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Issue 11, 2003
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Ion selectivity obtained under voltammetric conditions when a TCNQ chemically modified electrode is presented with aqueous solutions containing tetraalkylammonium cations

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Abstract

The voltammetry of 7,7,8,8-tetracyanoquinodimethane (TCNQ) at an electrode-microparticle-aqueous (electrolye) interface has been proposed as a cation sensor on the basis that changes in electrolyte cation (analyte) concentrations result in reproducible shifts in the TCNQ0/− reversible potential. In order to probe the ion selective nature of the TCNQ sensor, the voltammetric response towards a series of tetraalkylammonium cations of variable size and hydrophobicity were studied. Both the thermodynamics (reversible potential) and kinetics (voltammetric peak separation) of the TCNQ0/− system were strongly dependant on the identity of the R4N+ cation. The reversible potential responded in a Nernstian manner to changes in cation concentration. When presented with mixed-analyte solutions, the TCNQ system exhibited Nicolsky type (or competitive) form of selectivity. However, the selectivity coefficients found in the present study were far greater than previously reported with group I cations. The order obtained for the tetraalkylammonium series indicates that ion selectivity is predominantly based on analyte solvation thermodyanics rather than a specific ionophore mechanism.

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Publication details

The article was received on 31 Jul 2003, accepted on 14 Oct 2003 and first published on 27 Oct 2003


Article type: Paper
DOI: 10.1039/B309078G
Citation: Analyst, 2003,128, 1386-1390
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    Ion selectivity obtained under voltammetric conditions when a TCNQ chemically modified electrode is presented with aqueous solutions containing tetraalkylammonium cations

    T. J. Wooster and A. M. Bond, Analyst, 2003, 128, 1386
    DOI: 10.1039/B309078G

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