Voltammetry ion-transfer

Previously, Osaka and coworkers [29-31] employed ion-transfer voltammetry to determine the standard ion-transfer potentials (Aq 4> ) of heteropoly- and isopolyoxome-talate anions (in short, polyanions) at the nitrobenzene (NB)/W and 1,2-dichloroethane (1,2-DCE)/W interfaces is directly related to the transfer energy by... 

NB/W interface, which were calculated from the extraction data using an extra thermodynamic assumption. Afterward, a newly developed electrochemical technique (so-called ion-transfer voltammetry) with a polarizable O/W interface was employed to determine... 

In deriving theoretical equations of the current-potential (or time) curves of ion-transfer voltammetry of a dibase we shall make the following assumptions ... 

Y. Kubota, Ion-Transfer Voltammetry of Organic Compounds at Organic Solvent/Water Interface. Study on Partition of Organic Compounds between Organic Solvent and Water, MS thesis, Fukui Prefectural University, Fukui 1998. 

Maeda et al. [29,31] studied the mechanism of potential oscillation across the nitrobenzene membrane by ion-transfer voltammetry. In spite of the different liquid membranes used in this study, their methods for clarifying the oscillation mechanism should be useful for obtaining more detailed information on the octanol membrane. This matter will be considered in a future article. 

Complexation of Pb(II) by cyclic thioethers facilitates reversible interfacial transfer in ion-transfer voltammetry for the water-nitrobenzene and water-1,2-dichloroethane systems [95, 96]. 

Kakutani et al. described an ion-transfer voltammetry and potentiometry method for the determination of acetylcholine with the interface between polymer-nitrobenzene gel and water [13]. The PVC-nitrobenzene gel electrode was prepared as described by Osakai et al. [14]. The transfer of acetylcholine ions across the interface between the gel electrode and water was studied by cyclic voltammetry, potential-step chronoamperometry, and potentiometry. The interface between the two immiscible electrolyte solutions acted as the ion-selective electrode surface for the determination of acetylcholine ions. 

Osakai et al. used a microcomputer-controlled system for the ion transfer voltammetry procedure [20]. The system used is based on a NEC PC-9801 microcomputer, which was designed by using a polarizable oil-water interface as an ion-selective electrode surface. The system was applied to the determination of acetylcholine ion by cyclic, differential pulse, and normal pulse voltammetry at the PVC-nitrobenzene gel electrode. The amperometric measurement was carried out with voltage pulses of short durations and constant amplitude. 

In 1977 Koryta et al. [61] reported the Avalues of several common ions at the NB/W interface, which were calculated from the extraction data using an extra thermodynamic assumption. Afterward, a newly developed electrochemical technique (so-called ion-transfer voltammetry) with a polarizable O/W interface was employed to determine AGtr° w for a variety of ions [33,62-71]. In Table 4 the reliable values of AG ° >w are compiled. Regarding the ions whose AGj r° w values are available for both electrochemical and extraction measurements, the electrochemical data, which seem to be more accurate, have been chosen preferentially. For several ions, somewhat different AGf, 0 w values from electrochemical measurements have been reported, as also seen in the database provided by Girault on a website [72], In this study, however, we have carefully chosen reliable values for the respective ions, which were determined under well-defined conditions (reference electrodes, solution compositions, etc.). 

The Gibbs energy of transfer of the neutral ferrocene has been measured by a shake flask experiment and found to be equal to AG =-24.5 0.5 kl mol (K 2-10 ) > and that of ferrocinium by ion-transfer voltammetry found to be equal to 0.5 kJ moH [195]. Considering that = 0.380V [195], we have... 

Evans, N. J. Gonsalves, M. Gray, N. J. Barker, A. L. Macpherson, J. V. Unwin, P. R. Local ampero-metiic detection of K+ in aqueous solution using scanning electrochemical microscopy ion-transfer voltammetry. Electrochem Commun 2000, 2, 201-206. 

Selective amperometric microelectrodes are also obtained from a microinterface between two immiscible electrolyte solutions (ITIES) formed at the tip of a glass micropipette. These micro-ITIES behave as disk UME and allow the quantitative amperometric detection of different ions based on ion-transfer voltammetry. A K+-selective micro-ITIES successfully imaged the transport of K+ across a 50 pm diameter pore by SECM. ... 

---