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Hendrickx A, De Klerck K, Mangelings D, Clincke L, Heyden YV. Three versus five micrometer chlorinated polysaccharide-based packings in chiral capillary electrochromatography: performance evaluation. Biomed Chromatogr 2013; 28:182-91. [DOI: 10.1002/bmc.3072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/17/2013] [Accepted: 09/20/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Ans Hendrickx
- Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research; Vrije Universiteit Brussel-VUB; Laarbeeklaan 103 1090 Brussels Belgium
| | - Katrijn De Klerck
- Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research; Vrije Universiteit Brussel-VUB; Laarbeeklaan 103 1090 Brussels Belgium
| | - Debby Mangelings
- Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research; Vrije Universiteit Brussel-VUB; Laarbeeklaan 103 1090 Brussels Belgium
| | - Lies Clincke
- Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research; Vrije Universiteit Brussel-VUB; Laarbeeklaan 103 1090 Brussels Belgium
| | - Yvan Vander Heyden
- Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research; Vrije Universiteit Brussel-VUB; Laarbeeklaan 103 1090 Brussels Belgium
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2
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Zhang X, Yang J, Liu S, Lin X, Xie Z. Branched polyethyleneimine-bonded tentacle-type polymer stationary phase for peptides and proteins separations by open-tubular capillary electrochromatography. J Sep Sci 2011; 34:3383-91. [DOI: 10.1002/jssc.201100545] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/28/2011] [Accepted: 09/13/2011] [Indexed: 11/08/2022]
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3
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Kadi A, Hefnawy M, Al-Majed A, Alonezi S, Asiri Y, Attia S, Abourashed E, El-Subbagh H. Liquid chromatographic high-throughput analysis of the new ultra-short acting hypnotic ‘HIE-124’ and its metabolite in mice serum using a monolithic silica column. Analyst 2011; 136:591-7. [DOI: 10.1039/c0an00381f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Liu H, Han N, Zhang L, Du Y, Zhang W. Design and evaluation of capillary electrophoresis in dynamically coated capillaries coupled with chemiluminescence detection. Anal Chim Acta 2010; 680:48-53. [DOI: 10.1016/j.aca.2010.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 08/28/2010] [Accepted: 09/09/2010] [Indexed: 12/01/2022]
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5
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Chen XJ, Yang FQ, Wang YT, Li SP. CE and CEC of nucleosides and nucleotides in food materials. Electrophoresis 2010; 31:2092-105. [PMID: 20593386 DOI: 10.1002/elps.201000048] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dietary nucleosides and nucleotides play an important role in the maintenance of functions of bone marrow hematopoietic cells, intestinal mucosa, and brain. Therefore, analysis of those compounds in food is very important for improving and assuring food quality. This review summarized the application of CE and CEC in the analysis of nucleosides and nucleotides in food. The sample preparation and detection are also discussed.
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Affiliation(s)
- Xiao-Jia Chen
- Institute of Chinese Medical Sciences, University of Macau, Macao SAR, PR China
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6
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Abstract
Although there are many publications related to technological or methodological developments of CEC, few focus on the analysis of natural products, especially phytochemical bioactive compounds. This review summarized the application of CEC in the analysis of phytochemical bioactive components, including flavonoids, nucleosides, steroids, lignans, quinones and coumarins, as well as fingerprint analysis of herbs. The strategies for optimization of CEC conditions and detection were also discussed.
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Affiliation(s)
- Feng-qing Yang
- Department of Pharmaceutics, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
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7
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Cordell RL, Hill SJ, Ortori CA, Barrett DA. Quantitative profiling of nucleotides and related phosphate-containing metabolites in cultured mammalian cells by liquid chromatography tandem electrospray mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 871:115-24. [PMID: 18650133 DOI: 10.1016/j.jchromb.2008.07.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 07/08/2008] [Accepted: 07/09/2008] [Indexed: 11/19/2022]
Abstract
A method has been developed for the quantitative profiling of over twenty nucleotides and related phosphorylated species using ion-pair reversed-phase liquid chromatography hyphenated to negative ion tandem electrospray mass spectrometry. The influence of mobile phase pH and ion-pairing agent concentration were assessed to optimise separation and peak shapes. Full quantitative analysis was obtained for the nucleotides by reference to structurally related calibration standards. The developed method was applied to profile changes in nucleotides and related compounds in monolayer cultured Chinese hamster ovary (CHO) cells expressing the beta(2) adrenoceptor when exposed to pharmacological stimuli. These experiments demonstrate the potential of the LC-MS/MS method to detect changes in nucleotide drug targets as well as the simultaneous monitoring of levels of other nucleotides.
