shows the cyclic voltammogram of Au-PCB and
FGO-Au-PCB in 100 mM TES buffer (pH 7.0). As can be
seen in Fig. 4 (a), GOx modified Au-PCB did not show any
obvious redox peak. On the other hand, redox peaks clearly
appeared as FGO-Au-PCB is used. The applied voltage of 0.6
V was selected based on cyclic voltammogram where peak
current is appeared at that voltage. Fig. 4 (b) displays glucose
concentration vs. current with using three different
FGO-Au-PCB chips. The linear response with respect to
various concentrations of glucose in TES buffer indicates that
enzyme immobilized on the surface of electrodes provide the
suitable environment for electron transfer between the glucose
and sensor surface which is attributable to the detection of
hydrogen peroxide obtained during the enzymatic reaction
(GOx: glucose + O2 → gluconolactone + H2O2). Fig. 5 shows
the current level versus the addition of ascorbic acid to
measure the current stability in the existence of interfering
material. As can be seen in Fig. 5 there were no current level
changes observable with increase of concentration of ascorbic
acid from 5 mg/dL to 20 mg/dL. The nafion layer under GOX
layer could prevent ascorbic acid from passing through the
FGO coating.