Here, a simple one-step solvothermal procedure was employed to synthesize a nanocomposite containing graphene-nanosheets and CdS quantum dots (GNs-CdS QDs). The electrochemical oxidation of chlorpromazine (CPZ) to chlorpromazine-sulfoxide (CPZ-SO) onto a GNs-CdS QDs/ionic liquid (IL) nanocomposite modified glassy carbon (GC) electrode give rise to redoxactive products which showed excellent electrocatalytic and photoelectrocatalytic activity toward NADH oxidation at reduced overpotential. A linear response up to 200 mM was obtained for photoamperometric determination of NADH with detection limit 1 mM. Immobilizing alcohol dehydrogenase(ADH) onto the modified electrode via a simple cross linking procedure, the photoelectrochemical capability of the proposed system toward ethanol biosensing was clearly shown.