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Affiliation(s)
- Rebecca L Cordell
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, UK
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8
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Geiser L, Eeltink S, Svec F, Fréchet JMJ. In-line system containing porous polymer monoliths for protein digestion with immobilized pepsin, peptide preconcentration and nano-liquid chromatography separation coupled to electrospray ionization mass spectroscopy. J Chromatogr A 2008; 1188:88-96. [PMID: 18342870 PMCID: PMC2435401 DOI: 10.1016/j.chroma.2008.02.075] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 02/10/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
The use of two different monoliths located in capillaries for on-line protein digestion, preconcentration of peptides and their separation has been demonstrated. The first monolith was used as support for covalent immobilization of pepsin. This monolith with well-defined porous properties was prepared by in situ copolymerization of 2-vinyl-4,4-dimethylazlactone and ethylene dimethacrylate. The second, poly(lauryl methacrylate-co-ethylene dimethacrylate) monolith with a different porous structure served for the preconcentration of peptides from the digest and their separation in reversed-phase liquid chromatography mode. The top of the separation capillary was used as a preconcentrator, thus enabling the digestion of very dilute solutions of proteins in the bioreactor and increasing the sensitivity of the mass spectrometric detection of the peptides using a time-of-flight mass spectrometer with electrospray ionization. Myoglobin, albumin, and hemoglobin were digested to demonstrate feasibility of the concept of using the two monoliths in-line. Successive protein injections confirmed both the repeatability of the results and the ability to reuse the bioreactor for at least 20 digestions.
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Affiliation(s)
- Laurent Geiser
- Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA
| | - Sebastiaan Eeltink
- Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA
| | - Frantisek Svec
- The Molecular Foundry, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8139, USA
| | - Jean M. J. Fréchet
- Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA
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9
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Separation of oxidatively damaged DNA nucleobases and nucleosides on packed and monolith C18 columns by HPLC-UV-EC. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 863:181-6. [DOI: 10.1016/j.jchromb.2008.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 12/21/2007] [Accepted: 01/02/2008] [Indexed: 11/20/2022]
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10
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Svec F, Kurganov AA. Less common applications of monoliths. III. Gas chromatography. J Chromatogr A 2007; 1184:281-95. [PMID: 17645884 PMCID: PMC2293291 DOI: 10.1016/j.chroma.2007.07.014] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 07/06/2007] [Accepted: 07/09/2007] [Indexed: 11/29/2022]
Abstract
Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography.
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Affiliation(s)
- Frantisek Svec
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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11
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Abstract
This review summarizes applications of CEC for the analysis of proteins and peptides. This "hybrid" technique is useful for the analysis of a broad spectrum of proteins and peptides and is a complementary approach to liquid chromatographic and capillary electrophoretic analysis. All modes of CEC are described--granular packed columns, monolithic stationary phases as well as open-tubular CEC. Attention is also paid to pressurized CEC and the chip-based platform.
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Affiliation(s)
- Ivan Miksík
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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12
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Ohyama K, Kuroda N. Capillary Electrochromatography of Charged Biomolecules with Mixed‐Mode Stationary Phases. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701191128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Kaname Ohyama
- a Department of Hospital Pharmacy , Nagasaki University Hospital of Medicine and Dentistry , Nagasaki , Japan
| | - Naotaka Kuroda
- b Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University , Nagasaki , Japan
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13
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Weissinger EM, Hertenstein B, Mischak H, Ganser A. Online coupling of capillary electrophoresis with mass spectrometry for the identification of biomarkers for clinical diagnosis. Expert Rev Proteomics 2006; 2:639-47. [PMID: 16209644 DOI: 10.1586/14789450.2.5.639] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Proteomic screening of complex biologic samples is of increasing importance in clinical research and diagnosis. In the postgenomic area it is evident that changes of the composition of body fluids, as well as post-translational modifications of proteins and peptides, provide more information than genetic typing. The study of these changes allows the state of health or disease of particular organs, and consequently, the whole organism, to be described. This review describes the application of capillary electrophoresis coupled online to an electrospray ionization time-of-flight mass spectrometer to the analysis of body fluids obtained from patients for the identification of biomarkers for diagnostic purposes.
