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Kartsova LA, Kravchenko AV, Kolobova EA. Covalent Coatings of Quartz Capillaries for the Electrophoretic Determination of Biologically Active Analytes. JOURNAL OF ANALYTICAL CHEMISTRY 2019. [DOI: 10.1134/s1061934819080100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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2
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Beneito-Cambra M, Anres P, Vial J, Gareil P, Delaunay N. Stability and effectiveness of linear polyacrylamide capillary coating to suppress EOF in acidic media in the presence of surfactants, ionic liquids and organic modifiers. Talanta 2016; 150:546-52. [DOI: 10.1016/j.talanta.2015.12.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/22/2015] [Accepted: 12/26/2015] [Indexed: 11/25/2022]
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3
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Al-Ghobashy MA. Electrophoretic behavior of charge regulated zwitter ionic buffers in covalently and dynamically coated fused silica capillaries. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.bfopcu.2014.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Photopolymerization of acrylamide as a new functionalization way of silica monoliths for hydrophilic interaction chromatography and coated silica capillaries for capillary electrophoresis. J Chromatogr A 2014; 1326:89-95. [DOI: 10.1016/j.chroma.2013.12.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 11/21/2022]
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5
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Potential of polyE-323 coated capillaries for capillary electrophoresis of lipids. J Chromatogr A 2013; 1317:193-8. [DOI: 10.1016/j.chroma.2013.08.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 08/14/2013] [Accepted: 08/14/2013] [Indexed: 01/05/2023]
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6
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Dziubakiewicz E, Buszewski B. Principles of Electromigration Techniques. SPRINGER SERIES IN CHEMICAL PHYSICS 2013. [DOI: 10.1007/978-3-642-35043-6_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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7
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Chu Y, Xu W, Edgar JS, Shou C. Synthesis of hyperbranched polycarbosilane modified with cyclodextrin derivatives and its application in coated capillary electrophoresis columns. J Appl Polym Sci 2011. [DOI: 10.1002/app.34273] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Elsherbiny AS, Egelhaaf HJ, Oelkrug D. Accessibility and shielding of silanol surface centers on porous silica beads; UV/vis absorption and fluorescence studies. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Bayer E, Jennings WG, Majors RE, Kirkland JJ, Unger KK, Engelhardt H, Schomburg G, Pirkle WH, Welch CJ, Armstrong DW, Porath JO, Sjövall JB, Gehrke CW. History and Developments in Chromatographic Column Technology and Validation to 2001. CHROMATOGRAPHY 2010. [DOI: 10.1002/9780470555729.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Phinney KW, Sander LC. Dynamically coated capillaries for enantioselective separations by capillary electrophoresis. Chirality 2005; 17 Suppl:S65-9. [PMID: 15765536 DOI: 10.1002/chir.20121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The level of variability in migration times and peak areas often encountered in capillary electrophoresis (CE) has restricted its use for routine analysis. Cationic analytes also tend to interact with the capillary wall, resulting in skewed peak shapes and reduced efficiency. We investigated a dynamic coating procedure that involves a two-step process to modify the capillary and that results in a higher but stable electro-osmotic flow (EOF) at low pH. We compared enantioselective separations of several basic compounds on unmodified and dynamically coated capillaries. A derivatized cyclodextrin was used as the chiral additive. When the dynamic coating was used, peak symmetry improved, and migration times were significantly shorter. The dynamic coating procedure also resulted in improved migration time and peak area precision.
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Affiliation(s)
- Karen W Phinney
- Analytical Chemistry Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8392, USA.
