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Microfluidic free-flow electrophoresis: a promising tool for protein purification and analysis in proteomics. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.02.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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2
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Sun L, Chen Q, Lu H, Wang J, Zhao J, Li P. Electrodialysis with porous membrane for bioproduct separation: Technology, features, and progress. Food Res Int 2020; 137:109343. [DOI: 10.1016/j.foodres.2020.109343] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 11/26/2022]
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3
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Anciaux SK, Bowser MT. Reduced surface adsorption in 3D printed acrylonitrile butadiene styrene micro free-flow electrophoresis devices. Electrophoresis 2020; 41:225-234. [PMID: 31816114 PMCID: PMC7316087 DOI: 10.1002/elps.201900179] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/27/2023]
Abstract
We have 3D printed and fabricated micro free-flow electrophoresis (µFFE) devices in acrylonitrile butadiene styrene (ABS) that exhibit minimal surface adsorption without requiring additional surface coatings or specialized buffer additives. 2D, nano LC-micro free flow electrophoresis (2D nLC × µFFE) separations were used to assess both spatial and temporal broadening as peaks eluted through the separation channel. Minimal broadening due to wall adsorption was observed in either the spatial or temporal dimensions during separations of rhodamine 110, rhodamine 123, and fluorescein. Surface adsorption was observed in separations of Chromeo P503 labeled myoglobin and cytochrome c but was significantly reduced compared to previously reported glass devices. Peak widths of < 30 s were observed for both proteins. For comparison, Chromeo P503 labeled myoglobin and cytochrome c adsorb strongly to the surface of glass µFFE devices resulting in peak widths >20 min. A 2D nLC × µFFE separation of a Chromeo P503 labeled tryptic digest of BSA was performed to demonstrate the high peak capacity possible due to the low surface adsorption in the 3D printed ABS devices, even in the absence of surface coatings or buffer additives.
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Affiliation(s)
- Sarah K. Anciaux
- University of Minnesota, Department of Chemistry, 207 Pleasant St. SE, Minneapolis, MN, 55455
| | - Michael T. Bowser
- University of Minnesota, Department of Chemistry, 207 Pleasant St. SE, Minneapolis, MN, 55455
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4
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Saar KL, Zhang Y, Müller T, Kumar CP, Devenish S, Lynn A, Łapińska U, Yang X, Linse S, Knowles TPJ. On-chip label-free protein analysis with downstream electrodes for direct removal of electrolysis products. LAB ON A CHIP 2017; 18:162-170. [PMID: 29192926 DOI: 10.1039/c7lc00797c] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ability to apply highly controlled electric fields within microfluidic devices is valuable as a basis for preparative and analytical processes. A challenge encountered in the context of such approaches in conductive media, including aqueous buffers, is the generation of electrolysis products at the electrode/liquid interface which can lead to contamination, perturb fluid flows and generally interfere with the measurement process. Here, we address this challenge by designing a single layer microfluidic device architecture where the electric potential is applied outside and downstream of the microfluidic device while the field is propagated back to the chip via the use of a co-flowing highly conductive electrolyte solution that forms a stable interface at the separation region of the device. The co-flowing electrolyte ensures that all the generated electrolysis products, including Joule heat and gaseous products, are flowed away from the chip without coming into contact with the analytes while the single layer fabrication process where all the structures are defined lithographically allows producing the devices in a simple yet highly reproducible manner. We demonstrate that by allowing stable and effective application of electric fields in excess of 100 V cm-1, the described platform provides the basis for rapid separation of heterogeneous mixtures of proteins and protein complexes directly in their native buffers as well as for the simultaneous quantification of their charge states. We illustrate this by probing the interactions in a mixture of an amyloid forming protein, amyloid-β, and a molecular chaperone, Brichos, known to inhibit the process of amyloid formation. The availability of a platform for applying stable electric fields and its compatibility with single-layer soft-lithography processes opens up the possibility of separating and analysing a wide range of molecules on chip, including those with similar electrophoretic mobilities.
