Controlling of graphene size for better electrochemical sensors

Here, we report on the production of graphene oxides (GO) with controlled lateral sizes using different exfoliation methodologies and their influence on electroanalytical responses. Their structures, morphologies and functional groups were characterized. The GO thin films, deposited on indium tin oxide (ITO) electrodes, were electrochemically reduced to reduced graphene oxide (rGO). The thin films were applied as chronoamperometric sensors for ascorbic acid. The rGO-TS, obtained by tip sonication, exhibited expressive low limits of detection (LD) and quantification (LQ), 0.90 ± 0.35 and 2.90 ± 0.12 μmol L⁻¹, respectively, good reproducibility and minimal (or no) interference. The rGO-TS thin film also showed low LD and LQ for N-acetylcysteine detection, 6.59 ± 1.36 and 21.97 ± 4.55 μmol L⁻¹, respectively. The results of the optimized rGO-TS thin film were attributed to its better conductivity and higher edge ratio. This work represents an investigation into the effect of both GO and rGO lateral size on sensor performance.