Electrochemical determination of dopamine by poly (methyl orange) shape memory alloy modified carbon paste electrode

Abstract

We have successfully prepared 50Ni-30Ti-20Hf shape memory alloy powders using a high-energy planetary ball mill for 20 h by wet milling. The fabricated shape memory alloy powders were characterized by X-ray diffraction (XRD), and scanning electron microscope (SEM) to investigate the phases present and the morphology of the powders respectively. The use of 50Ni-30Ti-20Hf (nitinol) shape memory alloy powders as electro-catalytic materials is a unique and new idea. We are the first researchers to use nitinol powders as dopamine (DA) electrochemical sensors. For better electrochemical oxidation and higher current response of DA, we have electro-polymerized the surface of nitinol-modified carbon paste electrode (MCPE) with methyl orange (MO). Using poly(MO)-NiTiHf-MCPE, we have determined the DA using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) respectively. The calculated active surface area for BCPE, NiTiHf-MCPE, and the poly(MO)NiTiHf-MCPE were found to be 0.044, 0.089, and 0.098 cm 2 respectively. The electro-polymerized nitinol MCPE not only increased the surface area but also increased the electron transfer kinetics. Our results confirmed the participation of 2 electrons and 2 protons in the electrochemical redox reaction.