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Fukai N, Kitagawa S, Ohtani H. Effect of surfactant species and electrophoretic medium composition on the electrophoretic behavior of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis. Electrophoresis 2017; 38:1724-1729. [DOI: 10.1002/elps.201700013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/30/2017] [Accepted: 04/11/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Nao Fukai
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology; Nagoya Japan
| | - Shinya Kitagawa
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology; Nagoya Japan
| | - Hajime Ohtani
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology; Nagoya Japan
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2
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Smela E. Challenges in realizing a self-contained hydraulically-driven contractile fiber actuator. Faraday Discuss 2017; 199:465-485. [DOI: 10.1039/c6fd00235h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The field of soft robots would benefit from electrically controlled contractile actuators in the form of fibers that achieve a strain of 20% in less than a second while exerting high force. This work explores possible designs for achieving this goal using self-contained electroosmotic fluid pumping within a tube-shaped structure. The most promising configuration is a combination of a bellows and a McKibben-type muscle, since pumping fluid from the former to the latter results in contraction of both portions. Realizing such a device entails challenges in fabrication and electrokinetic fluid pumping in closed systems. Further studies of electroosmotic flow in salt-free organic solvents are needed.
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Affiliation(s)
- Elisabeth Smela
- Department of Mechanical Engineering and Institute for Systems Research
- University of Maryland
- College Park
- USA
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3
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FUKAI N, KITAGAWA S, OHTANI H. Separation of Water-Insoluble and Neutral Linear Synthetic Polymers in Nonaqueous Capillary Zone Electrophoresis Using Phosphonium-Based Ionic Liquid. CHROMATOGRAPHY 2017. [DOI: 10.15583/jpchrom.2017.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Nao FUKAI
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology
| | - Shinya KITAGAWA
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology
| | - Hajime OHTANI
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology
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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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5
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Hellqvist A, Hedeland Y, Pettersson C. Evaluation of electroosmotic markers in aqueous and nonaqueous capillary electrophoresis. Electrophoresis 2013; 34:3252-9. [DOI: 10.1002/elps.201300305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 08/13/2013] [Accepted: 09/02/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Alexander Hellqvist
- Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Biomedical Centre; Uppsala University; Uppsala Sweden
| | - Ylva Hedeland
- Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Biomedical Centre; Uppsala University; Uppsala Sweden
| | - Curt Pettersson
- Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Biomedical Centre; Uppsala University; Uppsala Sweden
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6
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Okita Y, Fujisawa S, Saito T, Isogai A. TEMPO-Oxidized Cellulose Nanofibrils Dispersed in Organic Solvents. Biomacromolecules 2010; 12:518-22. [DOI: 10.1021/bm101255x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yusuke Okita
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Shuji Fujisawa
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Tsuguyuki Saito
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Akira Isogai
- Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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7
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Sun H, Lau K, Fung Y. A new capillary electrophoresis buffer for determining organic and inorganic anions in electroplating bath with surfactant additives. J Chromatogr A 2010; 1217:3244-50. [DOI: 10.1016/j.chroma.2010.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 12/24/2009] [Accepted: 01/06/2010] [Indexed: 12/11/2022]
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8
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Liu Q, Li Y, Yao L, Yao S. Use of gemini surfactants as semipermanent capillary coatings in aqueous-organic solvents for capillary electrophoretic separation of inorganic anions. J Sep Sci 2009; 32:4148-54. [DOI: 10.1002/jssc.200900403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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9
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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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10
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Sengwa R, Khatri V, Sankhla S. Dielectric behaviour and hydrogen bond molecular interaction study of formamide-dipolar solvents binary mixtures. J Mol Liq 2009. [DOI: 10.1016/j.molliq.2008.10.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Schappler J, Staub A, Veuthey JL, Rudaz S. Highly sensitive detection of pharmaceutical compounds in biological fluids using capillary electrophoresis coupled with laser-induced native fluorescence. J Chromatogr A 2008; 1204:183-90. [DOI: 10.1016/j.chroma.2008.04.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/18/2008] [Accepted: 04/21/2008] [Indexed: 11/17/2022]
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12
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Otieno AC, Mwongela SM. Capillary electrophoresis-based methods for the determination of lipids--a review. Anal Chim Acta 2008; 624:163-74. [PMID: 18706322 DOI: 10.1016/j.aca.2008.06.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 06/12/2008] [Accepted: 06/17/2008] [Indexed: 01/08/2023]
Abstract
Capillary electrophoresis (CE) is a high-resolution technique for the separation of complex biological and chemical mixtures. CE continues to emerge as a powerful tool in the determination of lipids. Here we review the analytical potential of CE for the determination of a wide range of lipids. The different classes of lipids are introduced, and the different modes of CE and optimization methods for the separation of lipids are described. The advantages and disadvantages of the different modes of CE compared to traditional methods like gas chromatography (GC) and liquid chromatography (LC) in the determination of lipids are discussed. Finally, the potential of CE in the determination of lipids in the future is illustrated.
