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Gackowski M, Przybylska A, Kruszewski S, Koba M, Mądra-Gackowska K, Bogacz A. Recent Applications of Capillary Electrophoresis in the Determination of Active Compounds in Medicinal Plants and Pharmaceutical Formulations. Molecules 2021; 26:4141. [PMID: 34299418 PMCID: PMC8307982 DOI: 10.3390/molecules26144141] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/29/2021] [Accepted: 07/05/2021] [Indexed: 11/28/2022] Open
Abstract
The present review summarizes scientific reports from between 2010 and 2019 on the use of capillary electrophoresis to quantify active constituents (i.e., phenolic compounds, coumarins, protoberberines, curcuminoids, iridoid glycosides, alkaloids, triterpene acids) in medicinal plants and herbal formulations. The present literature review is founded on PRISMA guidelines and selection criteria were formulated on the basis of PICOS (Population, Intervention, Comparison, Outcome, Study type). The scrutiny reveals capillary electrophoresis with ultraviolet detection as the most frequently used capillary electromigration technique for the selective separation and quantification of bioactive compounds. For the purpose of improvement of resolution and sensitivity, other detection methods are used (including mass spectrometry), modifiers to the background electrolyte are introduced and different extraction as well as pre-concentration techniques are employed. In conclusion, capillary electrophoresis is a powerful tool and for given applications it is comparable to high performance liquid chromatography. Short time of execution, high efficiency, versatility in separation modes and low consumption of solvents and sample make capillary electrophoresis an attractive and eco-friendly alternative to more expensive methods for the quality control of drugs or raw plant material without any relevant decrease in sensitivity.
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Affiliation(s)
- Marcin Gackowski
- Department of Toxicology and Bromatology, Faculty of Pharmacy, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, A. Jurasza 2 Street, PL–85089 Bydgoszcz, Poland; (A.P.); (M.K.)
| | - Anna Przybylska
- Department of Toxicology and Bromatology, Faculty of Pharmacy, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, A. Jurasza 2 Street, PL–85089 Bydgoszcz, Poland; (A.P.); (M.K.)
| | - Stefan Kruszewski
- Biophysics Department, Faculty of Pharmacy, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, Jagiellońska 13 Street, PL–85067 Bydgoszcz, Poland;
| | - Marcin Koba
- Department of Toxicology and Bromatology, Faculty of Pharmacy, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, A. Jurasza 2 Street, PL–85089 Bydgoszcz, Poland; (A.P.); (M.K.)
| | - Katarzyna Mądra-Gackowska
- Department of Geriatrics, Faculty of Health Sciences, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, Skłodowskiej Curie 9 Street, PL–85094 Bydgoszcz, Poland;
| | - Artur Bogacz
- Department of Otolaryngology and Oncology, Faculty of Medicine, L. Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, Skłodowskiej Curie 9 Street, PL–85094 Bydgoszcz, Poland;
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Şarkaya K, Aşir S, Göktürk I, Ektirici S, Yilmaz F, Yavuz H, Denizli A. Separation of histidine enantiomers by capillary electrochromatography with molecularly imprinted monolithic columns. SEPARATION SCIENCE PLUS 2020. [DOI: 10.1002/sscp.201900101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Koray Şarkaya
- Department of ChemistryHacettepe University Ankara Turkey
| | - Süleyman Aşir
- Department of Materials Science and Nanotechnology EngineeringNear East University Mersin Turkey
| | - Ilgım Göktürk
- Department of ChemistryHacettepe University Ankara Turkey
| | - Sisem Ektirici
- Department of ChemistryHacettepe University Ankara Turkey
| | - Fatma Yilmaz
- Department of Chemistry TechnolgyBolu Abant İzzet Baysal University Bolu Turkey
| | - Handan Yavuz
- Department of ChemistryHacettepe University Ankara Turkey
| | - Adil Denizli
- Department of ChemistryHacettepe University Ankara Turkey
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Şarkaya K, Aşir S, Göktürk I, Yilmaz F, Yavuz H, Denizli A. Electrochromatographic separation of hydrophobic amino acid enantiomers by molecularly imprinted capillary columns. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.02.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Moravcová D, Rantamäki AH, Duša F, Wiedmer SK. Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry. Electrophoresis 2016; 37:880-912. [PMID: 26800083 DOI: 10.1002/elps.201500520] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/18/2015] [Accepted: 12/21/2015] [Indexed: 12/29/2022]
Abstract
Here, we have reviewed separation studies utilizing monolithic capillary columns for separation of compounds preceding MS analysis. The review is divided in two parts according to the used separation method, namely CEC and capillary LC (cLC). Based on our overview, monolithic CEC-MS technique have been more focused on the syntheses of highly specialized and selective separation phase materials for fast and efficient separation of specific types of analytes. In contrast, monolithic cLC-MS is more widely used and is often employed, for instance, in the analysis of oligonucleotides, metabolites, and peptides and proteins in proteomic studies. While poly(styrene-divinylbenzene)-based and silica-based monolithic capillaries found their place in proteomic analyses, the other laboratory-synthesized monoliths still wait for their wider utilization in routine analyses. The development of new monolithic materials will most likely continue due to the demand of more efficient and rapid separation of increasingly complex samples.
