期刊
SENSORS AND ACTUATORS B-CHEMICAL
卷 156, 期 2, 页码 689-694出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.snb.2011.02.019
关键词
Electrochemical sensor; Uranium detection; Chemically modified electrodes
资金
- European Union
- Hellenic Ministry of Education, Life Long Learning and religious affairs
The development of a preconcentrating sensor based on 6-O-palmitoyl-L-ascorbic acid (PAA)-modified graphite (GRA) electrodes for the determination of uranium is described. PM, a water insoluble compound of ascorbic acid, was immobilized onto the surface of the GRA electrodes through physical adsorption from acetone solutions. Uranium was accumulated by heterogeneous complexation (10 min, in 0.1 M H(3)BO(3), pH 4.3) and then, it was reduced by means of a differential pulse voltammetric scan in 0.1 M H(3)BO(3), pH 3.4. Alternatively, the performance of both preconcentration and voltammetric steps in a single run, at 0.1 M H(3)BO(3), pH 3.65, was also examined; however, in this case the observed current signals were lower by 30%. The experimental variables were investigated and under the selected conditions, a linear calibration curve in the range 2.7-67.5 mu g L(-1) U(VI) was constructed (r(2) = 0.9981). The 3 sigma limit of detection and the relative standard deviation of the method were 1.8 mu g L(-1) U(VI) and 8% (n = 5, 20 mu g L(-1) U(VI), preconcentration time 10 min), respectively. By increasing the preconcentration time to 30 min, a limit of detection as low as 0.26 mu g L(-1) U(VI) can be achieved. The effect of potential interferences was also examined. The accuracy of the method was established by recovery studies in inoculated tap and lake water samples. A simple and fast procedure based on filtering of the sample through a C-18 microcolumn was successfully used to remove the organic matter from the lake water samples. (C) 2011 Elsevier B.V. All rights reserved.
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