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Published on: November 15, 2016
Nanostructured TiO₂ Carbon Paste Based Sensor for Determination of Methyldopa
Luane Ferreira Garcia1, Carlos Eduardo Peixoto da Cunha2, Emily Kussmaul Gonçalves Moreno3
1Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74690-970, Brazil. luane.fg@hotmail.com.
Abstract:
Methyldopa is a catecholamine widely used in the treatment of mild to moderate hypertension whose determination in pharmaceutical formulae is of upmost importance for dose precision. Henceforth, a low-cost carbon paste electrode (CPE) consisting of graphite powder obtained from a crushed pencil stick was herein modified with nanostructured TiO₂ (TiO₂@CPE) aiming for the detection of methyldopa in pharmaceutical samples. The TiO₂-modified graphite powder was characterized by scanning electron microscopy and X-ray diffraction, which demonstrated the oxide nanostructured morphology. Results evidenced that sensitivity was nonetheless increased due to electro-catalytic effects promoted by metal modification, and linear response obtained by differential pulse voltammetry for the determination of methyldopa (pH = 5.0) was between 10⁻180 μmol/L (Limit of Detection = 1 μmol/L) with the TiO₂@CPE sensor. Furthermore, the constructed sensor was successfully applied in the detection of methyldopa in pharmaceutical formulations and excipients promoted no interference, that indicates that the sensor herein developed is a cheap, reliable, and useful strategy to detect methyldopa in pharmaceutical samples, and may also be applicable in determinations of similar compounds.
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