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Affiliation(s)
- Dana Moravcová
- Institute of Analytical Chemistry of the CAS, v. v. i, Brno, Czech Republic
| | | | - Filip Duša
- Institute of Analytical Chemistry of the CAS, v. v. i, Brno, Czech Republic
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Chen Z, Bi X, Li J, Tang Y, Fan G, Sun D. Application and optimization of organic-inorganic hybrid monolithic capillary electrochromatography for in vivo cefdinir determination with microdialysis. J Sep Sci 2015; 39:440-9. [DOI: 10.1002/jssc.201500817] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/27/2015] [Accepted: 10/27/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Zhao Chen
- Department of TCM analysis; Guangdong Province Engineering Technology Research Institute of TCM; Guangzhou PR China
| | - Xiaoli Bi
- Department of TCM analysis; Guangdong Province Engineering Technology Research Institute of TCM; Guangzhou PR China
| | - Ji Li
- Department of Pharmaceutical Analysis, School of Pharmacy; Second Military Medical University; Shanghai PR China
- Shanghai Key Laboratory for Pharmaceutical Metabolite Research; Shanghai PR China
| | - Yuanjun Tang
- Department of Pharmaceutical Analysis, School of Pharmacy; Second Military Medical University; Shanghai PR China
- Shanghai Key Laboratory for Pharmaceutical Metabolite Research; Shanghai PR China
| | - Guorong Fan
- Department of Pharmaceutical Analysis, School of Pharmacy; Second Military Medical University; Shanghai PR China
- Shanghai Key Laboratory for Pharmaceutical Metabolite Research; Shanghai PR China
| | - Dongmei Sun
- Department of TCM analysis; Guangdong Province Engineering Technology Research Institute of TCM; Guangzhou PR China
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Chen Z, Huang C, Liu W, Zhang L, Tong P, Zhang L. Simultaneous determination of nucleoside and purine compounds in human urine based on a hydrophobic monolithic column using capillary electrochromatography. Electrophoresis 2015; 36:2727-2735. [DOI: 10.1002/elps.201500194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Zongbao Chen
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
- Key Laboratory of Applied Organic Chemistry, Department of Chemistry; Shangrao Normal University; Shangrao Jiangxi China
| | - Chuanghui Huang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
| | - Wei Liu
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
| | - Lin Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
| | - Ping Tong
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
| | - Lan Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Testing Center; Fuzhou University; Fuzhou Fujian China
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Chen Z, Zhang L, Lu Q, Ye Q, Zhang L. On-line concentration and pressurized capillary electrochromatography analysis of five β-agonists in human urine using a methacrylate monolithic column. Electrophoresis 2015; 36:2720-2726. [DOI: 10.1002/elps.201500229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 06/13/2015] [Accepted: 06/29/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Zongbao Chen
- Key Laboratory of Applied Organic Chemistry, College of Jiangxi Province Department of Chemistry; Shangrao Normal University; Jiangxi P. R. China
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry; Fuzhou University; Fuzhou Fujian, P. R. China
| | - Lan Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry; Fuzhou University; Fuzhou Fujian, P. R. China
| | - Qiaomei Lu
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry; Fuzhou University; Fuzhou Fujian, P. R. China
| | - Qing Ye
- Key Laboratory of Applied Organic Chemistry, College of Jiangxi Province Department of Chemistry; Shangrao Normal University; Jiangxi P. R. China
| | - Lin Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry; Fuzhou University; Fuzhou Fujian, P. R. China
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Posch TN, Pütz M, Martin N, Huhn C. Electromigrative separation techniques in forensic science: combining selectivity, sensitivity, and robustness. Anal Bioanal Chem 2014; 407:23-58. [PMID: 25381613 DOI: 10.1007/s00216-014-8271-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 10/12/2014] [Accepted: 10/14/2014] [Indexed: 01/27/2023]
Abstract
In this review we introduce the advantages and limitations of electromigrative separation techniques in forensic toxicology. We thus present a summary of illustrative studies and our own experience in the field together with established methods from the German Federal Criminal Police Office rather than a complete survey. We focus on the analytical aspects of analytes' physicochemical characteristics (e.g. polarity, stereoisomers) and analytical challenges including matrix tolerance, separation from compounds present in large excess, sample volumes, and orthogonality. For these aspects we want to reveal the specific advantages over more traditional methods. Both detailed studies and profiling and screening studies are taken into account. Care was taken to nearly exclusively document well-validated methods outstanding for the analytical challenge discussed. Special attention was paid to aspects exclusive to electromigrative separation techniques, including the use of the mobility axis, the potential for on-site instrumentation, and the capillary format for immunoassays. The review concludes with an introductory guide to method development for different separation modes, presenting typical buffer systems as starting points for different analyte classes. The objective of this review is to provide an orientation for users in separation science considering using capillary electrophoresis in their laboratory in the future.
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Affiliation(s)
- Tjorben Nils Posch
- Forschungszentrum Jülich GmbH, Central Institute for Engineering, Electronics and Analytics, Analytics ZEA-3, 52425, Jülich, Germany
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D’Orazio G, Rocchi S, Fanali S. Nano-liquid chromatography coupled with mass spectrometry: Separation of sulfonamides employing non-porous core–shell particles. J Chromatogr A 2012; 1255:277-85. [DOI: 10.1016/j.chroma.2012.03.032] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/06/2012] [Accepted: 03/10/2012] [Indexed: 11/25/2022]
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Chen Z, Wang J, Chen D, Fan G, Wu Y. Sodium desoxycholate-assisted capillary electrochromatography with methacrylate ester-based monolithic column on fast separation and determination of coumarin analogs in Angelica dahurica extract. Electrophoresis 2012; 33:2884-91. [PMID: 22930555 DOI: 10.1002/elps.201200120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 05/11/2012] [Accepted: 05/14/2012] [Indexed: 11/11/2022]
Abstract
A rapid and sensitive CEC method with methacrylate ester-based monolithic column has been developed for separation and determination of five coumarins (byakangelicin, oxypeucedanin hydrate, xanthotoxol, 5-hydroxy-8-methoxypsoralen and bergapten) in Angelica dahurica extract. Surfactant sodium desoxycholate (SDC) was introduced into the mobile phase as the pseudostationary to dynamically increase the selectivity of analytes instead of increasing the hydrophobicity of stationary phase. In addition, other factors, pH of phosphate buffer, ACN content and applied voltage, for instance, have also an obvious effect on the resolution but little on the retention time. Satisfactory separation of these five coumarins was achieved within 6 min under a 30:70 v/v ACN-buffer containing 20 mM sodium dihydrogen phosphate (NaH(2) PO(4) ) and 0.25 mM SDC at pH 2.51. The RSDs of intraday and interday for relative peak areas were less than 3.0% and 4.7%, respectively; and the recoveries were between 87.5% and 95.0%. The LODs were lower than 0.15 μg/mL and the LOQs were lower than 0.30 μg/mL, respectively, while calibration curves showed a good linearity (r(2) > 0.9979). Finally, five target coumarins from the crude extracts of A. dahurica were separated, purified, and concentrated by D-101 macroporous resin, and were successfully separated and quantitatively determined within 6 min.
