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Ohshiro K, Sasaki Y, Zhou Q, Lyu X, Yamanashi Y, Nakahara K, Nagaoka H, Minami T. Oxytocin detection at ppt level in human saliva by an extended-gate-type organic field-effect transistor. Analyst 2022; 147:1055-1059. [PMID: 35191913 DOI: 10.1039/d1an02188e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Herein, we report an extended-gate-type organic field-effect transistor (OFET) sensor for oxytocin. The fabricated OFET-based immunosensor has successfully detected oxytocin at a ppt level in human saliva with high recovery rates (96-102%). We believe our sensor would pave the way for the realization of portable sensors for healthcare monitoring.
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Affiliation(s)
- Kohei Ohshiro
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
| | - Yui Sasaki
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
| | - Qi Zhou
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
| | - Xiaojun Lyu
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
| | - Yusuke Yamanashi
- JNC Petrochemical Corp., 5-1, Goikaigan, Ichihara, Chiba, 290-8551, Japan
| | - Katsumasa Nakahara
- JNC Petrochemical Corp., 5-1, Goikaigan, Ichihara, Chiba, 290-8551, Japan
| | - Hirokazu Nagaoka
- JNC Petrochemical Corp., 5-1, Goikaigan, Ichihara, Chiba, 290-8551, Japan
| | - Tsuyoshi Minami
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
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2
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Guzman NA, Guzman DE. An emerging micro-scale immuno-analytical diagnostic tool to see the unseen. Holding promise for precision medicine and P4 medicine. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1021:14-29. [DOI: 10.1016/j.jchromb.2015.11.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/15/2015] [Accepted: 11/17/2015] [Indexed: 01/10/2023]
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3
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Seidi S, Yamini Y, Rezazadeh M. Electrochemically assisted solid based extraction techniques: A review. Talanta 2015; 132:339-53. [DOI: 10.1016/j.talanta.2014.08.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 11/25/2022]
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4
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Vizioli N, Gil R, Martínez LD, Fernanda Silva M. On-line solid phase extraction CZE for the simultaneous determination of lanthanum and gadolinium at picogram per liter levels. Electrophoresis 2009; 30:2681-7. [DOI: 10.1002/elps.200800819] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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5
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Hernández E, Benavente F, Sanz-Nebot V, Barbosa J. Evaluation of on-line solid phase extraction-capillary electrophoresis-electrospray-mass spectrometry for the analysis of neuropeptides in human plasma. Electrophoresis 2008; 29:3366-76. [DOI: 10.1002/elps.200700872] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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6
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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] [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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7
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Macià A, Borrull F, Calull M, Benavente F, Hernández E, Sanz-Nebot V, Barbosa J, Aguilar C. Sensitivity enhancement for the analysis of naproxen in tap water by solid-phase extraction coupled in-line to capillary electrophoresis. J Sep Sci 2008; 31:872-80. [DOI: 10.1002/jssc.200700593] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Tempels FWA, Underberg WJM, Somsen GW, de Jong GJ. Design and applications of coupled SPE-CE. Electrophoresis 2008; 29:108-28. [DOI: 10.1002/elps.200700149] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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9
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Hernández E, Benavente F, Sanz-Nebot V, Barbosa J. Analysis of opioid peptides by on-line SPE-CE-ESI-MS. Electrophoresis 2007; 28:3957-65. [DOI: 10.1002/elps.200700845] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Chen Y, Guo Z, Wang X, Qiu C. Sample preparation. J Chromatogr A 2007; 1184:191-219. [PMID: 17991475 DOI: 10.1016/j.chroma.2007.10.026] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 10/08/2007] [Accepted: 10/10/2007] [Indexed: 11/17/2022]
Abstract
A panorama of sample preparation methods has been composed from 481 references, with a highlight of some promising methods fast developed during recent years and a somewhat brief introduction on most of the well-developed methods. All the samples were commonly referred to molecular composition, being extendable to particles including cells but not to organs, tissues and larger bodies. Some criteria to evaluate or validate a sample preparation method were proposed for reference. Strategy for integration of several methods to prepare complicated protein samples for proteomic studies was illustrated and discussed.
