1
|
Electroosmotic flow modulation for improved electrokinetic preconcentration: Application to capillary electrophoresis of fluorescent magnetic nanoparticles. Anal Chim Acta 2021; 1161:338466. [PMID: 33896565 DOI: 10.1016/j.aca.2021.338466] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/22/2021] [Accepted: 03/24/2021] [Indexed: 02/06/2023]
Abstract
It is reported in this study a new approach for modulation and even suppression of the electroosmotic flow (EOF) to achieve better electrokinetic preconcentration in capillary electrophoresis. This is based on the augmentation of the buffer's concentrations to very high levels (more than a thousand of mM) without recourse to any dynamic/permanent coating nor viscous gel. The use of large weakly charged molecules as background electrolyte's constituents allows working at extreme concentration ranges without penalty of high electric currents and Joule heating. By this way, the electroosmotic mobility could be modulated over a wide range (2-60 × 10-5 cm2 V-1 s-1 under alkaline conditions), and suppressed to levels equivalent to those obtained with several neutral coatings. The highest buffer concentrations, and the lowest EOF magnitudes, accordingly, were achieved with diethanolamine/3-(Cyclohexylamino)-1-propanesulfonic acid (ionic strength (IS) of 250 mM, pH 9.5), Tris(hydroxymethyl)aminomethane (Tris)/2-(Cyclohexylamino)ethanesulfonic acid (CHES) (IS of 280 mM, pH 8.7) and triethanolamine/2-(Cyclohexylamino)ethanesulfonic acid (IS of 250 mM, pH 8.5). For demonstration, this new approach was applied for sensitive determination of core-shell magnetic nanoparticles (CSMNPs) having high potential for healthcare applications such as imaging agents for diagnostics and controllable cargos for nanomedicine. Different profiles were achieved for purpose-made and commercial magnetic nanoparticles using CE coupled with light-emitting-diode induced fluorescence (LEDIF) detection. The best performance for EOF-assisted preconcentration and CE-LEDIF of CSMNPs was achieved with these nanoparticles prepared in TRIS/CHES (IS 10 mM, pH 8.4) for preconcentration, and separation under BGE of TRIS/CHES (IS 100 mM, pH 8.4). Compared to the conventional capillary electrophoresis (CE-UV) method for characterization of magnetic nanoparticles, our proposed approach with fluorescent detection and EOF-assisted preconcentration offers almost 350-fold sensitivity improvement. Furthermore, our scheme can be used for monitoring the interaction between CSMNPs and target pharmaceutical molecules, serving for drug delivery development. A preliminary study with two antibiotics using this approach revealed that kanamycin interacts better with the target nanoparticles than amikacin.
Collapse
|
2
|
El-Awady M, Pyell U. Processes involved in sweeping as sample enrichment method in cyclodextrin-modified micellar electrokinetic chromatography of hydrophobic basic analytes. Electrophoresis 2014; 35:605-16. [DOI: 10.1002/elps.201300259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 12/02/2013] [Accepted: 12/02/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Mohamed El-Awady
- Department of Chemistry; University of Marburg; Marburg Germany
- Faculty of Pharmacy; Department of Analytical Chemistry; Mansoura University; Mansoura Egypt
| | - Ute Pyell
- Department of Chemistry; University of Marburg; Marburg Germany
| |
Collapse
|
3
|
El-Awady M, Belal F, Pyell U. Robust analysis of the hydrophobic basic analytes loratadine and desloratadine in pharmaceutical preparations and biological fluids by sweeping—cyclodextrin-modified micellar electrokinetic chromatography. J Chromatogr A 2013; 1309:64-75. [DOI: 10.1016/j.chroma.2013.08.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/02/2013] [Accepted: 08/06/2013] [Indexed: 10/26/2022]
|
4
|
Guan Q, Noblitt SD, Henry CS. Electrophoretic separations in poly(dimethylsiloxane) microchips using a mixture of ionic and zwitterionic surfactants. Electrophoresis 2012; 33:379-87. [PMID: 22222982 PMCID: PMC3516918 DOI: 10.1002/elps.201100259] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The use of mixtures of ionic and zwitterionic surfactants in poly(dimethylsiloxane) (PDMS) microchips is reported. The effect of surfactant concentration on electroosmotic flow (EOF) was studied for a single anionic surfactant (sodium dodecyl sulfate, SDS), a single zwitterionic surfactant (N-tetradecylammonium-N,N-dimethyl-3-ammonio-1-propanesulfonate, TDAPS), and a mixed SDS/TDAPS surfactant system. SDS increased the EOF as reported previously while TDAPS showed an initial increase in EOF followed by a reduction at higher concentrations. When TDAPS was added to a solution containing SDS, the EOF decreased in a concentration-dependent manner. The EOF for all three surfactant systems followed expected pH trends, with increasing EOF at higher pH. The mixed surfactant system allowed tuning of the EOF across a range of pH and concentration conditions. After establishing the EOF behavior, the adsorption/desorption kinetics were measured and showed a slower adsorption/desorption rate for TDAPS than SDS. Finally, the separation and electrochemical detection of model catecholamines in buffer and reduced glutathione in red blood cell lysate using the mixed surfactant system were explored. The mixed surfactant system provided shorter analysis times and/or improved resolution when compared to the single surfactant systems.
