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Gettler RC, Mehregan S, Koenig HD, Kaess AM, Young MJ. Nonequilibrium Anion Detection in Solid-Contact Ion-Selective Electrodes. ACS OMEGA 2024; 9:16443-16457. [PMID: 38617695 PMCID: PMC11007695 DOI: 10.1021/acsomega.4c00131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 04/16/2024]
Abstract
Low-cost and portable nitrate and phosphate sensors are needed to improve farming efficiency and reduce environmental and economic impact arising from the release of these nutrients into waterways. Ion selective electrodes (ISEs) could provide a convenient platform for detecting nitrate and phosphate, but existing ionophore-based nitrate and phosphate selective membrane layers used in ISEs are high cost, and ISEs using these membrane layers suffer from long equilibration time, reference potential drift, and poor selectivity. In this work, we demonstrate that constant current operation overcomes these shortcomings for ionophore-based anion-selective ISEs through a qualitatively different response mechanism arising from differences in ion mobility rather than differences in ion binding thermodynamics. We develop a theoretical treatment of phase boundary potential and ion diffusion that allows for quantitative prediction of electrode response under applied current. We also demonstrate that under pulsed current operation, we can create functional solid-contact ISEs using lower-cost molecularly imprinted polymers (MIPs). MIP-based nitrate sensors provide comparable selectivity against chloride to costlier ionophore-based sensors and exhibit >100,000 times higher selectivity against perchlorate. Likewise, MIP-based solid contact ion-selective electrode phosphate sensors operated under pulsed current provide competitive selectivity against chloride, nitrate, perchlorate, and carbonate anions. The theoretical treatment and conceptual demonstration of pulsed-current ISE operation we report will inform the development of new materials for membrane layers in ISEs based on differences in ion mobility and will allow for improved ISE sensor designs.
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Affiliation(s)
- Ryan C. Gettler
- Chemical
and Biomedical Engineering, University of
Missouri, Columbia, Missouri 65211, United States
| | - Shima Mehregan
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Henry D. Koenig
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Andie M. Kaess
- Chemical
and Biomedical Engineering, University of
Missouri, Columbia, Missouri 65211, United States
| | - Matthias J. Young
- Chemical
and Biomedical Engineering, University of
Missouri, Columbia, Missouri 65211, United States
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
- Materials
Science and Engineering Institute, University
of Missouri, Columbia, Missouri 65211, United States
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2
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Keresten V, Lazarev F, Mikhelson K. Transfer of Sodium Ion across Interface between Na +-Selective Electrode Membrane and Aqueous Electrolyte Solution: Can We Use Nernst Equation If Current Flows through Electrode? MEMBRANES 2024; 14:74. [PMID: 38668102 PMCID: PMC11052482 DOI: 10.3390/membranes14040074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/22/2024] [Accepted: 03/24/2024] [Indexed: 04/28/2024]
Abstract
Electrochemical impedance and chronopotentiometric measurements with Na+-selective solvent polymeric (PVC) membranes containing a neutral ionophore and a cation exchanger revealed low-frequency resistance, which is ascribed to Na+ ion transfer across the interface between the membrane and aqueous solution. The attribution is based on the observed regular dependence of this resistance on the concentration of Na+ in solutions. The respective values of the exchange current densities were found to be significantly larger than the currents flowing through ion-selective electrodes (ISEs) during an analysis in non-zero-current mode. This fact suggests that the interfacial electrochemical equilibrium is not violated by the current flow and implies that the Nernst equation can be applied to interpret the data obtained in non-zero-current mode, e.g., constant potential coulometry.
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Affiliation(s)
| | | | - Konstantin Mikhelson
- Chemistry Institute, St. Petersburg State University, 26 Universiteskij Pr., Stary Peterhof, 198504 St. Petersburg, Russia; (V.K.); (F.L.)
