1
|
Liu X, Zhu H, Sabó J, Lánský Z, Neužil P. Improvement of the signal to noise ratio for fluorescent imaging in microfluidic chips. Sci Rep 2022; 12:18911. [PMID: 36344576 PMCID: PMC9640556 DOI: 10.1038/s41598-022-23426-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022] Open
Abstract
Microfluidics systems can be fabricated in various ways using original silicon glass systems, with easy Si processing and surface modifications for subsequent applications such as cell seeding and their study. Fluorescent imaging of cells became a standard technique for the investigation of cell behavior. Unfortunately, high sensitivity fluorescent imaging, e.g., using total internal reflection fluorescence (TIRF) microscopy, is problematic in these microfluidic systems because the uneven surfaces of the silicon channels' bottoms affect light penetration through the optical filters. In this work, we study the nature of the phenomenon, finding that the problem can be rectified by using a silicon-on-insulator (SOI) substrate, defining the channel depth by the thickness of the top Si layer, and halting the etching at the buried SiO2 layer. Then the fluorescent background signal drops by = 5 times, corresponding to the limit of detection drop from = 0.05 mM to = 50 nM of fluorescein. We demonstrate the importance of a flat surface using TIRF-based single-molecule detection, improving the signal to a noise ratio more than 18 times compared to a conventional Si wafer. Overall, using very high-quality SOI substrates pays off, as it improves the fluorescence image quality due to the increase in signal-to-noise ratio. Concerning the cost of microfluidic device fabrication-design, mask fabrication, wafer processing, and device testing-the initial SOI wafer cost is marginal, and using it improves the system performance.
Collapse
Affiliation(s)
- Xiaocheng Liu
- grid.440588.50000 0001 0307 1240Department of Microsystems Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Hanliang Zhu
- grid.440588.50000 0001 0307 1240Department of Microsystems Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Ján Sabó
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Science, Průmyslová 595, 252 50 Vestec, Czech Republic ,grid.4491.80000 0004 1937 116XDepartment of Physical Chemistry, Faculty of Science, Charles University, Hlavova 8, 12800 Prague 2, Czech Republic
| | - Zdeněk Lánský
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Science, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Pavel Neužil
- grid.440588.50000 0001 0307 1240Department of Microsystems Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an, 710072 Shaanxi People’s Republic of China
| |
Collapse
|
2
|
Piestansky J, Cizmarova I, Matuskova M, Mikus P. Comparison of 1D a 2D ITP-MS performance parameters and application possibilities: Ultratrace determination of B vitamins in human urine. Electrophoresis 2021; 43:998-1009. [PMID: 34597419 DOI: 10.1002/elps.202100209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/06/2021] [Accepted: 09/25/2021] [Indexed: 12/21/2022]
Abstract
The possibility to investigate analytes at ultra-low concentration levels still remains a hot topic in bioanalysis. In this area, various preconcentration techniques are an integral part of analytical procedures. When applying electromigration separation techniques, an isotachophoresis has been advantageously employed many times for this purpose. To solve current biomedical tasks effectively, an advanced two-dimensional isotachophoretic instrument (in a hydrodynamically closed separation system with an enhanced sample load capacity) hyphenated with mass spectrometry (ITP-ITP-MS) has been proposed by Foret and coworkers. As a continuation, this work represents the first study dealing with a full validation of an ITP-ITP-MS method. In order to see the benefits of an online ITP sample pretreatment (preconcentration and clean-up) on the performance parameters, the developed 2D ITP-MS method was compared with a corresponding 1D ITP-MS method. Application potentialities of the compared methods were demonstrated via a determination of two B vitamins, namely thiamine and pyridoxine, in human urine samples. The developed 2D ITP-MS method showed its enhanced effectivity and usefulness for a routine biomedical use (here, a reliable screening of trace B vitamins in human urine without an offline sample preparation).
