Elaboration of screen-printed microelectrodes working as generator/collector and their use in a flow cell system

A simple and cheap method has been developed to fabricate generator/collector microelectrodes. The elaboration of these electrodes consists in the deposit of consecutive layers of conductive ink and insulator by screen-printing. The two resulting working surfaces (microbands) are situated on the edge of the sensor and are separated by a very thin layer of insulator (17 μm). These microbands may be individually polarized at different potentials in order to generate a species at one of them and detect it at the other one. Cyclic voltammetry has been used to test and characterize the two working surfaces. The capacity of these dual-electrodes for working as generator/collector sensors is demonstrated by recording the generated and collected currents by chronoamperometry with a bipotentiostat. The collected current is about 30% of the generated current. These sensors have been adapted to a flow cell, allowing detection of sub-nanomoles of solute.