A graphene oxide–mesoporous MnO2 nanocomposite modified glassy carbon electrode as a novel and efficient voltammetric sensor for simultaneous determination of hydroquinone and catechol

A new facile preparation method of graphene oxide–mesoporous MnO2 (GO–MnO2) nanocomplex was developed here. The GO–MnO2 was used as a new electrode material for the fabrication of voltammetric sensor for sensitive simultaneous determination of hydroquinone (HQ) and catechol (CC), which exhibited significantly decreased peak-to-peak separations of ca. 34 and 36 mV for HQ and CC, respectively between oxidation and reduction waves in cyclic voltammetry. In differential pulse voltammetric measurements, the GO–MnO2 based sensor could separate the oxidation peak potentials of HQ and CC by about 115 mV though the bare electrode gave a single broad response, which was related to the higher surface area and catalytic ability of GO–MnO2. The oxidation peak current of HQ was linear over the range from 0.01 to 0.7 μM in the presence of 0.1 μM CC, and the oxidation peak current of CC was linear over the range from 0.03 to 1.0 μM in the presence of 0.13 μM HQ. The detection limits (S/N = 3) for HQ and CC were 7.0 and 10.0 nM, respectively. The proposed sensor was successfully applied to the simultaneous determination of HQ and CC in artificial wastewater samples.