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Suzuki N, Taura D, Komichi Y. Critical micelle concentration and partition coefficient of mixed micelles: Analysis of ternary systems based on Markov chain model and simple mixture model. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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2
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Suzuki N. Regular solution theory for nonlinear composition dependency of enantioselectivity by mixed micelle. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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3
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Proskurnin MA, Bendrysheva SN, Smirnova AP. Thermal lens spectrometry in electromigration methods of analysis. JOURNAL OF ANALYTICAL CHEMISTRY 2016. [DOI: 10.1134/s1061934816050105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Sun Y, Li Y, Zeng J, Lu Q, Li PCH. Microchip electrophoretic separation and fluorescence detection of chelerythrine and sanguinarine in medicinal plants. Talanta 2015; 142:90-6. [PMID: 26003696 DOI: 10.1016/j.talanta.2015.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 03/29/2015] [Accepted: 04/02/2015] [Indexed: 12/17/2022]
Abstract
A new method has been developed for separation of chelerythrine and sanguinarine in medicinal plants used in traditional Chinese medicine (TCM). The separation is achieved by microchip electrophoresis (CE) using laser-induced fluorescence detection. The CE separation is achieved by using a hydro-organic medium as the electrolyte buffer. The experimental results are consistent with the prediction by theory in terms of resolution and migration speed because of the low Joule heat generated in microchip CE. In addition, formamide was found to have a potential for separation of molecules with similar chemical structures. Based on these findings, a run buffer containing 50% formamide was used to separate chelerythrine (CHE) and sanguinarine (SAN). The influencing factors, such as solvent of run buffer, pH of buffer, separation distance, and separation voltage, were optimized. Baseline separation of chelerythrine and sanguinarine was achieved within 120 s under an electrical voltage of 1.8 kV. Good linearity was observed in the concentration range of 0.15-550 μg mL(-1) (r=0.9993) for CHE and in the range of 0.3-600 μg mL(-1) (r=0.9998) for SAN. A low limit of detection (LOD) was achieved because of the high sensitivity achieved by laser-induced fluorescence detection (i.e. 5.0 ng mL(-1) and 2.0 ng mL(-1) for CHE and SAN, respectively). The contents of CHE are found to be 641.8±7.5 and 134.0±2.3 mg/kg in extracts of Macleaya cordata and Chelidonium majus, respectively, with good recovery of above 99%. The corresponding values for SAN found in these Chinese herbal extracts are 681.8±7.9 mg/kg and 890.5±8.9 mg/kg, respectively.
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Affiliation(s)
- Yue Sun
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China; Key Laboratory of State Administration of TCM for Digital Quality Evaluation of Chinese Materia Medica, Guangzhou 510006, China; Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangzhou 510006, China.
| | - Yuanyuan Li
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Jiajian Zeng
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Qixian Lu
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Paul C H Li
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6.
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Hou J, Li G, Wei Y, Lu H, Jiang C, Zhou X, Meng F, Cao J, Liu J. Analysis of five alkaloids using surfactant-coated multi-walled carbon nanotubes as the pseudostationary phase in nonaqueous capillary electrophoresis. J Chromatogr A 2014; 1343:174-81. [PMID: 24720903 DOI: 10.1016/j.chroma.2014.03.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 03/18/2014] [Accepted: 03/21/2014] [Indexed: 02/07/2023]
Abstract
In this paper, surfactant-coated multi-walled carbon nanotubes (SC-MWNTs) have been proposed as a novel pseudostationary phase (PSP) to enhance the separation of isoquinoline alkaloids in nonaqueous capillary electrophoresis (NACE). Several parameters affecting NACE separation were studied including the MWNT concentration, the electrolyte concentration, pH* and the separation voltage. In comparison to conventional NACE, the addition of an MWNT dispersion using surfactant solutions in the electrolyte produced an important enhancement in the resolution due to the π-π interactions between the analytes and the surface of the carbon nanotubes. Using SC-MWNTs (6μgmL(-1)) as a PSP in the background electrolyte (BGE) (i.e., 20mM sodium acetate in methanol-acetonitrile (80:20, v/v)) provided the complete separation of five alkaloids. Finally, the developed method has been successfully applied to the detection and quantification of the tested compounds of Rhizoma Coptidis.
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Affiliation(s)
- Jingyi Hou
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China
| | - Geng Li
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China
| | - Yingqin Wei
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China; School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, PR China
| | - Heng Lu
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China
| | - Chao Jiang
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China
| | - Xiaoteng Zhou
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China
| | - Fanyun Meng
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China.
| | - Jun Cao
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, PR China.
| | - Jinxin Liu
- Area Major Laboratory of Protection and Utilization of Traditional Chinese Medicine, Beijing Normal University, Haidian District, Beijing 100088, PR China; State Key Laboratory Breeding Base of Dao-di Herbs, China Academy of Chinese Medical Sciences, Beijing 100700, PR China.
