Carbon nanotube-modified glassy carbon electrode for anodic stripping voltammetric detection of Uranyle

A multi-wall carbon nanotube (MWNT) modified glassy carbon electrode (GCE) is described for the measurement of trace levels of uranium by anodic stripping voltammetry. In a pH 4.4 NaAc-Hac buffer containing 0.010 mol L-1 Mg(NO3)(2), UO22+ was adsorbed onto the surface of a MWNT film coated glassy carbon electrode and then reduced at -0.40 V vs. Ag/AgCl. During the positive potential sweep the reduced uranium was oxidized and a well-defined stripping peak appeared at + 0.20 V vs. Ag/AgCl. Low concentrations of Mg2+ significantly enhanced the stripping peak currents since they induced UO22+ to adsorb at the electrode surface. The response was linear up to 1.2 X 9 10(-7) mol L-1 and the relative standard deviation at 2.0 x 9 10(-8) mol L-1 uranium was 5.2%. Potential interferences were examined. The attractive behavior of the new "mercury-free'' uranium sensor holds promise for on-site environmental and industrial monitoring of uranium.