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Zhang Y, Fu X, Ping G. Selective Enrichment of Low-abundance Compounds in a Mixture by Capillary Electrophoresis. J Chromatogr A 2020; 1635:461737. [PMID: 33253999 DOI: 10.1016/j.chroma.2020.461737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 10/23/2022]
Abstract
Recently, we developed a new approach for the selective enrichment of low-abundance compounds in biological samples by capillary electrophoresis. As a model test, the low-abundance compound lysozyme was successfully fractionated from a mixture containing high-abundance compound BSA (1:4500) using a custom-made apparatus. The feasibility of this approach for real complex biological samples was verified by rat serum, wherein three low-abundance proteins with high charge/mass ratios were detected.
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Affiliation(s)
- Yong Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China.
| | - Xia Fu
- Linyi Inspection and Testing Center, 276000, China
| | - Guichen Ping
- College of Science, Inner Mongolia Agricultural University, Hohhot China.
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2
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Profiling of N-linked glycans from 100 cells by capillary electrophoresis with large-volume dual preconcentration by isotachophoresis and stacking. J Chromatogr A 2018; 1565:138-144. [DOI: 10.1016/j.chroma.2018.06.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/06/2018] [Accepted: 06/14/2018] [Indexed: 01/19/2023]
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3
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Hendrickx S, de Malsche W, Cabooter D. An overview of the use of microchips in electrophoretic separation techniques: fabrication, separation modes, sample preparation opportunities, and on-chip detection. Methods Mol Biol 2015; 1274:3-17. [PMID: 25673478 DOI: 10.1007/978-1-4939-2353-3_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This chapter is intended as a basic introduction to microchip-based capillary electrophoresis to set the scene for newcomers and give pointers to reference material. An outline of some commonly used setups and key concepts is given, many of which are explored in greater depth in later chapters.
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Affiliation(s)
- Stijn Hendrickx
- Department of Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, KU Leuven, O&N2 923, Herestraat 49, 3000, Leuven, Belgium
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Li X, Li Y, Zhao L, Shen J, Zhang Y, Bao JJ. Velocity gap mode of capillary electrophoresis developed for high-resolution chiral separations. Electrophoresis 2014; 35:2778-84. [DOI: 10.1002/elps.201400081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Xue Li
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Youxin Li
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Lumeng Zhao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Jianguo Shen
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Yong Zhang
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - James J. Bao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
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5
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Azadi G, Tripathi A. Surfactant-induced electroosmotic flow in microfluidic capillaries. Electrophoresis 2012; 33:2094-101. [DOI: 10.1002/elps.201100633] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Giordano BC, Burgi DS, Hart SJ, Terray A. On-line sample pre-concentration in microfluidic devices: a review. Anal Chim Acta 2012; 718:11-24. [PMID: 22305893 DOI: 10.1016/j.aca.2011.12.050] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/01/2011] [Accepted: 12/21/2011] [Indexed: 11/25/2022]
Abstract
On-line sample preconcentration is an essential tool in the development of microfluidic-based separation platforms. In order to become more competitive with traditional separation techniques, the community must continue to develop newer and more novel methods to improve detection limits, remove unwanted sample matrix components that disrupt separation performance, and enrich/purify analytes for other chip-based actions. Our goal in this review is to familiarize the reader with many of the options available for on-chip concentration enhancement with a focus on those manuscripts that, in our assessment, best describe the fundamental principles that govern those enhancements. Sections discussing both electrophoretic and nonelectrophoretic modes of preconcentration are included with a focus on device design and mechanisms of preconcentration. This review is not meant to be a comprehensive collection of every available example, but our hope is that by learning how on-line sample concentration techniques are being applied today, the reader will be inspired to apply these techniques to further enhance their own programs.
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Affiliation(s)
- Braden C Giordano
- Naval Research Laboratory, Chemistry Division, Washington, DC 20375-5342, United States.
