Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

the electrooxidation of cysteamine (ca) was studied by modified carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid (3,4-dhca) using cyclic voltammetry, chronoamperometry and linear sweep voltammetry. using the modified electrode, the kinetics of ca electrooxidation was considerably enhanced by lowering the anodic over-potential through a catalytic fashion. the mechanism of ca electrochemical behavior at the modified electrode surface was analyzed by various electrochemical methods in the presence of mediator. the prepared modified electrode showed voltammetric responses with high sensitivity for ca, making it very suitable for the detection of ca at trace levels. a linear dynamic range of 0.25-400 μmol l-1 for ca was obtained in buffered solutions with ph 7.0. the limit of detection was 0.09 μmol l-1.