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Affiliation(s)
- Zhao Chen
- Department of Pharmaceutical Analysis, Second Military Medical University, Shanghai, People's Republic of China. cz04101103@ hotmail.com
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Chen Z, Cai Y, Zhang L, Zhang L. Capillary electrochromatography of three β2-agonists in human urine using a lauryl methacrylate-based monolithic column. J Sep Sci 2012; 35:1138-45. [DOI: 10.1002/jssc.201101005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Yan Cai
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety,; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety,; Department of Chemistry; Fuzhou University; Fuzhou; Fujian; China
| | - Lin Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety,; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety,; Department of Chemistry; Fuzhou University; Fuzhou; Fujian; China
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D’Orazio G, Fanali S. C18 silica packed capillary columns with monolithic frits prepared with UV light emitting diode: Usefulness in nano-liquid chromatography and capillary electrochromatography. J Chromatogr A 2012; 1232:176-82. [DOI: 10.1016/j.chroma.2011.11.056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 11/24/2011] [Accepted: 11/28/2011] [Indexed: 11/26/2022]
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Nischang I, Höltzel A, Tallarek U. Electrochromatographic retention of peptides on strong cation-exchange stationary phases. Electrophoresis 2010; 31:933-43. [DOI: 10.1002/elps.200900549] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Nischang I, Tallarek U. Inherent peak compression of charged analytes in electrochromatography. J Sep Sci 2010; 32:3157-68. [PMID: 19746396 DOI: 10.1002/jssc.200900436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This work resolves peak compression of charged analytes in CEC with strong cation-exchange stationary phase particles. By combining electrochromatographic peak shape analysis with the results of numerical simulations and confocal laser scanning microscopy in the packed capillaries, we identify electrical field-induced concentration polarization as the key physical phenomenon responsible for the inherent existence of local electrical field gradients on the scale of an individual support particle. Consequently, positive and negative field gradients exist between and inside the particles along the whole packing. Their intensity depends on the particles cation-selectivity (governed by the particles volume charge density and the mobile phase ionic strength) and the applied field strength. The interplay of these local field gradients with the analytes retention (intraparticle adsorption) determines whether fronting, tailing, or spiked analyte peaks are observed, and it provides a mechanism by which strongly retained analytes can be eluted over long distances with little zone dispersion. Our analysis explains the "anomalous" peak compression effects with strong cation-exchange particles, which have been reported more than a decade ago (Smith, N. W., Evans, M. B., Chromatographia 1995, 41, 197-203) and since then remained largely unresolved.
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Affiliation(s)
- Ivo Nischang
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
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Li LS, Wang Y, James Young D, Ng SC, Tan TTY. Monodispersed submicron porous silica particles functionalized with CD derivatives for chiral CEC. Electrophoresis 2010; 31:378-87. [DOI: 10.1002/elps.200900318] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lu M, Feng Q, Lu Q, Cai Z, Zhang L, Chen G. Preparation and evaluation of the highly cross-linked poly(1-hexadecane-co-trimethylolpropane trimethacrylate) monolithic column for capillary electrochromatography. Electrophoresis 2009; 30:3540-7. [DOI: 10.1002/elps.200900018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chen D, Wang J, Jiang Y, Zhou T, Fan G, Wu Y. Separation and determination of coumarins in Fructus cnidii extracts by pressurized capillary electrochromatography using a packed column with a monolithic outlet frit. J Pharm Biomed Anal 2009; 50:695-702. [PMID: 19608371 DOI: 10.1016/j.jpba.2009.05.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 04/30/2009] [Accepted: 05/22/2009] [Indexed: 11/18/2022]
Abstract
The pressurized capillary electrochromatography (pCEC) was utilized for the separation and determination of coumarins in Fructus cnidii extracts from 12 different regions. After a thorough study of analytical parameters such as acetonitrile content of the mobile phase, the concentration and pH of the buffer, and the applied voltage, a methodology was proposed to separate and determine six coumarins of F. cnidii extracts in less than 15 min. The experiments were performed in an in-house packed column with a monolithic outlet frit under the optimal conditions: pH 4.0 ammonium acetate buffer at 10 mM containing 50% acetonitrile at -6kV applied voltage. The calibration curves were linear in the range of 10.0-100.0 microg/mL for bergapten, 20.0-200.0 microg/mL for imperatorin, 5.0-400.0 microg/mL for osthole, 10.0-100.0 microg/mL for 2'-acetylangelicin, 10.0-200.0 microg/mL for oroselone, and 10.0-200.0 microg/mL for O-acetylcolumbianetin. The correlation coefficients were between 0.9967 and 0.9995. With this pCEC system, fingerprints of F. cnidii extracts were preliminarily established to distinguish three types of coumarins by characteristic peaks, and the quality of various sources of raw materials was evaluated by determining the contents of six coumarins.
