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Blackney DM, Foley JP. Dual-opposite injection capillary electrophoresis: Principles and misconceptions. Electrophoresis 2016; 38:607-616. [PMID: 27859385 DOI: 10.1002/elps.201600337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/02/2016] [Accepted: 10/31/2016] [Indexed: 12/12/2022]
Abstract
Dual-opposite injection capillary electrophoresis (DOI-CE) is a separation technique that utilizes both ends of the capillary for sample introduction. The electroosmotic flow (EOF) is suppressed to allow all ions to reach the detector quickly. Depending on the individual electrophoretic mobilities of the analytes of interest and the effective length that each analyte travels to the detection window, the elution order of analytes in a DOI-CE separation can vary widely. This review discusses the principles, applications, and limitations of dual-opposite injection capillary electrophoresis. Common misconceptions regarding DOI-CE are clarified.
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Affiliation(s)
- Donna M Blackney
- Department of Chemistry, Drexel University, Philadelphia, PA, USA
| | - Joe P Foley
- Department of Chemistry, Drexel University, Philadelphia, PA, USA
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2
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Blackney DM, Foley JP. A systematic approach for avoiding co-detection of oppositely charged analytes in dual-opposite-injection capillary electrophoresis. J Chromatogr A 2015; 1395:180-9. [DOI: 10.1016/j.chroma.2015.03.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/27/2022]
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3
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Sáiz J, Duc MT, Koenka IJ, Martín-Alberca C, Hauser PC, García-Ruiz C. Concurrent determination of anions and cations in consumer fireworks with a portable dual-capillary electrophoresis system. J Chromatogr A 2014; 1372C:245-252. [PMID: 25465022 DOI: 10.1016/j.chroma.2014.10.085] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/20/2014] [Accepted: 10/27/2014] [Indexed: 11/27/2022]
Abstract
A new automated portable dual-channel capillary electrophoresis instrument was built and applied to the concurrent determination of cations and anions. The system uses a single buffer and hydrodynamic injection of the sample is performed autonomously. A novel engraved flow-cell interface is used at the injection ends of the capillaries allowing the autonomous operation of the system. The engraved flow-cell replaces traditionally used split injectors in purpose made capillary electrophoresis systems and makes the system design easier. A new software package with graphical user interface was employed to control the system, making its operation simple and increasing its versatility. The electrophoretic method was optimized to allow the baseline separation of 12 cations and anions commonly found in fireworks. The system was proven to be useful for the analysis of consumer fireworks, saving time and expenses compared to separate analyses for anions and cations. This is the first time that cationic and anionic compositions of fireworks are investigated together. The analysis of samples revealed several inaccuracies between the declared compositions for the fireworks and the obtained results, which could be attributed to cross-contamination during their manufacture or to a transfer between other components of the pyrotechnic item. The presence of certain unexpected peaks, however, had no apparent reason and might represent an irregularity in the manufacture of some devices.
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Affiliation(s)
- Jorge Sáiz
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain
| | - Mai Thanh Duc
- Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi, Viet Nam
| | - Israel Joel Koenka
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Carlos Martín-Alberca
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain
| | - Peter C Hauser
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Switzerland.
| | - Carmen García-Ruiz
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain; University Institute of Research in Police Sciences (IUICP), University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, 28871 Alcalá de Henares, Madrid, Spain.
