Microparticle-based iridium oxide ultramicroelectrodes for pH sensing and imaging
Microparticle-based iridium oxide ultramicroelectrodes for pH sensing and imaging
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DOI：
10.1016/j.jelechem.2007.06.022
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发表时间：
2007-11-01
影响因子：
4.5
通讯作者：
Wipf, David O.
中科院分区：
文献类型：
--
作者：
El-Giar, Emad Ei-Deen M.;Wipf, David O.
在本文中，我们提出了一种简单、相对廉价、可重现性好的方法来构建氧化铱(IrOx)-pH灵敏超微电极(UME)。在这种方法中，pH敏感层是基于Ir微粒(直径10µm)在0.5M H_2SO_4中以3.0V/S的电压循环形成的IrOx薄膜，用这种方法制备的IrOx-pH微传感器化学稳定、均匀，在2-12 pH范围内对H+表现出快速和线性的响应，室温下具有超能斯特斜率(-+/-7 mV/pH)。PH响应是可重复性的，并在2个月内保持稳定。Fe(CN)(3-)(6)、Ru(NH3)(3+)(6)等氧化还原离子共存对测定影响不大，但Ni2+有明显的pH漂移。这些pH敏感的UMES在成像铸铁样品表面氧还原反应引起的pH变化中得到了应用。(C)2007 Elsevier B.V.保留所有权利。
In this paper, we present a simple, relatively inexpensive, and reproducible method for the construction of iridium oxide (IrOx)-pH sensitive ultramicroelectrodes (UMEs). In this method, the pH sensing layer is based on an IrOx film formed by potential cycling of iridium microparticles (diameter < 10 mu m) in 0.5 M H2SO4 at 3.0 V/s. The IrOx-pH microsensors prepared this way are chemically stable, uniform, and exhibit rapid and linear response to H+ over the range 2-12 pH with a super-Nernstian slope (-64 +/- 7 mV/pH) at room temperature. The pH response is reproducible and remains stable over a period of 2 months. Coexistence of redox ions such as Fe(CN)(3-)(6) and Ru(NH3)(3+)(6) has little influence on the determination, however Ni2+ does produce an apparent pH shift. The application of these pHsensitive UMEs is demonstrated in imaging the pH changes due to the oxygen reduction reaction at the surface of a cast iron sample. (C) 2007 Elsevier B.V. All rights reserved.