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Affiliation(s)
- Yi Chen
- Beijing National Laboratory of Molecular Science, Laboratory of Analytical Chemistry for Life Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
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11
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Determination of selected elements by radionuclide X-ray fluorescence analysis after the separation on different kinds of sorption materials. J Radioanal Nucl Chem 2007. [DOI: 10.1007/s10967-007-7072-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Solínová V, Kasicka V, Sázelová P, Barth T, Miksík I. Separation and investigation of structure–mobility relationship of gonadotropin-releasing hormones by capillary zone electrophoresis in conventional and isoelectric acidic background electrolytes. J Chromatogr A 2007; 1155:146-53. [PMID: 17229433 DOI: 10.1016/j.chroma.2007.01.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 12/22/2006] [Accepted: 01/05/2007] [Indexed: 11/25/2022]
Abstract
Capillary zone electrophoresis (CZE) has been applied to qualitative and quantitative analysis, separation and physicochemical characterization of synthetic gonadotropin-releasing hormones (GnRHs) and their analogs and fragments. Structurally related peptides were separated in conventional and isoelectric acidic background electrolytes (BGEs), pH 2.18-2.50. Best separation was achieved in isoelectric BGE composed of 200 mM iminodiacetic acid, pH 2.32. The effective electrophoretic mobilities, m(ep), of GnRHs in five BGEs were determined and four semiempirical models correlating effective mobility with charge, q, and relative molecular mass, M(r), (m(ep) versus q/M(r)(k), where k is related to the molecular shape) were tested to describe the migration behavior of GnRHs in CZE. None of the models was found to be quite definitively applicable for the whole set of 10 GnRHs differing in size (tetrapeptide-decapeptide) and positive charge (0.91-3.00 elementary charges). Nevertheless, for the dependence of m(ep) on q/M(r)(k), the highest coefficient of correlation, R=0.995-0.999, was obtained for k close to the value 0.5 in all five acidic BGEs. This indicates that the most probable structure of GnRHs in these BGEs can be predicted as a random coil.
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Affiliation(s)
- Veronika Solínová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
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13
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Recent advances in coupling solid-phase extraction and capillary electrophoresis (SPE–CE). Trends Analyt Chem 2007. [DOI: 10.1016/j.trac.2007.05.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Galhiane MS, Rissato SR, Apon BM. Design of a Simple Detection Cell with Extended Optical Path Length for Capillary Electrophoresis: Application to Multiresidue Pesticide Analysis. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070500187533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Mário S. Galhiane
- a Department of Chemistry , Paulista State University (UNESP) , Bauru (SP), Brazil
| | - Sandra R. Rissato
- a Department of Chemistry , Paulista State University (UNESP) , Bauru (SP), Brazil
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15
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Saavedra L, Barbas C. Chromatography-based on- and in-line pre-concentration methods in capillary electrophoresis. ACTA ACUST UNITED AC 2006; 70:289-97. [PMID: 17196661 DOI: 10.1016/j.jbbm.2006.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
Capillary electrophoresis (CE) poses unique challenges in many different analytical applications, mainly to biological and complex samples and when only small amounts of sample are available, due to its low sample consumption. As a consequence, poor limits of detection are usually observed with this technique, especially with UV photodetectors. Minimal or no sample treatment is desirable in any analytical method to avoid external sources of contamination or errors and to provide a high throughput. On- and in-capillary sample pre-concentration strategies, based on solid-phase extraction (SPE) technology can take advantage of both techniques (SPE and CE), while avoiding sample contamination and tedious manipulations when the sample amount is an issue. Moreover, the combination can provide two-dimensional separations. This review collects the most recent strategies that merge SPE technology built on- and in-capillary pre-concentration for increasing sensitivity and/or selectivity.