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3
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Dai HH, Cai X, Liu ZH, Xia RZ, Zhao YH, Liu YZ, Yang M, Li PH, Huang XJ. Ion-Electron Transduction Layer of the SnS 2-MoS 2 Heterojunction to Elevate Superior Interface Stability for All-Solid Sodium-Ion Selective Electrode. ACS Sens 2024; 9:415-423. [PMID: 38154098 DOI: 10.1021/acssensors.3c02185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
The high selectivity and fast ion response of all-solid sodium ion selective electrodes were widely applied in human sweat analysis. However, the potential drift due to insufficient interfacial capacitance leads to the deterioration of its stability and ultimately affects the potential accuracy of ion analysis. Designing a novel ion-electron transduction layer between the electrode and the ion selective membrane is an effective method to stabilize the interfacial potential. Herein, the SnS2-MoS2 heterojunction material was constructed by doping Sn in MoS2 nanosheets and used as the ion electron transduction layers of an all-solid sodium ion selective electrode for the first time, achieving the stable and efficient detection of Na+ ions. The proposed electrode exhibited a Nernst slope of 57.86 mV/dec for the detection of Na+ ions with a detection limit of 10-5.7 M in the activity range of 10-6-10-1 M. Via the electronic interaction at the heterojunction interfaces between SnS2 and MoS2 materials, the micro-nanostructure of the SnS2-MoS2 heterojunction was changed and SnS2-MoS2 as the ion-electron transduction layer acquired excellent capacitance (699 μF) and hydrophobicity (132°), resulting in a long-term potential stability of 1.37 μV/h. It was further proved that the large capacitance and high hydrophobicity of the ion-electron transduction layer are primary reasons for the excellent stability of the all-solid sodium ion selective electrode toward Na+ ions.
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Affiliation(s)
- Hai-Hua Dai
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Xin Cai
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zi-Hao Liu
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Rui-Ze Xia
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yong-Huan Zhao
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yang-Zhi Liu
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Meng Yang
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Pei-Hua Li
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Xing-Jiu Huang
- Key Laboratory of Environmental Optics and Technology and Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
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4
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Han T, Song T, Bao Y, Wang W, He Y, Liu Z, Gan S, Han D, Bobacka J, Niu L. Fast and sensitive coulometric signal transduction for ion-selective electrodes by utilizing a two-compartment cell. Talanta 2023; 262:124623. [PMID: 37244238 DOI: 10.1016/j.talanta.2023.124623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 05/29/2023]
Abstract
Here, we propose a fast and sensitive coulometric signal transduction method for ion-selective electrodes (ISEs) by utilizing a two-compartment cell. A potassium ion-selective electrode (K+-ISE) was connected as reference electrode (RE) and placed in the sample compartment. A glassy carbon (GC) electrode coated with poly(3,4-ethylenedioxythiophene) (GC/PEDOT), or reduced graphene oxide (GC/RGO), was connected as working electrode (WE) and placed in the detection compartment together with a counter electrode (CE). The two compartments were connected with an Ag/AgCl wire. The measured cumulated charge was amplified by increasing the capacitance of the WE. The observed slope of the cumulated charge with respect to the change of the logarithm of the K+ ion activity was linearly proportional to the capacitance of the GC/PEDOT and GC/RGO, estimated from impedance spectra. Furthermore, the sensitivity of the coulometric signal transduction using a commercial K+-ISE with internal filling solution as RE and GC/RGO as WE allowed to decrease the response time while still being able to detect a 0.2% change in K+ concentration. The coulometric method utilizing a two-compartment cell was found to be feasible for the determination of K+ concentrations in serum. The advantage of this two-compartment approach, compared to the coulometric transduction described earlier, was that no current passed through the K+-ISE that was connected as RE. Therefore, current-induced polarization of the K+-ISE was avoided. Furthermore, since the GCE/PEDOT and GCE/RGO (used as WE) had a low impedance, the response time of the coulometric response decreased from minutes to seconds.