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Affiliation(s)
- Kadi L Saar
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
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Novo P, Janasek D. Current advances and challenges in microfluidic free-flow electrophoresis-A critical review. Anal Chim Acta 2017; 991:9-29. [PMID: 29031303 DOI: 10.1016/j.aca.2017.08.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/10/2017] [Accepted: 08/11/2017] [Indexed: 12/30/2022]
Abstract
The research field on microfluidic free-flow electrophoresis has developed vast amounts of devices, methods, applications and raised new questions, often in analogy to conventional techniques from which it derives. Most efforts have been employed on device development and a myriad of architectures and fabrication techniques have been reported using simple proof-of-principle separations. As technological aspects reach a quite mature state, researchers' new challenges include the development of protocols for the separation of complex mixtures, as required in the fields of application. The success of this effort is extremely dependent on the capability to transfer the device's fabrication to an industrial setting as well as to ensure interfacing simplicity, namely at the solutions' supply and collection, and actuation such as electric potential application and temperature control. Other advanced applications such as direct interfacing to downstream systems such as mass spectrometry, integration of sensing and feedback controls will require further development in the laboratory. In this review we provide an overview on the field, from basic concepts, through advanced developments both in the theoretical and experimental arenas, and addressing the above details. A comprehensive survey of designs, materials and applications is presented with particular highlights to most recent developments, namely the integration of electrodes, flow control and hyphenation of microfluidic free-flow electrophoresis with other techniques.
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Affiliation(s)
- Pedro Novo
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., 44227, Otto-Hahn-Str. 6b, Dortmund, Germany
| | - Dirk Janasek
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., 44227, Otto-Hahn-Str. 6b, Dortmund, Germany.
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6
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Kochmann S, Agostino FJ, LeBlanc JCY, Krylov SN. Hyphenation of Production-Scale Free-Flow Electrophoresis to Electrospray Ionization Mass Spectrometry Using a Highly Conductive Background Electrolyte. Anal Chem 2016; 88:8415-20. [PMID: 27462727 DOI: 10.1021/acs.analchem.6b02235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this technical note, we demonstrate the hyphenation of production-scale free-flow electrophoresis (FFE) and sheathless electrospray ionization mass spectrometry (ESI-MS). In contrast to previous hyphenation approaches, we used a highly conductive background electrolyte (BGE) required for production-scale FFE. We found that this kind of BGE as well as a production-scale setup leads to significant electric interference between FFE and MS. This interference prevents steady-state FFE operation. We examine this interference in detail and discuss possible solutions to this issue. We demonstrate that the straightforward grounding of the transfer line removes the influence of ESI-MS on FFE, but creates a current leak from the ESI interface, which adversely affects the ESI spray. Furthermore, we show that only the electrical disconnection of the ESI probe from the FFE-MS transfer line suppresses this undesirable current. In order to facilitate the electrical disconnection we used a low conductivity, silica-based ESI probe with withdrawn inner capillary. This approach allowed the interference-free hyphenation of production-scale FFE (using a highly conductive BGE) with ESI-MS.
