Voltammetric determination of vitamin B6 (pyridoxine) at a graphite screen-printed electrode modified with graphene oxide/Fe3O4@SiO2 nanocomposite

The preparation and study of electrochemical properties of a graphite screen-printed electrode (SPE) modified with the GO/Fe3O4@SiO2 (GO is graphene oxide) nanocomposites are described. The morphologies of the GO/Fe3O4@SiO2 nanocomposites were examined by scanning electron microscopy. The electrochemical oxidation of vitamin B-6 (pyridoxine) on SPE modified with the GO/Fe3O4@SiO2 nanocomposite was investigated by cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. Under optimum conditions (pH 7.0), the vitamin B-6 oxidation at the surface of the modified SPE occurs at a potential about 190 mV less positive than that at the unmodified SPE. A linear voltammetric response for vitamin B-6 was obtained in the concentration range 1.0.10(-6)-9.0.10(4) L-1 with a detection limit of 5.2.10 (7) mol L-1 using differential pulse voltammetry. The developed sensor was also successfully applied for determination of trace level of vitamin B-6 in both the standard vitamin B-6 sample and biological samples (urine).