bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capillary electrophoresis‐based separation of transferrin sialoforms in patients with carbohydrate‐deficient glycoprotein syndrome
Authors: Oda Robert P. , Prasad Rajani , Stout Robert L. , Coffin David , Patton Wendy P. , Kraft Daniel L. , O'Brien John F. , Landers James P. 
Published: May 2005

AbstractThe heterogeneity associated with protein glycoforms has been a challenge to analytical chemists and the subject of structure‐function studies for biochemists since their presence in biological systems had been confirmed some three decades ago. Initial investigations led to discoveries of synthetic and degradative pathways, and brief forays into functional determination of the “glyco” portion on the protein activity in glycoproteins. Only recently has it come to our understanding that variations from the “normal” glycosylation patterns might be indicative of pathological states. The presence of certain transferrin (Tf) glycoforms in human serum has been shown to correlate with certain clinical syndromes. Hence, the ability to separate and quantitatively measure the various forms of human Tf has become increasingly important. It this study, we demonstrate that a simple method utilizing a DB‐17‐coated capillary to slow endoosmotic flow and a sieving buffer containing hydroxyethyl cellulose allows for the resolution of sialoforms of transferrin. An analysis time of less than eight minutes allows for baseline resolution of the lower sialoforms of Tf, presenting a simple, rapid test for carbohydrate‐deficient transferrin (CDT). We demonstrate the utility of this methodology for the facile diagnosis of carbohydrate‐deficient glycoprotein syndrome, and postulate that it may allow for the detection of other carbohydrate‐deficient protein‐related disease states.
Micellar electrokinetic capillary chromatography (MECC) of UV‐absorbing constituents in normal urine: A chemometric optimisation of the separation
Authors: Alfazema Luwiza N. , Hows Mark E. P. , Howells Sian , Perrett David 
Published: May 2005

AbstractA micellar electrokinetic capillary chromatography (MECC) method when compared to free solution capillary electrophoresis (CZE) was shown to offer improved selectivity and resolution for the separation of UV‐absorbing components of human urine. Some of the factors affecting MECC separation e.g. methanol concentration, sodium dodecyl sulphate (SDS) concentration, β‐cyclodextrin (β‐CD) concentration, voltage, pH, temperature and electrolyte additives (urea, β‐CD and Brij 35) were optimised using chemometric techniques. Three‐level three‐factor (33) factorial designs and simplex optimisation were used to achieve optimised conditions with the goal of obtaining the maximum number of peaks in the shortest possible analysis time. Using a TSP CE2000 instrument with detection from 195–300 nm and fitted with a 75 μm × 44 cm (37 cm effective length) fused silica capillary the final optimum conditions were found to be, an electrolyte consisting of 30 mM sodium tetraborate, pH 10, containing 75 mM SDS and 10 mM β‐CD, 15°C, 20 kV, 4 s hydrodynamic injection of filtered urine. These conditions were capable of separating 70 peaks from a normal human urine pool in less than 12 min. The separation of components in urine using the optimised MECC was simpler, more reproducible, faster and gave better resolution than gradient reversed‐phase high performance liquid chromatography This work was first presented at the 4th International Symposium on Capillary Electrophoresis, University of York, UK, August 1996
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A biostatistical study into the efficiency of individualisation using nonisotopic chemiluminescent‐enhanced NICE™ multilocus DNA probes
Authors: Hau Peter P. C. , Watt Elizabeth H. , Hau Cathyrn M. 
Published: May 2005

AbstractThe efficiency of individualisation using nonisotopic chemiluminescent‐ enhanced probes (NICE™) was investigated by analysing DNA fingerprints obtained from 190 unrelated Caucasians. Novel analysis of the scoring procedure enabled us to include the comparison of 585 pairs of samples for each of two probes. When the results of NICE probes 33.6 and 33.15 were combined, the mean percentage band share between two unrealated individuals was 16.8% and the mean number of bands identified in an individual DNA fingerprint was 54.8. Results were compared with those obtained using isotopically labelled probes and suggest that the two labelling systems gave similar efficiencies for differentiating between individuals. Analysis of DNA fingerprints from 37 family trios (mother, child and father groups) gave a mutation rate of 0.10% when using NICE probes. The two labelling systems compared were equally efficient in establishing family relationships.
Improved sensitivity of detection with the commercial automated gel electrohoresis (HPGE‐1000) apparatus through modification of its optical system
Authors: Yarmola Elena , Chrambach Andreas 
Published: May 2005

