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ARPN Journal of Science and Technology >> Volume 7, Issue 1, January 2017

ARPN Journal of Science and Technology


Effect of Chitosan on the Volta Metric Response as an Electrochemical Sensor for the Detection of Iodide in Aqueous Solutions

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Author Matheus Pedro R, Belandria Olga M, Vincent Alain B, Linares Ledy
ISSN 2225-7217
On Pages 710-715
Volume No. 4
Issue No. 11
Issue Date December 01, 2014
Publishing Date December 01, 2014
Keywords Chitosan, Glass Carbon, Electrochemistry, Voltammetry, Iodide



Abstract

Iodide determination on carbon glass surfaces (CEMWG) and carbon glass modified with chitosan (GCEMCC) was carried out in chitosan concentrations of 0.5, 1.0, 1.5, 2.0 and 2.5% (Fluka, high molecular weight) in acetic acid 2.0 M. Commercial potassium iodide (LAB-LINE 99.5% purity) was used for both electrodes at a concentration of 5.0 μg/mL. Cyclic Voltammetries (CV) and Differential Pulse Voltammetries (DPV) were carried out at pH 5.49. Obtained results show that with increasing concentrations of chitosan, the peak current (ip) increases, reaching a maximum of 37.5 μA at a concentration of 1%. From here on, the peak current lowers as the chitosan concentration increases. When the chitosan concentration reaches 2.5%, the peak current is only 4.64 μA, which can be explained because of the chitosan high viscosity, slowing the electrons free movement towards the electrode surface, and thus, a smaller current response is obtained. When VC were carried out on the CEMWG and GCEMCC electrodes at 1% chitosan, using 0.2 M buffer acetic acid-sodium acetate as electrolyte solution (pH 5.49) and 2.0 μg/mL of KI, the oxidation signal of iodide was observed at +0.80V for the GCEMCC electrode, but was not observed for the CEMWG one, which indicates an increase in sensitivity of the modified electrode. DPV were also performed for both electrodes, at KI concentrations between 0.0 and 2.0 μg/mL, in order to get the minimum concentration of iodide that could be detected; the signal


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