Collapse
Affiliation(s)
- Qian Guan
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | | | | |
Collapse
|
5
|
Otieno AC, Quainoo EW, Mwongela SM. Metal cations for the determination of fluorescent phosphoinositides by capillary electrophoresis. J Sep Sci 2008; 31:3894-901. [DOI: 10.1002/jssc.200800412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
6
|
Yu L, Xu X, Huang L, Lin J, Chen G. Microemulsion electrokinetic chromatography coupling with field amplified sample injection and electroosmotic flow suppressant for analysis of some quinolizidine alkaloids. J Chromatogr A 2008; 1198-1199:220-5. [DOI: 10.1016/j.chroma.2008.05.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 05/10/2008] [Accepted: 05/14/2008] [Indexed: 11/28/2022]
|
7
|
Qu Q, Tang X, Mangelings D, Wang C, Yang G, Hu X, Yan C. Control of electroosmotic flow by a cation additive to enhance the separation of amino acids by micellar electrokinetic chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 853:31-7. [PMID: 17418648 DOI: 10.1016/j.jchromb.2007.02.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 01/03/2007] [Accepted: 02/23/2007] [Indexed: 10/23/2022]
Abstract
The effect of a divalent cation (Mg2+) and 3 monovalent cations (Na+, Li+, and K+) as buffer additives on the electroosmotic flow (EOF) was investigated in order to improve the separation performance of p-acetamidobenzenesulfonyl fluoride (PAABS-F) derivatives of 20 standard amino acids by micellar electrokinetic chromatography (MEKC). The EOF can be decreased with increasing concentration of cations with the order of cations as Mg2+>K+>Na+>Li+. However, it was found that the resolution cannot be improved easily using a buffer cation which is more capable of decreasing the EOF. Taking the migration time, resolution, and peak shape into account, Na+ is the best buffer additive, although the EOF decreased most using Mg2+. Using 20 mmol/L borate at pH 9.3 containing 140 mmol/L SDS and 20 mmol/L Na+ as electrolyte, 20 standard amino acids were successfully separated within 14 min.
Collapse
Affiliation(s)
- Qishu Qu
- Jiangsu Key Laboratory of Environmental Materials and Environmental Engineering, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
| | | | | | | | | | | | | |
Collapse
|
8
|
A new method to measure zeta potentials of microfabricated channels by applying a time-periodic electric field in a T-channel. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2006.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Soontornniyomkij† B, Scandrett K, Pietrzyk DJ. Capillary Zone Electrophoresis Separation of Amino Acid Enantiomers as Dansylated Derivatives Through Control of Electroosmotic Flow. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079808000536] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- B. Soontornniyomkij†
- a Ubon Ratchathani University, Department of Chemistry Warinchamrap , Ubon Ratchathani, 34190, Thailand
| | - K. Scandrett
- b University of Iowa, Department of Chemistry , Iowa City, IA, 52242
| | - D. J. Pietrzyk
- b University of Iowa, Department of Chemistry , Iowa City, IA, 52242
| |
Collapse
|
10
|
Soontornniyomkij† B, Chen S, Minnoor ES, Pietrzyk DJ. Application of an Electroosmotic Flow Gradient in Capillary Zone Electrophoresis Separations. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079808006879] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- B. Soontornniyomkij†
- a Ubon Ratchathani University Faculty of Science, Department of Chemistry Warinchamrab , Ubon Ratchathani, 34190, Thailand
| | - S. Chen
- a Ubon Ratchathani University Faculty of Science, Department of Chemistry Warinchamrab , Ubon Ratchathani, 34190, Thailand
| | - E. S. Minnoor
- a Ubon Ratchathani University Faculty of Science, Department of Chemistry Warinchamrab , Ubon Ratchathani, 34190, Thailand
| | - D. J. Pietrzyk
- b University of Iowa, Department of Chemistry Iowa City , Iowa, 52242, USA
| |
Collapse
|
11
|
Vrouwe EX, Luttge R, Olthuis W, van den Berg A. Rapid inorganic ion analysis using quantitative microchip capillary electrophoresis. J Chromatogr A 2006; 1102:287-93. [PMID: 16310794 DOI: 10.1016/j.chroma.2005.10.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 10/18/2005] [Accepted: 10/27/2005] [Indexed: 10/25/2022]
Abstract