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Affiliation(s)
- Anthony C Otieno
- Department of Chemistry, Kent State University, Kent, OH 44242, USA
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13
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Cation effects in the separation of calix[4]pyrroles by nonaqueous capillary electrophoresis with tetraalkylammonium chloride salts as background electrolytes. J Chromatogr A 2008; 1192:180-6. [DOI: 10.1016/j.chroma.2008.03.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 03/07/2008] [Accepted: 03/14/2008] [Indexed: 11/24/2022]
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14
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18 Coupling CE and microchip-based devices with mass spectrometry. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s0149-6395(07)00018-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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15
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Liu Q, Liu Y, Li Y, Yao S. Nonaqueous capillary electrophoresis coupled with laser-induced native fluorescence detection for the analysis of berberine, palmatine, and jatrorrhizine in Chinese herbal medicines. J Sep Sci 2007; 29:1268-74. [PMID: 16833085 DOI: 10.1002/jssc.200600032] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
LIF detection is one of the most sensitive detection methods for CE. However, its application is limited because the analyte is usually required to be derivatized with a fluorescent label. As a result, LIF is seldom used to analyze active ingredients in plants. In this work, we introduce a rapid, simple, and sensitive method of nonaqueous CE (NACE) coupled with laser-induced native fluorescence detection for the simultaneous analysis of berberine, palmatine, and jatrorrhizine. This method skillfully utilizes the native fluorescence of these alkaloids and requires no troublesome fluorescent derivatization. As these alkaloids can fluoresce to some degree, they were simply detected by a commercially available 488 nm Ar+ laser. The native fluorescence of the analytes was greatly enhanced by nonaqueous media. Compared with the reported UV detection method, much lower LOD was achieved (6.0 ng/mL for berberine, 7.5 ng/mL for palmatine, and 380 ng/mL for jatrorrhizine). This method was successfully applied to analyze berberine, palmatine, and jatrorrhizine in two Chinese herbal medicines, Rhizoma coptidis and Caulis mahoniae.
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Affiliation(s)
- Qian Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, P. R. China
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16
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Sjödahl J, Lindberg P, Roeraade J. Separation of oligonucleotides in N-methyl-formamide-based polymer matrices by capillary electrophoresis. J Sep Sci 2007; 30:104-9. [PMID: 17313148 DOI: 10.1002/jssc.200600228] [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] [Indexed: 11/10/2022]
Abstract
N-Methylformamide (NMF)-based matrices for capillary electrophoretic separation of nucleic acids have been developed. The use of an organic solvent as liquid base for the separation matrices allowed a hydrophobic polymer, C16-derivatized 2-hydroxyethyl cellulose (HEC), to be employed as structural element in the sieving medium. With a matrix consisting of 5% w/v of this polymer dissolved in NMF containing 50 mM ammonium acetate, p(dA)12-18 and p(dA)40-60 oligonucleotides were baseline separated. The addition of ammonium acetate to the buffer and separation matrix resulted in enhanced separation efficiency. Furthermore, it was possible to tailor the sieving performance of the separation medium by the use of a binary mixture of C16-derivatized HEC and PVP. Differences in sieving behavior of the various matrices evaluated are discussed.
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Affiliation(s)
- Johan Sjödahl
- Department of Analytical Chemistry, KTH School of Chemical Science and Engineering, Stockholm, Sweden.
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17
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Scriba GKE. Nonaqueous capillary electrophoresis-mass spectrometry. J Chromatogr A 2007; 1159:28-41. [PMID: 17316665 DOI: 10.1016/j.chroma.2007.02.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 01/30/2007] [Accepted: 02/05/2007] [Indexed: 11/27/2022]
Abstract
Nonaqueous background electrolytes broaden the application of capillary electrophoresis displaying altered separation selectivity and interactions between analytes and buffer additives compared to aqueous background electrolytes. In addition, nonaqueous capillary electrophoresis (NACE) appears to be ideally suited for online coupling with mass spectrometry due to the high volatility and low surface tension of many organic solvents. Despite these advantages and an increasing use of nonaqueous background electrolytes in CE, coupling of NACE to mass spectrometry has not yet been applied very often to date. The present review summarizes the applications of online NACE-MS with regard to the analysis of drugs, stereoisomers, peptides, alkaloids, polymers and others. A brief discussion of solvent effects in NACE and pH of nonaqueous background electrolyte systems is also presented.
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Affiliation(s)
- Gerhard K E Scriba
- Friedrich-Schiller-University Jena, School of Pharmacy, Philosophenweg 14, 07743 Jena, Germany.
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18
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Lindberg P, Roeraade J. GEL MATRICES IN N-METHYLFORMAMIDE FOR SEPARATION OF DNA FRAGMENTS. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-100101662] [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)
- P. Lindberg
- a Department of Analytical Chemistry , Royal Institute of Technology , Stockholm , S-100 44 , Sweden
| | - J. Roeraade
- a Department of Analytical Chemistry , Royal Institute of Technology , Stockholm , S-100 44 , Sweden
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19
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Laamanen PL, Busi S, Lahtinen M, Matilainen R. Separation of chelating agents as copper complexes by capillary zone electrophoresis using quaternary ammonium bromides as additives in N-methylformamide. Anal Chim Acta 2006; 580:91-8. [PMID: 17723760 DOI: 10.1016/j.aca.2006.07.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 07/17/2006] [Accepted: 07/18/2006] [Indexed: 11/23/2022]
Abstract
This study presents the use of quaternary ammonium bromides as additives in N-methylformamide (NMF) for the separation and quantification of chelating agents as copper complexes by capillary zone electrophoresis (CZE). The new quaternary ammonium bromides were synthesized in our laboratory and used for the first time for CZE applications performed in NMF media. The methods were developed and optimized for determination of six chelating agents (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. Among the tested electrolyte additives in NMF media (pH(app) 10.2) dimethyldioctylammonium bromide (DMDOAB), dimethyldinonylammonium bromide (DMDNAB) and dimethyldidecylammonium bromide (DMDDAB), at a concentration of 20 mmol L(-1) improved the separation of the copper complexes. The optimized methods require only 12 min for one analysis, and the detection limits for copper complexes of DMDNAB, the best-performing additive, were < or =24 micromol L(-1). Relative standard deviations (R.S.D.) for migration times were < or =2.5, < or =2.1, < or =3.1% and for peak areas, < or =3.1, < or =3.0, < or =3.2% for DMDOAB, DMDNAB and DMDDAB used as additives, respectively. All three methods were successfully applied to the analysis of natural and wastewater samples. No matrix effects from these samples were observed. The interaction between quaternary ammonium bromides and copper complexes is discussed.
