Open AccessElectrocatalytic oxidation and determination of homocysteine at carbon nanotubes modified paste electrode using dopamine as a mediator
Author(s) -
Safoora Mohammadzadeh,
Masoud Fouladgar
Publication year - 2013
Publication title -
journal of the serbian chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.227
H-Index - 45
eISSN - 1820-7421
pISSN - 0352-5139
DOI - 10.2298/jsc121019022m
Subject(s) - carbon paste electrode , detection limit , electrode , carbon nanotube , electrochemistry , chemistry , inorganic chemistry , electrocatalyst , analytical chemistry (journal) , diffusion , redox , materials science , cyclic voltammetry , chromatography , nanotechnology , physics , thermodynamics
A carbon paste electrode modified with multiwall carbon nanotubes (MWCNTPE) was prepared to study the electrocatalytic activity of dopamine (DP) in the presence of homocysteine (HCy) and it was used for determination of HCy. The diffusion coefficient of HCy (D = 6.79×10−6 cm2 s−1), and the kinetic parameters of its oxidation such as electron transfer coefficient (α = 0.46), and rate constant (kh = 7.44×102 dm3 mol-1 s-1) were also determined using electrochemical approaches. Under the optimum pH of 5.0, the peak current of oxidation of HCy at MWCNTPE in the presence of DP occurs at a potential about 530 mV and the results showed that the oxidation peak current of HCy at the modified carbon nanotubes electrode was higher than on unmodified electrode. The peak current of differential pulse voltammograms of HCy solutions increased linearly in the range of 3.0-600.0 μM HCy with the detection limit of 2.08 μM HCy. This method was also examined for determination of HCy in physiological serum and urine samples