A sensor based in a graphite–polyurethane composite electrode modified with the mesoporous nanostructured silica with hexagonal array of pores called Santa Barbara Amorphous type material (SBA‐15) containing nickel was built. The presence of Ni, incorporated during the synthesis of SBA‐15, resulted in an increase in sensitivity when compared to the other electrodes based on the unmodified SBA‐15. A procedure was proposed for the determination of Cu2+ in ethanol biofuel by square wave stripping voltammetry with linear response in concentration levels of 1.0×10−8 and 1.0×10−7 mol L−1, resulting in a limit of detection of 1.83×10−10 mol L−1 and precision (RSD) of 2.09 %.