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6
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Ferey L, Delaunay N, Rutledge DN, Cordella CB, This H, Huertas A, Raoul Y, Gareil P. Optimizing separation conditions of 19 polycyclic aromatic hydrocarbons by cyclodextrin-modified capillary electrophoresis and applications to edible oils. Talanta 2014; 119:572-81. [DOI: 10.1016/j.talanta.2013.11.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 11/18/2013] [Accepted: 11/23/2013] [Indexed: 01/22/2023]
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7
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Su J, Xu J, Zhong S, Chen L, Li X, Zou H. Analysis of Dye Components in Red Ballpoint Pen Inks by Nonaqueous Micellar Electrokinetic Chromatography with LIF Detection. Chromatographia 2014. [DOI: 10.1007/s10337-013-2619-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Ali I, Sanagi MM, Aboul-Enein HY. Advances in chiral separations by nonaqueous capillary electrophoresis in pharmaceutical and biomedical analysis. Electrophoresis 2013; 35:926-36. [DOI: 10.1002/elps.201300222] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 05/27/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Imran Ali
- Department of Chemistry, Jamia Millia Islamia; (Central University) Jamia Nagar; New Delhi India
| | - Mohd Marsin Sanagi
- Department of Chemistry, Faculty of Science; Universiti Teknologi Malaysia; Johor Malaysia
| | - Hassan Y. Aboul-Enein
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical and Drug Industries Research Division; National Research Centre; Dokki Cairo Egypt
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9
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Hancu G, Simon B, Rusu A, Mircia E, Gyéresi Á. Principles of micellar electrokinetic capillary chromatography applied in pharmaceutical analysis. Adv Pharm Bull 2013; 3:1-8. [PMID: 24312804 PMCID: PMC3846027 DOI: 10.5681/apb.2013.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/27/2012] [Accepted: 10/27/2012] [Indexed: 11/17/2022] Open
Abstract
Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.
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Affiliation(s)
- Gabriel Hancu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy, Târgu Mureş, Romania
| | - Brigitta Simon
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy, Târgu Mureş, Romania
| | - Aura Rusu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy, Târgu Mureş, Romania
| | - Eleonora Mircia
- Department of Organic Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy, Târgu Mureş, Romania
| | - Árpád Gyéresi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy, Târgu Mureş, Romania
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10
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Study on the use of boromycin as a chiral selector in capillary electrophoresis. J Chromatogr A 2012; 1237:128-32. [DOI: 10.1016/j.chroma.2012.02.073] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 02/07/2023]
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11
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Determination of tocopherols in vegetable oil samples by non-aqueous capillary electrophoresis (NACE) with fluorimetric detection. J Food Compost Anal 2012. [DOI: 10.1016/j.jfca.2011.04.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Mallah A, Memon SQ, Khuhawar MY, Solangi AR, Bhanger MI. Micellar electrokinetic chromatographic separation and quantitative analysis of thorium, uranium, gold, and mercury from environmental ore samples. ACTA CHROMATOGR 2011. [DOI: 10.1556/achrom.23.2011.1.4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Puangpila C, Petsom A, Nhujak T. Theoretical models of separation selectivity for charged compounds in micellar electrokinetic chromatography. Electrophoresis 2010; 32:203-9. [DOI: 10.1002/elps.201000405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 10/18/2010] [Accepted: 10/18/2010] [Indexed: 11/05/2022]
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14
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Mallah A, Memon SQ, Solangi AR, Khuhawar MY, Bhanger MI. Micellar electrokinetic chromatographic separation and analysis of thorium, uranium, gold, and mercury in environmental ore samples. ACTA CHROMATOGR 2010. [DOI: 10.1556/achrom.22.2010.3.5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Xu L, Basheer C, Lee HK. Solvent-bar microextraction of herbicides combined with non-aqueous field-amplified sample injection capillary electrophoresis. J Chromatogr A 2010; 1217:6036-43. [DOI: 10.1016/j.chroma.2010.07.072] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 07/26/2010] [Accepted: 07/28/2010] [Indexed: 12/22/2022]
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16
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Vítková K, Petr J, Maier V, Znaleziona J, Ševčík J. Study of electromigration effects on a pH boundary during the on-line electrokinetic preconcentration by capillary electrophoresis. Electrophoresis 2010; 31:2771-7. [DOI: 10.1002/elps.200900663] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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17
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A fast determination of yohimbine in pharmaceuticals by micellar electrokinetic chromatography. OPEN CHEM 2010. [DOI: 10.2478/s11532-009-0149-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AbstractA method for the fast determination of yohimbine, a potent adrenoreceptor antagonist used for the treatment of sexual dysfunctions, is proposed in this article. MEKC under basic and acidic conditions (sodium borate, pH 9.5 and sodium phosphate, pH 2.5) with SDS was developed. The effect of the experimental parameters, e.g. pH, SDS concentration and injection time, on yohimbine migration was also studied. Both methods were validated in terms of linearity, limits of detection and quantification, accuracy, and precision using caffeine as an internal standard. The application for the determination of yohimbine in hand-made medicaments is also investigated in this study.