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4
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Sáiz J, Koenka IJ, Mai TD, Hauser PC, García-Ruiz C. Simultaneous separation of cations and anions in capillary electrophoresis. Trends Analyt Chem 2014. [DOI: 10.1016/j.trac.2014.07.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Kubáň P, Greguš M, Pokojová E, Skřičková J, Foret F. Double opposite end injection capillary electrophoresis with contactless conductometric detection for simultaneous determination of chloride, sodium and potassium in cystic fibrosis diagnosis. J Chromatogr A 2014; 1358:293-8. [DOI: 10.1016/j.chroma.2014.06.091] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/25/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
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6
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Wei SY, Wang LF, Yang YH, Yeh HH, Chen YC, Chen SH. Sample stacking by field-amplified sample injection and sweeping for simultaneous analysis of acidic and basic components in clinic application. Electrophoresis 2012; 33:1571-81. [DOI: 10.1002/elps.201100716] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shao-Yun Wei
- School of Pharmacy; College of Pharmacy; Kaohsiung Medical University; Kaohsiung; Taiwan
| | - Li-Fang Wang
- Department of Medicinal and Applied Chemistry; Kaohsiung Medical University; Kaohsiung; Taiwan
| | - Yuan-Han Yang
- Department of Neurology; Kaohsiung Medical University Hospital; Kaohsiung; Taiwan
| | - Hsin-Hua Yeh
- School of Pharmacy; College of Pharmacy; Kaohsiung Medical University; Kaohsiung; Taiwan
| | - Yi-Chin Chen
- School of Nursing; College of Nursing; Kaohsiung Medical University; Kaohsiung; Taiwan
| | - Su-Hwei Chen
- School of Pharmacy; College of Pharmacy; Kaohsiung Medical University; Kaohsiung; Taiwan
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7
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Reschke BR, Schiffbauer J, Edwards BF, Timperman AT. Simultaneous separation and detection of cations and anions on a microfluidic device with suppressed electroosmotic flow and a single injection point. Analyst 2010; 135:1351-9. [DOI: 10.1039/b921914e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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TAKAYANAGI T, IKUTA A, MOTOMIZU S. Weak Binding of N-Alkylpyridinium Ions to Nonionic Surfactant Micelles as Studied by Capillary Zone Electrophoresis. ANAL SCI 2010; 26:625-7. [DOI: 10.2116/analsci.26.625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Toshio TAKAYANAGI
- Department of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University
| | - Ayumi IKUTA
- Department of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University
| | - Shoji MOTOMIZU
- Department of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University
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9
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White CM, Luo R, Archer-Hartmann SA, Holland LA. Electrophoretic screening of ligands under suppressed EOF with an inert phospholipid coating. Electrophoresis 2007; 28:3049-55. [PMID: 17665372 DOI: 10.1002/elps.200600816] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The applicability of dual injection CE for affinity selection of biopolymers that contain multiple binding sites is demonstrated. The efficient analysis of biomolecules such as carbohydrates and proteins, as well as pharmaceuticals by CE requires the reduction or elimination of nonspecific interactions with the capillary surface. Phospholipids are integral components of cell membranes and aqueous phospholipid liquid crystals adopt a bilayer structure on fused-silica. This phospholipid surface does not interact significantly with the following biomolecules: serum albumin, the 96-110 heparin binding domain of amyloid precursor protein (APP), polydisperse glycosaminoglycans, and variable chain-length oligosaccharides. Pharmaceuticals including five anionic nonsteroidal anti-inflammatory drugs, three cationic analgesics, and two cationic beta-blockers, also show minimal interaction with the surface. In addition, the use of a phospholipid coating suppresses EOF, which enables reversed-polarity separations, dual opposite injection CE, affinity screening via CE by dual opposite injection, and serial target-ligand injections.
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Affiliation(s)
- Christian M White
- C. Eugene Bennett, Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
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10
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Weekley BS, Foley JP. Dual-opposite-injection CZE: Theoretical aspects and application to organic and pharmaceutical compounds. Electrophoresis 2007; 28:697-711. [PMID: 17253631 DOI: 10.1002/elps.200600608] [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: 11/08/2022]
Abstract
Several important figures of merit (migration time, efficiency, resolution, resolution per unit time, and electrophoretic selectivity) are quantitatively compared for the first time for conventional CZE and dual-opposite-injection CZE (DOI-CZE). Aspects of DOI-CZE relevant to the separation of organic and pharmaceutical ions (MW>120 Da) are also discussed. Two new approaches to resolve the codetection of anions and cations, hydrodynamic flow-modified DOI-CZE and polarity reversal in combination with asymmetric detector window positioning, are compared with the method of preliminary transport, a variable procedure within sequential sample introduction, using a six-component sample of organic and pharmaceutical compounds. The advantages of DOI-CZE for the simultaneous analysis of organic/pharmaceutical anions and cations are illustrated in a direct comparison of conventional CZE and DOI-CZE for the separation of a ten-component mixture of pharmaceutical ions (five ionized acids and five ionized bases).
