Theoretical Investigation of Generator–Collector Microwell Arrays for Improving Electroanalytical Selectivity: Application to Selective Dopamine Detection in the Presence of Ascorbic Acid

Authors

  • Dr. Alexander Oleinick,

    1. CNRS UMR 8640 “PASTEUR”, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris 75005 (France)
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  • Feng Zhu,

    1. State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen (China)
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  • Dr. Jiawei Yan,

    1. State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen (China)
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  • Prof. Dr. Bingwei Mao,

    1. State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen (China)
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  • Prof. Dr. Irina Svir ,

    Corresponding author
    1. CNRS UMR 8640 “PASTEUR”, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris 75005 (France)
    2. Mathematical and Computer Modelling Laboratory, Kharkov National University of Radioelectronics, 14 Lenin Avenue, 61166 Kharkov (Ukraine)
    • CNRS UMR 8640 “PASTEUR”, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris 75005 (France)

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  • Prof. Dr. Christian Amatore

    Corresponding author
    1. CNRS UMR 8640 “PASTEUR”, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris 75005 (France)
    • CNRS UMR 8640 “PASTEUR”, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris 75005 (France)

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Abstract

Recessed generator–collector assemblies consisting of an array of recessed disks (generator electrodes) with a gold layer (collector electrode) deposited over the top-plane insulator reportedly allow increased selectivity and sensitivity during electrochemical detection of dopamine (DA) in the presence of ascorbic acid (AA), a situation which is frequently encountered. In sensor design, the potential of the disk electrodes is set to the wave plateau of DA, whereas the plane electrode is biased at the irreversible wave plateau of AA before the onset of the DA oxidation wave. Thus, AA is scavenged but DA is allowed to enter the nanocavities to be oxidized at the disk electrodes, and its signal is further amplified by redox cycling between disk and plane electrodes. Several different theoretical approaches are elaborated herein to analyze the behavior of the system, and their conclusions are successfully tested by experiments. This reveals the crucial role of the plane-electrode area which screens access to the recessed disks (i.e. acts as a diffusional Faraday cage) and simultaneously contributes to amplification of the analyte signal through positive feedback, as occurs in interdigitated arrays and scanning electrochemical microscopy. Simulations also allow for the evaluation of the benefits of different geometries inspired by the above design and different operating modes for increasing the sensor performance.

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