A new route for the integration of a graphene/diazonium/PEDOT electrode towards antioxidant biomarker detection

• Monolayer graphene synthesized by chemical vapor deposition on a Si/Pt substrate
• Electrochemical grafting of a diazonium/PEDOT film conferring the selectivity to the electrode
• Selective detection (~ 380 mV) of ascorbic/uric acids by differential pulse voltammetry
• Sensitivity of 2.40 and 2.75 μA cm−2 μM−1 for AA and UA, respectively

A new route for the integration of a graphene-based electrode on a silicon substrate was studied for the simultaneous detection and assay of ascorbic (AA) and uric (UA) acids. Graphene was synthesized by catalytic chemical vapour deposition (CVD) from methane as carbon feedstock onto both platinum foils and supported thin platinum films on silicon wafers which were used as catalyst. Graphene was characterized by Raman spectroscopy and electron microscopies. The resulting electrodes were further functionalized by successive electrodeposition of a stabilizing diazonium layer and a poly(3,4-ethylenedioxythiophene) (PEDOT) conductive film. AA and UA determination on such modified electrode was performed either by cyclic voltammetry or by differential pulse voltammetry. In the latter case, the selectivity was about 380 mV and the sensitivity was 2.40 and 2.75 μA cm−2 μM−1 for AA and UA, respectively. The present study shows that monolayer graphene allows a greater sensitivity of AA and UA detection than that observed with modified glassy carbon electrode.

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