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Affiliation(s)
- Eva M Weissinger
- Department of Hematology, Hemostasis & Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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14
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Huang YF, Huang CC, Hu CC, Chang HT. Capillary electrophoresis-based separation techniques for the analysis of proteins. Electrophoresis 2006; 27:3503-22. [PMID: 16927348 DOI: 10.1002/elps.200600100] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CE offers the advantages of high speed, great efficiency, as well as the requirement of minimum amounts of sample and buffer for the analysis of proteins. In this review, we summarize the CE-based techniques coupled with absorption, LIF, and MS detection systems for the analysis of proteins mostly within the past 5 years. The basic principle of each technique and its advantages and disadvantages for protein analysis are discussed in brief. Advanced CE techniques, including on-column concentration techniques and high-efficiency multidimensional separation techniques, for high-throughput protein profiling of complex biological samples and/or of single cells are emphasized. Although the developed techniques provide improved peak capacity, they have not become practical tools for proteomics, mainly because of poor reproducibility, low-sample lading capacity, and low throughput due to ineffective interfaces between two separation dimensions and that between separation and MS systems. In order to identify the complexities and dynamics of the proteomes expressed by cells, tissues, or organisms, techniques providing improved analytical sensitivity, throughput, and dynamic ranges are still demanded.
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Affiliation(s)
- Yu-Fen Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
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15
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Svec F. Less common applications of monoliths: Preconcentration and solid-phase extraction. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 841:52-64. [PMID: 16650811 DOI: 10.1016/j.jchromb.2006.03.055] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 03/24/2006] [Accepted: 03/27/2006] [Indexed: 11/22/2022]
Abstract
Monolithic materials are finding their place in a variety of fields. While liquid chromatography is the most emphasized use of this new category of porous media, some other just as important applications are eclipsed by the success of monolithic columns. This review article describes all current facets of use of monoliths in preconcentration and solid-phase extraction. In addition to the typical off line use that does not seem to be the main stream application for the monolithic materials, in-line connection of the preconcentration with HPLC, electrochromatography, electrophoresis, enzymatic digestion, as well as its applications in microfluidics are presented.
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Affiliation(s)
- Frantisek Svec
- The Molecular Foundry, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8139, USA.
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16
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Ahrer K, Jungbauer A. Chromatographic and electrophoretic characterization of protein variants. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 841:110-22. [PMID: 16872917 DOI: 10.1016/j.jchromb.2006.05.044] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 05/23/2006] [Accepted: 05/28/2006] [Indexed: 11/17/2022]
Abstract
Almost all proteins are expressed in several variants, also known as isoforms. Individual protein variants differ by modifications of the individual amino acid side chains, or the N- or C-terminus. Typical modifications are glycosylation, phosphorylation, acetylation, methylation, deamidation or oxidation. It is of utmost interest to either get a quantitative picture of the variants of a particular protein or to separate the variants in order to be able to identify their molecular structure. Protein variants are present in native as well as in recombinant proteins. In the case of protein production it is interesting, how variants are generated during fermentation, purification processes, storage, and how present individual variants influence the biological activity. This review provides a comparison of chromatographic and electrophoretic separation methods to analyze and to prepare protein variants.