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11
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Heinemann U, Blaschke G, Knebel N. Simultaneous enantioselective separation of azelastine and three of its metabolites for the investigation of the enantiomeric metabolism in rats. I. Liquid chromatography-ionspray tandem mass spectrometry and electrokinetic capillary chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 793:389-404. [PMID: 12906914 DOI: 10.1016/s1570-0232(03)00357-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Enantioselective separation methods and the enantioselective determination of the anti-allergic drug azelastine and of three of its main phase I metabolites in a biological matrix underwent chromatographic and electrophoretic investigations. An enantioselective assay of a coupling of HPLC using a beta-cyclodextrin chiral stationary phase to ionspray tandem mass spectrometry is presented. Additionally, this assay is compared to another enantioselective assay using electrokinetic capillary chromatography with beta-cyclodextrin and carboxymethyl-beta-cyclodextrin in polyacrylamide-coated capillaries. For capillary electrophoresis (CE) the importance of polyacrylamide coating for the validation of this separation method is highlighted. Extracted rat plasma samples of enantioselective metabolism studies were measured by both validated assays. Differences in the pharmacokinetics and pharmacodynamics were evaluated for the main substance azelastine and its main metabolite demethylazelastine. So, a first hint about the enantioselectivity of biotransformation of azelastine in rats was seen after oral application of either enantiomer or the racemate to rats.
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Affiliation(s)
- Ute Heinemann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster Hittorfstrasse 58-62, D-48149 Münster, Germany
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12
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Abstract
There is a great deal of interest in continuous beds as stationary phases for both HPLC and CEC. There are various ways to prepare monoliths, by polymerization of organic species or by polymerization of silicon alkoxides. The former method has recently been reviewed, while silica based monoliths are now commercially available. The purpose of this paper is to deal with the problems associated with silica based monoliths. The most important problem is obviously the cracking and the shrinkage of the bed during drying. The second problem is monolith cladding. Much literature has been published but no definitive solution is available and thus a wide research area remains open. Monoliths are a compromise between loadability, permeability and mass transfer kinetics. Due to the better mass transfer properties of a monolithic skeleton over distinct particles, high flow rates and high speed separations are possible.
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Affiliation(s)
- A M Siouffi
- UMR 6516, Université d'Aix Marseille, France.
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13
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Hsieh YY, Lin YH, Yang JS, Wei GT, Tien P, Chau LK. Electroosmotic flow controllable coating on a capillary surface by a sol-gel process for capillary electrophoresis. J Chromatogr A 2002; 952:255-66. [PMID: 12064537 DOI: 10.1016/s0021-9673(02)00079-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A simple coating procedure employing a sol-gel process to modify the inner surface of a bare fused-silica capillary with a positively charged quaternary ammonium group is established. Scanning electron microscopic studies reveal that a smooth coating with 1 to approximately 2 microm thickness can be obtained at optimized coating conditions. With 40 mM citrate as a running electrolyte, the plot of electroosmotic flow (EOF) versus pH shows a unique three-stage EOF pattern from negative to zero and then to positive over a pH range of 2.5 to 7.0. At pH above 5.5, the direction of the EOF is from the anode to the cathode, as is the case in a bare fused-silica capillary, and the electroosmotic mobility increases as the pH increases. However, the direction of the EOF is reversed at pH below 4.0. Over the pH range of 4.0 to 5.5, zero electroosmotic mobility is obtained. Such a three-stage EOF pattern has been used to separate six aromatic acids under suppressed EOF and to separate nitrate and nitrite with the anions migrating in the same direction as the EOF. The positively charged quaternary ammonium group on the coating was also utilized to minimize the adsorption problem during the separation of five basic drugs under suppressed EOF and during the separation of four basic proteins with the cations migrate in the opposite direction as the EOF. Also, the stability and reproducibility of this column are good.
