of effective electrophoretic mobilities of (R,S)-enantiomers of ANPs (measured simultaneously by ACE at constant reference temperature 25°C inside the capillary) on the concentration of βCD in the BGE using different nonlinear and linear calculation methodologies. Nonlinear regression analysis provided more precise and accurate values of the binding constants and a higher correlation coefficient as compared to the regression analysis of the three linearized plots of the effective mobility dependence on βCD concentration in the BGE. The complexes of (R,S)-enantiomers of ANPs with βCD have been found to be relatively weak - their apparent binding constants determined by the nonlinear regression analysis were in the range 13.3-46.4 L/mol whereas the values from the linearized plots spanned the interval 12.3-55.2 L/mol.

  4. Reliable electrophoretic mobilities free from Joule heating effects using CE.

    Science.gov (United States)

    Evenhuis, Christopher J; Hruska, Vlastimil; Guijt, Rosanne M; Macka, Miroslav; Gas, Bohuslav; Marriott, Philip J; Haddad, Paul R

    2007-10-01

    Ionic electrophoretic mobilities determined by means of CE experiments are sometimes different when compared to generally accepted values based on limiting ionic conductance measurements. While the effect of ionic strength on electrophoretic mobility has been long understood, the increase in the mobility that results from Joule heating (the resistive heating that occurs when a current passes through an electrolyte) has been largely overlooked. In this work, a simple method for obtaining reliable and reproducible values of electrophoretic mobility is described. The electrophoretic mobility is measured over a range of driving powers and the extrapolation to zero power dissipation is employed to eliminate the effect of Joule heating. These extrapolated values of electrophoretic mobility can then be used to calculate limiting ionic mobilities by making a correction for ionic strength; this somewhat complicated calculation is conveniently performed by using the freeware program PeakMaster 5. These straightforward procedures improve the agreement between experimentally determined and literature values of limiting ionic mobility by at least one order of magnitude. Using Tris-chromate BGE with a value of conductivity 0.34 S/m and ionic strength 59 mM at a modest dissipated power per unit length of 2.0 W/m, values of mobility for inorganic anions were increased by an average of 12.6% relative to their values free from the effects of Joule heating. These increases were accompanied by a reduction in mobilities due to the ionic strength effect, which was 11% for univalent and 28% for divalent inorganic ions compared to their limiting ionic mobilities. Additionally, it was possible to determine the limiting ionic mobility for a number of aromatic anions by using PeakMaster 5 to perform an ionic strength correction. A major significance of this work is in being able to use CE to obtain reliable and accurate values of electrophoretic mobilities with all its benefits, including

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

    Science.gov (United States)

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

    2014-10-01

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

  6. 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.

  7. Preparation of Panel and Charged Particles for Electrophoretic Display

    Science.gov (United States)

    Choi, Hyung Suk; Park, Jin Woo; Park, Lee Soon; Lee, Jung Kyung; Han, Yoon Soo; Kwon, Younghwan

    Studies on the formulation of photosensitive paste for transparent soft mold press (TSMP) method have been performed. With the optimum formulation of the photosensitive paste the box-type barrier rib with good flexibility and high solvent resistance was fabricated, suitable for the panel material of the electrophoretic display. Cationically-charged white particles were prepared by using TiO2 nanoparticles, silane coupling agent with amino groups, dispersant and acetic acid. The cationically charged TiO2 particles exhibited 74.09 mV of zeta potential and 3.11 × 10-5 cm2/Vs of mobility. Electrophoretic display fabricated with the charged TiO2 particles exhibited 10 V of low driving voltage and maximum contrast ratio (5.3/1) at 30 V.

  8. Combination of capillary micellar liquid chromatography with on-chip microfluidic chemiluminescence detection for direct analysis of buspirone in human plasma.

    Science.gov (United States)

    Al Lawati, Haider A J; Kadavilpparampu, Afsal Mohammed; Suliman, FakhrEldin O

    2014-09-01

    Microfluidic based chemiluminescence (CL) detector having novel channel design for enhanced mixing has been developed and investigated in terms of its applicability with micellar mode of liquid chromatography (MLC). The newly developed detector was found to be highly sensitive and an alternative detection technique to combine with capillary MLC. This combination was successfully employed for direct detection of a model analyte using Ru(III)-peroxydisulphate CL system. The selected analyte, buspirone hydrochloride (BUS), was detected selectively at therapeutic concentration levels in human plasma without any sample pretreatment. By incorporating eight flow split units within the spiral channel of microfluidic chip, an enhancement of 140% in CL emission was observed. We also evaluated the effect of non- ionic surfactant, Brij-35, which used as mobile phase modifier in MLC, on CL emission. The CL signal was improved by 52% compared to aqueous-organic mobile phase combinations. Various parameters influencing the micellar chromatographic performance and the CL emission were optimized. This allowed highly sensitive analysis of BUS with limit of detection (LOD) of 0.27 ng mL(-1) (3σ/s) and limit of quantification (LOQ) of 0.89 ng mL(-1) (10σ/s). The analyte recovery from human plasma at three different concentration level ranges from 88% to 96% (RSD 1.9-5.3%). The direct analysis of BUS in human plasma was achieved within 6 min. Therefore, combining microfluidic CL detection with micellar mode of separation is an efficient, cost-effective and highly sensitive technique that can utilize MLC in its full capacity for various bioanalytical procedures.

  9. 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.

  10. Computer-assisted identification of multitrace electrophoretic patterns in differential display experiments.

    Science.gov (United States)

    Vähämaa, Heidi; Ojala, Pekka; Pahikkala, Tapio; Nevalainen, Olli S; Lahesmaa, Riitta; Aittokallio, Tero

    2007-03-01

    Modern multicapillary devices allow researchers to address increasingly complex biological questions involving comparisons of gene expression patterns across electrophoretic samples under various experimental conditions. As labor-intensive visual evaluation of the electrophoretic results is often the bottleneck of large-scale differential display (DD) studies, one way to further streamline this process is to focus only on a highly compressed list of the most potential patterns that are likely to provide reliable findings. To enable the identification of such candidate patterns, we present a computer-assisted method for objective ranking of multitrace peak patterns in DD experiments. The fundamental component of the multitrace pattern ranking method (MRANK) is the multiple alignment algorithm that allows for discovery of patterns involving sets of peak complexes from various electrophoretic samples. A score value is attached to each detected pattern which characterizes how accurately the pattern resembles the desired pattern query, freely defined by the researcher. The ranked pattern list produced by MRANK is validated against visual evaluation in terms of detecting and ranking a group of relevant patterns in a DD analysis of T-helper cell differentiation. We demonstrate high enrichment of the desired patterns on top of the score-ranked list (e.g., 90% of the visually selected patterns are discovered by looking through the first 3% of patterns in the ranked list of all patterns). The results suggest that a substantial amount of manual labor can be saved without compromising the accuracy of the findings by prioritizing the patterns according to MRANK output in the visual confirmation phase.

  11. Simulations of Electrophoretic RNA Transport Through Transmembrane Carbon Nanotubes

    OpenAIRE

    Zimmerli, Urs; Koumoutsakos, Petros

    2008-01-01

    The study of interactions between carbon nanotubes and cellular components, such as membranes and biomolecules, is fundamental for the rational design of nanodevices interfacing with biological systems. In this work, we use molecular dynamics simulations to study the electrophoretic transport of RNA through carbon nanotubes embedded in membranes. Decorated and naked carbon nanotubes are inserted into a dodecane membrane and a dimyristoylphosphatidylcholine lipid bilayer, and the system is sub...

