An electrochemical sensor for simultaneous determination of catechol( CC) and hydroquinone( HQ) based on carbon nanotubes( CNTs) -graphene nanosheet( GNS) hybrid film modified gold electrode ( GE) was prepared. The electrochemical behavior of CC and HQ at the CNTs-GNS modified GE was investigated by cyclic voltammetry( CV). The results showed that the electrocatalytic activity of CC and HQ was significantly enhanced by the modification of CNTs-GNS hybrid films. The electrochemical sensor based on the hybrid modified GE exhibited excellent analy...