Abstract
The interaction of macrocyclic compounds like crown ethers and UO22+ has been studied by electrochemical methods. A modified carbon paste electrode incorporating benzo-15-crown-5 (B15C5) was used to evaluate the electron transfer reaction of UO22+ by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Electrochemical impedance studies showed that charge transfer resistance was less for the B15C5-modified electrode than for the plain carbon paste electrode (PCPE). On the basis of these observations, a UO22+-sensitive crown ether chemically modified electrode (CME) for trace analysis was fabricated and investigated in aqueous solutions. It was found that a 5 B15C5CME for UO22+ showed a better voltammetric response than did the PCPE. UO22+ could be quantified at sub-μg/mL levels by differential pulse voltammetry with a detection limit of 0.03 μg/mL. By differential pulse adsorptive stripping voltammetry, UO22+ could be quantified in the working range of 0.002-0.2 μg/mL, with a detection limit of 1.1 μg/L. Simultaneous determination of UO22+, Pb2+, and Cd2+ was possible. The method was successfully applied to the determination of UO22+ in synthetic, as well as real, samples; the results were found to be comparable to those obtained by inductively coupled plasma-atomic emission spectroscopy.
Development of a Carbon Paste Electrode Containing Benzo-15-Crown-5 for Trace Determination of the Uranyl Ion by Using a Voltammetric Technique