Graphene was coated on glassy carbon electrode (GCE) and cobalt hexacyanoferrate was then electrodeposited on the modified electrode to fabricate electrochemical sensor. Scanning electron microscope was used to characterize the nano-composite film. The electrochemical behaviors of hydroquinone (HQ), catechol (CT) and resorcinol (RS) on the modified electrode were investigated by cyclic voltammetry. The oxidation currents of CT, RS and HQ increased remarkably compared with those obtained at the bare GCE and graphene modified GCE. Differential pulse voltammetry was used for the simultaneous determination of CT, RS and HQ in their ternary mixture. The concentration of HQ, CT and RS showed good linear relationships with the oxidation peak current in the range of 1.0×10^－6～1.5×10^－4 mol/L, 1.0×10^－6～ 2.0×10^－4 mol/L and 3.5×10^－6～2.5×10^－4 mol/L, with correlation coefficients of R＝0.991, 0.993 and 0.992, respectively. The limits of detection for HQ, CT and RS were 2.0×10^－7, 2.1×10^－7 and 3.5×10^－7 mol/L (S/N＝3), respectively. The developed method was used to determination of water samples with recoveries of 95.6%～106.1%.

Key words: graphene, cobalt hexacyanoferrate, hydroquinone, catechol, resorcinol, simultaneous determin ation