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Affiliation(s)
- Danxia Chen
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No. 325 Guohe Road, Shanghai 200433, PR China
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Li H, Liu X, Niu W, Zhu S, Fan L, Shi L, Xu G. CEC with tris(2,2′-bipyridyl) ruthenium(II) electrochemiluminescent detection. Electrophoresis 2008; 29:4475-81. [DOI: 10.1002/elps.200800088] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mistry K, Grinberg N. Separation of Peptides and Proteins by Capillary Electrochromatography. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120030601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Kavita Mistry
- a Analytical Research , Merck & Co., Inc. , RY818‐C208, P.O. Box 2000, Rahway , New Jersey , 07065 , USA
| | - Nelu Grinberg
- a Analytical Research , Merck & Co., Inc. , RY818‐C208, P.O. Box 2000, Rahway , New Jersey , 07065 , USA
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Li G, Zhou X, Wang Y, Krull IS, Mistry K, Grinberg N, Cortes H. The Analysis of Synthetic Organic, Neutral Polymers Using Nonaqueous Capillary Gel Electrophoresis (NACGE). J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120030171] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Guodong Li
- a Department of Chemistry , Northeastern University , 102 Hurtig Building, 360 Huntington Avenue, Boston , Massachusetts , 02115 , USA
| | - Xiaojuan Zhou
- a Department of Chemistry , Northeastern University , 102 Hurtig Building, 360 Huntington Avenue, Boston , Massachusetts , 02115 , USA
| | - Yonghui Wang
- a Department of Chemistry , Northeastern University , 102 Hurtig Building, 360 Huntington Avenue, Boston , Massachusetts , 02115 , USA
| | - Ira S. Krull
- a Department of Chemistry , Northeastern University , 102 Hurtig Building, 360 Huntington Avenue, Boston , Massachusetts , 02115 , USA
| | - Kavita Mistry
- b Analytical Research Department , Merck & Co., Inc. , Rahway , New Jersey , USA
| | - Nelu Grinberg
- b Analytical Research Department , Merck & Co., Inc. , Rahway , New Jersey , USA
| | - Hernan Cortes
- c Project Leader, Organic Analysis Group , Dow Chemical Company, Analytical Sciences , Midland , Michigan , USA
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Yang Y, Boysen RI, Matyska MT, Pesek JJ, Hearn MTW. Open-Tubular Capillary Electrochromatography Coupled with Electrospray Ionization Mass Spectrometry for Peptide Analysis. Anal Chem 2007; 79:4942-9. [PMID: 17539599 DOI: 10.1021/ac0622633] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, the open-tubular electrochromatographic (OT-CEC) migration behavior of various peptides has been characterized using etched and chemically (n-octadecyl- and cholesterol-) modified capillaries, interfaced to an electrospray ionization mass spectrometer through a sheath liquid configuration. The stationary phases were fabricated by etching the inner wall of the fused-silica capillary and then chemically modifying the new surface through a silanization/hydrosilation reaction. Unlike some other OT-CEC stationary-phase preparation methods, leaching of the immobilized stationary phase and subsequent contamination of the electrospray ion source was largely avoided with this novel surface modification technology. The influence of the immobilized organic phases and those of the buffer electrolytes (pH, the type and content of organic solvent) on the retention and separation of the selected peptides was investigated. Significant peptide retention was found even at very low pH with both types of stationary phases, under conditions whereby the electrophoretic migration dominated the separation process. Due to the effective coverage of the etched surface by a silanization/hydrosilation reaction, adverse adsorption of charged analytes onto the capillary wall was minimized. As a result, very efficient and highly reproducible peptide separations were achieved over a broad pH range. Moreover, peptide-specific multizoning effects were observed. The origin of this novel phenomenon was explored. Compared to capillary electrophoresis electrospray ionization mass spectrometry system, much higher detection sensitivity could be obtained, since a larger amount of sample could be injected and stacked at the head of the open-tubular capillary column without deteriorating the separation performance. On the basis of these observations, these procedures have been adapted to allow the analysis of tryptic peptides generated from proteins.
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Affiliation(s)
- Yuanzhong Yang
- Australian Research Council Special Research Centre for Green Chemistry, Clayton, Victoria, 3800, Australia
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Barceló-Barrachina E, Moyano E, Puignou L, Galceran MT. CEC separation of heterocyclic amines using methacrylate monolithic columns. Electrophoresis 2007; 28:1704-13. [PMID: 17465421 DOI: 10.1002/elps.200600356] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Two methacrylate-based monolithic columns, one with a negatively charged group (sulfonic group) and another with a new monomer N,N-dimethylamino ethyl acrylate (DMAEA), were prepared and tested for the separation of basic compounds by CEC. This new monolithic stationary phase was prepared by the in situ polymerization of DMAEA with butyl methacrylate and ethylene dimethacrylate, using a ternary porogenic solvent consisting of water, 1-propanol and 1,4-butanediol. The performance of this column was evaluated by means of the analysis of a family of heterocyclic amines. Separation conditions such as pH, amount of organic modifier, ionic strength and elution mode (normal or counterdirectional flow) were studied. At the optimal running electrolyte composition, and using the counterdirectional mode, symmetrical electrochromatographic peaks were obtained, with the number of theoretical plates up to 30,000 and a good resolution between closely related peaks. The 2-acrylamido-2-methyl-1-propane-sulfonic acid column was used for CEC-MS, taking advantage of the compatibility of its elution mode (normal flow) with the MS coupling.
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Abstract
This review is concerned with the phenomenological fluid dynamics in capillary and chip electrochromatography (EC) using high-surface-area random porous media as stationary phases. Specifically, the pore space morphology of packed beds and monoliths is analyzed with respect to the nonuniformity of local and macroscopic EOF, as well as the achievable separation efficiency. It is first pointed out that the pore-level velocity profile of EOF through packed beds and monoliths is generally nonuniform. This contrasts with the plug-like EOF profile in a single homogeneous channel and is caused by a nonuniform distribution of the local electrical field strength in porous media due to the continuously converging and diverging pores. Wall effects of geometrical and electrokinetic nature form another origin for EOF nonuniformities in packed beds which are caused by packing hard particles against a hard wall with different zeta potential. The influence of the resulting, systematic porosity fluctuations close to the confining wall over a distance of a few particle diameters becomes aggravated at low column-to-particle diameter ratio. Due to the hierarchical structure of the pore space in packed beds and silica-based monoliths which are characterized by discrete intraparticle (intraskeleton) mesoporous and interparticle (interskeleton) macroporous spatial domains, charge-selective transport prevails within the porous particles and the monolith skeleton under most general conditions. It forms the basis for electrical field-induced concentration polarization (CP). Simultaneously, a finite and -- depending on morphology -- often significant perfusive EOF is realized in these hierarchically structured materials. The data collected in this review show that the existence of CP and its relative intensity compared to perfusive EOF form fundamental ingredients which tune the fluid dynamics in EC employing monoliths and packed beds as stationary phases. This addresses the (electro)hydrodynamics, associated hydrodynamic dispersion, as well as the migration and retention of charged analytes.
