Screen-printed electrodes (SPEs)
The DropSens electrodes incorporate a three-electrode cell configuration
printed on ceramic substrates (dimensions: 3.4 × 1.0 × 0.05 cm;
length × width × height) and were previously described [21]. Both
working (disk-shaped 4 mm diameter) and counter-electrodes were
made of carbon inks, whereas pseudoreference electrode and electric
contacts were made of silver.
SPEs were modified by drop-casting of 10 μl of graphene oxide
dispersions on the working electrode surface, leaving it to dry at room
temperature. The solvent has to be completely evaporated before the
electrochemical assays. Voltammetric measurements on SPEs were
performed by placing a 50 μl drop of the corresponding electrolyte
solution to the working area.