From clay- to organoclay-film modified electrodes: tuning charge selectivity in ion exchange voltammetry

Abstract : The surface of two natural smectite-type clay samples was chemically modified by covalent grafting of amine groups, by reaction with γ-aminopropyltriethoxysilane, which were easily protonated in HCl medium. Multisweep cyclic voltammograms of clay-film modified glassy carbon electrodes made of either the raw clays or the propylammonium-functionalized samples exposed to Ru(NH3)63+ or Fe(CN)63− electroactive probes were obtained. The results indicated a permselective behavior of these clay and organoclay-films based on either favorable or unfavorable electrostatic interactions. The cation-exchanging raw clay film modified electrodes exhibited accumulation properties for Ru(NH3)63+ species while rejecting Fe(CN)63−, whereas the anion-exchanging organoclay coatings acted as a barrier against Ru(NH3)63+ while increasing dramatically the concentration of Fe(CN)63− species at the electrode surface. Strong binding of the probe to the organoclays resulted in a potential shift of ca. 0.1 V of the voltammetric signals characteristic of the Fe(CN)63−/4− couple in the anodic direction. Their good preconcentration efficiency at low analyte concentration highlighted their interest for electroanalytical applications.
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https://hal.univ-lorraine.fr/hal-01941985
Contributor : Alain Walcarius <>
Submitted on : Sunday, December 2, 2018 - 8:04:01 PM
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Ignas Tonle, Emmanuel Ngameni, Alain Walcarius. From clay- to organoclay-film modified electrodes: tuning charge selectivity in ion exchange voltammetry. Electrochimica Acta, Elsevier, 2004, 49 (20), pp.3435-3443. ⟨10.1016/j.electacta.2004.03.012⟩. ⟨hal-01941985⟩

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