The nanocomposite of graphene-iron oxide-polyvinyl alcohol (PIG) was synthesized via simple one-pot hydrothermal method and was used in the modification of pencil graphite electrode for developing an electrochemical sensor. Graphene (G) and iron oxide-graphene (IG) composites were synthesized for providing a comparative study. The structural properties of the prepared PIG were studied through X-Ray diffraction (XRD) technique, whereas the morphological analysis was conducted through field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) study. The chemical states of elements present in the prepared composite were confirmed using X-ray photoelectron spectroscopy (XPS) and the functional groups present in the composite were investigated through Fourier transform infrared (FTIR) spectroscopy. The existence of iron oxide nanoparticles along with PVA polymer in PIG composite enhances the electroactive area (0.073 cm(2)) and roughness factor (0.186) along with the sensitivity of the material. The square wave voltammetry technique was used for detecting the biomolecule i.e. vitamin C.At optimized condition, the PIG modified electrode shows a high linear range (40 mu M-4100 mu M), low limit of detection (0.234 mu M) and higher sensitivity (1597.03 mu A cm(-2) mM(-1)). The PIG material also provides a good stability towards detection of vitamin C. (C) 2018 Elsevier B.V. All rights reserved.