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Affiliation(s)
- Pirkko-Leena Laamanen
- University of Jyväskylä, Department of Chemistry, PO Box 35, FI-40014 Jyväskylä, Finland.
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20
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Assunção NA, Deziderio LAG, Paulino LG, Lupetti KO, Carrilho E. Nonaqueous capillary electrophoresis in coated capillaries: An interesting alternative for proteomic applications. Electrophoresis 2005; 26:3292-9. [PMID: 16080212 DOI: 10.1002/elps.200500195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This work brings together some contributions for the use of nonaqueous media for proteomic analysis, for both capillary electrophoresis (CE) separation and the preparation of tryptic digests. First, a ternary nonaqueous buffer consisting of 60/30/10 v/v methanol/acetonitrile/acetic acid with 12.5 mmol/L ammonium acetate was optimized for CE separation of the tryptic digest of lysozyme. Lysozyme was chosen as a model system for the protein digestion, which has also been prepared in an organic-rich medium with methanol/50 mmol/L NH(4)HCO(3), pH 8.0 (60/40 v/v). The separation results were compared to in silico (PeptideCutter program) digestion conditions, and high-efficiency peak separation (18 peaks) was obtained in 20 min with an electric field of 350 V/cm. In addition, we have evaluated the stability of a coated capillary with poly-N,N-dimethylacrylamide (60/30 cm total/effective length and 75 microm ID) for over 100 runs of tryptic digest with the nonaqueous background electrolyte solvent system. The migration times for ten selected peptide peaks presented 3-7% relative standard deviation.
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Affiliation(s)
- Nilson A Assunção
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
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21
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Abstract
N,N-Dimethylformamide (DMF) is a dipolar protophilic solvent with physicochemical properties that makes it suitable as solvent for capillary electrophoresis (CE). It is prerequisite for the proper application of CE to adjust and to change the pH of the background electrolyte (BGE) in a defined manner. This was done in the present work using benzoic acid-benzoate by selecting different concentration ratios of acid and salt, and calculating the theoretical pH from the activity-corrected Henderson-Hasselbalch equation. The mobilities of the analytes (chloro- and nitro-substituted phenolates) were found to follow reasonably well the typical sigmoid mobility versus pH curve as predicted by theory. The actual mobilities and pK(a) values (at 25 degrees C) of the analytes were derived from these curves. pK(a) values were in the range of 11.1-11.7, being thus 3-4.4 units higher than in water. This pK(a) shift is caused by the destabilization of the analyte anion and the better stability (solubility) of the molecular analyte acid in DMF, which overcome the higher basicity of DMF compared to water. Absolute mobilities were calculated from the actual mobilities; they were between 32x10(-9) and 42x10(-9) m(2)/Vxs. Slight deviations of the measured mobilities from the theoretical mobility versus pH curve were discussed on the bases of ion pairing and heteroconjugation and homoconjugation of either buffer components or buffer components and analytes. Heteroconjugation was used as a mechanism for the electrically driven separation of neutral analyte molecules in a BGE where salicylate acted as complex forming ion. Rough estimation of the complexation constants for the phenolic analytes gave values in the range of 100-200 L/mol. Addition of water to the solvent decreased the effect of heteroconjugation, but it was still present up to the surprisingly high concentration of 20% water. Electrophoretically relevant parameters like ionic mobilities and pK(a) values, and conjugation and ion pairing are dependent on the water content of the solvent. The water uptake of DMF was measured when exposed to humidity of ambient air. The resulted behavior of the water uptake was found rather similar to that for acetonitrile and methanol.
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Affiliation(s)
- Simo P Porras
- Institute for Analytical Chemistry, University of Vienna, Vienna, Austria.
