title: Development of a carbon paste electrode containing benzo-15-crown-5 for trace determination of the uranyl ion by using a voltammetric technique.
abstract: The interaction of macrocyclic compounds like crown ethers and UO2(2+) 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 UO2(2+) 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 UO2(2+)-sensitive crown ether chemically modified electrode (CME) for trace analysis was fabricated and investigated in aqueous solutions. It was found that a 5% B15C5-CME for UO2(2+) showed a better voltammetric response than did the PCPE. UO2(2+) could be quantified at sub-microg/mL levels by differential pulse voltammetry with a detection limit of 0.03 microg/mL. By differential pulse adsorptive stripping voltammetry, UO2(2+) could be quantified in the working range of 0.002-0.2 microg/mL, with a detection limit of 1.1 microg/L. Simultaneous determination of UO2(2+), Pb(2+), and Cd(2+) was possible. The method was successfully applied to the determination of UO2(2+) in synthetic, as well as real, samples; the results were found to be comparable to those obtained by inductively coupled plasma-atomic emission spectroscopy.
authors.affiliation: University of Mumbai, Department of Chemistry, Vidyanagari, Santacruz (East), Mumbai-400 098, India. akschbu@yahoo.com
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Agrahari
authors.forename: Sangita D
authors.initials: SD
authors.lastname: Kumar
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Srivastava
mesh_terms: D002244:Carbon; D043844:Crown Ethers; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D007477:Ions / Q000032:analysis*; D009556:Niobium / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014131:Trace Elements / Q000032:analysis*; D014501:Uranium / Q000032:analysis*
chemical_list: D043844:Crown Ethers; D007477:Ions; D014131:Trace Elements; D009556:Niobium; D014501:Uranium; D002244:Carbon