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Affiliation(s)
- Sven Kochmann
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
| | - Fletcher J Agostino
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
| | | | - Sergey N Krylov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
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7
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Kong FZ, Yang Y, He YC, Zhang Q, Li GQ, Fan LY, Xiao H, Li S, Cao CX. Design of suitable carrier buffer for free-flow zone electrophoresis by charge-to-mass ratio and band broadening analysis. Electrophoresis 2016; 37:2393-400. [DOI: 10.1002/elps.201600040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/05/2016] [Accepted: 06/14/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Fan-zhi Kong
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Ying Yang
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
- School of Bioscience and Bioengineering; South China University of Technology; Guangzhou P. R. China
| | - Yu-chen He
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Qiang Zhang
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Guo-qing Li
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Liu-yin Fan
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Hua Xiao
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
| | - Shan Li
- School of Bioscience and Bioengineering; South China University of Technology; Guangzhou P. R. China
| | - Cheng-xi Cao
- Laboratory of Analytical Biochemistry and Bio-separation, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai P. R. China
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8
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Abstract
The cost, time, and restrictions on creative flexibility associated with current fabrication methods present significant challenges in the development and application of microfluidic devices. Additive manufacturing, also referred to as three-dimensional (3D) printing, provides many advantages over existing methods. With 3D printing, devices can be made in a cost-effective manner with the ability to rapidly prototype new designs. We have fabricated a micro free-flow electrophoresis (μFFE) device using a low-cost, consumer-grade 3D printer. Test prints were performed to determine the minimum feature sizes that could be reproducibly produced using 3D printing fabrication. Microfluidic ridges could be fabricated with dimensions as small as 20 μm high × 640 μm wide. Minimum valley dimensions were 30 μm wide × 130 μm wide. An acetone vapor bath was used to smooth acrylonitrile-butadiene-styrene (ABS) surfaces and facilitate bonding of fully enclosed channels. The surfaces of the 3D-printed features were profiled and compared to a similar device fabricated in a glass substrate. Stable stream profiles were obtained in a 3D-printed μFFE device. Separations of fluorescent dyes in the 3D-printed device and its glass counterpart were comparable. A μFFE separation of myoglobin and cytochrome c was also demonstrated on a 3D-printed device. Limits of detection for rhodamine 110 were determined to be 2 and 0.3 nM for the 3D-printed and glass devices, respectively.
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Affiliation(s)
- Sarah K Anciaux
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Matthew Geiger
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Michael T Bowser
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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9
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Geiger M, Bowser MT. Effect of Fluorescent Labels on Peptide and Amino Acid Sample Dimensionality in Two Dimensional nLC × μFFE Separations. Anal Chem 2016; 88:2177-87. [DOI: 10.1021/acs.analchem.5b03811] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew Geiger
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - Michael T. Bowser
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
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10
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Geiger M, Harstad RK, Bowser MT. Effect of Surface Adsorption on Temporal and Spatial Broadening in Micro Free Flow Electrophoresis. Anal Chem 2015; 87:11682-90. [DOI: 10.1021/acs.analchem.5b02262] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew Geiger
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - Rachel K. Harstad
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - Michael T. Bowser
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
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11
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Kinde TF, Lopez TD, Dutta D. Electrophoretic extraction of low molecular weight cationic analytes from sodium dodecyl sulfate containing sample matrices for their direct electrospray ionization mass spectrometry. Anal Chem 2015; 87:2702-9. [PMID: 25664891 PMCID: PMC4455540 DOI: 10.1021/ac503903j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
While the use of sodium dodecyl sulfate (SDS) in separation buffers allows efficient analysis of complex mixtures, its presence in the sample matrix is known to severely interfere with the mass-spectrometric characterization of analyte molecules. In this article, we report a microfluidic device that addresses this analytical challenge by enabling inline electrospray ionization mass spectrometry (ESI-MS) of low molecular weight cationic samples prepared in SDS containing matrices. The functionality of this device relies on the continuous extraction of analyte molecules into an SDS-free solvent stream based on the free-flow zone electrophoresis (FFZE) technique prior to their ESI-MS analysis. The reported extraction was accomplished in our current work in a glass channel with microelectrodes fabricated along its sidewalls to realize the desired electric field. Our experiments show that a key challenge to successfully operating such a device is to suppress the electroosmotically driven fluid circulations generated in its extraction channel that otherwise tend to vigorously mix the liquid streams flowing through this duct. A new coating medium, N-(2-triethoxysilylpropyl) formamide, recently demonstrated by our laboratory to nearly eliminate electroosmotic flow in glass microchannels was employed to address this issue. Applying this surface modifier, we were able to efficiently extract two different peptides, human angiotensin I and MRFA, individually from an SDS containing matrix using the FFZE method and detect them at concentrations down to 3.7 and 6.3 μg/mL, respectively, in samples containing as much as 10 mM SDS. Notice that in addition to greatly reducing the amount of SDS entering the MS instrument, the reported approach allows rapid solvent exchange for facilitating efficient analyte ionization desired in ESI-MS analysis.