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22
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Humam M, Bieri S, Geiser L, Muñoz O, Veuthey JL, Christen P. Separation of four isomeric tropane alkaloids from Schizanthus grahamii by non-aqueous capillary electrophoresis. PHYTOCHEMICAL ANALYSIS : PCA 2005; 16:349-56. [PMID: 16223092 DOI: 10.1002/pca.856] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The potential of non-aqueous capillary electrophoresis was investigated for the separation of four isomeric tropane alkaloids, namely 3alpha-senecioyloxy-7beta-hydroxytropane, 3alpha-hydroxy-7beta-senecioyloxytropane, 3alpha-hydroxy-7beta-angeloyloxytropane and 3alpha-hydroxy-7beta-tigloyloxytropane extracted from Schizanthus grahamii. The composition of the organic solvent and the nature of the electrolyte were of considerable importance with respect to selectivity. Different organic solvents (i.e. methanol, ethanol, acetonitrile, tetrahydrofuran) and mixtures thereof were investigated. Moreover, different electrolytes such as formate, acetate and trifluoroacetate were tested. After optimisation, an electrolyte consisting of 1 M trifluoroacetic acid and 25 mM ammonium trifluoroacetate in methanol:ethanol (40:60, v:v) was selected. It provided an efficient separation of the four positional isomers as well as a good repeatability of migration time (RSD < 0.2%). The method was successfully used with electrospray MS to confirm the molecular mass of the tropane alkaloids.
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Affiliation(s)
- M Humam
- Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmaceutical Sciences EPGL, University of Geneva, Switzerland
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23
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Steiner F, Hassel M. Influence of solvent properties on separation and detection performance in non-aqueous capillary electrophoresis–mass spectrometry of basic analytes. J Chromatogr A 2005; 1068:131-42. [PMID: 15844551 DOI: 10.1016/j.chroma.2004.11.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The versatility of non-aqueous capillary electrophoresis (NACE) results mainly from the variety of physico-chemical properties of the different solvents. They provide solubility for a wide range of analytes, enable to control electrophoretic selectivity, but affect in some cases UV absorbance detection. The coupling of NACE to electrospray mass spectrometry (ESI-MS) allows to cope with the high UV cut-off of some CE relevant solvents (e.g., formamides). In this paper the pure organic solvents methanol, acetonitrile, dimethylsulfoxide, formamide, N-methylformamide and N,N-dimethylformamide are evaluated against water for the preparation of ammonium acetate electrolytes to separate the basic model substances 2-aminobenzimidazole, procaine, propranolol and quinine with NACE-MS. MS coupling is assisted with the sheath liquid water-isopropanol (1:4, v/v) with 0.1% formic acid. The goal of the paper is to assess the influence of the solvent on selectivity, separation speed, and peak efficiency for a given set of model compounds on a simple empirical basis. It should give the user an idea how the separation quality is changed when nothing but the running solvent is altered. The obtained efficiency results were discussed with respect to physico-chemical models described in literature (assuming longitudinal diffusion as the only source of band broadening), but no satisfying correlations with solvent properties could be traced. The feasibility of all six organic solvents for MS coupling was demonstrated and the influence of the separation solvent on the MS detection performance was compared. In the seven different solvents, the shortest run time was obtained with acetonitrile, the best peak resolution with the amphiprotic solvents (especially methanol) best peak efficiency with methanol and formamide, and the most sensitive ESI-MS detection with acetonitrile and methanol, but with only slight advantage to water.
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Affiliation(s)
- Frank Steiner
- Instrumental Analysis and Bioanalysis, Saarland University, P.O. Box 151150, 66041 Saarbrücken, Germany.
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24
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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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25
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Geiser L, Mirgaldi M, Veuthey JL. Determination of electroosmotic flow in nonaqueous capillary electrophoresis. J Chromatogr A 2005; 1068:75-81. [PMID: 15844544 DOI: 10.1016/j.chroma.2005.02.001] [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] [Indexed: 11/20/2022]
Abstract
Mobility of the electroosmotic flow (mu(EOF)) in fused-silica capillaries strongly depends on the nature of the background electrolyte. In this study, 27 solvent systems were investigated, namely water, methanol, ethanol, 2-propanol, 1-butanol, acetonitrile (MeCN), formamide, N-methylformamide (NMF), N,N-dimethylformamide and dimethyl sulfoxyde, as well as 8 hydroorganic and 9 organic mixtures. For each system, six mu(EOF) were determined at a different ionic strength in basic conditions, and an absolute electroosmotic flow mobility (mu(EOF,0)) was extrapolated according to the Debye-Huckel Onsager model. The obtained mu(EOF,0) values were correlated with the solvent's relative permittivity (epsilon) and viscosity (eta). A good correlation (r2=0.867) between mu(EOF,0) and the solvent's epsilon/eta ratio was demonstrated, except for two solvents (MeCN and NMF). Furthermore, the donor number (DN) of a solvent took into account the possible zeta potential modification in the electric double layer near the capillary wall. Consequently, the relationship between mu(EOF,0) and epsilon/(eta x DN) was superior, with a r2 of 0.943 for 10 pure solvents.
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Affiliation(s)
- Laurent Geiser
- Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmacy, University of Geneva, Boulevard d'Yvoy 20, 1211 Geneva 4, Switzerland
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26
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Anderson MS, Lu B, Abdel-Rehim M, Blomberg S, Blomberg LG. Utility of nonaqueous capillary electrophoresis for the determination of lidocaine and its metabolites in human plasma: a comparison of ultraviolet and mass spectrometric detection. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2004; 18:2612-2618. [PMID: 15481095 DOI: 10.1002/rcm.1666] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A nonaqueous capillary electrophoresis/electrospray mass spectrometry method for the separation of lidocaine (LID) and two of its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), has been developed. The separation medium was: 70 mM ammonium formate and 2.0 M formic acid in acetonitrile/methanol (60:40 v/v). With a sheath liquid of methanol/water (80:20 v/v) containing 2% formic acid and positive ion detection, reproducible determinations (8-11% relative standard deviation (RSD)) of lidocaine and its metabolites were performed in spiked human plasma. The limits of detection (LODs) were between 69.1 and 337 nM. The influences of sheath liquid composition, nebulizing gas pressure and drying gas temperature on the separation were examined.
