The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Ziad El Rassi - One of the best experts on this subject based on the ideXlab platform.
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Enzymophoresis of nucleic acids by tandem Capillary enzyme reactor-Capillary Zone electrophoresis
Journal of chromatography, 1992Co-Authors: Wassim Nashabeh, Ziad El RassiAbstract:Enzymophoresis with coupled heterogeneous Capillary enzyme reactor-Capillary Zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in Capillary Zone electrophoresis. The Capillary enzyme reactors coupled in series with Capillary Zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantitatives of oligonucleotides.
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enzymophoresis of nucleic acids by tandem Capillary enzyme reactor Capillary Zone electrophoresis
Journal of Chromatography A, 1992Co-Authors: Wassim Nashabeh, Ziad El RassiAbstract:Enzymophoresis with coupled heterogeneous Capillary enzyme reactor-Capillary Zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in Capillary Zone electrophoresis. The Capillary enzyme reactors coupled in series with Capillary Zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantitatives of oligonucleotides.
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On-Line Preconcentration of Triazine Herbicides with Tandem Octadecyl Capillaries - Capillary Zone Electrophoresis
Journal of Liquid Chromatography, 1992Co-Authors: Jianyi Cai, Ziad El RassiAbstract:Abstract Fused-silica capillaries having surface-bound octadecyl functions were developed for on-line preconcentration of dilute samples prior to Capillary Zone electrophoresis. The performance of tandem octadecyl capillaries-Capillary Zone electrophoresis was evaluated with solutes of environmental significance, e.g., prorheton and prornetryne. The on-line preconcentration was best achieved when oligomeric octadecyl capillaries having roughened inner walls were employed. The coupled configuration enhanced the detectability in terms of solute concentration by a factor of 10 to 35 as compared to that obtained by Capillary Zone electrophoresis alone. Large volumes of samples could be introduced without affecting separation efficiency.
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Determination of the ionization constants of weak electrolytes by Capillary Zone electrophoresis
Journal of High Resolution Chromatography, 1992Co-Authors: Jianyi Cai, Joel T. Smith, Ziad El RassiAbstract:Capillary Zone electrophoresis in untreated fused silica capillaries has proved suitable for the determination of the ionization constants of weak electrolytes. Several fundamental equations relating the electrophoretic mobilities of ionized solutes to hydronium ion concentrations in the running electrolyte have been verified experimentally. The observed dependence of the electrophoretic mobilities of weak bases and ampholytes on the pH of the electrolyte showed good agreement with predicted behavior. The pKa values calculated from electrophoretic mobility data obtained by Capillary Zone electrophoresis were reasonably close to those reported in the literature.
Wassim Nashabeh - One of the best experts on this subject based on the ideXlab platform.
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enzymophoresis of nucleic acids by tandem Capillary enzyme reactor Capillary Zone electrophoresis
Journal of Chromatography A, 1992Co-Authors: Wassim Nashabeh, Ziad El RassiAbstract:Enzymophoresis with coupled heterogeneous Capillary enzyme reactor-Capillary Zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in Capillary Zone electrophoresis. The Capillary enzyme reactors coupled in series with Capillary Zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantitatives of oligonucleotides.
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Enzymophoresis of nucleic acids by tandem Capillary enzyme reactor-Capillary Zone electrophoresis
Journal of chromatography, 1992Co-Authors: Wassim Nashabeh, Ziad El RassiAbstract:Enzymophoresis with coupled heterogeneous Capillary enzyme reactor-Capillary Zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in Capillary Zone electrophoresis. The Capillary enzyme reactors coupled in series with Capillary Zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantitatives of oligonucleotides.
Salvatore Fanali - One of the best experts on this subject based on the ideXlab platform.
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Capillary Zone electrophoresis separations of enantiomers present in complex ionic matrices with on-line isotachophoretic sample pretreatment.
