Simultaneous determination of cysteamine and folic acid in pharmaceutical and biological samples using modified multiwall carbon nanotube paste electrode

A carbon paste electrode (CPE) chemically modified with multiwall carbon nanotubes and ferrocene (FC) was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine (CA) and folic acid (FA). This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA. The peak current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200 mu mol/L CA and 5.0-700 mu mol/L FA. The detection limits for CA and FA were 0.3 mu mol/L and 2.0 mu mol/L, respectively. The diffusion coefficient (D) and transfer coefficient (alpha) of CA were also determined. These conditions are sufficient to allow determination of CA and FA both individually and simultaneously. (C) 2011 Hassan Karimi-Maleh. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.