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Affiliation(s)
- Magnus S Anderson
- Department of Chemistry, Karlstad University, SE-651 88 Karlstad, Sweden
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27
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Cottet H, Vayaboury W, Kirby D, Giani O, Taillades J, Schué F. Nonaqueous Capillary Zone Electrophoresis of Synthetic Organic Polypeptides. Anal Chem 2003; 75:5554-60. [PMID: 14710838 DOI: 10.1021/ac034526o] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Poly(Nepsilon-trifluoroacetyl-L-lysine) was used as a model solute to investigate the potential of nonaqueous capillary electrophoresis (NACE) for the characterization of synthetic organic polymers. The information obtained by NACE was compared to that derived from size exclusion chromatography (SEC) experiments, and the two techniques were found to be complimentary for polymer characterization. On one hand, NACE permitted (i) the separation of oligomers according to their molar mass and (ii) the separation of the polymers according to the nature of the end groups. On the other hand, SEC experiments were used for the characterization of the molar mass distribution for higher molar masses. Due to the tendency of the solutes (polypeptides) to adsorb onto the fused-silica capillary wall, careful attention was paid to the rinsing procedure of the capillary between runs in order to keep the capillary surface clean. For that purpose, the use of electrophoretic desorption under denaturating conditions was very effective. Optimization of the separation was performed by studying (i) the influence of the proportion of methanol in a methanoVacetonitrile mixture and (ii) the influence of acetic acid concentration in the background electrolyte. Highly resolved separation of the oligomers (up to a degree of polymerization n of approximately 50) was obtained by adding trifluoroacetic acid to the electrolyte. Important information concerning the polymer conformations could be obtained from the mobility data. Two different plots relating the effective mobility data to the degree of polymerization were proposed for monitoring the changes in polymer conformations as a function of the number of monomers.
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Affiliation(s)
- Hervé Cottet
- Laboratoire Organisation Moléculaire, Evolution et Matériaux Fluorés, UMR CNRS 5073, Université de Montpellier II, case courier 17, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
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28
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Zhou Q, Liu J, Cai Y, Liu G, Jiang G. Micro-porous membrane liquid–liquid extraction as an enrichment step prior to nonaqueous capillary electrophoresis determination of sulfonylurea herbicides. Microchem J 2003. [DOI: 10.1016/s0026-265x(03)00003-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Kanitsar K, Chen Z, Owens G, Naidu R. Influence of Organic Modifiers on the Separation of Carboxylic Acids Using Co‐EOF Capillary Electrophoresis. J LIQ CHROMATOGR R T 2003. [DOI: 10.1081/jlc-120017182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Katherina Kanitsar
- a Institute of Chemistry, University of Agricultural Sciences‐BOKU Wien , Vienna , Austria
| | - ZuLiang Chen
- b CSIRO Land and Water , Adelaide Laboratory , 2 PMB, Glen Osmond , SA , 5064 , Australia
| | - Gary Owens
- b CSIRO Land and Water , Adelaide Laboratory , 2 PMB, Glen Osmond , SA , 5064 , Australia
| | - Ravendra Naidu
- b CSIRO Land and Water , Adelaide Laboratory , 2 PMB, Glen Osmond , SA , 5064 , Australia
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30
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Hedeland Y, Hedeland M, Bondesson U, Pettersson C. Chiral separation of amines with N-benzoxycarbonylglycyl-L-proline as selector in non-aqueous capillary electrophoresis using methanol and 1,2-dichloroethane in the background electrolyte. J Chromatogr A 2003; 984:261-71. [PMID: 12564698 DOI: 10.1016/s0021-9673(02)01869-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
N-Benzoxycarbonylglycyl-L-proline (L-ZGP) has been introduced as a chiral selector for enantioseparation of amines in non-aqueous capillary electrophoresis. Methanol mixed with different proportions of dichloromethane, 1,2-dichloroethane or 2-propanol containing L-ZGP and ammonium acetate was used as the background electrolyte. Enantioseparation of different types of pharmacologically active amines was performed, e.g. the local anaesthetic bupivacaine and the beta-adrenoceptor blocking agent pindolol. Addition of the solvents (dichloromethane, 1,2-dichloroethane or 2-propanol) gave an improved chiral separation partly due to a distinct decrease in the electroosmotic flow. The use of 1,2-dichloroethane in the background electrolyte gave higher precision in migration time (RSD 2.2%) compared to the systems containing dichloromethane. An enantiomeric separation of mepivacaine was performed within 72 s by use of short-end injection with an effective capillary length of 8.5 cm.