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18
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Mikus P, Maráková K. Advanced CE for chiral analysis of drugs, metabolites, and biomarkers in biological samples. Electrophoresis 2010; 30:2773-802. [PMID: 19653234 DOI: 10.1002/elps.200900173] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An analysis of recent trends indicates that CE can show real advantages over chromatographic methods in ultratrace enantioselective determination of biologically active compounds in complex biological matrices. It is due to high separation efficiency and many applicable in-capillary electromigration effects in CE (countercurrent migration, stacking effects) enhancing significantly (enantio)separability and enabling effective sample preparation (preconcentration, purification, analyte derivatization). Other possible on-line combinations of CE, such as column coupled CE-CE techniques and implementation of nonelectrophoretic techniques (extraction, membrane filtration, flow injection) into CE, offer additional approaches for highly effective sample preparation and separation. CE matured to a highly flexible and compatible technique enabling its hyphenation with powerful detection systems allowing extremely sensitive detection (e.g. LIF) and/or structural characterization of analytes (e.g. MS). Within the last decade, more as well as less conventional analytical on-line approaches have been effectively utilized in this field and their practical potentialities are demonstrated on many new application examples in this article. Here, three basic areas of (enantioselective) drug bioanalysis are highlighted and supported by a brief theoretical description of each individual approach in a compact review structure (to create integrated view on the topic), including (i) progressive enantioseparation approaches and new enantioselective agents, (ii) in-capillary sample preparation (preconcentration, purification, derivatization), and (iii) detection possibilities related to enhanced sensitivity and structural characterization.
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Affiliation(s)
- Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.
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Gómez-Caravaca AM, Carrasco-Pancorbo A, Segura-Carretero A, Fernández-Gutiérrez A. NACE-ESI-TOF MS to reveal phenolic compounds from olive oil: Introducing enriched olive oil directly inside capillary. Electrophoresis 2009; 30:3099-3109. [DOI: 10.1002/elps.200800798] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Abstract
This paper summarizes the history of chiral separations done by using electromigration methods with CDs. Several enantioresolution mechanisms and a wide number of chiral selectors have been applied to the separation of optical isomers by CE. Among them inclusion-complexation with CDs or their derivatives played a very important role in CE. Since the beginning our group was involved in studying method optimization for enantiomer resolution by using these chiral selectors. One of our publications was the basis for further development in the field, at least for us. New chiral selectors, development of theory, new methodological approaches and a wide number of practical applications are the main results achieved in the last almost 25 years using CE as an enantioseparative technique.
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Affiliation(s)
- Salvatore Fanali
- Institute of Chemical Methodologies, National Council of Research, Area della Ricerca di Roma I, Monterotondo Scalo (Rome), Italy.
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21
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Caupène C, Martin C, Lemarié M, Perrio S, Metzner P. Mild and efficient access to lithium alkanesulfinates based on oxaziridine-promoted oxidation of thiolates. J Sulphur Chem 2009. [DOI: 10.1080/17415990902903009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Caroline Caupène
- a Laboratoire de Chimie Moléculaire et Thio-Organique, ENSICAEN, Université de Caen Basse-Normandie, CNRS , 6 Boulevard du Maréchal Juin, 14050, Caen, France
| | - Claudie Martin
- a Laboratoire de Chimie Moléculaire et Thio-Organique, ENSICAEN, Université de Caen Basse-Normandie, CNRS , 6 Boulevard du Maréchal Juin, 14050, Caen, France
| | - Margareth Lemarié
- a Laboratoire de Chimie Moléculaire et Thio-Organique, ENSICAEN, Université de Caen Basse-Normandie, CNRS , 6 Boulevard du Maréchal Juin, 14050, Caen, France
| | - Stéphane Perrio
- a Laboratoire de Chimie Moléculaire et Thio-Organique, ENSICAEN, Université de Caen Basse-Normandie, CNRS , 6 Boulevard du Maréchal Juin, 14050, Caen, France
| | - Patrick Metzner
- a Laboratoire de Chimie Moléculaire et Thio-Organique, ENSICAEN, Université de Caen Basse-Normandie, CNRS , 6 Boulevard du Maréchal Juin, 14050, Caen, France
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Validation of a nonaqueous capillary electrophoretic method for the enantiomeric purity determination of R-flurbiprofen using a single-isomer amino cyclodextrin derivative. J Chromatogr A 2008; 1204:219-25. [DOI: 10.1016/j.chroma.2008.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 05/13/2008] [Accepted: 06/03/2008] [Indexed: 11/18/2022]
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Sázelová P, Kasicka V, Koval D, Prusík Z, Fanali S, Aturki Z. Control of EOF in CE by different ways of application of radial electric field. Electrophoresis 2007; 28:756-66. [PMID: 17315148 DOI: 10.1002/elps.200600418] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Various ways of application of radial electric field for the control of electrokinetic potential and EOF in a home-made device for CE are presented. The device comprises three high-voltage power supplies, which are used to form a radial electric field across the fused-silica capillary wall. One power supply provides the internal electric field - a driving force for electrophoretic migration of charged analytes and for the EOF. Two power supplies are connected to the ends of the outer low-conductivity polymeric coating, which is formed by the dispersion of insoluble conductive copolymer of aniline and p-phenylendiamine in polystyrene matrix (dissolved in N-methylpyrrolidone) attached to the original outer polyimide coating of the capillary. They are able to constitute the external longitudinal electric field with variable values of electric potential at both ends of the outer coating. The potential gradient between the external and internal electric field is perpendicular to the capillary wall and forms a radial electric field across the capillary wall, which affects the electrokinetic potential at the solid-liquid interface and EOF inside the capillary. The developed device and methodology has been applied for the analysis of both chiral and achiral molecules such as terbutaline enantiomers and oligopeptides (diglycine and triglycine). The effect of magnitude, orientation, and different ways of application of the radial electric field on the flow rate of the EOF and on the speed, efficiency, and resolution of CZE separations of the above analytes in the internally noncoated fused-silica capillaries have been evaluated.
