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Hu C, Xie B, Li H, Xiao D. A five-electrode capacitively coupled contactless conductivity detector with a low limit of detection. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:2253-2261. [PMID: 37128967 DOI: 10.1039/d3ay00328k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The conductivity detector is a broadly used device that allows for the highly efficient detection of analytes, and continuous efforts have been directed toward lowering the limit of detection. In this study, a five-electrode capacitively coupled contactless conductivity detector (TIC4D) is proposed, which uses copper mesh between the electrodes for a grounding shield to reduce the interference of stray capacitance and noise. After adding the copper mesh shield, the difference value between the response signal and baseline at low KCl concentration is effectively increased, achieving 33 mV for 10-9 M KCl solution. Meanwhile, for the unshielded detector, the difference is only 18 mV for the KCl solution at the same concentration. The response signal shows a linear function of the logarithm at the range of 10-4 M to 10-5 M KCl solution, and the TIC4D detector displays a higher slope (0.8448) than the conventional single-input capacitively coupled contactless conductivity detector (C4D: 0.5579) and dual-input capacitively coupled contactless conductivity detectors (DIC4D: 0.6173). Moreover, two TIC4D detectors are combined to achieve a dual-channel six-input differential capacitively coupled contactless conductivity detector (SIDC4D), reducing the high baseline levels caused by the multi-signal input. By differentially amplifying the output signal, the high baseline levels and noise interference can be effectively reduced. For the 10-3 M KCl solution, the ratio of the response signal to baseline for SIDC4D can reach 8.500, almost 7 times that of TIC4D, and a lower limit of detection (LOD) of 3 × 10-10 M is also achieved. This work may open a new door based on coupled contactless conductivity for detection performance.
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Affiliation(s)
- Chunqiong Hu
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Bo Xie
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
| | - Hongmei Li
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Dan Xiao
- College of Chemical Engineering, Sichuan University, Chengdu 610064, China.
- College of Chemistry, Sichuan University, Chengdu 610064, China
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A Novel Planar Grounded Capacitively Coupled Contactless Conductivity Detector for Microchip Electrophoresis. MICROMACHINES 2022; 13:mi13030394. [PMID: 35334684 PMCID: PMC8953769 DOI: 10.3390/mi13030394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/19/2022] [Accepted: 02/25/2022] [Indexed: 11/30/2022]
Abstract
In the microchip electrophoresis with capacitively coupled contactless conductivity detection, the stray capacitance of the detector causes high background noise, which seriously affects the sensitivity and stability of the detection system. To reduce the effect, a novel design of planar grounded capacitively coupled contactless conductivity detector (PG-C4D) based on printed circuit board (PCB) is proposed. The entire circuit plane except the sensing electrodes is covered by the ground electrode, greatly reducing the stray capacitance. The efficacy of the design has been verified by the electrical field simulation and the electrophoresis detection experiments of inorganic ions. The baseline intensity of the PG-C4D was less than 1/6 of that of the traditional C4D. The PG-C4D with the new design also demonstrated a good repeatability of migration time, peak area, and peak height (n = 5, relative standard deviation, RSD ≤ 0.3%, 3%, and 4%, respectively), and good linear coefficients within the range of 0.05–0.75 mM (R2 ≥ 0.986). The detection sensitivity of K+, Na+, and Li+ reached 0.05, 0.1, and 0.1 mM respectively. Those results prove that the new design is an effective and economical approach which can improve sensitivity and repeatability of a PCB based PG-C4D, which indicate a great application potential in agricultural and environmental monitoring.
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Poboży E, Trojanowicz M. Application of Capillary Electrophoresis for Determination of Inorganic Analytes in Waters. Molecules 2021; 26:6972. [PMID: 34834063 PMCID: PMC8625978 DOI: 10.3390/molecules26226972] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022] Open
Abstract
Aside from HPLC and GC, capillary electrophoresis (CE) is one of the most important techniques for high-performance separations in modern analytical chemistry. Its main advantages are the possibility of using different detection techniques, the possibility of in-capillary sample processing for preconcentration or derivatization, and ease of instrumental miniaturization down to the microfluidic scale. Those features are utilized in the separation of macromolecules in biochemistry and in genetic investigations, but they can be also used in determinations of inorganic ions in water analysis. This review, based on about 100 original research works, presents applications of CE methods in water analysis reported in recent decade, mostly regarding conductivity detection or indirect UV detection. The developed applications include analysis of high salinity sea waters, as well as analysis of other surface waters and drinking waters.
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Affiliation(s)
- Ewa Poboży
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - Marek Trojanowicz
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
- Laboratory of Nuclear Analytical Techniques, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
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Chau MK, Arega NG, Nhung Tran NA, Song J, Lee S, Kim J, Chung M, Kim D. Capacitively coupled contactless conductivity detection for microfluidic capillary isoelectric focusing. Anal Chim Acta 2020; 1124:60-70. [PMID: 32534676 DOI: 10.1016/j.aca.2020.05.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/25/2020] [Accepted: 05/09/2020] [Indexed: 12/30/2022]
Abstract
We report capacitively coupled contactless conductivity detection (C4D) of proteins separated by microfluidic capillary isoelectric focusing (μCIEF). To elucidate the evolution of negative conductivity peaks during focusing and seek IEF conditions for sensitive conductivity detection, numerical simulation was performed using a model protein GFP (green fluorescence protein) and hypothetical carrier ampholytes (CAs). C4D was successfully applied to the μCIEF by optimizing assay conditions using a simple and effective pressure-mobilization approach. The conductivity and fluorescence signals of a focused GFP band were co-detected, confirming that the obtained negative C4D peak could be attributed to the actual protein, not the non-uniform background conductivity profile of the focused CAs. GFP concentrations of 10 nM-30 μM was quantified with a detection limit of 10 nM. Finally, the resolving power was analyzed by separating a mixture of R-phycoerythrin (pI 5.01), GFP-F64L (pI 5.48), and RK-GFP (pI 6.02). The conductivities of the three separated fluorescence proteins were measured with average separation resolution of 2.06. We expect the newly developed label-free μCIEF-C4D technique to be widely adopted as a portable, electronics-only protein-analysis tool.
