Ali Babaei - Department of Chemistry, Arak University, Arak, P.O. Box ۳۸۱۵۶-۸-۸۳۴۹, Iran.Research Center for Nanotechnology, Arak University, Arak, P.O. Box ۳۸۱۵۶-۸-۸۳۴۹, Iran
Nastaran Ebrahimi - Department of Chemistry, Arak University, Arak, P.O. Box ۳۸۱۵۶-۸-۸۳۴۹, Iran
Masoud Sohrabi - Department of Chemistry, Arak University, Arak, P.O. Box ۳۸۱۵۶-۸-۸۳۴۹, Iran

Phenolic compounds are carcinogenic, toxic, teratogenic and mutagenic. These materials prevent the growth of microorganisms and 1 mg l-1 of phenol would cause significantly affect to aquatic life. Therefore determinations of phenolic compounds in environments are important research area. In this work, graphene oxide (GO) and CuO nano sheets (CuO NSs) were prepared and used for modification of the carbon paste electrode (CPE). The poly-eriochrome black T (PEBT) film was electrodeposited at the surface of the GO/CuONSs/CPE. The modified electrode (PEBT/GO/CuONSs/CPE) was used as an electrochemical sensor for simultaneous determination of 4-Aminophenol (4-AP) and 2, 3-Xylenol (XL). Differential pulse voltammetry method at the optimum conditions showed that the oxidation peak currents were linearly dependent on the 4-AP and XL concentrations in the ranges of 2-150 and 20-450 μM, respectively. The PEBT/GO/CuONSs/CPE offered some advantages such as good stability convenient preparation and high sensitivity towards electrochemical determination of the 4-AP and XL. The applicability of the sensor was also demonstrated for simultaneous determination of 4-AP and XL in real samples with satisfactory results.