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Author: search.filters.author.Chaiyasith, SuwanSubject: search.filters.subject.Electrochemical sensor

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    A Co3O4 nano-octahedron modified fluorine doped tin oxide electrochemical sensor for detection of benzobicyclon
    (2018-03-15)
    Puangjan, Apinya
    ;
    Chaiyasith, Suwan
    Unique Co<inf>3</inf>O<inf>4</inf> nano-octahedrons for modifying electrode were synthesized through simple chemical reaction. This versatile Co<inf>3</inf>O<inf>4</inf> nanostructure possesses the combined advantages of morphological stability and high porosity that can buffer volume change during electrochemical cycles, shorten diffusion path of electron transport, and exhibit remarkable overall electrochemical performance. Samples were characterized by field transmission electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffractometry, Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy. An electrode modified by this material was used for detection of benzobicyclon. Square wave voltammetry showed that there was a linear relationship between peak current and concentration in the range of 10.00–582.96 μmol L<sup>−1</sup> with a detection limit (S/N = 3) of 0.38 μmol L<sup>−1</sup>. The modified electrode was used for detection of benzobicyclon in brown rice and rice straw samples with satisfactory recovery, reproducibility and stability. Modified electrodes reported in the literature that were prepared by different methods resulted in other kinds of surface morphologies that did not exhibit the same level of performance.
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    An efficient ZrO2/Co3O4/reduced graphene oxide nanocomposite electrochemical sensor for simultaneous determination of gallic acid, caffeic acid and protocatechuic acid natural antioxidants
    (2016-09-01)
    Puangjan, Apinya
    ;
    Chaiyasith, Suwan
    A novel efficient ZrO<inf>2</inf>/Co<inf>3</inf>O<inf>4</inf>/reduced graphene oxide (rGO) nanocomposite catalyst was prepared by a reflux method. Then, the nanocomposite was positively characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Afterward, the nanocomposite was fabricated into an electrochemical sensor by casting it onto the surface of a fluorine doped tin oxide (FTO) electrode. The ZrO<inf>2</inf>/Co<inf>3</inf>O<inf>4</inf>/rGO nanocomposite/FTO exhibited a synergistic catalytic effect toward oxidation of gallic acid (GA), caffeic acid (CA) and protocatechuic acid (PA) with the oxidation peak currents increasing linearly with concentrations in the range of 6.24-477.68 nmol L<sup>-1</sup>, 2.48-524.90 nmol L<sup>-1</sup> and 5.40-424.96 nmol L<sup>-1</sup> and the limits of detection (S/N = 3) of 1.56 nmol L<sup>-1</sup> for GA, 0.62 nmol L<sup>-1</sup> for CA and 1.35 nmol L<sup>-1</sup> for PA. The proposed electrode was then successfully used for simultaneous determination of the three species in fruit juice, rice and tea samples with satisfactory recoveries, showing the feasibility of its use for electrochemical sensing application.