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Li Z, Chande C, Cheng YH, Basuray S. Recent State and Challenges in Spectroelectrochemistry with Its Applications in Microfluidics. MICROMACHINES 2023; 14:667. [PMID: 36985074 PMCID: PMC10056660 DOI: 10.3390/mi14030667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/12/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
This review paper presents the recent developments in spectroelectrochemical (SEC) technologies. The coupling of spectroscopy and electrochemistry enables SEC to do a detailed and comprehensive study of the electron transfer kinetics and vibrational spectroscopic fingerprint of analytes during electrochemical reactions. Though SEC is a promising technique, the usage of SEC techniques is still limited. Therefore, enough publicity for SEC is required, considering the promising potential in the analysis fields. Unlike previously published review papers primarily focused on the relatively frequently used SEC techniques (ultraviolet-visible SEC and surface-enhanced Raman spectroscopy SEC), the two not-frequently used but promising techniques (nuclear magnetic resonance SEC and dark-field microscopy SEC) have also been studied in detail. This review paper not only focuses on the applications of each SEC method but also details their primary working mechanism. In short, this paper summarizes each SEC technique's working principles, current applications, challenges encountered, and future development directions. In addition, each SEC technique's applicative research directions are detailed and compared in this review work. Furthermore, integrating SEC techniques into microfluidics is becoming a trend in minimized analysis devices. Therefore, the usage of SEC techniques in microfluidics is discussed.
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Affiliation(s)
- Zhenglong Li
- Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Charmi Chande
- Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Yu-Hsuan Cheng
- Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Sagnik Basuray
- Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
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2
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Ferreira da Silva P, Santana Ribeiro T, Ferreira Gomes B, Tiago dos Santos Tavares da Silva G, Silva Lobo CM, Carmo M, Ribeiro C, Bernardes Filho R, Roth C, Colnago LA. Miniaturized Carbon Fiber Paper Electrodes for In Situ High Resolution NMR Analyses. Anal Chem 2022; 94:15223-15230. [DOI: 10.1021/acs.analchem.2c02058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pollyana Ferreira da Silva
- Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590São Carlos, SP, Brazil
- Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428Jülich, Germany
| | - Tatiana Santana Ribeiro
- Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428Jülich, Germany
- Department of Natural Science, Mathematics and Education, Federal University of São Carlos, Rodovia Anhanguera, Km 174, SP-330, 13600-970Araras, SP, Brazil
| | - Bruna Ferreira Gomes
- Electrochemical Process Engineering, University of Bayreuth, Universitätsstraße 30, 95447Bayreuth, Germany
| | | | - Carlos Manuel Silva Lobo
- Institute of Technical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569Stuttgart, Germany
| | - Marcelo Carmo
- Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428Jülich, Germany
| | - Cauê Ribeiro
- Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428Jülich, Germany
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13561-206São Carlos, SP, Brazil
| | | | - Christina Roth
- Electrochemical Process Engineering, University of Bayreuth, Universitätsstraße 30, 95447Bayreuth, Germany
| | - Luiz Alberto Colnago
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13561-206São Carlos, SP, Brazil
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3
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Use of Time Domain Nuclear Magnetic Resonance Relaxometry to Monitor the Effect of Magnetic Field on the Copper Corrosion Rate in Real Time. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The corrosion of metals is a major problem of modern societies, demanding new technologies and studies to understand and minimize it. Here we evaluated the effect of a magnetic field (B) on the corrosion of copper in aqueous HCl solution under open circuit potential. The corrosion product, Cu2+, is a paramagnetic ion and its concentration in the solution was determined in real time in the corrosion cell by time-domain NMR relaxometry. The results show that the magnetic field (B = 0.23 T) of the time-domain NMR instrument reduces the corrosion rate by almost 50%, in comparison to when the corrosion reaction is performed in the absence of B. Atomic force microscopy and X-ray diffraction results of the analysis of the corroded surfaces reveal a detectable CuCl phase and an altered morphology when B is present. The protective effect of B was explained by magnetic forces that maintain the Cu2+ in the solution/metal interface for a longer time, hindering the arrival of the new corrosive agents, and leading to the formation of a CuCl phase, which may contribute to the rougher surface. The time-domain NMR method proved to be useful to study the effect of B in the corrosion of other metals or other corrosive liquid media when the reactions produce or consume paramagnetic ions.
