Electrochemical determination of uranyl ion using a graphene paste electrode

Uranium is a radioactive and toxic element and commonly exists in the environment in the U(VI) and U(IV) oxidation states. The most stable chemical species in aqueous solution under oxic conditions is the uranyl ion UO22+. In this research an electrochemcal sensor based on chemically reduced graphene oxide (RGO) for sensetive determination of UO22+ was prepared. The electrochemical behavior and determination of uranyl ion on surface of graphene paste electrode in the potential range of -0.8 to 0.8 (v) was studied by cyclic and differential pulse voltammetery. The effects of various parameters such as pH and scan rate were investigated. The response of the sensor was found to be linear in the range of uranyl concentrations from 1.0 to 600 M. The detection limit (S/N=3) is calculated 0.7 M. A sensor shows a good repeatability (RSD of 0.9% (n=6)). The sensor was successfully applied for determination of uranyl in water and soil samples.