  12. A novel method for the preparation of electrophoretic display microcapsules

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao-Meng; He, Jing; Liu, Sheng-Yun [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Chen, Jian-Feng [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Le, Yuan, E-mail: leyuan@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2014-07-01

    Highlights: • The electrophoretic display microcapsules were prepared by coaxial jet method aided by gas spray. • The positions of inner tube, liquid and gas flow rate of the process were investigated. • The size and shell thickness of the prepared microcapsules were controllable. • The prepared microcapsules had high coating ratio and exhibit reversible response to DC field. - Abstract: The narrow distributed electrophoretic display microcapsules containing electrophoretic ink were prepared using coaxial jet method aided by gas spray. Experimental results showed the size and shell thickness of the microcapsules could be controlled by adjusting flow rates of core and shell fluids as well as gas. The as-prepared white and red microcapsules, with average size of 100 and 200 μm respectively, had high coating ratio (above 90%) and exhibited reversible response to DC electric field. Compared with the approach of other microencapsulation methods, the new technique not only has a simple procedure but also provides a more effective way of size control. This novel method is expected to prepare microcapsules with potential application in the fields of electronic paper and other material science.

  13. 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.

  14. Analysis of yohimbine alkaloid from Pausinystalia yohimbe by non-aqueous capillary electrophoresis and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Chen, Qinhua; Li, Peng; Zhang, Zhuo; Li, Kaijun; Liu, Jia; Li, Qiang

    2008-07-01

    In the present work, the qualitative and quantitative analysis of Pausinystalia yohimbe-type alkaloids in the barks of Rubiaceae species is presented using different analytical approaches. Extracts of P. yohimbe were first examined by GC-MS and the major alkaloids were identified. The quantitation of yohimbine was then accomplished by non-aqueous CE (NACE) with diode array detection. This approach was selected in order to use a running buffer fully compatible with samples in organic solvent. In particular, a mixture of methanol containing ammonium acetate (20 mM) and glacial acetic acid was used as a BGE. The same analytical sample was subjected to GC-MS and NACE analysis; the different selectivity displayed by these techniques allowed different separation profiles that can be useful in phytochemical characterization of the extracts. The linear calibration ranges were all 10-1000 microg/mL for yohimbine by GC-MS and NACE analysis. The recovery of yohimbine was 91.2-94.0% with RSD 1.4-4.3%. The LOD for yohimbine were 0.6 microg/mL by GC-MS and 1.0 microg/mL by NACE, respectively. The GC-MS and NACE methods were successfully validated and applied to the quantitation of yohimbine.

  15. 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.

  16. 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.

  17. Physical investigation of electrophoretically deposited graphene oxide and reduced graphene oxide thin films

    Science.gov (United States)

    Politano, Grazia Giuseppina; Versace, Carlo; Vena, Carlo; Castriota, Marco; Ciuchi, Federica; Fasanella, Angela; Desiderio, Giovanni; Cazzanelli, Enzo

    2016-11-01

    Graphene oxide and reduced graphene oxide thin films are very promising materials because they can be used in optoelectronic devices and in a growing range of applications such as touch screens and flexible displays. In this work, graphene oxide (GO) and thermally reduced graphene oxide (rGO) thin films, deposited on Ti/glass substrates, have been obtained by electrophoretic deposition. The morphological and the structural properties of the samples have been investigated by micro-Raman technique, X-ray reflectometry, and SEM analysis. In order to study the optical and electrical properties, variable angle spectroscopic ellipsometry and impedance analysis have been performed. The thermal annealing changes strongly the structural, electrical, and optical properties, because during the thermal processes some amount of sp3 bonds originally present in GO were removed. In particular, the annealing enhances the Ohmic behavior of the rGO film increasing its conductivity and the estimated optical density. Moreover, using electrophoretic deposition, we have found a higher value of optical density for GO thin films, not observed in GO films obtained with other deposition methods.

  18. 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.

  19. Quantitative capillary electrophoresis and its application in analysis of alkaloids in tea, coffee, coca cola, and theophylline tablets.

    Science.gov (United States)

    Li, Mengjia; Zhou, Junyi; Gu, Xue; Wang, Yan; Huang, Xiaojing; Yan, Chao

    2009-01-01

    A quantitative CE (qCE) system with high precision has been developed, in which a 4-port nano-valve was isolated from the electric field and served as sample injector. The accurate amount of sample was introduced into the CE system with high reproducibility. Based on this system, consecutive injections and separations were performed without voltage interruption. Reproducibilities in terms of RSD lower than 0.8% for retention time and 1.7% for peak area were achieved. The effectiveness of the system was demonstrated by the quantitative analysis of caffeine, theobromine, and theophylline in real samples, such as tea leaf, roasted coffee, coca cola, and theophylline tablets.

  20. 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.

  1. 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.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    Marina F. M. Tavares

    1997-10-01

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

  4. Determination of partition coefficient and analysis of nitrophenols by three-phase liquid-phase microextraction coupled with capillary electrophoresis.

    Science.gov (United States)

    Sanagi, Mohd Marsin; Miskam, Mazidatulakmam; Wan Ibrahim, Wan Aini; Hermawan, Dadan; Aboul-Enein, Hassan Y

    2010-07-01

    A three-phase hollow fiber liquid-phase microextraction method coupled with CE was developed and used for the determination of partition coefficients and analysis of selected nitrophenols in water samples. The selected nitrophenols were extracted from 14 mL of aqueous solution (donor solution) with the pH adjusted to pH 3 into an organic phase (1-octanol) immobilized in the pores of the hollow fiber and finally backextracted into 40.0 microL of the acceptor phase (NaOH) at pH 12.0 located inside the lumen of the hollow fiber. The extractions were carried out under the following optimum conditions: donor solution, 0.05 M H(3)PO(4), pH 3.0; organic solvent, 1-octanol; acceptor solution, 40 microL of 0.1 M NaOH, pH 12.0; agitation rate, 1050 rpm; extraction time, 15 min. Under optimized conditions, the calibration curves for the analytes were linear in the range of 0.05-0.30 mg/L with r(2)>0.9900 and LODs were in the range of 0.01-0.04 mg/L with RSDs of 1.25-2.32%. Excellent enrichment factors of up to 398-folds were obtained. It was found that the partition coefficient (K(a/d)) values were high for 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol and 2,6-dinitrophenol and that the individual partition coefficients (K(org/d) and K(a/org)) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. The developed method was successfully applied for the analysis of water samples.

  5. Recent developments in capillary and chip electrophoresis of bioparticles: Viruses, organelles, and cells.

    Science.gov (United States)

    Subirats, Xavier; Blaas, Dieter; Kenndler, Ernst

    2011-06-01

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

  6. Using sheath-liquid reagents for capillary electrophoresis-mass spectrometry: application to the analysis of phenolic plant extracts.