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Affiliation(s)
- Ivo Nischang
- Institut für Verfahrenstechnik, Otto-von-Guericke-Universität, Magdeburg, Germany
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25
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Zheng J, Rizvi SAA, Shamsi SA, Hou J. Photopolymerized Sol‐Gel Monolithic Column for Capillary Electrochromatography (CEC) and CEC Coupled to Atmospheric Pressure Photoionization Mass Spectrometry. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070601034238] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Jie Zheng
- a Department of Chemistry , Center of Biotechnology and Drug Design, Georgia State University , Atlanta, Georgia, USA
| | - Syed A. A. Rizvi
- a Department of Chemistry , Center of Biotechnology and Drug Design, Georgia State University , Atlanta, Georgia, USA
| | - Shahab A. Shamsi
- a Department of Chemistry , Center of Biotechnology and Drug Design, Georgia State University , Atlanta, Georgia, USA
| | - Jingguo Hou
- b Department of Clinical Sciences and Administration , College of Pharmacy, University of Houston, Texas Medical Center , Houston, Texas, USA
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26
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Natishan TK. Recent Progress in the Analysis of Pharmaceuticals by Capillary Electrophoresis. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-200053014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Theresa K. Natishan
- a Merck & Co., Inc. , Merck Research Laboratories, Analytical Research , Rahway, New Jersey, USA
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27
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Patton WF, Panchagnula V, Rockney E, Krull IS. Taking a Walk on the Wild Side with Planar Electrochromatography and Thin‐Layer Electrophoresis: Of Peptides, Proteins, and Proteomics. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070600574978] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Wayne F. Patton
- a PerkinElmer Life and Analytical Sciences, Life Sciences Division , Boston, Massachusetts, USA
| | | | - Erin Rockney
- a PerkinElmer Life and Analytical Sciences, Life Sciences Division , Boston, Massachusetts, USA
| | - Ira S. Krull
- b Department of Chemistry and Chemical Biology , Northeastern University , Boston, Massachusetts, USA
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28
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Okamoto Y, Ikawa Y, Kitagawa F, Otsuka K. Preparation of fritless capillary using avidin immobilized magnetic particles for electrochromatographic chiral separation. J Chromatogr A 2007; 1143:264-9. [PMID: 17240386 DOI: 10.1016/j.chroma.2007.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 12/26/2006] [Accepted: 01/02/2007] [Indexed: 10/23/2022]
Abstract
In capillary electrochromatography (CEC), magnetic particles (MPs) were packed in a fused silica capillary by using the magnetic field to be retained without frits. For a chiral CEC separation, avidin was immobilized onto the surface of the MPs (AVI-MPs) as a stationary phase by using the physical adsorption technique. The injected AVI-MPs into the capillary were stably captured with the magnet (surface magnetic flux density, 250 mT) under the separation voltage of 10 kV (190 V/cm). By employing the fritless AVI-MPs packed capillary, the chiral separation of ketoprofen was successfully attained with the packing length of only 5 cm. Effects of the modification condition of avidin, pH of background solution, and the packing length on the enantioseparation were also investigated. Under the optimal condition, furthermore, the repeatability for the retention time of ketoprofen was better than 1.5% in the relative standard deviation and the capillary-to-capillary reproducibility was also acceptable in the prepared fritless capillaries.
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Affiliation(s)
- Yukihiro Okamoto
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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29
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Hlushkou D, Khirevich S, Apanasovich V, Seidel-Morgenstern A, Tallarek U. Pore-Scale Dispersion in Electrokinetic Flow through a Random Sphere Packing. Anal Chem 2006; 79:113-21. [PMID: 17194128 DOI: 10.1021/ac061168r] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The three-dimensional velocity field and corresponding hydrodynamic dispersion in electrokinetic flow through a random bulk packing of impermeable, nonconducting spheres are studied by quantitative numerical analysis. First, a fixed bed with interparticle porosity of 0.38 is generated using a parallel collective-rearrangement algorithm. Then, the interparticle velocity field is calculated using the lattice-Boltzmann (LB) method, and a random-walk particle-tracking method is finally employed to model advection-diffusion of an inert tracer in the LB velocity field. We demonstrate that the pore-scale velocity profile for electroosmotic flow (EOF) is nonuniform even under most ideal conditions, including a negligible thickness of the electrical double layer compared to the mean pore size, a uniform distribution of the electrokinetic potential at the solid-liquid interface, and the absence of applied pressure gradients. This EOF dynamics is caused by a nonuniform distribution of the local electrical field strength in the sphere packing and engenders significant hydrodynamic dispersion compared to pluglike EOF through a single straight channel. Both transient and asymptotic dispersion behaviors are analyzed for EOF in the context of packing microstructure and are compared to pressure-driven flow in dependence of the average velocity through the bed. A better hydrodynamic performance of EOF originates in a still much smaller amplitude of velocity fluctuations on a mesoscopic scale (covering several particle diameters), as well as on the microscopic scale of an individual pore.
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Affiliation(s)
- Dzmitry Hlushkou
- Institut für Verfahrenstechnik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
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30
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Yuan W, Zhao GF, Dong XY, Sun Y. High-capacity purification of hen egg-white proteins by ion-exchange electrochromatography with an oscillatory transverse electric field. J Sep Sci 2006; 29:2383-9. [PMID: 17120823 DOI: 10.1002/jssc.200600149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ion-exchange electrochromatography with an oscillatory electric field perpendicular to the mobile-phase flow driven by pressure (pIEEC) was used to separate hen egg-white (HEW) proteins. The results were compared with those of normal ion-exchange chromatography (IEC). The column was designed as three-compartment rectangular column of 2-mL with dimensions (length x width x depth) of 40 x 10 x 5 mm(3) and the electric field was applied across the direction of column width. Q Sepharose FF was packed into the central compartment as the chromatographic bed. It was confirmed that the dynamic binding capacity (DBC) of different proteins (ovotransferrin and ovalbumin) in the HEW solution increased 2.3 times when an oscillatory electric current of 30 mA at 1/20 Hz was applied in the transverse column direction. Then, the HEW proteins were separated by the pIEEC at loading amounts 2.3-fold higher than those by the IEC. When the feedstock of about one-third of the DBC was applied to the columns (i.e., 7 mL for the pIEEC and 3 mL for the IEC), similar separation efficiencies of the two chromatographic modes were achieved. Both the recovery yield and purity reached 73% to over 90%. The results indicate that the pIEEC is promising for high-capacity purification of proteins.
