Investigation of Sensitivity Against Different Flavonoid Derivatives of Aminophenyl-Modified Glassy Carbon Sensor Electrode and Antioxidant Activities

The electrochemical behaviors of 10 structurally different flavonoids (quercetin, galangin, chrysin, 3-hydroxyflavone, naringenin, luteolin, apigenin, flavone, kaempferol, and naringin) on a glassy carbon electrode were studied by cyclic voltammetry. In the current study, nitrophenyl diazonium salt has been synthesized from p-nitrophenylamine. One millimolar prepared nitrophenyl diazonium salt (in 100 mM tetrabutylammonium tetrafluoroborate) in acetonitrile was used to modify the glassy carbon electrode. Nitro groups have been reduced to amine groups in 100 mM HCl medium on the nitrophenyl-modified glassy carbon electrode surface. Although nitrophenyl-modified glassy carbon electrode surface was electro-inactive, it is activated by reducing the nitro group into amine group. And then, aminophenyl-modified glassy carbon electrode surface has been used for the determination of antioxidant activities of 10 flavonoid derivatives with cyclic voltammetry technique. The activity sequence of the investigated, structurally different, flavonoids follows the sequence: quercetin > galangin > chrysin > 3-hydroxyflavone > naringenin > luteolin > apigenin > flavone > kaempferol > naringin.