Rapid quantitative microchip capillary electrophoresis (CE) for online monitoring of drinking water enabling inorganic ion separation in less than 15 s is presented. Comparing cationic and anionic standards at different concentrations the analysis of cationic species resulted in non-linear calibration curves. We interpret this effect as a variation in the volume of the injected sample plug caused by changes of the electroosmotic flow (EOF) due to the strong interaction of bivalent cations with the glass surface. This explanation is supported by the observation of severe peak tailing. Conducting microchip CE analysis in a glass microchannel, optimized conditions are received for the cationic species K+, Na+, Ca2+, Mg2+ using a background electrolyte consisting of 30 mmol/L histidine and 2-(N-morpholino)ethanesulfonic acid, containing 0.5 mmol/L potassium chloride to reduce surface interaction and 4 mmol/L tartaric acid as a complexing agent resulting in a pH-value of 5.8. Applying reversed EOF co-migration for the anionic species Cl-, SO42- and HCO3- optimized separation occurs in a background electrolyte consisting of 10 mmol/L 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and 10 mmol/L HEPES sodium salt, containing 0.05 mmol/L CTAB (cetyltrimethylammonium bromide) resulting in a pH-value of 7.5. The detection limits are 20 micromol/L for the monovalent cationic and anionic species and 10 micromol/L for the divalent species. These values make the method very suitable for many applications including the analysis of abundant ions in tap water as demonstrated in this paper.
Collapse
Affiliation(s)
- Elwin X Vrouwe
- BIOS The Lab-on-a-Chip Group, MESA(+) Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | |
Collapse
|
12
|
Abstract
The determination of the velocities of the mobile and the pseudostationary phases (the migration (time) window) is mandatory for the determination of physicochemical properties by electrokinetic chromatography (EKC). This review offers a detailed discussion on the definition, the importance, the determination and the regulation of the migration (time) window in EKC. An overview on the theoretical treatment of chromatographic processes in EKC is given defining EKC in comparison to the term capillary electrophoresis. Methods to determine and influence the migration window are discussed with emphasis on measures that have been taken to modify the electroosmotic flow velocity. Pseudostationary phases (or separation carriers) that are taken into consideration are anionic and cationic micelles, mixed micelles, microdroplets (microemulsions), polymeric pseudostationary phases and dendrimers.
Collapse
Affiliation(s)
- Ute Pyell
- Philipps- Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
| |
Collapse
|
13
|
Chapter 14 Chromatography of amino acids and peptides. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0301-4770(04)80027-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
14
|
Melanson JE, Baryla NE, Lucy CA. Dynamic capillary coatings for electroosmotic flow control in capillary electrophoresis. Trends Analyt Chem 2001. [DOI: 10.1016/s0165-9936(01)00067-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
15
|
Mikus P, Kaniansky D, Fanali S. Separation of multicomponent mixtures of 2,4-dinitrophenyl labelled amino acids and their enantiomers by capillary zone electrophoresis. Electrophoresis 2001; 22:470-7. [PMID: 11258757 DOI: 10.1002/1522-2683(200102)22:3<470::aid-elps470>3.0.co;2-g] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The use of capillary zone electrophoresis (CZE) for the separation of a group of 33 2,4-dinitrophenyl labeled amino acids (DNP-AA), including DNP-AA racemates, DNP-L-AA enantiomers and achiral DNP-AAs, was investigated. Alpha-, beta- and gamma-cyclodextrins (CDs) and their derivatives (hydroxypropyl derivatives of alpha-, beta- and gamma-CDs, polymeric beta-CD and 6A-methylamino-beta-cyclodextrin (MA-beta-CD)) served as complexing agents and chiral selectors in this investigation. Although native alpha- and gamma-CDs and their derivatives influenced the effective mobilities of the studied DNP-AAs in different ways, they generally failed to resolve enantiomers of the individual DNP-AAs. On the other hand, beta-CD and all of its derivatives were found to be effective in this respect. Of these, the best results were achieved with a positively charged MA-beta-CD and this chiral selector resolved enantiomers of ten DNP-AA racemates available for this study. However, a complete resolution of these enantiomers in one CZE run required that the effect of the chiral selector be complemented by complexing effects of polyvinyl pyrrolidone (PVP) or gamma-CD. Complexing and chiral recognition capabilities of MA-beta-CD combined with complexing effects of gamma-CD and PVP provided separating conditions suitable for the CZE separations of multicomponent mixtures of DNP-AAs with preserved resolutions of the enantiomers. For example, a mixture consisting of 43 DNP-AA constituents was resolved using an MA-beta-CD/gamma-CD combination with three peak overlaps.
