Browsing by Author "Gidi, Leyla"

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    Electrochemical Detection of Sulfite by Electroreduction Using a Carbon Paste Electrode Binder with N-octylpyridinium Hexafluorophosphate Ionic Liquid
    (2022) Bustos Villalobos, Maicol; Ibarra, Jose; Gidi, Leyla; Cavieres, Valentina; Jesus Aguirre, Maria; Ramirez, Galo; Arce, Roxana
    Sulfite is a widely used additive in food and beverages, and its maximum content is limited by food regulations. For this reason, determining the sulfite concentration using fast, low-cost techniques is a current challenge. This work describes the behavior of a sensor based on an electrode formed by carbon nanotubes an ionic liquid as binder, which by electrochemical reduction, allows detecting sulfite with a detection limit of 1.6 +/- 0.05 mmol L-1 and presents adequate sensitivity. The advantage of detecting sulfite by reduction and not by oxidation is that the presence of antioxidants such as ascorbic acid does not affect the measurement. The electrode shown here is low-cost and easy to manufacture, robust, and stable.
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    Electrodetermination of Gallic Acid Using Multi-walled Carbon Nanotube Paste Electrodes and N-Octylpyridinium Hexafluorophosphate
    (WILEY-V C H VERLAG GMBH, 2022) Gidi, Leyla; Honores, Jessica; Ibarra, Jose; Jesus Aguirre, Maria; Arce, Roxana; Ramirez, Galo
    In this work, the determination of gallic acid was performed using surface-renewable carbon paste electrodes fabricated with multi-walled carbon nanotubes (MWCNT) and a mixture of N-octylpyridinium hexafluorophosphate (OPyPF6) ionic liquid with mineral oil (MO) as binder. This system shows remarkable amperometric sensor characteristics and promotes a better electronic transfer. An electroanalytical study of gallic acid shows a linear range from 4.98 +/- 0.25 to 74.1 +/- 2.2 mu mol L-1, with R-2=0.9958 and an experiment a limit of detection of 2.70 +/- 0.08 mu mol L-1 (S/N=3), and a sensitivity of 0.029 mu A mu mol(-1) L.
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    Hydrogen evolution reaction highly electrocatalyzed by MWCNT/N-octylpyridinum hexafluorophosphate metal-free system
    (2021) Gidi, Leyla; Arce, Roxana; Ibarra, Jose; Isaacs, M.; Aguirre, M. J.; Ramirez, Galo
    A mixed electrocatalyst that consists of multi walled carbon nanotubes (MWCNTs) and the ionic liquid (IL) N-octylpyridinum hexafluorophosphate (OPyPF6) as binder (MWCNT/IL system) was used in the study of hydrogen evolution reaction. This electrocatalyst was compared to graphite/mineral oil (Gr), graphite/OPyPF6 (Gr/IL), MWCNT/mineral oil (MWCNT) systems. All systems were characterized by cyclic voltammetry determining that MWCNT/IL system is highly electrocatalytic (E onset = -0.3 V vs Ag/AgCl) in relation to the other systems studied containing MWCNT or IL separately. The presence of each of the components that form the electrodic surface is corroborated by XRD, Raman, and FESEM-EDX, and it is demonstrated by chronoamperometric analysis that MWCNT/IL system is highly stable. The efficiency of the electrode, determined by its electrocatalytic activity, is confirmed by the quantification by gas chromatography of the hydrogen produced. Moreover, an elevated TON value (16274) and faradaic efficiency close to 60% are calculated, in comparison to other electrocatalysts found in literature. All these attractive properties are complemented by the fact that the MWCNT/IL system is simple, novel and easy to prepare. (C) 2021 Elsevier Ltd. All rights reserved.
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    Leyla Gidi, Camila Canales, Maria J. Aguirre, Francisco Armijo, and Galo Ramirez, Four-Electron Reduction of Oxygen Electrocatalyzed by a Mixture of Porphyrin Complexes onto Glassy Carbon Electrode (vol 13, pg 1666, 2018)
    (ESG, 2018) Gidi, Leyla; Canales, Camila; Aguirre, Maria J.; Armijo, Francisco; Ramirez, Galo
    © 2018 The Authors.The exact received date of the paper is 24 October 2017 year.
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    Study of the Hydrogen Evolution Reaction Using Ionic Liquid/Cobalt Porphyrin Systems as Electro and Photoelectrocatalysts
    (MDPI, 2020) Gidi, Leyla; Honores, Jessica; Ibarra, Jose; Arce, Roxana; Aguirre, M. J.; Ramirez, Galo
    In this work, the design and manufacture of graphite paste (Gr) electrodes is carried out, including N-octylpyridinium hexafluorophosphate (OPyPF6) ionic liquid (IL) as binder and modification with Co-octaethylporphyrin (Co), in order to study the hydrogen evolution reaction (HER) in the absence and presence of light. The system is characterized by XRD and FESEM-EDX (Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy), confirming the presence of all the components of the system in the electrode surface. The studies carried out in this investigation confirm that a photoelectrocatalytic system towards HER is obtained. The system is stable, efficient and easy to prepare. Through cyclic voltammetry and electrochemical impedance spectroscopy, was determined that these electrodes improve their electrochemical and electrical properties upon the addition of OPyPF6. These effects improve even more when the systems are modified with Co porphyrin. It is also observed that when the systems are irradiated at 395 nm, the redox process is favored in energy terms, as well as in its electrical properties. Through gas chromatography, it was determined that the graphite paste electrode in the presence of ionic liquid and porphyrin (Gr/IL/Co) presents a high turnover number (TON) value (6342 and 6827 in presence of light) in comparison to similar systems reported.