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Ferreira da Silva P, Ferreira Gomes B, Silva Lobo CM, Carmo M, Roth C, Colnago LA. Composite Graphite-Epoxy Electrodes for In Situ Electrochemistry Coupling with High Resolution NMR. ACS OMEGA 2022; 7:4991-5000. [PMID: 35187316 PMCID: PMC8851621 DOI: 10.1021/acsomega.1c05823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
The in situ coupling between electrochemistry and spectrometric techniques can help in the identification and quantification of the compounds produced and consumed during electrochemical reactions. The combination of electrochemistry with nuclear magnetic resonance is quite attractive in this respect, but it has some challenges to be addressed, namely, the reduction in the quality of the NMR signal when the metallic electrodes are placed close to or in the detection region. Since NMR is not a passive technique, the convective effect of the magnetic force (magnetoelectrolysis), which acts by mixing the solution and increasing the mass transport, has to be considered. In seeking to solve the aforementioned problems, we developed a system of miniaturized electrodes inside a 5 mm NMR tube (outer diameter); the working and counter electrodes were prepared with a mixture of graphite powder and epoxy resin. To investigate the performance of the electrodes, the benzoquinone reduction to hydroquinone and the isopropanol oxidation to acetone were monitored. To monitor the alcohol oxidation reaction, the composite graphite-epoxy electrode (CGEE) surface was modified through platinization. The electrode was efficient for in situ monitoring of the aforementioned reactions, when positioned 1 mm above the detection region of the NMR spectrometer. The magnetoelectrolysis effect acts by stirring the solution and increases the reaction rate of the reduction of benzoquinone, because this reaction is limited by mass transport, while no effect on the reaction rate is observed for the isopropanol oxidation reaction.
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Affiliation(s)
- Pollyana Ferreira da Silva
- Instituto
de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590, São Carlos, SP Brazil
| | - Bruna Ferreira Gomes
- Instituto
de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590, São Carlos, SP Brazil
| | - Carlos Manuel Silva Lobo
- Instituto
de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense, 400, 13566-590, São Carlos, SP Brazil
| | - Marcelo Carmo
- Forschungszentrum
Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Christina Roth
- Electrochemical
Process Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Luiz Alberto Colnago
- Embrapa
Instrumentação, Rua XV de Novembro, 1452, 13560-970 São Carlos, SP Brazil
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One-Pot Synthesis of Carboxymethylcellulose-Templated Copper-NPs for Heterocatalytic Huisgen-Click Reactions on Lignocellulosic Bamboo Slices. Catal Letters 2022. [DOI: 10.1007/s10562-022-03923-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Facchinatto WM, Dos Santos Garcia RH, Dos Santos DM, Fiamingo A, Menezes Flores DW, Campana-Filho SP, de Azevedo ER, Colnago LA. Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan. Carbohydr Polym 2021; 256:117576. [PMID: 33483071 DOI: 10.1016/j.carbpol.2020.117576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 12/11/2020] [Accepted: 12/27/2020] [Indexed: 11/19/2022]
Abstract
Chitosans with different average degrees of acetylation and weight molecular weight were analyzed by time-domain NMR relaxometry using the recently proposed pulse sequence named Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE) to acquire 1H NMR signal of solid-state materials. The NMR signal decay was composed of faster (tenths of μs) and longer components, where the mobile-part fraction exhibited an effective relaxation transverse time assigned to methyl hydrogens from N-acetyl-d-glucosamine (GlcNAc) units. The higher intrinsic mobility of methyl groups was confirmed via DIPSHIFT experiments by probing the 1H-13C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R2 > 0.93) between RK-ROSE signal profile and average degrees of acetylation and crystallinity index, thus indicating that time-domain NMR consists in a promising tool for structural and morphological characterization of chitosan.