    Science.gov (United States)

    Maringer, Leila; Ibáñez, Elena; Buchberger, Wolfgang; Klampfl, Christian W; Causon, Tim J

    2015-01-01

    The combination of CE and MS is now a widely used tool that can provide a combination of high resolution separations with detailed structural information. Recently, we highlighted the benefits of an approach to add further functionality to this well-established hyphenated technique, namely the possibility to perform chemical reactions within the sheath-liquid of the CE-MS interface . Apart from using hydrogen/deuterium exchange for online determination of numbers of exchangeable protons, the addition of DPPH• (2,2-diphenyl-1-picrylhydrazyl) to the sheath-liquid can be used as a fast screening tool for studying antioxidant characteristics of individual components. Such a CE-MS methodology allows rapid and information-rich analysis with minimal reagent and sample consumption to be performed. In the present work, we demonstrate the applicability of this approach for the characterization of phenolic plant extracts from the Labiatae family, namely Rosmarinus officinalis and Melissa officinalis. Using the described approach, a wide range of compounds (15 and 13 phenolic compounds, respectively) could be confidently identified using a combination of high resolution CE-MS separations with implementation of online deuterium exchange and DPPH• reactions. These compounds included polyphenols, phenolic acids, and triterpene acids. In conjunction with online MS/MS experiments, extensive structural information for aglyconic and glycosylated antioxidants present in the extracts could be obtained using simple experimental changes, which can be carried out prior to the purchasing of expensive chemical standards or the time-consuming preparative isolation of individual compounds.

  7. Strategies of fluorescence staining for trace total ribonucleic acid analysis by capillary electrophoresis with argon ion laser-induced fluorescence.

    Science.gov (United States)

    Chung, Yi-An; Chen, Yi-Hsin; Chang, Po-Ling

    2015-08-01

    In this work, five fluorescent dyes (SYTO-9, SYBR Green I, SYBR Green II, SYBR Safe, and SYBR Gold) were used as both on-column and precolumn stains for total RNA analysis by CE-LIF with Ar ion laser excitation. In the on-column RNA stain, the SYTO-9 provided the highest fluorescence intensity and the lowest detectable concentration, as low as 10 pg/μL, while the SYBR Green II and SYBR Gold were adsorbed on the poly(ethylene oxide) thus affected the separation efficiency. As a precolumn stain, SYBR Gold was the most sensitive among the five dyes due to the strong affinity between the dye and RNA molecules. As a result, a single-cell quantity of RNA (10-30 pg per cell) could be detected by CE-LIF with precolumn staining by SYBR Gold. Because of the great savings of fluorescent dye using precolumn stain (one button dye may use for one million stain), this method is the best strategy for RNA staining in terms of cost-effectiveness and sensitivity.

  8. Analysis of amphetamines in urine with liquid-liquid extraction by capillary electrophoresis with simultaneous electrochemical and electrochemiluminescence detection.

    Science.gov (United States)

    Sun, Jinying; Xu, Xiaoyu; Wang, Chunyan; You, Tianyan

    2008-10-01

    Amphetamines including methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine were separated and detected by CE using simultaneous electrochemical (EC) and electrochemiluminescence (ECL) detection (CE-EC/ECL). Factors that influenced the separation and detection performance, such as the detection potential, the pH value and concentration of the running buffer, the separation voltage and the pH of the detection buffer, were investigated. LODs of 3.3x10(-8) mol/L (0.16 fmol), 1.6x10(-7) mol/L (0.78 fmol) and 3.3x10(-8) mol/L (0.16 fmol) were obtained for methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine, respectively. For practical application, a liquid-liquid extraction with ethyl acetate procedure was developed for urine sample pretreatment and extraction efficiencies higher than 90% were obtained. The established simultaneous CE-EC/ECL was successfully applied for urine sample analysis.

  9. Is pulsed electric field still effective for RNA separation in capillary electrophoresis?

    Science.gov (United States)

    Li, Zhenqing; Dou, Xiaoming; Ni, Yi; Chen, Qinmiao; Cheng, Shuyi; Yamaguchi, Yoshinori

    2012-03-16

    Pulsed field capillary electrophoresis (PFCE) is a predominant technique to cope with difficulties in resolving large DNA strands, yet it is still unclear whether pulsed electric field is effective for the separation of higher mass RNA. In this paper we focused on the role of pulsed electric field in large RNA fragments analysis by comparing RNA separation performance in PFCE with that in constant field CE. Separation performance in terms of migration mobility, plate numbers, resolution, and selectivity has been tested for the analysis of RNA from 0.1 to 10.0 kilo nucleotide (knt) under different electrophoretic conditions. Denaturation, important to obtain uniform and identifiable peaks, was accomplished by heating the sample in 4.0M urea prior to analysis and the presence of 4.0M urea in the electrophoresis buffer. Results demonstrate that unlike DNA in PFCE, the pulsed electric field mainly affects the separation performance of RNA between 0.4 and 2.0 knt. The migration mobility of long RNA fragments is not a strong function of modulation depth and pulsed frequency. Moreover, the logarithm of RNA mobility is almost inversely proportional to the logarithm of molecule size up to 6.0 knt with correlation coefficient higher than 0.99 in all the polymer concentrations measured here. Resonance frequency of RNA in PFCE was also observed. While these initial experiments show no distinct advantages of using PFCE for RNA separation, they do take further step toward characterizing the migration behavior of RNA under pulsed field conditions.

  10. 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.

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

    Science.gov (United States)

    Cheng, Cheanyeh; Nian, Yu-Chuan

    2015-02-06

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

  12. 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.

  13. Characterization of oligosaccharides with capillary high performance anion exchange chromatography hyphenated to pulsed amperometric detection and ion trap mass spectrometry : application to the analysis of human lysosomal disorders

    NARCIS (Netherlands)

    Bruggink, Cornelis

    2013-01-01

    The development of a capillary ion chromatograph is described together with a matching desalter. This desalter made it possible to use on-line a mass spectrometer. The mass spectrometer enables partly to characterize carbohydrates eluting from the anion exchange column. This separation technology is

  14. 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.

  15. 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.

  16. 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.

  17. Electrophoretic separation method for membrane pore-forming proteins in multilayer lipid membranes.

    Science.gov (United States)

    Okamoto, Yukihiro; Tsujimoto, Yusuke; Umakoshi, Hiroshi

    2016-03-01

    In this paper, we report on a novel electrophoretic separation and analysis method for membrane pore-forming proteins in multilayer lipid membranes (MLMs) in order to overcome the problems related to current separation and analysis methods of membrane proteins, and to obtain a high-performance separation method on the basis of specific properties of the lipid membranes. We constructed MLMs, and subsequently characterized membrane pore-forming protein behavior in MLMs. Through the use of these MLMs, we were able to successfully separate and analyze membrane pore-forming proteins in MLMs. To the best of our knowledge, this research is the first example of membrane pore-forming protein separation in lipid membranes. Our method can be expected to be applied for the separation and analysis of other membrane proteins including intrinsic membrane proteins and to result in high-performance by utilizing the specific properties of lipid membranes.

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  19. 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....

  20. 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.

  1. 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

  2. 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.

  3. 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.

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

    OpenAIRE

    2009-01-01

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

  5. 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...... compared with 3.64 among food isolates). The explanation for this may be that more virulent strains are more prone to cause human infection. It is, however, also possible that strains oft. monocytogenes may become more virulent while multiplying in a living organism compared with multiplying in foods....