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AL-Othman ZA, Ali I. NANO CAPILLARY ELECTROPHORESIS IN MICROCHIPS: A NEED OF THE PRESENT CENTURY. J LIQ CHROMATOGR R T 2011. [DOI: 10.1080/10826076.2011.566031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Zeid A. AL-Othman
- a Department of Chemistry, College of Science , King Saud University , Riyadh, Kingdom of Saudi Arabia
| | - Imran Ali
- b Department of Chemistry , Jamia Millia Islamia, (Central University) , New Delhi, India
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8
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Currie CA, Shim JS, Lee SH, Ahn C, Limbach PA, Halsall HB, Heineman WR. Comparing polyelectrolyte multilayer-coated PMMA microfluidic devices and glass microchips for electrophoretic separations. Electrophoresis 2010; 30:4245-50. [PMID: 20013912 DOI: 10.1002/elps.200900403] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There is a continuing drive in microfluidics to transfer microchip systems from the more expensive glass microchips to cheaper polymer microchips. Here, we investigate using polyelectrolyte multilayers (PEM) as a coating system for PMMA microchips to improve their functionality. The multilayer system was prepared by layer-to-layer deposition of poly(diallyldimethylammonium) chloride and polystyrene sulfonate. Practical aspects of coating PMMA microchips were explored. The multilayer buildup process was monitored using EOF measurements, and the stability of the PEM was investigated. The performance of the PEM-PMMA microchip was compared with those of a standard glass microchip and a PEM-glass microchip in terms of EOF and separating two fluorescent dyes. Several key findings in the development of the multilayer coating procedure for PMMA chips are also presented. It was found that, with careful preparation, a PEM-PMMA microchip can be prepared that has properties comparable--and in some cases superior--to those of a standard glass microchip.
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Affiliation(s)
- Christa A Currie
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
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Guan Q, Henry CS. Improving MCE with electrochemical detection using a bubble cell and sample stacking techniques. Electrophoresis 2009; 30:3339-46. [PMID: 19802848 PMCID: PMC3005344 DOI: 10.1002/elps.200900316] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Two efforts to improve the sensitivity and limits of detection for MCE with electrochemical detection are presented here. One is the implementation of a capillary expansion (bubble cell) at the detection zone to increase the exposed working electrode surface area. Bubble cell widths were varied from 1x to 10x the separation channel width (50 mum) to investigate the effects of electrode surface area on detection sensitivity, LOD, and separation efficiency. Improved detection sensitivity and decreased detection limits were obtained with increased bubble cell width, and LODs of dopamine and catechol detected in a 5x bubble cell were 25 and 50 nM, respectively. Meanwhile, fluorescent imaging results demonstrated approximately 8 and approximately 12% loss in separation efficiency in 4x and 5x bubble cell, respectively. Another effort at reducing the LOD involves using field amplified sample injection for gated injection and field amplified sample stacking for hydrodynamic injection. Stacking effects are shown for both methods using amperometric detection and pulsed amperometric detection. The LODs of dopamine in a 4x bubble cell were 8 and 20 nM using field amplified sample injection and field amplified sample stacking, respectively. However, improved LODs were not obtained for anionic analytes using either stacking technique.
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Affiliation(s)
- Qian Guan
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
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Hitchcock AM, Bowman MJ, Staples GO, Zaia J. Improved workup for glycosaminoglycan disaccharide analysis using CE with LIF detection. Electrophoresis 2009; 29:4538-48. [PMID: 19035406 DOI: 10.1002/elps.200800335] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This work describes improved workup and instrumental conditions to enable robust, sensitive glycosaminoglycan (GAG) disaccharide analysis from complex biological samples. In the process of applying CE with LIF to GAG disaccharide analysis in biological samples, we have made improvements to existing methods. These include (i) optimization of reductive amination conditions, (ii) improvement in sensitivity through the use of a cellulose cleanup procedure for the derivatization, and (iii) optimization of separation conditions for robustness and reproducibility. The improved method enables analysis of disaccharide quantities as low as 1 pmol prior to derivatization. Biological GAG samples were exhaustively digested using lyase enzymes, the disaccharide products and standards were derivatized with the fluorophore 2-aminoacridone and subjected to reversed polarity CE-LIF detection. These conditions resolved all known chondroitin sulfate (CS) disaccharides or 11 of 12 standard heparin/heparan sulfate disaccharides, using 50 mM phosphate buffer, pH 3.5, and reversed polarity at 30 kV with 0.3 psi pressure. Relative standard deviation in migration times of CS ranged from 0.1 to 2.0% over 60 days, and the relative standard deviations of peak areas were less than 3.2%, suggesting that the method is reproducible and precise. The CS disaccharide compositions are similar to those obtained by our group using tandem MS. The reversed polarity CE-LIF disaccharide analysis protocol yields baseline resolution and quantification of heparin/heparan sulfate and CS/dermatan sulfate disaccharides from both standard preparations and biologically relevant proteoglycan samples. The improved CE-LIF method enables disaccharide quantification of biologically relevant proteoglycans from small samples of intact tissue.