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Affiliation(s)
- Petra Sázelová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Carabias-Martínez R, Rodríguez-Gonzalo E, Domínguez-Alvarez J, Miranda-Cruz E. Development of a chemometric correlation technique to estimate acid–base descriptors for cationic acids in non-aqueous media. Anal Chim Acta 2007; 584:410-8. [PMID: 17386632 DOI: 10.1016/j.aca.2006.11.036] [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] [Received: 05/10/2006] [Revised: 09/22/2006] [Accepted: 11/14/2006] [Indexed: 11/24/2022]
Abstract
We propose a procedure for estimating acid-base constants in organic solvents or mixture of solvents from the corresponding pK(a) values in aqueous medium and from certain properties of the organic solvents that characterize them. To accomplish this, we developed and validated a chemometric correlation for the calculation of the acid-base constants of different cationic acids in a broad variety of non-aqueous solvents. The parameters chosen for building the model were as follows: the acid-base constant of the compound in aqueous medium and those corresponding to the polarity-polarizability, basicity and acidity scales of the solvent. The results of the fitting were significant (p<0.01), with a root mean error in cross-validation of 18%, with no overfitting. The prediction of the acid-base constants for an external set of compounds had a mean absolute prediction error value of less than 0.8 pK(a) units.
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Affiliation(s)
- R Carabias-Martínez
- Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca, Spain
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25
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Timerbaev AR, Vasylenko OO, Foteeva LS, Rudnev AV, Semenova O, Keppler BK. Application of micellar and microemulsion electrokinetic chromatography for characterization of gallium(III) complexes of pharmaceutical significance. J Sep Sci 2007; 30:399-406. [PMID: 17396599 DOI: 10.1002/jssc.200600305] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
CE with conventional UV detection has recently been shown as a highly effective means to assaying cytotoxic gallium(III)-based compounds with regard to desirable drug-like properties such as the stability and binding to serum proteins. In this extension of that work, different CE techniques are used to further characterize a given set of gallium coordination compounds with established antiproliferating efficacy. Using free-zone CE mode, the electrophoretic profiles of complexes are recorded in order to assess their actual charge state under physiological buffer conditions. Micellar and microemulsion electrokinetic chromatographic techniques are tested as tools for the rapid estimation of the n-octanol-water partition coefficient (log P) that provides a rationale estimate of a drug's ability to cross biological membranes. A range of electrolyte buffer systems with varying (both in the nature and concentration) organic modifiers are examined to evaluate their effect on the relationship between experimental or calculated log P and the retention factors of compounds (log k'). Both methods were found to be better applicable for neutral than for cationic Ga complexes, the microemulsion mode demonstrating superior lipophilicity estimations as well as statistically meaningful log P versus log k' correlations when all the complexes were included in one regression set.
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Affiliation(s)
- Andrei R Timerbaev
- Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, Russia.
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Merino F, Rubio S, Pérez-Bendito D. Supramolecular systems-based extraction-separation techniques coupled to mass spectrometry. J Sep Sci 2006; 28:1613-27. [PMID: 16224955 DOI: 10.1002/jssc.200500161] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The combination of supramolecular chemistry and MS has not only been fruitful in the field of gas-phase fundamental studies of host-guest complexes and supramolecular assemblies. Mass spectrometric analysis has also benefited from the ability of supramolecular systems to behave as pseudophases in which solutes partition from the bulk solvent phase. Supramolecular systems-based extraction and concentration schemes and separation techniques have been widely used in different fields of analytical chemistry and are ideally suited for coupling with MS. This review describes the present status of the application of supramolecular chemistry in mass spectrometric analysis and includes topics such as the use of coacervative liquid-liquid extraction and hemimicelle/admicelle-based SPE of organic compounds prior to chromatography and electrophoresis. It also discusses the recent advances in enantioselective analysis using CD in electrophoresis- and chromatography-MS. The potential and analytical challenges of these approaches in environmental and bioanalytical chemistry, where one can expect significant developments in the future, are outlined.
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Affiliation(s)
- Francisco Merino
- Department of Analytical Chemistry, Campus de Rabanales, Edificio Anexo Marie Curie, University of Córdoba, Córdoba, Spain
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Bendrysheva SN, Proskurnin MA, Pyell U, Faubel W. Sensitivity improvement in capillary electrophoresis using organo-aqueous separation buffers and thermal lens detection. Anal Bioanal Chem 2006; 385:1492-503. [PMID: 16865338 DOI: 10.1007/s00216-006-0602-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 05/31/2006] [Accepted: 06/08/2006] [Indexed: 10/24/2022]
Abstract
It is shown that organo-aqueous separation buffers show much promise when used in capillary electrophoresis separations with photothermal (thermal lens) detection systems. Acetonitrile-water and methanol-water mixtures were selected, as conventionally used in capillary electrophoresis. It is shown that, despite more sophisticated experimental conditions (significant heat outflow from the capillary body) and peak detection, the theoretical ratio of the thermal lens signal for a binary mixture to the thermal lens signal for an aqueous solution (or the corresponding ratio obtained experimentally under bulk batch conditions) can be used to predict the sensitivity of thermal lens detection in capillary electrophoresis. The limits of detection for 2-, 3-, and 4-nitrophenols selected as model compounds in 70% v/v acetonitrile separation buffers are 1 x 10(-6) M, 1 x 10(-6) M and 3 x 10(-7) M, respectively, and are therefore decreased by a factor of six compared to thermal lens detection in aqueous separation buffers. The overall increase in the thermal lens detection sensitivity in a 100% ACN buffer is a factor of 13.