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Affiliation(s)
- Minh Khang Chau
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Nebiyu Getachew Arega
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Nguyen Anh Nhung Tran
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Jin Song
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Sangmin Lee
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Jintae Kim
- Department of Electrical Engineering, Konkuk University, Gwangjin-gu, Seoul, 05029, South Korea
| | - Minsub Chung
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Dohyun Kim
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea; Natural Science Research Institute, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea.
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Tang M, Xu J, Xu Z. Simultaneous determination of metal ions by capillary electrophoresis with contactless conductivity detection and insights into the effects of BGE component. Microchem J 2019. [DOI: 10.1016/j.microc.2019.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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HUANG Z, YANG M, YOU H, XIE Y. Simultaneous Determination of Inorganic Cations and Anions in Microchip Electrophoresis Using High-voltage Relays. ANAL SCI 2018; 34:801-805. [DOI: 10.2116/analsci.18p022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Zhe HUANG
- Institute of Intelligent Machines, Chinese Academy of Sciences
- Department of Instruments Science and Engineering, University of Science and Technology of China
| | - Mingpeng YANG
- Institute of Intelligent Machines, Chinese Academy of Sciences
- Department of Instruments Science and Engineering, University of Science and Technology of China
| | - Hui YOU
- Institute of Intelligent Machines, Chinese Academy of Sciences
- Department of Instruments Science and Engineering, University of Science and Technology of China
| | - Yang XIE
- Institute of Intelligent Machines, Chinese Academy of Sciences
- Department of Instruments Science and Engineering, University of Science and Technology of China
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YANG MP, HUANG Z, XIE Y, YOU H. Development of Microchip Electrophoresis and Its Applications in Ion Detection. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(18)61085-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20th anniversary of axial capacitively coupled contactless conductivity detection in capillary electrophoresis. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.03.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Drevinskas T, Telksnys L, Maruška A, Gorbatsova J, Kaljurand M. Capillary Electrophoresis Sensitivity Enhancement Based on Adaptive Moving Average Method. Anal Chem 2018; 90:6773-6780. [DOI: 10.1021/acs.analchem.8b00664] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tomas Drevinskas
- Instrumental Analysis Open Access Centre, Faculty of Natural Sciences, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania
- Department of Systems’ Analysis, Faculty of Informatics, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania
| | - Laimutis Telksnys
- Department of Systems’ Analysis, Faculty of Informatics, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania
- Recognition Processes Department, Institute of Mathematics and Informatics, Goštauto 12, LT01108 Vilnius, Lithuania
| | - Audrius Maruška
- Instrumental Analysis Open Access Centre, Faculty of Natural Sciences, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania
| | - Jelena Gorbatsova
- Department of Chemistry, Faculty of Sciences, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Mihkel Kaljurand
- Instrumental Analysis Open Access Centre, Faculty of Natural Sciences, Vytautas Magnus University, Vileikos 8, LT44404 Kaunas, Lithuania
- Department of Chemistry, Faculty of Sciences, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
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Kecskemeti A, Gaspar A. Particle-based immobilized enzymatic reactors in microfluidic chips. Talanta 2018; 180:211-228. [DOI: 10.1016/j.talanta.2017.12.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
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Wuethrich A, Quirino JP. Sensitivity enhancing injection from a sample reservoir and channel interface in microchip electrophoresis. J Sep Sci 2017; 40:927-932. [DOI: 10.1002/jssc.201601064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/08/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Alain Wuethrich
- Australian Centre for Research on Separation Science (ACROSS) School of Physical Sciences‐Chemistry University of Tasmania Hobart TAS 7001 Australia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation Science (ACROSS) School of Physical Sciences‐Chemistry University of Tasmania Hobart TAS 7001 Australia
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Kubáň P, Hauser PC. Contactless conductivity detection for analytical techniques- Developments from 2014 to 2016. Electrophoresis 2016; 38:95-114. [DOI: 10.1002/elps.201600280] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/05/2016] [Accepted: 08/06/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Pavel Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences; Brno Czech Republic
| | - Peter C. Hauser
- Department of Chemistry; University of Basel; Basel Switzerland
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Koczka PI, Bodor R, Masár M, Gáspár A. Application of isotachophoresis in commercial capillary electrophoresis instrument using C4D and UV detection. Electrophoresis 2016; 37:2384-92. [DOI: 10.1002/elps.201600194] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/18/2016] [Accepted: 06/07/2016] [Indexed: 01/27/2023]
Affiliation(s)
- Péter I. Koczka
- Department of Inorganic and Analytical Chemistry; University of Debrecen; Debrecen Hungary
| | - Róbert Bodor
- Department of Analytical Chemistry, Faculty of Natural Sciences; Comenius University in Bratislava; Bratislava Slovakia
| | - Marián Masár
- Department of Analytical Chemistry, Faculty of Natural Sciences; Comenius University in Bratislava; Bratislava Slovakia
| | - Attila Gáspár
- Department of Inorganic and Analytical Chemistry; University of Debrecen; Debrecen Hungary
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