Collapse
Affiliation(s)
- Juraj Piestansky
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.,Toxicological and Antidoping Center, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic
| | - Ivana Cizmarova
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic
| | - Michaela Matuskova
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic
| | - Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.,Toxicological and Antidoping Center, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic
| |
Collapse
|
3
|
Jender M, Höving S, Novo P, Freier E, Janasek D. Coupling Miniaturized Free-Flow Electrophoresis to Mass Spectrometry via a Multi-Emitter ESI Interface. Anal Chem 2021; 93:7204-7209. [PMID: 33939916 DOI: 10.1021/acs.analchem.1c00200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a novel multi-emitter electrospray ionization (ESI) interface for the coupling of microfluidic free-flow electrophoresis (μFFE) with mass spectrometry (MS). The effluents of the μFFE outlets are analyzed in near real-time, allowing a direct optimization of the electrophoretic separation and an online monitoring of qualitative sample compositions. The short measurement time of just a few seconds for all outlets even enables a reasonable time-dependent monitoring. As a proof of concept, we employ the multi-emitter ESI interface for the continuous identification of analytes at 15 μFFE outlets via MS to optimize the μFFE separation of important players of cellular respiration in operando. The results indicate great potential of the presented system in downstream processing control, for example, for the monitoring and purification of products in continuous-flow microreactors.
Collapse
Affiliation(s)
- Matthias Jender
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
| | - Stefan Höving
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
| | - Pedro Novo
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
| | - Erik Freier
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
| | - Dirk Janasek
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
| |
Collapse
|
4
|
Porter GCE, Sikora SNF, Shim JU, Murray BJ, Tarn MD. On-chip density-based sorting of supercooled droplets and frozen droplets in continuous flow. LAB ON A CHIP 2020; 20:3876-3887. [PMID: 32966480 DOI: 10.1039/d0lc00690d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The freezing of supercooled water to ice and the materials which catalyse this process are of fundamental interest to a wide range of fields. At present, our ability to control, predict or monitor ice formation processes is poor. The isolation and characterisation of frozen droplets from supercooled liquid droplets would provide a means of improving our understanding and control of these processes. Here, we have developed a microfluidic platform for the continuous flow separation of frozen from unfrozen picolitre droplets based on differences in their density, thus allowing the sorting of ice crystals and supercooled water droplets into different outlet channels with 94 ± 2% efficiency. This will, in future, facilitate downstream or off-chip processing of the frozen and unfrozen populations, which could include the analysis and characterisation of ice-active materials or the selection of droplets with a particular ice-nucleating activity.
Collapse
Affiliation(s)
- Grace C E Porter
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK. and School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | | | - Jung-Uk Shim
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Benjamin J Murray
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK.
| | - Mark D Tarn
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK. and School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| |
Collapse
|
5
|
Courtney M, Thompson E, Glawdel T, Ren CL. Counterflow Gradient Focusing in Free-Flow Electrophoresis for Protein Fractionation. Anal Chem 2020; 92:7317-7324. [PMID: 32336087 DOI: 10.1021/acs.analchem.0c01024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Matthew Courtney
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Ethan Thompson
- Department of Nanotechnology Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Tomasz Glawdel
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Carolyn L. Ren
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| |
Collapse
|
6
|
Jender M, Novo P, Maehler D, Münchberg U, Janasek D, Freier E. Multiplexed Online Monitoring of Microfluidic Free-Flow Electrophoresis via Mass Spectrometry. Anal Chem 2020; 92:6764-6769. [PMID: 32289220 DOI: 10.1021/acs.analchem.0c00996] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Free-flow electrophoresis is a tool for the continuous fractionation of electrically charged analytes. In this study, we introduce a novel method to couple microchip-based free-flow electrophoresis with mass spectrometry. The successive connection of multiple microchip outlets to the electrospray ionization source of a mass spectrometer is automated using a multiposition valve. With this novel setup, it is possible to continuously fractionate and collect compounds while simultaneously monitoring the process online with mass spectrometry. The functionality of the method is demonstrated by the successful separation and identification of the biomolecules AMP, ATP, and CoA, which are fundamental for numerous biochemical processes in every organism.
