Preparation of the modified electrodes
The GCE was carefully polished with alumina (0.05 lm) on a
polishing cloth and rinsed with acetone and double distilled water
before use. A homogeneous suspension of MWNT (0.5 mg mL1)
was obtained by ultrasonic dispersion for 1 h in 1% sodium dodecyl
sulfate. Electrode modification was performed by covering the GCE
with a 5 lL MWNT suspension, without any electrochemical
precondition of the electrode surface, and evaporating to dryness.