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Affiliation(s)
- Wei Yuan
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
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31
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Roman GT, Carroll S, McDaniel K, Culbertson CT. Micellar electrokinetic chromatography of fluorescently labeled proteins on poly(dimethylsiloxane)-based microchips. Electrophoresis 2006; 27:2933-9. [PMID: 16721904 DOI: 10.1002/elps.200500795] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
MEKC of standard proteins was investigated on PDMS microfluidic devices. Standard proteins were labeled with AlexaFluor(R) 488 carboxylic acid tetrafluorophenyl ester and filtered through a size-exclusion column to remove any small peptides and unreacted label. High-efficiency MEKC separations of these standard proteins were performed using a buffer consisting of 10 mM sodium tetraborate, 25 mM SDS, and 20% v/v ACN. A separation of BSA using this buffer in a 3.0 cm long channel generated a peak with a plate height of 0.38 microm in <20 s. Additional fast separations of myoglobin, alpha-lactalbumin, lysozyme, and cytochrome c also yielded peaks with plate heights ranging from 0.54 to 0.72 microm. All proteins migrated with respect to their individual pIs. To improve the separations, we used a PDMS serpentine chip with tapered turns and a separation distance of 25 cm. The number of plates generated increased linearly with increasing separation distance on the extended separation channel chips; however, the resolution reached an asymptotic value after about 7 cm. This limited the peak capacity of the separation technique to 10-12.
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Affiliation(s)
- Gregory T Roman
- Department of Chemistry, Kansas State University, Manhattan, KS 66506, USA
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32
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Nischang I, Spannmann K, Tallarek U. Key to Analyte Migration and Retention in Electrochromatography. Anal Chem 2006; 78:3601-8. [PMID: 16737213 DOI: 10.1021/ac052133e] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This work identifies electrical field-induced concentration polarization (CP) as a key physical mechanism influencing the retention behavior of charged analytes in electrochromatography with fixed beds of porous adsorbent particles. Due to an insufficient screening of intraparticle surface charge, under most general conditions the porous (permeable) particles become charge-selective. CP is caused by coupled mass and charge transport normal to the charge-selective external surface of the permeable particles, which leads to concentration gradients of ionic species in the adjoining interparticle electrolyte solution. Cation-exchange (cation-selective) particles were employed to investigate the influence of applied voltage on the retention factor of counterionic, i.e., positively charged, analytes. It is demonstrated by macroscopic retention data and microscopic studies resolving the CP phenomenon on a particle scale that the dependence of CP on electrical field and mobile-phase ionic strengths is directly reflected in concomitant changes of analyte retention. The CP zones that develop at the interface between interparticle and intraparticle pore space are recognized by charged, but not electroneutral analytes while entering or leaving the particles. The intensity of these convective-diffusion boundary layers (CP zones) depends on the applied field strength and charge selectivity of a particle. Thus, it is the charge-selective transport between the interparticle and intraparticle pore space in packed beds that prevails under typical experimental conditions in electrochromatography and that forms the physical basis for a general electrical field dependence of the retention factor of charged analytes.
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Affiliation(s)
- Ivo Nischang
- Institut für Verfahrenstechnik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
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33
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Tan GM, Dong XY, Sun Y. Oscillatory transverse electric field enhances protein resolution and capacity of size-exclusion chromatography. J Sep Sci 2006; 29:684-90. [PMID: 16605088 DOI: 10.1002/jssc.200500354] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein separations by a novel size-exclusion electrochromatography (SEEC) are presented. The present SEEC, denoted as pSEEC, was established with an oscillatory low-voltage electric field perpendicular to the mobile-phase streamline. Retention experiments with different proteins indicated that the influence of electric field strength on the partition coefficient is different for different proteins as well as for the same protein under different mobile-phase conditions. These results of protein retention led to the experimental design of protein separations with binary mixtures of BSA and immunoglobulin G (IgG), myoglobin (Myo) and lysozyme (Lys), as well as ovalbumin (Oval) and Myo. The separation results for the binary protein systems sufficiently exhibited the applicability of the pSEEC for various separations in terms of their molecular weights (MWs) as well as pIs. For example, it was possible to separate the gel-excluded proteins (BSA/IgG) as well as gel-permeable and similar-molecular-weight proteins (Myo/Lys) by the pSEEC. Moreover, in the cases of Oval/ Myo, which could be partially separated by size-exclusion chromatography, the use of the pSEEC greatly improved the resolution and the separation became possible at high sample loading. The results indicate that the pSEEC technology is promising for preparative protein separations.
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Affiliation(s)
- Guo-Min Tan
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
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34
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Zhang L, Yin X, Fang Z. Negative pressure pinched sample injection for microchip-based electrophoresis. LAB ON A CHIP 2006; 6:258-64. [PMID: 16450036 DOI: 10.1039/b511924c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A simple method for injecting well-defined non-biased sample plugs into the separation channel of a microfluidic chip-based capillary electrophoresis system was developed by a combination of flows generated by negative pressure, electrokinetic and hydrostatic forces. This was achieved by using only a single syringe pump and a single voltage supply at constant voltage. In the loading step, a partial vacuum in the headspace of a sealed sample waste reservoir was produced using a syringe pump equipped with a 3-way valve. Almost instantaneously, sample was drawn from the sample reservoir across the injection intersection to the sample waste reservoir by negative pressure. Simultaneously, buffer flow from the remaining two buffer reservoirs pinched the sample flow to form a well-defined sample plug at the channel intersection. In the subsequent separation stage, the vacuum in headspace of the sample waste reservoir was released to terminate all flows generated by negative pressure, and the sample plug at the channel intersection was electrokinetically injected into the separation channel under the potential applied along the separation channel. The liquid levels of the four reservoirs were optimized to prevent sample leakage during the separation stage. The approach considerably simplified the operations and equipment for pinched injection in chip-based CE, and improved the throughput. Migration time precisions of 3.3 and 1.5% RSD for rhodamine123 (Rh123) and fluorescein sodium (Flu) in the separation of a mixture of Flu and Rh123 were obtained for 56 consecutive determinations with peak height precisions of 6.2% and 4.4% RSD for Rh123 and Flu, respectively.
