Voltammetric behaviour of a modified electrode with azide copper octa(3-aminopropyl)octasilsesquioxane composite in the oxidation of ascorbic acid
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Data
2011
Autores
Carmo, Devaney Ribeiro do [UNESP]
Paim, Leonardo Lataro [UNESP]
Silvestrini, Daniela Rodrigues [UNESP]
Sá, Acelino Cardoso de [UNESP]
Bicalho, Urquisa de Oliveira [UNESP]
Stradiotto, Nelson Ramos [UNESP]
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Resumo
A novel nanostructured composite, azide copper octa (3-aminopropyl)octasilsesquioxane (ASCA) was incorporated into a graphite paste electrode and the electrochemical studies were conducted with cyclic voltammetry. The cyclic voltammogram of the modified graphite paste electrode with ASCA (GPE-ASCA), showed one redox couple with formal potential (E ) = 0.30 V and an irreversible process at 1.1 V (vs Ag/AgCl; NaCl 1.0 mol L-1 ; v = 20 mV s-1 ). The redox couple with (E ) = 0.30V presents an electrocatalytic response for determination of ascorbic acid. The modified electrode gives a linear range from 1.010-4 – 1.010-3 mol L-1 (r = 0.998) for the determination of ascorbic acid with detection limit of 6.910-5 mol L-1 and standard deviation of 2.3% for n = 3 . The amperometric sensitivity was 122.1 mA/mol L-1 for ascorbic acid. The application this electrode was tested and ascorbic acid in three commercial pharmaceutical product (Cebion, Cewin and Redoxon) have been determined.
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Silsesquioxane, ascorbic acid, graphite paste electrode, voltammetry, modified electrode
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International Journal of Electrochemical Science, v. 6, p. 1175-1188, 2011.