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Glatz Z. On-capillary derivatisation as an approach to enhancing sensitivity in capillary electrophoresis. Electrophoresis 2014; 36:744-63. [DOI: 10.1002/elps.201400449] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 10/09/2014] [Accepted: 10/11/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Zdeněk Glatz
- Department of Biochemistry; Faculty of Science and CEITEC; Masaryk University; Brno Czech Republic
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Kazarian AA, Hilder EF, Breadmore MC. Online sample pre-concentration via dynamic pH junction in capillary and microchip electrophoresis. J Sep Sci 2011; 34:2800-21. [DOI: 10.1002/jssc.201100414] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Huang L, Lin Q, Chen Y, Chen G. Transient isotachophoresis with field-amplified sample injection for on-line preconcentration and enantioseparation of some β-agonists. Anal Methods 2011; 3:294-298. [PMID: 32938027 DOI: 10.1039/c0ay00556h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transient isotachophoresis with field-amplified sample injection (FASI), using β-CD as the chiral selector and tetrabutylammonium hydroxide (TBAOH) as the additive, was applied for on-line preconcentration and enantioseparation of three β-agonists, namely, cimaterol, clenbuterol and terbutaline. The experimental conditions for both simultaneous enantioseparation and on-line preconcentration methods have been investigated in detail. Under the optimum conditions, the detection limits (defined as S/N = 3) of this method were found to be 1 ng mL-1 for all three pairs of β-agonists enantiomers. Compared with conventional electrokinetic injection, the enhancement factors were greatly improved to be 250-fold. Finally, the proposed method has been applied for the analysis of human urine samples.
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Affiliation(s)
- Lu Huang
- Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Qi Lin
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Yiting Chen
- Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Guonan Chen
- Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
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Gavina JMA, White CE, Finan TM, Britz-McKibbin P. Determination of 4-hydroxyproline-2-epimerase activity by capillary electrophoresis: A stereoselective platform for inhibitor screening of amino acid isomerases. Electrophoresis 2010; 31:2831-7. [DOI: 10.1002/elps.201000187] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
An analysis of recent trends indicates that CE can show real advantages over chromatographic methods in ultratrace enantioselective determination of biologically active compounds in complex biological matrices. It is due to high separation efficiency and many applicable in-capillary electromigration effects in CE (countercurrent migration, stacking effects) enhancing significantly (enantio)separability and enabling effective sample preparation (preconcentration, purification, analyte derivatization). Other possible on-line combinations of CE, such as column coupled CE-CE techniques and implementation of nonelectrophoretic techniques (extraction, membrane filtration, flow injection) into CE, offer additional approaches for highly effective sample preparation and separation. CE matured to a highly flexible and compatible technique enabling its hyphenation with powerful detection systems allowing extremely sensitive detection (e.g. LIF) and/or structural characterization of analytes (e.g. MS). Within the last decade, more as well as less conventional analytical on-line approaches have been effectively utilized in this field and their practical potentialities are demonstrated on many new application examples in this article. Here, three basic areas of (enantioselective) drug bioanalysis are highlighted and supported by a brief theoretical description of each individual approach in a compact review structure (to create integrated view on the topic), including (i) progressive enantioseparation approaches and new enantioselective agents, (ii) in-capillary sample preparation (preconcentration, purification, derivatization), and (iii) detection possibilities related to enhanced sensitivity and structural characterization.
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Affiliation(s)
- Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.
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Abstract
A novel method capable of differentiating and concentrating small molecules in bulk solution termed "electrophoretic exclusion" is described and experimentally investigated. In this technique, the hydrodynamic flow of the system is countered by the electrophoretic velocity to prevent a species from entering into the channel. The separation can be controlled by changing the flow rate or applied electric field in order to exclude certain species selectively while allowing others to pass through the capillary. Proof of principle studies employed a flow injection regime of the method and examined the exclusion of Methyl Violet dye in the presence of a neutral species. Methyl Violet was concentrated almost 40 times the background concentration in 30 s using 6 kV. Additionally, a threshold voltage necessary for exclusion was determined. The establishment of a threshold voltage enabled the differentiation of two similar cationic species: Methyl Green and Neutral Red.
