Center for Electrochemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States.
Anal Chem. 2012 Jun 5;84(11):5159-63. doi: 10.1021/ac300863r. Epub 2012 May 23.
In this paper, we present a technique to rapidly and directly examine ultramicroelectrodes (UMEs) by white light vertical scanning interferometry (VSI). This technique is especially useful in obtaining topographic information with nanometer resolution without destruction or modification of the UME and in recognizing tips where the metal is recessed below the insulating sheath. Two gold UMEs, one with a metal radius a = 25 μm and relative insulating sheath radius RG = 2 and the other with a = 5 μm and RG = ∼1.5, were examined, and the average depth of the gold recessions was determined to be 1.15 μm and 910 nm, respectively. Electrodeposition of gold was performed to fill the recessed hole, and the depth was reduced to ∼200 nm. With the electrodeposited gold electrode and a conventional microelectrode (a = 25 μm) as a tip and substrate, respectively, a tip/substrate distance, d, of 600 nm was achieved allowing scanning electrochemical microscopy (SECM) in positive feedback mode at a close distance, which is useful for measuring fast kinetics.
在本文中，我们提出了一种通过白光垂直扫描干涉测量（VSI）快速直接检测超微电极（UMEs）的技术。该技术特别适用于在不破坏或修改 UME 的情况下获得具有纳米分辨率的形貌信息，并识别金属在绝缘鞘下方凹陷的尖端。我们检查了两个金 UME，一个金属半径 a = 25 μm，相对绝缘鞘半径 RG = 2，另一个 a = 5 μm，RG = ∼1.5，分别确定了金凹陷的平均深度为 1.15 μm 和 910 nm。进行金电沉积以填充凹陷的孔，深度降低到约 200 nm。用沉积的金电极和常规微电极（a = 25 μm）分别作为尖端和基底，实现了 600nm 的尖端/基底距离 d，允许在近距离以正反馈模式进行扫描电化学显微镜（SECM），这对于测量快速动力学很有用。
