Jahan Bakhsh Raoof - aEletroanalytical Chemistry Research Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran
Mohammad Ali Karimi - bDepartment of Chemistry, Payame Noor University, P.O. Box ۱۹۳۹۵-۴۶۹۷, Tehran, Iran
Leila Asadian-Zarrinabadi - Department of Chemistry, Payame Noor University, P.O. Box ۱۹۳۹۵-۴۶۹۷, Tehran, Iran

The electrochemical oxidation and determination of tryptophan (Trp) and glutathione (GSH) in the presence of catechol as a homo-geneous redox in the aqueous medium were investigated at the surface of a carbon paste electrode modified with multi-walled carbon nanotube (MWCNT-CPE) using cyclic voltammetry (CV), double step potential chronoamperometry and differential pulse voltam-metry (DPV) techniques. The results of differential pulse voltammetry showed two well-resolved anodic peaks for glutathione and tryptophan which leads to voltammetric determination of each of them. The results shows the electrooxidation peak currents of GSH and Trp is linear in the concentration range of 2×10-6 M - 2.8×10-4 M and 4×10-6 M - 6×10-5 M, respectively. The kinetic parameters such as: the chemical reaction rate constant (kh) and transfer coefficient (α) were calculated 2.01×102 cm3 mol-1 s-1 and 0.31, respec-tively. Also, the apparent diffusion coefficient, Dapp, for GSH was found to be 1.95×10-6 cm2 s-1 in aqueous buffered solution. The proposed method was successfully applied for determination of glutathione and tryptophan in real sample using standard addition method

Glutathione; Tryptophan; Catechol; Multi-Walled Carbon Nanotubes