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Affiliation(s)
- Tristan F. Kinde
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Thomas D. Lopez
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Debashis Dutta
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
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12
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Geiger M, Frost NW, Bowser MT. Comprehensive Multidimensional Separations of Peptides Using Nano-Liquid Chromatography Coupled with Micro Free Flow Electrophoresis. Anal Chem 2014; 86:5136-42. [DOI: 10.1021/ac500939q] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Matthew Geiger
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - Nicholas W. Frost
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - Michael T. Bowser
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
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13
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Dutta D. A method-of-moments formulation for describing hydrodynamic dispersion of analyte streams in free-flow zone electrophoresis. J Chromatogr A 2014; 1340:134-8. [DOI: 10.1016/j.chroma.2014.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 01/08/2023]
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14
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Shao J, Fan LY, Cao CX, Huang XQ, Xu YQ. Quantitative investigation of resolution increase of free-flow electrophoresis via simple interval sample injection and separation. Electrophoresis 2012; 33:2065-74. [DOI: 10.1002/elps.201200169] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jing Shao
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Liu-Yin Fan
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Cheng-Xi Cao
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Xian-Qing Huang
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Yu-Quan Xu
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
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Abstract
Micro free flow electrophoresis (micro-FFE) is a continuous micro-separation or preparation technique, which has been applied in the analysis of biomolecules, such as cells, sub cell organics and proteins. In this review, the recent progresses in micro FFE are summarized, with emphasis on the design of microchips, the separation modes and the applications of micro-FFE. Furthermore, the further developments of micro-FFE are prospected.
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Affiliation(s)
- Pingli Wang
- National Chromatographic R. & A. Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Advances in mass spectrometry-based post-column bioaffinity profiling of mixtures. Anal Bioanal Chem 2010; 399:2655-68. [PMID: 21107824 PMCID: PMC3043236 DOI: 10.1007/s00216-010-4406-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/29/2010] [Accepted: 10/31/2010] [Indexed: 10/29/2022]
Abstract
In the screening of complex mixtures, for example combinatorial libraries, natural extracts, and metabolic incubations, different approaches are used for integrated bioaffinity screening. Four major strategies can be used for screening of bioactive mixtures for protein targets-pre-column and post-column off-line, at-line, and on-line strategies. The focus of this review is on recent developments in post-column on-line screening, and the role of mass spectrometry (MS) in these systems. On-line screening systems integrate separation sciences, mass spectrometry, and biochemical methodology, enabling screening for active compounds in complex mixtures. There are three main variants of on-line MS based bioassays: the mass spectrometer is used for ligand identification only; the mass spectrometer is used for both ligand identification and bioassay readout; or MS detection is conducted in parallel with at-line microfractionation with off-line bioaffinity analysis. On the basis of the different fields of application of on-line screening, the principles are explained and their usefulness in the different fields of drug research is critically evaluated. Furthermore, off-line screening is discussed briefly with the on-line and at-line approaches.
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Wen J, Wilker EW, Yaffe MB, Jensen KF. Microfluidic preparative free-flow isoelectric focusing: system optimization for protein complex separation. Anal Chem 2010; 82:1253-60. [PMID: 20092256 DOI: 10.1021/ac902157e] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Isoelectric focusing (IEF) is the first step for two-dimensional (2D) gel electrophoresis and plays an important role in sample purification for proteomics. However, biases in protein size and pI resolution, as well as limitations in sample volume, gel capacity, sample loss, and experimental time, remain challenges. In order to address some of the limitations of traditional IEF, we present a microfluidic free flow IEF (FF-IEF) device for continuous protein separation into 24 fractions. The device reproducibly establishes a nearly linear pH gradient from 4 to 10. Optimized dynamic coatings of 4% poly(vinyl alcohol) (PVA) minimize peak broadening by transverse electrokinetic flows. Even though the device operates at high electric fields (up to 370 V/cm), efficient cooling maintains solution temperature inside the separation channel controllably in the range 2-25 degrees C. Protein samples with a dynamic concentration range from microg/mL to mg/mL can be loaded into the microdevice at a flow rate of 1 mL/h and residence time of approximately 12 min. By using a protein complex of nine proteins and 13 isoforms, we demonstrate improved separation with the FF-IEF system over traditional 2D gel electrophoresis. Device-to-device reproducibility is also illustrated through the efficient depletion of the albumin and hemoglobin assays. Post-device sample concentrations result in a 10-20-fold increase, which allow for isolation and detection of low abundance proteins. The separation of specific proteins from a whole cell lysate is demonstrated as an example. The microdevice has the further benefits of retaining high molecular weight proteins, providing higher yield of protein that has a broader range in pI, and reducing experimental time compared to conventional IEF IGP gel strip approaches.