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Affiliation(s)
- L Saavedra
- Sección de Química Analítica, Facultad de Farmacia, Universidad San Pablo-CEU, Campus Montepríncipe, 28668 Boadilla del Monte, Madrid, Spain
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16
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Monton MRN, Terabe S. Sample enrichment techniques in capillary electrophoresis: Focus on peptides and proteins. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 841:88-95. [PMID: 16716769 DOI: 10.1016/j.jchromb.2006.04.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 04/17/2006] [Accepted: 04/20/2006] [Indexed: 01/03/2023]
Abstract
Compared to chromatography-based techniques, the concentration limits of detection (CLOD) associated with capillary electrophoresis are worse, and these have largely precluded their use in many practical applications. To overcome this limitation, researchers from various disciplines have exerted tremendous efforts toward developing strategies for increasing the concentration sensitivities of capillary electrophoresis (CE) systems, via the so-called sample enrichment techniques. This review highlights selected developments and advances in this area as applied to the analyses of proteins and peptides in the last 5 years.
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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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17
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Kasicka V. Recent developments in capillary electrophoresis and capillary electrochromatography of peptides. Electrophoresis 2006; 27:142-75. [PMID: 16307429 DOI: 10.1002/elps.200500527] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The article gives a comprehensive review on the recent developments in the applications of high-performance capillary electromigration methods, zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography, to analysis, preparation, and physicochemical characterization of peptides. The article presents new approaches to the theoretical description and experimental verification of electromigration behavior of peptides, covers the methodological aspects of capillary electroseparations of peptides, such as rational selection of separation conditions, sample preparation, suppression of peptide adsorption, new developments in individual separation modes, and new designs of detection systems. Several types of applications of capillary electromigration methods to peptide analysis are presented: conventional qualitative and quantitative analysis, purity control, determination in biomatrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid and sequence analysis, and peptide mapping of proteins. Some examples of micropreparative peptide separations are given and capabilities of capillary electromigration techniques to provide important physicochemical characteristics of peptides are demonstrated.
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Affiliation(s)
- Václav Kasicka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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18
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Hutchinson JP, Macka M, Avdalovic N, Haddad PR. On-line preconcentration of organic anions in capillary electrophoresis by solid-phase extraction using latex-coated monolithic stationary phases. J Chromatogr A 2006; 1106:43-51. [PMID: 16443451 DOI: 10.1016/j.chroma.2005.08.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 07/28/2005] [Accepted: 08/08/2005] [Indexed: 10/25/2022]
Abstract
Quaternary ammonium functionalised polymeric latex particles were coated onto the wall of a fused-silica capillary or onto a methacrylate monolithic bed synthesised inside the capillary in order to create ion-exchange stationary phases of varying ion-exchange capacity. These capillaries were coupled in-line to a separation capillary and used for the solid-phase extraction (SPE), preconcentration and subsequent separation of organic anions by capillary electrophoresis. A transient isotachophoretic gradient was used for the elution of bound analytes from the SPE phase using two modes of separation. The first comprised a low capacity SPE column combined with a fluoride/octanesulfonate discontinuous electrolyte system in which peak compression occurred at the isotachophoretic gradient front. The compressed anions were separated electrophoretically after elution from the SPE preconcentration phase and resolution was achieved by altering the pH of the electrolyte in which the separation was performed. In the second approach, a latex-coated monolithic SPE preconcentration stationary phase was used in combination with a fluoride/perchlorate electrolyte system, which allowed capillary electrochromatographic separation to occur behind the isotachophoretic gradient front. This method permitted the removal of weakly bound anions from the SPE phase, thereby establishing the possibility of sample clean-up. The effect of the nature of the strong electrolyte forming the isotachophoretic gradient on the separation and also on the preconcentration step was investigated. Capillary electrochromatography of inorganic and organic species performed on the latex-coated monolithic methacrylate column highlighted the presence of mixed-mode interactions resulting from the incomplete coverage of latex particles onto the monolithic surface. Analyte preconcentration prior to separation resulted in compression of the analyte zone by a factor of 300. Improvement in the limit of detection of up to 10400 times could be achieved when performing the preconcentration step and the presented methods had limits of detection (S/N=3) ranging between 1.5 and 12 nM for the organic anions studied.