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Affiliation(s)
- Yi-Yun Hsieh
- Department of Chemistry, National Chung Cheng University, Ming-Hsiung, Chia-Yi, Taiwan
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14
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Bohrisch J, Schimmel T, Engelhardt H, Jaeger W. Charge Interaction of Synthetic Polycarboxybetaines in Bulk and Solution. Macromolecules 2002. [DOI: 10.1021/ma0122019] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jörg Bohrisch
- Fraunhofer-Institut für Angewandte Polymerforschung, D-14476 Golm, Germany, and Saarland University, Instrumental and Environmental Analysis, Im Stadtwald, D-66123 Saarbrücken, Germany
| | - Thomas Schimmel
- Fraunhofer-Institut für Angewandte Polymerforschung, D-14476 Golm, Germany, and Saarland University, Instrumental and Environmental Analysis, Im Stadtwald, D-66123 Saarbrücken, Germany
| | - Heinz Engelhardt
- Fraunhofer-Institut für Angewandte Polymerforschung, D-14476 Golm, Germany, and Saarland University, Instrumental and Environmental Analysis, Im Stadtwald, D-66123 Saarbrücken, Germany
| | - Werner Jaeger
- Fraunhofer-Institut für Angewandte Polymerforschung, D-14476 Golm, Germany, and Saarland University, Instrumental and Environmental Analysis, Im Stadtwald, D-66123 Saarbrücken, Germany
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15
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Strelec I, Pacáková V, Bosáková Z, Coufal P, Guryca V, Stulík K. Modification of capillary electrophoresis capillaries by poly(hydroxyethyl methacrylate), poly(diethylene glycol monomethacrylate) and poly(triethylene glycol monomethacrylate). Electrophoresis 2002; 23:528-35. [PMID: 11870760 DOI: 10.1002/1522-2683(200202)23:4<528::aid-elps528>3.0.co;2-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Modification of capillary electrophoresis (CE) capillaries by poly(hydroxyethyl methacrylate) (poly(HEMA), poly(diethylene glycol monomethacrylate) (poly(DEGMA) and poly(triethylene glycol monomethacrylate) (poly(TEGMA), was studied. Methods based on physical adsorption of the modifier and on its chemical binding were compared on the basis of the electroosmotic flow (EOF) reproducibility, the EOF dependence on the pH, the symmetry of the peak of positively charged tyramine, the stability of the coating and the separation of standard and milk proteins in the modified capillaries. Reproducible coatings were obtained by chemical binding of the polymers to the capillary walls and by coating with a solution of a polymer, as also demonstrated by the atomic force microscopy.
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Affiliation(s)
- Ivo Strelec
- Charles University, Department of Analytical Chemistry, Prague, Czech Republic
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16
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Tran NT, Cabanes-Macheteau M, Taverna M. Chapter 20 Analysis of glycoproteins and their glycopeptide and glycan fragments by electrophoresis and capillary electrophoresis. JOURNAL OF CHROMATOGRAPHY LIBRARY 2002. [DOI: 10.1016/s0301-4770(02)80045-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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17
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Wan H, Ohman M, Blomberg LG. Bonded dimethylacrylamide as a permanent coating for capillary electrophoresis. J Chromatogr A 2001; 924:59-70. [PMID: 11521909 DOI: 10.1016/s0021-9673(01)00715-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A method for coating capillaries for capillary electrophoresis with chemically bonded polydimethylacrylamide has been developed, and the properties of the capillaries have been evaluated. The coated capillaries provided high separation efficiency, 12 x 10(5) theoretical plates/m was obtained for cytochrome c. The electroosmotic flow at pH 8.0 was 10 x 10(-10) to 6 x 10(-10) m2 V(-1) s(-1). The coated capillaries were quite stable at high pH. At least 150 runs could be done at pH 10 without appreciable performance deterioration. The excellent performance of the coated capillaries was illustrated by separation of basic proteins, acidic proteins, 9-fluorenylmethyl chloroformate-derivatized neurotransmitter amino acids, peptide reference mixtures and peptides digested from a bacteria protein.
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Affiliation(s)
- H Wan
- Department of Chemistry, Karlsrad University, Sweden
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18
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Abstract
This review article describes the preparation of dynamic and static polymeric wall coatings for capillary electrophoresis. Properties of bare fused-silica surfaces and methods for the characterization of capillary coatings are summarized. The preparation and basic properties of neutral and charged wall coatings are considered. Finally, advantages and potential applications of various coatings are discussed.
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Affiliation(s)
- J Horvath
- Molecular Dynamics Inc., Sunnyvale, CA 94085, USA.