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Affiliation(s)
- Brian S Weekley
- Analytical R&D, Pfizer Global Research and Development, Ann Arbor, MI, USA
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11
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Priego-Capote F, Luque de Castro MD. Dual-opposite injection capillary electrophoresis for the determination of anionic and cationic homologous surfactants in a single run. Electrophoresis 2005; 26:2283-92. [PMID: 15920780 DOI: 10.1002/elps.200500053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An electrophoretic method for the simultaneous separation and determination of cationic and anionic surfactants based on double electrokinetic injection from the two ends of the capillary is proposed here. Nonaqueous capillary electrophoresis (NACE) with methanol as solvent was used to reduce the electroosmotic flow so that under these conditions the analytes migrate toward the corresponding electrode. The optimization step was the key to solve the problems associated with surfactants analysis (namely, adsorption on the capillary wall, micelle formation, and those issues related to the separation of homologous compounds). Good results were obtained with the proposed method both for the analysis of both spiked and natural samples, thus demonstrating the applicability of the proposed method for routine analysis. Finally, a comparison between the proposed method and two methods for independent analysis of cationic and anionic surfactants was made. The results showed that the precision (between 1.90 and 4.10% for repeatability and 7.43 and 8.98% for within-laboratory reproducibility, both expressed as relative standard deviation) and sensitivity (limits of detection and quantification between 0.52 and 1.88 microg/mL and between 1.73 and 6.20 microg/mL, respectively) are not affected by the CE mode. The resolution was similar to or better than that of the comparison methods and the analysis time was considerably shortened as both types of compounds were determined in a single run in only 9 min.
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12
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Priego-Capote F, Luque de Castro MD. Dual injection capillary electrophoresis: Foundations and applications. Electrophoresis 2004; 25:4074-85. [PMID: 15597416 DOI: 10.1002/elps.200406135] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The state of the art of capillary electrophoresis (CE) approaches based on dual injection is here reported. Dual injection strategies have been proposed with three main objectives: (i) to provide information about reaction kinetics and/or related parameters, (ii) to perform in-capillary derivatization for improving separation and/or determination, (iii) to develop electrophoretic methods for the simultaneous analysis of anionic and cationic compounds. For the first two purposes, dual injection, which involves sample and reagent, can be realized either from the same end of the capillary (electrophoretically mediated microanalysis, EMMA) or from the two ends of the capillary (electroinjection analysis, EIA). The third objective, with dual injection of sample from the two ends of the capillary, takes advantage of moving cationic and anionic compounds with opposite directions. The foundations of each alternative, conditions necessary for working with them, restrictions, applications as well as perspectives are reviewed in order to establish the advantages, shortcomings, and convenience or no of their use in comparison to conventional CE.
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Tanyanyiwa J, Leuthardt S, Hauser PC. Electrophoretic separations with polyether ether ketone capillaries and capacitively coupled contactless conductivity detection. J Chromatogr A 2002; 978:205-11. [PMID: 12458956 DOI: 10.1016/s0021-9673(02)01425-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Polyether ether ketone (PEEK) capillaries were found to be compatible with capacitively-coupled contactless-conductivity detection (C4D). Detection limits in the order of 10(-7) M were obtained with C4D employing a high excitation voltage (HV-C4D) for inorganic cations and anions. The organic polymer capillary shows a relatively low electroosmotic flow of 2.6 x 10(-4) cm2 V(-1) s(-1). Thus inorganic anions and slower organic anions can be separated with a PEEK capillary in a single run without flow modifier. This feature also enables the analysis of both, cations and (fast and slow) anions, in a sample in two subsequent runs just by reversing the polarity or in a single run if dual opposite end injection is employed.
