Simultaneous Detection of Hydroquinone and Catechol at a Three-Dimensional Graphene-Modified Glassy Carbon Electrode

Three-dimensional graphene (3DG) is presented as an excellent electrocatalyst for the simultaneous detection of hydroquinone (HQ) and catechol (CC) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Morphology and structure of 3DG were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Compared with the bare glassy carbon electrode (GCE), the 3DG-modified GCE exhibits better electrocatalytic activity in the redox reaction of HQ and CC. The 3DG-modified GCE detects both isomers selectively and sensitively by DPV and CV, latter showing a peak-to-peak separation of 190 mV. The detection limits for HQ and CC can reach 0.35 and 0.6 μM (S/N = 3), respectively, with wide linear ranges of 1-1000 μM in the presence of 50 μM of the respective other isomer. This work provides a strategy for the development of high-performance electrochemical sensors.