AbstractIn a representative application to a fluorescently detectable protein of commercial automated gel electrophoresis apparatus (HPGE‐1000, LabIntelligence, Belmont, CA) the sensitivity of detection by fluorescence was significantly increased by elimination of the mirror below the gel tray. That increase in detection sensitivity is due to a decrease of fluorescent background noise by nearly one order of magnitude, overcompensating a decrease in signal by a factor of two. The resulting increase in signal/noise ratio, i.e., detection sensitivity, should allow for lowered sample loads by which the band width is reduced with benefits to resolution.
The characterization of composite agarose/hydroxyethylcellulose matrices for the separation of DNA fragments using capillary electrophoresis
Authors: Siles Barbara A. , Anderson David E. , Buchanan Nathan S. , Warder Matthew F. 
Published: May 2005

AbstractMixtures of the polysaccharide derivatives, 19% hydroxyethylated SeaPrep agarose (SP‐AG) and hydroxyethylcellulose (HEC), in aqueous buffer solutions are applied for the first time to the separation of DNA fragments using capillary electrophoresis (CE). These matrices form unique size‐sieving networks that allow the separation of a wide size range of DNA fragments in a single analysis. Relative to their homogeneous counterparts, the composite separation matrices provide enhanced selectivity properties of DNA fragments, especially for fragments greater than 1000 base pairs (bp) in length. Additionally, the effects on separation performance of capillary temperature, the incorporation of a DNA intercalator, and applied field strength are demonstrated. Solution viscosity measurements of the homogeneous and composite matrix solutions were made in order to establish the entanglement threshold concentrations for the unique size‐sieving solutions. The relatively low solution viscosities of the composite separation matrices allow reproducible replacement of the separation matrix between analyses. The mechanism of separation of DNA fragments for the composite matrices is proposed.
Micropreparative capillary electrophoresis of DNA by direct transfer onto a membrane
Authors: Magnúsdóttir Soffía , Heller Christoph , Sergot Phillipe , Viovy Jean Louis 
Published: May 2005

AbstractWe have developed a new technique for the collection of DNA fragments separated by capillary electrophoresis, by direct transfer from the capillary outlet to a positively charged membrane. Transfer and post‐run detection of two different nonradioactivety labeled DNA standards, ranging in size from 150 bp to 2 kbp and 120 bp to 23 kbp are presented, and discussed. Capillary electrophoresis with direct blotting presents several advantages over the blotting from gels: the separation is faster and requires less manual steps, the resolution is higher, and each DNA fragment is collected into a very concentrated spot on the membrane due to the small surface of the capillary outlet and to a design of the collection device inducing a refocusing of field lines across the hybridization membrane. Therefore, very small amounts of DNA (in the pg range) can be detected. This fraction collection makes further analysis of the sample possible, e.g. by hybridization, thus suppressing one of the major present limitations of the capillary electrophoresis technique for DNA analysis In part presented at the international meeting Electrophoresis '95, Paris, France, August 30–September 2, 1995
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Some properties of a measure of resolution in gel electrophoresis and capillary zone electrophoresis
Authors: Weiss George H. , Kiefer James E. 
Published: May 2005

AbstractThe most commonly used measure of resolution for chromatographic and electrophoretic separations does not take into account the possibility of there being different amounts of each of the molecular species. A modification of a measure of resolution recently suggested by Aldroubi and Garner (BioTechniques 1992, 13, 620–624) can incorporate this effect explicitly. Their criterion for resolution is based on the time to observe a valley of specified magnitude separating two peaks. We examine how this measure depends on different physically relevant parameters that characterize the system.
Generation of peptide maps by capillary zone electrophoresis in isoelectric iminodiacetic acid
Authors: Bossi Alessandra , Righetti Pier Giorgio 
Published: May 2005

