This work presents the analytical method development for total reducing sugars determination in residual water samples obtained from sugarcane processing for ethanol production. This method was developed using pulsed amperometry with a glassy carbon electrode modified with graphene oxide containing copper nanoparticles. With pulsed amperometry detection was achieved a limit of detection of 6.4 x 10(-6) mol L-1. The amperometric sensitivity was 1.6 x 10(-2) A mol(-1) L. The recovery study showed that the method has good accuracy and repeatability, with recovery of 92.8 x 0.5%. Experiment results obtained showed that the sensor has good long-term stability, sensitivity and is interference free, and the method developed is simple and fast. (C) 2015 Elsevier Ltd. All rights reserved.