Adsorbent Assisted in Situ Electrocatalysis: An Ultra-Sensitive Detection of As(III) in Water at Fe3O4 Nanosphere Densely Decorated with Au Nanoparticles

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• 作者：Juan Wei ; Shan-Shan Li ; Zheng Guo ; Xing Chen ; Jin-Huai Liu ; Xing-Jiu Huang
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：January 19, 2016
• 年：2016
• 卷：88
• 期：2
• 页码：1154-1161
• 全文大小：473K
• ISSN：1520-6882

文摘

Most gold nanoparticle-based electrodes have been utilized for the analysis of highly toxic As(III), while nano-Fe₃O₄ materials are currently attracting considerable interest as an adsorbent for the removal of As(III). However, the combination of gold nanoparticles with Fe₃O₄ nanoadsorbents for stripping voltammetry is, to the best of our knowledge, unexplored. Here, a sensing interface for ultrasensitive detection of As(III) is designed and constructed by abundantly dispersing Au nanoparticles (Au NPs) on the surface of the Fe₃O₄ nanosphere. The Au@Fe₃O₄ nanospheres are covered by the room temperature ionic liquid (RTIL) and then modified on the screen-printed carbon electrode (SPCE). By combining the excellent catalytic properties of the Au nanoparticles (～3–9 nm in diameter) with the good adsorption capacity of Fe₃O₄ nanospheres toward As(III), as well as the good conductivity of RTIL, the Au@Fe₃O₄-RTIL shows excellent performance in the detection of arsenic under nearly neutral conditions without modifying the morphology of the sensing interface. Through optimization of the experimental conditions, an ultrahigh sensitivity of 458.66 μA ppb^–1 cm^–2 from 0.1 to 1 ppb with a detection limit (3σ method) of 0.0022 ppb was obtained. The reproducibility and reliability of the Au@Fe₃O₄-RTIL sensing interface was also evaluated with good results. Finally, we used this platform to analyze real samples.