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Affiliation(s)
- Jian Wen
- Department of Chemical Engineering, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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Kasicka V. From micro to macro: conversion of capillary electrophoretic separations of biomolecules and bioparticles to preparative free-flow electrophoresis scale. Electrophoresis 2009; 30 Suppl 1:S40-52. [PMID: 19517515 DOI: 10.1002/elps.200900156] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This invited contribution in the special issue of Electrophoresis published in celebration of the 30th Anniversary of this journal reflects the impact of our milestone paper [Prusík, Z., Kasicka, V., Mudra, P., Stepánek, J., Smékal, O., Hlavácek, J., Electrophoresis 1990, 11, 932-936] in the area of conversion of microscale analytical and micropreparative CE separations of biomolecules and bioparticles into (macro)preparative free-flow electrophoresis (FFE) scale on the basis of a correlation between CE and FFE methods. In addition to the survey of advances in the relatively narrow field of CE-FFE correlation and CE-FFE conversion, a comprehensive review of the recent developments of micropreparative CE and (macro)preparative FFE techniques is also presented and applications of these techniques to micro- and (macro)preparative separations and purifications of biomolecules and bioparticles are demonstrated. The review covers the period since the year of publication of the above paper, i.e. ca. the last 20 years.
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Affiliation(s)
- Václav Kasicka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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20
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Micro free-flow electrophoresis: theory and applications. Anal Bioanal Chem 2009; 394:187-98. [PMID: 19290514 DOI: 10.1007/s00216-009-2656-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 01/23/2009] [Accepted: 01/26/2009] [Indexed: 10/21/2022]
Abstract
Free-flow electrophoresis (FFE) is a technique that performs an electrophoretic separation on a continuous stream of analyte as it flows through a planar flow channel. The electric field is applied perpendicularly to the flow to deflect analytes laterally according to their mobility as they flow through the separation channel. Miniaturization of FFE (microFFE) over the past 15 years has allowed analytical and preparative separation of small volume samples. Advances in chip design have improved separations by reducing interference from bubbles generated by electrolysis. Mechanisms of band broadening have been examined theoretically and experimentally to improve resolution in microFFE. Separations using various modes such as zone electrophoresis, isoelectric focusing, isotachophoresis, and field-step electrophoresis have been demonstrated.
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Ho S, Critchley K, Lilly GD, Shim B, Kotov NA. Free flow electrophoresis for the separation of CdTe nanoparticles. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b820703h] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Kohlheyer D, Eijkel JCT, van den Berg A, Schasfoort RBM. Miniaturizing free-flow electrophoresis – a critical review. Electrophoresis 2008; 29:977-93. [DOI: 10.1002/elps.200700725] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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23
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Abstract
Biochemical sample mixtures are commonly separated in batch processes, such as filtration, centrifugation, chromatography or electrophoresis. In recent years, however, many research groups have demonstrated continuous flow separation methods in microfluidic devices. Such separation methods are characterised by continuous injection, real-time monitoring, as well as continuous collection, which makes them ideal for combination with upstream and downstream applications. Importantly, in continuous flow separation the sample components are deflected from the main direction of flow, either by means of a force field (electric, magnetic, acoustic, optical etc.), or by intelligent positioning of obstacles in combination with laminar flow profiles. Sample components susceptible to deflection can be spatially separated. A large variety of methods has been reported, some of these are miniaturised versions of larger scale methods, others are only possible in microfluidic regimes. Researchers now have a diverse toolbox to choose from and it is likely that continuous flow methods will play an important role in future point-of-care or in-the-field analysis devices.