  6. 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...... control of the formation and arrangement of liquid/liquid phase boundaries. The two immiscible phases which are injected separately into the microchannel are taken from a polyethylene glycol (PEG)-dextran system. The side walls of the channel are partially made of gel material which serves as an ion...

  7. Myosin light chain isoforms retain their species-specific electrophoretic mobility after processing, which enables differentiation between six species: 2DE analysis of minced meat and meat products made from beef, pork and poultry.

    Science.gov (United States)

    Montowska, Magdalena; Pospiech, Edward

    2012-09-01

    Investigation of protein changes as well as authentication of meat is particularly difficult in processed meat products due to their different composition, complexity and very often inhomogeneity. The aim of this study was to check if the inter-species differences in the expression of myosin light chain (MLC) isoforms observed in raw meat were retained in meat products. MLCs from mixtures of minced meat (16 variants), frankfurters and sausages (15 products) made from cattle, pig, chicken, turkey, duck and goose were analysed by 2DE. Species-specific patterns of MLC isoforms were observed in all the mixtures and processed meat products. Relatively small degradation was observed in the MLCs after processing. Image analysis enabled species identification of the meat in all samples when the content of meat of one species was not lower than 10%. However, it was impossible to differentiate between all the six species under investigation on the basis of individual isoform. It was possible when the combination of all the three isoforms (myosin light chain 1 fast, myosin light chain 2 fast and myosin light chain 3 fast) was analysed. The results evidenced that MLCs have potential to be used as markers in authentication of meat products made from the analysed six species.

  8. Simulated null-gravity environments as applied to electrophoretic separations of biological species

    Science.gov (United States)

    Giannovario, J. A.; Griffin, R. N.

    1978-01-01

    The scale-up of electrophoretic separations to provide preparative quantities of materials has been hampered by gravity induced convection and sedimentation. The separation of biologically important species may be significantly enhanced by electrophoretic space processing. Simple demonstrations on past space flights have proven some principles. Several techniques have been evolved to study electrophoretic separations where the effects of gravity have been nullified or significantly reduced. These techniques employ mechanical design, density gradients and computer modeling. Utilization of these techniques for ground based studies will yield clues as to which biological species can be considered prime candidates for electrophoretic processing in zero-G.

  9. Review of UV spectroscopic, chromatographic, and electrophoretic methods for the cholinesterase reactivating antidote pralidoxime (2-PAM).

    Science.gov (United States)

    John, Harald; Blum, Marc-Michael

    2012-01-01

    Pralidoxime (2-PAM) belongs to the class of monopyridinium oximes with reactivating potency on cholinesterases inhibited by phosphylating organophosphorus compounds (OPC), for example, pesticides and nerve agents. 2-PAM represents an established antidote for the therapy of anticholinesterase poisoning since the late 1950s. Quite high therapeutic concentrations in human plasma (about 13 µg/ml) lead to concentrations in urine being about 100 times higher allowing the use of less sensitive analytical techniques that were used especially in the early years after 2-PAM was introduced. In this time (mid-1950s until the end of the 1970s) 2-PAM was most often analyzed by either paper chromatography or simple UV spectroscopic techniques omitting any sample separation step. These methods were displaced completely after the establishment of column liquid chromatography in the early 1980s. Since then, diverse techniques including cation exchange, size-exclusion, reversed-phase, and ligand-exchange chromatography have been introduced. Today, the most popular method for 2-PAM quantification is ion pair chromatography often combined with UV detection representing more than 50% of all column chromatographic procedures published. Furthermore, electrophoretic approaches by paper and capillary zone electrophoresis have been successfully used but are seldom applied. This review provides a commentary and exhaustive summary of analytical techniques applied to detect 2-PAM in pharmaceutical formulations and biological samples to characterize stability and pharmacokinetics as well as decomposition and biotransformation products. Separation techniques as well as diverse detectors are discussed in appropriate detail allowing comparison of individual preferences and limitations. In addition, novel data on mass spectrometric fragmentation of 2-PAM are provided.

  10. Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kazarian, Artaches A. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); W.M. Keck FT-ICR-MS Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Sanz Rodriguez, Estrella; Deverell, Jeremy A. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); McCord, James; Muddiman, David C. [W.M. Keck FT-ICR-MS Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Paull, Brett, E-mail: Brett.Paull@utas.edu.au [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia); ARC Centre of Excellence for Electromaterials Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001 (Australia)

    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{sup −1} levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min{sup −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{sup −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%. - Highlights: • Novel PS-DVB modified photonic crystal fibres for in-capillary micro-extraction. • New method for micro-extraction of PAHs and HPLC-FL detection at sub-ppb levels. • Demonstration of PS-DVB modified photonic crystal fibres for capillary bioseparations.

  11. 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.

  12. Capillary flow solder wettability test

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Rejent, J.A.

    1996-01-01

    A test procedure was developed to assess the capillary flow wettability of solders inside of a confined geometry. The test geometry was comprised of two parallel plates with a controlled gap of constant thickness (0.008 cm, 0.018 cm, 0.025 cm, and 0.038 cm). Capillary flow was assessed by: (1) the meniscus or capillary rise of the solder within the gap, (2) the extent of void formation in the gap, and (3) the time-dependence of the risen solder film. Tests were performed with the lead-free solders.

  13. 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.

  14. Capillary electrophoresis-mass spectrometry of carbohydrates.

    Science.gov (United States)

    Zaia, Joseph

    2013-01-01

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

  15. 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.

  16. 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.

  17. 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.

  18. Characterization of CdTe films deposited at various bath temperatures and concentrations using electrophoretic deposition.

    Science.gov (United States)

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

    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 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.

  19. 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

  20. Analysis of inflammatory response in human plasma samples by an automated multicapillary electrophoresis system.

    Science.gov (United States)

    Larsson, Anders; Hansson, Lars-Olof

    2004-01-01

    A new automated multicapillary zone electrophoresis instrument with a new high-resolution (HR) buffer (Capillarys with HR buffer) for analysis of human plasma proteins was evaluated. Albumin, alpha(1)-antitrypsin, alpha(1)-acid glycoprotein, haptoglobin, fibrinogen, immunoglobulin (Ig)A, IgG and IgM were determined nephelometrically in 200 patient plasma samples. The same samples were then analyzed on the Capillarys system (Sebia, Paris, France). The albumin concentration from the nephelometric determination was used for quantification of the individual peaks in the capillary electrophoresis (CE) electropherogram. There was strong linear correlation between the nephelometric and electrophoretic determination of alpha(1)-antitrypsin (R(2) = 0.906), alpha(1)-acid glycoprotein (R(2) =0.894) and haptoglobin (R(2) = 0.913). There was also good correlation between the two determinations of gamma-globulins (R(2) = 0.883), while the correlation was weaker for fibrinogen (R(2) = 0.377). The Capillarys instrument is a reliable system for plasma protein analysis, combining the advantages of full automation, good analytical performance and high throughput. The HR buffer in combination with albumin quantification allows the simultaneous quantification of inflammatory markers in plasma samples without the need for nephelometric determination of these proteins.

  1. Demonstrating Electrophoretic Separation in a Straight Paper Channel Delimited by a Hydrophobic Wax Barrier

    Science.gov (United States)

    Xu, Chunxiu; Lin, Wanqi; Cai, Longfei

    2016-01-01

    A demonstration is described of electrophoretic separation of carmine and sunset yellow with a paper-based device. The channel in the paper device was fabricated by hand with a wax pen. Electrophoretic separation of carmine and sunset yellow was achieved within a few minutes by applying potential on the channel using a simple and inexpensive power…

  2. 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.