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Affiliation(s)
- William Marcondes Facchinatto
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil.
| | - Rodrigo Henrique Dos Santos Garcia
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Danilo Martins Dos Santos
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
| | - Anderson Fiamingo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Douglas William Menezes Flores
- Superior College of Agriculture "Luiz de Queiroz", University of Sao Paulo, Av. Padua Dias 11, CEP 13418-900, Caixa Postal 9, Piracicaba, SP, Brazil
| | - Sérgio Paulo Campana-Filho
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Eduardo Ribeiro de Azevedo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Luiz Alberto Colnago
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
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7
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Benders S, Gomes BF, Carmo M, Colnago LA, Blümich B. In-situ MRI velocimetry of the magnetohydrodynamic effect in electrochemical cells. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 312:106692. [PMID: 32062585 DOI: 10.1016/j.jmr.2020.106692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/25/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
Electrochemical reactions have become increasingly important in a large number of processes and applications. The use of NMR (Nuclear Magnetic Resonance) techniques to follow in situ electrochemistry processes has been gaining increasing attention from the scientific community because they allow the identification and quantification of the products and reagents, whereas electrochemistry measurements alone are not able to do so. However, when an electrochemical reaction is performed in situ the reaction rate can be increased by action of the Lorentz force, which is equal to the cross product between the current density and the magnetic field applied. This phenomenon is called the magnetohydrodynamic (MHD) effect. Although this process is beneficial because it accelerates the reaction, it needs to be well understood and taken into account during the in situ electrochemical measurements. The MHD effect is based on increased mass transfer, which is shown by in situ MRI velocimetry here. Images had to be acquired in a rapid manner since current was not pulsed. Significant velocities in a plane parallel to the electrodes alongside with complex flow patterns were detected.
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Affiliation(s)
- Stefan Benders
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52064 Aachen, Germany.
| | - Bruna Ferreira Gomes
- Universidade de São Paulo, Instituto de Quĩmica de São Carlos, Av. Trab. São Carlense, 400 - Parque Arnold Schimidt, São Carlos, SP 13566-590, Brazil; Universität Bayreuth, Fakultät für Ingenieurwissenschaften, Lehrstuhl für Werkstoffverfahrenstechnik, 95447 Bayreuth, Germany
| | - Marcelo Carmo
- Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Luiz Alberto Colnago
- Embrapa Instrumentação, Rua 15 de Novembro, 1452 - Centro, São Carlos, SP 13560-970, Brazil
| | - Bernhard Blümich
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52064 Aachen, Germany
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8
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Silva PFD, Gomes BF, Lobo CMS, Queiroz Júnior LHK, Danieli E, Carmo M, Blümich B, Colnago LA. Electrochemical NMR spectroscopy: Electrode construction and magnetic sample stirring. Microchem J 2019. [DOI: 10.1016/j.microc.2019.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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9
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Lobo CM, Gomes BF, Bouzouma H, Danieli E, Blümich B, Colnago LA. Improving in operando low field NMR copper electrodeposition analyses using inductively coupled coils. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.12.076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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10
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Monitoring Electrochemical Reactions in Situ with Low Field NMR: A Mini-Review. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The number of applications of time domain NMR using low-field spectrometers in research and development has been steadily increasing in recent years with applications ranging from quality control of industrial products to the study of physical and chemical properties of a wide array of solid and liquid samples to, most recently, electrochemical studies. In this mini-review we summarize the progress that has been achieved in the coupling between time domain NMR (using low-field spectrometers) and electrochemistry and how the challenges that this coupling poses have been overcome over the years. We also highlight the effect that the static magnetic field of the NMR spectrometer has on the electrochemical systems.
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Serial M, Velasco MI, Maldonado Ochoa SA, Zanotto FM, Dassie SA, Acosta RH. Magnetic Resonance Imaging in Situ Visualization of an Electrochemical Reaction under Forced Hydrodynamic Conditions. ACS OMEGA 2018; 3:18630-18638. [PMID: 31458430 PMCID: PMC6643744 DOI: 10.1021/acsomega.8b02460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/18/2018] [Indexed: 06/10/2023]
Abstract
Magnetic resonance imaging (MRI) has proven to be a powerful tool for the characterization and investigation of in situ chemical reactions. This is more relevant when dealing with complex systems, where the spatial distribution of the species, partition equilibrium, flow patterns, among other factors have a determining effect over mass transport and therefore over the reaction rate. The advantage of MRI is that it provides spatial information in a noninvasive way and does not require any molecular sensor or sample extraction. In this work, MRI is used to fully characterize an electrochemical reaction under forced hydrodynamic conditions. Reaction rates, flow patterns, and quantitative concentration of the chemical species involved are spatially monitored in situ in a complex system that involves metallic pieces and a heterogeneous cementation reaction. Experimental data are compared with numerical simulations.