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Affiliation(s)
- Ylva Hedeland
- Division of Analytical Pharmaceutical Chemistry, Biomedical Centre, Uppsala University, Box 574, SE- 751 23 Uppsala, Sweden
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31
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Vuorensola K, Sirén H, Kostiainen R, Kotiaho T. Analysis of catecholamines by capillary electrophoresis and capillary electrophoresis-nanospray mass spectrometry. Use of aqueous and non-aqueous solutions compared with physical parameters. J Chromatogr A 2002; 979:179-89. [PMID: 12498247 DOI: 10.1016/s0021-9673(02)01256-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Catecholamines were analysed in aqueous and alcoholic non-aqueous solutions by capillary electrophoresis and capillary electrophoresis-mass spectrometry using sheathless nanospray coupling. Decreases in the electrophoretic mobilities of the catecholamines and in the electroosmotic mobilities were observed from water to 1-propanol. Separations were more efficient in all non-aqueous media than in water. The diffusion coefficients of the catecholamines in the different media were determined. The solvent had little effect on the sensitivity of the UV or MS detection. Both methods were successfully applied to the analysis of urine samples.
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Affiliation(s)
- Katariina Vuorensola
- University of Helsinki, Department of Pharmacy, Viikki Drug Discovery Technology Center (DDTC), P.O. Box 56, FIN-00014 Helsinki, Finland
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33
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Belder D, Husmann H, Warnke J. Directed control of electroosmotic flow in nonaqueous electrolytes using poly(ethylene glycol) coated capillaries. Electrophoresis 2001; 22:666-72. [PMID: 11296921 DOI: 10.1002/1522-2683(200102)22:4<666::aid-elps666>3.0.co;2-o] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Poly(ethylene glycol) (PEG)-coated capillaries exhibit unique properties in nonaqueous electrolytes. Immobilized PEG interacts significantly with different cations present in nonaqueous electrolytes. This can induce a positive surface charge on PEG-coated capillaries and results in an adjustable anodic electroosmotic flow (EOF) in nonaqueous electrolytes whereas a reduced cathodic EOF is observed in aqueous electrolytes. The EOF can reversibly be adjusted by the variation of the electrolyte constitution, namely the type of the solvent used and the nature and concentration of background cations. In methanol and especially in acetonitrile electrolytes the magnitude and also the direction of EOF is strongly dependent on the water content. Using different alkali metal cations, the EOF can be increased, reduced, or even reversed depending on the nature of the cation. The directed manipulation of EOF in methanolic electrolytes using PEG-coated capillaries was applied for optimization of nonaqueous capillary electrophoretic separations of acidic compounds with regard to reproducibility, resolution, and analysis time.
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Affiliation(s)
- D Belder
- Max-Planck-Institut für Kohlenforschung, Mülheim a.d.Ruhr, Germany.
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34
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Yang LL, Zhang DQ, Yuan ZB. Enantioseparation of o-phthaldiadehyde derivatized amino acids using β-CD-modified micellar electrokinetic chromatography in the mixed aqueous-organic media. Anal Chim Acta 2001. [DOI: 10.1016/s0003-2670(00)01212-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Abstract
Nonaqueous capillary electrophoresis (NACE) is the application of a conductive electrolyte dissolved in either one organic solvent or a mixture of several organic solvents to carry out zone electrophoresis or related techniques in fused-silica capillaries. A complete review on the fundamentals, the optimization of analytical methods, practical considerations, and applications is given. To explain the differences to CE in aqueous media, a brief summary on solvent properties and molecular interactions in solutions introduces the reader into these fields. The use of additives to tune separation selectivity by means beyond a pure zone-electrophoretic mechanism is discussed in detail for organic media. Special detection techniques providing high potential for NACE are presented. Data on the precision of NACE methods and a list of relevant applications are included. More specialized applications like the determination of physicochemical constants in NACE or the setup of a semipreparative mode are described.
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Affiliation(s)
- F Steiner
- University of the Saarland, Instrumental/Environmental Analysis, Saarbrücken, Germany.
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36
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Morales S, Cela R. Highly selective and efficient determination of US Environmental Protection Agency priority phenols employing solid-phase extraction and non-aqueous capillary electrophoresis. J Chromatogr A 2000; 896:95-104. [PMID: 11093644 DOI: 10.1016/s0021-9673(00)00581-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Non-aqueous capillary electrophoresis has been used in the separation of a complete list of 26 priority phenols included in the 8041 US Environmental Protection Agency method and the 76/464/EEC European Union directive. A highly selective and efficient separation was obtained when the background electrolyte used was 150 mM ammonium acetate dissolved in N-methylformamide-acetonitrile (75:25). Solid-phase extraction was successfully assayed as an enrichment strategy for the analysis of low-concentration samples. A styrene-divinylbenzene functionalized cartridge provided excellent recoveries of phenols from water samples at neutral pH. The limits of quantification obtained permit the application of the proposed method to the determination of priority phenols in wastewater samples.
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Affiliation(s)
- S Morales
- Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de Santiago de Compostela, Spain
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37
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Belder D, Elke K, Husmann H. Influence of pH*-value of methanolic electrolytes on electroosmotic flow in hydrophilic coated capillaries. J Chromatogr A 2000; 868:63-71. [PMID: 10677080 DOI: 10.1016/s0021-9673(99)01165-6] [Citation(s) in RCA: 24] [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
The dependency of EOF on the H+-concentration and the related so called pH* value of methanolic electrolytes has been examined with poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA) and uncoated capillaries. These results were compared with the pH dependency of EOF of these capillaries using aqueous buffers. In uncoated capillaries the dependency of EOF on the pH(*)-value is very similar for aqueous and methanolic electrolytes. The EOF increases with increasing H+-concentration and pH-hysteresis is observed. In PVA coated capillaries the EOF is strongly reduced over wide pH* or pH ranges for both methanolic electrolytes and aqueous buffers. The EOF in PEG coated capillaries is surprisingly directed to the anode with methanolic electrolytes whereas a reduced cathodic EOF is observed in aqueous electrolytes. The anodic EOF of PEG-coated capillaries in methanolic electrolytes is independent of the pH*-value. The usefulness of PEG- and PVA-coated capillaries for adjusting the EOF in non-aqueous electrolytes for the analysis of isomeric organic acids was demonstrated.