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Affiliation(s)
- Karin Ahrer
- Department of Biotechnology, University of Natural Resources and Applied Life Sciences and Austrian Center of Biopharmaceutical Technology, Vienna, Muthgasse 18, A-1190 Vienna, Austria
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17
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Iqbal J, Burbiel JC, Müller CE. Development of off-line and on-line capillary electrophoresis methods for the screening and characterization of adenosine kinase inhibitors and substrates. Electrophoresis 2006; 27:2505-17. [PMID: 16786483 DOI: 10.1002/elps.200500944] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Fast and convenient CE assays were developed for the screening of adenosine kinase (AK) inhibitors and substrates. In the first method, the enzymatic reaction was performed in a test tube and the samples were subsequently injected into the capillary by pressure and detected by their UV absorbance at 260 nm. An MEKC method using borate buffer (pH 9.5) containing 100 mM SDS (method A) was suitable for separating alternative substrates (nucleosides). For the CE determination of AMP formed as a product of the AK reaction, a phosphate buffer (pH 7.5 or 8.5) was used and a constant current (95 microA) was applied (method B). The methods employing a fused-silica capillary and normal polarity mode provided good resolution of substrates and products of the enzymatic reaction and a short analysis time of less than 10 min. To further optimize and miniaturize the AK assays, the enzymatic reaction was performed directly in the capillary, prior to separation and quantitation of the product employing electrophoretically mediated microanalysis (EMMA, method C). After hydrodynamic injection of a plug of reaction buffer (20 mM Tris-HCl, 0.2 mM MgCl2, pH 7.4), followed by a plug containing the enzyme, and subsequent injection of a plug of reaction buffer containing 1 mM ATP, 100 microM adenosine, and 20 microM UMP as an internal standard (I.S.), as well as various concentrations of an inhibitor, the reaction was initiated by the application of 5 kV separation voltage (negative polarity) for 0.20 min to let the plugs interpenetrate. The voltage was turned off for 5 min (zero-potential amplification) and again turned on at a constant current of -60 microA to elute the products within 7 min. The method employing a polyacrylamide-coated capillary of 20 cm effective length and reverse polarity mode provided good resolution of substrates and products. Dose-response curves and calculated K(i) values for standard antagonists obtained by CE were in excellent agreement with data obtained by the standard radioactive assay.
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Affiliation(s)
- Jamshed Iqbal
- Department of Pharmaceutical Chemistry Poppelsdorf, Pharmaceutical Institute, University of Bonn, Bonn, Germany
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18
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Svec F. Less common applications of monoliths: I. Microscale protein mapping with proteolytic enzymes immobilized on monolithic supports. Electrophoresis 2006; 27:947-61. [PMID: 16470758 DOI: 10.1002/elps.200500661] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This review summarizes the recent contributions to the rapidly growing area of immobilized enzymes employing both silica and synthetic polymer-based monoliths as supports. Focus is mainly on immobilized proteolytic enzyme reactors designed for studies in proteomics. Porous monoliths emerged first as a new class of stationary phases for HPLC in the early 1990s. Soon thereafter, they were also used as supports for immobilization of proteins and preparation of both stationary phases for bioaffinity chromatography and enzymatic reactors. Organic polymer-based monoliths are typically prepared using a simple molding process carried out within the confines of a "mold" such as chromatographic column or capillary. Polymerization of a mixture comprising monomers, initiator, and porogenic solvent affords macroporous materials. In contrast, silica-based monoliths are first formed as a rigid rod from tetraalkoxysilane in the presence of PEG and subsequently encased with a plastic tube. Both types of monolith feature large through-pores that enable a rapid flow-through. Since all the solutions must flow through the monolith, the convection considerably accelerates mass transfer within the monolith. As a result, reactors including enzyme immobilized on monolithic support exhibit much higher activity compared to the reactions in solution.
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Affiliation(s)
- Frantisek Svec
- Department of Chemistry, University of California, Berkeley, CA, USA.
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19
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Kolch W, Neusüss C, Pelzing M, Mischak H. Capillary electrophoresis-mass spectrometry as a powerful tool in clinical diagnosis and biomarker discovery. MASS SPECTROMETRY REVIEWS 2005; 24:959-977. [PMID: 15747373 DOI: 10.1002/mas.20051] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Proteome analysis is now emerging as key technology for deciphering biological processes and the discovery of biomarkers for diseases from tissues and body fluids. The complexity and wide dynamic range of protein expression poses a formidable challenge to both peptide separation technologies and mass spectrometry (MS). Here we review the efforts that have been undertaken to date, focussing on capillary electrophoresis coupled to mass spectrometry (CE-MS). We discuss CE-MS from an application point of view evaluating its merits and vices in regard to biomarker discovery and clinical applications. As examples, we present the use of CE-MS for the determination of protein patterns in urine, serum, and other body fluids. Finally, the benefits and limitations of CE-MS for the analysis of proteins in clinical samples are discussed against the background of alternative technologies.