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Affiliation(s)
- Joseph P Hutchinson
- Australian Centre for Research on Separation Science (ACROSS), School of Chemistry, Faculty of Science, Engineering and Technology, University of Tasmania, Private Bag 75, Hobart 7001, Australia
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Vizioli NM, Rusell ML, Carbajal ML, Carducci CN, Grasselli M. On-line affinity selection of histidine-containing peptides using a polymeric monolithic support for capillary electrophoresis. Electrophoresis 2005; 26:2942-8. [PMID: 16007696 DOI: 10.1002/elps.200410416] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An on-line affinity selection method using a polymeric monolithic support is proposed for the retention of histidine-containing peptides and their subsequent separation by capillary zone electrophoresis (CZE). Monolithic capillary columns were prepared in fused-silica capillaries of 150 mum inner diameter (ID) by ionizing radiation-initiated in situ polymerization and cross-linking of diethylene glycol dimethacrylate and glycidyl methacrylate, and chemically modified with iminodiacetic acid (IDA) and copper ion. Monolithic microextractors were coupled on-line near the inlet of the separation capillary (fused-silica capillary, 75 mum ID x 28 cm from the microextractor to the detector). Model peptide mixtures of histidine-containing and histidine-noncontaining peptides were assessed. Peptides were released from the sorbent by a 5 mM imidazole solution and then separated by CZE with ultraviolet detection. Relative standard deviation values for migration times and corrected peak areas were found to be lower than 5.8 and 10.5%, respectively. IDA-Cu(II) ion modified monolithic microextractors showed a chromatographic behavior and could be reused at least 25 times. The use of monolithic supports proved to be an advantageous alternative to packed particles for the preparation of microextractors.
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Affiliation(s)
- Nora M Vizioli
- Department of Analytical Chemistry and Physicochemistry, Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
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20
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Lin X, Xue L, Zhang H, Zhu C. Determination of saikosaponins a, c, and d in Bupleurum Chinese DC from different areas by capillary zone electrophoresis. Anal Bioanal Chem 2005; 382:1610-5. [PMID: 16007438 DOI: 10.1007/s00216-005-3371-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2005] [Revised: 05/29/2005] [Accepted: 05/31/2005] [Indexed: 11/26/2022]
Abstract
A fast capillary zone electrophoresis (CZE) method was developed for the determination and separation of saikosaponins a, c, and d in Chinese herbal extracts of Bupleurum Chinese DC from different areas. Detection at 214 nm with a system containing sodium borate buffer and mono-3-phenylcarbamoyl-beta-CD was found to be the most suitable approach for this analysis. Saikosaponins a, c, and d could be easily determined within 8 min. The effect of the concentration of mono-3-phenylcarbamoyl-beta-CD, the concentration of the running buffer and buffer pH value on the migration behavior of the saikosaponins is discussed.
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Affiliation(s)
- Xiuli Lin
- School of Pharmacy, Shandong University, Wen Hua Xi Road 44, Jinan 250012, P. R. China
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21
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Lin CH, Kaneta T. On-line sample concentration techniques in capillary electrophoresis: velocity gradient techniques and sample concentration techniques for biomolecules. Electrophoresis 2005; 25:4058-73. [PMID: 15597415 DOI: 10.1002/elps.200406172] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Methods with a high sensitivity and high separation efficiency are goals in analytical separation techniques. On-line sample concentration techniques in capillary electrophoresis (CE) separations have rapidly grown in popularity over the past few years because they achieve this goal. This review describes the methodology and theory associated with a number of different techniques, including electrokinetic and chromatographic methods. For small molecules, several on-line concentration methods based on velocity gradient techniques are described, in which the electrophoretic velocities of the analyte molecules are manipulated by field amplification, sweeping, and isotachophoretic migration, resulting in the on-line concentration of the analyte zones. In addition, the on-line concentration methods for macromolecules are described, since the techniques used for macromolecules (DNAs and proteins), are different from those for small molecules, with respect to either mechanism or methodology. Recent studies relating to this topic are also discussed, including electrophoretic and chromatographic techniques on capillary or microchip.