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28
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Van Eeckhaut A, Michotte Y. Chiral separations by capillary electrophoresis: Recent developments and applications. Electrophoresis 2006; 27:2880-95. [PMID: 16688697 DOI: 10.1002/elps.200500375] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper provides an overview of the different classes of chiral selectors that are used in CE. The main properties of every class are described, together with the mechanism of enantioseparation. Newly introduced selectors are also discussed. Pharmaceutical and biomedical applications published from January 2004 till March 2005 are summarized.
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Affiliation(s)
- Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Pharmaceutical Institute, Vrije Universiteit Brussel, Brussels, Belgium
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29
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Rossi M, Campa C, Gamini A, Coslovi A, Donati I, Vetere A, Paoletti S. Separation of O- and C-allyl glycoside anomeric mixtures by capillary electrophoresis and high-performance liquid chromatography. J Chromatogr A 2006; 1110:125-32. [PMID: 16480732 DOI: 10.1016/j.chroma.2006.01.078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 12/09/2005] [Accepted: 01/18/2006] [Indexed: 11/16/2022]
Abstract
Rapid and reliable methods for the analysis of O- and C-allyl galactopyranosides and glucopyranosides are presented, based on capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC). In MEKC, the formation of chromophoric and charged complexes between the saccharides and borate as well as the hydrophobic interactions with micelles jointly contributed to the selective separation and sensitive detection of all the investigated anomeric couples. Some non-purified synthesis mixtures of C-allyl glycosides were successfully characterised without pre-treatment. MEKC buffer conditions for which glycosides separation was successfully achieved were then exported and applied to reverse-phase liquid chromatography (RP-HPLC), for the quantitative isolation of each allyl glycoside anomer. Identification of the obtained anomeric products was performed by electrospray mass spectrometry and (13)C NMR spectroscopy. Glycoside-solvent interactions driving the selective anomeric separation were shortly addressed and discussed on the basis of sugar derivatives structural differences.
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Affiliation(s)
- Marco Rossi
- Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy
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30
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Nozal L, Simonet B, Arce L, Ríos A, Valcárcel M. Use of basic amphiprotic organic solvents containing neutral-surfactant aggregates as pseudostationary phase in non-aqueous capillary electrophoresis. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Servais AC, Fillet M, Chiap P, Dewé W, Hubert P, Crommen J. Influence of the nature of the electrolyte on the chiral separation of basic compounds in nonaqueous capillary electrophoresis using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin. J Chromatogr A 2005; 1068:143-50. [PMID: 15844552 DOI: 10.1016/j.chroma.2004.12.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The influence on the enantiomeric resolution of the nature of the cationic BGE component (sodium, ammonium or potassium) and that of the anionic component (chloride, formate, methanesulfonate or camphorsulfonate) as well as the concentration of heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD), the selected chiral selector, was studied in nonaqueous capillary electrophoresis (NACE). For this purpose, two D-optimal designs with 33 and 26 experimental points were applied. Three beta-blockers (atenolol, celiprolol and propranolol) and three local anesthetics (bupivacaine, mepivacaine and prilocaine) were selected as basic model compounds. Both cationic and anionic BGE components were found to have a deep impact on the enantiomeric resolution of the investigated analytes but it is the cationic component that has shown the strongest influence. Indeed, in some cases, the change of the latter led to a complete loss of enantioresolution. Based on the observed results, two NACE systems were recommended, namely ammonium formate and potassium camphorsulfonate in a methanolic solution containing HDMS-beta-CD and acidified with formic acid, in order to separate efficiently the enantiomers of basic drugs.
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Affiliation(s)
- Anne-Catherine Servais
- Department of Analytical Pharmaceutical Chemistry, Institute of Pharmacy, University of Liège, Avenue de l'Hopital 1, CHU, B36, B-4000 Liège 1, Belgium
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32
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Schuster SA, Foley JP. Effect of surfactant counterion and organic modifier on the properties of surfactant vesicles in electrokinetic chromatography. J Sep Sci 2005; 28:1399-408. [PMID: 16138692 DOI: 10.1002/jssc.200500208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Counterion and organic modifier are two parameters in EKC that can be varied in order to obtain improved solubility, selectivity, and efficiency. The effect of changing surfactant counterion and/or organic modifier on the chromatographic and electrophoretic properties of cetyltrimethylammonium bromide (CTAB)/sodium octyl sulfate (SOS) vesicles is examined in EKC. The vesicles are prepared in a 1:3.66 cationic/ anionic mole ratio for a total surfactant concentration of 69 mM. The cationic CTAB is replaced by cetyltrimethylammonium chloride (CTAC) and the first use of CTAC/SOS vesicles is reported. The mean diameter of the CTAC/SOS vesicles is 96 nm while that of the CTAB/SOS vesicles is 85 nm. A class I modifier (2-amino-1-butanol) and a class II modifier (acetonitrile) have similar effects on the EOF, elution range, methylene selectivity, and the efficiency of the CTAB/SOS vesicles and the CTAC/SOS vesicles. Upon addition of 10% ACN, there is roughly a 10-fold increase in the efficiency of heptanophenone, a model hydrophobic compound, compared to the efficiency using unmodified vesicles. Linear free energy relationship (LFER) analysis using the Abraham solvation model is employed to characterize solute-vesicle interactions. The results suggest that organic modifier-vesicle interactions depend somewhat on the counterion.