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Affiliation(s)
- Walter Kolch
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, United Kingdom
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20
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Rieux L, Niederländer H, Verpoorte E, Bischoff R. Silica monolithic columns: Synthesis, characterisation and applications to the analysis of biological molecules. J Sep Sci 2005; 28:1628-41. [PMID: 16224956 DOI: 10.1002/jssc.200500146] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In recent years, proteomics has been a subject of intense research. The complexity of proteomics samples has fostered technological developments. One of these addresses the need for more efficient and faster separations. Monolithic columns prepared from organic and silica monomers offer very efficient separations at low back-pressure. Silica-based monoliths have small-sized skeletons and a bimodal pore size distribution with microm-sized throughpores and nm-sized mesopores. This gives silica-based monoliths favourable properties for high-efficiency, fast separations, like a low-pressure drop across the column, fast mass transfer kinetics and a high binding capacity.
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Affiliation(s)
- Laurent Rieux
- Pharmaceutical Analysis, University Centre for Pharmacy, University of Groningen, Groningen, The Netherlands
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21
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Ohyama K, Wada M, Kishikawa N, Ohba Y, Nakashima K, Kuroda N. Stepwise gradient of buffer concentration for capillary electrochromatography of peptides on sulfonated naphthalimido-modified silyl silica gel. J Chromatogr A 2005; 1064:255-9. [PMID: 15739894 DOI: 10.1016/j.chroma.2004.12.052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The advantage of using a stepwise gradient of buffer concentration in CEC was demonstrated with the mixed-mode stationary phase, 3-(4-sulfo-1,8-naphthalimido)propyl-modified silyl silica gel (SNAIP). Before the application of a stepwise gradient, the effect of buffer concentration on the separations of six peptides and tryptic digests was investigated. Bubble formation caused by Joule heating at currents up to 95 microA was successfully suppressed by using SNAIP column even without pressurization, which contributed to a stepwise gradient of buffer concentration. Utilizing the stepwise gradient improved and shortened the separation of six peptides as compared to the separation under an isocratic elution.
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Affiliation(s)
- Kaname Ohyama
- Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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22
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Ohyama K, Fujimoto E, Wada M, Kishikawa N, Ohba Y, Akiyama S, Nakashima K, Kuroda N. Investigation of a novel mixed-mode stationary phase for capillary electrochromatography. Part III: Separation of nucleosides and nucleic acid bases on sulfonated naphthalimido-modified silyl silica gel. J Sep Sci 2005; 28:767-73. [PMID: 15938185 DOI: 10.1002/jssc.200500030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Capillary electrochromatography (CEC) with a novel stationary phase, 3-(4-sulfo-1,8-naphthalimido)propyl-modified silyl silica gel (SNAIP), proved useful for the separation of nucleosides and nucleic acid bases. The application scope of SNAIP, which is a relatively polar reversed-phase (RP)-type stationary phase, was successfully expanded to include the CEC separation of polar compounds although the combination of non-polar RP phase with highly aqueous mobile phase is often inadequate. Due to the permanently charged sulfonic acid groups and the naphthalimidopropyl moiety, the retention of charged and relatively polar nucleosides as well as bases on the SNAIP stationary phase was effected by electrostatic and hydrophobic interactions. This yielded a unique selectivity on SNAIP toward nucleosides and bases. The characteristic EOF on SNAIP, which was stronger at higher aqueous content in the mobile phase, proved suitable for the separation of polar compounds in reversed-phase mode with highly aqueous mobile phase. In addition, when a double stepwise gradient was employed to accelerate the latest peak (adenine), the elution time was shortened to less than half its original duration.
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Affiliation(s)
- Kaname Ohyama
- Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan
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23
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Abstract
This review discusses the development of capillary electrochromatography (CEC) coupled to mass spectrometric (MS) detection over the last few years. Major topics addressed are instrumental setups employed and applications of this technology published in the recent literature. The instrumental section includes a discussion of the most commonly used interfaces for the hyphenation of CEC and MS as well as ionization techniques. Applications reviewed in this paper come from a variety of different fields such as the analysis of biomolecules like proteins, peptides, amino acids or carbohydrates, chiral separations or the analysis of pharmaceutical an their metabolites in a series of matrices.
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Affiliation(s)
- Christian W Klampfl
- Institute of Analytical Chemistry, Johannes-Kepler-University, Altenbergerstrasse 69, A-4040 Linz, Austria.