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19
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Molecular weight analysis of polycations by capillary electrophoresis in a solution of neutral polymers. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00908-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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21
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König S, Welsch T. Moderation of the electroosmotic flow in capillary electrophoresis by chemical modification of the capillary surface with tentacle-like oligourethanes. J Chromatogr A 2000; 894:79-88. [PMID: 11100850 DOI: 10.1016/s0021-9673(00)00718-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The surface chemistry of the inner wall of fused-silica capillaries is one important means to control the magnitude as well as the direction of the electroosmotic flow and the adsorption activity. A method was developed to change the surface characteristics of fused-silica capillaries by binding tentacle-like oligourethane groups onto the inner surface. The electroosmotic flow at a buffer pH of 6-9 was reduced by 15 to 40% compared to that in a bare fused-silica tubing, dependent on the type of coating. Sample adsorption is diminished at the same time resulting in a separation of proteins with higher resolution and good migration time precision. At a pH below 4.5 the electroosmotic flow is reversed into the anodic direction, which offers further possibilities for the separation of positively charged analytes as demonstrated for the separation of aromatic and biogenic amines.
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Affiliation(s)
- S König
- Department of Analytical and Environmental Chemistry, University of Ulm, Germany
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22
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Grosche O, Bohrisch J, Wendler U, Jaeger W, Engelhardt H. Characterization of synthetic polyelectrolytes by capillary electrophoresis. J Chromatogr A 2000; 894:105-16. [PMID: 11100853 DOI: 10.1016/s0021-9673(00)00774-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Capillary electrophoresis in entangled polymer solutions was applied to determine the molecular mass and polydispersity of polyelectrolytes. The separation selectivities of different polyethylene glycols as buffer additive can be correlated to their average molecular mass. A universal curve correlating the selectivity and the molecular mass could be obtained by using the instrinsic viscosity of the polyethylene glycol. The separation of poly(2-vinylpyridine) standards was compared to the separation of poly(4-vinylpyridine) standards. An indirect detection system was developed to characterize the cationic polyelectrolyte polydiallyldimethyl ammonium chloride. Various polymers with oppositely charged groups (polycarboxybetaines) were investigated with respect to structure dependence, pH dependence and molecular mass dependence of interand intramolecular association.
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Affiliation(s)
- O Grosche
- University of the Saarland, Instrumental and Environmental Analysis, Saarbrücken, Germany
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23
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24
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Russo MV, Goretti G. Hydrophobic-phase-modified fused-silica columns for capillary electrophoresis. J Chromatogr A 2000; 871:279-87. [PMID: 10735308 DOI: 10.1016/s0021-9673(99)01241-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Coated capillaries modified with a hydrophobic layer were developed. Linear hydrocarbons and ethylbenzene modified surfaces greatly improved the electrophoretic performance of the capillaries. The column efficiency for organic compounds reached as high as 327 000 theoretical plate numbers per meter on a 50 microm I.D. linear hydrocarbon (C6) surface treated fused-silica capillary column. This value did not change during 50 repeated analyses and the columns showed strong stability against 0.1 M NaOH and 0.1 M HCl. The relative standard deviation of the run-to-run, day-to-day, and capillary-to-capillary coating with hydrophobic layer showed values of < or =2.5%, and good reproducibility. The separations of four aromatic amines and six pharmacological amines at pH 2.5 is reported.
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Affiliation(s)
- M V Russo
- Università del Molise, Facoltà di Agraria (DiSTAAM), Campobasso, Italy.
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25
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Capillaries and the Electroosmotic Flow. CAPILLARY ELECTROPHORESIS: INSTRUMENTATION AND OPERATION 2000. [DOI: 10.1007/978-3-322-83133-0_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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26
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Rodriguez I, Li S. Surface deactivation in protein and peptide analysis by capillary electrophoresis. Anal Chim Acta 1999. [DOI: 10.1016/s0003-2670(98)00485-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Pantazaki A, Taverna M, Vidal-Madjar C. Recent advances in the capillary electrophoresis of recombinant glycoproteins. Anal Chim Acta 1999. [DOI: 10.1016/s0003-2670(98)00495-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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29
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Bibeau DR, Smith KB, Smith EM, Ewing AG. Separations of DNA fragments with a coated 25-?m capillary coupled to a 25-?m high open channel. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1520-667x(1999)11:8<567::aid-mcs1>3.0.co;2-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Cifuentes A, Canalejas P, Ortega A, Dı́ez-Masa JC. Treatments of fused-silica capillaries and their influence on the electrophoretic characteristics of these columns before and after coating. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00295-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Finkler C, Charrel H, Engelhardt H. Permanent coated capillaries with reversed electroosmotic flow for anion analysis. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00603-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Huang X, Doneski LJ, Wirth MJ. Surface-Confined Living Radical Polymerization for Coatings in Capillary Electrophoresis. Anal Chem 1998; 70:4023-9. [DOI: 10.1021/ac980231c] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xueying Huang
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Leon J. Doneski
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Mary J. Wirth
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716
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33
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Clos HN, Engelhardt H. Separations of anionic and cationic synthetic polyelectrolytes by capillary gel electrophoresis. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(97)01077-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Abstract
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.