AbstractCapillary zone electrophoresis in stationary, isoelectric buffers is a novel method for generating peptide maps of protein digests. The buffer system developed is composed of iminodiacetic acid (IDA), whose physico‐chemical parameters were found – by theoretically modeling and experimental verification – to be: pI 2.23 (at 100 mM concentration), pK1 = 1.73 and pK2 = 2.73 (no attempts were made at measuring the pK of the primary amino group, since such a low pI value would be compatible with any pK value of the basic group, down to as low as pK 5.5). IDA is compatiable with most hydro‐organic solvents, including trifluoreoethanol (TFE), up to at least 40% v/v, typically used for modulating peptide mobility. In naked capillaries, a buffer comprising 50 mM IDA, 10% TFE and 0.5% hydroxyethylcellulose (HEC) allows generation of peptide maps with high resolution, reduced transit times and no interaction of even large peptides with the wall. However, the best background electrolyte was found to be a solution of 50 mM IDA in 0.5% HEC and 6–8 M urea, one of the best solubilizers of proteins and peptides known. In this last electrolyte system, peptide maps of β‐casein digests (known to contain also very large peptides, up to 6000 Da) could be generated with excellent resolution and half the transit times as compared with the standard buffer adopted in peptide analysis (80 mM phosphate buffer, pH 2.0). IDA thus appears to be another valid isoelectric buffer system, operating in a different pH window (pH 2.33 in 50 mM IDA) as compared to the other amphotere previously adopted (50 mM Asp, pH 2.77) for the same kind of analysis.
Detection of underivatized carbohydrates in capillary electrophoresis with a bienzyme electrode
Authors: Wei Hongping , Wang Tianlin , Li Sam F. Y. 
Published: May 2005

AbstractA new approach to detect underivatized carbohydrates in capillary zone electrophoresis (CZE) with a bienzyme electrode is described. The bienzyme electrode is based on immobilization of two enzymes, glucose oxidase and amyloglucosidase, on a platinum microelectrode. Maltose and glucose were used as substrates to establish the method and study its feasibility. Using this electrode, underivatized glucose and maltose were determined after separation in 60 mM borate buffer (pH 9.3) by CZE. A liquid junction, between the surface of the bienzyme electrode and the outlet of the separation capillary, was used to lower the pH of the eluting separation borate buffer so that the immobilized enzymes could maintain high activities. The detection limits were 0.17 mM for maltose and 0.35 mM for glucose. The effects of borate ion and pH on the responses of the bienzyme electrode to maltose and glucose are discussed. The bienzyme electrode did not show any decay in responses to maltose or glucose during one week of continuous operation.
Determination of the association constant for slow phosphoserine‐anti‐phosphoserine interaction kinetics by capillary zone electrophoresis
Authors: Lin Shiming , Hsu Su‐Ming 
Published: May 2005

AbstractCapillary zone electrophoresis (CZE) was used to study the interaction of a monoclonal anti‐phosphoserine antibody with its antigen. A model system that allows the determination of the real binding constant in a solution based on the change in peak areas at different concentrations of phosphoserine has been used for studying slow monoclonal antibody‐antigen interaction kinetics involving low‐molecular‐weight antigens. CZE was applied in preincubation experiments. The slow interaction kinetics led to band broadening and resulted in far lower efficiency of the separation of complexed antibody from unbound antibody. However, when the run‐to‐run reproducibility of free phosphoserine was examined, it was found that it can be recovered quantitatively under electrophoresis conditions. On the basis of measurement of peak areas at different phosphoserine concentrations, the association constant was estimated (Ka = 5.21 × 105 M−1) and shown to be in close agreement with that obtained by equilibrium dialysis (Ka = 4.65 × 105 M−1). As long as the antigen participating in the interaction can be detected and recovered quantiatively in the CZE system, the method is generally useful for the study of monoclonal antibody‐antigen interaction where the kinetics is slow and where the charge/mass ratio of the unbound antigen differs from that of the complexed molecule.
Detection and semiquantitation of albumin forms in fresh human plasma separated on gradient polyacrylamide gel by means of electroblotting on agarose gel matrix
Authors: Atmeh Ragheb F. , Shabsoug Barakat 
Published: May 2005

