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Chen H, Smetana B, Novák V, Zhang Y, Sokolov SV, Kätelhön E, Luo Z, Zhu M, Compton RG. Removing 65 Years of Approximation in Rotating Ring Disk Electrode Theory with Physics-Informed Neural Networks. J Phys Chem Lett 2024; 15:6315-6324. [PMID: 38856185 PMCID: PMC11194821 DOI: 10.1021/acs.jpclett.4c01258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/02/2024] [Accepted: 06/04/2024] [Indexed: 06/11/2024]
Abstract
The rotating Ring Disk Electrode (RRDE), since its introduction in 1959 by Frumkin and Nekrasov, has become indispensable with diverse applications in electrochemistry, catalysis, and material science. The collection efficiency (N ) is an important parameter extracted from the ring and disk currents of the RRDE, providing valuable information about reaction mechanism, kinetics, and pathways. The theoretical prediction of N is a challenging task: requiring solution of the complete convective diffusion mass transport equation with complex velocity profiles. Previous efforts, including by Albery and Bruckenstein who developed the most widely used analytical equations, heavily relied on approximations by removing radial diffusion and using approximate velocity profiles. 65 years after the introduction of RRDE, we employ a physics-informed neural network to solve the complete convective diffusion mass transport equation, to reveal the formerly neglected edge effects and velocity corrections on N , and to provide a guideline where conventional approximation is applicable.
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Affiliation(s)
- Haotian Chen
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, Great
Britain
| | - Bedřich Smetana
- Department
of Chemistry and Physico-chemical processes, Faculty of Materials
Science and Technology, VSB - Technical
University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic
| | - Vlastimil Novák
- Department
of Chemistry and Physico-chemical processes, Faculty of Materials
Science and Technology, VSB - Technical
University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic
| | - Yuanmin Zhang
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, Great
Britain
| | - Stanislav V. Sokolov
- St John’s
College, University of Oxford, St Giles’, Oxford OX1 3JP, Great Britain
| | - Enno Kätelhön
- Independent
Researcher, Offenbach am Main 63067, Germany
| | - Zhiyao Luo
- Department
of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom
| | - Mingcheng Zhu
- Department
of Computing, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Richard G. Compton
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, Great
Britain
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Hildebrand A, Merchant M, O'Hare D. Voltammetric methods for electrochemical characterization and quantification of artemether-based antimalarials. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:161-169. [PMID: 38088798 PMCID: PMC10765968 DOI: 10.1039/d3ay01837g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/24/2023] [Indexed: 01/05/2024]
Abstract
Every year substandard and falsified (SF) artemisinin derivative-based antimalarials are responsible for the loss of 450 000 deaths and billions of GBP. The lack of infrastructure and funds to support pharmaceutical quality control in many low-and-middle-income countries contributes to this problem. This work assesses fitness for purpose of voltammetric methods for identification and quantification of artemether in the presence of excipients. Electrochemical characterization of artemether using cyclic voltammetry shows that the reduction of artemether is chemically irreversible within the potential range of -0.4 V to -1.4 V. A chronocoulometric quantification algorithm for artemether is created and tested with pure artemether, as well as filtered and unfiltered Riamet® tablets. Filtration of Riamet® tablets provides no additional benefit for the quantification of artemether in Riamet®. In addition, artemether's response to pH indicates possible protonation and coupled homogeneous chemistry. Finally, sodium sulfite is an effective means of removing dissolved oxygen and improving artemether signal resolution in air-equilibrated PBS. This concludes that electrochemical analysis is a promising method for artemether identification and quantification.
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Affiliation(s)
- Anna Hildebrand
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
| | - Mariam Merchant
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
| | - Danny O'Hare
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
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Britz D, Strutwolf J. Use of the Saul'yev method for the digital simulation of chronoamperometry at the disk electrode, in the presence of homogeneous chemical reactions. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.06.146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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4
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Use of the Saul’yev method for the digital simulation of chronoamperometry and linear sweep voltammetry at the ultramicrodisk electrode. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.10.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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The impedance spectroscopy response for a reversible electrode reaction based on diffusion limited chronoamperometry at an inlaid disk electrode. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Surface concentration nonuniformities resulting from chronoamperometry of a reversible reaction at an ultramicrodisk electrode. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Bieniasz L. A New Theory of Potential Step Chronoamperometry at a Microdisk Electrode: Complete Explicit Semi-Analytical Formulae for the Faradaic Current Density and the Faradaic Current. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.03.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Britz D, Strutwolf J. Digital simulation of chronoamperometry at a disk electrode under a flat polymer film containing an enzyme. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2014.11.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Planar diffusion to macro disc electrodes—what electrode size is required for the Cottrell and Randles-Sevcik equations to apply quantitatively? J Solid State Electrochem 2014. [DOI: 10.1007/s10008-014-2664-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Laborda E, González J, Molina Á. Recent advances on the theory of pulse techniques: A mini review. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2014.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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CARNEIRO-NETO EB, SIKORA MS, PEREIRA EC, LOPES MC. Probing the Numerical Convergence of a Commercial Finite Element Software in Electrochemical Simulations. ELECTROCHEMISTRY 2014. [DOI: 10.5796/electrochemistry.82.966] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Digital simulation of chronoamperometry at an electrode within a hemispherical polymer drop containing an enzyme: comparison of a hemispherical with a flat disk electrode. Biosens Bioelectron 2013; 50:269-77. [PMID: 23871876 DOI: 10.1016/j.bios.2013.06.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/24/2013] [Accepted: 06/27/2013] [Indexed: 02/06/2023]
Abstract
Current-time and steady state current behaviour was simulated for the cases of a hemispherical and flat inlaid disk electrodes located under a hemispherical polymer drop containing an enzyme which converts a substrate diffusing into the drop into a product that is electroactive at the electrode. As well, a cylindrical electrode with length much greater than its diameter and coated with a layer of polymer/enzyme was treated. The ratio of steady state currents at the hemispherical to the disk electrode is not, as has sometimes been assumed, always equal to π/2; indeed this is only approached for polymer drops with large spillover ratio, that is, having a radius much larger than that of the electrodes. Steady state currents for all electrode geometries (including the cylinder) go through a maximum for some spillover ratio and then approach a constant value for larger spillover ratios. This constant value is the same as that for the diffusion limited current in a semi-infinite medium. For a cylindrical electrode, the steady state current tends towards zero for large spillover ratios.
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