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Affiliation(s)
- Jatisai Tanyanyiwa
- University of Basel, Department of Chemistry, Spitalstrasse 51, 4004 Basel, Switzerland
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14
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Kubán P, Kubán P, Kubán V. Simultaneous determination of inorganic and organic anions, alkali, alkaline earth and transition metal cations by capillary electrophoresis with contactless conductometric detection. Electrophoresis 2002; 23:3725-34. [PMID: 12432535 DOI: 10.1002/1522-2683(200211)23:21<3725::aid-elps3725>3.0.co;2-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Simultaneous separation of up to 22 inorganic and organic anions, alkali, alkaline earth and transition metal cations was achieved in less than 3 min in the capillary electrophoresis system with contactless conductometric detector. The sample was injected from both capillary ends (dual opposite end injection) and anionic and cationic species were detected in the center of the separation capillary. The parameters of the separation electrolyte, such as pH, concentration of the electrolyte, concentration of complexing agents and concentration of 18-crown-6 were studied. Best results were achieved with electrolytes consisting of 8 mM L-histidine, 2.8 mM 2-hydroxyisobutyric acid, 0.32 mM 18-crown-6 at pH 4.25 or 9 mM L-histidine, 4.6 mM lactic acid, 0.38 mM 18-crown-6 at pH 4.25. Other electrolytes containing complexing agents such as malic or tartaric acid at various concentrations could also be used. The detection limits achieved for most cations and anions were 7.5 - 62 micro gL(-1) except for Ba2+ (90 micro gL(-1)), Cd 2+, Cr 3+ and F- (125 micro gL(-1)), and fumarate (250 micro gL(-1)). The repeatability of migration times and peak areas was better than 0.4% and 5.9%, respectively. The developed method was applied for analysis of real samples, such as tap, rain, drainage and surface water samples, plant exudates, plant extracts and ore leachates.
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Affiliation(s)
- Pavel Kubán
- Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Brno, Czech Republic
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15
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Kubán P, Karlberg B, Kubán P, Kubán V. Application of a contactless conductometric detector for the simultaneous determination of small anions and cations by capillary electrophoresis with dual-opposite end injection. J Chromatogr A 2002; 964:227-41. [PMID: 12198852 DOI: 10.1016/s0021-9673(02)00656-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A contactless conductometric detection (CCD) system for capillary electrophoresis (CE) with a flexible detection cell was applied for the simultaneous determination of small anions and/or cations in rain, surface and drainage water samples. The applied frequency, the amplitude of the input signal, the electrolyte conductivity and electrode distance were found to be the most significant factors affecting the detection sensitivity. 2-(N-Morpholino)ethanesulfonic acid/histidine-based (MES/His) electrolytes were used for direct conductivity detection of anions and cations, while ammonium acetate was selected for indirect conductivity determination of alkylammonium salts. For the simultaneous separation procedure, involving dual-opposite end injection, an electrolyte consisting of 20 mM MES/His, 1.5 mM 18-crown-6 and 20 microM cetyltrimethylammonium bromide provided baseline separation of 13 anions and cations in less than 6 min. The detection limits achieved were 7-30 micrograms/l for direct conductometric detection of various common inorganic cations and anions, excluding F- (62 micrograms/l) and H2PO4- (250 micrograms/l), and 35-178 micrograms/l for indirect conductometric detection of alkyl ammonium cations. The developed electrophoretic method with conductometric detection was compared to ion chromatography.
