Simultaneous and sensitive electrochemical detection of dihydroxybenzene isomers with UiO-66 metal-organic framework/mesoporous carbon.

The zirconium-based MOF (UiO-66)/mesoporous carbon (MC) composite was synthesized using conventional hydrothermal method for the first time. The surface morphology and structure of UiO-66/MC composite were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A novel electrochemical sensor based on UiO-66/MC was constructed for simultaneous and sensitive determination of dihydroxybenzene isomers (DBIs) of hydroquinone (HQ), catechol (CT) and resorcinol (RS). The proposed sensor displays excellent electrocatalytic activity toward the oxidation of HQ, CT and RS. The peak-to-peak potential separations between CT and HQ, and RS and CT are 0.130V and 0.345V, respectively. Under the optimized conditions, the electrochemical sensor shows a wide linear response in the concentration range of 0.5-100μM, 0.4-100μM and 30-400μM with a detection limit of 0.056μM, 0.072μM and 3.51μM (S/N = 3) for HQ, CT and RS, respectively. In addition, the sensor has superior sensitivity and electrochemical stability along with good reproducibility and anti-interference properties. The fabricated sensor was also applied for the determination of DBIs in the real water samples with satisfying results.