Collapse
Affiliation(s)
- Matthias Jender
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Pedro Novo
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Dominic Maehler
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Ute Münchberg
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Dirk Janasek
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Erik Freier
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| |
Collapse
|
7
|
Lu N, Sticker D, Kretschmann A, Petersen NJ, Kutter JP. A thiol-ene microfluidic device enabling continuous enzymatic digestion and electrophoretic separation as front-end to mass spectrometric peptide analysis. Anal Bioanal Chem 2020; 412:3559-3571. [DOI: 10.1007/s00216-020-02609-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/07/2023]
|
8
|
Arter WE, Levin A, Krainer G, Knowles TPJ. Microfluidic approaches for the analysis of protein-protein interactions in solution. Biophys Rev 2020; 12:575-585. [PMID: 32266673 PMCID: PMC7242286 DOI: 10.1007/s12551-020-00679-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022] Open
Abstract
Exploration and characterisation of the human proteome is a key objective enabling a heightened understanding of biological function, malfunction and pharmaceutical design. Since proteins typically exhibit their behaviour by binding to other proteins, the challenge of probing protein-protein interactions has been the focus of new and improved experimental approaches. Here, we review recently developed microfluidic techniques for the study and quantification of protein-protein interactions. We focus on methodologies that utilise the inherent strength of microfluidics for the control of mass transport on the micron scale, to facilitate surface and membrane-free interrogation and quantification of interacting proteins. Thus, the microfluidic tools described here provide the capability to yield insights on protein-protein interactions under physiological conditions. We first discuss the defining principles of microfluidics, and methods for the analysis of protein-protein interactions that utilise the diffusion-controlled mixing characteristic of fluids at the microscale. We then describe techniques that employ electrophoretic forces to manipulate and fractionate interacting protein systems for their biophysical characterisation, before discussing strategies that use microdroplet compartmentalisation for the analysis of protein interactions. We conclude by highlighting future directions for the field, such as the integration of microfluidic experiments into high-throughput workflows for the investigation of protein interaction networks.
Collapse
Affiliation(s)
- William E Arter
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Aviad Levin
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Georg Krainer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK.
| |
Collapse
|
9
|
Stastna M. Continuous flow electrophoretic separation - Recent developments and applications to biological sample analysis. Electrophoresis 2019; 41:36-55. [PMID: 31650578 DOI: 10.1002/elps.201900288] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 01/23/2023]
Abstract
Continuous flow electrophoretic separation with continuous sample loading provides the advantage of processing volumes of any sizes, as well as the benefit of a real-time monitoring and optimization of the separation process. In addition, the spatial separation of the sample enables collecting multiple separated components simultaneously and in a continuous manner. The separation is usually performed in mild buffers without organic solvents and detergents (sample biological activity is retained) and it is carried out without usage of a solid support in the separation space preventing the interaction of the sample with it (high sample recovery). The method is used for the separation of proteins/peptides in proteomic applications, and its great applicability is to the separation of the cells, cellular organelles, vesicles, membrane fragments, and DNA. This review focuses on the electrophoretic separation performed in a continuous flow and it describes various electrophoretic modes and instrumental setups. Recent developments in methodology and instrumentation, the integration with other techniques, and the application to the biological sample analysis are discussed as well.