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Affiliation(s)
- Lei Zhang
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, 310027, Hangzhou, China
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35
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Mangelings D, Discry J, Maftouh M, Massart DL, Vander Heyden Y. Strategy for the chiral separation of non-acidic pharmaceuticals using capillary electrochromatography. Electrophoresis 2005; 26:3930-41. [PMID: 16167306 DOI: 10.1002/elps.200500079] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In completion of an earlier defined generic chiral screening approach, a generic separation strategy for basic, bifunctional, and neutral compounds was proposed and evaluated. This strategy adds to a previously defined strategy for acidic compounds. The screening experiment of the actual strategy used a mobile phase of 5 mM phosphate buffer pH 11.5/ACN (30/70 v/v), a temperature of 25 degrees C, and a voltage of 15 kV. The selected chiral stationary phases were Chiralpak AD-RH, Chiralcel OD-RH, Chiralcel OJ-RH, and Chiralpak AS-RH, all based on polysaccharide selectors. It was seen that 31 out of 48 test compounds were partially or baseline-resolved under screening conditions. After execution of the optimization steps of the strategy, this number increased to 41, with a total of 21 baseline-separated compounds. Combined with the results obtained from the acidic test set examined in the earlier defined strategy, of all tested compounds 82.5% showed enantioselectivity and 49.2% could be baseline-separated.
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Affiliation(s)
- Debby Mangelings
- Department of Pharmaceutical and Biomedical Analysis, Pharmaceutical Institute, Vrije Universiteit Brussel-VUB, Brussels, Belgium
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36
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Valette JC, Demesmay C, Rocca JL, Verdon E. Potential Use of an Aminopropyl Stationary Phase in Hydrophilic Interaction Capillary Electrochromatography. Application to Tetracycline Antibiotics. Chromatographia 2005. [DOI: 10.1365/s10337-005-0621-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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37
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Fu LM, Yang RJ, Lin CH, Chien YS. A novel microfluidic mixer utilizing electrokinetic driving forces under low switching frequency. Electrophoresis 2005; 26:1814-24. [PMID: 15754383 DOI: 10.1002/elps.200410222] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper presents a novel technique in which low-frequency periodic electrokinetic driving forces are utilized to mix electrolytic fluid samples rapidly and efficiently in a double-T-form microfluidic mixer. Without using any additional equipment to induce flow perturbations, only a single high-voltage power source is required for simultaneously driving and mixing the sample fluids which results in a simple and low-cost system for the mixing purpose. The effectiveness of the mixer as a function of the applied electric field and the periodic switching frequency is characterized by the intensity distribution calculated downstream from the mixing zone. The present numerical and experimental results confirm that the proposed double-T-form micromixer has excellent mixing capabilities. The mixing efficiency can be as high as 95% within a mixing length of 1000 microm downstream from the secondary T-junction when a 100 V/cm driving electric field strength and a 2 Hz periodic switching frequency are applied. The results reveal that the optimal switching frequency depends upon the magnitude of the main applied electrical field. The rapid double-T-form microfluidic mixer using the periodic driving voltage switching model proposed in this study has considerable potential for use in lab-on-a-chip systems.
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Affiliation(s)
- Lung-Ming Fu
- Graduate Institute of Materials Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan
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38
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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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39
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Czerwenka C, Lindner W. Stereoselective peptide analysis. Anal Bioanal Chem 2005; 382:599-638. [PMID: 15856198 DOI: 10.1007/s00216-005-3091-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 01/14/2005] [Accepted: 01/19/2005] [Indexed: 10/25/2022]
Abstract
The stereochemistry of a peptide determines its spatial features and can profoundly influence its chemical properties and biological activity. Thus, the analysis of the stereochemical properties of a peptide is an important aspect of its characterisation. For such investigations a "selector" that engages in stereoselective interactions with the peptide analytes is often used. A substantiated knowledge of the underlying molecular recognition mechanism will therefore be helpful in understanding existing and developing new stereoselective analysis systems. After a short introduction concerning the fundamentals of peptide stereoisomers and their biological implications, the stereoselective peptide analysis methods described in the literature are comprehensively reviewed. The characteristics and applications of the employed methods based on various techniques including chromatography (pressure- and electrokinetically driven), capillary electrophoresis, nuclear magnetic resonance spectroscopy and mass spectrometry are discussed. The various selectors that have been utilised to discriminate peptide enantiomers and/or diastereomers are described concurrently. The review concludes with an overview of combinations and comparisons of techniques that have been applied to the analysis of peptide stereoisomers and constitute a trend for further developments.
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Affiliation(s)
- Christoph Czerwenka
- Institute of Analytical Chemistry, University of Vienna, Währingerstrasse 38, 1090 Wien, Austria
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40
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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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41
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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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42
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Tallarek U, Leinweber FC, Nischang I. Perspective on concentration polarization effects in electrochromatographic separations. Electrophoresis 2005; 26:391-404. [PMID: 15657887 DOI: 10.1002/elps.200406167] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This work illustrates the appearance and electrohydrodynamic consequences of concentration polarization in the particulate and monolithic fixed beds used in capillary electrochromatography and related electrical-field assisted processes. Key property of most porous materials is the co-existence of bulk, quasi-electroneutral macroporous regions and mesoporous compartments which are ion-permselective (due to electrical double-layer overlap) causing different transport numbers for co-ionic and counterionic species, e.g., background electrolyte components, or the analytes. For a cathodic electroosmotic flow the (cation) permselectivity, together with diffusive and electrokinetic transport induces depleted and enriched concentration polarization zones at the anodic and cathodic interfaces, respectively, in dependence of the mobile phase ionic strength and applied electrical fields. At high field strength a secondary, nonequilibrium electrical double layer may be created in the depleted concentration polarization zones of a material stimulating electroosmosis of the second kind. The potential of this induced-charge electroosmosis with respect to nonlinear flow velocities and electrokinetic instability mixing (basically destroying the concentration polarization zones) is analyzed in view of the pore space morphology in random-close packings of spherical-shaped, porous particles and hierarchically structured monoliths. Possible applications based on a fine-tuning of the illustrated effects emerge for microfluidic pumping and mixing, or the intensification of sample recovery in adsorption processes. With this perspective we want to focus the attention on concentration polarization in electrochromatographic systems by presenting and discussing original data acquired on relevant microscopic as well as macroscopic scales, and point towards the importance of related effects in colloid and membrane science.*
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Affiliation(s)
- Ulrich Tallarek
- Institut für Verfahrenstechnik, Otto-von-Guericke-Universität, Magdeburg, Germany.
