Tailoring 3D-printed sensor properties with reduced-graphene oxide: improved conductive filaments.

The development of a tailored filament is reported composed of reduced graphene oxide (rGO) and carbon black (CB) in a polylactic acid (PLA) matrix and its use in the production of electrochemical sensors. The electrodes containing rGO showed superior performance when compared with  those prepared in the absence of this material. Physicochemical and electrochemical characterizations of the electrodes showed the successful incorporation of both rGO and CB and an improved conductivity in the presence of rGO (lower resistance to charge transfer). As a proof-of-concept, the developed electrodes were applied to the detection of the forensic analytes TNT and cocaine. The electrodes containing rGO presented a superior analytical performance for both TNT and cocaine detection, showing the lower limit of detection values (0.22 and 2.1 µmol L, respectively) in comparison with pure CB-PLA electrodes (0.93 and 11.3 µmol L, respectively). Besides, better-defined redox peaks were observed, especially for TNT, as well as increased sensitivity for both molecules.