Electrochemical determination of serotonin on glassy carbon electrode modified with various graphene nanomaterials

Graphene nanosheets can be produced from easily available starting materials. We synthesized several chemically different types of graphene nanosheet for use as electrocatalysts and characterized their electrochemical properties. We evaluated the surface morphologies of the graphene nanosheets via X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (SEM), and examined their electrocatalytic activities using electrochemical impedance spectroscopy (EIS). The results were compared with those for other graphene nanosheets, and the efficiency for the electrochemical detection of serotonin, known as an important neurotransmitter, was also studied. Electrocatalytic activities were verified by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CA). A wide variation of results was observed for each of the graphene nanosheets prepared by using three different reductants. Among these graphene nanosheets, RGO1, that was reduced by hydrazine and ammonia solution as a reductant, exhibited high sensitivity, good selectivity, low detection limit, fast response time, and stability.