Electrochemical fabrication and amperometric sensor application of graphene sheets

• Fabrication of graphene sheets with electrochemical processes in two electrode cell.
• Electrochemical intercalation of SDS into graphite electrode.
• Investigation of effect of intercalation potential on the quality of graphene sheets.
• Sensitive amperometric determination of nitrite at graphene/GCE.

Graphene sheets have been fabricated by applying two-step electrochemical processes in two-electrode cell system containing 0.1 M sodium dodecyl sulfate (SDS). First step is intercalation of SDS into graphite anode electrode and this process has been applied at different intercalation potential values of 1, 3, 5, and 7 V. Second step includes exfoliation of SDS-intercalated graphite electrode in the same medium by acting as cathode. Stable graphene dispersions are obtained after these two electrochemical steps. Characterization of graphene sheets have been carried out using scanning electron microscopy, electron dispersive spectroscopy, fourier transform infrared spectroscopy, UV–Vis. absorption spectroscopy, X-ray diffraction, and cyclic voltammetry techniques. Graphene sheets have been modified onto glassy carbon electrode (GCE) by drop-casting of graphene dispersion. Graphene/GCE having a good electrocatalytic activity has been used for amperometric determination of nitrite in both standard laboratory and real samples. The oxidation current density was linearly proportional to the nitrite concentration in a range between 1 and 250 μM. The sensitivity of the sensor was calculated as 0.843 μAμM−1 cm−2 with a detection limit of 0.24 μM at a signal-to-noise ratio of 3.0.