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Affiliation(s)
- D Belder
- Abteilung für Chromatographie, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany.
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38
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Wang R, Lu X, Xin H, Wu M. Separation of phenothiazines in aqueous and non-aqueous capillary electrophoresis. Chromatographia 2000. [DOI: 10.1007/bf02490692] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Karbaum A, Jira T. Nonaqueous capillary electrophoresis: application possibilities and suitability of various solvents for the separation of basic analytes. Electrophoresis 1999; 20:3396-401. [PMID: 10608706 DOI: 10.1002/(sici)1522-2683(19991101)20:17<3396::aid-elps3396>3.0.co;2-f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eleven organic solvents were tested for their suitability in the use of capillary electrophoresis (CE). In all cases, 25 mM ammonium acetate and 1 M acetic acid were used as electrolytes. Three basic therapeutical agents, propranolol, carteolol and imipramine, were used as analytes. Four solvents (2-propanol, ethylene glycol, propylene glycol, dichloromethane) were not suitable for use with CE under our conditions. Depending on the other solvents used, the analytes showed very different behavior. We observed that the epsilon/eta quotient alone is not sufficient for a characterization of the solvents. Further investigations with all the solvents as 1:1 mixtures with methanol were carried out. As a result some principal changes occurred compared to the pure solvents. Working with mixtures of different solvents proved to be advantageous because of the possibility to influence properties like high viscosity or low ionizing abilities by the addition of a suitable second solvent.
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Affiliation(s)
- A Karbaum
- Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry, Ernst-Moritz-Arndt-University Greifswald, Germany
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40
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Abstract
This review gives a survey of selectivity modes in capillary electrophoresis separations in pharmaceutical analysis and bioanalysis. Despite the high efficiencies of these separation techniques, good selectivity is required to allow quantitation or identification of a particular analyte. Selectivity in capillary electrophoresis is defined and described for different separation mechanisms, which are divided into two major areas: (i) capillary zone electrophoresis and (ii) electrokinetic chromatography. The first area describes aqueous (with or without organic modifiers) and nonaqueous modes. The second area discusses all capillary electrophoretic separation modes in which interaction with a (pseudo)stationary phase results in a change in migration rate of the analytes. These can be divided in micellar electrokinetic chromatography and capillary electrochromatography. The latter category can range from fully packed capillaries, via open-tubular coated capillaries to the addition of microparticles with multiple or single binding sites. Furthermore, an attempt is made to differentiate between methods in which molecular recognition plays a predominant role and methods in which the selectivity depends on overall differences in physicochemical properties between the analytes. The calculation of the resolution for the different separation modes and the requirements for qualitative and quantitative analysis are discussed. It is anticipated that selectivity tuning is easier in separation modes in which molecular recognition plays a role. However, sufficient attention needs to be paid to the efficiency of the system in that it not only affects resolution but also detectability of the analyte of interest.
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Affiliation(s)
- T de Boer
- Department of Analytical Chemistry and Toxicology, University Center for Pharmacy, Groningen, The Netherlands.
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41
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Peyrin E, Guillaume YC. Chemometric approach to the treatment of benzodiazepine separation and peak broadening in capillary electrophoresis. J Chromatogr A 1999; 849:563-73. [PMID: 10457451 DOI: 10.1016/s0021-9673(99)00596-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A chemometric methodology was used to study capillary efficiency and the separation of ten benzodiazepines in capillary electrophoresis. The resolution between two adjacent peaks on the electropherogram was estimated and the overall quality of the separation was assessed by means of a new response function. The nature (methanol or acetonitrile) and proportion of the organic modifier both in the background electrolyte and the sample buffer and the injection time were considered. The results predicted that if the sample had a lower dielectric constant than the background electrolyte buffer then a much larger injection volume could be used. The computer optimization routine was experimentally validated and the result demonstrated that the fastest electrophoretic reparation was obtained with acetonitrile (7 min instead of 9 min with methanol).