  3. Separation and Analysis of Organic Acids in Food by Capillary Silica Monolithic Column%毛细管硅胶整体柱分离分析食品中有机酸

    Institute of Scientific and Technical Information of China (English)

    高文惠; 杨桂君; 贾英民

    2012-01-01

    A capillary electrochromatographic method for the separation and analysis of organic acids in food was proposed using a capillary silica monolithic column.Optimization of experimental parameters that influence separation efficiency was carried out.A capillary silica monolithic C18 column was prepared in our lab for the separation of organic acids using a mobile phase(pH 5.2) consisting of 150 mmol/L sodium dihydrogen phosphate-60 mmol/L borax buffer solution with a final concentration of 5:2 in the mixture and 0.5 mmol/L cetyl trimethyl ammonium bromide.Other experimental conditions were as follows: voltage-6 kV;injection time 10 s;column temperature 25 ℃;and detection wavelength 200 nm.Results showed that the linear range was 10–1000 μg/mL for oxalic acid and fumaric acid,20–500 μg/mL for succinic acid,15–1000 μg/mL for tartaric acid and citric acid.The average recovery rates for the organic acids were between 89.8% and 101.1%,with a relative standard deviation(RSD) less than or equal to 6.23%(n = 5).The detection limits of the proposed methods were between 3.0 and 7.5 μg/mL.In conclusion,capillary silica monolithic column is inexpensive,stable to heat and organic solvents,and repeatedly usable.Capillary electrochromatography with capillary silica monolithic column allows simple,rapid and effective separation and analysis of organic acids in food.%建立应用毛细管硅胶整体柱采用毛细管电色谱法分离分析食品中有机酸的方法。对影响毛细管电色谱分离效率的条件进行优化,色谱柱为本实验室制作的毛细管硅胶整体C18柱(100μm×40cm)、电压-6kV、进样时间10s、紫外检测波长200nm,流动相为150mmol/L磷酸二氢钠-60mmol/L硼砂缓冲溶液(浓度比为5:2)和0.5mmol/L十六烷基三甲基溴化铵,pH7.5、25℃。结果表明:草酸和富马酸的线性范围为10~1000μg/mL,丁二酸线性范围20~500μg/mL,酒石酸和柠檬酸的线性范围为15~1000μg

  4. 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.

  5. 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.

  6. 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.

  7. Novel cationic polyelectrolyte coatings for capillary electrophoresis.

    Science.gov (United States)

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

    2016-01-01

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

  8. Ultra-high aspect ratio Si nanowires fabricated with plasma etching: plasma processing, mechanical stability analysis against adhesion and capillary forces and oleophobicity

    Science.gov (United States)

    Zeniou, A.; Ellinas, K.; Olziersky, A.; Gogolides, E.

    2014-01-01

    Room-temperature deep Si etching using time-multiplexed deep reactive ion etching (DRIE) processes is investigated to fabricate ultra-high aspect ratio Si nanowires (SiNWs) perpendicular to the silicon substrate. Nanopatterning is achieved using either top-down techniques (e.g. electron beam lithography) or colloidal polystyrene (PS) sphere self-assembly. The latter is a faster and more economical method if imperfections in diameter and position can be tolerated. We demonstrate wire radii from below 100 nm to several micrometers, and aspect ratios (ARs) above 100:1 with etching rates above 1 μm min-1 using classical mass flow controllers with pulsing rise times of seconds. The mechanical stability of these nanowires is studied theoretically and experimentally against adhesion and capillary forces. It is shown that above ARs of the order of 50:1 for spacing 1 μm, SiNWs tend to bend due to adhesion forces between them. Such large adhesion forces are due to the high surface energy of silicon. Wetting the SiNWs with water and drying also gives rise to capillary forces. We find that capillary forces may be less important for SiNW collapse/bending compared to adhesion forces of dry SiNWs, contrary to what is observed for polymeric nanowires/nanopillars which have a much lower surface energy compared to silicon. Finally we show that SiNW arrays have oleophobic and superoleophobic properties, i.e. they exhibit excellent anti-wetting properties for a wide range of liquids and oils due to the re-entrant profile produced by the DRIE process and the well-designed spacing.

  9. 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.

  10. 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 $N$.

  11. Electrophoretic deposition of nickel zinc ferrite nanoparticles into microstructured patterns

    Directory of Open Access Journals (Sweden)

    Stefan J. Kelly

    2016-05-01

    Full Text Available Using DC electric fields, nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4 nanoparticles (Dh =16.6 ± 3.6 nm are electrophoretically deposited onto silicon substrates to form dense structures defined by photoresist molds. Parameters such as electric field, bath composition, and deposition time are tuned to produce films ranging in thickness from 177 to 805 nm. The deposited films exhibit soft magnetic properties with a saturation magnetization of 60 emu/g and a coercivity of 2.6 kA/m (33 Oe. Additionally, the influence of the photoresist mold on the deposit profile is studied, and patterned films with different shapes (lines, squares, circles, etc. are demonstrated with feature sizes down to 5 μm.

  12. 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.

  13. Design of colored multilayered electrophoretic particles for electronic inks.

    Science.gov (United States)

    Badila, M; Hébraud, A; Brochon, C; Hadziioannou, G

    2011-09-01

    The preparation of multilayered latex particles with surface functional groups suitable for use as electrophoretic particles in electronic inks has been studied. The particles are formed by dispersion polymerization and have a polystyrene core, slightly cross-linked with divinylbenzene (DVB), and a poly(methyl methacrylate) (PMMA) or a poly(acrylic acid) (PAA) shell. After grafting alkyl chains on their surface, the particles are negatively or positively charged and sterically stabilized against aggregation in nonpolar solvent. The particles were dyed by incorporation of Nigrosin during polymerization or by swelling in supercritical CO(2) in the presence of a dye. Particle size, morphology, incorporated dye content and zeta potential were determined. A dual-particle electronic ink based on a mixture of the colored multilayered particles and white hybrid TiO(2)-polymer particles was prepared and electro-optically tested.

  14. Electrophoretic molecular karyotype of the dermatophyte Trichophyton rubrum

    Directory of Open Access Journals (Sweden)

    Cervelatti Eliane P.

    2004-01-01

    Full Text Available The electrophoretic karyotype of the dermatophyte Trichophyton rubrum was established using contour-clamped homogeneous electric field (CHEF gel electrophoresis. Five chromosomal bands of approximately 3.0 to 5.8 megabase pairs (Mbp each were observed and together indicated that 22.05 Mbp of the total genome are organized as chromosomal macromolecules. In addition to establishing the number and size of T. rubrum chromosomes, these results open perspectives for the construction of chromosome-specific libraries and for the physical mapping of genes of interest, thus permitting future gene linkage studies in this pathogen. A detailed understanding of the karyotype and genomic organization of T. rubrum should contribute to further genetic, taxonomic and epidemiological studies of this dermatophyte.

  15. On-column labeling of gram-positive bacteria with a boronic acid functionalized squarylium cyanine dye for analysis by polymer-enhanced capillary transient isotachophoresis.