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Affiliation(s)
- Nicole Pamme
- The University of Hull, Department of Chemistry, Cottingham Road, Hull, UK HU6 7RX.
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24
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Peterson RR, Cliffel DE. Continuous free-flow electrophoresis of water-soluble monolayer-protected clusters. Anal Chem 2007; 77:4348-53. [PMID: 16013845 DOI: 10.1021/ac0502495] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There has recently been a surge of interest in the properties and applications of monolayer protected clusters (MPCs). MPCs are metal nanoparticles that have unique optical, chemical, and electrochemical properties resulting from their small size. Because the size defines their properties, MPC particle size fractionation is important for control of the MPC characteristics for use in many potential applications. This paper explores the use of continuous free-flow electrophoresis (CFE) for the size fractionation of N-(2-mercaptopropionyl)glycine (tiopronin) monolayer protected gold clusters into monodisperse nanoparticle samples. CFE is a fractionation technique that isolates monodisperse particle sizes into several different collection vials on the tens of milligrams scale. This allows the MPCs to be separated based on their electrophoretic mobilities into isolated, monodisperse particles across a wide range of sizes. CFE separation of water-soluble tiopronin MPCs yielded fractions that varied in color, UV-visible spectra, transmission electron microscopy (TEM) size histograms, and solubility, indicating narrow size dispersity in the isolated fractions. UV-visible spectrophotometry verified the separation of the tiopronin MPCs through the inspection of surface plasmon resonance peak sizes for the different fractions. TEM was also used to verify the narrowed dispersity of MPC samples. The ability to separate water-soluble nanoparticles into 30 or more fractions in a continuous flow process will enable future studies on their size dependent properties.
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Affiliation(s)
- Rachel R Peterson
- Department of Chemistry, Vanderbilt University, VU Station B 351822, Nashville, Tennessee 37235-1882, USA
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25
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Janasek D, Schilling M, Franzke J, Manz A. Isotachophoresis in free-flow using a miniaturized device. Anal Chem 2007; 78:3815-9. [PMID: 16737242 DOI: 10.1021/ac060063l] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For the first time, we report a miniaturized approach for isotachophoresis employing the technique of free-flow electrophoresis. Using a micromachined separation chamber with a volume of 200 nL, a sample mixture of fluorescein, eosin G, and acetylsalicylic acid was separated, stacked, and concentrated in less than a minute. Additionally, an isotachophoretic separation of a reaction mixture of myoglobin and fluoresceinisothiocyanate as a fluorescence label has shown the potential of this method for on-line sample preparation.
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Affiliation(s)
- Dirk Janasek
- Institute for Analytical Sciences Dortmund and Berlin, Bunsen-Kirchhoff-Strasse 11, D-44139 Dortmund, Germany.
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26
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Stone VN, Baldock SJ, Croasdell LA, Dillon LA, Fielden PR, Goddard NJ, Thomas CLP, Treves Brown BJ. Free flow isotachophoresis in an injection moulded miniaturised separation chamber with integrated electrodes. J Chromatogr A 2006; 1155:199-205. [PMID: 17229431 DOI: 10.1016/j.chroma.2006.12.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 11/28/2006] [Accepted: 12/01/2006] [Indexed: 11/24/2022]
Abstract
An injection moulded free flow isotachophoresis (FFITP) microdevice with integrated carbon fibre loaded electrodes with a separation chamber of 36.4mm wide, 28.7 mm long and 100 microm deep is presented. The microdevice was completely fabricated by injection moulding in carbon fibre loaded polystyrene for the electrodes and crystal polystyrene for the remainder of the chip and was bonded together using ultrasonic welding. Two injection moulded electrode designs were compared, one with the electrode surface level with the separation chamber and one with a recessed electrode. Separations of two anionic dyes, 0.2mM each of amaranth and acid green and separations of 0.2mM each of amaranth, bromophenol blue and glutamate were performed on the microdevice. Flow rates of 1.25 ml min(-1) for the leading and terminating electrolytes were used and a flow rate of 0.63 ml min(-1) for the sample. Electric fields of up to 370 V cm(-1) were applied across the separation chamber. Joule heating was not found to be significant although out-gassing was observed at drive currents greater than 3 mA.
