Simple and rapid determination of clonidine in pharmaceutical samples by voltammetry using a bare glassy carbon electrode |
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Authors: | Débora A R Moreira Dilton M Pimentel Mariane O B Arrieiro Sandro L Barbosa Rodrigo A B da Silva Wallans T P dos Santos |
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Institution: | 1. Departamento de Química, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Rodovia MGT 367, km 583, No. 5000, Alto da Jacuba, 39100-000 Diamantina, MG, Brazil;2. Departamento de Farmácia, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Rodovia MGT 367, km 583, No. 5000, Alto da Jacuba, 39100-000 Diamantina, MG, Brazil;3. Instituto de Química, Universidade Federal de Uberlândia, Rodovia LMG 746, km 1, 38500-000 Monte Carmelo-MG, Brazil |
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Abstract: | This work presents, for the first time, the voltammetric behavior of clonidine (CLO) drug and its determination, using an unmodified glassy carbon electrode (GCE). CLO exhibited only an irreversible oxidation process on the GCE, with peak potential at +0.85 V in pH 12 (vs Ag/AgCl). CLO oxidation process is pH-dependent and the electrochemical mechanisms on the GCE were proposed in acidic and basic medium. The determination of CLO was optimized in 0.1 mol L−1 phosphate buffer solution at pH 12.0 using differential pulse voltammetry (DPV), which provides a good linear range (0.65 to 106.00 μmol L−1) and low theoretical limit of detection (0.14 μmol L−1) for the quality control of this drug in pharmaceutical samples. In addition, stable responses of CLO at the GCE were obtained in the same day (RSD = 3.4 %; n = 5) and different days (RSD = 2.0 %; n = 3). Moreover, the determination of CLO in a pharmaceutical formulation using the proposed GCE-DPV method presented good accuracy, since the recovery was close to 100 % and the dosing result was in agreement with an official method (HPLC-UV). The proposed method demonstrates a good analytical performance for CLO determination in pharmaceutical samples, providing a faster, simpler and lower-cost alternative for quality control of CLO than other reported methods. |
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Keywords: | clonidine differential pulse voltammetry glassy carbon electrode narrow therapeutic index drugs unmodified electrode |
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