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24
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Ohyama K, Fujimoto E, Wada M, Kishikawa N, Ohba Y, Akiyama S, Nakashima K, Kuroda N. Investigation of a novel mixed-mode stationary phase for capillary electrochromatography. Part III1): Separation of nucleosides and nucleic acid bases on sulfonated naphthalimido-modified silyl silica gel. J Sep Sci 2005. [DOI: 10.1002/jssc.200400030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Dick LW, Swinteck BJ, McGown LB. Albumins as a model system for investigating separations of closely related proteins on DNA stationary phases in capillary electrochromatography. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.04.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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26
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Ohyama K, Shirasawa Y, Wada M, Kishikawa N, Ohba Y, Nakashima K, Kuroda N. Investigation of the novel mixed-mode stationary phase for capillary electrochromatography. J Chromatogr A 2004; 1042:189-95. [PMID: 15296405 DOI: 10.1016/j.chroma.2004.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A novel packing material, 3-(4-sulfo-1,8-naphthalimido)propyl-modified silyl silica gel (SNAIP), was prepared for the use as a stationary phase of capillary electrochromatography (CEC). The sulfonic acid groups on SNAIP stationary phase contributed to the generation of electroosmotic flow (EOF) at low pH and served as a strong cation-exchanger. In CEC with SNAIP, a mixed-mode separation was predicted, comprising hydrophobic and electrostatic interactions as well as electrophoretic migration process. In order to understand the retention mechanism on SNAIP, effects of buffer pH, concentration, and mobile phase composition on EOF mobility and the retention factors of barbiturates and benzodiazepines were systematically investigated. Moreover, the retention behavior of barbiturates on SNAIP was investigated and compared with those on octadecyl silica (ODS), phenyl-bonded silica, and 3-(1,8-naphthalimido)propyl-modified silyl silica gel to confirm the presence of pi-pi interaction on its retention mechanism. It was observed that a column efficiency was more than 85,000 N/m for retained compounds and the relative standard deviations for the retention times of EOF marker, thiourea, and five barbiturates were below 2.5% (n = 4). Under an applied voltage of 20 kV and a mobile phase consisted of 5 mM phosphate (pH 3.8) and 40% methanol, the baseline separation of five barbiturates was achieved within 3 min.
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Affiliation(s)
- Kaname Ohyama
- Department of Analytical Chemistry, Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Guihen E, Glennon JD. Recent highlights in stationary phase design for open-tubular capillary electrochromatography. J Chromatogr A 2004; 1044:67-81. [PMID: 15354429 DOI: 10.1016/j.chroma.2004.05.107] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This review examines the most recent innovations made to achieve high performance in open-tubular capillary electrochromatography (OT-CEC) separations, focusing on the ingenious chemical and physical solutions made to increase the surface area and equip the stationary phase with exploitable selectivity. Among the approaches taken are chemically bonded ligands, etching with chemical bonding, sol-gels, molecularly imprinted polymers, porous layers, physically attached or adsorbed phases, and nanoparticle coatings. Particularly noteworthy are modern developments with macrocyclic receptor ligands, nanoparticles and open channel electrochromatography on-chip.
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Affiliation(s)
- Elizabeth Guihen
- Department of Chemistry, Analytical and Biological Chemistry Research Facility, University College Cork, Cork, Ireland
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Abstract
Rigid porous polymer monoliths are a new class of materials that emerged in the early 1990s. These monolithic materials are typically prepared using a simple molding process carried out within the confines of a closed mold. For example, polymerization of a mixture comprising monomers, free-radical initiator, and porogenic solvent affords macroporous materials with large through-pores that enable applications in a rapid flow-through mode. The versatility of the preparation technique is demonstrated by its use with hydrophobic, hydrophilic, ionizable, and zwitterionic monomers. Several system variables can be used to control the porous properties of the monolith over a broad range and to mediate the hydrodynamic properties of the monolithic devices. A variety of methods such as direct copolymerization of functional monomers, chemical modification of reactive groups, and grafting of pore surface with selected polymer chains is available for the control of surface chemistry. Since all the mobile phase must flow through the monolith, the convection considerably accelerates mass transport within the molded material, and the monolithic devices perform well, even at very high flow rates. The applications of polymeric monolithic materials are demonstrated mostly on the separations in the HPLC mode, although CEC, gas chromatography, enzyme immobilization, molecular recognition, advanced detection systems, and microfluidic devices are also mentioned.
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Affiliation(s)
- Frantisek Svec
- Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA.
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