Voltammetric behavior and the determination of quercetin at a flowerlike Co3O4 nanoparticles modified glassy carbon electrode

Flowerlike Co3O4 nanoparticles were used as a modifier on the glassy carbon electrode to fabricate a quercetin (Qu) sensor. The morphology and crystallinity of the prepared Co3O4 material were investigated by scanning electron microscopy and X-ray diffraction. Electrochemical behavior of Qu at the sensor was studied by cyclic voltammetry and semi-derivative voltammetry. Results suggested that the modified electrode exhibited a strong electrocatalytic activity toward the redox of Qu. The electron transfer coefficient (alpha), the number of electron transfer (n), and the diffusion coefficient (D) of Qu at the sensor were calculated. Under the optimum conditions, the catalytic peak currents of Qu were linearly dependent on the concentrations of Qu in the range from 5.0 x 10(-7) to 3.3 x 10(-4) M, with a detection limit of 1.0 x 10(-7) M. This proposed method was successfully applied to determine the quercetin concentration in Ginkgo leaf tablet and human urine samples.