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Affiliation(s)
- Tingting Han
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
| | - Tao Song
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, PR China
| | - Yu Bao
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
| | - Wei Wang
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China.
| | - Ying He
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
| | - Zhenbang Liu
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
| | - Shiyu Gan
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China.
| | - Dongxue Han
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China; Guangdong Provincial Key Laboratory of Psychoactive Substances Monitoring and Safety, Anti-Drug Technology Center of Guangdong Province, Guangzhou, 510230, PR China
| | - Johan Bobacka
- Åbo Akademi University, Johan Gadolin Process Chemistry Centre, Laboratory of Molecular Science and Engineering, Henriksgatan 2, FI-20500, Turku/Åbo, Finland
| | - Li Niu
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, C/o School of Chemistry and Chemical Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
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5
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Miškinis J, Ramonas E, Gurevičienė V, Razumienė J, Dagys M, Ratautas D. Capacitance-Based Biosensor for the Measurement of Total Loss of L-Amino Acids in Human Serum during Hemodialysis. ACS Sens 2022; 7:3352-3359. [PMID: 36268654 PMCID: PMC9706805 DOI: 10.1021/acssensors.2c01342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In this paper, we present a biosensor based on a gold nanoparticle (AuNP)-modified Pt electrode with an adjusted membrane containing cross-linked L-amino acid oxidase for the detection and quantification of total L-amino acids. The designed biosensor was tested and characterized using the capacitance-based principle, capacitance measurements after electrode polarization, disconnection from the circuit, and addition of the respective amount of the analyte. The method was implemented using the capacitive and catalytic properties of the Pt/AuNP electrode; nanostructures were able to store electric charge while at the same time catalyzing the oxidation of the redox reaction intermediate H2O2. In this way, the Pt/AuNP layer was charged after the addition of analytes, allowing for much more accurate measurements for samples with low amino acid concentrations. The combined biosensor electrode with the capacitance-based measurement method resulted in high sensitivity and a low limit of detection (LOD) for hydrogen peroxide (4.15 μC/μM and 0.86 μM, respectively) and high sensitivity, a low LOD, and a wide linear range for L-amino acids (0.73 μC/μM, 5.5 μM and 25-1500 μM, respectively). The designed biosensor was applied to measure the relative loss of amino acids in patients undergoing renal replacement therapy by analyzing amino acid levels in diluted serum samples before and after entering/leaving the hemodialysis apparatus. In general, the designed biosensor in conjunction with the proposed capacitance-based method was clinically tested and could also be applied for the detection of other analytes using analyte-specific oxidases.
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6
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Wu Y, Bakker E. Self-Powered Signal Transduction of Ion-Selective Electrodes to an Electronic Paper Display. ACS Sens 2022; 7:3201-3207. [PMID: 36251606 DOI: 10.1021/acssensors.2c01826] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mobile integrated electrochemical sensors normally require a power supply for operation. Unfortunately, the practice of discarding batteries associated with these devices runs counter to our desire for a sustainable world. Self-powered sensing concepts that draw the energy directly from the measurement itself would overcome this limitation. Potentiometric sensors for the measurement of pH, many electrolytes, and gases are ubiquitous in analytical practice. However, in potentiometry, the voltage is acquired in the absence of current flow, making it seemingly impossible to draw power. Fortunately, it has been recently established that transient currents may be tolerated across potentiometric measurement cells to charge a capacitive or electrochromic element such as Prussian blue integrated in the measurement cell and whose absorbance then directly follows the potential changes in a reversible manner. We have shown here that commercial electronic paper (e-paper), widely used to make electronic ink and ebook readers, can directly be driven by a potentiometric measurement cell in a reversible manner at mild potentials of >100 mV typical for such sensors. The capacitance of the e-paper pixel studied here was found to be 0.53 μF mm-2, 30 times smaller than that of Prussian blue films. The colorimetric absorbance of the e-paper was also more stable (observed drift over 2 h corresponding to 0.76 mV h-1) and reproducible (corresponding to 1 mV standard deviation). The e-paper pixel was directly driven by a polymeric pH electrode as a model system. Choosing a basic inner solution (pH 12.9) behind the membrane gave sufficiently positive cell potentials for driving visible absorbance change in a sample pH range of 4-10, while a more acidic pH of 3.4 and alternating the connections to the e-paper were more suited for more basic samples of pH > 10. This convenient and cost-effective approach makes it possible to directly drive an optical display from the potentiometric measurement itself and should be suitable for moderate sensing membrane resistances of less than about 100 kΩ, depending on the area of the chosen pixel.