Journal of Chromatography A, 1999Co-Authors: M Danková, Salvatore Fanali, D Kaniansky, F IványiAbstract:Abstract Analytical capabilities of Capillary Zone electrophoresis (CZE) with on-line coupled Capillary isotachophoresis (ITP) sample pretreatment in the column-coupling Capillary electrophoresis equipment to separate and determine enantiomers present in multicomponent ionic matrices were studied. Tryptophan was used as a model analyte in the ITP-Capillary Zone electrophoresis experiments performed in this context while a 90-component model mixture of UV-light absorbing organic anions and urine served as multicomponent sample matrices. Various working modes in which the on-line coupled Capillary isotachophoresis–Capillary Zone electrophoresis combination in the column-coupling separation system can operate were employed in the anionic regime of the separation with direct injections of the samples. Advantages and limitations of these working modes in the separations of enantiomers present in model and urine matrices were assessed. Experiments with model mixtures of tryptophan enantiomers revealed that the two were resolved in the Capillary Zone electrophoresis stage with the aid of α-cyclodextrin also when their concentration ratio in the sample was 1:200 while the concentration of L (−)-tryptophan was 25 nmol/l. The limits of detection for the enantiomers were at ∼10 nmol/l (∼1.5 ng/ml) concentrations for a 220 nm detection wavelength of the UV detector employed in the Capillary Zone electrophoresis stage and for a 30 μl sample load. A high sample load capacity of the on-line coupled Capillary isotachophoresis stage was effective in separating the samples corresponding to 3–6 μl volumes of undiluted urine. The results from the runs with urine samples showed that only the Capillary isotachophoresis–Capillary Zone electrophoresis combination with a post-column on-line coupled Capillary isotachophoresis sample clean-up (responsible for a removal of more than 99% of the sample anionic constituents migrating in the on-line coupled Capillary isotachophoresis stack and detectable in the Capillary Zone electrophoresis stage) provided a universal alternative for the detection and quantitation of the model analyte ( L (−)-tryptophan).
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Separation of leucinostatins by Capillary Zone electrophoresis
Journal of Chromatography A, 1992Co-Authors: Maria Giovanna Quaglia, Salvatore Fanali, Annalisa Nardi, Carlo Rossi, Maurizio RicciAbstract:Abstract A Capillary Zone electrophoretic method was used to separate some leucinostatins, the nonapeptides obtained by submerged cultures of Paecilomyces marquandii or Paecilomyces lilacinus . These compounds are of pharmaceutical interest for their remarkable antibiotic, cytotoxic and phytotoxic activities. The proposed method allows the separation of leucinostatins from very complex mixtures and shows high efficiency, good resolution and a very short analysis time.
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Capillary Zone electrophoresis and mass spectrometry for the characterization of genetic variants of human hemoglobin
Analytical Biochemistry, 1991Co-Authors: Pasquale Ferranti, Salvatore Fanali, Annalisa Nardi, Antonio Malorni, Pietro Pucci, L. OssiciniAbstract:Abstract This paper describes a simple and rapid analytical method for the structural identification of abnormal human hemoglobins. Globin chains obtained by precipitation of erythrocyte hemolysate in cold acetone are directly analyzed by Capillary Zone electrophoresis in coated capillaries without any prior treatment. The speed and the high resolving power of Capillary Zone electrophoresis allow fast differentiation of hemoglobins with similar charges. Capillary Zone electrophoretic tryptic mapping has also been performed for each globin, so that complete variant characterization can be achieved by direct comparison of the variant tryptic map with the corresponding normal one. Coupling electrophoretic data with analysis of enzymatic digests by mass spectrometry according to the “fast atom bombardment mapping” procedure makes it possible to quickly identify amino acid variations. This paper describes how the method can be applied to the characterization of common and uncommon variants and underlines the advantages and limitations of the procedure along with its potential uses in structural analysis of proteins.
F Iványi - One of the best experts on this subject based on the ideXlab platform.
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Capillary Zone electrophoresis separations of enantiomers present in complex ionic matrices with on-line isotachophoretic sample pretreatment.
Journal of chromatography. A, 1999Co-Authors: M Danková, D Kaniansky, S Fanali, F IványiAbstract:Analytical capabilities of Capillary Zone electrophoresis (CZE) with on-line coupled Capillary isotachophoresis (ITP) sample pretreatment in the column-coupling Capillary electrophoresis equipment to separate and determine enantiomers present in multicomponent ionic matrices were studied. Tryptophan was used as a model analyte in the ITP-Capillary Zone electrophoresis experiments performed in this context while a 90-component model mixture of UV-light absorbing organic anions and urine served as multicomponent sample matrices. Various working modes in which the on-line coupled Capillary isotachophoresis-Capillary Zone electrophoresis combination in the column-coupling separation system can operate were employed in the anionic regime of the separation with direct injections of the samples. Advantages and limitations of these working modes in the separations of enantiomers present in model and urine matrices were assessed. Experiments with model mixtures of tryptophan enantiomers revealed that the two were resolved in the Capillary Zone electrophoresis stage with the aid of alpha-cyclodextrin also when their concentration ratio in the sample was 1:200 while the concentration of L(-)-tryptophan was 25 nmol/l. The limits of detection for the enantiomers were at approximately 10 nmol/l (approximately 1.5 ng/ml) concentrations for a 220 nm detection wavelength of the UV detector employed in the Capillary Zone electrophoresis stage and for a 30 microliters sample load. A high sample load capacity of the on-line coupled Capillary isotachophoresis stage was effective in separating the samples corresponding to 3-6 microliters volumes of undiluted urine. The results from the runs with urine samples showed that only the Capillary isotachophoresis-Capillary Zone electrophoresis combination with a post-column on-line coupled Capillary isotachophoresis sample clean-up (responsible for a removal of more than 99% of the sample anionic constituents migrating in the on-line coupled Capillary isotachophoresis stack and detectable in the Capillary Zone electrophoresis stage) provided a universal alternative for the detection and quantitation of the model analyte (L(-)-tryptophan).