AbstractAlbumin in vitro contains several molecular forms, while in vivo it exists mainly as a monomer with a small fraction of a dimer. The aim of the present work was to detect and estimate albumin forms in fresh blood samples. The available analytical methods at present are inadequate for this purpose. An improved immunoblotting method was used where plasma was subjected to electroporetic separation on 4–25% gradient polyacrylamide gels followed by immunoblotting on agarose gel containing anti‐human albumin. The interference from the huge amount of the monomer in plasma was overcome by cutting the monomer region from the polyacrylamide gel before immunoblotting. After staining of the agarose gel, it revealed the presence of seven stained bands of albumin in addition to the monomer. These bands represent albumin aggregates and complexes of varying molecular masses (112–428 kDa). These albumin forms accounted for 0.7% of the total plasma albumin and their estimated level was 30.7 mg/dL. This study shows that the native albmin in blood has several molecular forms. It is concluded that albumin in healthy human subjects may form association complexes of varying molecular masses with other macromolecules in blood and these complexes are expected to be of physiological relevance.
Peak broadening in capillary zone electrophoresis
Authors: Gaš Bohuslav , Štědrý Milan , Kenndler Ernst 
Published: May 2005

AbstractA review on peak broadening in capillary zone electrophoresis in free solutions is given which covers a selection of the literature published on this topic over the period mainly between 1992 and the beginning of 1997 (consisting of 71 publications). The contributions to peak dispersion from extracolumn effects (e.g. due to the finite length of the injection zone, or the aperture of the detector), from longitudinal diffusion, Joule heating, electromigration dispersion (concentration overload), a different path length of the solute ions, wall adsorption, laminar flow and the (longitudinally) homogeneous or nonhomogeneous electroosmotic flow are described. The latter may also occur when a longitudinally nonhomogeneous radial electric field is applied. Peak dispersion is depicted either by the plate‐height model, or the concentration of the solute as a function of space and time is calculated either analytically or numerically by solving the equation of continuity with appropriate initial and boundary conditions and possibly completed by equations governing further quantities.
Recent application and developments of capillary isotachophoresis
Authors: Gebauer Petr , Boček Petr 
Published: May 2005

AbstractCapillary isotachophoresis is a powerful electromigration separation method with a pronounced capability to concentrate trace components in diluted samples. At present, capillary isotachophoresis is utilized predominantly as the first step in on‐line combination with capillary zone electrophoresis. This article is a continuation of previous reviews and summarizes the results published during 1993–1996.
Advances in capillary electrochromatography
Authors: Colón Luis A. , Reynolds Kimberly J. , Alicea‐Maldonado Rafael , Fermier Adam M. 
Published: May 2005

AbstractCapillary electrochromatography (CEC) is a hybrid between capillary electrophoresis and high performance liquid chromatography (HPLC) that has gained popularity in recent years. CEC uses an electrically driven flow to transport the solutes through the chromatographic column. Separation can be achieved by differential partition between two phases, differential electromigration, or a combination of these two. Herein, the main features of CEC are presented, including basic principles and a literature overview on different practical approaches used.
Capillary electrophoresis in presence of sodium dodecyl sulfate and a sieving medium
Authors: Takagi Toshio 
Published: May 2005

AbstractFor analysis of proteins in presence of sodium dodecyl sulfate (SDS), basic knowledge about their behavior in presence and absence of sieving medium is required. Capillary electrophoresis (CE) is particularly suitable for this purpose. Although various polymers are used as sieves in CE analysis in presence of SDS, attention must be paid to possible interaction between SDS and the polymer. For obtaining new insights polymers with defined molecular weight and distribution should be utilized.
Recent advances in capillary electrophoresis/electrospray/mass spectrometry
Authors: Banks J. Fred 
Published: May 2005