Collapse
Affiliation(s)
- Miroslava Stastna
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Brno, Czech Republic
| |
Collapse
|
10
|
Rudisch BM, Pfeiffer SA, Geissler D, Speckmeier E, Robitzki AA, Zeitler K, Belder D. Nonaqueous Micro Free-Flow Electrophoresis for Continuous Separation of Reaction Mixtures in Organic Media. Anal Chem 2019; 91:6689-6694. [DOI: 10.1021/acs.analchem.9b00714] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Benjamin M. Rudisch
- Institute of Analytical Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| | - Simon A. Pfeiffer
- Institute of Analytical Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| | - David Geissler
- Institute of Analytical Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| | - Elisabeth Speckmeier
- Institute of Organic Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| | - Andrea A. Robitzki
- Center for Biotechnology and Biomedicine, Leipzig University, Deutscher Platz 5, Leipzig 04103, Germany
| | - Kirsten Zeitler
- Institute of Organic Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| | - Detlev Belder
- Institute of Analytical Chemistry, Leipzig University, Johannisallee 29, Leipzig 04103, Germany
| |
Collapse
|
11
|
Zhou W, Xia L, Xiao X, Li G, Pu Q. A microchip device to enhance free flow electrophoresis using controllable pinched sample injections. Electrophoresis 2019; 40:2165-2171. [DOI: 10.1002/elps.201900079] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Wanjun Zhou
- School of Chemistry Sun Yat‐sen University Guangzhou P. R. China
| | - Ling Xia
- School of Chemistry Sun Yat‐sen University Guangzhou P. R. China
| | - Xiaohua Xiao
- School of Chemistry Sun Yat‐sen University Guangzhou P. R. China
| | - Gongke Li
- School of Chemistry Sun Yat‐sen University Guangzhou P. R. China
| | - Qiaosheng Pu
- Department of Chemistry Lanzhou University Lanzhou Gansu P. R. China
| |
Collapse
|
12
|
Flow rate independent gradient generator and application in microfluidic free-flow electrophoresis. Anal Chim Acta 2018; 1044:77-85. [DOI: 10.1016/j.aca.2018.04.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/19/2018] [Accepted: 04/26/2018] [Indexed: 11/19/2022]
|
13
|
Islinger M, Wildgruber R, Völkl A. Preparative free-flow electrophoresis, a versatile technology complementing gradient centrifugation in the isolation of highly purified cell organelles. Electrophoresis 2018; 39:2288-2299. [DOI: 10.1002/elps.201800187] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Markus Islinger
- Institute for Neuroanatomy, Centre for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim; University of Heidelberg; Heidelberg Germany
| | | | - Alfred Völkl
- Department of Medical Cell Biology; Institute of Anatomy; University of Heidelberg; Heidelberg Germany
| |
Collapse
|
14
|
Continuous purification of reaction products by micro free-flow electrophoresis enabled by large area deep-UV fluorescence imaging. Anal Bioanal Chem 2017; 410:853-862. [DOI: 10.1007/s00216-017-0697-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/18/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
|
15
|
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.
Collapse
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.
| |
Collapse
|
16
|
Novo P, Dell'Aica M, Jender M, Höving S, Zahedi RP, Janasek D. Integration of polycarbonate membranes in microfluidic free-flow electrophoresis. Analyst 2017; 142:4228-4239. [DOI: 10.1039/c7an01514c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A general difficulty in the miniaturization of free-flow electrophoresis relates to the need to separate electrodes and separation bed compartments.
Collapse
Affiliation(s)
- Pedro Novo
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| | - Margherita Dell'Aica
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| | - Matthias Jender
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| | - Stefan Höving
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| | - René P. Zahedi
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| | - Dirk Janasek
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V
- 44227 Dortmund
- Germany
| |
Collapse
|
17
|
Malá Z, Gebauer P, Boček P. Analytical capillary isotachophoresis after 50 years of development: Recent progress 2014-2016. Electrophoresis 2016; 38:9-19. [DOI: 10.1002/elps.201600289] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/15/2016] [Accepted: 07/15/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Zdena Malá
- Institute of Analytical Chemistry of the Czech Academy of Sciences; v.v.i; Brno Czech Republic
| | - Petr Gebauer
- Institute of Analytical Chemistry of the Czech Academy of Sciences; v.v.i; Brno Czech Republic
| | - Petr Boček
- Institute of Analytical Chemistry of the Czech Academy of Sciences; v.v.i; Brno Czech Republic
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|