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33
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Abstract
Enantiomer separations by CE employing nonaqueous conditions are reviewed. The general focus of this article is directed towards solvent effects on chiral recognition and the separation mechanism. After a general discussion of solvent effects on the individual processes involved in CE enantiomer separation, specifics for various selector classes are discussed together with a few applications of enantioselective nonaqueous CE.
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Affiliation(s)
- Michael Lämmerhofer
- Christian Doppler Laboratory for Molecular Recognition Materials, Institute of Analytical Chemistry, University of Vienna, Währingerstrasse 38, A-1090 Vienna, Austria.
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34
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Lin CE. Determination of critical micelle concentration of surfactants by capillary electrophoresis. J Chromatogr A 2004; 1037:467-78. [PMID: 15214683 DOI: 10.1016/j.chroma.2003.11.059] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Capillary electrophoresis (CE) has been proven to be a convenient and useful technique for the determination of the critical micelle concentration (CMC) of a surfactant in an electrophoretic system under operating conditions. In this review, methodological approaches to the determination of the CMC of surfactants by CE technique are described. The practical requirements for making such measurements and the CMC values of surfactants determined by CE methods are presented. In addition, difficulties and uncertainty, as well as misconceptions that may arise in the CMC determination are discussed.
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Affiliation(s)
- Ching-Erh Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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35
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Xu L, Feng YQ, Shi ZG, Da SL, Gu JM. Nonaqueous capillary electrophoresis using a zirconia-coated capillary. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.03.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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Janos P. Determination of equilibrium constants from chromatographic and electrophoretic measurements. J Chromatogr A 2004; 1037:15-28. [PMID: 15214658 DOI: 10.1016/j.chroma.2003.11.101] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chemical interactions, such as acid-base, complex-forming, ion association and other equilibria, are widely exploited to improve the separation efficiency in liquid chromatography as well as in electrophoresis. On the other hand, these techniques can be advantageously used to study the chemical equilibria affecting the separations. If the equilibium is sufficiently fast in comparison with the separation process, then the retention characteristics in chromatography (retention factors) or the migration characteristics in electrophoresis (effective mobilities) may be expressed as functions of the composition of mobile phase or background electrolyte (BGE), respectively. Using a proper experimental arrangement, the dependencies of retention (migration) characteristics on the mobile phase (background electrolyte) composition can be measured and utilized to calculate the equilibrium constants for equlibria taking place in the mobile phase (background electrolyte). Although principles of these measurements have been known for a long time, only more recent studies utilizing HPLC and capillary electrophoretic techniques are reviewed in this paper.
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Affiliation(s)
- Pavel Janos
- Faculty of Environmental Studies, University of Jan Evangelista Purkynĕ, Králova Výsina 7, 400 96 Ustí nod Labem, Czech Republic.
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37
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Xu L, Feng YQ, Shi ZG, Da SL, Ren YY. Nonaqueous capillary electrophoresis using a titania-coated capillary. J Chromatogr A 2004; 1028:165-70. [PMID: 14969290 DOI: 10.1016/j.chroma.2003.11.085] [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: 10/26/2022]
Abstract
In this work, an ordered mesoporous titania film was introduced to coat a capillary by means of the sol-gel technique. Its electroosmotic flow (EOF) property was investigated in a variety of nonaqueous media (methanol, formamide and N,N'-dimethylformamide and mixtures of methanol and acetonitrile). The titania-coated capillary exhibited a distinctive EOF behavior, the direction and magnitude of which were strongly dependent on various parameters such as the solvent composition, apparent pH (pH*) and the electrolytes. The nonaqueous capillary electrophoresis separation of several alkaloids was investigated in the positively charged titania-coated capillary. Comparison of separation between coated and uncoated capillaries under optimal nonaqueous conditions was also carried out.
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Affiliation(s)
- Li Xu
- Department of Chemistry, Wuhan University, Wuhan 430072, China
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38
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Schöftner R, Buchberger W. Systematic investigations of different capillary electrophoretic techniques for separation of methylquinolines. J Sep Sci 2003. [DOI: 10.1002/jssc.200301423] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Abstract
As a follow-up to a series of review articles on enantioselective ligand exchange chromatography, the present contribution critically evaluates achievements in this area of active and successful research which have been reported in the scientific since 1992. Also discussed is enantioselective ligand exchange in electromigration techniques which have developed especially fruitfully during the last decade.
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Affiliation(s)
- Vadim A Davankov
- Institute of Organo-Element Compounds, Russian Academy of Sciences, Vavilov Str. 28, Moscow 119991, Russia.