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Yan N, Zhou L, Zhu Z, Zhang H, Zhou X, Chen X. Constant pressure-assisted head-column field-amplified sample injection in combination with in-capillary derivatization for enhancing the sensitivity of capillary electrophoresis. J Chromatogr A 2009; 1216:4517-23. [DOI: 10.1016/j.chroma.2009.03.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 03/10/2009] [Accepted: 03/17/2009] [Indexed: 11/17/2022]
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Su S, Yu Y. Online preconcentration of recombinant Arg-Gly-Asp-hirudin using dynamic pH junction for analysis in human urine samples by capillary electrophoresis-mass spectrometry. J Chromatogr A 2009; 1216:1490-5. [DOI: 10.1016/j.chroma.2008.12.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Revised: 11/20/2008] [Accepted: 12/19/2008] [Indexed: 10/21/2022]
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Nesbitt CA, Zhang H, Yeung KK. Recent applications of capillary electrophoresis–mass spectrometry (CE–MS): CE performing functions beyond separation. Anal Chim Acta 2008; 627:3-24. [DOI: 10.1016/j.aca.2008.04.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/02/2008] [Accepted: 04/08/2008] [Indexed: 11/18/2022]
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Simpson SL, Quirino JP, Terabe S. On-line sample preconcentration in capillary electrophoresis. J Chromatogr A 2008; 1184:504-41. [DOI: 10.1016/j.chroma.2007.11.001] [Citation(s) in RCA: 269] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 10/30/2007] [Accepted: 11/01/2007] [Indexed: 02/06/2023]
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Abstract
Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in-line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10,000- to 100,000-fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.
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Affiliation(s)
- Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
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Monton MRN, Soga T. Metabolome analysis by capillary electrophoresis-mass spectrometry. J Chromatogr A 2007; 1168:237-46; discussion 236. [PMID: 17376458 DOI: 10.1016/j.chroma.2007.02.065] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 01/26/2007] [Accepted: 02/20/2007] [Indexed: 10/23/2022]
Abstract
Capillary electrophoresis (CE)-mass spectrometry (MS), as an analytical platform, has made significant contributions in advancing metabolomics research, if still limited up to this time. This review, covering reports published between 1998 and 2006, describes how CE-MS has been used thus far in this field, with the majority of the works dealing with targeted metabolite analyses and only a small fraction using it in the comprehensive context. It also discusses how some of the key features of CE-MS were exploited in selected metabolomic applications.
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Affiliation(s)
- Maria Rowena N Monton
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan
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Lee R, Ptolemy AS, Niewczas L, Britz-McKibbin P. Integrative Metabolomics for Characterizing Unknown Low-Abundance Metabolites by Capillary Electrophoresis-Mass Spectrometry with Computer Simulations. Anal Chem 2007; 79:403-15. [PMID: 17222002 DOI: 10.1021/ac061780i] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Characterization of unknown low-abundance metabolites in biological samples is one the most significant challenges in metabolomic research. In this report, an integrative strategy based on capillary electrophoresis-electrospray ionization-ion trap mass spectrometry (CE-ESI-ITMS) with computer simulations is examined as a multiplexed approach for studying the selective nutrient uptake behavior of E. coli within a complex broth medium. On-line sample preconcentration with desalting by CE-ESI-ITMS was performed directly without off-line sample pretreatment in order to improve detector sensitivity over 50-fold for cationic metabolites with nanomolar detection limits. The migration behavior of charged metabolites were also modeled in CE as a qualitative tool to support MS characterization based on two fundamental analyte physicochemical properties, namely, absolute mobility (muo) and acid dissociation constant (pKa). Computer simulations using Simul 5.0 were used to better understand the dynamics of analyte electromigration, as well as aiding de novo identification of unknown nutrients. There was excellent agreement between computer-simulated and experimental electropherograms for several classes of cationic metabolites as reflected by their relative migration times with an average error of <2.0%. Our studies revealed differential uptake of specific amino acids and nucleoside nutrients associated with distinct stages of bacterial growth. Herein, we demonstrate that CE can serve as an effective preconcentrator, desalter, and separator prior to ESI-MS, while providing additional qualitative information for unambiguous identification among isobaric and isomeric metabolites. The proposed strategy is particularly relevant for characterizing unknown yet biologically relevant metabolites that are not readily synthesized or commercially available.
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Affiliation(s)
- Richard Lee
- Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
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Zacharis CK, Tempels FWA, Theodoridis GA, Voulgaropoulos AN, Underberg WJM, Somsen GW, de Jong GJ. Coupling of sequential injection analysis and capillary electrophoresis - Laser-induced fluorescence via a valve interface for on-line derivatization and analysis of amino acids and peptides. J Chromatogr A 2006; 1132:297-303. [PMID: 16919652 DOI: 10.1016/j.chroma.2006.07.076] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 07/20/2006] [Accepted: 07/28/2006] [Indexed: 10/24/2022]
Abstract
The on-line coupling of sequential injection analysis (SIA) and capillary electrophoresis (CE) via an in-line injection valve is presented. The SIA system is used for automated derivatization of amino acids and peptides. Dichlorotriazinylaminofluorescein serves as the derivatization agent, thus enabling sensitive laser-induced fluorescence detection of the derivatized analytes. The SIA procedure includes the following steps: (a) introduction of reagent and sample zones in a holding coil, (b) sample and reagent mixing in a reaction coil, (c) stop-flow step for increase of the reaction time, and (d) delivery of derivatized sample into the loop of the micro-valve interface. A small portion of the analyte zone is introduced electrokinetically in the separation capillary via the valve interface and CE analysis is performed. Factors affecting the CE separation, such as pH, the borate and sodium dodecyl sulphate concentration of the background electrolyte have been optimized. The derivatization conditions have been studied to obtain a high reaction yield in a relative short time. The transfer of a part of the reaction plug into the loop of the valve interface has been optimized. Using des-Tyr(1)-[Met]-enkephalinamide as test compound, it is demonstrated that after automated derivatization, on-line electrophoretic analysis could be achieved. Glycine has been selected as the internal standard in order to correct for variations in reaction time and filling of the injection loop. For the enkephalin, good reproducibility (RSD<4.5% calculated by the ratio of the peak areas) and linearity (0.5-5 microg mL(-1), R(2)>or=0.994) are obtained with a detection limit of 30 ng mL(-1) (S/N=3).