    Science.gov (United States)

    Saito, Shingo; Massie, Tara L; Maeda, Takeshi; Nakazumi, Hiroyuki; Colyer, Christa L

    2012-03-06

    A new asymmetric, squarylium cyanine dye functionalized by boronic acid ("SQ-BA") was designed and synthesized for on-capillary labeling of gram-positive bacteria to provide for high sensitivity detection by way of a modified form of capillary electrophoresis with laser induced fluorescence detection (CE-LIF). The CE-based separation employed a polymer-enhanced buffer with capillary transient isotachophoresis in a new hybrid method dubbed "PectI." It was found that the addition of various monosaccharides to SQ-BA in a batch aqueous solution greatly enhanced the emission of the boronic acid functionalized dye by a factor of up to 18.3 at a long wavelength (λ(ex) = 630 nm, λ(em) = 660 nm) with a high affinity constant (K = ~10(2.80) M(-1)) superior to other sugar probes. Semiempirical quantum mechanics calculations suggest that the mechanism for this high enhancement may involve the dissociation of initially nonemissive dye associates (stabilized by an intramolecular hydrogen bond) upon complex formation with sugars. The fluorescence emission of SQ-BA was also significantly enhanced in the presence of a gram-positive bacterial spore, Bacillus globigii (Bg), which serves as a simulant of B. anthracis (or anthrax) and which possesses a peptidoglycan (sugar)-rich spore coat to provide ample sites for interaction with the dye. Several peaks were observed for a pure Bg sample even with polyethyleneoxide (PEO) present in the CE separation buffer, despite the polymer's previously demonstrated ability to focus microoorganisms to a single peak during migration. Likewise, several peaks were observed for a Bg sample when capillary transient isotachophoresis (ctITP) alone was employed. However, the new combination of these techniques as "PectI" dramatically and reproducibly focused the bacteria to a single peak with no staining procedure. Using PectI, the trace detection of Bg spores (corresponding to approximately three cells per injection) along with separation efficiency

  16. Online analysis of europium and gadolinium species complexed or uncomplexed with humic acid by capillary electrophoresis-inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Kautenburger, Ralf; Nowotka, Karsten; Beck, Horst Philipp

    2006-03-01

    Detailed information on the geochemical behavior of radioactive and toxic metal ions under environmental conditions (in geological matrices and aquifer systems) is needed in order to assess the long-term safety of waste repositories. This includes knowledge of the mechanisms of relevant geochemical reactions, as well as associated thermodynamic and kinetic data. Several previous studies have shown that humic acid can play an important role in the immobilization or mobilization of metal ions due to complexation and colloid formation. In our project we investigate the complexation behavior of (purified Aldrich) humic acid and its influence on the migration of the lanthanides europium and gadolinium (homologs of the actinides americium and curium) in the ternary system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) under almost natural conditions. Capillary electrophoresis (CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was hyphenated with a homemade interface to inductively coupled plasma mass spectrometry (ICP-MS, VG Elemental PlasmaQuad 3) giving a system that is highly sensitive to the rare-earth element species of europium and gadolinium with humic acid. The humic acid used was also halogenated with iodine, which acted as an ICP-MS marker. To couple CE to ICP-MS, a fused silica CE capillary was flexibly fitted into a MicroMist 50 mul nebulizer with a Cinnabar cyclonic spray chamber in the external homemade interface. The chamber was chilled to a temperature of 4 degrees C to optimize the sensitivity. 200 ppb of cesium were added to the CE separation buffer so that the capillary flow could be observed. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within the interface in order to get a fluid throughput high enough to maintain continuous nebulization. Very low detection limits were achieved: 125 ppt for 153Eu and 250 ppt for 158Gd. Using this optimized CE

  17. Simulations of electrophoretic RNA transport through transmembrane carbon nanotubes.

    Science.gov (United States)

    Zimmerli, Urs; Koumoutsakos, Petros

    2008-04-01

    The study of interactions between carbon nanotubes and cellular components, such as membranes and biomolecules, is fundamental for the rational design of nanodevices interfacing with biological systems. In this work, we use molecular dynamics simulations to study the electrophoretic transport of RNA through carbon nanotubes embedded in membranes. Decorated and naked carbon nanotubes are inserted into a dodecane membrane and a dimyristoylphosphatidylcholine lipid bilayer, and the system is subjected to electrostatic potential differences. The transport properties of this artificial pore are determined by the structural modifications of the membrane in the vicinity of the nanotube openings and they are quantified by the nonuniform electrostatic potential maps at the entrance and inside the nanotube. The pore is used to transport electrophoretically a short RNA segment and we find that the speed of translocation exhibits an exponential dependence on the applied potential differences. The RNA is transported while undergoing a repeated stacking and unstacking process, affected by steric interactions with the membrane headgroups and by hydrophobic interaction with the walls of the nanotube. The RNA is structurally reorganized inside the nanotube, with its backbone solvated by water molecules near the axis of the tube and its bases aligned with the nanotube walls. Upon exiting the pore, the RNA interacts with the membrane headgroups and remains attached to the dodecane membrane while it is expelled into the solvent in the case of the lipid bilayer. The results of the simulations detail processes of molecular transport into cellular compartments through manufactured nanopores and they are discussed in the context of applications in biotechnology and nanomedicine.

  18. 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

  19. Two-dimensional capillary electrophoresis using tangentially connected capillaries.

    Science.gov (United States)

    Sahlin, Eskil

    2007-06-22

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

  20. Capillary electrophoresis analysis of different variants of the amyloidogenic protein β2 -microglobulin as a simple tool for misfolding and stability studies.

    Science.gov (United States)

    Bertoletti, Laura; Bisceglia, Federica; Colombo, Raffaella; Giorgetti, Sofia; Raimondi, Sara; Mangione, P Patrizia; De Lorenzi, Ersilia

    2015-10-01

    Free solution capillary electrophoresis with UV detection is here used to retrieve information on the conformational changes of wild-type β2 -microglobulin and a series of naturally and artificially created variants known to have different stability and amyloidogenic potential. Under nondenaturing conditions, the resolution of at least two folding conformers at equilibrium is obtained and a third species is detected for the less stable isoforms. Partial denaturation by using chaotropic agents such as acetonitrile or trifluoroethanol reveals that the separated peaks are at equilibrium, as the presence of less structured species is either enhanced or induced at the expenses of the native form. Reproducible CE data allow to obtain an interesting semiquantitative correlation between the peak areas observed and the protein stability. Thermal unfolding over the range 25-42°C is induced inside the capillary for the two pathogenic proteins (wtβ2 -microglobulin and D76N variant): the large differences observed upon small temperature variation draw attention on the robustness of analytical methods when dealing with proteins prone to misfolding and aggregation.

  1. 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.

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

    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 10-8 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.

  3. Fast capillary electrophoresis-laser induced fluorescence analysis of ligase chain reaction products: human mitochondrial DNA point mutations causing Leber's hereditary optic neuropathy.