AbstractSuccessful on‐line interfacing of capillary electrophoresis (CE) with electrospray (ES) mass spectrometry (MS) has progressed substantially in recent years. Of particular note also is the development which has occurred in combining the more advanced capillary‐based electromigration separation techniques, such as capillary gel electrophoresis (CGE), capillary isoelectric focusing (CIEF), capillary isotachophoresis (CIT), micellar electrokinetic chromatography (MEKC) and capillary electrochromatography (CEC), with ES/MS. The union of these electromigration schemes with MS detection provides a useful and sensitive analytical tool for the separation, quantitation and identification of biological, therapeutic, environmental and other important classes of chemical analytes. By making optimal use of the characteristics inherent with these separation mechanisms, greatly enhanced MS performance may be obtained. The following review summarizes the significant issues and challenges involved with CE/ES/MS analysis as well as results which have recently been obtained.
Electrochemical detection in capillary electrophoresis
Authors: Voegel Phillip D. , Baldwin Richard P. 
Published: May 2005

AbstractRecent advances in the design and application of electrochemical detection (EC) systems in capillary electrophoresis (CE) are reviewed, with the objective of providing the non‐electrochemist with a state‐of‐the‐art picture of CEEC instrumentation and an overview of the primary analytes and samples for which the technique is best suited. In particular, instrument innovations designed to aid in decoupling the CE and EC systems electrically and in aligning them physically are described in detail. In addition, CEEC applications are summarized for four specific analyte groups: catecholamines, thiols and disulfides, amino acids, and carbohydrates. On this basis, it is clear that EC techniques have reached a stage where they are already having a significant impact on CE usage in selected areas of analysis. Continued developments with respect to new electrode materials and electrode configurations promise to broaden this impact further.
Critical review of recent developments in fluorescence detection for capillary electrophoresis
Authors: MacTaylor Christine E. , Ewing Andrew G. 
Published: May 2005

AbstractRecent developments in capillary electrophoresis with fluorescence detection are reviewed. Instrumental advances have led to increased sensitivity and, therefore, a growing number of applications. Capillary electrophoresis has been coupled with various techniques to achieve multi‐dimensional separations. Other advances have focused on temporal resolution when sampling from biological environments, increased sample throughput especially for DNA analysis, and fast separation times. New technologies including chip and channel electrophoretic separations with fluorescence detection are also discussed.
Chiral separations in capillary electrophoresis using proteins as stereoselective binding agents
Authors: Hage David S. 
Published: May 2005

AbstractProteins are receiving increased attention in capillary electrophoresis (CE) for use as ligands in chiral separations. This review examines the types of proteins that have been employed in CE for the analysis of chiral compounds and provides a summary of applications for such an approach. Several formats for this type of analysis are discussed, including methods that use immobilized proteins (i.e., affinity capillary electrochromatography and capillary gel affinity electrophoresis) or techniques that use proteins as running buffer additives (i.e., affinity capillary electrophoresis). The role of various experimental factors in these separations are considered, and a comparison is made between the general analytical properties of CE systems that use immobilized versus solution‐phase proteins.
Chiral surfactants in micellar electrokinetic capillary chromatography
Authors: Camilleri Patrick 
Published: May 2005

AbstractMost biologically active molecules contain one or more chiral centres, giving rise to stereoisomeric forms which can behave differently in a chiral environment. Thus, only one of the enantiomers may show the desired physiological activity, whereas the other enantiomers may either be considerably less active or even show undesireable side effects. Establishing that a chiral drug consists of one single enantiomer is nowadays essential before it can be given to patients. Analytical tools that can discriminate between enantiomers play a very important role in determining the stereoisomeric composition of chiral molecules. Until recently chromatographic techniques were the most popular for enantiomeric separations. The increased use of capillary electrophoresis (CE) has provided complementary methodology for chiral discrimination. One mode of CE that has been used for this purpose is micellar electrokinetic capillary chromatography (MECC), where natural or synthetic chiral surfactants are added to the separation buffer.