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Capillary Zone electrophoresis separations of enantiomers present in complex ionic matrices with on-line isotachophoretic sample pretreatment.
Journal of Chromatography A, 1999Co-Authors: M Danková, Salvatore Fanali, D Kaniansky, F IványiAbstract:Abstract Analytical capabilities of Capillary Zone electrophoresis (CZE) with on-line coupled Capillary isotachophoresis (ITP) sample pretreatment in the column-coupling Capillary electrophoresis equipment to separate and determine enantiomers present in multicomponent ionic matrices were studied. Tryptophan was used as a model analyte in the ITP-Capillary Zone electrophoresis experiments performed in this context while a 90-component model mixture of UV-light absorbing organic anions and urine served as multicomponent sample matrices. Various working modes in which the on-line coupled Capillary isotachophoresis–Capillary Zone electrophoresis combination in the column-coupling separation system can operate were employed in the anionic regime of the separation with direct injections of the samples. Advantages and limitations of these working modes in the separations of enantiomers present in model and urine matrices were assessed. Experiments with model mixtures of tryptophan enantiomers revealed that the two were resolved in the Capillary Zone electrophoresis stage with the aid of α-cyclodextrin also when their concentration ratio in the sample was 1:200 while the concentration of L (−)-tryptophan was 25 nmol/l. The limits of detection for the enantiomers were at ∼10 nmol/l (∼1.5 ng/ml) concentrations for a 220 nm detection wavelength of the UV detector employed in the Capillary Zone electrophoresis stage and for a 30 μl sample load. A high sample load capacity of the on-line coupled Capillary isotachophoresis stage was effective in separating the samples corresponding to 3–6 μl volumes of undiluted urine. The results from the runs with urine samples showed that only the Capillary isotachophoresis–Capillary Zone electrophoresis combination with a post-column on-line coupled Capillary isotachophoresis sample clean-up (responsible for a removal of more than 99% of the sample anionic constituents migrating in the on-line coupled Capillary isotachophoresis stack and detectable in the Capillary Zone electrophoresis stage) provided a universal alternative for the detection and quantitation of the model analyte ( L (−)-tryptophan).
Vladislav Dolník - One of the best experts on this subject based on the ideXlab platform.
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Recent developments in Capillary Zone electrophoresis of proteins.
Electrophoresis, 1999Co-Authors: Vladislav DolníkAbstract:This review article with 125 references describes recent developments in Capillary Zone electrophoresis of proteins. It encompasses approximately the last two years, from the previous review (V. Dolnik,Electrophoresis 1997, 18, 2353—2361) through Spring 1999. Topics covered include modeling of the electrophoretic properties of proteins, sample preconcentration and derivatization, wall coatings, improving selectivity, special detection techniques, and applications.
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Capillary Zone electrophoresis of proteins
Electrophoresis, 1997Co-Authors: Vladislav DolníkAbstract:This review article with 237 references is focused on Capillary Zone electrophoresis (CZE) of proteins. It includes discussion of modeling electrophoretic migration of proteins, sample pretreatment before the analysis, methods reducing the sorptions of proteins on the Capillary wall, and techniques for increasing selectivity by using electrolyte additives including the sieving matrices. Significant progress in detection techniques, namely in laser-induced fluorescence and mass spectrometry, is emphasized. Modifications of CZE using specific interactions, such as affinity Capillary electrophoresis or Capillary immunoelectrophoresis, are debated as well as combination of CZE with other separation methods such as high performance liquid chromatography (HPLC). A number of practical applications of CZE of proteins are described.
