Graphene platelets (GNPs) for electrochemical sensing (a) (A) and (B) Transmission electron microscopy (TEM) images of GNPs at different magnifications; (C) high-resolution TEM image of GNPs showing a nanoflake with a knife-edge or conical structure with open graphitic planes; (D) energy-dispersive X-ray spectrum, showing the chemical composition of GNP films. (b) (A) and (B) Cyclic voltammetry profiles of GNPs and bare GCEs, respectively, in a solution of 50 mM PBS buffer at pH 7, containing 1 mM ascorbic acid, 0.1 mM dopamine, and 0.1 mM uric acid [152].