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Affiliation(s)
- V Dolnik
- Molecular Dynamics, Sunnyvale, CA 94086, USA.
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35
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Hayes JD, Malik A. Sol-gel chemistry-based Ucon-coated columns for capillary electrophoresis. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1997; 695:3-13. [PMID: 9271124 DOI: 10.1016/s0378-4347(97)00134-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A sol-gel chemistry-based novel approach for the preparation of a Ucon-coated fused-silica capillary column in capillary electrophoresis is presented. In this approach the sol-gel process is carried out inside 25 microm I.D. fused-silica capillaries. The sol solution contained appropriate quantities of an alkoxide-based sol-gel precursor, a polymeric coating material (Ucon), a crosslinking reagent, a surface derivatizing reagent, controlled amounts of water and a catalyst dissolved in a suitable solvent system. The coating procedure involves filling a capillary with the sol solution and allowing the sol-gel process to proceed for an optimum period. Hydrolysis of the alkoxide precursor and polycondensation of the hydrolyzed products with the surface silanol groups and the hydroxy-terminated Ucon molecules lead to the formation of a surface-bonded sol-gel coating on the inner walls of the capillary. The thickness of the coated film can be controlled by varying the reaction time, coating solution composition and experimental conditions. Commercial availability of high purity sol-gel precursors (e.g., TEOS 99.999%), the ease of coating, run-to-run and column-to-column reproducibility, and long column lifetimes make sol-gel coating chemistry very much suitable for being applied in analytical microseparations column technology. Test samples of basic proteins and nucleotides were used to evaluate the column performance. These results show that the sol-gel coating scheme has allowed for the generation of bio-compatible surfaces characterized by high separation efficiencies in CE. For different types of solutes, the sol-gel coated Ucon column consistently provided migration time R.S.D. values of the order of 0.5%.
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Affiliation(s)
- J D Hayes
- Department of Chemistry, University of South Florida, Tampa 33620-5250, USA
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36
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Janini GM, Muschik GM, Issaq HJ. Micellar electrokinetic chromatography in zero-electroosmotic flow environment. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1996; 683:29-35. [PMID: 8876436 DOI: 10.1016/0378-4347(96)00130-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Micellar electrokinetic chromatography (MEKC) is conducted in polyacrylamide-coated capillaries under almost complete suppression of electroosmotic flow. The equations of migration and resolution for neutral solutes in this mode of MEKC operation are presented. The technique is termed reversed-flow MEKC (RF-MEKC) because, in contrast to MEKC in bare-silica capillaries (N-MEKC), solute migration order is reversed and solute migration time is inversely proportional to micelle concentration. This presents an advantage for the high-efficiency separation of extremely and moderately hydrophobic solutes in a short analysis time. Examples of the separation of polycyclic aromatic hydrocarbons, aflatoxins and dansylated-amino acids are presented using sodium dodecyl sulfate (SDS) surfactant. Polycyclic aromatic hydrocarbons are separated using a relatively low micelle concentration. The detection sensitivity for these compounds is enhanced in two ways. First, the peaks are sharp because of the short analysis time and the inertness of the column surface. Second, the fluorescence background and Joule's heating are minimal because of the low concentration of SDS and other additives needed to affect the separation. While N-MEKC is mainly conducted with basic buffers, RF-MEKC can be conducted in basic as well as acidic media as illustrated in the separation of 15 dansylated-amino acids at pH 4.2.
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Affiliation(s)
- G M Janini
- SAIC Frederick, NCI-Frederick Cancer Research and Development Center, MD 21702, USA
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37
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Use of plate numbers achieved in capillary electrophoretic protein separations for characterization of capillary coatings. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(95)00485-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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