Sensing System Integrating Lanthanum Hydroxide Nanowires with Copper(II) Ion for Uracil and its Application

Abstract

A sensing system for uracil was constituted by using lanthanum hydroxide nanowires (LNW) as a modifier to obtain LNW modified carbon paste electrode (LNW/CPE) and by introducing copper(II) ion into supporting electrolyte to transform electroinactive uracil to electroactive uracil‐Cu(II) complex. The voltammetric behaviors of uracil in the presence of Cu(II) ion at LNW/CPE were investigated. A reduction peak of the uracil‐Cu(II) complex at −0.18 V was the two‐electron reduction of Cu(II) ion in the uracil‐Cu(II) complex; while a new oxidation peak at 0.22 V was the one‐electron oxidation of the uracil‐Cu(I) complex. Additionally, the voltammetric responses of all the complexes at LNW/CPE were more sensitive than that at carbon and multiwall carbon nanotube paste electrodes, which resulted from both the large surface effect of LNW and the chemical coordination of uracil with La(III) ion in LNW. With the sensitive oxidation peak of the uracil‐Cu(I) complex at LNW/CPE, a linear range of 4.0×10⁻⁹−3.0×10⁻⁸ mol/l for uracil was obtained along with a detection limit of 2.0×10⁻¹⁰ mol/l. The proposed system was evaluated by the determination of uracil derivatives, anticancer drug 5‐flurouracil, in pharmaceutical preparations.

Keywords:

• Uracil
• 5‐flurouracil
• lanthanum hydroxide nanowires
• copper, uracil‐Cu(I) complex
• carbon paste electrode

Acknowledgments

Financial support of the National Natural Science Foundation of P. R. China (Grant No. 20475043) is acknowledged.