    Science.gov (United States)

    Muth, J; Williams, P M; Williams, S J; Brown, M D; Wallace, D C; Karger, B L

    1996-12-01

    High speed capillary electrophoresis-laser-induced fluorescence (CE-LIF) has been used to separate and detect point mutations using the ligase chain reaction (LCR). The method utilizes short capillary columns (7.5 cm effective length) and fields of 400 V/cm to analyze DNA-ethidium bromide complexes using an He/Ne laser. The method was first demonstrated with a commercially available kit for LCR based on a lacI gene fragment inserted in a Bluescript II phagemid. LCR-CE-LIF was then applied to detect point mutations in human mitochondrial DNA, resulting in Leber's hereditary optic neuropathy (LHON). Three severe mutations were analyzed in which the original base is substituted by a thymidine base at positions 3460, 11778 and 14459. Appropriate primers were designed with polyT tails for length discrimination of pooled samples. Successful detection of mutated samples was achieved, with appropriate correction for small amounts of nonspecific ligated product. The method is rapid, easy to implement, and automatable.

  4. 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.

  5. A fully automated linear polyacrylamide coating and regeneration method for capillary electrophoresis of proteins.

    Science.gov (United States)

    Bodnar, Judit; Hajba, Laszlo; Guttman, Andras

    2016-12-01

    Surface modification of the inner capillary wall in CE of proteins is frequently required to alter EOF and to prevent protein adsorption. Manual protocols for such coating techniques are cumbersome. In this paper, an automated covalent linear polyacrylamide coating and regeneration process is described to support long-term stability of fused-silica capillaries for protein analysis. The stability of the resulting capillary coatings was evaluated by a large number of separations using a three-protein test mixture in pH 6 and 3 buffer systems. The results were compared to that obtained with the use of bare fused-silica capillaries. If necessary, the fully automated capillary coating process was easily applied to regenerate the capillary to extend its useful life-time.

  6. 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%.

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

    Science.gov (United States)

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

    2012-03-10

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

  9. On-line cation-exchange preconcentration and capillary electrophoresis coupled by tee joint interface.

    Science.gov (United States)

    Zhang, Zhao-Xiang; He, You-Zhao

    2005-02-25

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

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

    Science.gov (United States)

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

    2015-04-21

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

  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. Capillary imbibition in parallel tubes

    Science.gov (United States)

    McRae, Oliver; Ramakrishnan, T. S.; Bird, James

    2016-11-01

    In modeling porous media two distinct approaches can be employed; the sample can be examined holistically, using global variables such as porosity, or it can be treated as a network of capillaries connected in series to various intermediate reservoirs. In forced imbibition this series-based description is sufficient to characterize the flow, due to the presence of an externally maintained pressure difference. However, in spontaneous imbibition, flow is driven by an internal capillary pressure, making it unclear whether a series-based model is appropriate. In this talk, we show using numerical simulations the dynamics of spontaneous imbibition in concentrically arranged capillary tubes. This geometry allows both tubes access to a semi-infinite reservoir but with inlets in close enough proximity to allow for interference. We compare and contrast the results of our simulations with theory and previous experiments. Schlumberger-Doll Research.

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

    Science.gov (United States)

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

    2015-09-01

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

  15. Capillary interactions in Pickering emulsions

    Science.gov (United States)

    Guzowski, J.; Tasinkevych, M.; Dietrich, S.

    2011-09-01

    The effective capillary interaction potentials for small colloidal particles trapped at the surface of liquid droplets are calculated analytically. Pair potentials between capillary monopoles and dipoles, corresponding to particles floating on a droplet with a fixed center of mass and subjected to external forces and torques, respectively, exhibit a repulsion at large angular separations and an attraction at smaller separations, with the latter resembling the typical behavior for flat interfaces. This change of character is not observed for quadrupoles, corresponding to free particles on a mechanically isolated droplet. The analytical results are compared with the numerical minimization of the surface free energy of the droplet in the presence of spherical or ellipsoidal particles.

  16. Analysis of five alkaloids using surfactant-coated multi-walled carbon nanotubes as the pseudostationary phase in nonaqueous capillary electrophoresis.

    Science.gov (United States)

    Hou, Jingyi; Li, Geng; Wei, Yingqin; Lu, Heng; Jiang, Chao; Zhou, Xiaoteng; Meng, Fanyun; Cao, Jun; Liu, Jinxin

    2014-05-23

    In this paper, surfactant-coated multi-walled carbon nanotubes (SC-MWNTs) have been proposed as a novel pseudostationary phase (PSP) to enhance the separation of isoquinoline alkaloids in nonaqueous capillary electrophoresis (NACE). Several parameters affecting NACE separation were studied including the MWNT concentration, the electrolyte concentration, pH* and the separation voltage. In comparison to conventional NACE, the addition of an MWNT dispersion using surfactant solutions in the electrolyte produced an important enhancement in the resolution due to the π-π interactions between the analytes and the surface of the carbon nanotubes. Using SC-MWNTs (6μgmL(-1)) as a PSP in the background electrolyte (BGE) (i.e., 20mM sodium acetate in methanol-acetonitrile (80:20, v/v)) provided the complete separation of five alkaloids. Finally, the developed method has been successfully applied to the detection and quantification of the tested compounds of Rhizoma Coptidis.

  17. 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.

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

    Science.gov (United States)

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

    2008-07-15

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

  19. 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.

  20. Optimization of affinity capillary electrophoresis for routine investigations of protein-metal ion interactions.

    Science.gov (United States)

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

    2015-10-01

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

  1. 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.

  2. Analytical quality by design in the development of a cyclodextrin-modified capillary electrophoresis method for the assay of metformin and its related substances.

    Science.gov (United States)

    Orlandini, Serena; Pasquini, Benedetta; Gotti, Roberto; Giuffrida, Alessandro; Paternostro, Ferdinando; Furlanetto, Sandra

    2014-09-01

    Quality by Design (QbD) is a new paradigm of quality to be applied to pharmaceutical products and processes, recently encouraged by International Conference on Harmonisation guidelines. In this paper QbD approach was applied to the development of a CE method for the simultaneous assay of metformin hydrochloride (MET) and its main impurities. QbD strategy was focused on electrophoretic process understanding, and the analytical method was thoroughly evaluated by applying risk assessment and chemometric tools. Method scouting allowed CD-CZE based on the addition of carboxymethyl-β-CD to Britton-Robinson acidic buffer to be chosen as operative mode. Seven critical process parameters (CPPs) were selected, related to capillary, injection, BGE and instrumental settings. The effect of the different levels of the CPPs on critical quality attributes (CQAs), e.g. critical resolution values and analysis time, was evaluated in a screening study. Response surface methodology led to draw contour plots and sweet spot plots. The definition of design space was accomplished by applying Monte-Carlo simulations, thus identifying by risk of failure maps a multivariate zone where the CQAs fulfilled the requirements with a selected probability. Finally, a control strategy was designed and the method was applied to a real sample of MET tablets.

  3. 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%.

  4. 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.

  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. Origami paper-based fluidic batteries for portable electrophoretic devices.

    Science.gov (United States)

    Chen, Sung-Sheng; Hu, Chih-Wei; Yu, I-Fan; Liao, Ying-Chih; Yang, Jing-Tang

    2014-06-21

    A manufacturing approach for paper-based fluidic batteries was developed based on the origami principle (three-dimension paper folding). Microfluidic channels were first created on a filter paper by a wax-printing method. Copper and aluminium sheets were then glued onto the paper as electrodes for the redox reaction. After the addition of copper sulphate and aluminium chloride, commonly available cellophane paper was attached as a membrane to separate the two electrodes. The resulting planar paper sheets were then folded into three-dimensional structures and compiled as a single battery with glue. The two half reactions (Al/Al(3+) and Cu/Cu(2+)) in the folded batteries provided an open-circuit potential from 0.82 V (one cell) to 5.0 V (eight cells in series) depending on the origami design. The prepared battery can provide a stable current of 500 μA and can light a regular LED for more than 65 min. These paper-based fluidic batteries in a set can also be compiled into a portable power bank to provide electric power for many electric or biomedical applications, such as LED lights and electrophoretic devices, as we report here.

