▎ 摘　　要

The manioc starch (MS) product extracted of many Manihot species, presents low cost and film formation capability. In this work, we report the decoration of MS thin film with reduced graphene oxide to form a novel composite, which we used to modify a glassy carbon electrode for phenolic compounds detection. The characterization of the nanostructured biopolymeric film was performed by scanning electron and atomic force microscopy, electrochemical impedance, ultraviolet-visible and Fourier transform infrared spectroscopies, dynamic light scattering and cyclic voltammetry techniques. Under optimal experimental conditions, the peak currents were independently studied in the concentration range of 0.5 to 200 mu mol L-1 and 0.5 to 74 mu mol L-1 with a limit of detection of 0.07 mu mol L-1 and 0.04 mu mol L-1, for dopamine and catechol, respectively, as proof of concept. MS proved to be a great asset for supporting thin film for electroanalytical devices, which were tested in water and synthetic urine samples, with satisfactory results.