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Affiliation(s)
- María
Raquel Serial
- Facultad
de Matemática, Física, Astronomía y Computación, Universidad Nacional de Córdoba, Medina Allende s/n, X5000HUA Córdoba, Argentina
- Instituto
de Física Enrique Gaviola (IFEG), CONICET, Medina Allende
s/n, X5000HUA, Córdoba, Argentina
| | - Manuel Isaac Velasco
- Facultad
de Matemática, Física, Astronomía y Computación, Universidad Nacional de Córdoba, Medina Allende s/n, X5000HUA Córdoba, Argentina
- Instituto
de Física Enrique Gaviola (IFEG), CONICET, Medina Allende
s/n, X5000HUA, Córdoba, Argentina
| | - Santiago Agustín Maldonado Ochoa
- Facultad
de Matemática, Física, Astronomía y Computación, Universidad Nacional de Córdoba, Medina Allende s/n, X5000HUA Córdoba, Argentina
- Instituto
de Física Enrique Gaviola (IFEG), CONICET, Medina Allende
s/n, X5000HUA, Córdoba, Argentina
| | - Franco Martín Zanotto
- Departamento
de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
- Instituto
de Investigaciones en Fisicoquímica de Córdoba
(INFIQC), CONICET, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Sergio Alberto Dassie
- Departamento
de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
- Instituto
de Investigaciones en Fisicoquímica de Córdoba
(INFIQC), CONICET, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Rodolfo Hector Acosta
- Facultad
de Matemática, Física, Astronomía y Computación, Universidad Nacional de Córdoba, Medina Allende s/n, X5000HUA Córdoba, Argentina
- Instituto
de Física Enrique Gaviola (IFEG), CONICET, Medina Allende
s/n, X5000HUA, Córdoba, Argentina
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Romanel SA, Cunha DA, Castro EV, Barbosa LL. Time domain nuclear magnetic resonance (TD-NMR): A new methodology to quantify adulteration of gasoline. Microchem J 2018. [DOI: 10.1016/j.microc.2018.03.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Kock FV, Machado MP, Athayde GP, Colnago LA, Barbosa LL. Quantification of paramagnetic ions in solution using time domain NMR. PROS and CONS to optical emission spectrometry method. Microchem J 2018. [DOI: 10.1016/j.microc.2017.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Ferreira Gomes B, Ferreira da Silva P, Silva Lobo CM, da Silva Santos M, Colnago LA. Strong magnetoelectrolysis effect during electrochemical reaction monitored in situ by high-resolution NMR spectroscopy. Anal Chim Acta 2017; 983:91-95. [DOI: 10.1016/j.aca.2017.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 06/14/2017] [Accepted: 06/15/2017] [Indexed: 10/19/2022]
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15
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Wang Q, Gao R, Liu S. Topology optimization based design of unilateral NMR for generating a remote homogeneous field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 279:51-59. [PMID: 28463746 DOI: 10.1016/j.jmr.2017.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 04/07/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
This paper presents a topology optimization based design method for the design of unilateral nuclear magnetic resonance (NMR), with which a remote homogeneous field can be obtained. The topology optimization is actualized by seeking out the optimal layout of ferromagnetic materials within a given design domain. The design objective is defined as generating a sensitive magnetic field with optimal homogeneity and maximal field strength within a required region of interest (ROI). The sensitivity of the objective function with respect to the design variables is derived and the method for solving the optimization problem is presented. A design example is provided to illustrate the utility of the design method, specifically the ability to improve the quality of the magnetic field over the required ROI by determining the optimal structural topology for the ferromagnetic poles. Both in simulations and experiments, the sensitive region of the magnetic field achieves about 2 times larger than that of the reference design, validating validates the feasibility of the design method.
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Affiliation(s)
- Qi Wang
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
| | - Renjing Gao
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
| | - Shutian Liu
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China.
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Rapid method for monitoring chitosan coagulation using low-field NMR relaxometry. Carbohydr Polym 2016; 150:1-4. [DOI: 10.1016/j.carbpol.2016.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 04/28/2016] [Accepted: 05/04/2016] [Indexed: 11/23/2022]
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17
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Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods. Int J Anal Chem 2016; 2016:8256437. [PMID: 27293437 PMCID: PMC4886064 DOI: 10.1155/2016/8256437] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 04/24/2016] [Indexed: 11/18/2022] Open
Abstract
We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu(2+), Ni(2+), Cr(3+), and Mn(2+), and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10(-5) mol L(-1)). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces.
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