Some 4 μL of the toluene dispersion was manually dropped on the surface of the thin film Pt electrode using a micropipette, left in air for solvent evaporation, and then cured for 30 min in
an oven at 80 °C. The process was repeated seven times in order to obtain a homogeneous composite thick film over the electrode.Then, the sensor was immersed in a 0.1 M NaOH solution for 1 h in order to wet the nanocomposite and to stabilize its capacitive current.