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This work presents the simultaneous determination of catechol (CC) and hydroquinone (HQ), employing a modified glassy carbon electrode with tetraruthenated oxovanadium (IV) porphyrin. The GCE was modified by electropolymerization of {VOTPyP[RuCl 3 (dppb)] 4 } porphyrin, onto the GCE surface, by cyclic voltammetry. The modified electrode, labeled as VOTPRu-GCE, showed two pairs of well-defined redox peaks for the electrochemical processes of catechol and hydroquinone. In bare GCE, the potential difference (ΔE p ) of CC and HQ were 469 mV and 457 mV, respectively, while with VOTPRu-GCE the potential difference decreased to 29 mV and 30 mV, indicating that the redox processes were reversible onto the VOTPRu-GCE surface. With differential pulse voltammetry, it was possible to simultaneously determine the CC and HQ, with peak-to-peak potential separation of 129 mV, in 0.1 mol L −1 acetate buffer (pH 4.75). Under the optimized conditions, the calibration curves were obtained in the linear concentration ranges of 2–38 μmol L −1 for both isomers using the VOTPRu-GCE, which showed high sensitivity in the determination of CC and HQ, 12.73 and 15.91 μA μmol L −1 cm −2 , respectively. The detection limits were 0.41 and 0.55 μmol L −1 for CC and HQ, respectively. |
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