Electrochemical study on screen-printed carbon electrodes with modification by iron nanoparticles in Fe(CN)(6) (4-/3-) redox system.

The remarkable enhancement of electron transfer on screen-printed carbon electrodes (SPCEs) with modification by iron nanoparticles (Fe(nano)), coupled with Fe(CN)(6) (4-/3-) redox species, was characterized with an increase of electroactive area (A (ea)) at electrode surface together with a decrease of heterogeneous electron transfer rate constant (k degrees ) in the system. Hence, Fe(nano)-Fe(CN)(6) (3-) SPCEs with deposition of glucose oxidase (GOD) demonstrated a higher sensitivity to various glucose concentrations than Fe(CN)(6) (3-)/GOD-deposited SPCEs. In addition, an inhibited diffusion current from cyclic voltammograms was also observed with an increase in redox concentration and complicated the estimation of A (ea). Further analysis by the electrochemical impedance method, it was shown that this effect might be resulted from the electrode surface blocking by the products of activated complex decomposition.