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Affiliation(s)
- Constantinos K Zacharis
- Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University Thessaloniki, 541 24 Thessaloniki, Greece
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Ptolemy AS, Tran L, Britz-McKibbin P. Single-step enantioselective amino acid flux analysis by capillary electrophoresis using on-line sample preconcentration with chemical derivatization. Anal Biochem 2006; 354:192-204. [PMID: 16753129 DOI: 10.1016/j.ab.2006.04.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 03/15/2006] [Accepted: 04/13/2006] [Indexed: 10/24/2022]
Abstract
Capillary electrophoresis (CE) represents a versatile platform for integrating sample pretreatment with chemical analysis because of its ability to tune analyte electromigration and band dispersion properties in discontinuous electrolyte systems. In this article, a single-step method that combines on-line sample preconcentration with in-capillary chemical derivatization is developed for rapid, sensitive, and enantioselective analysis of micromolar levels of amino acids that lack intrinsic chromophores by CE with UV detection. Time-resolved electrophoretic studies revealed two distinct stages of amino acid band narrowing within the original long sample injection plug occurring both prior to and after in-capillary labeling via zone passing by ortho-phthalaldehyde/N-acetyl l-cysteine (OPA/NAC). This technique enabled direct analysis of d-amino acids in a 95% enantiomeric excess mixture with sub-micromolar detection limits and minimal sample handling, where the capillary functions as a preconcentrator, microreactor, and chiral selector. On-line sample preconcentration with chemical derivatization CE (SPCD-CE) was applied to study the enantioselective amino acid flux in Escherichia coli bacteria cultures, which demonstrated a unique l-Ala efflux into the extracellular medium. New strategies for high-throughput analyses of low-abundance metabolites are important for understanding fundamental physiological processes in bacteria required for screening the efficacy of new classes of antibiotics as well as altered metabolism in genetically modified mutant strains.
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Affiliation(s)
- Adam S Ptolemy
- Department of Chemistry, McMaster University, Hamilton, Ont. L8S 4M1, Canada
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Ptolemy AS, Britz-McKibbin P. Sample preconcentration with chemical derivatization in capillary electrophoresis. Capillary as preconcentrator, microreactor and chiral selector for high-throughput metabolite screening. J Chromatogr A 2005; 1106:7-18. [PMID: 16336972 DOI: 10.1016/j.chroma.2005.11.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 11/03/2005] [Accepted: 11/04/2005] [Indexed: 11/15/2022]
Abstract
New strategies for integrating sample pretreatment with chemical analyses under a single format is required for rapid, sensitive and enantioselective analyses of low abundance metabolites in complex biological samples. Capillary electrophoresis (CE) offers a unique environment for controlling analyte/reagent band dispersion and electromigration properties using discontinuous electrolyte systems. Recent work in our laboratory towards developing a high-throughput CE platform for low abundance metabolites via on-line sample preconcentration with chemical derivatization (SPCD) is primarily examined in this review, as there have been surprisingly only a few strategies reported in the literature to date. In-capillary sample preconcentration serves to enhance concentration sensitivity via electrokinetic focusing of long sample injection volumes for lower detection limits, whereas chemical derivatization by zone passing is used to expand detectability and selectivity, notably for enantiomeric resolution of metabolites lacking intrinsic chromophores using nanolitre volumes of reagent. Together, on-line SPCD-CE can provide over a 100-fold improvement in concentration sensitivity, shorter total analysis times, reduced sample handling and improved reliability for a variety of amino acid and amino sugar metabolites, which is also amenable to automated high-throughput screening. This review will highlight basic method development and optimization parameters relevant to SPCD-CE, including applications to bacterial metabolite flux and biomarker analyses. Insight into the mechanism of analyte focusing and labeling by SPCD-CE is also discussed, as well as future directions for continued research.
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Affiliation(s)
- Adam S Ptolemy
- Department of Chemistry, McMaster University, Hamilton, Ont., Canada L8S 4M1
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