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Affiliation(s)
- Petr Kubán
- Department of Analytical Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
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16
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Badal MY, Wong M, Chiem N, Salimi-Moosavi H, Harrison DJ. Protein separation and surfactant control of electroosmotic flow in poly(dimethylsiloxane)-coated capillaries and microchips. J Chromatogr A 2002; 947:277-86. [PMID: 11883661 DOI: 10.1016/s0021-9673(01)01601-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A thermally pyrolyzed poly(dimethylsiloxane) (PDMS) coating intended to prevent surface adsorption during capillary electrophoretic (CE) [Science 222 (1983) 266] separation of proteins, and to provide a substrate for surfactant adsorption for electroosmotic mobility control was prepared and evaluated. Coating fused-silica capillaries or glass microchip CE devices with a 1% solution of 100 cSt silicone oil in CH2Cl2, followed by forced N2 drying and thermal curing at 400 degrees C for 30 min produced a cross-linked PDMS layer. Addition of 0.01 to 0.02% Brij 35 to a 0.020 M phosphate buffer gave separations of lysozyme, cytochrome c, RNase, and fluorescein-labeled goat anti-human IgG Fab fragment. Respective plates/m typically obtained at 20 kV (740 V cm(-1)) were 2, 1.5, 1.25, and 9.4-10(5). In 50 mM ionic strength phosphate, 0.01% Brij 35 running buffer, the electroosmotic flow observed was about 25% of that in a bare capillary, and showed no pH dependence between pH 6.3-8.2. Addition of sodium dodecylsulfate (SDS) or cetyltrimethylammonium bromide (CTAB) to this running buffer allowed ready control of electroosmotic mobility, mu(eo). Concentrations of SDS between 0.005 to 0.1% resulted in mu(eo) ranging from 3 to 5 x 10(-4) cm2 V(-1) s(-1). Addition of 1 to 2.3 x 10(-4)% (2.7-6.3 microM) CTAB caused flow reversal. CTAB concentrations between 3.5 x 10(-4) and 0.05% (0.0014-1.37 mM) allowed control of mu(eo) between -1 x 10(-4) and -5.0 x 10(-4) cm2 V(-1) s(-1). For both surfactants the added presence of 0.01% Brij 35 provided slowly varying changes in mu(eo) with charged surfactant concentration.
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Affiliation(s)
- M Youssouf Badal
- Department of Chemistry, University of Alberta, Edmonton, Canada
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17
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Wei W, Yeung ES. DNA capillary electrophoresis in entangled dynamic polymers of surfactant molecules. Anal Chem 2001; 73:1776-83. [PMID: 11338591 DOI: 10.1021/ac0012997] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aqueous solutions of monomeric nonionic surfactants, n-alkyl polyoxyethylene ethers (C16E6, C16E8, C14E6), can be used as sieving matrixes for the separation of DNA fragments by capillary electrophoresis. Unlike ordinary polymer solutions, these surfactant solutions behave as dynamic polymers. By combining the "reversible gel" theory of DNA electrophoresis and the static and dynamic properties of wormlike surfactant micelles, a model is developed for describing the migration behavior of DNA molecules in these solutions. According to the model, the separation limit can be extended at low surfactant concentrations. Surfactant solutions as a separation medium provide many advantages over ordinary polymers, such as ease of preparation, solution homogeneity, stable structure, low viscosity, and self-coating property for reducing electroosmotic flow. More importantly, the properties of wormlike micelles (micelle size, entanglement concentration) can be adjusted by simply changing the monomer concentration, denaturant, and temperature to allow the separation of different size ranges of DNA fragments. Fast separation is achieved for DNA fragments ranging from 10 bp to 5 kb by using bare fused-silica columns. DNA sequencing fragments of BigDye G-labeled M13 up to 600 bases were separated within 60 min.
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Affiliation(s)
- W Wei
- Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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Giordano BC, Copeland ER, Landers JP. Towards dynamic coating of glass microchip chambers for amplifying DNA via the polymerase chain reaction. Electrophoresis 2001; 22:334-40. [PMID: 11288902 DOI: 10.1002/1522-2683(200101)22:2<334::aid-elps334>3.0.co;2-o] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
As microchip technology evolves to allow for the integration of more complex processes, particularly the polymerase chain reaction (PCR), it will become necessary to define simple approaches for minimizing the effects of surfaces on the chemistry/processes to be performed. We have explored alternatives to silanization of the glass surface with the use of additives that either dynamically coat or adsorb to the glass surface. Polyethylene glycol, polyvinylpyrrolidone (PVP), and hydroxyethylcellulose (HEC) have been explored as potential dynamic coatings and epoxy (poly)dimethylacrylamide (EPDMA) evaluated as an adsorbed coating. By carrying out analysis of the PCR products generated under different conditions via microchip electrophoresis, we demonstrate that these coating agents adequately passivate the glass surface in a manner that prevents interference with the subsequent PCR process. While several of the agents tested allowed for PCR amplification of DNA in glass, the EPDMA was clearly superior with respect to ease of preparation. However, more efficient PCR (larger mass of amplified product) could be obtained by silanizing the glass surface.
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Affiliation(s)
- B C Giordano
- Department of Chemistry, University of Virginia, Charlottesville 22901, USA
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