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Affiliation(s)
- E Peyrin
- Laboratoire de Chimie Analytique, Faculté de Médecine-Pharmacie, Besançon, France
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42
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Fillet M, Bechet I, Piette V, Crommen J. Separation of nonsteroidal anti-inflammatory drugs by capillary electrophoresis using nonaqueous electrolytes. Electrophoresis 1999; 20:1907-15. [PMID: 10445335 DOI: 10.1002/(sici)1522-2683(19990701)20:9<1907::aid-elps1907>3.0.co;2-l] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aim of the present work was to investigate the separation of nonsteroidal anti-inflammatory drugs (NSAIDs: niflumic acid, flufenamic acid, piroxicam, alclofenac, tiaprofenic acid, flurbiprofen, suprofen, ketoprofen, naproxen, indomethacin, carprofen, indoprofen, sulindac) in capillary electrophoresis (CE) using completely nonaqueous systems. The influence of different parameters such as nature and proportion of organic solvent (methanol, acetonitrile, 2-propanol), apparent pH (ranging from 7 to 9) and temperature (ranging from 25 to 40 degrees C) on selectivity and migration times were studied systematically in an uncoated fused-silica capillary. A nonaqueous electrolyte made of 50 mM ammonium acetate - 13.75 mM ammonia in methanol proved to resolve 11 NSAIDs at 25 degrees C and 13 NSAIDs at 36 degrees C, both within 13 min and without a modifier besides the methanol itself. The same buffer containing 30% acetonitrile provides a satisfactory separation for 13 NSAIDs within 14 min at 25 degrees C.
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Affiliation(s)
- M Fillet
- Department of Analytical, Pharmaceutical Chemistry, Institute of Pharmacy, University of Liège, Belgium.
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43
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Morales S, Cela R. Capillary electrophoresis and sample stacking in non-aqueous media for the analysis of priority pollutant phenols. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(98)01086-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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44
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Morin P, Daguet D, Coı̈c J, Dreux M. Usefulness of methylated-β-cyclodextrin-based buffers for the separation of highly hydrophobic solutes in non-aqueous capillary electrophoresis. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00106-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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45
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Tjørnelund J, Hansen SH. Non-aqueous capillary electrophoresis of drugs: properties and application of selected solvents. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1999; 38:139-53. [PMID: 10075269 DOI: 10.1016/s0165-022x(98)00034-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The electrophoretic mobility of selected acidic and basic test solutes have been determined in non-aqueous media prepared by adding various combinations of ammonium acetate, sodium acetate, methane sulphonic acid and acetic acid to acetonitrile, propylene carbonate, methanol, formamide, N-methylformamide, N,N-dimethylformamide and dimethylsulphoxide, respectively. The apparent pH (pH*) of these non-aqueous media have been measured and it was found that pH* is an important factor for the separations in non-aqueous capillary electrophoresis. However, in some solvents the concentration of sodium acetate has a strong influence on the mobility despite very small changes in pH*. Due to the fact that a change in one parameter influences a number of other parameters it is very difficult to conduct systematic studies in non-aqueous media and to compare the migration of the species at fixed pH* values from one solvent to another. Thus pH* is only of value for comparison when used with a specific solvent or solvent mixture. The viscosity of the above-mentioned solvents were measured at various temperatures and means to adjust the viscosity of the non-aqueous media used for capillary electrophoresis are discussed and the separation of ibuprofen and its major metabolites in urine is used as an example.
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Affiliation(s)
- J Tjørnelund
- Department of Analytical and Pharmaceutical Chemistry, Royal Danish School of Pharmacy, Copenhagen.
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46
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Porras SP, Valkó IE, Jyske P, Riekkola ML. Effect of electrolyte and solvent composition on capillary electrophoretic separation of some pharmaceuticals in non-aqueous media. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1999; 38:89-102. [PMID: 10075266 DOI: 10.1016/s0165-022x(98)00031-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Non-aqueous capillary electrophoresis was used to study the separation selectivity of positively charged drug substances and negatively charged diuretics. Study was made of the effects of organic solvent composition and the background electrolyte on the separation. The separation selectivity could be altered considerably by varying the methanol/acetonitrile composition. In addition, the migration order and the resolution of the pharmaceuticals could be altered merely by changing the electrolyte cation or the anion. The electrolytes tested were alkali metal acetates, ammonium acetate, ammonium chloride and ammonium bromide. As with aqueous background electrolyte solutions, the electroosmotic flow was decreased with increasing size of the alkali metal cation of the electrolyte in methanol/acetonitrile 50:50 (v/v).
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Affiliation(s)
- S P Porras
- Department of Chemistry, University of Helsinki, Finland
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47
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Nonaqueous capillary electrophoresis for the analysis of labile pharmaceutical compounds. Chromatographia 1999. [DOI: 10.1007/bf02468970] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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48
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Abstract
For the separation of neutral compounds by micellar electrokinetic chromatography, separations are usually carried out in predominantly aqueous solution in order to preserve the charged micelle necessary for the separation. We now show that polycyclic aromatic hydrocarbon (PAH) compounds can be separated efficiently by capillary electrophoresis in pure methanol or in aqueous-organic mixtures containing a high percentage of methanol. Sodium tetradecyl sulfate was the preferred surfactant. The effects of pH, solvent composition, surfactant structure, and surfactant concentration on the separations were studied. Reproducible migration times and linear calibration plots were obtained.
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Affiliation(s)
- J Li
- Department of Chemistry and Ames Laboratory, Iowa State University, 50011, USA
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49
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Thibon VRA, Bartle KD, Abbott DJ, Mccormack KA. Analysis of zinc dialkyl dithiophosphates by nonaqueous capillary electrophoresis and application to lubricants. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1520-667x(1999)11:1<71::aid-mcs9>3.0.co;2-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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50
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Valk� IE, Sir�n H, Riekkola ML. Characteristics of electroosmotic flow in capillary electrophoresis in water and in organic solvents without added ionic species. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1520-667x(1999)11:3<199::aid-mcs5>3.0.co;2-d] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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