A glassy carbon electrode was modified with nickel-ferrite magnetic nanoparticles and decorated with
multiwall carbon nanotubes (NiFe2O4–MWCNTs). Differential pulse voltammetry was then used to
investigate the electrochemical behavior of epinephrine at the surface of the modified electrode. The
properties of the nanocomposite were also characterized using different techniques. The electrode
showed an excellent synergic effect on epinephrine oxidation. At the optimum pH level, the electrode's
response in 0.1 mol L
1 phosphate solution was proportional to the concentration of epinephrine in the
range of 0.9–800.0 mmol L
1 with a detection limit of 0.09 mmol L
1. The effects of different potentially
interfering substances on the epinephrine signal were also studied. Finally, the sensor was evaluated with
respect to its reproducibility and stability. It was found that the modified electrode had a good sensitivity,
selectivity, and reproducibility for the determination of epinephrine in real samples.