Abstract In this paper an electrochemical sensor was prepared by modification of carbon paste electrode with a nanostructured mesoporous material. The electrooxidation of norepinephrine (NE), paracetamol (AC) and folic acid (FA) was studied at this electrode by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). CV experiments showed that the oxidation overpotential of these substances decreased and their oxidation current increased sharply at the modified electrode rather than bare carbon paste electrode. The overlapped DPV peaks of NE, AC and FA has been resolved into three separated peaks by the electrochemical sensor. DPV peak currents increased linearly with concentration over the range of 7.0 × 10 −8 to 2.0 × 10 −3 , 5.0 × 10 −7 to 2.2 × 10 −3 and 5.0 × 10 −6 to 2.0 × 10 −3 M for NE, AC, and FA, respectively. Also, the proposed electrochemical sensor was used for the determination of these substances in some real samples.