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Affiliation(s)
- Yaotian Wu
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211Geneva, Switzerland
| | - Eric Bakker
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211Geneva, Switzerland
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7
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Han T, Song T, Bao Y, Sun Z, Ma Y, He Y, Gan S, Jiang D, Han D, Bobacka J, Niu L. Amperometric response of solid-contact ion-selective electrodes utilizing a two-compartment cell and a redox couple in solution. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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8
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Lyu Y, Han T, Zhong L, Tang Y, Xu L, Ma Y, Bao Y, Gan S, Bobacka J, Niu L. Coulometric ion sensing with Li+-selective LiMn2O4 electrodes. Electrochem commun 2022. [DOI: 10.1016/j.elecom.2022.107302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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9
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Bondar AV, Keresten VM, Mikhelson KN. Ionophore-Based Ion-Selective Electrodes in Non-Zero Current Modes: Mechanistic Studies and the Possibilities of the Analytical Application. JOURNAL OF ANALYTICAL CHEMISTRY 2022. [DOI: 10.1134/s1061934822020046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
This mini review briefly describes (i) literature data on the non-zero current measurements with ionophore-based ion-selective electrodes (ISEs) aimed at fundamental studies of the mechanism of their potentiometric response, and (ii) the data on the possibilities of analytical applications of ISEs in voltametric and constant potential chronoamperometric/coulometric modes, in particular the K+ ion assay in blood serum with the sensitivity of 0.1%. A special attention is paid to the basics of voltammetry and chronoamperometry/coulometry with the ionophore-based ISEs, and to how and why these methods differ from the classical voltammetry and coulometry.
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10
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Bondar A, Mikhelson K. Constant Potential Coulometric Measurements with Ca 2+-Selective Electrode: Analysis Using Calibration Plot vs. Analysis Using the Charge Curve Fitting. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22031145. [PMID: 35161889 PMCID: PMC8838552 DOI: 10.3390/s22031145] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/29/2022] [Accepted: 01/31/2022] [Indexed: 06/01/2023]
Abstract
The possibility of analysis using charge curve fitting in constant potential coulometric mode instead of using a calibration plot is explored, for the first time. The results are compared with the analysis based on the use of a calibration plot. A Ca2+ ion-selective electrode, with and without an electronic capacitor in series, is used as a model system in pure solutions of CaCl2. Both techniques delivered good results (error within 2%) when the final and the initial concentration values differed by not more than three times. Larger differences result in 10-25% error. The presence of an electronic capacitor in the measurement circuit and in series with the electrode, allows for significantly faster response.
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Abstract
Potentiometric sensors induce a spontaneous voltage that indicates ion activity in real time. We present here an advanced self-powered potentiometric sensor with memory. Specifically, the approach allows for one to record a deviation from the analyte's original concentration or determine whether the analyte concentration has surpassed a threshold in a predefined time interval. The sensor achieves this by harvesting energy in a capacitor and preserving it with the help of a diode. While the analyte concentration is allowed to return to an original value following a perturbation over time, this may not influence the sensor readout. To achieve the diode function, the sensor utilizes an additional pair of driving electrodes to move the potentiometric signal to a sufficiently high base voltage that is required for operating the diode placed in series with the capacitor and between the sensing probes. A single voltage measurement across the capacitor at the end of a chosen time interval is sufficient to reveal any altered ion activity occurring during that period. We demonstrate the applicability of the sensor to identify incurred pH changes in a river water sample during an interval of 2 h. This approach is promising for achieving deployable sensors to monitor ion activity relative to a defined threshold during a time interval with minimal electronic components in a self-powered design.
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Affiliation(s)
- Sunil Kumar Sailapu
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), C/del Til·lers, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Neus Sabaté
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), C/del Til·lers, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), P.L. Companys 23, 08010 Barcelona, Spain
| | - Eric Bakker
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
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Using MoS2/Fe3O4 as Ion-Electron Transduction Layer to Manufacture All-Solid-State Ion-Selective Electrode for Determination of Serum Potassium. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9070155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
As an essential electrolyte for the human body, the potassium ion (K+) plays many physiological roles in living cells, so the rapid and accurate determination of serum K+ is of great significance. In this work, we developed a solid-contact ion-selective electrode (SC-ISE) using MoS2/Fe3O4 composites as the ion-to-electron transducer to determine serum K+. The potential response measurement of MoS2/Fe3O4/K+-ISE shows a Nernst response by a slope of 55.2 ± 0.1 mV/decade and a low detection limit of 6.3 × 10−6 M. The proposed electrode exhibits outstanding resistance to the interference of O2, CO2, light, and water layer formation. Remarkably, it also presents a high performance in potential reproducibility and long-term stability.