Collapse
Affiliation(s)
- P Mikus
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic
| | | | | |
Collapse
|
16
|
He Y, Pang HM, Yeung ES. Integrated electroosmotically-driven on-line sample purification system for nanoliter DNA sequencing by capillary electrophoresis. J Chromatogr A 2000; 894:179-90. [PMID: 11100861 DOI: 10.1016/s0021-9673(00)00676-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
An integrated on-line system is developed for DNA sequencing at the nanoliter scale. The technique involves the use of a nanoreactor for small-volume cycle-sequencing reaction, capillary zone electrophoresis (CZE) for purification of the sequencing fragments, and capillary gel electrophoresis (CGE) for separation of the purified DNA fragments. The nanoreactor and CZE are integrated into one capillary, where a 100-nl dye-labeled terminator cycle-sequencing reaction is carried out followed by CZE to separate excess dye-labeled terminators from the sequencing fragments. On-line electrokinetic injection of the purified DNA fragments into the CGE system is accomplished at a small-volume tee connector by which the CZE capillary is interfaced to the CGE system. The utility of the system is demonstrated in sequencing nanoliter volumes of single-stranded DNA (M13mp18) and double-stranded DNA (pGEM). The use of voltage to drive both CZE and CGE makes it feasible for automation and future adaptation of the whole system to a microchip.
Collapse
Affiliation(s)
- Y He
- Ames Laboratory-US Department of Energy and Department of Chemistry, Iowa State University, 50011, USA
| | | | | |
Collapse
|
17
|
Minnoor E, Liu Y, Pietrzyk DJ. Applications of a sulfonated-polymer wall-modified open-tubular fused-silica capillary in capillary zone electrophoretic separations. J Chromatogr A 2000; 884:297-309. [PMID: 10917448 DOI: 10.1016/s0021-9673(00)00060-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A fused-silica capillary that is wall-modified via chemically bonding a sulfonated polymer to the capillary wall has a uniform negative charge density on its surface and produces an electroosmotic flow (EOF) greater than 4 x 10(-4) cm2 V(-1) s(-1) The EOF is nearly independent of buffer pH over the pH range of 2 to 10 and is lower than the EOF obtained for the bare fused-silica capillary at the more basic pH but is higher at the more acidic buffer pH. Optimization of buffer pH can be based on analyte pKa values to improve the overall quality of the capillary zone electrophoresis (CZE) separation of complex mixtures of weak acid and base analytes. Because of the high EOF in an acidic buffer, the capillary is useful for the separation of weak organic bases which are in their cation forms in the acidic buffer. EOF for the sulfonic acid bonded phase capillary can be adjusted via buffer additives such as organic solvent, tetraalkylammonium salts, multivalent cations and alkylsulfonic acids. The advantages of utilizing buffer pH and the EOF buffer modifiers to enhance migration time, selectivity, and resolution in CZE separations with this capillary are illustrated using a series of test analyte mixtures of inorganic anions, carboxylic acids, alkylsulfonic acids, benzenesulfonic acids, sulfas, pyridines, anilines or small-chain peptides.
Collapse
Affiliation(s)
- E Minnoor
- Universiry of Iowa, Department of Chemistry, Iowa City, 52242, USA
| | | | | |
Collapse
|
18
|
Dworschak A, Pyell U. Widening of the elution window in micellar electrokinetic chromatography with cationic surfactants. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00419-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
19
|
Application of capillary zone electrophoresis to the study of interactions betweenBacillus subtilis tryptophanyl-tRNA synthetase and tRNATrp. Chromatographia 1998. [DOI: 10.1007/bf02467682] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
20
|
Liu Y, Pietrzyk D. Separation of weak organic acids and bases by capillary zone electrophoresis in a sulfonated-polymer wall-modified open tubular fused-silica capillary. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00125-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|