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Affiliation(s)
- Cheng-Huang Lin
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
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22
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Gu X, Wang Y, Zhang X. Large-bore particle-entrapped monolithic precolumns prepared by a sol–gel method for on-line peptides trapping and preconcentration in multidimensional liquid chromatography system for proteome analysis. J Chromatogr A 2005; 1072:223-32. [PMID: 15887492 DOI: 10.1016/j.chroma.2005.03.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The present report describes the preparation and characterization of large-bore particle-entrapped monolithic precolumns, which are suitable for incorporation into a two-dimensional liquid chromatography (2D-LC) system for proteome analysis. The fritless precolumns with different inner diameter (i.d.) (320 and 530 microm) were rapidly and successfully prepared by entrapping octadecylsilica (ODS) particles (5 microm, 300 A) prepacked into fused silica capillaries with a sol-gel network, which was formed by hydrolysis and polycondensation of methyltriethoxysilane (MTES). By optimizing the composition of the sol solution, the resulting large-bore monolithic precolumns of 5 mm length allow a flow rate of 20 microL/min loading buffer at a reasonable low back pressure of 25 bar or less and are capable of withstanding up to 300 bar inlet pressure. Scanning electron micrograms of the precolumns profile showed that the evolving sol-gel network joined particles to each other and onto the column wall, and no cracking or shrinkage of the column bed was observed even in 530 microm-i.d. capillary. The performance of the particle-entrapped monolithic precolumns used for preconcentration and desalting of proteolytic digest was evaluated by on-line coupling the large-bore precolumns with a capillary reversed-phase liquid chromatographic (RPLC) column followed by UV detection. The laboratory-made monolithic precolumns with 320 and 530 microm i.d. were characterized by using BSA tryptic digest or peptide standards as the analytes with respect to sample loading capacity, linearity, recovery and reproducibility, etc. The results indicate that the large-bore and short precolumns (5 mm x 320 microm i.d. or 5 mm x 530 microm i.d.) allow sample fast loading at a flow rate of 30 or 60 microL/min. The precolumns also have a mass loading capacity for BSA peptides of about 70 microg and for standard peptides of about 80 microg. Good linear calibration curves (R2 > 0.99) were obtained and the limits of detection (signal-to-noise ratio, S/N = 3) were improved by more than 60-fold and were between 0.53 and 1.32 ng/microL even with a UV absorbance detector. The total recovery was found to be approximately 90-100% for BSA digest and standard peptides. The day-to-day relative standard deviation (RSD) values for recoveries of BSA peptides on a single precolumn ranged from 4.66 to 7.56% and 2.68 to 3.05% for precolumn back pressure, while the column-to-column RSD values were 3.51-6.13% and 1.22-1.26% for recoveries of BSA peptides and precolumn back pressure, respectively. With good precolumn reproducibility, no significant degradation or decrease in precolumn performance was showed even after approximately 150 preconcentration/desorption cycles. The precolumns also proved to be resistant to salt buffer with high concentration and low-pH mobile phase. The large-bore particle-entrapped monolithic precolumns will be further used in a high-throughput 2D-LC array system coupled with tandem matrix assisted laser desorption/ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-TOF-MS) detection for proteome analysis.
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Affiliation(s)
- Xue Gu
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433, China
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Jing P, Kaneta T, Imasaka T. On-Line Concentration of a Protein Using Denaturation by Sodium Dodecyl Sulfate. ANAL SCI 2005; 21:37-42. [PMID: 15675513 DOI: 10.2116/analsci.21.37] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A novel method for the on-column sample stacking of proteins is described. The strategy takes advantage of interactions between protein molecules and sodium dodecyl sulfate (SDS) monomers. A long plug of a protein sample (either acidic or basic) is injected into a capillary filled with a background electrolyte (BGE) containing SDS. When a potential is applied, the proteins interact with SDS monomers in the BGE to form protein-SDS complexes that migrate more slowly than the corresponding uncomplexed protein, resulting in protein stacking. Both acidic and basic proteins migrate at an almost identical electrophoretic velocity after stacking, which indicates that the protein-SDS complexes formed in the BGE zone have a similar charge/mass ratio. The mechanism of stacking was investigated using a sample consisting of a basic protein, lysozyme, and a small molecule, methylene blue. The findings clearly show that two interactions with SDS occur, a stepwise binding interaction between protein molecules and SDS monomers and an interaction in which the small molecules enter into micelles formed by SDS molecules. The method was also applied to the detection of a protein labeled with a fluorescent labeling reagent at trace levels. The labeled protein was detected even under labeling conditions where the labeling efficiency was too low to detect by short-plug injection.
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Affiliation(s)
- Peng Jing
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
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