Simultaneous determination of dihydroxybenzene isomers based on polymer film modified glassy carbon electrode

Recently, new materials for simultaneous determination of HQ and CC were used to modify the electrodes, including carbon nanotubes, mesoporous Pt, mesoporous carbon, graphene etc. However, it is still a challenge to explor novel electrode materials for the simultaneous determination of HQ and CC with wider linear range and higher stability[1].Here in, we report a simple method of simultaneous detection of hydroquinone (HQ) and catechol (CC) detection by covering a glassy carbon electrode (GCE) with an electropolymerized layer of 4-(2-pyridylazo)-resorcinol. The surface morphology of the electrodes has been studied by scanning electron microscopy. Compared with the bare glassy carbon electrode (GCE), the electrodes modified with 4-(2-pyridylazo)-resorcinol showed enhanced electrochemical performance toward HQ and CC in differential pulse voltammetric (DPV) measurements because of their enlarged surface area, enhanced electron-transfer rate and increased active sites. Under the optimized condition, a linear dynamic range of 0.1μmol dm−3 to 50 μmol dm−3 range for hydroquinone with the detection limit of 24 nM and from 0.1 μmol dm−3 to 50 μmol dm−3 for catechol with the detection limit of 63 nM were obtained. Compared with some recently reported electrochemical sensors based on graphene composites, the modified electrode exhibits higher sensitivity, a much lower detection limit and a comparable linear range for the simultaneous determination of HQ and CC. Moreover, The present method was applied to the simultaneous determination of HQ and CC in rain and tap water samples, which make it a promising candidate for designing an effective dihydroxybenzene sensor.