pinjari shaikshavali

A sensitive electrochemical sensor was made by the electro polymerization of Lcystine (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.

In this work, the glassy carbon electrode (GCE) was modified with multi-walled carbon nanotubes (MWCNTs) by drop casting process, and it was used as a working electrode for the electrochemical determination of 3,5-dinitrobenzoic acid (3,5-DNBA) in an electrolytic solution containing a cetyl trimethyl ammonium bromide (CTAB). This process was examined by using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. The modified electrode showed an excellent electrocatalytic activity and sensitivity towards the investigation of 3,5-DNBA reduction behavior in the presence of CTAB. The electrochemical process was irreversible and was controlled by adsorption. The effect of pH, scan rate and concentration were studied at the surface of MWCNTs/GCE. The electrochemical behavior of 3,5-DNBA was studied in the presence and absence of CTAB at MWCNTs/GCE in PBS having pH 6.5. The LOD (limit of detection) and LOQ (limit of quantification) of 3,5-DNBA was found to be as 4.94×10-6 M, 1.65×10-5 M respectively. The surface coverage area concentration (Γ) of MWCNTs/GCE was calculated and was found to be as 1.3146×10-8 mole/cm2. By using electrochemical impedance spectroscopy (EIS), the interfacial electron transfer behavior of 3,5-DNBA was studied at different types of electrode surfaces.