A novel electro-chemical method was designed to develop a simple, inexpensive, selective and sensitive electrochemical sensor by modifying carbon paste electrode for the simultaneous determination of dopamine (DA) without the interference of ascorbic acid (AA). Chemically modified carbon paste electrode was prepared by the incorporation of iron-silver bimetallic nanoparticles (Fe-AgNps/Fe-AgCTABMCPE) in presence of cationic surfactant Cetyltrimethyl ammonium Bromide (CTAB) was used for the surface modification and the properties of the modified electrode was studied by using the analytical techniques like cyclic voltammetry (CV), differential pulse voltammetry (DPV) and scanning electron microscope (SEM) image. The modified electrode showed a couple of distinct and well-defined redox peaks for DA and AA mixture, which was not observed with bare carbon paste electrode in 0.1 M phosphate buffer solution (PBS) of pH 7.0 with a scan rate of 50 mVs-1. There was a good enhancement in redox peak current for DA by 3 folds when compared to bare carbon paste electrode. The anodic peak current vs. scan rate was found to be linear with a correlation coefficient of 0.9951 indicating that the reaction is a diffusion controlled process. The anodic peak current (Ipa) showed a linear relation with concentration of DA with a correlation coefficient of 0.9986 and the detection limit was found to be 3.52×10-5 M. The detection limit of DA is 0.01 µM with a correlation coefficient of 0.9953 and AA is 0.4 µM with a correlation coefficient of 0.9952 respectively. Hence this chemically modified electrochemical sensor showed a reliable result for the voltammetric determination of AA in the presence of DA and it can be ideal for the practical application of DA in human blood serum and dopamine hydro chloride injection.
Fe-Ag bimetallic nanoparticles, Cetyltrimethyl ammonium bromide surfactant, Dopamine, Ascorbic acid, Scanning electron microscopy, Voltammetric techniques