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Affiliation(s)
- Victoria N Stone
- School of Chemical Engineering and Analytical Science, The University of Manchester, PO Box 88, Manchester M60 1QD, UK
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27
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Pereira de Jesus D, Blanes L, do Lago CL. Microchip free-flow electrophoresis on glass substrate using laser-printing toner as structural material. Electrophoresis 2006; 27:4935-42. [PMID: 17161008 DOI: 10.1002/elps.200600137] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work, a microfluidic free-flow electrophoresis device, obtained by thermal toner transferring on glass substrate, is presented. A microdevice can be manufactured in only 1 h. The layout of the microdevice was designed in order to improve the fluidic and electrical characteristics. The separation channel is 8 microm deep and presents an internal volume of 1.42 microL. The deleterious electrolysis effects were overcome by using a system that isolates the electrolysis products from the separation channel. The Joule heating dissipation in the separation channel was found to be very efficient up to a current density of 8.83 mA/mm(2) that corresponds to a power dissipation per unit volume of running electrolyte of 172 mW/microL. Promising results were obtained in the evaluation of the microdevices for the separation of ionic dyes. The microfluidic device can be used for a continuous sample pretreatment step for micro total analysis system.
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Affiliation(s)
- Dosil Pereira de Jesus
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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28
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Abstract
Micrometre-scale analytical devices are more attractive than their macroscale counterparts for various reasons. For example, they use smaller volumes of reagents and are therefore cheaper, quicker and less hazardous to use, and more environmentally appealing. Scaling laws compare the relative performance of a system as the dimensions of the system change, and can predict the operational success of miniaturized chemical separation, reaction and detection devices before they are fabricated. Some devices designed using basic principles of scaling are now commercially available, and opportunities for miniaturizing new and challenging analytical systems continue to arise.
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Affiliation(s)
- Dirk Janasek
- ISAS-Institute for Analytical Sciences, Bunsen-Kirchhoff-Str. 11, D-44139 Dortmund, Germany.
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29
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10 Free-flow isoelectric focusing. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0149-6395(05)80013-3] [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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30
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Schenk T, Molendijk A, Irth H, Tjaden UR, van der Greef J. Liquid chromatography coupled on-line to flow cytometry for postcolumn homogeneous biochemical detection. Anal Chem 2004; 75:4272-8. [PMID: 14632146 DOI: 10.1021/ac0341822] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The feasibility of flow cytometry as read-out principle for homogeneous cell- or bead-based assays coupled on-line to LC is demonstrated using digoxin-coated beads (Dig-Beads) and fluorescent-labeled anti-digoxin (AD-FITC) as model system. The assay is carried out in a postcolumn continuous-flow reaction detection system where the AD-FITC and Dig-Beads are simultaneously added to the eluate of an LC separation column. Binding of AD-FITC to Dig-Beads results in a constant amount of fluorescence associated with the beads, which is detected by the flow cytometer. The presence of active compounds, such as digoxin and its analogues, in the sample will results in a decrease of the AD-FITC-Dig-Bead complex and, consequently, in the bead-associated fluorescence. Hence, the bead-associated fluorescence detected is inversely related to the digoxin concentration. A data-handling algorithm was developed in-house for adequate analysis of raw data output from the flow cytometer. Various conditions that influence the performance of this novel LC-biochemical detection (LC-BCD) system were investigated to determine the optimal settings of the bead-based biochemical interaction. The optimized flow injection bead-based assay was capable of detecting very low concentrations of digoxigenin (0.5 nmol/L), digoxin (0.1 nmol/L), and gitoxigenin (50 nmol/L). The applicability of LC coupled on-line to flow cytometry was demonstrated by the individual detection of digoxin, digoxigenin, and gitoxigenin in a single LC analysis. The successful coupling of LC on-line to flow cytometry principally enables the use of a wide range of new homogeneous assay formats in LC-BCD, such as membrane-bound receptor assays, cell-binding assays, and functional cell-based assays. Next to the ability to use insoluble targets, and also multiplexing assays, i.e., performing a number of assays simultaneously, using color- or size-coded beads becomes at hand in LC-BCD.