  7. Alumina/Ce-Tzp Functionally Graded Materials by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    C.Zhao, J.Vleugels; O.Van Der Biest

    2000-01-01

    Cylindrical Al2O3/Ce-TZP functionally graded composites were fabricated by electrophoretic deposition and pressureless sintering in air. A continuous change in composition was realized by changing the composition of the suspension during deposition. In order to achieve full densification, a temperature above 1550℃ was necessary. The resultant FGM cylinder with a diameter of 5.6 mm shows the following structure: a central hole with a diameter less than 0.5 mm, a tough Ce-ZrO2 core with a diameter of about 3 mm, a gradient layer of about 1 mm, and a hard Al2O3-rich surface layer. The Ce-ZrO2 core has a Vickers hardness between 10and 11 GPa and an excellent toughness (>10 MPa√m). In the gradient layer, hardness and toughness vary continuously along the radius. The surface layer has a hardness of 15.5 GPa and a modest toughness of 2.5MPa√m.

  8. [Electrophoretic studies of serum protein fractions in horses with laminitis].

    Science.gov (United States)

    Edinger, H; Miller, I; Stanek, C; Gemeiner, M

    1992-10-01

    The spectrum of serum proteins was evaluated in 46 horses affected with spontaneous laminitis and correlations between the severity of the disease and changes of the protein pattern were analyzed. The investigation was made in two groups; group A consisted of 21 horses of various breeds (warmblood, thoroughbred, standardbred) and group B of 25 ponys. Each group was subdivided according to the severity of the disease, using the OBEL-grade (OG) classification system. Serum proteins were separated by different one- and two-dimensional electrophoretic methods. Sera analysed by cellulose acetate electrophoresis showed a significant difference in the alpha 1-globulin fraction between OG II and OG IV affected horses. An increasing severity of the disease was correlated with a decrease of the alpha 1-globulins. The other protein fractions didn't show a uniform tendency. In group B there was a significant difference in the alpha 1-globulin fractions of OG II and OG III and in the beta 2-globulin fractions of OG I and OG II affected ponys. The acute phase proteins C3c, C4, Hp and fibronectin could be determined in a preliminary study in horse serum using the cross-reactivity of antibodies against the homologous human proteins.

  9. 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.

  10. 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

    2009-09-09

    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.

  11. Electrophoretic mobility patterns of collagen following laser welding

    Science.gov (United States)

    Bass, Lawrence S.; Moazami, Nader; Pocsidio, Joanne O.; Oz, Mehmet C.; LoGerfo, Paul; Treat, Michael R.

    1991-06-01

    Clinical application of laser vascular anastomosis in inhibited by a lack of understanding of its mechanism. Whether tissue fusion results from covalent or non-covalent bonding of collagen and other structural proteins is unknown. We compared electrophoretic mobility of collagen in laser treated and untreated specimens of rat tail tendon (>90% type I collagen) and rabbit aorta. Welding was performed, using tissue shrinkage as the clinical endpoint, using the 808 nm diode laser (power density 14 watts/cm2) and topical indocyanine green dye (max absorption 805 nm). Collagen was extracted with 8 M urea (denaturing), 0.5 M acetic acid (non-denaturing) and acetic acid/pepsin (cleaves non- helical protein). Mobility patterns on gel electrophoresis (SDS-PAGE) after urea or acetic acid extraction were identical in the lasered and control tendon and vessel (confirmed by optical densitometry), revealing no evidence of formation of novel covalent bonds. Alpha and beta band intensity was diminished in pepsin incubated lasered specimens compared with controls (optical density ratio 0.00 +/- 9 tendon, 0.65 +/- 0.12 aorta), indicating the presence of denatured collagen. With the laser parameters used, collagen is denatured without formation of covalent bonds, suggesting that non-covalent interaction between denatured collagen molecules may be responsible for the weld. Based on this mechanism, welding parameters can be chosen which produce collagen denaturation without cell death.

  12. Electrophoretic High Molecular Weight DNA Purification Enables Optical Mapping

    Science.gov (United States)

    Maydan, Jason; Thomas, Matthew; Tabanfar, Leyla; Mai, Laura; Poon, Hau-Ling; Pe, Joel; Hahn, Kristen; Goji, Noriko; Amoako, Kingsley; Marziali, Andre; Hanson, Dan

    2013-01-01

    Optical mapping generates an ordered restriction map from single, long DNA molecules. By overlapping restriction maps from multiple molecules, a physical map of entire chromosomes and genomes is constructed, greatly facilitating genome assembly in next generation sequencing projects, comparative genomics and strain typing. However, optical mapping relies on a method of preparing high quality DNA >250 kb in length, which can be challenging from some organisms and sample types. Here we demonstrate the ability of Boreal Genomics' Aurora instrument to provide pure, high molecular weight (HMW) DNA 250-1,100 kb in length, ideally suited for optical mapping. The Aurora performs electrophoretic DNA purification within an agarose gel in reusable cartridges, protecting long DNA molecules from shearing forces associated with liquid handling steps common to other purification methods. DNA can be purified directly from intact cells embedded and lysed within an agarose gel, preserving the highest molecular weight DNA possible while achieving exceptional levels of purity. The Aurora delivers DNA in a buffer solution, where DNA can be condensed and protected from shearing during recovery with a pipette. DNA is then returned to its regular coiled state by simple dilution prior to optical mapping. Here we present images showing HMW DNA purification taking place in the Aurora and subsequent images of single DNA molecules on OpGen's Argus® Optical Mapping System. Future work will focus on further optimizing Aurora HMW DNA purification to bias DNA recovery in favor of only the longest molecules in a sample, maximizing the benefits of optical mapping.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Filling of charged cylindrical capillaries

    NARCIS (Netherlands)

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

    2014-01-01

    We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because

  18. 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, th...... and quantified. (C) 1999 The Society of Rheology. [S0148-6055(99)00103-0]....

  19. Draft Genome Sequences of Eight Nontypeable Haemophilus influenzae Strains Previously Characterized Using an Electrophoretic Typing Scheme.

    Science.gov (United States)

    Mussa, Huda J; VanWagoner, Timothy M; Morton, Daniel J; Seale, Thomas W; Whitby, Paul W; Stull, Terrence L

    2015-11-25

    Nontypeable Haemophilus influenzae is an important cause of human disease. Strains were selected for genome sequencing to represent the breadth of nontypeable strains within the species, as previously defined by the electrophoretic mobility of 16 metabolic enzymes.

  20. Improved design of electrophoretic equipment for rapid sickle-cell-anemia screening

    Science.gov (United States)

    Reddick, J. M.; Hirsch, I.

    1974-01-01

    Effective mass screening may be accomplished by modifying existing electrophoretic equipment in conjunction with multisample applicator used with cellulose-acetate-matrix test paper. Using this method, approximately 20 to 25 samples can undergo electrophoresis in 5 to 6 minutes.