Figure 2: (a) Cyclic voltammograms of 5 mM Fe at scan rate of 100 mV/s (A) on bare electrode, (B) on p-AP-Au electrode. (b) Nyquist plots in 5 mM Fe at open circuit potential using frequency range of 10 kHz to 10 mHz (A) on bare electrode, (B) on p-AP-Au electrode. (c) An electrical equivalent circuit for both a bare and a modified electrode which comprises a series resistance (resistance of solution and of ohmic contacts), an interfacial film resistance , an interfacial film capacity , a resistance related to the charge transfer rate of redox reactions at the functionalized electrode , a constant phase element (CPE) related to the capacitance of the functionalized Au electrode/electrolyte interface.