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Affiliation(s)
- T Schenk
- Kiadis B. V., Niels Bohrweg 11-13, 2333 CA, Leiden, The Netherlands.
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31
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Abstract
A microfluidic device has been developed for continuous separation in free-flow electrophoresis (FFE) mode. A mixture of two fluorescent reagents is separated into two component streams in 75 ms using a sample flow rate of 2 nL/s. The residence time of sample in the whole separation compartment is 2 s. The separation bed volume is 0.2 microL. The chip has also been used for free-flow electrophoresis of fluorescein-5-isothiocyanate-labeled amino acids in both aqueous and binary media. The short residence time and small sample flow rate make the FFE chip feasible for on-line monitoring on production lines and other chemical or biochemical processes. The in-house-made chip was composed of a plain glass substrate of 1.5-mm thickness and a PDMS layer of 0.3-mm thickness with micromachined channels. The channel design presented in this paper is versatile. With the same kind of PDMS substrates, chips for various purposes can be made depending on the locations of the reservoirs, which are cut out on the PDMS substrate. The results presented verify the scaling laws and allow prediction of FFE performances comparable to what is now state of the art on capillary electrophoresis chips.
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Affiliation(s)
- Chao-Xuan Zhang
- Chemistry Department, Imperial College London, London SW7 2AY U.K
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32
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Huikko K, Kostiainen R, Kotiaho T. Introduction to micro-analytical systems: bioanalytical and pharmaceutical applications. Eur J Pharm Sci 2003; 20:149-71. [PMID: 14550882 DOI: 10.1016/s0928-0987(03)00147-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This review presents a brief overview of recent developments in miniaturization of analytical instruments utilizing microfabrication technology. The concept 'Micro-Total Analysis Systems micro-TAS)', also termed 'Lab-on-a-chip', and the latest progresses in the development of microfabricated separation devices and on-chip detection techniques are discussed. Applications of micro-analytical methods to bioanalytical and pharmaceutical studies are also described, including chemical reactions, assays, and analytical separations of biomolecules in micro-scale.
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Affiliation(s)
- Katri Huikko
- Department of Pharmacy, PO Box 56, FIN-00014 University of Helsinki, Helsinki, Finland.
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Junkers J, Schmitt-Kopplin P, Munch JC, Kettrup A. Up-scaling capillary zone electrophoresis separations of polydisperse anionic polyelectrolytes with preparative free-flow electrophoresis exemplified with a soil fulvic acid. Electrophoresis 2002; 23:2872-9. [PMID: 12207294 DOI: 10.1002/1522-2683(200209)23:17<2872::aid-elps2872>3.0.co;2-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A scale-up of analytical capillary zone electrophoresis (CZE) to preparative free-flow electrophoresis (FFE) is described. FFE allows fractionations based on charge densities in larger amounts than in CZE, enabling further off-line analysis of the fractions. Model compounds (carboxylic acids and polystyrene sulfonates) showed a similar behavior in FFE as in CZE. Diffusion and electrodynamic distortion effects are more pronounced in FFE than in CZE. A soil fulvic acid was analyzed by CZE and fractionated by FFE. A comparison of the FFE fractions with CZE measurements of the same sample using the effective mobility scale showed good agreement of the two methods.
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Affiliation(s)
- Jens Junkers
- Institute for Soil Ecology, Forschungszentrum für Umwelt und Gesundheit, Neuherberg, Germany
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