Increasing the electrochemical system performance using a magnetic nanostructured sensor for simultaneous determination of l-tyrosine and epinephrine

A novel nanostructured sensor based on a carbon paste electrode (CPE) modified with iron oxide nanoparticles (CPE/Fe3O4) was devised for the simultaneous determination of L-tyrosine (LT) and epinephrine (EP). Various techniques such as X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy were used for characterization of the pure Fe3O4 nanopowders and the nanostructured modified sensor. The use of the CPE/Fe3O4 indicated that excellent electrocatalytic activity is created for the oxidation of LT and EP in 0.2 M Britton-Robinson buffer (B-R; pH = 4.0). Furthermore, the modified CPE exhibited improved electrocatalytic activity toward LT and EP in the linear range concentration of 0.4-270.0 mu M, with a detection limit of 50.0 nM and 22.0 nM, respectively. The modified electrode was applied successfully for simultaneous determination of LT and EP in human blood serum using a differential pulse voltammetry technique. Good stability and repeatability were also observed in the determination of LT and EP at the surface of the nanostructured sensor.