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13
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Light-driven ion extraction of polymeric membranes for on-demand Cu(II) sensing. Anal Chim Acta 2021; 1176:338756. [PMID: 34399898 DOI: 10.1016/j.aca.2021.338756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/26/2021] [Accepted: 06/11/2021] [Indexed: 11/21/2022]
Abstract
The modulation of the ion-fluxes across a polymeric membrane is important for designing attractive methodologies. As an alternative to the commonly used dynamic electrochemistry approaches, light can be used as an external stimulus and provides a very convenient way to manipulate ions release and/or extraction into a polymeric membrane. Herein, we designed a solid-contact polymeric membrane ion-selective sensor that exhibits dynamic response by light irradiation at 375 nm. The electrode membrane contains a light-sensitive lipophilic salt (bis(4-tert-butylphenyl)iodonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (R+-R-, BTDT-TFPB) instead of traditional ion exchanger. Under light illumination, the decomposition of the lipophilic cation makes the membrane with ion-exchange properties. The solid-contact ion-selective electrodes based on potentiometry and constant potential coulometry have been explored for direct ion sensing. Copper was selected as a mode analyte and can be determined at micromole levels. The proposed dynamic ion sensors show promise for on-demand ion sensing.
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Keresten V, Solovyeva E, Mikhelson K. The Origin of the Non-Constancy of the Bulk Resistance of Ion-Selective Electrode Membranes within the Nernstian Response Range. MEMBRANES 2021; 11:membranes11050344. [PMID: 34067145 PMCID: PMC8150337 DOI: 10.3390/membranes11050344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 11/16/2022]
Abstract
The dependence of the bulk resistance of membranes of ionophore-based ion-selective electrodes (ISEs) on the composition of mixed electrolyte solutions, within the range of the Nernstian potentiometric response, is studied by chronopotentiometric and impedance measurements. In parallel to the resistance, water uptake by the membranes is also studied gravimetrically. The similarity of the respective curves is registered and explained in terms of heterogeneity of the membranes due to the presence of dispersed aqueous phase (water droplets). It is concluded that the electrochemical equilibrium is established between aqueous solution and the continuous organic phase, while the resistance refers to the membrane as whole, and water droplets hamper the charge transfer across the membranes. In this way, it is explained why the membrane bulk resistance is not constant within the range of the Nernstian potentiometric response of ISEs.
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15
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Zdrachek E, Bakker E. Ion-to-electron capacitance of single-walled carbon nanotube layers before and after ion-selective membrane deposition. Mikrochim Acta 2021; 188:149. [PMID: 33797650 PMCID: PMC8018922 DOI: 10.1007/s00604-021-04805-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/21/2021] [Indexed: 01/26/2023]
Abstract
The capacitance of the ion-to-electron transducer layer helps to maintain a high potential stability of solid-contact ion-selective electrodes (SC-ISEs), and its estimation is therefore an essential step of SC-ISE characterization. The established chronopotentiometric protocol used to evaluate the capacitance of the single-walled carbon nanotube transducer layer was revised in order to obtain more reliable and better reproducible values and also to allow capacitance to be measured before membrane deposition for electrode manufacturing quality control purposes. The capacitance values measured with the revised method increased linearly with the number of deposited carbon nanotube-based transducer layers and were also found to correlate linearly before and after ion-selective membrane deposition, with correlation slopes close to 1 for nitrate-selective electrodes, to 0.7 and to 0.5 for potassium- and calcium-selective electrodes.
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Affiliation(s)
- Elena Zdrachek
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211, Geneva, Switzerland.
| | - Eric Bakker
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211, Geneva, Switzerland.
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16
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Affiliation(s)
- Elena Zdrachek
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
| | - Eric Bakker
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
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