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43
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Abstract
Electrochromatography (EC) in microfluidic chips is emerging as an attractive alternative to capillary electrophoresis (CE) for on-chip separations. This review summarizes recent developments in the rapidly growing area of chip electrochromatography with a focus on "column" technologies. Relevant achievements are summarized according to the types of stationary phase used for the separations including open channels, microfabricated structures, and channels packed with beads or containing a porous monolith. The advantages and disadvantages of each, as well as practical aspects of their application, are discussed. The analytical performance of these devices is demonstrated with separations involving various families of compounds mostly in the reversed-phase chromatographic mode.
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Affiliation(s)
- Timothy B Stachowiak
- Department of Chemical Engineering, University of California, Berkeley, CA 94720-1460, USA
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44
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Abstract
In this review the literature on the application of capillary electrochromatography (CEC) for size-based separations of macromolecules is summarized. Opportunities and limitations of CEC specially related to the size-exclusion mode (SEEC) are indicated. Applications with synthetic polymer samples as well as with biomacromolecules (polysaccharides, proteins) are shown. The prospects for a further development and application of SEEC are discussed.
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Affiliation(s)
- Wim Th Kok
- Polymer-Analysis Group, Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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45
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Kahle V, Kost'ál V, Zeisbergerová M. Sample injection in capillary electrochromatography by heart-cut technique. J Chromatogr A 2004; 1044:259-65. [PMID: 15354446 DOI: 10.1016/j.chroma.2004.04.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The splitter working in heart-cut regime was used for sample injection in capillary electrochromatography. The principle was implemented in an automated microgradient system allowing to inject from microlitre down to nanolitre volumes with high repeatability and minimal extra-column band broadening. The apparatus is able to deliver discrete volumes of liquids at a preset volumetric flow rate and to stop and restore the flow at any moment. This brings a high degree of liquid manipulation flexibility. An extremely low split ratio is sufficient during the analysis, which saves mobile phase consumption substantially. The key parameters influencing the function of the heart-cut splitter were characterised. The function of the apparatus was demonstrated under isocratic, preconcentration and gradient capillary electrochromatography separation conditions. In all cases the statistic evaluation of the main parameters was performed, showing that high repeatability of retention times, peak heights and areas was achieved.
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Affiliation(s)
- Vladislav Kahle
- Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Veverí 97, 611 42 Brno, Czech Republic.
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Pucci V, Raggi MA, Svec F, Fréchet JMJ. Monolithic columns with a gradient of functionalities prepared via photoinitiated grafting for separations using capillary electrochromatography. J Sep Sci 2004; 27:779-88. [PMID: 15354555 DOI: 10.1002/jssc.200401828] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Stationary phases for capillary electrochromatography with a longitudinal gradient of functionalities have been prepared via photoinitiated grafting of polymer chains onto the pore surface of a porous polymer monolith. In order to achieve the desired retention and electroosmotic flow, the hydrophobic poly(butyl methacrylate-co-ethylene dimethacrylate) monolith with optimized porous properties was grafted with a layer of ionizable polymer, poly(2-acrylamido-2-methyl-1-propanesulfonic acid). A moving shutter and a neutral density filter were used to control the dose of UV light received at different locations along the monolith in order to create the longitudinal gradient of functionalities. Formation of the desired gradients was confirmed using electron probe microanalysis of different locations along the column. The preparation technique significantly affects performance in the CEC mode as demonstrated on the separations of a model mixture using columns both with homogeneous distribution of grafts and with a gradient of functionality. Columns grafted with the gradient of functionalities were found superior to those functionalized uniformly. A comparison of the performance of the gradient column with another containing evenly distributed functionalities showed the performance benefits of the "gradient" column.
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Affiliation(s)
- Vincenzo Pucci
- Material Sciences Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 97420-8139, USA
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Abstract
A review is presented on the current state of the art and future trends in the development of sol-gel stationary phases for capillary electrochromatography (CEC). The design and synthesis of stationary phases with prescribed chromatographic and surface charge properties represent challenging tasks in contemporary CEC research. Further developments in CEC as a high-efficiency liquid-phase separation technique will greatly depend on new breakthroughs in the area of stationary phase development. The requirements imposed on CEC stationary phase performance are significantly more demanding compared with those for HPLC. The design of CEC stationary phase must take into consideration the structural characteristics that will provide not only the selective solute/stationary phase interactions leading to chromatographic separations but also the surface charge properties that determine the magnitude and direction of the electroosmotic flow responsible for the mobile phase movement through the CEC column. Therefore, the stationary phase technology in CEC presents a more complex problem than in conventional chromatographic techniques. Different approaches to stationary phase development have been reported in contemporary CEC literature. The sol-gel approach represents a promising direction in this important research. It is applicable to the preparation of CEC stationary phases in different formats: surface coatings, micro/submicro particles, and monolithic beds. Besides, in the sol-gel approach, appropriate sol-gel precursors and other building blocks can be selected to create a stationary phase with desired structural and surface properties. One remarkable advantage of the sol-gel approach is the mild thermal conditions under which the stationary phase synthesis can be carried out (typically at room temperature). It also provides an effective pathway to integrating the advantageous properties of organic and inorganic material systems, and thereby enhancing and fine-tuning chromatographic selectivity of the created hybrid organic-inorganic stationary phases. This review focuses on recent developments in the design, synthesis, characterization, properties, and applications of sol-gel stationary phases in CEC.
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Affiliation(s)
- Wen Li
- Department of Chemistry, University of South Florida, Tampa, FL 33620-5250, USA
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Nakashima R, Kitagawa S, Yoshida T, Tsuda T. Study of flow rate in pressurized gradient capillary electrochromatography using splitter and separation of peptides using an Amide stationary phase. J Chromatogr A 2004; 1044:305-9. [PMID: 15354452 DOI: 10.1016/j.chroma.2004.03.081] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A pressurized gradient capillary electrochromatograph using a splitter was constructed. The variation in flow rate during gradient elution was investigated and separations of peptides using an Amide stationary phase were demonstrated. The flow rate, which is one of the important factors to control chromatographic behavior, was increased during the gradient elution, and the mismatching of mobile phase between the column and the resistance tubing derived three variation patterns in the flow rate. The electrophoretic migration in electrochromatography could enhance in separation of peptides. The separated peak number of tryptic digest of bovine serum albumin was increased from 30 to 40 by the application of +5 kV.
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Affiliation(s)
- Rie Nakashima
- Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan
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Affiliation(s)
- Wes W C Quigley
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
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