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40
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Wätzig H, Günter S. Capillary electrophoresis-a high performance analytical separation technique. Clin Chem Lab Med 2003; 41:724-38. [PMID: 12880135 DOI: 10.1515/cclm.2003.112] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Capillary electrophoresis (CE) is often one of the preferred techniques in pharmaceutical quality control and in clinical chemistry, particularly considering the high selectivity and lower costs compared to HPLC. The precision of CE is as good as in liquid chromatography (LC). The sample-throughput is high due to short analysis times. Efforts for sample pre-treatment are usually minor in CE. Urine and even blood plasma can be directly injected without further pre-treatment. After summarising the basic principles of CE, general strategies for method development are described to achieve selective, efficient, precise, fast, sensitive, and validated methods. Sample pre-treatment requirements are discussed. Standard buffer recipes, surfactants used in micellar electrokinetic chromatography (MEKC), chiral selectors, useful buffer additives, actions to deal with complex matrices, and aspects of validation have been collected. Other techniques that can be performed with CE instruments, such as capillary isoelectric focusing (CIEF), capillary isotachophoresis (CITP), and capillary electrochromatography (CEC), are briefly discussed.
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Affiliation(s)
- Hermann Wätzig
- Institute for Pharmaceutical Chemistry, Technical University Braunschweig, Braunschweig, Germany.
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41
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Sirén H, Karttunen A. Microemulsion electrokinetic chromatographic analysis of some polar compounds. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 783:113-24. [PMID: 12450530 DOI: 10.1016/s1570-0232(02)00519-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study presents the optimization of a microemulsion electrokinetic chromatographic (MEEKC) electrolyte solution by using UV detection and with the method, simultaneous separations of chemically, biochemically and pharmaceutically related anionic and cationic compounds. Representatives of the compound groups were from isoflavonoids, benzodiazepines, metanephrines, diuretics and peptide hormones. The MEEKC separations under basic conditions were first optimized using a two-component isoflavonoid mixture as the sample and an electrolyte containing 10 mM tetraborate as the main buffer (pH 9.5). The stable microemulsion phase was adjusted with various amounts of octane, 1-butanol and sodium dodecyl sulfate (SDS). An only acidified electrolyte solution used in the study was made of phosphoric acid (pH 1.8) containing octane, SDS and ethyl acetate. The analyses with isoflavonoids showed that electrophoretic mobilities of the investigated compounds were highly related to the concentrations of SDS and 1-butanol with linear and parabolic correlation, respectively. However, addition of octane gave linear correlation only at low concentrations. In most cases four to six structurally related compounds and even 13 diuretics with various polar properties were separated from each other in basic microemulsion medium. The acidified MEEKC electrolyte gave good resolution for anionic metanephrines.
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Affiliation(s)
- Heli Sirén
- Technical Research Centre, VTT Processes, P.O. Box 1602, FIN-02044 VTT, Espoo, Finland.
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42
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Servais AC, Fillet M, Chiap P, Abushoffa AM, Hubert P, Crommen J. Optimization of the separation of β-blockers by ion-pair capillary electrophoresis in non-aqueous media using univariate and multivariate approaches. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1087::aid-jssc1087>3.0.co;2-a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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43
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Wikström H, Owens PK. Development and validation of a chiral capillary electrophoresis method for melagatran and ximelagatran drug substances. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1167::aid-jssc1167>3.0.co;2-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Affiliation(s)
- Wei Shi
- Department of Chemistry, New Mexico Institute of Mining & Technology, Socorro, NM 87801, USA; Fax: +1 406 243 4227
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45
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Shi W, Palmer CP. Effect of pendent group structures on the chemical selectivity and performance of sulfonated copolymers as novel pseudophases in electrokinetic chromatography. Electrophoresis 2002; 23:1285-95. [PMID: 12007128 DOI: 10.1002/1522-2683(200205)23:9<1285::aid-elps1285>3.0.co;2-a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Amphiphilic copolymers of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) with dihydrocholesteryl acrylate (pDHCHAt) or tert-octyl acrylamide (ptOAm) as comonomers were synthesized, characterized and used as new polymeric pseudostationary phases in electrokinetic chromatography. High-efficiency separations with theoretical plates around 500,000 to 870,000/m were achieved. Linear solvation energy relationships analysis of 20 solutes was performed to investigate the retention mechanism. Polycyclic aromatic hydrocarbons (PAHs) were separated under 30% v/v acetonitrile. The separation of nine aromatic model solutes by pDHCHAt showed significantly different selectivity from that of sodium dodecyl sulfate. Although only minor difference in selectivity was found for small aromatic compounds on pDHCHAt and poly(AMPS-lauryl acrylate), significantly different retention mechanism was found for PAHs and n-dodecanophenone comparing both copolymers. Significant chemical selectivity difference was found for selected small aromatic compounds on ptOAm and poly(AMPS-stearyl acrylamide).
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Affiliation(s)
- Wei Shi
- Department of Chemistry, New Mexico Institute of Mining & Technology, Socorro, NM, USA
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46
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Scriba GKE. Selected fundamental aspects of chiral electromigration techniques and their application to pharmaceutical and biomedical analysis. J Pharm Biomed Anal 2002; 27:373-99. [PMID: 11755740 DOI: 10.1016/s0731-7085(01)00653-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
While capillary electrophoresis has been established as a major enantioseparation technique within the last decade, the potential of capillary electrochromatography is still studied extensively. This review summarizes recent applications of electromigration techniques with regard to the enantioseparation of chiral drugs. The first part discusses the general aspects of migration models and the enantiomer migration order. The application of capillary electrophoresis to chiral pharmaceutical analysis considers recent literature on: (1) chiral resolutions of non-racemic mixtures of enantiomers for the development of assays and the determination of the stereochemical purity of the drugs, (2) chiral separations of compounds in pharmaceutical formulations and products, and (3) enantioseparations of drugs in biological samples. A shorter section devoted to chiral electrochromatography discusses some fundamental aspects as well as the application to the chiral analysis of drugs including bioanalysis.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Jena, Philosophenweg 14, D-07743 Jena, Germany.