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Affiliation(s)
- Alicia M Hitchcock
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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11
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Zhang Y, Wang J, Okamoto Y, Tokeshi M, Kaji N, Baba Y. Velocity Gap Theory Developed for Magnifying Resolutions without Changing Separation Mechanisms or Separation Lengths. Anal Chem 2009; 81:2745-50. [DOI: 10.1021/ac802671m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Yong Zhang
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Jun Wang
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Yukihiro Okamoto
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Manabu Tokeshi
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Noritada Kaji
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Yoshinobu Baba
- Department of Applied Chemistry, Graduate School of Engineering, MEXT Innovative Research Center for Preventive Medical Engineering, Health Technology Research Center, Plasma Nanotechnology Research Center, Nagoya University, Nagoya 464-8603, Japan, National Institute of Advanced Industrial Science and Technology (AIST) Hayashi-cho 2217-14, Takamatsu 761-0395, Japan, and Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
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12
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Sueyoshi K, Kitagawa F, Otsuka K. Recent progress of online sample preconcentration techniques in microchip electrophoresis. J Sep Sci 2008; 31:2650-66. [PMID: 18693308 DOI: 10.1002/jssc.200800272] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Microchip electrophoresis (MCE) has been advanced remarkably by the applications of several separation modes and the integration with several chemical operations on a single planer substrate. MCE shows superior analytical performance, e.g., high-speed analysis, high resolution, low consumption of reagents, and so on, whereas low-concentration sensitivity is still one of the major problems. To overcome this drawback, various online sample preconcentration techniques have been developed in MCE over the past 15 years, which have successfully enhanced the detection sensitivity in MCE. This review highlights recent developments in online sample preconcentration in MCE categorized on the basis of "dynamic" and "static" methods. The dynamic techniques including field amplified stacking, ITP, sweeping, and focusing have been easily applied to MCE, which provide effective enrichments of various analytes. The static techniques such as SPE and filtration have also been combined with MCE. In the static techniques, extremely high preconcentration efficiency can be obtained, compared to the dynamic methods. This review provides comprehensive tables listing the applications and sensitivity enhancement factors of these preconcentration techniques employed in MCE.
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Affiliation(s)
- Kenji Sueyoshi
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
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13
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Chen Y, Zhang L, Chen G. Fabrication, modification, and application of poly(methyl methacrylate) microfluidic chips. Electrophoresis 2008; 29:1801-14. [DOI: 10.1002/elps.200700552] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Zhang Y, Ping G, Kaji N, Tokeshi M, Baba Y. Dynamic modification of poly(methyl methacrylate) chips using poly(vinyl alcohol) for glycosaminoglycan disaccharide isomer separation. Electrophoresis 2007; 28:3308-14. [PMID: 17722188 DOI: 10.1002/elps.200700088] [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] [Indexed: 11/10/2022]
Abstract
We describe a microchip electrophoresis (MCE) method for the assay of unsaturated disaccharides of chondroitin sulfates, dermatan sulfates, and hyaluronic acid (HA). Poly(vinyl alcohol) (PVA) could be irreversibly adsorbed onto poly(methyl methacrylate) (PMMA) substrates and this approach was applicable for dynamic coating. The characteristics of the PMMA surface with PVA coating were evaluated in terms of the wettability, EOF, and adsorption of 2-aminoacridone (AMAC)-labeled disaccharide. The water contact angle decreased from 73 degrees on a pristine PMMA surface to 37.5 degrees on a PVA-coated surface, indicating that the PVA coating increased hydrophilicity. EOF was reduced approximately twofold and was relatively stable. Scanning electron microscopy and fluorescence microscopy images showed that adsorption of AMAC-labeled disaccharides was dramatically suppressed. Using the PVA coating, baseline separation of two pairs of glycosaminoglycan (GAG) disaccharide isomers, DeltaDi-diS(B)/DeltaDi-diS(D) and DeltaDi-0S/DeltaDi-HA, was achieved in Tris-borate buffer within 130 s by MCE.
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Affiliation(s)
- Yong Zhang
- Graduate School of Pharmaceutical Sciences, University of Tokushima, Tokushima, Japan.
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