interfaced to a personal com-puter with PSTrace software (version 4.6) for the acquisition andprocessing of data. A three-electrode electrochemical cell of 10 mL containing the GCE or modified GCE as the working electrode, an Ag/AgCl electrode (saturated with KCl) as the reference and a Ptwire as the auxiliary electrode was used. Electrochemical mea-surements