Author/Authors :
Khajvand، Tahereh نويسنده Faculty of Chemistry, University of Mazandaran, Babolsar , , Ojan، Reza نويسنده Electroanalytical Chemistry Research Laboratory, Faculty of Chemistry, Mazandaran University, Babolsar 4741695447, Iran Ojan, Reza , Raoof، Jahan-Bakhsh نويسنده Electroanalytical Chemistry Research Laboratory, Faculty of Chemistry, Mazandaran University, Babolsar 4741695447, Iran Raoof, Jahan-Bakhsh
Abstract :
A chemically modified carbon paste electrode (MCPE) with tetrachloro-orthobenzoquinone
(TOB) was employed to study the electrocatalytic oxidation of sulfite in
aqueous solution using cyclic voltammetry (CV) and double-potential step
chronoamperometry. It has been found that under an optimum condition (pH 2.0), the
oxidation of sulfite at the surface of MCPE occurs at a potential of about 700 mV less
positive than that of an unmodified CPE. The diffusion coefficient (D) for sulfite was found
as 8.2×10-6 cm2 s-1 by chronoamperometry. The electron transfer coefficient, a, was estimated
to be 0.4 and 0.24 for the oxidation of sulfite at the surface of MCPE and unmodified CPE,
respectively. The electrocatalytic oxidation peak currents showed a linear dependence on the
sulfite concentration in the range of 1×10-4 M -4.2×10-3 M with detection limit (3s) 5.7×10-5
M by CV. This method was also used for selective determination of sulfite in weak liquor
