Fabrication, Characterization and Application of Poly (L-Cystine)/multi Walled Carbon Nanotubes Modified Glassy Carbon Electrode towards the Simultaneous Determination of Dopamine in presence of Uric Acid and Folic Acid

A sensitive electrochemical sensor was made by the electro polymerization of L-cystine (L-Cys) on the surface of a glassy carbon electrode (GCE) followed by drop casting of multi walled carbon nano tubes (MWCNTs). The sensor was characterized by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensor showed good electrocatalytic activity towards the sensing of dopamine (DA) and simultaneously discriminated DA in presence of uric acid (UA) and folic acid (FA). The kinetic parameters, such as heterogeneous rate constant, number of electrons transfer and charge transfer coefficient values were evaluated. The effect of concentration on the DA was studied and a linear relationship was observed between the concentration verses peak currents, with a limit of detection (LOD) and limit of quantification (LOQ) values as 2.8×10-6 M and 9.6×10-6 M, respectively. The present method was successfully applied toward the recovery of DA in injection sample.