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47
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Dehouck P, Van Schepdael A, Roets E, Hoogmartens J. Analysis of clindamycin by micellar electrokinetic chromatography with a mixed micellar system. J Chromatogr A 2001; 932:145-52. [PMID: 11695860 DOI: 10.1016/s0021-9673(01)01247-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study details the development and validation of an optimized method with micellar electrokinetic chromatography for the analysis of clindamycin. The method uses a mixed micellar phase containing anionic sodium dodecylsulfate (SDS) and non ionic Brij 35 on an untreated fused-silica capillary. The influences of buffer concentration, pH, SDS, Brij 35 and organic modifier were investigated. Special attention was given to the role of the non ionic Brij 35 in the mixed micellar system. Optimization with a central composite design resulted in optimal separation conditions: background electrolyte containing 25 mM sodium tetraborate pH 7.75, 90 mM SDS, 14 mM Brij 35 and 21% acetonitrile. The applied voltage was 15 kV and the capillary temperature 15 degrees C. The method was robust and gave good linearity and repeatability. The limits of detection and quantitation were 0.05 and 0.15%, respectively, relative to a 2.5 mg/ml clindamycin solution. Two commercial bulk products were analysed with this system.
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Affiliation(s)
- P Dehouck
- Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, K.U. Leuven, Belgium
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48
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Abstract
A review is presented that surveys the basic theory of direct separation of enantiomers by capillary electrophoretic (CE) techniques. These separations are based on the formation of diastereomeric complexes between the enantiomeric analytes and a chiral selector added to the electrolyte solution. The review covers a comprehensive treatment of the equations needed for optimization of selectivity coefficients, resolution and analysis time in the zone electrophoretic mode. In this context, it takes into account combined equilibria of complexation and protonation/deprotonation as well as complexation and paritition into micelles. On the basis of these equations, the benefits of charged selectors and the optimization potential inherent to pH tuning can be documented. In addition, the review deals with some basic aspects of chiral isoelectric focusing and briefly discusses indirect enantioseparation. In a subsequent section a survey is given on particularfeatures of the various types of chiral selectors. Finally, the recent developments in preparative enantioseparation in continuous free-flow system and by use of isoelectric membranes are discussed.
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Affiliation(s)
- A Rizzi
- Institute of Analytical Chemistry, University of Vienna, Austria.
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49
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Wang Z, Wan H, Anderson MS, Abdel-Rehim M, Blomberg LG. Separation of lidocaine and its metabolites by capillary electrophoresis using volatile aqueous and nonaqueous electrolyte systems. Electrophoresis 2001; 22:2495-502. [PMID: 11519953 DOI: 10.1002/1522-2683(200107)22:12<2495::aid-elps2495>3.0.co;2-i] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The separation of the basic drug lidocaine and six of its metabolites has been investigated both by using volatile aqueous electrolyte system, at low pH and by employing non-aqueous electrolyte systems. In aqueous systems, the best separation of the compounds under the investigated conditions was achieved by using the electrolyte 60 mM trifluoroacetic acid (TFA)/triethylamine (TEA) at pH 2.5 containing 15% methanol. With this electrolyte, all seven compounds were well separated with high efficiency and migration time repeatability. The separations with bare fused-silica capillaries and polyacrylamide-coated capillaries were compared with higher separation efficiency with the latter. On the other hand, near baseline separation of all the seven compounds was also obtained by employing the non-aqueous electrolyte, 40 mM ammonium acetate in methanol and TFA (99:1, v/v), with comparable migration time repeatability but lower separation efficiency relative to the aqueous system.
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Affiliation(s)
- Z Wang
- Department of Chemistry, Karlstad University, Sweden
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50
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Shi W, Peterson DS, Palmer CP. Effect of pendant chain lengths and backbone functionalities on the chemical selectivity of sulfonated amphiphilic copolymers as pseudo-stationary phases in electrokinetic chromatography. J Chromatogr A 2001; 924:123-35. [PMID: 11521859 DOI: 10.1016/s0021-9673(01)00760-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amphiphilic copolymers of AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and hydrophobic monomers with various chemical structures were synthesized, characterized and used as novel electrokinetic chromatography polymeric pseudo-stationary phases, showing significant chemical selectivity differences from that of the conventional monomeric pseudo-stationary phase, sodium lauryl sulphate. Copolymers of AMPS and methacrylates with different pendant chain lengths (C8, C12 and C18) were investigated and no significant difference in chemical selectivity was observed among them. However, the spacer bonding chemistry was shown to contribute to significant chemical selectivity difference, e.g. poly(AMPS-lauryl methacrylate) showed different chemical selectivity from poly(AMPS-lauryl methacrylamide). Linear solvation energy relationship analysis of 20 solutes by eight different polymeric pseudo-stationary phases was employed to investigate the solute molecule structural contributions to the retention. Hydrogen-bonding properties (described by system constants b and a) of poly(AMPS-alkyl methacrylamide) were found stronger than those of poly(AMPS-alkyl methacrylate).
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Affiliation(s)
- W Shi
- Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro 87801, USA
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