Browsing by Subject "ITIES"

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    Impact Experiments at the Interface between Two Immiscible Electrolyte Solutions (ITIES)
    (Elsevier, 2020-11-30) Laborda Ochando, Eduardo; Molina Gómez, Ángela; Química Física; Facultad de Química
    Within the field of single-entity electrochemistry through so-called impact experiments, the use of soft interfaces can be a valuable and advantageous complement to conventional solid microelectrodes, as recently demonstrated for both hard and soft micro- and nano-particles. Additionally, this approach can offer a new platform for fundamental studies of key aspects of electronic and ionic transfers across liquid-liquid interfaces, with applications in relevant biological, technological and industrial systems. Experimental results are reviewed and discussed under the light of theoretical treatments here revisited or developed.
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    Sensing and characterization of neurotransmitter 2-phenylethylamine based on facilitated ion transfer at solvent polymeric membranes using different electrochemical techniques
    (Elsevier, 2016) Ortuño Sánchez-Pedreño, Joaquín Ángel; Olmos Martínez, José Manuel; Torralba Peñalver, Encarnación; Molina Gómez, María de los Ángeles; Química Analítica
    Square Wave Voltammetry (SWV), chronoamperometry and chronocoulometry are exploited to take advantage of their different performance characteristics in the determination, characterization and sensing of the neurotransmitter 2-phenylethylamine (PEA), based on the ion transfer of its protonated form at a solvent polymeric membrane facilitated by dibenzo-18-crown-6 (DB18C6). The general voltammetric features characterizing the PEA+ transfer are established by SWV and the standard ion transfer potential, diffusion coefficient and complexation constant value between PEA+ and DB18C6 are calculated from the SWV recordings. Next, the performance of double pulse chronoamperometry and double pulse chronocoulometry for the determination of PEA based on its facilitated ion transfer is studied. Limits of detection between 3.6 and 9.2 µM for chronoamperometry and 1.7 and 2.7 for chronocoulometry are obtained. The influence of common ions on both chronoamperometric and chronocoulometric determination is also considered. The sensitivity ratio values found between foreign cations and PEA+ are 0.05, 0.3 and 0.2 for Na+, K+ and H+, respectively, whereas no interference was observed for Li+. In addition, the electrode is tested as a sensor for monitoring PEA+ concentration using a pulsed-amperometric mode. Interestingly, a simple procedure to extend the range of linear response of quantitative electrochemical techniques significantly based on a previous analysis of chronoamperometric recordings is proposed and successfully tested.