In this work we report the sensitive electroanalytical detection of uranium(VI) in aqueous solutions. Uranium commonly exists in aqueous solutions in the form of its oxo ion, uranyl (U(VI)O-2(2+)). The detection of uranyl has been accomplished by us through its deposition upon reduction by two electrons to the insoluble UO2 using a bare disk gold macroelectrode and anodic stripping voltammetry (ASV). This gave an unsatisfactory detection limit of ca. 1 x 10(-5) M uranyl. Moreover, the evolution of hydrogen bubbles blocked the electrode surface as a result of water reduction at negative deposition potential (-0.7 V vs Ag/AgCl). The application of a 25 mu m diameter Au microwire electrode on which UO2 precipitated at negative potential (-1.2 V) improved substantially the detection limit. Further improvement was accomplished by vibrating the microwire working electrode, which increased the amounts of UO2 deposition due to decreasing the diffusion layer. The effect of the vibrating amplitude and frequency on the electroanalytical response was studied and optimized. Eventually, a detection limit of ca. 1 x 10(-9) M uranyl was achieved using a 5 min deposition time, -1.2 V deposition potential, and vibrating the electrode at frequency of 250 Hz and amplitude of 6 V.
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机译：在这项工作中，我们报告了水溶液中铀（VI）的灵敏电分析检测。铀通常以其氧代离子铀酰（U（VI）O-2（2+））的形式存在于水溶液中。铀酰的检测是通过使用裸盘金大电极和阳极溶出伏安法（ASV）将两个电子还原成不溶的UO2使其沉积而完成的。这样给出的检测限不能令人满意。 1 x 10（-5）呋喃基此外，由于在负沉积电势下（-0.7 V对Ag / AgCl）的水分减少，氢气泡的释放阻塞了电极表面。使用直径为25μm的Au微丝电极，其上的UO2以负电势（-1.2 V）沉淀，大大提高了检测极限。通过振动微线工作电极可以实现进一步的改进，这是由于减小了扩散层而增加了UO2的沉积量。研究和优化了振动幅度和频率对电分析响应的影响。最终，检测限为使用5分钟的沉积时间，-1.2 V的沉积电位并以250 Hz的频率和6 V的振幅振动电极，即可获得1 x 10（-9）M呋喃基。
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